Exercising at different times of the day is a widely employed strategy for treating essential hypertension, aimed at enhancing the circadian rhythm of blood pressure. This study aimed to investigate the effects of Liuzijue exercise in the morning and afternoon on the circadian rhythm of blood pressure in patients with essential hypertension.This clinical randomized trial recruited 36 patients. They were randomly divided into 3 groups: morning exercise, afternoon exercise, and waiting treatment group. Randomization was performed at a ratio of 1:1:1, ensuring an equal distribution of participants among the 3 groups. Based on maintaining routine work and rest and continuing the original drug treatment, the exercise performed Liuzijue exercise for 12 weeks. The exercise time was 9:00 to 10:00 in the morning exercise group and 14:00 to 15:00 in the afternoon exercise group. The waiting treatment group did not perform any form of fitness exercise. The subjects in the 3 groups were monitored by 24-hour ambulatory blood pressure on the day before and after the first day.P < .01). In contrast, the waiting group experienced substantial increases in 24-hour mean systolic blood pressure (24hSBP), 24-hour mean diastolic blood pressure (24hDBP), mean systolic blood pressure during the daytime (dSBP), and mean diastolic blood pressure during the daytime (dDBP) (P < .01). Further analysis showed that the morning exercise group had significantly lower 24hSBP, 24hDBP, dSBP, dDBP, and mean systolic blood pressure during the night than the waiting group (P < .05). Additionally, the morning exercise group had lower 24hSBP and dSBP levels than the afternoon exercise group (P < .05). In contrast, the afternoon exercise group had lower 24hDBP and dDBP than the waiting treatment group (P < .05).After the 12-week Liuzijue exercise intervention, mean systolic blood pressure during the night significantly decreased in the morning exercise group (The 12-week Liuzijue exercise in the morning regimen demonstrated superior efficacy in reducing 24-hour ambulatory blood pressure levels among patients with essential hypertension. Moreover, it facilitates the transition of non-dipper blood pressure patterns to dippers, thereby rectifying aberrant circadian rhythms. Compared to the normal blood pressure rhythm of higher levels during the day and lower levels at night, individuals with essential hypertension exhibit an inability of their blood pressure to drop adequately during the night. This phenomenon can lead to an abnormal blood pressure state, characterized by elevated levels at night and lower levels during the day. Such abnormal patterns worsen damage to target organs and increase the risk of developing atherosclerosis, stroke, and other related diseases.,3 Therefore, selecting the optimal timing for administering antihypertensive medications or implementing non-pharmacological therapies based on the fluctuation rhythm of blood pressure represents the principal intervention for effectively managing abnormal blood pressure patterns in individuals diagnosed with essential hypertension.Essential hypertension is a chronic cardiovascular disease characterized by increased systemic arterial systolic and diastolic blood pressure. The abnormal increase in blood pressure usually leads to pathological blood pressure variation, and blood pressure which increases sharply or decreases excessively. This exercise has been shown to effectively lower and regulate blood pressure variability in individuals diagnosed with essential hypertension. Its unique combination of exercises targets aerobic capacity and flexibility, yielding notable benefits for hypertension patients regarding blood pressure management and stability. However, few studies have investigated the combined effects of chronotherapy and exercise therapy, particularly in determining the optimal timing for the effectiveness of Liuzijue exercise in reducing blood pressure and normalizing the circadian rhythm of blood pressure. Therefore, this study aimed to investigate the effects of Liuzijue exercise in the morning and afternoon on 24-hour ambulatory blood pressure and circadian rhythm in patients with essential hypertension.Liuzijue exercise is a low-intensity aerobic exercise that combines resistance exercise with flexibility training.This was a randomized controlled study to determine the effect of Liuzijue exercise in different periods on the circadian rhythm of blood pressure in patients with essential hypertension. The Medical Ethics Committee of the Affiliated Hospital of Chengdu University of TCM approved the study. Prior to commencing the intervention, a comprehensive explanation outlining the precise objectives, methodology, intervention schedule, anticipated advantages, and potential risks of the study was provided to all participants. By rigorously adhering to the principle of voluntary participation, individuals were duly informed, and their consent was obtained through the signing of an informed consent form prior to their inclusion in the study. To ensure the safety of the participants, stringent termination criteria were applied and adhered to throughout the study. Throughout the intervention period, the participants retained their autonomy to withdraw from the study based on their individual circumstances. Participants’ personal information and related records were kept strictly confidential.From March 2019 to September 2020, patients diagnosed with essential hypertension who met the predetermined inclusion criteria were prospectively selected from the Ninth People’s Hospital of Qingyang District, Chengdu, and the Daying Hospital of TCM in Suining City, Sichuan.; they did not have systematic exercise habits, which referred to engaging in a singular exercise session lasting <30 minutes per day or participating in exercise fewer than 2 times per week; they were undergoing treatment with calcium channel blockers (such as nifedipine) had not altered their medication regimen in the immediate period prior to the study; they did not have any underlying conditions that impact motor function or exhibit severe motor dysfunction; they abstained from the use of any blood-activating and stasis-resolving traditional Chinese medicines, antibiotics, corticosteroids, or microbial preparations in the month preceding the study; they had no previous history of gastrointestinal disorders; they had not taken part in clinical trials involving Taijiquan, Baduanjin, or other traditional Chinese medicine exercise therapies within the preceding 6 months were included in the study.Participants were included if they satisfied the following criteria: they were aged 50 to 80 years old; they met the diagnostic criteria of hypertension in the 2018 Chinese guidelines for the management of hypertension, hypertension was defined as systolic blood pressure ≥ 140 mm Hg (1 mm Hg = 0.133 kPa) and diastolic blood pressure ≥ 90 mm HgParticipants were excluded from the study if they met any of the following criteria: they had secondary hypertension; they had grade 3 hypertension, which is characterized by a systolic blood pressure equal to or >180 mm Hg and a diastolic blood pressure equal to or >110 mm Hg; they had hypertension that placed them at a high or very high cardiovascular risk level; they had hepatorenal and cardiac dysfunction, diabetes, chronic gastrointestinal diseases, or other serious complications; they were addicted to smoking and drinking for a long time; they had a history of severe trauma or surgery within the past 6 months and were deemed unsuitable for participation in sports activities; and they had a mental illness or poor compliance, referring to the inability or unwillingness to follow instructions or protocols.Ultimately, 36 participants met the specified criteria. Professional statisticians employed the random number table method to allocate all subjects into the morning exercise group, afternoon exercise group, and waiting treatment group in a 1:1:1 ratio.Due to the open and observational nature of the study, the blinding method was not employed. Nevertheless, efforts were made to utilize objective evaluation indicators to minimize human interference with the test results. Throughout the experiment, there was no communication among the 3 groups of subjects during the intervention, and the staff responsible for recruiting subjects had no knowledge of the experimental group.Participants avoid participating in fitness exercises while following their current treatment program. Those currently taking medication should continue taking levamlodipine 2.5 mg once daily in the morning. Those not presently taking medication would not receive any additional medication. Participants were instructed to maintain a balanced diet, regular daily routine, stable mental state, and to avoid emotional triggers. Additionally, it was advised throughout the experiment to minimize antibiotics and traditional Chinese medicines that could affect the test indices, such as those promoting blood circulation or removing blood stasis. Following the 12-week intervention period, subjects in the control group were free to decide whether to incorporate Liuzijue exercise into their routine based on their personal preferences.The participants in the treatment group adhered to their routine drug treatment program while maintaining the same diet and daily regimen as those in the waiting treatment group. Additionally, they performed Liuzijue exercises for 12 weeks. Before the formal commencement of the experiment, qualified healthcare professionals provided group instruction and training sessions on the “Liuzijue Exercise of Fitness Qigong.” The State Administration of Sports of China developed and endorsed the exercise in 2003. The teaching sessions covered essential components such as breath guidance, pronunciation for exhalation, key body movement points, and precautions. The aim was to ensure consistent execution of movements, posture, frequency, and mental focus among subjects. The regimen was officially implemented only after healthcare professionals confirmed that the issues had mastered the principles and steps of the Liuzijue exercise program. Exercise sessions were scheduled for 1 hour, specifically on Mondays, Wednesdays, and Fridays, from 9:00 to 10:00 each week. The exercise routine consisted of 2 minutes of preparatory activities, including chest expansion exercises, stretching exercises, and other actions to stretch out the joints and muscles of the whole body. This was followed by 56 minutes of exercise, with each set of movements lasting approximately 13 minutes. The entire collection of moves was performed 4 times, with a 2-minute break between each 2 times. After the exercise, there were approximately 2 minutes for finishing activities, where some simple relaxation movements and stretching, such as patting the leg muscles and moving all joints, were performed. Tailored exercise intensity was developed based on the individual circumstances of each participant. In other words, during the exercise process, the participant’s heart rate needed to reach the target heart rate for 5 to 10 minutes. The formula for calculating the target heart rate was: [(220-age)-resting heart rate]*(60–80%) + resting heart rate.The sessions lasted for 1 hour between 14:00 and 15:00. The remaining interventions were consistent with the aforementioned details.The outcome measures were 24-hour ambulatory blood pressure and nocturnal blood pressure drop patterns. These measurements were taken on the day before and after intervention.An ambulatory ECG blood pressure recorder (model BOX) manufactured by Zhongjian Instrument Co., Ltd in Wuxi City, Jiangsu Province, was used to monitor the following parameters: 24-hour mean systolic blood pressure (24hSBP), 24-hour mean diastolic blood pressure (24hDBP), mean systolic blood pressure during the daytime (dSBP), mean diastolic blood pressure during the daytime (dDBP), mean systolic blood pressure during the night (nSBP), and mean diastolic blood pressure during the night. These measurements were taken the day before and after the 12-week intervention period. Monitoring commenced at 8:30 and concluded at 8:30 the following day. For daytime monitoring (6:00–22:00), the ambulatory ECG and blood pressure recorder were configured to record data every 30 minutes. The cuff was automatically inflated to measure the blood pressure during this period. During nighttime monitoring (22:00–6:00 the next day), blood pressure was measured every 60 minutes using the same automatic cuff inflation method. Patients were instructed to keep their hands still and rest their arms naturally on their sides during blood pressure measurements using an ambulatory blood pressure instrument. This protocol ensured a minimum of one blood pressure reading per hour throughout the monitoring period, with at least 20 readings during the day and 7 reading at night. Additionally, the study aimed to obtain adequate blood pressure readings constituting over 70% of the total monitoring time.This study calculated the nocturnal blood pressure reduction rate according to the subjects’ changes in dSBP and nSBP. The specific calculation method was as follows: nocturnal blood pressure reduction rate = (dSBP − nSBP)/dSBP. Patients with 10% ≤ nocturnal blood pressure reduction rate <20% were classified as having a dipper nocturnal blood pressure decline pattern; patients with nocturnal blood pressure decrease rate < 10% or nocturnal blood pressure decrease rate ≥ 20% were classified as having a non-dipper blood pressure pattern.x̄±s). One-way analysis of variance was used for comparison between groups. The constituent ratios were compared using the χ2 test or Fisher exact probability method, depending on the specific circumstances. For within-group comparisons before and after the experiment, a paired-sample t-test was used to assess the statistical significance of observed changes. P < .05 was considered significant.Statistical analysis was performed using SPSS version 26.0. The experimental data are presented as mean ± standard deviation . In the afternoon exercise group, there were 6 male and 6 female patients, averaging 65.67 ± 5.97 years old. Patients in the waiting group comprised 5 male and 7 female patients, averaging 61.25 ± 4.39 years old. Other baseline characteristics include height, weight, and body mass index. Statistical analysis showed no significant differences in these characteristics among the 3 groups. Participants’ characteristics are presented in Table P > .05). After the 12-week Liuzijue exercise intervention, the nSBP in the morning exercise group decreased significantly. Conversely, the waiting group exhibited significant increases in 24hSBP, 24hDBP, dSBP, and dDBP (P < .01).The results of 24-hour blood pressure changes in the 3 groups before and after the experiment are shown in Figure P < .01). Additionally, the 24hSBP, dSBP, and nSBP in the morning exercise group were lower than those in the afternoon exercise group(P < .05). Moreover, the afternoon exercise group displayed significantly lower 24hDBP and dDBP levels than the waiting group(P < .01). No statistically significant changes were observed in any of the other indices (P > .05).The difference of 24-hour ambulatory blood pressure among the 3 groups after the experiment is shown in Figure P > .05). After completing a 12-week intervention involving Liuzijue exercise, notable improvements were observed in the participants’ abnormal nocturnal blood pressure drop pattern. In the morning exercise group, 2 subjects transitioned from a non-dipper nocturnal blood pressure drop pattern to a typical dipper nocturnal blood pressure decrease pattern, increasing the proportion of patients with dipper blood pressure from 16.7% to 33.3%. Similarly, 3 participants in the afternoon exercise group switched to the nocturnal blood pressure decrease pattern, leading to a proportional increase from 16.7% to 41.7%. There were no changes in the waiting group’ number or the proportion of patients with dipper blood pressure. Moreover, no significant differences were observed in the proportion of individuals with dipper blood pressure between the 3 groups before and after the experiment (P > .05).The number and proportion of patients with dipper blood pressure patterns before and after the trial in the 3 groups are shown in Table ,9 Circadian rhythm is characterized explicitly by a long-handle dipper curve, referred to as the “two-peak and one-valley” patterns. It begins with a gradual increase during the daytime and peaks at 9:00 to 11:00, after which it gradually declines. This pattern was followed by another rise around 15:00 to 18:00, followed by a gradual descent that persisted until nighttime. The abnormal increase in blood pressure in patients with essential hypertension is usually accompanied by weakening or disappearance of the blood pressure circadian rhythm. In contrast, high nocturnal blood pressure can transform patients from regular dipper nocturnal blood pressure patterns to non-dipper nocturnal blood pressure drop patterns. The latter increases the risk of stroke, renal dysfunction, and left ventricular hypertrophy and aggravates the damage to the cardiovascular system, kidney, and other organs. Therefore, some researchers have proposed the organic integration of hypertension treatment plans with the circadian rhythm of blood pressure fluctuation4. By adjusting the treatment timing, correcting the abnormal blood pressure circadian rhythm, and considering the antihypertensive effects, the objective is to attenuate target organ damage and effectively prevent and treat associated diseases.Human blood pressure exhibits a distinct circadian rhythm. It is influenced by various humoral factors, including the vascular endothelial system, renin–angiotensin–aldosterone system, catecholamines, other vasoactive substances, and autonomic and central nervous system.,12Liuzijue exercise is a traditional Chinese fitness practice emphasizing controlled exhalation and inhalation techniques, accompanied by pronouncing 6 specific characters: “Xu, He, Hu, Si, Chui, Xi.” These exercises were supplemented with simple arm-and-foot exercises to achieve the best results. Through exhalation and inhalation, the airflow vibrates and, exercises the 6 viscera of the liver, heart, spleen, lung, kidney, and gallbladder. The vibrations generated by the airflow were transmitted inside and outside the body simultaneously. The pronunciation of the corresponding mouth shape will resonates with the corresponding organs when transmitted internally. The guiding actions of the hands and feet jointly stimulate the circulation of the corresponding meridians of the Zang organs and promote the movement of qi and blood in the meridians to achieve the effects of fueling and dispelling evil and treating diseases. Compared to aerobic endurance exercises, such as jogging and swimming, Liuzijue presents a more conservative and gentle exercise approach with a narrower intensity range. Moreover, its versatility allows for its practical use in various environments, making it particularly suitable for individuals with high blood pressure. Notably, several studies have demonstrated that engaging in Liuzijue exercise can enhance vascular function, regulate intestinal flora composition, reduce blood pressure levels and stabilize blood pressure variability.The results of this study showed that the 24-hour ambulatory blood pressure of the 2 groups of subjects who received 12 weeks of exercise intervention improved to varying degrees after the experiment. Simultaneously, a rising trend was observed in the proportion of patients displaying a dipper blood pressure pattern within both the morning and afternoon exercise groups when compared to preexperiment measurements. Among them, the patients who engaged in the morning Liuzijue exercise exhibited a notable improvement in 24-hour ambulatory blood pressure. The research findings demonstrate that practicing Liuzijue exercises in the morning confers significant benefits to patients with essential hypertension. These benefits include the effective reduction of 24-hour ambulatory blood pressure, regulation of blood pressure variability, and facilitation of the transition from a non-dipper blood pressure pattern to a regular dipper blood pressure pattern.,14 Relevant studies have shown that Liuzijue exercise can upregulate plasma NO levels in patients with hypertension by enhancing the NO release pathway. Furthermore, it effectively reduces the levels of ET-1 in patients, subsequently diminishing its vasoconstrictive effect while improving blood pressure. Therefore, Liuzijue exercise can promote restoration of the normal circadian rhythm of blood pressure. Shao found that administering antihypertensive treatment prior to the peak of blood pressure yielded the most pronounced effect in increasing plasma NO levels. In this study, the exercise timing for patients in the morning exercise group was aligned with the daily morning peak (9:00–11:00) of blood pressure. Consequently, engaging in Liuzijue exercise in the morning has a more favorable impact on enhancing the circadian rhythm of blood pressure.The vasoconstrictive factors endothelin (ET) and vasodilatory factor nitric oxide (NO) are crucial vasoactive substances that maintain basal tension in blood vessels. ET induces vascular smooth muscle contraction, thereby increasing blood pressure and augmenting peripheral vascular resistance. Conversely, NO can relax vascular smooth muscle cells and inhibit their proliferation, which actively regulates blood pressure and prevents excessive elevations. Moreover, studies have revealed the potential involvement of both NO and ET in regulating the circadian rhythm of blood pressure. Erdem observed that the heart rate variability index was significantly lower in non-dipper-type hypertensive patients, suggesting that cardiac autonomic dysfunction is closely related to blood pressure rhythm changes in patients with early hypertension. Salles also found that the heart rate variability index decreased in patients with resistant hypertension, indicating that the weakened nighttime blood pressure drop was mainly related to significantly enhanced sympathetic nerve activity. A previous study demonstrated that regular aerobic exercise improved cardiovascular autonomic imbalance in individuals with hypertension. In our study, performing Liuzijue exercises in the morning significantly increased the daytime blood pressure. This improvement can be attributed to exercise’s ability to regulate autonomic nerve function and mitigate sympathetic nerve activity throughout the day.Alterations in the circadian rhythm of blood pressure are correlated with disturbances in autonomic function. Such disruptions primarily manifest as an imbalance between the sympathetic and the parasympathetic nervous systems. Under normal physiological conditions, the human body engages in increased mental and physical activity during the daytime, which incites sympathetic nerve arousal and subsequently drive elevated blood pressure. Conversely, activity levels subside during nocturnal sleep, triggering heightened parasympathetic nerve activity and diminishing sympathetic nerve activity. Consequently, blood pressure decreases during nighttime hours. The fibrinogen, Hct, ηb, ηp, ηbI, and erythrocyte agglutination index were significantly higher in the non-dipper group than in the dipper group. This phenomenon arises from the correlation between heightened blood viscosity and reduced vascular shear stress, resulting in diminished release of NO. These cascading effects compromise the vascular endothelial function, ultimately contributing to the development of abnormal circadian rhythms. Moreover, there is circadian rhythm in hemorheology. Wu found that the hemorheological parameters of rats demonstrated significantly higher blood viscosity during the day than night. A recent study demonstrated the effectiveness of Liuzijue exercise in reducing blood viscosity among individuals diagnosed with Diabetic Nephropathy. Hence, our study proposes a potential mechanism wherein engaging in Liuzijue exercise during the morning leads to an enhanced reduction in blood pressure viscosity throughout the day. Subsequently, it can lead to decreased blood pressure and improved abnormal blood pressure circadian rhythm in patients.Furthermore, the aberrant circadian rhythm of blood pressure is intricately linked to hemorrheology. Qin conducted a comparative analysis of the hemorheological parameters among 148 patients diagnosed with essential hypertension. These impulses subsequently travel through the retinal hypothalamic pathway to reach the suprachiasmatic nucleus (SCN). The SCN, as the central component of the biological clock, houses oscillators that govern the circadian rhythms of various physiological activities in the human body. Hence, ambient light can modulate the circadian rhythms of these physiological processes by influencing the SCN. Gubin investigation demonstrated a notable increase in nSBP due to light exposure, resulting in an abnormal nocturnal blood pressure decline. Simultaneously, light hinders the secretion of melatonin (MT), subsequently leading to decreased blood pressure. Given that this study was conducted in an outdoor setting , variations in ambient light levels may account for the divergent effects of Liuzijue exercise on blood pressure circadian rhythms in the morning and afternoon. Notably, afternoon light intensity is higher compared to the morning, which, under its influence, results in Liuzijue practitioners in the afternoon not exhibiting a significant improvement in 24-hour ambulatory blood pressure which, under its influence, results in Liuzijue practitioners in the afternoon not exhibiting a significant improvement in 24-hour ambulatory blood pressure.In the regulation of circadian rhythms in mammals, ambient light plays a highly significant role. Following the reception of external light cues, retinal ganglion cells convert ambient light intensity signals into nerve impulses.In 1983, the World Health Organization recommended nondrug therapy as a preliminary and adjuvant treatment for mild-to-moderate hypertension. Previous studies have shown that Liuzijue exercise can effectively lower blood pressure and improve cardiovascular function. However, few studies have focused on the best performance of Liuzijue exercise. This study’s innovation combines chronotherapy with sports medicine, and find that the morning is more suitable for exercise with essential hypertension. In the future, we can further develop the influence of the duration and intensity of Liuzijue exercise on treating diseases and develop an exercise prescription that is more suitable for patients with essential hypertension.This study has several limitations. First, the sample size was small, with only 36 participants included, which may limit the generalizability of the findings. Second, the intervention duration was relatively short, consisting of only 12 weeks of Liuzijue exercise, which may need to be increased to capture the long-term effects or changes in the subjects’ blood pressure patterns. Additionally, the study only focused on the effects of Liuzijue exercise in the morning and afternoon on the circadian rhythm of blood pressure in patients with essential hypertension without exploring other potential impacts or variables. This physiological phenomenon may have exerted some influence on the outcomes of our study. Nevertheless, prior research has indicated that gender does not impact other circadian rhythm changes in blood pressure, specifically the transition between “dipper” and “non-dipper” patterns. Because the number of cases included in this study is small, and the ambulatory blood pressure of the subjects in the AEG group and the WTG group with fewer males is still higher than that in the MEG group after the experiment, we believe that the gender differences among the 3 groups do not bias the results of the study.It is noteworthy that in this study, 8 men were assigned to the MEG, whereas only 5 were assigned to the WTG. This variation can be attributed to the constraints imposed by experimental conditions and methodologies. Ben-Dov conducted ambulatory blood pressure monitoring in 3957 patients between 1991 and 2005, and his findings revealed that ambulatory blood pressure typically exhibited lower values in women compared to men.In future research, it would be beneficial to investigate the effects of exercise at different times of the day on vascular endothelial function, hemodynamics, or other relevant factors to provide a more comprehensive understanding.In conclusion, this study revealed that morning Liuzijue exercise exhibited superior efficacy in enhancing abnormal blood pressure circadian rhythm among patients with essential hypertension, surpassing the effects of afternoon exercise. Furthermore, it facilitates the conversion of non-dippers to dippers. The specific mechanism of action warrants further exploration in future studies.Conceptualization: Kaidi Nie, Lina Xia.Data curation: Yixiao Chen.Formal analysis: Yixiao Chen.Investigation: Yuyan Guo, Caiping Zheng, Dijun Fu, Yugang Cai.Methodology: Yixiao Chen, Nannan Liu, Kaidi Nie, Lina Xia.Supervision: Lina Xia.Visualization: Yixiao Chen, Nannan Liu.Writing – original draft: Yixiao Chen.Writing – review & editing: Nannan Liu, Lina Xia.


In renal transplantation, warm ischemia time is the interval from the removal of a procured kidney from ice storage to initiating graft reperfusion. Successful kidney transplantation depends on warm ischemia time. The study aims to find the mean warm ischemia time among kidney transplant patients in a tertiary care centre.This descriptive cross-sectional study was conducted among kidney transplant patients in a tertiary care centre. Data from 15 December 2012 to 15 October 2022 were collected between1 December 2022 to 4 January 2023 from the hospital records. Ethical approval was taken from the Nepal Health Research Council (Reference number: 1341). All first-time living-related kidney transplant recipients were included in the study. All the patients undergoing kidney transplants from brain-dead donors were excluded from the study. Convenience sampling method was used. Point estimate and 95% Confidence Interval were calculated.Among 230 patients, the mean warm ischemia time was 35.45±7.35 min. The mean first warm ischemia time was 4.28±2.05 min and the mean second warm ischemia time was 31.27±7.04 min. The mean age of the recipients was 35.14±10.49 years (range 14-64), of which 173 (75.20%) were male and 57 (24.80%) were female.The mean warm ischemia time among kidney transplant patients in a tertiary care centre was similar to the studies done in similar settings. There are two distinct phases of WIT. First WIT is the time a kidney remains at a body temperature after cutting off the blood perfusion by clamping a renal artery before it is cooled in ice storage and the second WIT is the period from the removal of an organ from cold storage to reperfusion. Successful kidney transplantation (KT) depends on factors like short WIT.3 There is a substantial rise in WIT in the present era of laparoscopic nephrectomy compared to open nephrectomy.4 In Nepal, studies on WIT have not been carried out yet as Nepal has merely stepped into the second decade of a KT. There is a substantial knowledge gap related to KT in Nepal.Recent studies have identified rising WIT as a risk factor for poor early graft function.The aim of this study was to find out the mean warm ischemia time among kidney transplant patients in a tertiary care centre.This descriptive cross-sectional study was conducted in the Department of Transplant Surgery in Shahid Dharmabhakta National Transplant Center, Dudhpati, Bhaktapur, Nepal from where data from was collected from the hospital record section. Data from 15 December 2012 to 15 October 2022 were collected between 1 December 2022 to 4 January 2023 from the hospital records. The ethical approval was taken from the Nepal Health Research Council (Reference number: 1341). All first-time living-related kidney transplant recipients were included in the study. All the patients undergoing kidney transplants from brain-dead donors were excluded from the study. Convenience sampling method was used. The sample size was calculated using the following formula:Where,n = minimum required sample sizeZ = 1.96 at 95% Confidence Interval (CI)σ = standard deviation is taken as 37.9 from published literaturee = margin of error, 5%6The minimum required sample size was 221. However, the final sample size taken was 230. The patient's demographic and clinical characteristics were recorded as per the proforma. Total WIT was grouped as short (<30 mins), intermediate (30-45 mins), and prolonged (>45 mins).Data were entered in Microsoft Excel 2016 and analysed using IBM Statistics SPSS 18.0. Point estimate and 95% CI were calculated.Among 230 patients, the mean WIT was 35.45±7.35 mins. The mean first WIT was 4.28±2.05 mins and the mean second WIT was 31.27±7.04 mins. The mean age of the recipients was 35.14±10.49 years (range 14-64), of which 173 (75.20%) were male and 57 (24.80%) were female. The mean hospital stay was 14.57±8.25 days. Only 15 (6.50%) of the cases had prolonged WIT .Among 230 patients, 161(70%) patients hadintermediate warm ischemia time .The mean age of patients was 35.14±10.49 years. Among 230 patients, 173 (75.20%) were male .7 In our study, 161 (70%) of cases had intermediate WIT, followed by 54 (23.5%) with short WIT and 15 (6.5%) of cases had prolonged WIT. Similarly, a study in China showed first WIT of 3.7±3.3 mins in living-donor renal transplant patients.8 A multicenter study in Canada showed median total WIT of 35 mins (Q1-Q3: 27-45 mins).9 The WITs in these studies are similar to our study findings.In our study, we defined total WIT as the summation of first WIT and second WIT. Among 230 patients, the mean WIT was 35.45±7.35 mins. A study in Indonesia showed a total WIT of 36.56 mins.10 However, we cannot associate these factors as the cause of the prolonged WIT at our centre due to the descriptive nature of our study. Many factors determine the early outcome of a living donor kidney transplant (LDKT). The impact of cold ischemia time (CIT) has been studied widely.11 However, very less is known about the impact of WIT and its impact on early outcomes such as delayed graft function (DGF). The pathophysiology behind this is that as the kidney is removed from the cold storage, the temperature of the allograft can rise to 15°C within 20 mins. This temperature is a metabolic threshold at which cellular metabolism increases, likely damaging the transplanted allograft by ischemia-reperfusion injury.12 This can be manifested clinically as DGF which requires a longer hospital stay for medical management. Interestingly, there is conflicting evidence of the relationship between prolonged WIT and Length of hospital stay (LOS). In a study, it was found that WIT greater than 29 min increased the risk of DGF by 3.5 times and every added 5 min resulted in 1 extra day in the hospital.3 On the contrary, another study showed no correlation between WIT and LOS.12 For future studies, it will be beneficial to measure the association between WIT on LOS as the optimal LOS can help in minimizing health resources and costs without compromising quality care.Many studies showed that recipients' body mass index, multiple renal arteries, and right donor kidney are the three main risk factors of prolonged (>40 mins) WIT.14 However, in our case, WIT became an area of research due to the conduction of a high volume of renal transplantation surgery. In Nepal, the KT procedure is relatively at a younger stage, and study related to KT is fewer. Therefore, there is a big knowledge gap related to KT; up to now, there is no study of WIT during KT in Nepal. In this study, we tried to show the WIT in renal transplantation procedures.Globally, WIT has become an interesting research topic due to the sudden increment in procedures like partial nephrectomy for cancer treatment.There are a few limitations in this study. This is a descriptive study, therefore, the analytical parameters could not be evaluated. Also, the study is based on a single centre and the findings of this study cannot be generalized to the general populations across the nation unless similar findings are seen in other transplant centres.The warm ischemia time of renal transplant procedure at our centre was found to be similar to studies done in other international renal transplant centres. The majority of the patients have short to intermediate warm ischemia time.


Sodium-glucose cotransporter-2 inhibitors (SGLT2is) have been shown to improve cardiovascular and renal outcomes in patients with established cardiovascular disease, chronic kidney disease (CKD), and heart failure (HF) with reduced or preserved ejection fraction. Clinical benefit has been substantiated in patients with and without type 2 diabetes (T2D). Consequently, SGLT2is have an increasingly important role in HF and CKD management that extends beyond T2D treatment. Their pleiotropic pharmacological effects underlying their cardiovascular and renal benefits are not completely understood but include significant effects beyond blood glucose reduction. SGLT2is inhibit the reabsorption of glucose and sodium in the proximal tubule which, in addition to lowering blood glucose, activates tubuloglomerular feedback, leading to reduced glomerular hydrostatic pressure and the mitigation of glomerular filtration rate loss. SGLT2is have diuretic and natriuretic effects, leading to decreased blood pressure, preload, and left ventricular (LV) filling pressure, and improvements in other surrogates of afterload. In HF, SGLT2is mitigate the risks of hyperkalemia and ventricular arrhythmia and improve LV dysfunction. SGLT2is also reduce sympathetic tone and uric acid levels, increase hemoglobin levels, and are postulated to have anti-inflammatory properties. This narrative review discusses the multifactorial and interrelated pharmacological mechanisms underlying the cardiovascular and renal benefits of SGLT2is. Cardiovascular disease (CVD), chronic kidney disease (CKD), and type 2 diabetes (T2D) are chronic progressive diseases with considerable overlap. Almost half (49%) of US adults aged ≥20 years have CVD ; the prevalence of CKD and T2D among US adults is approximately 15% and 10%, respectively [Pathologies of the cardiovascular and renal systems are linked, with disorders of one system frequently involving the other in a cardiorenal continuum . PatientIn the last decade, sodium-glucose cotransporter-2 inhibitors (SGLT2is) have been shown to provide clinical benefits across the cardiorenal spectrum. SGLT2is were originally developed and approved as glucose-lowering drugs for patients with T2D ,11,12,13US and European treatment guidelines recommend SGLT2is to reduce the risk of HF, MACE, cardiovascular death, and progression of kidney disease in patients with T2D with established CVD or multiple risk factors for CVD ,34,35,36SGLT2is have pleiotropic pharmacological effects that include those related to their glucose-lowering effects and those that are independent of glucose lowering effects. Some pharmacological mechanisms, such as the effects on sodium-glucose cotransporter-2 (SGLT2), are well understood and linked to evidence in clinical outcome studies. Other mechanisms are putative, based on small clinical studies or preclinical data, and their relationship to clinical outcomes is less certain. In particular, the mechanistic links between SGLT2is and the clinical benefits observed in large CVOTs have not been fully elucidated. The aim of this narrative review is to provide an overview of the glucose-independent mechanisms that may contribute to the cardiovascular and renal protective effects of SGLT2is irrespective of a patient’s glycemic status.A targeted literature search of PubMed was conducted to identify relevant English-language publications using the following search terms:  AND  AND . English-language papers published between July 2015 and December 2022 reporting clinical studies and meta-analyses of SGLT2is were identified. Additional relevant studies were identified from the bibliographies of these publications. SLC5A2), which is expressed almost exclusively in the kidney, whereas sodium-glucose cotransporter-1 (SLC5A1) is expressed mainly in the small intestine and to a small extent in the kidney [Under normal physiological conditions, the kidneys contribute to glucose homeostasis by reabsorbing almost all of the glucose in the glomerular filtrate with a negligible amount excreted in urine . This ise kidney . SGLT2 ie kidney . After be kidney ,41.2 and is negligible in patients with a GFR of 30 mL/min/1.73 m2 or lower [Inhibition of SGLT2 blocks reabsorption and increases renal excretion of glucose . This reor lower ,48,49. Ior lower ,50. By por lower ,52.The cardiorenal effects of SGLT2is are not the result of glucose-lowering activity alone, because they are observed sooner than would be expected for a glucose-mediated mechanism of action, are sustained with continued use, and are independent of T2D status. Moreover, cardiorenal benefits are not observed with most classes of anti-hyperglycemic drugs . This reGlomerular filtration is regulated, in part, by tubuloglomerular feedback. Increasing sodium chloride concentrations in the distal tubule cause a release of adenosine from cells in the macula densa, which results in constriction of afferent (precapillary) glomerular arterioles and a reduction in the GFR. The expression and activity of SGLT2 are increased in patients with T2D , resultiSGLT2i therapy mitigates these effects by blocking the reabsorption of glucose and sodium in the proximal tubule. Solute delivery to the macula densa is restored and tubuloglomerular feedback is activated, which results in constriction of afferent arterioles, reduced intraglomerular pressure, and decreased hyperfiltration  37,57,5,59. Redu2 during the first 2–6 weeks of SGLT2i treatment [2 or progression to end-stage kidney disease [Clinically, the restoration of tubuloglomerular feedback manifests as an acute decrease in the estimated glomerular filtration rate (eGFR) of ~5 mL/min/1.73 mreatment ,65,66,67reatment ,62,63,64reatment ,68, and reatment ,69. In D disease . Rather,Data from EMPA-REG OUTCOME ,63, DECLSGLT2i treatment significantly reduces albumin excretion in patients with T2D and microalbuminuria  or macroalbuminuria (UACR >300 mg/g), including patients receiving drugs that block the RAAS ,72,73. AAcute kidney injury (AKI) has been reported in the post-marketing surveillance of patients taking SGLT2is, although a causal relationship has not been established ,11,12,13SGLT2i therapy has diuretic and natriuretic effects in patients with T2D. This results in an approximate 1–2 kg decrease in total body water, a 6% loss in sodium, and a decrease in plasma volume during the first few weeks of treatment ,81,82. HPlasma volume contraction is associated with sustained reductions in systolic/diastolic BP (SBP/DBP) of approximately 5/2 mmHg without a compensatory increase in heart rate and no evidence of orthostatic hypotension ,83,84,85The diuretic effects of SGLT2is differ from those of thiazide or loop diuretics. SGLT2is do not affect plasma osmolality or reduce intravascular volume. Despite having less potent natriuretic and diuretic effects than a loop diuretic, dapagliflozin produced greater reductions in interstitial fluid volume than in blood volume . This maIn patients with HFrEF, the natriuretic effects of SGLT2is are synergistic with loop diuretics and allow for reductions in the dose of loop diuretics ,90. For SGLT2i treatment decreases sympathetic nervous system (SNS) activity (discussed later in this review), which is accompanied by reductions in central SBP, pulse pressure, mean arterial pressure (MAP), the double product (SBP multiplied by heart rate), and aortic pulse wave velocity, which are indications of reduced arterial stiffness and surrogates of afterload ,92,93. IHyperkalemia is common in patients with HF, is associated with specific risk factors including comorbidities such as CKD and T2D and drugs such as mineralocorticoid antagonists and RAAS inhibitors , and incIn patients with T2D and a history of CVD, SGLT2is reduce LV mass index and end-diastolic volume ,103. In Ventricular arrhythmias are common among patients with HFrEF, resulting from chamber dilatation and cardiomyocyte stretch, and may lead to sudden death. A post hoc analysis of the DAPA-HF study, which included patients with HFrEF both with and without T2D, showed that the addition of dapagliflozin to standard therapy for HF was associated with a 21% reduction in the risk of any ventricular arrhythmia, resuscitated cardiac arrest, or sudden death relative to the placebo plus standard therapy . The redChronic activation of the SNS is prevalent in patients with T2D, ischemic heart disease, HF, hypertension, and CKD and results in fluid retention, endothelial dysfunction, and increased arterial stiffness ; chronicThere is evidence that SGLT2is inhibit SNS activation by suppressing renal afferent signaling to the brain and central reflex mechanisms . DapagliTreatment with an SGLT2i is associated with improvements in hemoglobin, hematocrit, and erythropoietin levels. For example, in a short-term study in patients with T2D, serum erythropoietin levels and reticulocyte counts increased over the first 4 weeks of treatment with dapagliflozin, whereas increases in hematocrit, hemoglobin, and red cell mass were sustained over 12 weeks and were all significant when compared with those with a placebo or hydrochlorothiazide . Significantly higher hematocrit and hemoglobin levels were observed over a median of 2.6 years of follow-up in patients with T2D and CKD in CREDENCE , over 20In patients with HFrEF enrolled in DAPA-HF, dapagliflozin treatment was associated with increases in hematocrit that plateaued after 4 months and were sustained for up to 2 years, regardless of T2D status , diuretiThe mechanism underlying these improvements has not been fully elucidated; however, given the weak diuretic effect of SGLT2is and the sustained nature of these hematologic changes, it seems likely that factors in addition to hemoconcentration are involved ,125,127.There is evidence that SGLT2is increase erythropoiesis by modulating iron regulatory proteins ,129. ForImproving hematologic status enhances the delivery of oxygen to tissues and may in part explain reductions in cardiovascular death in patients treated with SGLT2is ,130,131.2 [Hyperuricemia increases oxidative stress, impairs endothelial function, activates the RAAS, and is associated with an increased risk of hypertension, CVD, and CKD. Treatment with an SGLT2i is associated with sustained reductions in serum uric acid levels in patients with T2D ,133,134 Uric acid is not transported by SGLT2 , and SGLIn patients with HFrEF enrolled in EMPEROR-HF, treatment with an SGLT2i was associated with more rapid reductions in serum uric acid levels than those with placebo treatment, which were reflected in a lower incidence of hyperuricemic events  . MoreoveModulation of intracellular sodium through inhibition of the sodium–hydrogen exchanger (NHE) in both the kidneys and the myocardium may contribute to the cardiovascular and renal benefits of SGLT2i therapy ,139. PatCardiovascular and renal complications in patients with T2D are significantly driven by chronic low-grade inflammation mediated by the NOD-like receptor pyrin domain-containing protein 3 inflammasome and oxidative stress . SGLT2isSGLT2is reduce inflammation and oxidative stress in vitro and in animal models ,148,149.Short-term treatment with an SGLT2i significantly decreased platelet reactivity in patients with stable coronary artery disease and T2D who were receiving dual antiplatelet therapy (aspirin plus clopidogrel) in the open-label EFFECT (empagliflozin)  and EDGEIt is hypothesized that alterations in lipolysis and ketone metabolism and the renal handling of ketone bodies may contribute to the cardio- and reno-protective effects of SGLT2is . SGLT2i-The fasting-like metabolic environment and production of ketone bodies may also contribute to rare cases of euglycemic diabetic ketoacidosis during treatment with SGLT2is. The incidence of this complication was similar or lower in patients treated with an SGLT2i than that in patients receiving a placebo in several cardiovascular and renal outcome trials, including EMPEROR-Reduced , EMPERORIn patients with and without T2D, SGLT2is confer cardiovascular and renal benefits that result from complex pharmacological mechanisms. These include effects that are independent of their blood glucose-lowering activity. Enhanced tubuloglomerular feedback plays a central role in protecting the kidney and attenuating the decline in GFR and progression of albuminuria. The link between inhibition of SGLT2 in the kidney and reductions in clinical outcomes  is multifactorial and involves diverse elements, including the inhibition of central SNS outflow and improved hemodynamics. Although initially developed as antihyperglycemic agents, SGLT2is play an increasingly important role in the management of HF and CKD that extends beyond the treatment of T2D.


Systolic and diastolic blood pressure measurements were obtained retrospectively from clinical records. Non-amyloid small vessel disease and cerebral amyloid angiopathy were scored semiquantitatively. Amyloid-β and tau loads were assessed by field fraction measurement in immunolabelled sections of frontal and parietal lobes. Homogenates of frozen tissue from the contralateral frontal and parietal lobes (cortex and white matter) were used to measure markers of vascular function by enzyme-linked immunosorbent assay. Diastolic (but not systolic) blood pressure was associated with the preservation of cerebral oxygenation, correlating positively with the ratio of myelin-associated glycoprotein to proteolipid protein-1 and negatively with vascular endothelial growth factor-A in both the frontal and parietal cortices. Diastolic blood pressure correlated negatively with parenchymal amyloid-β in the parietal cortex. In dementia cases, elevated late-life diastolic blood pressure was associated with more severe arteriolosclerosis and cerebral amyloid angiopathy, and diastolic blood pressure correlated positively with parenchymal fibrinogen, indicating blood–brain barrier breakdown in both regions of the cortex. Systolic blood pressure was related to lower platelet-derived growth factor receptor β in controls in the frontal cortex and in dementia cases in the superficial white matter. We found no association between blood pressure and tau. Our findings demonstrate a complex relationship between late-life blood pressure, disease pathology and vascular function in dementia. We suggest that hypertension helps to reduce cerebral ischaemia (and may slow amyloid-β accumulation) in the face of increasing cerebral vascular resistance, but exacerbates vascular pathology.Hypertension in midlife contributes to cognitive decline and is a modifiable risk factor for dementia. The relationship between late-life hypertension and dementia is less clear. We have investigated the relationship of blood pressure and hypertensive status during late life (after 65 years) to post-mortem markers of Alzheimer’s disease (amyloid-β and tau loads); arteriolosclerosis and cerebral amyloid angiopathy; and to biochemical measures of ante-mortem cerebral oxygenation ; blood–brain barrier damage ; and pericyte content , in Alzheimer’s disease , vascular function and Alzheimer’s disease pathology. High blood pressure in late life may help to maintain brain perfusion and oxygenation and reduce amyloid-β plaque at the expense of increased arteriolosclerosis and blood–brain barrier damage.Tayler https://doi.org/10.1093/braincomms/fcad127) for a scientific commentary on this article.See Magaki and Vinters (  The Honolulu-Asia study found a robust association between midlife hypertension (≥160/95 mmHg) at 45–68 years and clinical diagnosis of vascular dementia and Alzheimer’s disease in late life.7 Sustained hypertension in midlife is associated with increased small vessel disease, white matter (WM) hyperintensities,8 cerebral microinfarcts9 and reduced brain volume.10–12 The burden of cerebral small vessel disease increases with the duration of hypertension.13 Sustained high BP in midlife causes structural and functional cerebral vascular changes that, over time, increase the risk of inadequate perfusion of the brain, cognitive decline and dementia (reviewed14). Blood–brain barrier (BBB) leakiness, endothelial injury and impaired neurovascular coupling, due in part to pericyte damage, are probable early contributors to the onset of small vessel disease and cognitive decline.15Hypertension is also a strong risk factor for stroke, which is itself responsible for cognitive impairment and dementia in 15–70% of survivors.1 Similar findings were reported in other studies.17 Elevated midlife DBP was associated with higher plasma Aβ in the Honolulu-Asia study.18 Another study found a U-shaped relationship between midlife SBP (but not DBP) and plaque density.19 We previously reported that Aβ plaque load was increased in hypertensive subjects.20 The Systolic Blood Pressure Intervention Trial - Memory and Cognition IN Decreased Hypertension (SPRINT MIND) clinical trial  found that intensive versus standard control of BP (SBP < 120 versus < 140 mmHg) did not significantly lower the rate of probable dementia but was associated with a reduced risk of mild cognitive impairment.21 However, that trial covered a wide age range, from 50 years upwards (28.2% of participants were ≥75 years).Elevated midlife BP may also be associated with increased amyloid-β (Aβ) and tau pathology in Alzheimer’s disease. In the Honolulu-Asia aging study, elevated systolic BP (SBP) (≥160 mmHg) was associated with increased cortical and hippocampal neuritic plaque load and elevated diastolic BP (DBP) (≥95 mmHg) with an increase in neurofibrillary tangles.et al.22 found an association between mean late-life SBP (but not DBP) and tangle but not plaque pathology. In some studies, late-life hypertension did not influence the risk of cognitive decline and Alzheimer’s disease23–25; in others, higher SBP, lower DBP and higher BP variability were all associated with higher dementia risk.26–29 Verghese et al.30 reported that elevated BP was protective against dementia in those over 70. Several large longitudinal studies have documented a decline in BP in the years immediately preceding dementia. In middle-aged women over 37 years (n = 707), SBP declined more steeply over a 5-year period in those who developed dementia than in those who did not.31 Steep declines in BP preceding onset of dementia or clinical diagnosis of Alzheimer’s disease were also observed in the Kungsholmen project33 and in those over 78 years in the Adult Changes in Thought Study (n = 2356).34 Cheng et al.35 calculated that the risk of developing dementia was highest when hypertension was ‘stabilized’ and lowest in participants with normal BP who developed hypertension over the 6-year study period. In very late life, hypertension is protective against dementia.37 Although in several studies the treatment of hypertension in midlife reduced the long-term risk or progression of dementia,39 in frail or elderly patients, particularly if already cognitively impaired, lowering SBP below 130 mmHg was associated with increased mortality.40The relationship of late-life hypertension to dementia and its associated pathologies is less clear-cut. Arvanitakis In the present study, the objectives were to better understand the complex interactions between late-life BP and markers of Alzheimer’s disease and vascular pathology in a large pathological study. We have used a combination of histological and biochemical methods to analyse the relationships between late-life (after 65 years) SBP and DBP, Alzheimer’s disease pathology (Aβ and tau), non-amyloid small vessel disease (arteriolosclerosis) and cerebral amyloid angiopathy, and markers of cerebral vascular function: ante-mortem cerebral oxygenation [vascular endothelial growth factor-A (VEGF-A) and myelin-associated glycoprotein:proteolipid protein-1 (MAG:PLP1)], BBB integrity [fibrinogen (FGA)] and pericyte content [platelet-derived growth factor receptor β (PDGFRB)].Post-mortem human brain tissue was obtained from the South West Dementia Brain Bank (SWDBB), University of Bristol, UK. The study was approved by the management committee of the SWDBB (Human Tissue Authority licence number 12273) under the terms of Bristol Research Ethics Committee approval (18/SW/0029). The right cerebral hemisphere had previously been fixed in buffered formalin for 3 weeks and was used for pathological assessment. The left cerebral hemisphere had been sliced and frozen at −80°C. The frontal cortex (FC) (Brodmann area 6) and superficial underlying WM and parietal cortex (PC) (Brodmann area 7) and superficial underlying WM were used in this study. Most of the brains had been dissected within 72 h of death .n = 100) were from donors with no history of dementia, few or absent neuritic plaques, a Braak tangle stage of III or less and no other neuropathological abnormalities. The Alzheimer’s disease cases (n = 75) had a clinical diagnosis of dementia made during life and either intermediate or high Alzheimer’s disease neuropathological change according to the National Institute on Aging - Alzheimer’s Association (NIA-AA) guidelines.41 The vascular dementia cases (n = 20) had a clinical history of dementia with histopathological evidence of multiple infarcts/ischaemic lesions and moderate to severe atheroma and/or arteriosclerosis and only occasional neuritic plaques. The Alzheimer’s/vascular mixed dementia cases (n = 31) had multiple infarcts/ischaemic lesions and moderate to severe atheroma and/or arteriosclerosis but also fulfilled the criteria for Alzheimer’s disease.The age-matched control brains  from all available BP measurements between the age of 65 and 5 years prior to diagnosis. All brain donations to the SWDBB were considered at the time of case selection (2016) and included if (i) the neuropathological criteria were met; (ii) there were clinical data available from National Health Service (NHS) records obtained post-mortem (i.e. BP readings); and (iii) frozen tissue from the selected brain regions was available. The demographic and clinical features of the cohort are shown in 42 and based on the method of Olichney et al.43Cerebral amyloid angiopathy scores were determined in pan-Aβ (4G8) antibody-labelled paraffin sections of frontal and parietal lobes . Cerebral amyloid angiopathy scores (0–3) represent the extent of amyloid deposition in the cerebral vessels, from none to severe, as previously reported44The severity of arteriolosclerosis was scored in haematoxylin- and eosin-stained paraffin sections of frontal and parietal lobes. The scores were based on the level of arteriolar vessel wall thickening and associated luminal narrowing in the subcortical WM, on a 0–3 scale representing none, mild, moderate and severe disease, as previously reported.45 antibody (1:8000) or an AT8 phospho-tau46 antibody (1:500). Field fraction analysis of the area of section immunopositive for the relevant antigen was performed using image analysis software , as previously reported.42Parenchymal Aβ and phospho-tau loads were determined in formalin-fixed paraffin-embedded sections of FC and PC, labelled by a standard 3,3′-diaminobenzidine (DAB) horseradish peroxidase method in a Ventana BenchMark ULTRA automated immunostainer , with either a pan-Aβ 4G8Brain tissue samples were diluted 20% w/v in 1% sodium dodecyl sulphate (SDS) lysis buffer  and homogenized with 5–10 silica beads (2.3 mm diameter) in a Precellys homogenizer (2 × 15 s at 6000 rpm). Homogenates were aliquoted and stored at −80°C prior to use. All subsequent biochemical assays were conducted blinded to the clinical and pathological variables.47–50 Aβ40 and Aβ42 were measured by sandwich enzyme-linked immunosorbent assay (ELISA)  according to the manufacturer’s instructions. Assays on cortical brain homogenates were performed at a 1:4000 dilution and on WM homogenates at 1:2500.Insoluble (guanidine-extracted) tissue homogenates were prepared as previously described.51The concentration of MAG was determined by in-house direct ELISA and the concentration of PLP1 by sandwich ELISA , as previously described.47–49The VEGF-A level was measured by sandwich ELISA  as in our previous studies.49). To allow comparison of parenchymal FGA (i.e. to adjust for blood content), we also measured haemoglobin (Hb) levels by colorimetric assay , in a modified 384-well format, at a 1:10 dilution in triplicate, as previously described.42 Sample Hb content was interpolated from the linear standard (0.016–0.4 g/dl). The FGA level was adjusted for Hb in each sample relative to a mean adult blood Hb of 14 g/dl , although in practice this had minimal impact on the data.FGA was measured by sandwich ELISA  according to the manufacturer’s instructions , as previously.Statistical analyses and graphs were produced using either GraphPad Prism  or Stata . All data sets were assessed for normality of distribution and, if not normally distributed, were either log-transformed or analysed by a non-parametric test, as appropriate. The statistical tests used are indicated in the text.P = 0.0006) than the controls. Gender distribution was evenly distributed across controls, Alzheimer’s disease and vascular dementia groups. The mixed dementia group included proportionately more females, but the difference was not statistically significant (χ2 (df 3) = 5.6697, P = 0.129). The groups were matched approximately for post-mortem delay. The age of dementia onset and duration of disease are shown in P = 0.0055) and the duration of dementia shortest in vascular dementia cases .We studied 226 cases: 75 Alzheimer’s disease, 20 vascular dementia, 31 mixed Alzheimer’s disease/vascular dementia and 100 age-matched controls. The age at death differed slightly between the groups : Alzheimer’s disease cases were younger  = 4.97, P = 0.0023 with 2R of 0.0529)  = 3.27, P = 0.0072; P < 0.001 and P = 0.021, respectively; n = 137; P = 0.047), mixed dementia (P < 0.001) and vascular dementia cases (P = 0.013) and SBP was also higher in vascular dementia cases (P = 0.037), although it should be noted that the small size of the ‘pure’ vascular dementia cohort limits the power of this last subgroup analysis (Mean SBP and DBP and interquartile range (IQR) values for each group are presented in  0.0529) : model 1analysis : model 2P = 0.001; parietal arteriolosclerosis score point 1.05, 95% CI 1.02–1.09, P = 0.007; P = 0.001; parietal arteriolosclerosis score point 1.02, 95% CI 1.01–1.04, P = 0.010; Donors with dementia and elevated late-life DBP had higher frontal and parietal arteriolosclerosis scores. The effect of higher DBP was significant in an ordered logistic regression model, adjusting for the effects of age and dementia subtype  and PC  but not with SBP  but not controls, MAG:PLP1 in the FC correlated positively with DBP . This correlation was not seen in the FC in dementia cases (ns) or in controls in either brain region (both ns)  but not controls (ns). There was no correlation in the FC in either dementia cases or controls (both ns).In the PC, the FGA level (adjusted for Hb content) correlated positively with late-life DBP in the combined dementia cohort (Pearson’s both ns) . Late-lir = −0.2290, P = 0.0219; In the FC and PC, PDGFRB did not correlate with DBP in either controls or dementia cases all ns; . Late-lir = −0.1821, P = 0.0413; In the frontal and parietal WM, PDGFRB did not correlate with DBP in controls or dementia cases all ns; . Late-li52 Our pathological observations support recent studies showing that elevated BP in late life may be protective against Alzheimer’s disease.26–30In this study, we have investigated the relationship between late-life BP and markers of disease and cerebral vascular pathology and dysfunction in people with dementia. We have found late-life BP to be associated with lower parenchymal Aβ load and with biochemical markers of lower ischaemic damage of the cerebral cortex, i.e. may be protective against cerebral hypoperfusion and Aβ accumulation. The relationship between BP and dementia risk is complex. A recent Mendelian randomization study using UK Biobank data found that high BP was associated with reduced late-life risk of developing Alzheimer’s disease.Our study has weaknesses. The repeated BP measurements were obtained retrospectively from clinical records. Fewer BP measurements were recorded in dementia cases. In addition, changes in the diagnosis and management of hypertension between 1985 and 2019, the period during which the brains for this study were donated, are likely to have impacted the frequency of BP recordings in some cases. A strength of this study is that we have collected all available data from clinical records and used the average of many late-life BP measurements for each individual in our analyses. Generally, in our cohort, BP was monitored more regularly, and hypertension was treated more often for the more recent donations. Some of the regression modelling for this study was limited by the small number of cases in each group, particularly since there were few pure vascular dementia cases, which limited the statistical power of our analyses. We also noted some moderate differences in the average age of the groups. We included age and disease subtype as covariates in our regression modelling partly because of the known associations with arteriolosclerosis and cerebral vascular function.22 Previous studies demonstrated that longer-term exposure to hypertension strengthened the association with cerebral small vessel disease burden.13 Higher late-life BP was also associated with an increased number of brain infarcts, and exposure to vascular risk factors, including hypertension, adversely affected WM integrity.53 Muller et al.54 found an association between higher late-life BP and increased risk of WM lesions and cerebral microbleeds in older participants; the effect was most pronounced in those without a history of midlife hypertension.We found that elevated DBP was associated with more severe arteriolosclerosis in dementia cases. This is in keeping with evidence of a relationship between the severity of arteriolosclerosis and DBP.56 However, arterial hypertension is a frequent comorbidity in people with clinically diagnosed cerebral amyloid angiopathy57 and has been shown to interact with severe cerebral amyloid angiopathy to increase the risk of infarction.58 In Tg2576 mice, Aβ pathology promoted hypertension-induced intracerebral haemorrhage,59 and BP-lowering strategies were suggested as a means to reduce the risk of recurrent cerebral amyloid angiopathy-associated intracerebral haemorrhage.61 However, another study found that hypertensive cerebral amyloid angiopathy patients had lower mortality than normotensive patients.62 In hypertensive rats, severe small vessel disease promoted the development of cerebral amyloid angiopathy.63In the frontal lobe, the severity of cerebral amyloid angiopathy correlated with SBP. Other neuropathological studies did not find SBP to be associated with cerebral amyloid angiopathy severity.65 Cerebroventricular infusion of Aβ40 in rats significantly elevated BP and exacerbated existing hypertension, probably via modulation of autonomic activity.66 In cognitively normal elderly individuals, Aβ deposition (measured by florbetapir-Aβ PET) and WM hyperintensity volume both affected rates of neurodegeneration, but these effects were independent with no evidence of interaction.67 Both arteriolosclerosis and cerebral amyloid angiopathy lead to luminal narrowing and increased cerebral vascular resistance, which puts the brain at risk of hypoperfusion. An elevation in BP in response to these vascular alterations may be a physiological adaptation that allows the brain to maintain cerebral perfusion (and maintain clearance of Aβ).68 The late-life decline in BP that often precedes the onset of dementia may reflect the decompensation of these adaptive mechanisms for maintaining cerebral perfusion (perhaps contributing to Aβ accumulation).Observational studies have shown that elevated SBP may be protective in older individuals and may be induced as a response to a decline in brain vascular health.69 and vascular mild-cognitive impairment70 and underpin the development of small vessel disease.71 We recently found that BBB breakdown was elevated in controls and dementia cases with terminal systemic infection72 and that BBB damage was more severe in mixed vascular/Alzheimer’s dementia than in pure Alzheimer’s or vascular dementia cases.42 In the present study, FGA levels correlated positively with DBP, in keeping with other evidence of a link between hypertension and BBB damage.73–75 Dysfunction of the BBB is likely to be but one manifestation of hypertensive vessel wall damage that impairs the clearance of metabolites and impacts Aβ accumulation in Alzheimer’s disease. Damage to pericytes probably contributes to BBB damage in the early stages of Alzheimer’s disease.76 Here, we show that elevated SBP was inversely related to PDGFRB content in the FC in controls and in the superficial WM in Alzheimer’s disease.Damage and leakiness of the BBB are associated with cognitive decline in the early stages of Alzheimer’s disease1 Our findings also suggest that high BP in late life may protect against some other Alzheimer’s disease-associated changes, including chronic cerebral hypoperfusion. This is evidenced by the higher MAG:PLP1 ratio  in brain donors with a history of elevated late-life DBP and the lower levels of VEGF-A.47 We previously showed that cerebral hypoperfusion in Alzheimer’s disease is due in part to elevated expression of potent vasoconstrictors, including endothelin-179 and angiotensin-II.81 Aβ peptides themselves have direct and indirect vasoconstrictor actions.82–85 In contrast, we found no evidence of a relationship between DBP and tangle pathology. This supports previous data.22In the present study, we have shown that elevated DBP in individuals aged 65 years and over correlated negatively with parenchymal Aβ load, specifically in the PC. This contrasts with previous reports of a positive relationship between hypertension and elevated parenchymal Aβ and tau; however, participants in those studies had midlife hypertension.In conclusion, there is a complex relationship between late-life BP and markers of vascular and Alzheimer’s disease pathology in dementia. Elevated late-life DBP is associated with biochemical markers, which indicate lower ischaemia and less accumulation of Aβ, but also with more severe vascular damage, including arteriolosclerosis, cerebral amyloid angiopathy, BBB breakdown and pericyte loss. Late-life elevated BP may be a physiological response to maintain cerebral oxygenation in response to increased cerebral vascular resistance—an adaptation that maintains cerebral blood flow and Aβ homeostasis but, when sustained over a longer period, exacerbates vascular pathology until eventually BP declines, preceding the onset of clinical disease.fcad112_Supplementary_DataClick here for additional data file.


Effective delirium prevention could benefit from automatic risk stratification of older inpatients using routinely collected clinical data.Primary aim was to develop and validate a delirium prediction model (DELIKT) suitable for implementation in hospitals. Secondary aim was to select an anticholinergic burden scale as a predictor.We used one cohort for model development and another for validation with electronically available data collected within the first 24 h of admission. Included were patients aged ≥ 65, hospitalised ≥ 48 h with no stay > 24 h in an intensive care unit. Predictors, such as administrative and laboratory variables or an anticholinergic burden scale, were selected using a combination of feature selection filter method and forward/backward selection. The final model was based on logistic regression and the DELIKT was derived from the β-coefficients. We report the following performance measures: area under the curve, sensitivity, specificity and odds ratio.Both cohorts were similar and included over 10,000 patients each (mean age 77.6 ± 7.6 years) with 11% experiencing delirium. The model included nine variables: age, medical department, dementia, hemi-/paraplegia, catheterisation, potassium, creatinine, polypharmacy and the anticholinergic burden measured with the Clinician-rated Anticholinergic Scale (CrAS). The external validation yielded an AUC of 0.795. With a cut-off at 20 points in the DELIKT, we received a sensitivity of 79.7%, specificity of 62.3% and an odds ratio of 5.9 .The DELIKT is a potentially automatic tool with predictors from standard care including the CrAS to identify patients at high risk for delirium.The online version contains supplementary material available at 10.1007/s11096-023-01566-0. Routinely collected data within the first 24 h of admission can be integrated into a prevention tool to automatically predict delirium in hospitalised older patients.The cumulative anticholinergic burden measured with the Clinician-rated Anticholinergic Scale is a reversible predictor for incident delirium, thus tailored medication lists with clear alternatives could installed as preventive measures.The DELIKT has the potential to be implemented and tested in a impact study to investigate its clinical effectiveness.Delirium is common in hospitalised older patients, with an incidence rate ranging from 20% to 29% in geriatric units and 11% to 14% in general medical wards . DeliriuDrugs with anticholinergic (ACH) properties are of particular interest, especially in the case of polypharmacy. The prevalence of drug use with ACH activity has nearly doubled over the past two decades . The intAs delirium diagnosis is purely clinical and laboratory tests are lacking, a variety of detection and screening tools have been developed . DespiteWe believe that effective prevention of delirium requires an automated, predictive tool that accurately identifies high-risk patients early after admission, ideally using routinely collected clinical data.Primary aim was to develop and validate a delirium prediction model (DELIKT) suitable for implementation in hospitals. Secondary aim was to select an anticholinergic burden scale as a predictor.The Swiss ethics review committee approved the protocol written for this study .We used electronic health record (EHR) data from the first 24 h after admission for patients hospitalised between January 2015 and December 2018 at a tertiary teaching hospital in Switzerland. The years 2015/2016 were used for development and 2017/2018 for external validation. The cohort selection criteria, outcome definition and predictors are summarised below and have been described elsewhere in more detail .Inclusion criteria were inpatients aged 65 years or older with a length of stay ≥ 48 h and with no stay > 24 h in an intensive care unit (ICU), because the ICU did not use EHRs. Patients experiencing delirium within the first 24 h of hospitalisation or those with delirium related to substance abuse defined by International Classification of Disease 10 (ICD-10) codes were excluded.Delirium during hospitalisation was a binary outcome. It was defined as having an ICD-10 coded diagnosis , a positive result in the Confusion Assessment Method (CAM) or a daily mean score of three points or more in the Delirium Observation Screening Scale (DOSS).Potential predictors were considered from the clinical data warehouse if they fulfilled four criteria: 1) previously identified in the literature including all 19 ABSs published to date  previous; (2) avaWe extracted the following data for each patient from the EHR: demographic and administrative characteristics, diagnoses (ICD-10 codes), laboratory values and medication intake. All variables were dichotomised to facilitate the application of the prediction tool. The cut-offs were set at clinical importance based on a literature review and guidelines –18.Demographic and administrative characteristics were age, sex and the hospital department. Furthermore, comorbidities were identified according to the Charlson comorbidity index based on the ICD-10 codes . The folThe variables from the laboratory and patient chart included glomerular filtration rate (GFR), creatinine (serum), potassium, sodium, C-reactive protein (CRP), body temperature, catheterisation and medication. All drugs administered within the first 24 h of hospitalisation were extracted. Of these, we considered all drugs using the ATC code that had so far been scored by any of the 19 ABSs and calculated a patient’s cumulative ACH burden . Drugs tVariables with values missing in more than 20% of cases were not considered. Among considered variables, missing values were imputed by last observation carried forward. We filled in the overall mean (continuous) or mode  of the variable for each patient, if no value had previously been recorded.t-test for continuous variables with normal distribution and a Mann–Whitney U test in the case of non-normal distributions. The mean ± the standard deviation or the median and interquartile range in the case of non-normal distribution are reported for continuous variables and the numbers with percentages for categorical variables.For data management and analyses, we used the statistical software R  . We perfThe prediction model and DELIKT were developed and trained on the data set from the years 2015/2016. Due to the imbalanced nature of the data set, we used the synthetic minority oversampling technique (SMOTE) with five nearest neighbours on the minority class and a rate of eight on the training set prior to predictor variable selection, using the R package mlr . For intThe final prediction model was used to develop the DELIKT by rounding up the lowest β-coefficient to one, then multiplying the other coefficients by the same factor and finally rounding to the nearest whole number, as reported previously . Next, tWe included 12,052 patients in the development cohort of which 11% developed a delirium (72.0% identified by DOSS) during hospitalisation . The mean age was 77.6 ± 7.6 years, and 51.6% of the patients were female. The validation cohort was comparable to the development cohort. The patient characteristics of the overall population in the development and validation cohort are depicted in Table Of the 42 predictor variables, nine were included in the final model: age, medical department, dementia, hemiplegia/paraplegia, catheterisation, potassium, creatinine, polypharmacy and the ACH burden measured with the Clinician-rated Anticholinergic Scale (CrAS) .The internal and external validation of the prediction model were similar in terms of AUC, 0.792  vs. 0.795 , respectively .We observed a delirium occurrence of 11%, which is at the lower end of the range found in the literature , which dAs of now, multiple delirium risk factors have been identified, which are often grouped into predisposing and precipitating factors . PredispTo our knowledge, this is the first report that includes the cumulative ACH burden measured with an ABS. In our previous publication, three points or more in the Anticholinergic Toxicity Scale (ATS) showed a stronger association with incident delirium compared to the CrAS . The CrATwo predictors that have previously been identified and were not included in our study were vision and hearing impairment . This waWe found four other prediction models for delirium that focused on medical and surgical patients , 37–39. Diagnosis of delirium is difficult due to its fluctuating course. In addition, there are also two different subtypes of delirium (hyperactive vs. hypoactive) . Our DELFor a prospective study using the DELIKT, comorbidity variables must either be assessed using a diagnosis list or asking the patient or be replaced by a surrogate parameter, such as the CRP for infection. Alternatively, machine learning techniques could be used to scan for delirium key words written in a physician’s progress report. Finally, per TRIPOD statement our type of validation is considered “narrow”. Thus, it is highly recommended to perform a “broad” validation, meaning in a different hospital and, if possible, with prospectively collected data.The DELIKT is a potentially automatic tool with predictors from standard care including the CrAS to identify patients at high risk for delirium. A DELIKT score of more than 20 points was significantly associated with incident delirium. It could be implemented in a computerised physician order entry system to automatically predict delirium risk during admission. The cut-off score can be adapted depending on what sensitivity or specificity is warranted. In a next step, the DELIKT or the CrAS alone should be implemented in a clinical station to conduct an impact study evaluating its preventive power in comparison to standard care.Supplementary file 1 (PDF 164 KB)Supplementary file 2 (PDF 164 KB)Supplementary file 3 (DOCX 96 KB)Below is the link to the electronic supplementary material.