Objective: Obstructive sleep apnea (OSA) results in increased carotid intima-media thickness (IMT) and arterial stiffness; however, the association between adipocytokines and IMT/arterial stiffness in OSA patients is unclear.Methods: We enrolled 95 normal weight and overweight, not obese, participants from May 2018 to December 2018 in this study. All subjects underwent a carotid artery ultrasound examination and polysomnography. Blood samples were used to determine serum chemerin, adiponectin, SFRP5, and apelin levels. Correlations between two quantitative variables were assessed using the Pearson or Spearman coefficient. Stepwise models of multiple linear regression analysis were performed to assess the independent relationships.Result: IMT in OSA patients was significantly higher than in the non-snorers. There were significant differences in the arterial stiffness parameters such as distensibility coefficient (DC), compliance coefficient (CC), and pulse wave velocity (PWV). SFRP5 level was lower in OSA patients than in non-snorers. Adiponectin correlated with CC, DC, and PWV among OSA patients; however, the relationship disappeared after a multivariable adjustment. Age was independently associated with all quantitative IMT and stiffness indices. AHI and minimum oxygen saturation (Mini SaO2) were independently related to arterial stiffness.Conclusion: The quantitative IMT and carotid arterial elasticity were significantly worse among OSA patients. Age was the main independent factor correlated with quantitative IMT and arterial stiffness, and AHI and mini SaO2 were associated factors. There were no relationships between aforementioned adipocytokines and quantitative IMT/carotid arterial stiffness. Obstructive sleep apnea (OSA) is a common sleep-related breathing disorder  characteCarotid intima-media thickness (IMT) is an important marker for evaluating early atherosclerosis development . SeveralMoreover, changes in the levels of adipocytokines such as chemerin, apelin, and secreted frizzled-related protein5 (SFRP5) are important risk factors for atherosclerosis and cardiovascular diseases , 20. The2 to (1) determine the correlation between OSA and chemerin, apelin, adiponectin, and SFRP5; (2) examine the relationship between adipokines and IMT/arterial stiffness.Therefore, we conducted this study among OSA patients with BMI <30 kg/m2. The exclusion criteria were as follows: (1) coronary atherosclerotic cardiopathy, cerebrovascular disease, and other peripheral vascular diseases; (2) post-percutaneous transluminal coronary angioplasty or bypass surgery; (3) renal failure requiring hemodialysis or peritoneal dialysis; (4) chronic obstructive pulmonary disease, chronic cardiac failure, and diabetes mellitus; (5) hepatic encephalopathy and liver carcinoma and, (6) missing data. In total, 62 OSA patients were included in the study. In addition, we recruited 33 healthy volunteers without snoring from the general population. Written informed consent was obtained from all subjects following the guidelines of the National Ethics Regulation Committee and was in accordance with the Declaration of Helsinki. This study was approved by the Internal Review Board of the Institutional Ethics Committee of the Shanghai Jiao Tong University Affiliated Sixth Hospital [2018-KY-021(K)].OSA patients were consecutively recruited at the Department of Otolaryngology, Head and Neck Surgery of Shanghai Sixth People's Hospital from May 2018 to December 2018. The inclusion criteria were: (1) aged between 20 and 55 years old and, (2) BMI between 18 and 30 kg/m2 <90% and minimal oxygen saturation (Mini SaO2) were also recorded. Based on the American Academy of Sleep Medicine criteria  was performed overnight between 22:00 and 06:00 and included electrooculography, electroencephalography (EEG), electromyography (EMG), and electrocardiography. Airflow was measured using nasal and oral thermistors. We also monitored the thoracic-abdominal movements, performed finger pulse oximetry, assessed snoring using a tracheal microphone, and recorded changes in body position. Apnea was defined as a complete cessation of airflow for at least 10s  when meacriteria , AHI ≥5 Weight was measured using a weighing scale with the subject standing still in lightweight clothing and bare feet. Height was measured as the maximum distance from the feet to the highest point on the head while standing without any footwear and feet kept together. The body mass index (BMI) was calculated as weight (kilograms)/height squared (square meters).The MyLab Twice  ultrasound machine used was equipped with a 12-MHz vascular probe (LA523), which measured quantitative IMT, and quantitative arterial stiffness (QAS) capabilities automatically. The software used a complex algorithm that could process all data from the lesion as RF signals. It is suitable for the quantitative evaluation of the vessel wall's properties. All participants underwent an examination of the IMT and arterial stiffness of the bilateral common carotid artery (CCA) in the supine position with a head elevation ≤ 45° and a side tilt of 30° in order to fully expose the neck. The internal diameter of the CCA was measured in a longitudinal section. All the measurements were performed by one investigator (JLX), who was blinded to the OSA diagnosis.Each patient underwent automatic bilateral common carotid arterial measurements over six cardiac cycles. Once all six met the quality standard , their average was calculated and used as a final result for that patient. These measurements and average calculations were performed automatically and displayed on the left side of the screen, as shown in Quantitative IMT measurements were performed in a longitudinal section, strictly perpendicular to the ultrasound beam, with both arterial walls clearly visualized. A high-quality standard B-mode image was acquired and the distal 1–1.5 cm of the bilateral CCA just proximal to the bulb was measured using a computer analysis system. Automatic quantitative IMT calculation was measured in real-time by the radiofrequency reception signal  and the &β) according to the following formulae: *Ds-Dd*Dd)/[4(Ps-Pd)]; α = ln(Ps/Pd)/[(As-Ad)/Ad]; β = ln (Ps/Pd)/[(Ds-Dd)/Dd], where As = systolic area, Ad = diastolic area, Ds = systolic diameter, Dd = diastolic diameter, Ps = systolic blood pressure, Pd = diastolic blood pressure, and P = blood density.Automatic QAS measurements were performed on the same common carotid arterial segments as those used for the quantitative IMT measurement, evaluating the modification of the arterial internal diameter between the systolic and diastolic phases as follows: Carotid arterial internal diameter waveforms were assessed using an ultrasound and converted to carotid arterial pressure waveforms using a derived exponential relationship between the pressure and arterial cross-sections; derived carotid arterial pressure waveform was calibrated to the brachial end-diastolic pressure and MAP by iteratively changing the wall rigidity coefficient . QAS wasFasting venous blood samples were collected in the morning after polysomnography from the antecubital vein, after at least 8 h of overnight fasting, and immediately centrifuged . Fasting triglycerides (TG), total cholesterol (TC), high- and low-density lipoprotein  were measured using a random-access chemistry analyzer . The remaining serum samples were cryopreserved at −80°C until further analysis. Chemerin and adiponectin serum concentrations were measured using commercially available ELISA kits  following the manufacturer's instructions. Apelin  and SFRP5  were also detected by ELISA kits. Intra-assay and inter-assay CVs were <10 and <12% for chemerin, 3 and 8.3% for adiponectin, <8 and <10% for apelin, and <10 and <12% for SFRP, respectively.t-test for normalized data and Mann-Whitney U-test for non-normalized data. All categorical variables were analyzed with Chi-square or Fisher's exact test, when appropriate. Correlation between two quantitative variables was assessed using the Pearson or Spearman coefficient. Stepwise models of multiple linear regression analyses were performed in order to assess the impact of independent variables on mean CCA parameters. Results were considered statistically significant if the p-value was <0.05.All statistical analyses were performed using the SPSS software version 20.0 for Windows . For the CCA parameters, we calculated the average of bilateral CCA before analysis. The distributions of quantitative variables were tested for normality using the Kolmogorov–Smirnov test and the QQ plot was used for vision tests. Normal data are presented as mean ± standard deviation (SD) and skewed data are described as median [interquartile range (IQR)]. The categorical variables are expressed as a number (percentage). The variables were compared between the non-snoring group and OSA group using an independent 2 was much more severe among OSA patients. The serum SFRP5 levels were significantly lower in OSA patients than the non-snoring participants. As for the CCA parameters, the quantitative IMT, stiffness coefficients (α and β) and PWV were significantly higher in the OSA patients than the non-snoring participants. CC and DC in OSA patients were significantly lower than those in non-snoring participants. There was no significant difference in the stiffness coefficients (α and β) between the two groups.The basic characteristics of the 95 subjects, consisting of 62 OSA patients and 33 non-snoring participants, were collected. As shown in 2 and adiponectin. As for DC, it was negatively correlated with age, the proportion of males, TG, AHI, and CT90% and positively correlated with mini SaO2 and adiponectin. The arterial stiffness coefficients, α and β, were both positively correlated with age, AHI, and CT90 and negatively correlated with mini SaO2. PWV was positively correlated with age, AHI, and CT90 and negatively related to mini SaO2 and levels of adiponectin.The correlations between quantitative IMT, arterial stiffness, and participants' characteristics are listed in As shown in 2 and CC, and between DC and sex/AHI; mini SaO2 was independently associated with arterial stiffness coefficients, α and β; and sex and mini SaO2 were independently associated with PWV  and arterial stiffness among OSA patients with standard polysomnographic data.However, the study has some limitations. First, the sample size was small. Therefore, the relationship between the adipocytokines and the severity of OSA could not be established. Second, as the insulin levels were not detected, the relationship between insulin resistance and IMT/arterial stiffness could not be assessed. Third, the waist/hip ratio was not measured and the only BMI criterion may inaccurately estimate the degree of overweight.2 were also independently associated with arterial stiffness. These results suggest that it is important to treat young OSA patients in order to reduce the risk for arterial stiffness, however, the role of adipocytokines requires further investigation.In conclusion, we found that the quantitative IMT and carotid arterial elasticity of OSA patients were significantly worse and that SFRP5 levels decreased significantly in OSA patients. Adiponectin correlated with arterial stiffness among OSA patients but the relationship disappeared after a multivariable adjustment. Furthermore, age is the main independent factor correlated with quantitative IMT and arterial stiffness and that AHI and mini SaOThe clinical data used to support the findings of this study are available from the corresponding authors upon request.The studies involving human participants were reviewed and approved by the Internal Review Board of the Institutional Ethics Committee of the Shanghai Jiao Tong University Affiliated Sixth Hospital. The patients/participants provided their written informed consent to participate in this study.FS and HY designed the study. JZ, ZS, and JC performed the collection and handling of the data. HX, YQ, and HZ analyzed the data and wrote the manuscript. JG and SL revised the manuscript. All authors discussed the data and accepted the final draft.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


The diagnosis of arterial hypertension based on measurements of blood pressure in the office has low accuracy.To evaluate the prevalence of masked hypertension (MH) and white-coat hypertension through home blood pressure monitoring (HBPM) in pre-hypertensive and stage 1 hypertensive patients.Retrospective study, of which sample consisted of individuals with BP ≥ 120/80 mmHg and < 160/100 mmHg at the medical office without the use of antihypertensive medication and who underwent exams on the HBPM platform by telemedicine (TeleMRPA) between May 2017 and September 2018. The four-day MRPA protocol was used, with 24 measurements, using automated, validated, calibrated equipment with a memory function.2. The casual BP was higher than the HBPM in 7.6 mmHg for systolic blood pressure (SBP) and 5.2 mmHg for diastolic blood pressure (DBP), both with statistical significance (p < 0.001). There were 558 (43.8%) normotensive individuals; 291 (22.9%) with sustained hypertension; 145 (11.4%) with MH and 279 (21.9%) with white-coat hypertension (WCH), with a diagnostic error by casual BP in the total sample in 424 (33.3%) patients. In stage 1 hypertensive individuals, the prevalence of WCH was 48.9%; in prehypertensive patients, the prevalence of MH was 20.6%.The sample consisted of 1,273 participants, of which 739 (58.1%) were women. The mean age was 52.4 ± 14.9 years, mean body mass index (BMI) 28.4 ± 5.1 kg/mMH and WCH have a high prevalence rate in the adult population; however, in prehypertensive or stage 1 hypertensive patients, the prevalence is higher. Out-of-office BP measurements in these subgroups should be performed whenever possible to prevent misdiagnosis. It is noteworthy that MH, WCH and AH are highly prevalent and are related to an increase in cardiovascular morbidity and mortality.4 Therefore, they should be investigated and diagnosed, and for this purpose, it is essential to use methods capable of monitoring BP outside the doctor's office environment.6In this context, considerations should be given to the possibility of normotension, masked hypertension (MH), white-coat hypertension (WCH), and sustained AH.7Ambulatory (ABPM) or home (HBPM) BP monitoring can be used for home BP measurement, with the latter offering the possibility of providing the necessary information for the appropriate diagnosis with greater comfort and better cost-benefit ratio.9Also, in relation to HBPM, the inclusion of the habitual BP measurements into the patient’s routine has shown an increase in compliance with drug treatment. This benefit seems to be even greater when using telemedicine platforms.7An adequate identification of MH and WCH is so important that the main guidelines of AH recommend the use of ABPM or HBPM in the diagnostic investigation whenever possible, emphasizing their use at the initial BP alterations.The present study is the first national study to evaluate the prevalence of MH and white coat hypertension through the HBPM in prehypertensive and stage 1 hypertensive patients.This study was submitted and approved by the Human Research Ethics Committee of Hospital das Clínicas da Universidade Federal de Goiás under CAEE number 99691018.7.0000.5078.www.telemrpa.com) from May 2017 to September 2018. Of the total, those who underwent the examination for diagnostic purposes and were not using antihypertensive drugs were selected.This is a retrospective study that evaluated the data of all patients who underwent exams on the TeleMRPA platform .1Inclusion criteria were age older than 18 years; individuals assessed on the TeleMRPA platform, without the use of antihypertensive drugs and who had, by the casual measure (mean of two measurements) performed at the clinic on the first day of the protocol, SBP and DBP that met the criteria for the diagnosis of prehypertension (PH) - SBP ≥ 120 mmHg and/or DBP ≥ 80 mmHg and SBP < 140 mmHg and DBP < 90 mmHg; or stage 1 AH - SBP ≥ 140 mmHg and/or DBP ≥ 90 mmHg and SBP < 160 mmHg and DBP < 100 mmHg, according to the Brazilian Guideline of Arterial Hypertension  and six measurements a day on four consecutive days (three in the morning and three in the evening), with a total of 24 measures to calculate the mean. This mean value is considered normal when lower than 135/85 mmHg  is instructed to measure the BP twice a day, following the abovementioned protocol.It is recommended, on the first day, when the patient receives the device at the health unit, that the patient be taught the correct handling of the BP measuring device, as well as the technique for adequate and reliable measurement. This recommendation follows the DBHA guidelines.Patient data, as well as BP values, were included into the TeleMRPA platform and analyzed for the following variables:Socio-demographic data: gender, age, sample distribution and BP behavior by geographic regions;2).Anthropometric data: BMI using the Quetelet formula (BMI = weight in kg/height in metersBlood pressure: mean BP at the clinic (first day), mean of home BP measures (second to fifth days) and mean BP in morning and evening, mean pulse pressure and BP variability.The database was created using the Excel® (Microsoft) software with data imported from the TeleMRPA platform; the numerical codes were typed by three researchers with subsequent cross-checking to identify and correct typing errors.t-test was used to compare BP measurements between the casual measurements and HBPM. To compare the frequencies of masked AH between stage 1 and stage 2 prehypertensive patients, the chi-square test was used, which was also used to compare the diagnoses of prehypertension and stage 1 hypertension between the casual BP measure and the HBPM. The significance level was set at p < 0.05. The Stata® software, version 14.0 was used for the analysis.Continuous variables were presented as mean and standard deviation and categorical variables as absolute and relative frequencies. The Kolmogorov-Smirnov test was used to verify the distribution of the continuous variables. The paired 2. As for gender, 739 (58.1%) were women.The initial sample consisted of 4,350 individuals who underwent HBPM from May 2017 to September 2018 in nine Brazilian states. Of these, 1,273 participants with a clinical diagnosis of prehypertension or stage 1 AH and without use of medications  were selThe mean values of casual BP were 133.2 ± 11 mmHg and 84.1 ± 8 mmHg, and for HBPM, the mean values were 125.5 ± 11.7 mmHg and 78.9 ± 8 mmHg for SBP and DBP, respectively. The mean number of valid measures was 22.96.When comparing the means of the casual BP with the HBPM, higher values were found for casual BP in 7.6 mmHg for SBP and 5.2 mmHg for DBP, both with statistical significance (p < 0.001) .Considering the casual BP measurement, 703 (55.2%) participants were classified as prehypertensive and 570 (44.8%) as stage 1 hypertensive. When we considered the measures of the HBPM for the diagnosis, in the total sample, 558 (43.8%) were normotensive; 291 (22.9%) had sustained hypertension; 145 (11.4%) had MH; and 279 (21.9%) had WCH; that is, in this population, 33.3% of the diagnoses by casual measurement were wrong.When analyzing only the prehypertensive group, there were 145 individuals (20.6%) who actually had masked hypertension, and if we separate those individuals with SBP ≥ 130 mmHg and < 140 mmHg, and/or DBP ≥ 85 mmHg and < 90 mmHg (n = 364), the prevalence of MH increases to 27.8% .In the stage 1 hypertensive group, 279 individuals (48.9%) with WCH were identified .The present study confirmed that the BP measurements obtained through HBPM is very useful in the diagnosis of AH phenotypes and allowed the reclassification of 33.3% of the assessed individuals, thus adding important information to the approach and follow-up of these individuals. We emphasize the significant number of individuals included in the study, from nine states of the five Brazilian geographic regions.11 It is also well established that BP monitoring methods outside the office, when compared to the casual measure, have a higher diagnostic accuracy and show a better prediction of cardiovascular risk.13AH is a highly prevalent disease in the adult population; in a worldwide survey of 1,128,635 individuals, the prevalence was 34.9%, most of them with stage 1 hypertension. It is also known that the prevalence of PH is at the same level, reinforcing the need for a correct diagnosis, so that the most appropriate conduct can be implemented.In the studied sample, when we compared the means of casual BP with HBPM, we found significantly lower means in HBPM, with statistically significant differences (p < 0.001) for both SBP and DBP.7Based on this scientific evidence, to avoid diagnostic error, the most recent AH guidelines have strongly recommended the use of ABPM or HBPM for diagnostic evaluation, especially in individuals with initial BP alterations.16When only those individuals with diagnostic criteria for PH or stage 1 AH were assessed, in which the chance of casual measures that induce misdiagnosis is higher, we found a prevalence of true normotension and hypertension of only 66.7%, that is, in 33,3% of the cases, the diagnosis would have been wrong, if we considered only the casual measure. These data coincide with other publications that found similar error rates.17 It is worth mentioning that this prevalence is high in adults, but it is also significant in adolescents.6The risk of WCH in stage 1 hypertensive patients is even more important, or MH in prehypertensive patients because, contrary to what was believed, both WCH and MH are associated with higher cardiovascular mortality and, in the specific case of MH, this mortality is even higher than that of patients with sustained hypertension.21 which dedicate special attention to prehypertensive individuals, since some of these individuals will show a significant increase in cardiovascular outcomes. It is also justifiable recommending the American and European guidelines regarding the performance of ABPM or HBPM whenever possible when casual BP is ≥ 130/85 mmHg.19In the sample of the present study, among the prehypertensive patients (n = 703), we found a prevalence of MH of 20.6%; this value is even higher when we analyze the highest BP strata in this group. In PH patients with SBP ≥130 mmHg and/or DBP ≥ 85 mmHg, this prevalence is 27.8%, significantly higher (p < 0.001) than PH patients with BP levels lower than 130/85 mmHg. Our findings are in agreement with the trend seen at the last guidelines and statements,Finally, when we evaluated the individuals diagnosed as stage 1 hypertension (n = 570), we found a prevalence of WCH of 48.9%, which could result in misdiagnosis and use of inadequate therapeutic strategies in almost half of these individuals.Most of this sample consisted of individuals from the Northeast region of the country (67.7%); this may be considered a limitation; however, as the analysis refers to AH phenotypes, it seems to us that the geographic region distribution would have little or no effect on the results.The Telemedicine MRPA (TeleMRPA) platform is an extremely useful, low-cost, easy-to-perform and wide-ranging modality, allowing a systematic evaluation of home-based BP measures, in accordance with the DBHA recommendations. In addition to the individual evaluation in clinical practice, the accumulation of information on this platform represents an important database for analyses on the diagnosis and treatment of AH in several regions of Brazil, both in public and private institutions.The casual BP measurement is a method used for AH screening, but it is necessary to take into account that home measurements are more accurate for the diagnosis.We found high prevalence rates of MH and white-coat hypertension in individuals diagnosed with prehypertension or stage-1 hypertension.The TeleMRPA platform allowed the reclassification of 33.3% of the assessed individuals.


At baseline, in univariate analysis, RHI in the CKD group correlated positively with eGFR  and correlated negatively with age , Charlson index , systolic blood pressure , and proteinuria . Reactive hyperemia index in the control group did not significantly differ from RHI observed in patients with CKD stages 1 to 5 . In adjusted analysis, only age  remained independently associated with RHI at baseline. During follow-up, 8 patients suffered a MACCEs, 33 patients experienced renal function deterioration, 17 patients were hospitalized for medical reasons and 6 patients died. RHI at baseline was not significantly associated with CKD progression , hospitalizations , and all-cause mortality  or MACCEs , but was significantly associated with cerebrovascular events  and with a composite cardiovascular outcome . Conclusion: Our results suggest that RHI may be a predictor for the development of cerebrovascular events in pre-dialysis CKD patients who may benefit from more aggressive preventive measures.Background: Patients with chronic kidney disease (CKD) have markedly increased rates of end stage renal disease, major adverse cardiovascular/cerebrovascular events (MACCEs), and mortality. Endothelial dysfunction (ED) is an early marker of atherosclerosis that is emerging as an increasingly important non-traditional cardiovascular risk factor in CKD. There is a lack of clinical studies examining the association between ED and both cardiovascular and renal endpoints in patients with CKD. Aims: We examined the association between reactive hyperemia index (RHI), a validated measure of endothelial function measured by peripheral arterial tonometry (PAT), with traditional cardiovascular risk factors in pre-dialysis CKD patients and prospectively evaluated the role of RHI as predictor of renal and cardiovascular outcomes in this population. Methods: One hundred and twenty pre-dialysis patients with CKD stages 1 to 5 (CKD group) and 18 healthy kidney donor candidates (control group) were recruited and had a successful RHI measurement by PAT. General demographic and clinical information including traditional cardiovascular risk factors were registered from all participants. Thereafter, patients were prospectively followed-up for a median time of 47 (IQR 19–66) months to determine associations of RHI with renal outcomes, MACCEs, hospitalizations or mortality. Results: In the CKD patient population, the mean age was 57.7 ± 15.5 years, the mean eGFR was 54.9 ± 36.7 mL/min/1.73 m Chronic kidney disease (CKD) is one of the strongest risk factors for cardiovascular (CV) morbidity and mortality. Increased CV risk is observed even in the earlier stages of CKD and increases markedly as CKD progresses .Indeed, a CKD patient is more likely to die from CV disease than to progress to end-stage renal disease . BecauseEndothelial dysfunction (ED), one of the first steps in the development and progression of atherosclerosis, is considered a non-traditional CV risk factor in CKD and its prevalence progressively increases as the disease progresses to end stage kidney disease. ED is evident at an early stage in CKD patients, occurs independently of hypertension development and contributes to arterial stiffness and to renal interstitial fibrosis ,6,7.In addition to chronic inflammation and oxidative stress, hemodynamic disturbances, and the continuous exposure to uremic toxins in CKD, may result in an imbalance between endothelial injury and repair that progressively worsens as renal function deteriorates .The assessment of ED was found to be useful to predict cardiovascular events, not only in the general population but also in high-risk groups ,10. Fore2 and evidence of kidney damage; stage 2: between 60–89 mL/min/1.73 m2 and evidence of kidney damage; stage 3a: between 45–59 mL/min/1.73 m2 stage 3b: between 30–44 mL/min/1.73 m2; stage 4: between 15–29 mL/min/1.73 m2; stage 5: <15 mL/min/1.73 m2).We recruited pre-dialysis CKD patients, followed-up at the outpatient clinic of the Nephrology Dept. of São João University Hospital Center, Porto, Portugal. Patients were studied in standard conditions . Patients with acute kidney injury, ongoing immunosuppression, recent hospital admission (<2 weeks), recent infections (<1 week), heart failure (diagnosed according to appropriate Framingham criteria) and known psychiatric disturbances were excluded from the study. The etiology of CKD was registered, and patients were distributed according to KDIGO CKD categories, using GFR estimated by CKD-EPI formula , and a validated comorbidity index (Charlson Index) were assessed in both pre-dialysis CKD and control groups. Blood and urine samples were collected in all participants. Blood pressure was measured in the office at room temperature of 20–22 °C, with low light, no distractions, in the seated position, after at least 10 to 15 min of rest. Hypertension was diagnosed if systolic blood pressure (SBP) in the office was ≥140 mm Hg and/or diastolic blood pressure (DBP) was ≥90 mm Hg following repeated examination, or when patients presented controlled blood pressure values under anti-hypertensive pharmacologic treatment. Renal function (eGFR), proteinuria, phosphate (Pi), parathormone (iPTH), C reactive protein (CRP) and natriuretic peptide type B (BNP) serum levels were evaluated in all patients using standard laboratory methods. In addition, endothelial function was assessed by peripheral arterial tone (PAT) . This device allows non-invasive measurement of vasoreactivity without the disadvantages of conventional ultrasound measurement. The PAT serves as a measure of peripheral vasomotor function as was validated in the large, community-based Framingham study . Lower RAll recruited CKD patients were prospectively followed-up for a median of 47 (IQR 19–66) months, to evaluate hard renal and CV outcomes including progression of CKD and ESRD, hospitalizations, MACCEs and CV/all-cause mortality. The MACCEs included acute coronary syndrome (ACS), heart failure, and stroke.Acute coronary syndrome (ACS) was defined as a clinical diagnosis of ST-segment elevation myocardial infarction (STEMI), non-STEMI, or unstable angina pectoris. Heart failure was diagnosed when the patient met the appropriate Framingham criteria . CardiovU test or T test for independent samples, while chi-square tests were used to analyze differences in categorical variables. A Dunnet post hoc test was used to compare different CKD stages and the control group. A correlation analysis was performed using Spearman correlation coefficients. Linear regression was applied to determine the relationship between RHI and renal function adjusted for possible confounders. Coefficient regression (beta) and 95% confidence intervals (95% CI) are presented. All reported p-values were two-sided, and the significance level was set at 5%. All analyses were conducted using SPSS software .Categorical variables were described through absolute (n) and relative (%) frequencies, while continuous variables were described as mean and standard deviation, or median, interquartile (IQR) range, and minimum and maximum, when appropriate. Differences in continuous variables were assessed by Mann–Whitney The research was approved by the Ethics Committee for Health and the Local Institutional Review Board of São João University Hospital Centre and was carried out in accordance with the Declaration of Helsinki (2008) of the World Medical Association.One hundred and twenty patients  and 18 healthy volunteers , were enrolled in the study.2 (p = 0.006), a higher Charlson index: 3.9 ± 2.9 vs. 0.6 ± 0.6 (p < 0.001) and as expected, a lower eGFR: 54.9 ± 36.7 vs. 111.9 ± 11.2 mL/min/1.73 m2 (p < 0.001) compared with the control group. The leading etiologies of CKD in the pre-dialysis patient group were undetermined (13%) and diabetic nephropathy (11.6%). Hypertension, dyslipidemia, diabetes and cardiovascular disease were present in 80%, 57%, 30%, and 27% of the CKD patients, respectively. In the CKD group, 48% and 67% of the patients were treated with ACEi and statins respectively. The characterization of the control group and the pre-dialysis CKD population according to KDIGO stages is presented in p = 0.493). However, in the pre-dialysis CKD group RHI was significantly lower in patients with CKD stages 4  and 5 , in comparison with RHI observed in patients included in CKD stage 1 (p < 0.001) (p = 0.043). In addition, RHI was negatively correlated with age , Charlson index , systolic blood pressure , proteinuria , triglycerides , parathormone , and BNP  (p = 0.002), diabetes , dyslipidemia , cardiovascular , cerebrovascular disease  as well as those treated with statins  presented significantly lower RHI : 28.4 ± 5.9 vs. 25.3 ± 2.8 kg/m stage 1  i.e., th< 0.001) . RHI was= 0.001) . Pre-diaower RHI .p = 0.047) and hypertension  remained independent predictors for RHI in this setting. However, when age was included in the analysis, this relation was no longer observed , ESRD , hospitalizations , all-cause mortality  or MACCEs . However, RHI was significantly associated with cerebrovascular events  as well as with the composite cardiovascular outcome   months. During follow-up, 8 patients suffered a MACCE , 33 patients experienced renal function deterioration, of which 17 started dialysis. Seventeen patients were hospitalized for medical reasons and 6 patients died. In 3 out of the 6 patients who died, a MACCE was the main cause of death. Twenty-one patients reached the combined cardiovascular outcome . We then= 0.035) . None ofThe present study assessed endothelial function by RHI-PAT in a non-dialysis CKD population and in healthy subjects and explored the association of RHI with general CV risk factors as well as the predictive role of RHI regarding renal and cardiovascular outcomes in the CKD population, prospectively followed-up for approximately four years. The main findings were the following: (i) Although RHI was significantly lower in patients with CKD stages 4 and 5 compared with patients with CKD stages 1, in healthy subjects RHI did not differ significantly from the observed in non-dialysis CKD population; (ii) using multivariate logistic regression analysis, RHI-PAT was not related with most general CV risk factors in CKD patients, although a significant association was found with both eGFR and hypertension when age was not included in the analysis; (iii) during a mean follow-up period of 47 months of the non-dialysis CKD population, RHI-PAT at baseline was a predictor of cerebrovascular events as well as of the composite of CV outcome. Taken together, our results indicate that ED, non-invasively assessed by RHI-PAT, may provide information for CV risk stratification in this population, identifying patients vulnerable to cerebrovascular events during follow-up.Chronic kidney disease is associated with abnormalities of vascular function (including ED) that have been implicated in the disproportionately high CV morbidity and mortality in this population. A number of disturbances have been suggested to contribute to ED in CKD including elevated blood pressure, insulin resistance, abnormalities in the nitric oxide pathway (ADMA and L-arginine), inflammation (sVCAM-1 and sE-selectin), thrombosis (vWF), and endothelial dependent dilation (FMD) ,19. HoweThe lack of association of RHI-PAT with both CV risk factors and eGFR might be related to the role played by nitric oxide in the regulation of the digital hyperemia response. Actually, evidence has been gathered that the inhibition of nitric oxide synthesis completely abolishes FMD whereas it only reduces by 50% the digital hyperemia response ,24. One In the present study, age proved to be the independent predictor of RHI in the stepwise regression analysis. Our results fit well with the findings from the Brazilian Longitudinal Study of Adult Health cohort study that reported a negative association between age and RHI .We must emphasize, however, that older patients are highly prevalent in advanced CKD stages and are more prone to hypertension, which can underestimate the real influence of renal dysfunction and blood pressure on RHI. A previous study evaluated the effect of aging on microvascular reactivity in patients with advanced CKD . The autThe lack of association of RHI with general CV risk factors and eGFR in age-adjusted analysis in our study does not exclude the possibility that RHI may be useful to predict CV outcomes in these patients as was found in other populations ,28,29, aHirata et al., demonstrated that peripheral ED assessed by RHI correlated significantly with the presence of coronary artery disease in stable CKD patients and independently predicted cardiovascular event risk in these CKD patients . It shouWe acknowledge some limitations of our study. First, this was a single center observational study with a small number of patients and events, so we cannot demonstrate a direct cause-and-effect risk association. Confirmation by larger prospective investigations is required. Second, RHI was measured at a single time point at baseline and so we could not capture changes in RHI with the decrease of renal function. Third, the fact that CKD groups had different mean ages prevents us from unequivocally assuming that endothelial dysfunction decline is dependent of renal function deterioration. Nevertheless, we also emphasize that epidemiologically older patients are more prevalent in advanced CKD stages, and this is a hard limitation to overcome. Our study also has some strengths. To our knowledge this is the first study that evaluated prospectively the role of RHI-PAT as a predictor of renal and cardiovascular outcomes in a general non-dialysis CKD patient population. We were also able to compare RHI between patients with CKD and healthy controls.In conclusion, our results demonstrate that RHI, measured by PAT, declined with renal function but this association is age-dependent and there was no difference between the general non-dialysis CKD population and healthy subjects. Our findings also suggest that RHI may be a predictor for the development of cerebrovascular events in pre-dialysis CKD patients who may thus benefit from more aggressive preventive measures.


Brazil’s Family Health Strategy (FHS) leads public health policies and actions regarding community health, addressing arterial hypertension (AH) in primary care settings. In this scenario, the use of communication technologies becomes appropriate for the monitoring of patients with AH. To preliminary verify the intervention approach and the effects of using an m-Health application on the health conditions of patients with AH for a future study, we conducted a non-randomized, controlled, non-blind trial (N = 39), comparing the use of a mobile health app  with conventional AH monitoring over 3 months. During the study, we promoted health information workshops to engage patients from both intervention and control groups. Pre and post-intervention, we compared measurements of systolic and diastolic blood pressure; food frequency questionnaire; Appraisal of Self-Care Agency Scale; blood tests of hemogram, creatinine, uric acid, sodium, potassium, lipid profile, and glycemia. Improvements were identified in both groups due to the workshops, including the reduction in total and non-HDL cholesterol, healthier consumption of salads and sugary drinks, and increased self-care scores. Exclusively in the intervention group, which used the m-Health app, there was a change in systolic and diastolic pressure towards more adequate levels. In addition, the intervention group had improved levels of glucose and HDL cholesterol and reduced consumption of ultra-processed foods. In conclusion, the use of an m-Health app had positive effects on the health conditions of patients with AH under treatment within FHS, especially when combined with health information. On the context of FHS, the use of technology is encouraging supporting better health conditions. Among the AH modifiable factors, either by medication or by altering habits and behavior, there is obesity, sedentary lifestyle, eating habits, and stress. Controlling blood pressure can still be a challenge since, with everyday activities and lack of time, many people do not bother to maintain their normal blood pressure levels2. Among the main non-medicinal recommendations that should be followed, there are healthy eating, physical activity, reduction of sodium and alcohol consumption, and non-consumption of tobacco3.Arterial hypertension (AH) is one of the main modifiable risk factors for diseases of the circulatory system. With a high prevalence, AH is considered one of the most important public health problems. The World Health Organization estimates that about 600 million people have AH and, annually, 7.1 million individuals die from this disease, substantially burdening health systems4. The members of FHS health teams provide primary care for a defined number of families in an attached territory5. Organizing their actions and work plan, each FHS arrange the monitoring of patients with AH through periodic appointments, scheduled with a medical doctor or a nurse. These visits include the measurements of weight and blood pressure, along with treatment guidelines, and prescription of medications to promote the monitoring and evaluation of the treatment’s progress6.In Brazil, the units of Family Health Strategie (FHS) lead public health policies and actions with education, promotion, prevention, recovery, rehabilitation, and maintenance of community health7. When applied to hypertension treatment, these applications are promising in leading to a significant decrease in blood pressure levels, as well as an effective self-management tool of the disease10 and improving patients lifestyle11.The use of communication technologies becomes appropriate for the monitoring of patients with AH, since there is a need for solutions that improve the quality of care, which may also contribute to the coverage of treatment and educational actions. Among these technologies, there are mobile health applications , the practice of medicine supported by mobile deviceset al.12 developed the first version of the e-Lifestyle app and evaluated only patient engagement with the app, which aims to promote healthy habits in AH patients. This app includes features for logging and monitoring measurements of health conditions and habits, such as blood pressure, anthropometric measurements, sleep, and mood. Later, Biduski et al.13 evaluated the long-term user experience of patients using the app for 3 months, including aspects of the evolution between before, during and after usage. The project was then selected by the Ministry of Health of Brazil for its further development within the National Health System. Therefore, the purpose of this study was to evaluate the feasibility of the approach with a view on preparing the protocol for the definitive trial that will verify the effects of using the app on the health conditions of patients with AH in the public health network.In the m-Health scenario, Cechetti 14.We conducted a non-randomized, controlled, non-blind clinical trial comparing the use of an m-Health app with conventional AH monitoring over 3 months. A total of 45 volunteer participants (of whom 39 completed the study) were recruited, adults and elderly, men and women aged 19 to 77 years ;have a smartphone with Android Operating System version 5 or higher (for Intervention Group);have Internet access on a smartphone through Wi-Fi or mobile data (for Intervention Group).The criteria for participation in the research were:The data collection of this study occurred in three moments: pre-intervention, intervention, and post-intervention.15, we collected the following data before the intervention with all participants:After checking the inclusion criteria and applying the MMSE psychometric testI. Characterization questionnaire, with sociodemographic variables of gender, age, marital status, education, profession, and income. In addition, each participant was asked if he/she understood the meaning of the blood pressure measurement, how often he/she checked his blood pressure, and whether he/she recorded monitoring measurements frequently.II. Last week’s Food Frequency Questionnaire (FFQ), according to the model of the Food and Nutrition Surveillance System - SISVAN, prepared by the Ministry of Health in Brazil16.III. Appraisal of Self-Care Agency Scale-ASA-A17.IV. Blood tests of hemogram, creatinine, uric acid, sodium, potassium, total cholesterol, HDL, triglycerides, and glycemia. A trained professional from our university laboratory collected the blood samples.V. Measurement of systolic blood pressure and diastolic blood pressure.The allocation of patients in each group was based on the eligibility criteria. For instance, if the patient met all the criteria but did not have a mobile phone compatible with the app, then he or she would be allocated to the Control Group. If the patient had a mobile phone compatible with the app, he or she would be allocated to the Intervention Group.The sample was stratified into two groups. The Intervention Group (IG) had 23 participants who completed the intervention using the e-Lifestyle app. The Control Group (CG) had 16 participants and did not have intervention with the app during the study. Blood pressure measurements from IG were read through the data registered on the application, which could be followed by the health professional via the web. For the GC, the measurements were recorded on paper and collected at each meeting. All participants were taking hypertension drugs such as hydrochlorothiazide, losartan, captopril, enalapril or atenolol. During the intervention, no dosage or drug was changed; therefore, the participants continued with their usual treatment.Usually, health education workshops are one of the FHS strategies, which are conducted in support groups for patients with chronic diseases on a monthly or less frequent basis. For this study, workshops were conducted more frequently. Every 15 days during the intervention, participants from both groups attended scheduled workshops at the FHS health unit to receive nutritional guidance and information about health habits from dietitians and nurses. The workshops took place in the form of lectures and talks, always performed by the same professionals in a standardized way. At those meetings, the participants also had their blood pressure values and other anthropometric data measured.We instructed CG participants to measure their blood pressure during the 3 months of the intervention period, storing the information as they usually did before, according to their conventional monitoring. Thus, all participants made notes on paper and brought us in the meetings. On average, participants measured blood pressure once a day during the period.First, IG participants had the e-Lifestyle app Fig.  installeet al.16, this period is suitable to accomplish possible significant changes in blood pressure levels through weight loss and balanced diet, along with other healthy habits. The app has elements that aim to engage patients in their own treatment, as demonstrated by Cechetti et al.12. It allows the recording of variables related to blood pressure, weight, waist circumference, height, sleep, mood, and the practice of physical activities. Other features include risk assessment, recommendations based on reference values, alerts and reminders. The app has a dashboard designed so that the patient has on one screen the summary of their most important health conditions. In-app patient data is stored in a computational cloud for integration with a web dashboard, which allows a FHS’ healthcare professional to remotely monitor the patient.The IG participants used the e-Lifestyle app for 3 months. According to Neumann After 3 months of intervention, we collected the following data again:17.I. Last week’s Food Frequency Questionnaire (FFQ), according to the model of the Food and Nutrition Surveillance System - SISVAN, prepared by the Ministry of Health in Brazil18.II. Appraisal of Self-Care Agency Scale-ASA-AIII. Blood tests of hemogram, creatinine, uric acid, sodium, potassium, total cholesterol, HDL, triglycerides, and glycemia. A trained professional from our university laboratory collected the blood samples using the same technique as in the pre-intervention.IV. Measurement of systolic blood pressure and diastolic blood pressure.Quantitative data were analyzed using the statistical package SPSS 22.0 (IBM Corporation). We used the Wilcoxon (paired) or Mann Whitney (independent) test to compare the means, since the variables did not show normal distribution by the Kolmogorov-Smirnov and Shapiro-Wilk test. Thus, the Wilcoxon test was used for the comparison between the pre- and post-intervention values of the blood tests, FFQ, and ASA-A. For the ASA-A scores, we also applied the Mann Whitney test to compare the self-care score between the groups before and after the intervention. The same test was used to compare diastolic and systolic blood pressure measurements between the pre and post-intervention groups. A significance level of 5% was considered for all analyzes.To verify the factors associated with the app use, we performed logistic regression of the data collected pre and post intervention. The dependent variable considered the base category “did not use the app” (CG) and the interest category “used the app” (IG). We related the dependent variable with the independent variables of interest, which are: gender (categorized), age (continuous), level of education (categorized), pre/post ASA-A self-care score (continuous), pre/post systolic blood pressure (continuous), and pre/post diastolic blood pressure (continuous).During the evaluation, 45 participants were recruited. However, 6 dropped out before the end of the study Fig. . Among tTable Regarding income, data showed that about 80% of the participants had some kind of income, independent of the group. The sample was composed mostly of workers and retirees. When participants were asked about understanding the meaning of blood pressure measurement, most said they did understand it. As for the frequency of blood pressure measurement, most said they measured only once a month and did not record their data for further evaluation.Comparing the results of blood tests before and after the intervention Table , IG loweRegarding food consumption Table , IG incrSelf-care data Table , showed In the comparison of blood pressure measurements Table , there wIn the pre-intervention data analysis using the multiple logistic regression model, no variables were associated with app use . In the analysis of post-intervention data using the multiple logistic regression model, the only variable associated with the use of the application was the post-intervention systolic blood pressure , adjusted for other variables .Overall, there were beneficial effects verified in the several variables measured, even in the control group, which we did not originally foresee. We realize that intensifying health education workshops had substantial prospects in the context of the FHS and this is worthy of being investigated in future studies. However, it restricts our main objective, which is to verify what is exclusively app’s effects. Hence, from the point of view of feasibility, we concluded from this pilot that the definitive trial cannot provide additional workshops. Besides, the sample size will be recalculated and substantiated with a propensity score that will consider the effects pre-verified in this pilot towards a better balance. Meanwhile, the evaluation of many outcome variables becomes a complex task for correlating all the findings, hindering the establishment of solid conclusions. Therefore, the definitive trial will focus on systolic and diastolic blood pressure as the primary outcome, considering that these are the main reference parameter in the AH treatment. Nevertheless, secondary studies should address the other variables tested in this pilot.6. Socioeconomic status and education appear as risk factors for chronic noncommunicable diseases and cardiovascular diseases6. Health professionals should encourage measures that impact lifestyle, but their adoption falls to the patient’s understanding of his/her own problem, to the motivations and conditions associated with the treatment. In this sense, income and education, as social determinants of health, are closely related to hypertension19. During the study, all patients had regular access to a doctor at the FHS, following their exams and clinical picture. Furthermore, participants from both groups had the assistance of a collaborative team of professionals. However, these results do not allow generalization and can only be interpreted from the results of the definitive clinical trial.In relation to the demographic and socioeconomic characteristics, the profile found in this research resembled surveys performed in similar scenarios, concluding that the majority of participants are workers or retirees living in the area covered by the FHS20. Total cholesterol decreased in both groups, with a more significant improvement for IG. Non-HDL cholesterol had lower levels in both groups, especially the significant improvement in IG, highlighting the positive effects of the app. The HDL cholesterol had a significant difference only for IG. The adequate diet associated with the practice of regular physical exercises may have contributed to the results found, probably motivated by the use of the app with its features of weight and BMI monitoring. Overall, cholesterol showed significant improvements, unlike triglycerides, which require a longer period of dietary reeducation and healthy habits to achieve more considerable changes21.Regarding the blood tests performed, there was a significant change in the glucose levels in the IG. This attribution is mainly due to the comorbidity of AH and Diabetes Mellitus (DM), common in adult and elderly populationset al.22 report that the lipid profile of patients with hypertension is commonly worse than patients with normal blood pressure. The improvement in the lipid profile is an remarkable result, considering that more than half of the decrease in cardiovascular mortality has been attributed to changes in risk factors in the population, especially the lower levels of cholesterol, blood pressure and smoking23. Similar studies — addressing body weight, waist measurement, blood pressure, and lipid profile — showed improvements in lipid levels with the use health information technology25.Sarkar 26 details this as one of the outstanding improvements provided by strategies such as empowering patients through mechanisms such as education and self-monitoring of blood pressure, including the use of technology to provide reminders and encouragement. Healthy dietary behavior, as a modifiable factor of cardiovascular disease, is crucial for the prevention and early intervention in AH27.The increase in the consumption of salads was evidenced in both groups. This result and other positive changes in eating habits may have occurred because the sample was exposed to the dietitian’s guidance during the intervention period. However, it is not ruled out that the results could be enhanced by the use of the app in the IG, nor that the app could produce effects without being associated with the guidance from dietitians. Whelton28. These are also substantial improvements, given the difficulties encountered by patients in maintaining a healthy diet. The official food recommendations in Brazil define that the food base should be fresh, and ultra-processed foods should be avoided32.Both groups decreased sugary drinks consumption. In addition, the IG exclusively significantly decreased in the consumption of processed meat products (p = 0.018) and filled biscuits (p = 0.002). Those are industrialized foods, rich in sodium and saturated fats, which may raise cholesterol levels that influence AH33. Because the interactive support tool encourages patient’s self-registration of variables related to health and provides feedback on changes, patient engagement is augmented35. Registering daily health data on an app can motivate the patient to create a routine, paying more attention to their health by improving adherence to treatment36. In this sense, we can assume that using the app has positively influenced the patient’s commitment to medication intake and, consequently, has influenced with better outcomes in the IG.The self-care scale assessment (ASA-A) revealed improvements for both groups, probably due to FHS monitoring with regular feedback and health care. This suggests that the app was a kind of incentive for care, but also that the health education workshops provided had a positive influence on these values. These results also underline the valuable role of health education provided by professionals in the context of FHS. The app’s features of reminders, sleep, mood, physical activity, and food information become attractive for a healthier lifestyle and improvement on several factors of self-care and self-management37. Therefore, the present study corroborates similar results in the literature41, reaffirming the many benefits of using m-Health technology to treat AH.Finally, the most important result of this study was the improvement in systolic and diastolic pressure levels observed in IG. Both values shifted towards healthier reference standards  defined by Brazilian guidelines42. With the FHS actions, patients participate as actors in the construction of knowledge and practices that aim to favor health conditions and, consequently, patients can achieve independence in the decision-making process, with new possibilities to improve lifestyle43. In the context of FHS and primary care, digital technologies can assuage health care discrepancy, enabling the provision of integrated information on disease management, especially hypertension46. Using m-Health technologies represents an attractive option to improve health behaviors and outcomes given the widespread use of these technologies49. Feedback, workshops, and primary care offered by the FHS can be enhanced by using m-Health. All the positive consequences reassure the advantages of using technology and its relevant impact on the public health context by lowering costs and improving the quality of care52.Giving feedback and orientation to the population is one of the strategies organized by the FHS to promote health, which includes guidance on healthy eating, regular physical activity, group activities with seniors, workshops and lectures on hypertension and diabetesThere are some limitations in the study; among them, the difficulty of adherence to the use of the app. Over the 3 months, users needed to be encouraged with workshops and live feedback so they could handle the app’s features. Consequently, withdrawals and the lack of knowledge about research participation made it difficult to recruit patients for the study. Although the workshops showed good results in adherence and continuance in the study, they may have interfered with the outcomes, making the interpretation of the findings difficult. Regarding the study design, non-randomization may have had a bias influence on the findings, as well as the difference of 7 participants between groups. However, the two groups were similar concerning the demographic and socioeconomic aspects, minimizing the possible biases. Besides, the impossibility of blinding health professionals and interviewers may have contributed to the information bias. Nevertheless, all those involved in the research underwent training to lessen the possibility of bias.14 using a new improved and comprehensive app’s version.In this pilot study, we aimed to preliminarily validate the intervention and assessment method and clinical effects of the e-Lifestyle app. The version used does not yet include all the factors necessary for the treatment of AH. Even so, the outcomes are encouraging: there is evidence that using an app can have beneficial effects on the health conditions of patients with AH. The use of technologies combined with health information is a positive development that can contribute to the therapeutic scheme of patients with hypertension, providing greater adherence to treatment, healthier habits, and better health conditions. Improvements were identified in both groups due to the health education workshops. However, the intervention group, which used the m-Health app, performed better. Even though the app combined with the workshops of FHS has the potential for more positive outcomes, this needs to be confirmed in further studies with a suitable technique. From the results, we could understand the benefit and association of each app feature with health outcomes. We concluded that the first goal, to be met in the definitive clinical trial, is to verify what is exclusively the effect of the app on FHS patients. With this determination, other studies will then be able to verify the best way of delivering or associating app intervention. Accordingly, we better adjusted the intervention technique, the expected outcomes, and the assessment frameworks to create the definitive trial’s protocol


Type 2 diabetes mellitus (T2DM) represents the main cause of chronic kidney disease (CKD) and end-stage renal disease (ESKD), and diabetic kidney disease (DKD) is a major cause of morbidity and mortality in diabetes. Despite advances in the nephroprotective treatment of T2DM, DKD remains the most common complication, driving the need for renal replacement therapies (RRT) worldwide, and its incidence is increasing. Until recently, prevention of DKD progression was based around strict blood pressure (BP) control, using renin–angiotensin system blockers that simultaneously reduce BP and proteinuria, adequate glycemic control and control of cardiovascular risk factors. Glucagon-like peptide-1 receptor agonists (GLP-1RA) are a new class of anti-hyperglycemic drugs shown to improve cardiovascular and renal events in DKD. In this regard, GLP-1RA offer the potential for adequate glycemic control in multiple stages of DKD without an increased risk of hypoglycemia, preventing the onset of macroalbuminuria and slowing the decline of glomerular filtration rate (GFR) in diabetic patients, also bringing additional benefit in weight reduction, cardiovascular and other kidney outcomes. Results from ongoing trials are pending to assess the impact of GLP-1RA treatments on primary kidney endpoints in DKD. In several contemporary studies, 28% to 43% of patients with T2DM have CKD, defined as either a glomerular filtration rate (GFR) below 60 mL/min/1.73 mDiabetic kidney disease (DKD) is a leading cause of morbidity and mortality in diabetes. CKD is associated with all-cause and cardiovascular mortality in patients with diabetes. Indeed, the excess mortality of diabetes occurs mainly in individuals with diabetes and proteinuria and stems not only from end-stage renal disease (ESRD) but also from cardiovascular disease. As such, DKD is on track to surpass all other diabetic complications in terms of attributable morbidity and mortality . Indeed,In recent years it has become apparent that diabetes-associated CKD is more heterogeneous than previously thought, and may consist predominantly of tubular, interstitial and/or vascular involvement rather than glomerular injury. Thus, patients with decreased GFR may not have pathological albuminuria, and the term DKD is now preferred, leaving the term diabetic nephropathy for histologically confirmed lesions . DespiteUntil recently, prevention of DKD progression was based on strict blood pressure (BP) control, using renin–angiotensin system blockers that simultaneously reduce BP and proteinuria, adequate glycemic control and control of cardiovascular risk factors , as well as nephrotoxic drug avoidance ,8,9 Tab. This apBP should be controlled with drugs that reduce cardiovascular events  . HoweverOptimizing glucose control in DKD patients is challenging due to an increased risk of adverse effects from certain glucose-lowering agents. Both UKPDS and DCCT have clearly demonstrated that progression of retinopathy and nephropathy is linked to glycemic control and it is crucial that patients maintain HbA1c levels less than or equal to 6.5% to minimize disease progression . Neverth2. It should be noted that this limit is driven by the perceived lack of benefit on glucose control at these low eGFR levels, since the mechanism of antihyperglycemic action depends on glycosuria. Nevertheless, recent trials demonstrated nephroprotection in patients with GFR >30 mL/min/1.73 m2, even when the drug was maintained until the initiation of dialysis [2.Among the agents used to treat hyperglycemia, only sodium–glucose co-transporter type 2 inhibitors (SGLT2i) and certain GLP-1RA have been shown to improve kidney outcomes regardless of glycemic control . SGLT2i dialysis ,18. Somedialysis , semagludialysis  and duladialysis , have alThe prevalence of obesity and abdominal obesity in T2DM patients remains high. In Spain, the country projected to have the longest life expectancy by 2040, this prevalence is 50% and 68%, respectively . Obesity2 and albuminuria > 30 mg/g), the combination of a hypocaloric diet and physical exercise was associated with 12% weight and 36% albuminuria reduction, accompanied by improved renal function and glycemic control [p < 0.001). The beneficial impact was more evident in patients with pathological albuminuria [In T2DM patients with obesity and advanced CKD  and glucagon-like peptide-1 (GLP-1). Two incretin hormones have been identified produced by entero-endocrine K cells, whereas GLP-1 is mainly secreted from L cells located throughout the intestine, more abundantly towards the distal ileum and colon. GLP-1 acts through binding to its receptor (GLP-1R) triggering a downstream signaling cascade. GLP-1R is a class B G protein-coupled receptor not only expressed in the pancreas and central nervous system, but also detected in lower levels in the gut, kidneys, lungs, liver, heart, muscle, peripheral nervous system and other tissues. GLP-1 increases insulin secretion in response to nutrients, particularly glucose  and suppresses glucagon secretion from pancreatic islet cells, with a reduction in postprandial glucose levels as the net result . GLP-1 seems also to play a role in the central regulation of feeding by increasing satiety signals and reducing appetite, resulting in decreased food intake and subsequent weight loss. Further, GLP-1 exerts effects on the gastrointestinal tract by slowing the gastric emptying rate and small intestine peristalsis, which conditions slower absorption of glucose. Depending on the molecule (native or recombinant long-acting) and administration route, GLP-1RA have broad pleiotropic action on metabolism. All these actions are transduced by a single GLP-1R located in many organs including the kidney. Among the numerous beneficial effects mediated by GLP-1RA are blood glucose regulation, body weight reduction due to food intake inhibition and reduced gastric motility, cell proliferation stimulation, inflammation and apoptosis reduction, and improved cardiovascular function, neuroprotection and renoprotection ,29. In T2DM individuals, circulating GLP-1 levels are similar to those found in normoglycemic individuals, yet partial resistance to the insulinotropic effects of GLP-1RA is seen in some T2DM patients at physiological and pharmacological concentrations.GLP-1 response to oral glucose tolerance test is up to 25% lower in individuals with prediabetes or T2DM than in those with normal glucose regulation. Whether a defective incretin system in T2DM is caused by decreased responsiveness of β cells to GLP-1 and glucose-dependent insulinotropic polypeptide (GIP), or by hyposecretion of incretin hormones, remains unclear. Importantly, in T2DM the insulinotropic response to exogenous GIP administration is completely lost, while a partially preserved, substantial dose-dependent response to GLP-1 is observed . Diminished insulin secretion in response to treatment with GLP-1RA has been associated with genetic and metabolic alterations, thus implicating genetic variation in the transcription factor 7-like 2 (TCF7L2), the loci for GLP-1R, wolfram syndrome 1 and chymotrypsinogen B1/2 . ImpaireGLP-1RA are a pharmacological family of peptides that stimulate the human GLP-1 receptor. They can be classified according to different characteristics, such as molecular size, chemical structure and duration of action. Based on their chemical structure, GLP-1 RA can be divided into two groups: incretin-mimetics  and human GLP-1RA. Incretin-mimetics are derived from exendin-4, a 39 amino acid peptide isolated from the saliva of the giant lizard Gila monster (Heloderma suspectum), and they share a 53% homology with human GLP-1. Such structural differences with human GLP-1 confer both exendin-4 and incretin-mimetics with resistance to inactivation by DPP-4. Currently, daily exenatide, once-weekly exenatide and lixisenatide are approved exendin-4 analogs, and efpeglenatide is an investigational drug in Phase 3 clinical development. Incretin-mimetic drugs are mainly eliminated by glomerular filtration, tubular reabsorption and subsequent proteolytic degradation, so their clearance is reduced in patients with renal insufficiency. Due to their partial homology to human GLP-1, these drugs may induce an immune response in some individuals; approximately 2–3% of patients develop inactivating antibodies. Human GLP-1 analogs show a close structural homology to native GLP-1, and they increase their half-life through several molecular modifications, such as attachment of fatty acid (liraglutide and semaglutide), albumin  or a constant fraction of immunoglobulin G4 (dulaglutide). Single substitutions of amino acids in the molecular sequence of native GLP-1 confer human GLP-1RA resistance to DPP-4 cleavage. Liraglutide, dulaglutide and semaglutide  are currently approved human GLP-1RA, since albiglutide was withdrawn from the market for commercial reasons. Human GLP-1RA are metabolized in target tissues via the common proteolytic pathway of large proteins, without a specific organ identified as the main route of elimination. They are protected from renal clearance by either their large molecular size or their noncovalent attachment to albumin. Due to their structural similarity to native human GLP-1, their immunogenicity is low . Large-sized GLP-1RA, such as dulaglutide and albiglutide, are bound to large proteins, which makes it difficult for them to cross the blood–brain barrier and reach satiety centers. Therefore, a lower effect on body weight has been seen in clinical trials with these molecules in comparison to small-sized GLP-1 RA such as liraglutide or semaglutide . Classification of GLP-1 RA into short- and long-acting agonists may be more useful from a practical viewpoint. Long-acting GLP-1 RA, such as liraglutide, dulaglutide, once-weekly exenatide or semaglutide, induce prolonged stimulation of the GLP-1R, leading to a greater reduction of fasting plasma glucose and HbA1c. Short-acting GLP-1 RA, such as daily exenatide or lixisenatide, show a lower effect on fasting plasma glucose, basal insulin secretion and HbA1c but induce a more pronounced decrease in postprandial glycemia. The effect of short-acting GLP1-RA on postprandial glycemia seems to be a consequence of delayed gastric emptying. In contrast, the effect of long-acting GLP-1 RA on gastric emptying is lost after a few weeks of treatment due to a tachyphylaxis mechanism .Immunogenicity. Exendin-4 analogs are immunogenic, and, in some patients, the drug is inactivated by antibodies, whereas human GLP-1RA rarely induce antibody formation. Tolerance. Exendin-4 analogs are metabolized and eliminated by the kidneys, so they accumulate in CKD patients (precisely those with the highest cardiovascular risk), which may favor their withdrawal due to gastrointestinal intolerance. Human GLP-1RA, in contrast, are not eliminated by the kidneys.19-36. Exendin-4 analogs are fully resistant to inactivation by DPP-4. Conversely, human GLP-1RA may be partially metabolized to small amounts of the metabolite GLP-19-36, which could have an additional cardioprotective effect, acting in the endothelial mitochondria through a non-GLP-1 receptor pathway.Production of GLP-Human GLP-1RA  have been shown to reduce cardiovascular morbidity and mortality. In contrast, incretin-mimetics  have not demonstrated superiority in cardiovascular outcomes trials. Some experts argue that differences in study design and population, statistical power, adherence, withdrawals or even mere chance may explain these findings . HoweverFrom a pharmacological point of view, GLP-1RA effects are mediated by their target molecule (GLP-1R). In this regard, Takayanagi et al. reported that target molecular occupancy could be a useful parameter for evaluating the clinical efficacy of these drugs . They shThe structural difference in human GLP-1 confers exendin-4 and, by extension, incretin-mimetics, resistance to inactivation by DPP-4. Incretin-mimetics are eliminated mainly by glomerular filtration, tubular reabsorption and subsequent proteolytic degradation, so their clearance is reduced in patients with renal insufficiency. In contrast, GLP-1 analogs are metabolized locally in the target tissues by the common route of large proteins, without a specific organ identified as the main route of elimination. They are protected from renal clearance by their large molecular size or by their non-covalent binding to albumin ,35. A pharmacokinetic study with the administration of a single subcutaneous dose of semaglutide 0.5 mg showed that semaglutide exposure was similar between subjects with mild/moderate renal impairment or end-stage renal disease and subjects with normal renal function. This equivalence was not demonstrated in subjects with severe renal impairment, in which mean exposure was 22% higher . 2, while all exendin-4 analogs are contraindicated below 30 mL/min/1.73 m2, given the risk of accumulation and toxicity [Thus, the European Medicines Agency (EMA) has approved the use of all commercially available human GLP-1 analogs up to eGFR of 15 mL/min/1.73 mtoxicity ,37. GLP-toxicity   , EXSCEL p = 0.04). EXSCEL was the largest study performed in a usual-care setting including 14,752 T2DM patients with or without previous CVD. This study was CV neutral, confirming the noninferiority of once-weekly treatment with 2 mg long-acting extended-release exenatide [p = 0.003) [The first reported trial, ELIXA, conducted in 6068 patients with a history of recent acute coronary syndrome and T2DM, was CV neutral, confirming the noninferiority of lixisenatide for three-point MACE . The secxenatide . The HARxenatide . This tr= 0.003) . PIONEER= 0.003) . This tr= 0.003) . The las= 0.003) . The FREEDOM-CVO trial, designed to test CV safety in a pre-approval setting, evaluated the continuous delivery of exenatide in more than 4000 T2DM patients with CV disease. Although the final results have not yet been published, early on in May 2016, the company press release reported that the study had achieved all its clinical endpoints and was completed on time, confirming noninferiority in terms of CV outcomes .p < 0.0001). HRs were 0.88  for death from cardiovascular causes, 0.84  for fatal or nonfatal stroke and 0.91  for fatal or nonfatal myocardial infarction. GLP-1 receptor agonist treatment reduced all-cause mortality by 12% ), hospital admission for heart failure by 9% ), without increasing the risk of severe hypoglycemia, pancreatitis or pancreatic cancer [A recently published systematic review and meta-analysis of cardiovascular outcome trials with GLP-1RA screened 27 publications and seven of the above-mentioned clinical trials . Overallc cancer .Overall, the clinical trials mentioned in this section demonstrated noninferiority and CV neutrality for exendin-4 GLP-1RA, and cardiovascular protection for human GLP-1RA. This observed differential effect may be ascribed to different causes such as clinical trial design, studied population characteristics, and molecular differences between exendin-4 and human GLP-1RA.All these data prompt the question of whether GLP-1RA has a class effect. Human GLP-1 analogs  have demonstrated CV morbidity and mortality reduction. In contrast, exendin-4 or incretin-mimetic analogs  have not achieved superiority in CV safety studies, a fact that points towards a possible class effect in this group of drugs. Other explanations for these differences include the study designs, populations studied, potency, withdrawals or even mere chance. However, certain molecular differences are likely to have contributed at least partially to these results, which supports the hypothesis of a class effect in GLP-1RA.To date, there are no published GLP-1RA trials with a primary endpoint of kidney events or enrolling only DKD patients. For this reason, insights into the renal impact of GLP-1RA were provided by cardiovascular outcomes trials .2 in 25% of lixisenatide and in 22% of placebo patients. In an exploratory analysis, lixisenatide decreased the percentage of albuminuria change compared to baseline when tested against placebo, although after adjusting for various variables, this was only significant in patients with macroalbuminuria. However, no differences were observed regarding eGFR loss. In the EXSCEL trial [2 in 17% of exenatide and placebo patients. Secondary renal endpoints were not predefined. However, post-hoc analysis demonstrated a significant reduction in the risk of a combined kidney endpoint consisting of a 40% reduction in the rate of eGFR decline, onset of dialysis or transplantation, renal death and onset of macroalbuminuria ) [2, 36% albuminuria >30 mg/g and 10% albuminuria >300 mg/g. Liraglutide decreased by 22% ) the risk of a secondary composite kidney endpoint . This benefit was mainly at the expense of macroalbuminuria reduction, without significant benefit in the other composite endpoint parameters. Interestingly, when results were stratified according to the eGFR at baseline, the decrease in eGFR in patients with a baseline estimated GFR of 30 to 59 mL/min/1.73m2 was 2 mL/min/1.73 m2 in the liraglutide group, compared with 4 mL/min/1.73 m2 in the placebo group ) [2 in 11% of patients. After 1.6 years of follow-up, no significant benefit of albiglutide was observed in the safety endpoint of the eGFR decline rate. To date, no other kidney endpoints have been analyzed. In the REWIND trial [2 in 22% of patients. Dulaglutide achieved a significant 15% risk reduction ) in the renal composite endpoint , mainly driven by decreased new-onset macroalbuminuria. The effect of dulaglutide on renal outcome was further explored in a set of sensitivity analyses, which demonstrated that dulaglutide was associated with reduced incidence of sustained eGFR decline of 40% or more ), and 50% or more ). Consistent with these results, a recently published sub-analysis of another antidiabetic class drug, empagliflozin, a sodium glucose cotransporter-2 inhibitor, demonstrated that lower thresholds of eGFR  were associated with higher event rates but weaker treatment effect, suggesting that in the future renal endpoints should target an eGFR decline above 40% [In the ELIXA  trial ,57, eGFREL trial , eGFR wa 0.027)) . In the  0.027)) ,52, 23% ND trial , eGFR wa2 was present in 28.5% of patients and 12.7% had baseline macroalbuminuria. Semaglutide effected a 36% reduction ) in a secondary combined kidney endpoint . The renal benefit owed mainly to impact on new onset macroalbuminuria . Post-hoc analyses showed a 30% reduction in albuminuria and regression to micro- or normoalbuminuria occurred for all degrees of albuminuria in patients treated with semaglutide [In the SUSTAIN 6 trial , eGFR < aglutide . 2/year, p < 0.001). Slower eGFR decline was also observed when patients with eGFR <60 or >60 mL/min/1.73 m2 were analyzed separately [2 [2; however, this study did not include renal endpoints. Interestingly, in REWIND, LEADER and SUSTAIN 6, no differences were observed in RRT components of the combined kidney endpoint.In a post-hoc analysis, patients on 1 mg weekly subcutaneous dose of semaglutide had significantly slower eGFR loss than those on placebo  or exenatide (59%), GLP-1RA were associated with a systolic BP reduction of 2.22 mmHg (95% CI: –2.97–1.47). In a separate meta-regression analysis, the degree of systolic BP change was not associated with baseline BP, weight loss or improvement in HbA1c . ReductiDirect renal and cardiac effects may also contribute to nephroprotection. The potential mechanisms of direct renal benefit of GLP-1RA are multiple and incompletely understood, most having been demonstrated in experimental animals only. These putative renoprotective actions and effects of GLP-1RA on kidneys are shown in Turning next to the effect on natriuresis, GLP-1 has been demonstrated to induce natriuresis and diuresis, likely involving inhibition of sodium–hydrogen exchanger 3 (NHE3) localized at the brush border of the renal proximal tubular cells . NHE3 acGLP-1RA also decrease circulating concentrations of angiotensin II, an effect that also plays a role in the observed increase in renal sodium wasting , and whi2, p = 0.021) [The question of whether GLP-1RA modulate glomerular hemodynamics is controversial. GLP-1RA may decrease endothelin-1 and angiotensin II-induced vasoconstriction, thus decreasing glomerular hyperfiltration . However= 0.021) . Theoret= 0.021) . This discrepancy may be due to the fact that the renal effect of exenatide in healthy men may differ from that in insulin-resistant subjects and T2DM patients, which could explain the above-mentioned decrease in GFR after GLP-1 peptide infusion in these individuals. However, this was not replicated in patients with T2DM , which wThe net effect GLP-1RA have on glomerular hemodynamics probably depends on the balance of the potential effect on tubule-glomerular feedback of GLP-1RA induced natriuresis (vasoconstriction of the afferent in some patients) vs. vasodilation by nitric oxide, added to the vasodilator effect of the efferent by inhibition of the renin–angiotensin axis and endothelin. The total sum of these divergent forces determines changes in the eGFR, which could explain why in LEADER  and SUSTGLP-1R activation leads to stimulation of cyclic adenosine monophosphate–protein kinase A pathways, producing antioxidative effects; it, therefore, seems likely that GLP-1 protects the kidney from oxidative injury . In the Other putative renoprotective actions of GLP-1RA are the improvement of renal hypoxia related to vascular rarefaction induced by hyperglycemia and anti-atherogenic effects, both directly via an effect on glucose, lipids, weight and BP and possibly indirectly via anti-inflammatory and anti-ischemic activity . 2 or albuminuria 100–5000 mg/g and eGFR 25–50 mL/min/1.73 m2. The primary composite kidney outcome is composed of a persistent ≥50% reduction in eGFR or a persistent eGFR <15 mL/min/1.73 m2 or the initiation of RRT  or renal or cardiovascular death. There are three ongoing studies of GLP-1RA in primary kidney outcomes: Effect of GLP-1RA, liraglutide, on DKD (NCT01847313); Effect of LIXIsenatide on the Renal System (ELIXIRS) (NCT02276196); and The FLOW study  (NCT03819153) . This la2 initiation of chronic renal replacement therapy  is included in the secondary outcomes. In addition, a new GLP-1RA named efpeglenatide is being tested in T2DM patients with established cardiovascular disease or aged over 50 years , 55 years  or older with eGFR ≥25 and <60 mL/min/1.73 m2 and at least one cardiovascular risk factor. In the AMPLITUDE-O trial (Effect of Efpeglenatide on Cardiovascular Outcomes) (NCT03496298), the time to first occurrence of any of the following clinical events: new-onset or progression to macroalbuminuria (>300 mg/g) accompanied by a UACR value increase of ≥30% from baseline, sustained a ≥40% decrease in eGFR from baseline (for ≥30 days), chronic dialysis (for ≥90 days), renal transplant, sustained eGFR <15 mL/min/1.73 m2 (for ≥30 days) is also considered as a secondary outcome.Several randomized clinical trial studies with GLP-1RA are currently ongoing. Among them, the Heart Disease Study of Semaglutide in Patients with T2DM (SOUL) (NCT03914326) focused on evaluating the effect of oral semaglutide in preventing cardiovascular events in T2DM patients with cardiovascular disease or CKD. In this clinical trial, the first occurrence of a composite CKD endpoint, namely renal death/onset of persistent 50% or more reduction in eGFR (CKD-EPI)/onset of persistent eGFR (CKD-EPI) below 15 mL/min/1.73 m2, but this owes mainly to the lack of clinical trials in DKD patients with stage 5 CKD in dialysis programs or kidney transplantation. Thus, the safety of this class of drugs in this specific CKD population is also yet to be resolved. More studies are required in patients with advanced CKD and T2DM.Although several basic research studies and randomized clinical trials focused on GLP-1RA are already underway, the renoprotective mechanisms of GLP-1RA are not completely understood. At the pipeline level, further research is needed on the positive effect in terms of proteinuria, and inhibition of the sodium–hydrogen exchanger 3 (NHE3) localized at the brush border of the renal proximal tubular cells. This direct effect at the proximal renal tubular level may play a role in the differential GFR effect depending on different degrees of DKD. SGLT-2 and GLP-1RA in combination have proven effective in T2DM patients, but whether this drug combination exerts a potentiated or decreased cardiorenal protective effect in patients with moderate-advanced DKD is unknown. The threshold of human GLP-1RA is eGFR under 15 mL/min/1.73 m2, although this is expected to change soon. In contrast, human GLP-1RA can be used up to eGFR of 15 mL/min/1.73 m2. GLP-1RA offer the potential for adequate glycemic control in multiple stages of DKD without an increased risk of hypoglycemia and with additional benefits in weight reduction, cardiovascular outcomes and exploratory kidney outcomes. The ongoing FLOW RCT is assessing the impact of semaglutide on primary kidney outcomes in DKD.Recently, certain glucose-lowering drugs have shown benefits beyond blood glucose control. SGLT2i and GLP-1RA are associated with improved cardiovascular and kidney outcomes. Currently, SGLT2i has regulatory approval only in patients with eGFR >60 mL/min/1.73 m


Oxidative stress is involved in cardiovascular disease such as peripheral artery disease (PAD). Vascular Peroxidase 1 (VPO1), a novel heme-containing peroxidase mainly expressed in the cardiovascular system, aggravates oxidative stress. Evidence in humans is limited. Current work aims to measure VPO1 in patients suffering from PAD, and to evaluate the association of VPO1 with conventional markers of cardiovascular risk factors (CVRF), including the estimated glomerular filtration rate (eGFR) and albuminuria categories.This study is part of a longitudinal observational study. At baseline, 236 PAD-patients were included. VPO1 plasma levels (ng/mL) were measured by commercially available ELISA kits. A two-sided p level of < 0.05 was considered statistically significant.2 eGFR loss per year, (OR per one SD VPO1 1.60 (1.11–2.30); p = 0.009). This association between VPO1 and kidney function withstood the multivariable adjustment for traditional CVRF including baseline eGFR and urine albumin-to-creatinine ratio (UACR), (adjOR per one SD VPO1 1.73 (1.14–2.61); p = 0.046).In the cross-sectional analysis (n = 236), VPO1 associated with ageing (p = 0.035) as well as with eGFR and albuminuria category, the markers of chronic kidney disease (CKD)-progression (p = 0.042). The longitudinal 18-months follow-up analysis (n = 152) demonstrated that baseline VPO1 predicts rapid kidney function decline (RKFD) (n = 49), defined as more than − 3 mL/min/1.73mThis study is first to reveal that VPO1 is independently associated with declining kidney function in patients with PAD. VPO1 shows a tighter association to kidney function than to other CVRF. This finding points to VPO1 as a potential target protein to assess CKD-progression. Peripheral artery disease (PAD) is one of the most common initial presentations of cardiovascular disease diagnosed in elderly patients with type 2 diabetes mellitus (T2DM) . While aVascular peroxidase 1 (VPO1), also known as human peroxidasin homolog, is a newly identified member of the heme-containing peroxidase family . VPO1 isPathophysiologically, VPO1 promotes oxidation of low-density lipoprotein (LDL) and mediates formation of foam cells, a hallmark of atherogenesis . MoreoveThe routine clinical assessment of CKD is established by a decreased kidney function reflected through a decreased estimated glomerular filtration rate (eGFR), or by the presence of kidney damage inferred from clinical markers such as albuminuria . While tWhile several studies have been performed on the role of VPO1 at the cellular level or in animal models , 11, 13,This work is aimed at exploring the association of VPO1 and CVRF that are present in PAD, an occurrence of cardiovascular disease. The character of the study is not mechanistic, and hence it is not aimed at explaining the potential complex biological pathways underlying this association.The current investigation is part of the prospective VMC (vascular medicine center) Vienna observational study of PAD-patients , and wasDiagnosis of PAD utilizing the Fontaine classification was confirmed by the ankle-brachial index  or the toe-brachial index in patients with media-sclerosis , respectively, following the recommendations of the Trans-Atlantic Inter-Society Consensus II for the Management of Peripheral Arterial Disease Working Group .T2DM status was defined by the American Diabetes Association ‘Diagnosis and Classification of Diabetes Mellitus’ .Smoking status was classified as current or former smoker versus never smoker. Respondents who had smoked at least 100 cigarettes in their lifetime were defined as former smokers.Arterial hypertension was defined as blood pressure higher than or equal to 140 mmHg systolic over 90 mmHg diastolic in at least two measurements, or in case of current intake of anti-hypertensive drugs.2 defined CKD, and urine albumin-to-creatinine ratio (UACR) from spot urine beyond 30 mg/g defined abnormally elevated UACR. In addition, patients were classified for CKD combining eGFR and albuminuria categories, ranging from CKD G1 A1 to CKD G4 A3. They were divided into 4 categories of risk of CKD-progression, ranging from low risk to very high risk [Kidney function was assessed by estimating the glomerular filtration rate from serum concentration of creatinine, using the CKD-EPI formula . This stigh risk .2 per year [2 per year, respectively more than − 4.5 mL/min/1.73m2 per 18 months [Considering the longitudinal design of the underlying main study , an analper year . Rapid k8 months , 22.Venous blood samples were drawn after an overnight fast, centrifuged, and stored frozen at − 80 °C, avoiding loss of bioactivity and contamination. After an overnight thawing, concentrations of VPO1 (ng/mL) were measured in patients’ plasma by an enzyme-linked immunosorbent assay (ELISA), using commercially available human kits , following the manufacturer’s instructions . Values Statistical methods were performed applying the statistical software package SPSS 23 . Normal distribution was confirmed using the Kolmogorov–Smirnov test. Quantitative variables with normal distribution (including VPO1) were displayed as mean ± standard deviation (SD), whereas continuous variables with non-parametric distribution were given as median with interquartile range . Categorial data, including nominal, ordinal and dichotomous variables, were represented by number (n) and percentage (%). In order to reduce skewness of distributions in statistical analyses, the variables UACR and C-reactive protein (CRP) were logarithmically transformed.2) test, Fisher’s exact test and binary logistic regression analyses, as appropriate. The cardiovascular-related confounders , LDL, CRP as well as eGFR and UACR) were included as covariates in multivariable models. Adjusted odds ratios (adjOR) were determined by multivariable analyses and presented per one SD increase ). Confounding was identified by a change in OR greater than 10.0%, according to Rothman [Statistical analyses compromised student’s unpaired t-test, Mann–Whitney U, analysis of variance (ANOVA), Kruskal–Wallis (K-W), paired sample t-test, Pearson’s Chi-square  and 108 patients with stage II , , constituting the baseline population.VPO1 mean levels did not differ significantly between persons without and with claudication symptoms . VPO1 was evenly distributed between T2DM and without T2DM .Baseline characteristics are shown across VPO1 tertiles, in Table Decreasing kidney function estimated by eGFR category G1–G4) was associated with an increasing VPO1 level (p = 0.012), as displayed in Fig. –G4 was a2, were performed, intended to examine the impact of other CVRF. Firstly, simple binary logistic regression analysis was calculated taking continuous VPO1 values as independent variable (OR VPO1 1.45 (1.09–1.93); p = 0.010). No confounding was noted between the simple model and the adjusted model for gender, smoking status, HbA1c, SBP, LDL, logCRP and logUACR (adjOR VPO1 1.40 (1.02–1.92); p < 0.001). Additional adjusting for medication including ACE-I or ARB and statins, did not affect aforementioned model (adjOR VPO1 1.40 (1.01–1.93); p < 0.001). According to the adjusted pseudo-R2 measure Nagelkerke, 24.8% of the alteration in eGFR status was explained by this multivariable model; the AUC was computed at 0.756.Since univariate analyses suggested an association between VPO1 and renal parameters, binary logistic regression analyses on dichotomized kidney function, at the eGFR cut-off point of 60 mL/min/1.73mIn order to explore this observation further, longitudinal analyses investigating kidney function decline were assessed. Follow-up data were available 18 months after baseline for 152 female and male adult participants. Patients in this subgroup were similar to the whole study population in regard to PAD Fontaine stage, T2DM status and in any baseline characteristic , with the exception from a decreased LDL level .2 (p = 0.010), resulting in a change of − 1.09 ± 5.11 mL/min/1.73m2 per year. The deterioration in renal function over time was more pronounced in patients within higher VPO1 tertiles at baseline (tertile I (0.59 ± 4.55 mL/min/1.73m2 per year), tertile II (− 1.43 ± 4.81 mL/min/1.73m2 per year) and tertile III (− 2.02 ± 5.57 mL/min/1.73m2 per year), (p = 0.036)). RKFD (> − 4.5 mL/min/1.73m2 per 18 months) was present in 49 patients (32.2%). RKFD was present in 41.2% of patients with T2DM in comparison to 25.0% without T2DM, (p = 0.034). Baseline eGFR mean levels were similar in those with RKFD and those without RKFD . Follow-up eGFR levels were lower .During the follow-up period of 18 months, average rate of change in eGFR ran up to − 1.63 ± 7.67 mL/min/1.73mc, SBP, LDL, logCRP and baseline eGFR (adjOR VPO1 1.73 (1.14–2.61); adjOR logUACR 1.70 (1.15–2.51)). In order to assess the influence of the associated renal parameters as well as their impact on the proposed model, it was re-analyzed excluding the covariates eGFR and logUACR (adjOR VPO1 1.76 (1.19–2.60)). Subsequent adjustment for excluded renal parameters did not alter the initial model. This indicated that the prognostic power of VPO1 is independent from renal parameters.Patients with a RKFD exhibited significantly higher VPO1 as well as elevated UACR at baseline. Both VPO1 (p = 0.009) and logUACR (p = 0.004) revealed to be individually associated with higher risk of RKFD over time (OR VPO1 1.60 (1.11–2.30); OR logUACR 1.67 (1.17–2.38)). In the multivariable binary logistic regression model, elevated VPO1 and logUACR were associated with RKFD (p = 0.046), after correction for the confounders age, gender, smoking status, HbA12 increased to 15.6%, as well as the predictive performance of RKFD improved, as the calculated AUC value increased further by 0.052 . The ROC curve in Fig. Additionally, two models predicting RKFD were compared, one including only traditional CVRF, the other adding the biomarker VPO1. Table We were first to explore VPO1 related to CVRF that are present in patients with PAD, revealing a correlation between VPO1 and worsening kidney function. VPO1 levels associated with eGFR as well as with changes in eGFR, confirming its association with kidney function.c, SBP, LDL, CRP as well as baseline eGFR.Individuals displaying RKFD exhibited higher baseline VPO1 levels compared to those without. The contribution of UACR as well as of VPO1 to risk prediction was greater than that of any other CVRF. Noteworthy, the prognostic value of VPO1 was independent of UACR, the well-known predictor of kidney function decline . Our staOur results are in accordance with previous experimental pre-clinical studies , 13, 15.At this point in time, to the best of our knowledge, we have not observed any study exploring VPO1’s relation to the cardiovascular system, in a PAD cohort. Our study revealed that VPO1 mean levels did not differ between the PAD stages addressing asymptomatic and symptomatic severity grades. Similarly, a study performed in 156 PAD-patients detected no correlation between MPO levels and ABI values . EvidencThis study has its limitations. The protein VPO1 represents a relatively unexplored research area, therefore, generated study hypotheses have to be interpreted carefully. VPO1 is not yet deemed to serve as a biomarker in clinical decision making. In order to determine whether VPO1 is actually a non-invasive marker, mediator and predictor of disease, as well as to determine to what extent assessment of VPO1 might contribute to risk profiling in patients with PAD, further prospective studies are necessary to elucidate associated comorbidities, as PAD as well as CKD have multifactorial etiologies. Due to current study design we cannot infer that the association between VPO1 and kidney function is causal. Another potential limitation is that this single-center study was performed in a Caucasian patient cohort. Thus, generalization of these findings should be validated in other patient cohorts.Individuals with RKFD are reported to have increased cardiovascular as well as all-cause mortality risks, regardless of baseline demographic and kidney function parameters . Our CoxThe protein VPO1 is promising to reflect kidney function in PAD Fontaine stage I and stage II, independent of UACR and other cardiovascular-related risk parameters.