The objective of this study was to develop models for predicting the evolution of a neck pain (NP) episode.Three thousand two hundred twenty-five acute and chronic patients seeking care for NP, were recruited consecutively in 47 health care centers. Data on 37 variables were gathered, including gender, age, employment status, duration of pain, intensity of NP and pain referred down to the arm (AP), disability, history of neck surgery, diagnostic procedures undertaken, imaging findings, clinical diagnosis, and treatments used. Three separate multivariable logistic regression models were developed for predicting a clinically relevant improvement in NP, AP and disability at 3 months.Three thousand one (93.5%%) patients attended follow-up. For all the models calibration was good. The area under the ROC curve was ≥0.717 for pain and 0.664 for disability. Factors associated with a better prognosis were: a) For all the outcomes: pain being acute (vs. chronic) and having received neuro-reflexotherapy. b) For NP: nonspecific pain , no signs of disc degeneration on imaging, staying at work, and being female. c) For AP: nonspecific NP and no signs of disc degeneration on imaging. d) For disability: staying at work and no signs of facet joint degeneration on imaging.A prospective registry can be used for developing valid predictive models to quantify the odds that a given patient with NP will experience a clinically relevant improvement. Neck pain (NP) is defined as pain in the neck with or without pain referred into one or both upper limbs (“arm pain” -AP-). Worldwide, the point prevalence of NP is 4.9% (95% CI 4.6 to 5.3), and it is one of the top five chronic pain conditions in terms of prevalence and years lost to disability –3.Most episodes of acute NP improve spontaneously, but more than 30% of patients show some persistent or recurrent symptoms 1 year later . UnfortuData from registries implemented in routine practice could be useful to develop prediction rules factoring in each patient’s personal and clinical characteristics, including treatments received. This would also empower patients for informed shared decision making .Ideally, registries should include virtually all the patients, gather valid, reliable and clinically relevant data, and ensure that losses to follow-up are kept to a minimum. Concerns have been expressed with regard to the feasibility of these requirements in routine clinical practice .Therefore, the objectives of this study were; a) to explore the feasibility of implementing a registry of patients treated for NP in routine practice, b) use it to develop predictive models in order to quantify the likelihood that a given patient experiences a clinically relevant improvement in NP, arm pain and disability, and c) to assess such predictive models.Forty-seven health care centers were selected by the Spanish Back Pain Research Network to be invited to participate in this study, based on their past involvement in research on neck and low back pain. The centers were located across 11 out of the 17 Administrative regions in the country . The population of these regions is 35,776,167, approximately 77% of the total population of the country [Fifteen centers belonged to the Spanish National Health Service (SNHS), 6 to not-for-profit institutions working for the SNHS, and 26 were private. They included 8 primary care centers, 18 physical therapy practices, and 21 specialty Services in rheumatology (5), rehabilitation (6), neuroreflexotherapy (4), and orthopedic surgery (6).The inclusion and exclusion criteria were as follows.Inclusion criteria: a) Seeking care for NP in a participating unit, b) suffering from neck pain, with or without pain in the arm, unrelated to trauma or systemic disease, and c) proficiency in Spanish.Pain unrelated to systemic disease was defined as pain unrelated to cancer or inflammatory disease , in patients who did not present signs suggesting fibromyalgia (defined as diffuse pain with unexplained fatigue or sleep disturbances) or “red flags” for latent systemic diseases. “Red flags” were defined as “oncologic disease during the previous 5 years, constitutional symptoms –unexplained weight loss, fever, chills-, history of intravenous drug use, or immunocompromised host” –11. PatiPatients who were included were asked to sign an informed consent, authorizing the use of demographic and clinical data related to their care for the purpose of this study.Exclusion criteria were: central nervous system disorders (treated or untreated), other causes of referred or radiated pain in the arm  and not having signed the informed consent.In order to analyze the influence of up to 40 variables, the sample had to include at least 400 subjects who would not experience improvement . ApproxiSince this study did not require any changes to standard clinical practice, according to the Spanish law it was not subject to approval by an Institutional Review Board. All procedures followed were in accordance with the ethical standards of the Helsinki Declaration of 1975, as revised in 1983.As per standard practice in Spain, patients and clinicians received no compensation for participating in this study.Patients were recruited consecutively at the participating centers. All patients seeking care for NP were screened for inclusion and exclusion criteria.All patients complying with inclusion criteria were invited to participate, and all those who accepted to sign the informed consent were included. Recruiting clinicians explained to eligible patients the importance of answering fully and accurately a series of questionnaires assessing their clinical status, and complying with the follow-up visit for an assessment of their evolution.Patients were assessed upon recruitment and at follow-up. The follow-up assessment was planned at 3 months because: a) this study sought to analyze the outcome of a single episode of neck pain rather than relapses, b) this timeframe implies that all patients who are symptomatic at follow-up, would be chronic ; c) exisPatients were asked to complete the self-administered questionnaires at both assessments. Questionnaires were completed in private, with no interference from health care personnel or any other actors. Data from the questionnaires were inserted into a database by a team of auxiliary personnel with no connection to the treating physician. In order to make clinical decisions, the treating clinicians had access to that information, but were not able to alter the data. Participating in this study did not imply any changes to patients’ clinical management, and clinicians were instructed to manage their patients as usual.This registry used the same variables and measuring instruments as the only registry of neck and back pain patients available in Spain. The latter was originally developed for post-marketing surveillance of a minimally invasive technology (“neuro-reflexotherapy”), and has shown to be reliable and lead to low proportions of missing data and losses to follow-up , 16, 24.The registry gathered data from patients and from clinicians. Data requested from patients at the first assessment, were: gender, age (date of birth), duration of the current pain episode (date of pain appearance), time elapsed since the first episode (years), and employment status .At both assessments, patients were asked to report pain and disability, which are considered two of the main outcome measures for patients with spinal pain . To thisData requested from recruiting clinicians were: diagnostic procedures prescribed for the current episode , patients’ radiological findings on imaging procedures performed for the current or previous episodes, as reported by radiologists , diagnosis , and treatments undergone by the patient throughout the study . When their distribution departed from normality, median and percentiles 25 and 75 were used.Reductions in VAS or NDI scores between the baseline and follow-up assessments, were considered to reflect improvement only if they were greater than the minimal clinically important change (MCIC). The MCIC for pain and disability has been established as 30% of their baseline scores, with a minimum value of 1.5 for VAS and 7 NDI points for neck pain-related disability , 28. ThiFor instance, it was impossible for a patient with a disability score smaller than the MCIC at baseline to experience improvement in disability, and including this patient’s data into the model exploring factors associated with a clinically relevant improvement in disability could skew results. In the case of patients with baseline scores below the MCIC, lack of improvement could only be spotted if they experienced a worsening of pain or disability . Therefore, in the case of patients with a baseline score which was smaller than the MCIC for a given variable, only those who at discharge had shown to have experienced a worsening were included in the analyses.Outcome measures were neck pain, arm pain and disability. In order to quantify the likelihood that a given patient would experience a clinically relevant improvement in these variables, three separate multivariable predictive logistic regression models were developed. Improvement in NP, AP or disability were the dependent variables, and the maximal models included: gender; age (in years); baseline intensity of NP (VAS points); baseline intensity of AP (VAS points); NP-related disability at baseline (NDI percentage); duration of the current episode in days (number of days); duration of the current episode  ; time elp > 0.05 was used to eliminate variables from the model, following a non-automatic backward strategy. Nomograms were developed to illustrate the results of the models [The value e models .The area under the ROC curve (AUC) was used to asess discrimination of the final models, and calibration was assessed using the Hosmer-Lemeshow test .The selection of variables was validated by using bootstrapping: 100 bootstrap samples were drawn . Sample Both the apparent performance of each bootstrap sample (“bootstrap performance”) and the performance of the bootstrap model in the original sample (“test performance”), were determined. Overfitting was defined as the average difference between bootstrap performance and test performance .The Stata/IC v15.1 was used for statistical analysis.All the 47 health care centers which were invited to participate in this study, accepted. All patients invited to participate in the study, agreed to sign the informed consent. All were included and none were excluded. Due to the multicenter design, when sample size was reached, 3225 patients had been included. The second assessment, which was planned 90 days after the first one, generally took place later , and 224 patients (6.95%) were lost to follow up.Among the 3001 patients who attended the follow-up, most were women (74.2%), the median duration of their pain episode was 180 days, and their baseline median value for pain intensity was 6.6 VAS points for NP and 6.0 for AP, while their mean score for disability in the NDI was 37.2 , 2188 reported some degree of AP, and 1500 reported some degree of disability . Data from 6 patients were excluded from the regression model on NP because their baseline scores were below the threshold required for any potential improvement to be “clinically relevant”. For the same reason, data from 105 and 49 patients were excluded from the regression models on AP and disability, respectively. All the reasons leading to the exclusion of data from the regression models, are shown in Fig. Among the patients included in the corresponding models, 1716 72,3%) showed a clinically relevant improvement in NP at the 3 month assessment and the remaining 656 did not, while 507 patients  showed a clinically relevant improvement in disability and 476 did not . Discrimination of the model was good, with an AUC of 0.718. Overfitting was 0.020.The multivariable logistic regression model showed that the factors which, at baseline, predicted a clinically relevant improvement in NP 3 months later, were, from highest to lowest frequency in bootstrapping validation (Table p = 0.369). Discrimination of the model was good, with an AUC of 0.717. Overfitting was 0.030.Factors predicting a clinically relevant improvement in AP 3 months later, were: being treated with neuro-reflexotherapy, arm pain being more severe, pain being acute (vs. chronic), not showing signs of disc degeneration on imaging, neck pain being less severe, and suffering from “non-specific” pain  Table . The assp = 0.480). Discrimination of the model was poor, with an AUC of 0.664. Overfitting was 0.037.Factors predicting a clinically relevant improvement in disability 3 months later, were: arm pain being less severe, being treated with neuro-reflexotherapy, working , baseline disability being higher, not showing signs of facet joint degeneration on imaging, and pain being acute (vs. chronic) Table . The assFigures Results from this study show that it is feasible to implement a registry for NP patients treated in routine clinical practice. The registry included all patients seeking care for NP in the participating centers, where they were treated following standard practice in routine clinical practice. Clinically relevant data were gathered using previously validated methods , 24–26, However, a registry analysis is an observational study, and “association” does not necessarily imply “causality”. Therefore, results showing the association between a given variable and a better or worse prognosis should be interpreted cautiously, taking clinical plausibility into account. For instance, the association between staying at work and improvement in NP, which is consistent with results from previous studies on NP , 33, migNevertheless, results from this study are in line with those from previous studies and are clinically plausible; most imaging findings are unlikely to predict the clinical evolution of NP, AP or disability, unless there is a correlation between clinical and radiological findings ; radiculIt is likely that the evolution of disability is affected by additional variables which were not assessed in this registry. In fact, discrimination was good in the models on NP and AP, whereas it was poor in the model on disability. Additionally, baseline mean score for disability was mild, and in a significant number of patients it was below the value of the minimal clinically important change. As a result, the model on disability only included data from approximately 40% of the patients. Despite all of the above, for all models discrimination was > 0.663 and calibration was acceptable, which suggests that nomograms may be applicable in clinical practice for early identification of patients who are at a higher risk of becoming chronic.Many different treatment modalities are used for the treatment of NP, but very few are supported by solid evidence on efficacy or effectiveness deriving from high quality randomized controlled trials (RCTs) , 35–49. Registries cannot substitute RCTs, and are not valid for proving the efficacy or effectiveness of treatments. However, they can be useful to assess the prognostic value of procedures which have previously shown to be efficacious through appropriate randomized clinical trials, or are assumed to be effective based on the evidence on their effect in other types of spinal pain. None of the pharmacological groups which were analyzed in this study was associated with clinical improvement. This might be due to the fact that, for the treatment of patients with NP, drugs are essentially designed to offer symptomatic pain relief, while this study focused on the improvement of the pain episode at 3 months. For the same reason, the timeframe of this study may be inappropriate to capture the effect of treatments aiming to prevent relapse or requiring longer periods to have an effect, such as exercise or surgery.Previous studies and systematic reviews on prognosis factors for neck pain vary substantially in design and setting, and methodological shortcomings have led to uncertainty about the reliability of the prognostic factors which have been suggested . In factThe representativeness of the sample does not appear to be a major concern; recruiting centers were spread over 11 out of the 17 administrative regions existing in Spain, they included state-owned  and private practices , and they included primary care, physical therapy and specialty centers. All patients seeking care in these practices were screened consecutively, all those who complied with inclusion criteria were included, none were excluded, losses to follow-up were below 7%, and patients’ characteristics are in line with the typical patient requesting care for neck pain  cases. As a result, the sample included both patients with acute pain and those with (exacerbations of) chronic pain. The proportion of acute and chronic patients might have been different if the proportion of primary and specialty centers had been different.Should the study have been conducted in a different setting, the proportion of patients receiving each form of treatment might also have been different. In fact, this study did not gather any data on the rationale for prescribing a specific treatment to a given patient. Therefore, such a rationale and how strictly the clinicians involved in this study followed indication criteria for each treatment, are unknown. However, this is usual in routine practice, and this study did not aim to assess the therapeutic effect of any treatments in experimental conditions, but their prognostic value in routine practice. Moreover, this study included a broad array of patients, recruited in both primary and specialty care centers, and the analysis made it possible to assess the association between each one of their characteristics and their prognosis for pain and disability. Future studies should explore the generalizability of these models to other cultural contexts.In Spain, especially within the Government run health system , patients are first seen by a primary care physician, who acts as a “gatekeeper”, checks for the presence of “red flags” and refers patients with indication criteria for a specialized treatment to the appropriate specialist. Therefore, some treatments are almost exclusively applied in Services specialized in that given treatment . This implies that, in this study, the prognostic value of being treated in one or other Service could not be explored because multicolinearity was detected between “treatment received” and “specialty”. The prognostic value of the type of clinician who treats the patient should be explored in further studies, especially if conducted in settings where patients with neck pain are the main decision makers when deciding on the type of clinician they chose to seek care from.Losses to follow up beyond 3 months in this register are unknown and should be assessed in further studies. This study focused on the clinical prognosis of a single NP episode, and analyzing factors associated with relapses was not within its scope and would require longer follow-up periods.The health care centers invited to join this study were selected because of their previous involvement in research on spinal pain, and are not a random sample of health care centers. As a result, no neurosurgery practice was included in the sample, and participating clinicians may be more evidence-based in their practice than average, or more positively predisposed than average for implementing a registry on NP. Nevertheless, these centers represented a feasible and adequate platform to test run this registry in the context of routine practice, although It may be more difficult to implement registries in environments where the clinical community is less accustomed to e-health.This registry did not include any psychological variables. This is due to the fact that, to date, the only psychological variables potentially influencing the prognosis of spinal pain which have been assessed in the Spanish cultural setting are fear avoidance beliefs and catastrophizing, and their influence has shown to be clinically irrelevant or null , 21, 50.Results from this study suggest that the probability that a patient with neck pain will experience improvements in neck pain, arm pain and disability within a 3 months period, can be quantified using the following data; baseline scores for neck pain, arm pain and disability, whether neck pain is acute or chronic, whether it is “nonspecific” , whether the patient is male or female, whether he/she is treated with neuro-reflexotherapy, whether he/she stays at work , and whether he/she shows some specific images on MRI.


Sickle cell disease (SCD) is an inherited red blood cell disorder affecting millions worldwide, and it results in many potential medical complications throughout the life course. The hallmark of SCD is pain. Many patients experience daily chronic pain as well as intermittent, unpredictable acute vaso-occlusive painful episodes called pain crises. These pain crises often require acute medical care through the day hospital or emergency department. Following presentation, a number of these patients are subsequently admitted with continued efforts of treatment focused on palliative pain control and hydration for management. Mitigating pain crises is challenging for both the patients and their providers, given the perceived unpredictability and subjective nature of pain.The objective of this study was to show the feasibility of using objective, physiologic measurements obtained from a wearable device during an acute pain crisis to predict patient-reported pain scores (in an app and to nursing staff) using machine learning techniques.Technology Resources to Understand Pain Assessment in Patients with Pain, and those obtained by nursing staff were both used with wearable signals to complete time stamp matching and feature extraction and selection. Following this, we constructed regression and classification machine learning algorithms to build between-subject pain prediction models.For this feasibility study, we enrolled 27 adult patients presenting to the day hospital with acute pain. At the beginning of pain treatment, each participant was given a wearable device (Microsoft Band 2) that collected physiologic measurements. Pain scores from our mobile app, Patients were monitored for an average of 3.79 (SD 2.23) hours, with an average of 5826 (SD 2667) objective data values per patient. As expected, we found that pain scores and heart rate decreased for most patients during the course of their stay. Using the wearable sensor data and pain scores, we were able to create a regression model to predict subjective pain scores with a root mean square error of 1.430 and correlation between observations and predictions of 0.706. Furthermore, we verified the hypothesis that the regression model outperformed the classification model by comparing the performances of the support vector machines (SVM) and the SVM for regression.The Microsoft Band 2 allowed easy collection of objective, physiologic markers during an acute pain crisis in adults with SCD. Features can be extracted from these data signals and matched with pain scores. Machine learning models can then use these features to feasibly predict patient pain scores. Sickle cell disease (SCD) is a hematologic disorder that can cause a multitude of complications throughout a patient’s life, with pain being the most common and a significant cause of morbidity. The pain experienced by SCD patients is often chronic with acute vaso-occlusive crises that are unpredictable and lead to frequent visits to the emergency department (ED) and day hospital for management . Of thesIn the last several years, there has been an increasing focus on developing and implementing individualized pain plans . HoweverMore recently, technology has been leveraged to use mobile apps for recording symptoms in real time and wearable devices to provide more frequent physiologic measurements. The field of mobile health  has continued to grow and has been used in a variety of different clinical settings. Many studies have attempted to help patients and providers connect using mobile technology to better understand and treat a multitude of symptoms, including pain -6. Many We previously reported the usefulness and validity of our mHealth app for patients with SCD -9. The aIn the face of the continued opioid crisis, the search for more objective measures of pain continues to rapidly evolve in medicine, and studies looking at a variety of objective measures to predict pain have been published in recent years. Among these studies, the types of objective data utilized to predict pain vary in invasiveness  but show promise for utilizing such data to predict pain. Bendall et al  examinedOwing to the growing volume of clinical data and the requirement of high accuracy predictive models, machine learning techniques have been increasingly utilized in medicine. They have been applied to multiple health care domains, from analgesic response prediction to postoperative pain estimation -15. MachWe now aim to use physiologic data obtained from a wearable device matched with mobile app and nurse-obtained pain scores to predict pain scores at between-subject level using machine learning techniques. The combination of mobile apps and wearable sensors has been used in several studies to provide novel solutions to different health problems -22. To dFollowing Duke Institutional Review Board approval, patients presenting for acute pain crisis to the day hospital were approached and asked to participate in the study. A convenience sample of eligible patients who were willing to participate was consented. A small number of patients approached declined to participate, but this specific number was not recorded, and no patients withdrew from the study after consent. Of the 27 patients consented, 20 were included in this study because of insufficient data from the wearable device in 7 patients. Patients were consented Monday through Friday based on the availability of study team members. Study duration was variable based on patient’s length of stay in the day hospital. The study included a one-time visit only. Patients might have had other chronic medical conditions but were not excluded based on these conditions, and subgroup analysis was not undertaken.Following consent, a Microsoft Band 2 wearable was placed on the patient’s wrist. The Microsoft Band 2 is a commercially available smart band that is compatible with many smartphones; it has multiple objective sensors including HR monitor, a 3-axis accelerometer and gyrometer, a GSR sensor, and a skin temperature sensor. The physiologic and activity measures utilized in the study are shown in Patients were also provided with an iPad with the TRU-Pain app to record pain scores and other symptoms in conjunction with nurse-reported pain scores using a visual analog scale from 0 (none) to 10 (worst). Each patient was instructed on the use of the TRU-Pain app. The TRU-Pain app allowed patients to use a slider bar to rate their pain on the visual analog scale from 0 to 10. The app also allowed patients to note other symptoms and rate general health and mood . The TRU-Pain app implemented these general health and mood measures and a platform upgrade to AppleCare Kit, replacing our previous app, Sickle Cell Disease Mobile Applications to Record Symptoms via Technology. Nursing pain scores were assumed to be entered at the time they were obtained.Both objective data from the Microsoft Band 2 and the TRU-Pain app were uploaded to a Health Insurance Portability and Accountability Act–compliant Citrix ShareFile cloud-based server. Patients were continuously monitored while in the day hospital, and at the time of discharge, the devices were returned. If patients were admitted, data before transfer were included even if the devices traveled with the patient during admission. Patients were not provided specific questions regarding acceptability and feasibility of participation, but the feasibility of the study was determined by the accuracy of machine learning algorithms in predicting pain scores.Heart rateR-R intervalGalvanic skin responseSkin temperatureAcceleration in X directionAcceleration in Y directionAcceleration in Z directionAngular velocity in X directionAngular velocity in Y directionAngular velocity in Z directionStepsTo apply machine learning analysis on the collected wearable sensor data  period. However, a sample size of 40 was not sufficient for the intended data analysis. To further increase the sample size, we included nurse-documented pain scores in our dataset. Our group made the assumption that nurse-documented scores were similar to patient-reported scores in the app. Nurse-documented pain scores were matched with wearable sensor data using the within 10-min time stamps methodology as described above. By including nurse-documented pain scores, our final dataset contained 107 data samples (40 mobile app and 67 nursing notes).After time stamp matching, each pain score was mapped to a 1-min long wearable sensor data segment that included 8 signals as mentioned in The feature extraction yielded up to total 64 (8×8) features. Given the relatively small sample size (107), a feature selection method was applied (wrapper method) to remove irrelevant or redundant features and to further reduce the number of features . The wraThe prediction of numeric pain score, the main study outcome, can be treated as either a regression problem or a classification problem. As the pain scores from app data are float numbers, it is more reasonable to build a regression model to provide continuous estimation of the target variable. More importantly, there is only 1 target variable (pain score) in the regression model. In contrast, there will be 11 classes if pain is treated as a classification problem, as there are 11 distinct possible pain scores (0 to 10). The number of classes can be reduced by employing a sparse rating scale. Using a widely adopted more sparse 4-point rating scale, the 11-point pain scores can be categorized as none (0), mild (1-3), moderate (4-6), and severe (7-10) . HoweverFor linear models, we utilized Ridge and Lasso ,33. LineA total of 20 adult patients (of 27 consented) had complete data. Median age was 28 years, with a range of 20 years to 66 years . A totalPatients presenting to the day hospital often receive intravenous fluids, antiemetics, NSAIDs, and opioids. The opioid doses received during their day hospital stay are shown in A total of 4 regression algorithms were implemented on 2 reduced feature sets. Results were validated using 10-fold cross-validation. Moreover, 2 evaluation metrics were applied to evaluate the performance of algorithms—the root mean square error (RMSE) and Pearson correlation . RMSE isFor the dataset in our study, the standard deviation of 107 pain scores is 2.013, which can be interpreted as the RMSE of using the mean value as the predicted pain values. All the regression models obtained RMSE lower than the mean-only model. With 10 features in the forward selection feature set, the SVR had the best performance as the RMSE of 1.721 and the correlation of 0.522, followed by the GPR obtaining the RMSE of 1.764 and the correlation of 0.475. These results demonstrate the feasibility of using objective wearable sensor measurements to estimate subjective pain scores. With 14 features in the backward elimination feature set, the performance of GPR and SVR is further improved. The SVR model is slightly superior to the GPR model, with an RMSE of 1.430 and correlation of 0.706, respectively, which are also the best performance results obtained using regression methods. These data show that there was a strong association between the subjective pain scores (via app or nurse-obtained) and the predicted pain scores derived from wearable sensor signals.The result of the SVR model with the best performance can be visualized in To better analyze the results of these regression methods, the residual plots of 4 regression models using the backward elimination feature set are illustrated in In either To apply classification to the original dataset, pain scores ranging from 0 to 10 were categorized into 4 classes as mentioned above: none (0), mild (1-3), moderate (4-6), and severe (7-10). The number of samples for the 4 pain levels are 2, 4, 34, and 67, respectively and indicates a high-class imbalance among the 4 classes. As patients visit the hospital because of pain management issues, the skewing to higher level pain scores makes clinical sense.The SVM classifiers were applied on the categorized input dataset and evaluated for accuracy. F1 scores as well as a weighted F1 score were also evaluated. Accuracy is the ratio of correctly predicted pain scores over total number of pain scores. F1 score is the harmonic mean of precision and recall for each pain score, where precision is the ratio of the number of correctly identified entities with this pain score over the total number of this particular pain score predicted by the model. Recall is the ratio of the number of correctly identified entities with this pain score over the total number entities with this pain score in the dataset . The weiThe classification result of the SVM model was compared with that of the best performance model, which was the SVR model applied on the backward elimination feature set as described above. In the experiment, both SVM and SVR were implemented on the backward elimination feature set. For a fair comparison, the same kernel was used in SVM and SVR. In addition, the continuous predicted pain scores of the SVR model were categorized into 4 classes. In this way, the accuracy, F1 scores, and weighted F1 score were calculated for the SVR model. From This study demonstrates the feasibility of using physiologic data collected on a wearable device and applying these data using machine learning techniques to accurately predict subjective pain scores. The best accuracy was found using the machine learning technique SVR, with an accuracy of 0.729 prediction of pain on a 4-point scale. In addition, for patients treated in the day hospital for pain, we found expected improvement in pain and physiologic measures such as HR from the beginning to the end of their stay.Our predictive results are encouraging and provide insight into potential techniques to predict pain and the understanding of individual physiologic response to pain and treatment. A few investigators have recently begun to evaluate the potential use of physiologic data to develop digital phenotypes for pain and, subsequently, an individualized pain prediction model. As discussed previously, objective and physiologic data of varying invasiveness have been utilized in medicine to better understand disease processes and symptoms, including SCD. Coates et al have extensively published on objective data in SCD, including spin-tagged magnetic resonance imaging to assess cerebral oxygen extraction and metabolic rate, biventricular dimensions and function to assess cardiac iron load, and the use of a graphical Lasso model to evaluate functional brain connectivity in SCD -40. ThisA more objective pain prediction model could significantly help medical providers manage pain crises. As described, data collected from wearable devices can be utilized to improve pain management via advanced machine learning methods. In this analysis, we aimed to build predictive models for pain based on objective, physiologic wearable sensor data. This study is of great value given that the data utilized were obtained from a wearable device and provided minimal to no risk to patients. Furthermore, wearable sensor data were acquired frequently and obtained passively from patients as compared with nurse-documented vitals, which were obtained approximately every 2 hours.Importantly, wearables and mobile apps (to track symptoms and pain scores over time) paired together to form an mHealth pain prediction system, as in this study, could fairly easily be applied to the inpatient and outpatient settings. mHealth systems are attractive for providers as pain can be tracked on a more frequent basis and can provide more personalized care for patients and potentially prevent ED visits, day hospital visits, and hospital admissions. Further work is needed in this field to continue to develop models with increasing accuracy in predicting pain to help guide management and patient care .There are limitations to our study, including obtaining a convenience sample from our day hospital only and the small number of patients. Patients with SS and SC can be treated the same clinically, but the study included patients with thalassemia who may have a more or less severe phenotype depending on the type of thalassemia. Specific analysis on these patients was not performed for this feasibility study. The study is also limited given that patients might have had underlying medical conditions that could affect HR, and this was not controlled for in our study. In addition, each patient had pain control achieved through individualized pain protocols, which varied among patients and were administered at various intervals. Therefore, it was impossible to control for these pain medications during this initial study. Medications administered, both opioid and nonopioid, may affect vital sign parameters independently . The administration of pain medication, however, provides an important future opportunity to also evaluate pre- and postadministration objective datasets for pain prediction. Although all patients were in the day hospital either in a chair or bed, their environment was not completely controlled, and HR changes might have occurred with movement in and out of the bed or chair as well as to use the restroom, and these movements were not accounted for. HR can also vary outside of pain when a patient is at rest based on a multitude of different factors including stress, excitement, and breathing.In addition, our group had to make the assumption that nurse-documented pain scores and patient-reported pain scores in the app were not dissimilar, but this is also an area for further study. One hypothesis would be that the patients could report a lower pain score to the nurse to look tough, but an alternative hypothesis may be a patient elevating their pain score to be given additional medication. There is also the assumption that the physiologic measures from the wearable device are accurate. We attempted to take data averaged over 1 min  to minimize variability. We chose the Microsoft Band 2 because of the ability to acquire the raw data directly from the wearable and because of previous studies showing its relative accuracy. Stahl et al  and ShchUtilizing mobile devices and technology have great promise as we have discussed, but HR data and other physiologic parameters should be interpreted in the clinical context of the patient’s history and exam. For example, a tachycardic patient should be thoroughly evaluated to rule out life-threatening conditions before attributing tachycardia to pain. Although our group has shown that wearable sensor data are feasible to obtain and can be used to create models for predicting pain scores, models and objective vital signs need to be paired with clinical experience and judgment for ideal patient management.Future directions include refining the predictive model with a larger dataset. We are continuing to troubleshoot our data extraction procedure to minimize lost data. Furthermore, we could attempt to expand our models by examining patient’s disease severity , length of stay in the day hospital, etc, to obtain a more ideal model for pain score prediction. Given that we combined app pain scores with nursing pain scores, further study is needed to determine if these can be treated as similar scores. Related to medication administration, we could examine HR changes before and after medication, time since last dose, total net dose of medications, etc, and attempt to project pain score and the need for medication before the patient requests medication. This would be an essential part of a real-time pain forecasting system and allow a trial that evaluates the timing of administration of additional doses of opioids based on physiologic and objective data alone. Our initial results indicate promise in pursuing each of these efforts, and our study is a valuable addition to ongoing studies investigating how physiologic and objective data can be used to help providers better understand and treat pain.


No study on the effect of dual-cure stabilizer splint without canine ramp in migraine patients is present.This study was conducted to determine the effects of maxillary flat dual-cure stabilizer occlusal splint on severity, frequency and episodes of headaches in individuals suffering from a migraine.SPSS 20 and Kolmogorov-Smirnov test and paired t-test.In this interventional clinical trial, 30 eligible patients were divided into 2 groups (case and control); each group consisted of 8 men and 7 women. Dual-cure stabilizer splint was made for patients in the case group and they used the adjusted splint 20 hours a day for 6 weeks. The severity, frequency and episodes of migraine attacks before and after using the splint were determined. For grading pain, severity visual analogue scale was used. The data were analyzed using p < 0.05).The severity, frequency, and episodes of migraine attacks before and after using the splint were reduced by 56%, 68%, and 72%, respectively. The reduction was statistically significant (Despite the effect of occlusal devices on the migraine disorder is controversial, the most researchers agree that using these appliances can be effective in reducing headache in migraine patients.Given the favorable effects of dual-cure stabilizer splint on reducing the severity, frequency and episodes of migraine headaches, the device can be used as an effective alternative therapy besides common pain-relieving methods. Migraineurs experience severe pain and more than 90% of them report substantial disability during their headaches. From a clinical aspect, the most common comorbidities of migraine are anxiety disorders and depression. The 3 best features that have predictive value for migraine are nausea, disability, and photophobia. Actually, if the patient reports 2 of these 3 symptoms, they have an 81% probability of having migraine. For patients with 3 symptoms, this probability according to the International Headache Society (IHS) diagnostic criteria for migraine is 93% [The correlation between migraine headaches and pericranial muscle spasm has been clearly established , 4. The A migraine is treated using medical and non-medical methods. One of the non-medical methods is using occlusal splints. Using the stabilizer splint seems to have following changes: Situating the teeth in the centric relation, helping the facial muscles to be in the state of relaxation, equilibrium and stability in the centric relation and establishing a consistent contact between mandibular and maxillary teeth , 9.Furthermore, other researchers showed a decrease in the number and severity of headache attacks following a functional treatment combined with exercise therapy, splint, and correction of occlusion , 11.Moreover, the effects of the occlusal treatment in patients with various types of headache have been examined, and the patients showed a decrease in the number and severity of headache attacks , 13. Theversus the effects of occlusal splints. This appliance is made in the centric occlusion, and no other determinant such as the anterior guide is added to the occlusion. After 8 weeks of using NTI system, 16% of patients showed a decrease in the incidence of migraine headaches by 85-100%, and only 7% of patients using splints showed 85-100% decrease in the incidence of migraine headaches.Shankland compared the effect of using the pericranial suppression mechanism with that of occlusal splints on reducing the frequency and severity of migraine headaches . The stuMitrirattanakul and Merrill examined the effects of headaches on patients with oral and facial pain. They found that the concurrent primary headaches and musculoskeletal disorders might increase the headache disability in patients, and clinicians should treat both diseases simultaneously in order to achieve favorable results .et al. studied the relief of headache symptoms after using the stabilization appliance and self-medication methods in patients going to a clinic for chronic headaches. They concluded that the use of the appliance with self-medication without any association with the type of headache  was useful in many patients suffering headaches [Wright eadaches .et al. analyzed the results of treatment using Vojta/Dynamic Neuromuscular Stabilization device for 12 weeks in a 49-year-old woman with chronic migraine headaches. The study showed a decrease in frequency, duration, and severity of the headaches after using the stabilization device [Juehring n device . Numeroun device , 4. Acco2This randomized non blinded clinical trial was designed on patients, from March 2015 to October 2016, going to the neurology ward of teaching hospitals and then referred to the Department of Tempro Mandibular Joint (TMJ), School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran. This study has been registered as thesis no 4945 in dental school and an ethical board approved the design of the study.2.1The sample size was calculated by the following formula and information from similar paper .1: Standard deviation of pain severity in control group= 0.5∂2: Standard deviation of pain severity in case group= 0.22∂1: Mean of pain severity in control group= 2.02µ2: Mean of pain severity in case group= 1.28µα<0.1β < 0.05The sample size was 15 in each group (case and control). Patients were selected by purposive sampling and divided into two groups by method of random blocks.2.21. The inclusion criteria were: patient’s age between 20-55 years, good oral hygiene without periodontal problem, headache confirmed as migraine disorder by a neurologist, no history of treatments associated to the occlusion (including the splint therapy), having all the teeth or maximum one extracted tooth (except wisdom teeth), having maximum one bridge or three laminated teeth, having received at least two standard treatment for episodic migraine HA (acetaminophen (325 mg), diazepam (2 mg), and tripheloprazine (1 mg), sublingual ergotamine, dihydroergotamine injection, or ergotamine-C tablets).The inclusion and exclusion criteria are shown in Table e.g., fibromyalgia), a source of pain other than migraine in their head and neck , a history of diseases or conditions overlapping with migraine headache , signs of untreated periodontal disease or other mucosal and bone lesions, gingival recession or periodontal pockets .The patients were excluded if they had any history of using opiate, medication or drug that could jeopardize the treatment outcome, systemic diseases increasing or decreasing the pain threshold  were included in this study and signed an informed consent form after being informed about the treatment protocol. The treatment period for patients was determined 6 weeks.2.31). Each patient received daily checklists for 6 weeks. The patients were asked to record the starting and ending time of the pain and severity of the pain.Each patient filled a questionnaire on the history of headache attacks. The main questions included the following: how many years do you have migraine disorder? how much is the headache severity according to VAS? how many headaches do you have in one month? how long does each headache last?. The pain severity was scored according to the Visual Analogue Scale (VAS) from 0 (no pain) to 10 (worst possible pain)  2.4The patients in the control group were left on their same baseline medications and the patients in the case group received the dual-cure stabilizer occlusal splint without canine ramp on the maxilla. For making a splint for each patient, impressions were made using irreversible hydrocolloid  and patients’ bite in centric relation  was recorded with base plate wax .In the delivery session, appliances were adjusted to have equal contact on the anterior and posterior teeth in centric relation. Also, patients were educated to use the appliance all the day except for eating and cleaning.2.5The patients in the case group were recalled two weeks later . They were re-evaluated in terms of retention and stability, the shape of the splint, and occlusal contacts because the presence of these items led to patients’ comfort and treatment continuity and stability.SPSS 20  and Kolmogorov-Smirnov test and paired t-test. Level of significance was 0.05.The next meeting was held at the end of the sixth week  to make final adjustments, submit checklists, and complete the questionnaire again. The All patients (the control and the case group) were asked to bring their daily checklist and complete the questionnaire again. Moreover, the case group was instructed how to reduce the time of using splint, as the time of using splint was reduced by 8 hours at the beginning of the seventh week and since then reduced daily by one hour, as the splint should be used only at nights in the eighth week . All spl3The severity, frequency and episodes of migraine attacks before and 6 weeks after using the splint were determined.Most patients were 20-30 years old. Given the confidence interval of 95%, mean pain severity in patients using the splint was lower (3.5-5) than that in the control group -6. Mean P-value ≥ 0.05) . The measurements in the control group before and after the treatment were similar. There was a significant difference between results of case group before and after the treatment in terms of all the variables (p < 0.05). Patients using the splint  showed a tangible reduction in all the variables after the treatment. The results of study have been summarized in Tables 2, 3 and 4. Demographic information of case group has summarized in Table 5.Based on the results of Kolmogorov-Smirnov test, all the studied variables followed a normal distribution in the statistical population (4In the present study, the effect of dual-cure stabilizer splint without canine ramp on reducing the pain of migraine headaches was studied.According to the results of this study, the dual-cure stabilizer splint could considerably reduce pain severity, frequency, and duration of pain episode in patients with migraine headaches. The severity, frequency, and duration of pain episode of migraine attacks before and after using the splint were reduced by 55.8%, 67.7%, and 72.1%, respectively.Despite the different ideas of researchers and dentists about the use of splints for treating migraine headaches, the dominant opinion is that the use of different types of the splint can be effective in reduction of migraine headaches , 24.The previous studies showed that despite the diversity and differences in the designs of different splints, these appliances enjoyed special medical efficiency . HoweverAfter adjusting the splint with the mouth, the associated muscles would rest, teeth would be protected against adverse effects of parafunction, and periodontal ligament movements in teeth would become normal. Moreover, these splints can conduct condyles and jaws to the centric relation .It seems that the presence of a foreign body in the mouth may reduce jaws’ nocturnal activity due to the changes made in oral tactile stimuli, size of mouth, and the space needed for the tongue . Using tCarraro and Caffesse studied TMJ patients’ responses to the stabilization splint and showed that 82% of them responded to the treatment with splints favorably and their symptoms of TMJ and muscular pain and headaches were treated . Resultset al. studied the therapeutic effects of oral splints using a randomized controlled blind parallel design and showed that patients’ scores for pain were significantly reduced following the use of splints [Dao  splints . Shankla splints . Jokstad splints .et al. treated patients with a migraine, tension, and tension-vascular headache using splints and showed that a considerable number of patients were satisfied with the treatment after 3 months although a tension headache in most of the patients did not decrease significantly [Furthermore, Lamey and Barclay treated patients with a classic migraine using acrylic splints and reported a significant reduction in number and severity of migraine attacks . Anotherficantly . Lamey sficantly . In the Although a different design of splints was used in the present study to reduce patients’ migraine headaches, the obtained results on the reduced severity, frequency, and duration of pain episode conformed to and was even more favorable than, those of the previous studies.The limitation of this study was that there was no group with a standard occlusal splint to compare with dual-cure stabilizer splint without canine ramp group. Also to achieve more conclusive and definitive results, it is better to design a study with more patient and more follow up time.It is recommended that future clinical studies be conducted to compare occlusal splints with different designs.Under limitation of this study, the following conclusions were obtained:Dual-cure stabilizer splint without canine ramp reduced the severity, frequency, and episodes of migraine attacks before and after using the splint.The severity of headaches decreased by more than fifty percent.The frequency of headache was more than 4 times a month and now after treatment is less than twice a month.The duration of each headache decreased by more than 10 hours.


Spinal anesthesia is the common choice for anesthesia in lower abdomen surgery and intrathecal adjutants have gained popularity with the aim of prolonging the duration of block, quality of block and post operation pain control. The purpose of this study was to evaluate the effects of adding dexmedetomidine to hyperbaric bupivacaine in lower abdominal surgery under spinal anesthesia. The main outcomes were considered pain score, duration of analgesia, hemodynamic changes and adverse side effects like nausea and vomiting.This double-blind randomized clinical trial was conducted on one hundred patients between 18 to 65 years old scheduled for lower abdominal surgery. Fifty patients were randomly allocated to receive either 12.5mg hyperbaric bupivacaine (2.5cc) plus 5µgr dexmedetomidine (0.5cc) intrathecally while fifty patients received either 12.5mg hyperbaric bupivacaine (2.5cc) and 0.5cc Saline 0.9% intrathecally.Vital sign parameters like heart rate, blood pressure and oxygen saturation levels were registered in the normal range in both groups. The average duration of the onset of pain (230±86 min) in bupivacaine group was significantly (p≤0.000) less than dexmedetomidine group (495±138 minutes). The severity of pain at all times in dexmedetomidine group was significantly (p<0.05) less than bupivacaine group. The severity of shivering and the number of patients who needed treatment for nausea and vomiting in dexmedetomedine group has been less in comparison to bupivacaine.We concluded that intrathecal dexmedetomidine increases the duration of analgesia and reduces postoperative pain without changes in the hemodynamic parameters and adverse side effects. It can be considered as an appropriate adjuvant to intrathecal local anesthetics for lower limb surgeries. Postoperative pain is a major concern for patients and postoperative pain management is considered as a part of perioperative care . Lower aAlpha receptor agonists are added to local anesthetics as an adjuvant to improve their effects and reduce the required dose of anesthetics . DexmedeIn this double-blind randomized controlled trial study in 2013, 100 patients aged between 18 and 65 years, in ASA (American Society of Anesthesiologists) class I, II and candidate for elective lower abdominal surgery, such as prostatectomy, varicocelectomy, hysterectomy, and inguinal herniorrhaphy, were included after obtaining their informed consent in Shahid Beheshti Hospital in Babol. This study was registered in the Clinical Trial Registration Center of Iran under the code IRCT201310293305N6. Patients with a history of cardiovascular diseases, dyspnea, diabetes, and renal or liver complications, patients with a history of taking narcotics, antiepileptic drugs, antipsychotics, and/or analgesics, and patients with a history of consuming alcohol were excluded. In addition, patients with severe pain at the operation site during surgery, which necessitated general anesthesia, were removed from the study. Sample size calculation was performed on Hong study’s result  and its Then, Ringer's serum (5 ml per kilogram body weight) was administered through intravenous cannulation. After measuring HR, BP, and SPO2 (as basic measurements), patients were placed in a sitting position, and prepping and draping were conducted. Then, the case group received intrathecal injection of 2.5 ml of bupivacaine (0.5%) and 0.5 ml of dexmedetomidine (5μg); whereas, the control group received intrathecal injection of 2.5ml of bupivacaine (0.5%) and 0.5 ml of normal saline at lumbar segments 3-4 (L3-L4) or 4-5 (L4-L5), using 25-gauge needles (B-Braun Co.). After placing the patients in a supine position, all of them received a venturi mask with an oxygen flow between 5-6 ml per minute. In addition, 1/1-2 mg of intravenous midazolam, as a sedative, was administered. Both the patient and outcome assessor were blind to the type of administering intrathecal drug. Hemodynamic parameters of the patient in the 0 (baseline), 5th, 10th, 15th, 30th, 60th, and 120th minutes and 6th, 12th, 18th, and 24th hours were measured and recorded. Patients with systolic blood pressure < 90 received 5-10 mg of ephedrine. Moreover, patients with HR < 60 per minute received 0.5 mg of atropine. During surgery and recovery, the patients were examined and were categorized in terms of shivering, which was graded as follows: 0 = no shivering, 1= piloerection or peripheral vasoconstriction, but no visible shivering, 2= shivering in only one muscle group, 3= shivering in more than one muscle group but not generalized, and 4 = generalized shivering involving the whole body. Patients with extreme and generalized shivering (grade 4) were treated with pethidine 25 mg. In addition, patients were graded between 0-10 over 24 hours after the surgery in terms of postoperative onset and severity of pain was based on a visual analog scale (VAS). The VAS pain grading system is as follows: 0 = without pain, 1-2 = slight pain, 3-4 = mild pain, 5-6 = moderate pain, 7-8 = severe pain and 9-10 = the worst pain. If pain grade of a patient was greater than 4 and/or the patient ask for analgesics because of having pain, pethidine 0.5 mg per kilogram body weight (maximum dose=30 mg) was administered. Additionally, patients were investigated in terms of nausea and vomiting over 24 hours after the surgery. Intravenous metoclopramide 10 mg was administered to patients with such problems. In this study, severity of pain at different times and average duration of the onset of pain as primary outcomes and shivering, nausea, and vomiting post operation as secondary outcomes were recorded. Patients lost to follow-up were excluded from the study completely. Data were analyzed using chi-square test, Fisher’s exact test, t-test, Mann-Whitney U test, and repeated measures in SPSS 16. Furthermore, p<0.05 was considered to be significant. This study was conducted on 100 patients, who were equally divided into dexmedetomidine plus bupivacaine and bupivacaine groups. There were 40 (80%) women and 10 (20%) men in the bupivacaine group and 22 (44%) women and 28 (56%) men in the dexmedetomidine group . The mean and standard deviation of other demographic characteristics of the patients in both groups are presented in The mean and median of severity of pain at different times for both groups is presented in  The mean pethidine intake in the bupivacaine group and dexmedetomidine+bupivacaine group was 87.5 mg and 33.6 mg, respectively (P=0.000). The shivering, nausea, and vomiting conditions of the patients in both groups are presented in The use of dexmedetomidine as a local anesthetic adjuvant has been increasingly reported to extend the duration of both motor and sensory blockade produced by single Injection neuraxial. , 3. The Based on VAS, the severity of pain in all investigated periods after the onset of pain was significantly lower in the dexmedetomidine plus bupivacaine group than in the bupivacaine group. In a study conducted by Kaya FN et al. in Turkey on 75 ASA I and II patients undergoing spinal anesthesia with bupivacaine, patients were randomly divided into three groups. The first, second, and third groups received intravenous dexmedetomidine, midazolam, and intravenous normal saline before spinal anesthesia, respectively. The results showed that the intravenous administration of dexmedetomidine could increase the duration of bupivacaine block, sedation, and analgesia . In a stThe results showed that despite significant differences between the two groups in examining hemodynamic parameters, such as HR, BP, and OS, in some points of time, they followed a normal decreasing trend. Moreover, the hemodynamic decreasing trend (HR and BP) during the examined period was greater in the dexmedetomidine group than in the dexmedetomidine+bupivacaine group, but not significantly. This difference may be due to the inherent effect of dexmedetomidine . Kanazi Also, the dexmedetomidine+bupivacaine and bupivacaine groups were not significantly different in terms of shivering; however, it was more severe in the bupivacaine group, so the eight subjects in this group (versus no subject in the dexmedetomidine plus bupivacaine group) needed treatment. Burhanettin Usta et al. in 2011 designed a study in Turkey on 60 ASA I and II patients, aged 18-50 years, undergoing elective minor surgeries under spinal anesthesia. The patients were randomly divided into two groups. The first and the second groups received intravenous dexmedetomidine and intravenous normal saline, respectively. It was observed that dexmedetomidine could significantly reduce shivering in spinal anesthesia without causing any significant complication .The postoperative nausea and vomiting conditions in the two groups were not significantly different; although, fewer patients in the dexmedetomidine group needed metoclopramide treatment. Massad et al. conducted a study on 81 ASA I patients undergoing laparoscopy. Their results showed that adding dexmedetomidine significantly reduced the incidence of postoperative nausea and vomiting .In Conclusion, Administration of dexmedetomedine through the intrathecal route by acting as an adjuvant drug to local anesthetics provided an analgesic effect in postoperative pain without sedation. It could potentiate the effect of the local anesthetic and allow a decrease in the required doses. The present study showed that dexmedetomidine in addition to local anesthetics could prolong the duration of both sensory and motor blockade and postoperative pain management without causing a significant clinical change in patients’ hemodynamic conditions.Limitations of this study:Trying to gather the exact data in close monitoring during surgery and unreliable patient's information were the major limitations of this study, while this trial like other trials could be influenced by experimenter bias, straw man comparison, unsuccessful randomization and composite outcomes as potential limitations of all clinical trial.


Due to the recurrent nature of low back pain (LBP), the traditional concepts of cure and recovery are challenged, and investigating the course rather than status at fixed time-points may help us understand prognosis as well as treatment effect. However, methods of frequent measuring still need development and validation. Therefore, this study aims to evaluate the agreement between continuous, quantitative self-assessment (weekly SMS) of the course of LBP over a one-year period and qualitatively derived retrospective patient self-appraisal of the same time-period.Participants were 32 subjects with LBP from primary care. The quantitative measures consisted of weekly SMS questions for one-year about pain intensity, days with LBP, and activity limitations for that week. For each subject, the weekly responses were graphed and categorized into categories based on intensity, variation and overall change patterns. Qualitative measures were based on semi-structured telephone interviews one-year after a consultation for LBP, where two coders independently categorized the self-appraisal of LBP course into the same predefined categories as the SMS-based trajectories. Furthermore, patients’ perceived overall recovery was related to variation patterns from SMS track.There was perfect agreement for 48% in the pain intensity domain, 53% in the variation domain and 63% in the change pattern domain. Most of the discordant cases were classified in neighboring categories with the majority relating to fluctuating patterns. The self-perceived overall recovery status seemed to be reflected quite well by the quantitative measures of pain intensity and days with pain in this study.This study shows that a real time quantitative measure (weekly SMS) and the patient’s retrospective appraisal do not fundamentally differ in their reflection of the one-year course of LBP.As a first investigation into this area, these results are promising, as longitudinal quantitatively derived trajectories of LBP seem to reflect the lived experience of the patient to a large degree. Furthermore, the patient’s ability to retrospectively recall their one-year course of LBP appears to be quite good. Future studies should focus on refining the categories of trajectories.The online version of this article (10.1186/s12998-018-0222-y) contains supplementary material, which is available to authorized users. The assessment of patients’ outcomes is essential in all areas of health care as well as in clinical research. However, in diseases that are not life threatening it is not straight forward defining what a “successful” outcome is. In back pain, this is clearly demonstrated in two reviews of recovery definitions , 2. In tQualitative studies have demonstrated that patients’ sense of recovery from LBP is both complex and highly individualized , but nevIn attempts to more accurately reflect the course of LBP rather than using a single time-point measure, trajectories of LBP based on frequently repeated measures have been created –18. ThesThe primary objective of this study was to compare SMS-based trajectories as defined by Kongsted et al.  to interA probing convergent mixed method study comparing quantitatively and qualitatively derived outcome measures in a primary care setting .. The study included LBP patients from general physician practices and chiropractic practices to reflect LBP-patients in Danish primary healthcare.Participants were recruited from a prospective cohort study with one-year follow-upChiropractors from 17 out of 21 invited chiropractic clinics from the research network of the Nordic Institute for Chiropractic and Clinical Biomechanics agreed to recruit consecutive patients with LBP from September 2010 to January 2012. Prior to inclusion, patients received written and verbal information about the study. During the 16 months, 947 patients were included.All 800 GPs in the Region of Southern Denmark were invited to participate in a quality development initiative by the Audit Project Odense . The objThe inclusion criteria for both chiropractic and general practice populations were LBP with or without radiating pain, 18–65 years of age, and access to a mobile phone. Exclusion criteria were pregnancy, suspicion of serious pathology and inability to read and write Danish. Furthermore, an additional exclusion criterion for chiropractic practice was having had more than one health care visit for LBP within the last 3 months.For this study, we drew our sample from the participants who had completed the one-year follow-up in the cohort study and no longer received the SMS questions. To ensure a broad and inclusive set of responses we employed a purposive maximum variation sampling framework: The first 12 participants were consecutively included at least a week after they completed their 1-year follow-up, and were thus eligible for inclusion. Three attempts were made to contact a particular individual (on different weekdays). If the individual could not be contacted, they were excluded and the next person on the list was contacted for potential inclusion. These 12 participants were supplemented by a maximum variation sample of 20 respondents. These were identified by distinctly different SMS-based trajectories and ensured a variation in the course patterns and has been described in detail previously . PatientAll members of the cohort study were sent weekly SMS questions for 1 year. The cohort members first responded to the following question “How many days did you have low back pain during the last week? (A number between 0 and 7)”. If they responded with at least 1 day of LBP, they were subsequently asked the following questions: “How intense was the pain typically on a scale from 0 to 10?” ) and “How many days during the past week has your low back pain limited your activities? (A number between 0 and 7)”. If zero LBP days were reported, the NRS and activity limitation were assumed to be negligible and thus coded as zero. If cohort members did not respond to the SMS-questions for two consecutive weeks, a research assistant telephoned them to remind them about the study.We conducted semi-structured, telephonic interviews. Telephonic, rather than face-to-face interviews were chosen due to a wide geographic spread of respondents in the cohort study. The interview guide consisted of three core questions: “Are your back problems over?”, “To what extent have your back problems affected you?” and “Has anything special occurred during the last 12 months in relation to your low back problems?” Thus, interviewers avoided drawing attention to specific domains related to the problems, i.e. pain intensity. Participants were encouraged to explain and elaborate their answers.‘excluding the initial episode’ to the criteria for the ‘single episode’-category. Furthermore, a category describing the change pattern as ‘unchanged’ was added and the four categories in the intensity domain were combined into two categories (‘none to mild’= NRS 0–3 and ‘moderate to severe’: NRS 4–10), because we considered that to be a more realistic level of distinction obtained from interviews. The categories and their operational criteria are shown in Fig. SMS trajectories were illustrated in time-series line plots for the 32 interviewed subjects. Two examples are shown in Fig. Are your back problems over?” were coded as ‘yes’, ‘no’ or ‘unsure’. Two of the authors (EB and CM) independently coded each interview and met to discuss the disagreements.Interviews data were recorded, transcribed verbatim and translated into English, since both assessors were native English speakers (EB and CM). Using the operational criteria, a codebook was derived by CM. Codes were applied for each of the categories within the three domains shown in Fig. First, the interview-based trajectories and the SMS-based trajectory categorizations were cross-tabulated separately for the three domains and the percent agreement was determined. Next, cases with disagreement were described with respect to the SMS-track. For this description, SMS questions about activity were also considered as potential explanations since the SMS categorizations were only based on questions about pain intensity and frequency.Weighted Kappa statistics were intended but due to several empty cells in the tables, this was not feasible.Are your back problems over?” with the SMS-based trajectories from the ‘variation’ domain.For the secondary objective, to compare the SMS-based trajectories to peoples’ overall assessment of their perceived recovery based on interviews, we compared and contrasted the response to the interview question “It was noted that more patients were categorized as ‘moderate to severe’ with respect to pain intensity in the interviews than in the SMS-based trajectories, and that many of these disagreements related to patients who had been pain free for part of the time. Therefore, categorization based on SMS-track was repeated with the mean pain score based only on the intensity of pain during pain episodes, i.e. pain free episodes ignored.The flow of the study is illustrated in Fig. SMS trajectories from two subjects were excluded due to too few SMS-answers  leaving 30 subjects for the comparative analysis. The group consisted of 19 women and 11 men with a mean age of 45.9 (SD 10.5) years and a mean baseline pain intensity of 6.8 (SD 2.0).The two assessors agreed in 97, 93 and 77% of the cases in the intensity, variation and change domains, respectively. In case of disagreement, consensus was reached through discussion and all patients were classified in all three domains.In the pain intensity domain, most (74%) were classified as ‘mild’ (0–3); in the variation domain, the most common category was ‘episodic’ (40%) and in the change pattern domain, ‘slow improvement’ was the most common (46%). Two examples of trajectories can be seen in Fig. Due to the explorative nature of the interviews, all patients could not necessarily be classified in all domains. In the variation domain all were classified, but seven patients could not be categorized in the pain intensity domain and six in the change pattern domain, because the relevant issues were not referred to during the interviews.In the pain intensity domain, ‘moderate to severe’ was slightly more prevalent than ‘mild’ (52% vs. 48%); in the variation domain, the most common category was ‘episodic’ (37%) and in the change pattern domain, ‘rapid improvement’ was the most common (42%). All individual categorizations can be seen in Additional I got up and it got so extreme and then I couldn’t even walk anymore, …” (ID 19)Intensity, intense: “I feel a little pain in my back once in a while, but that doesn’t bother me much. ”(ID 14)Intensity, mild: ““…, related to the scale we have been using at times, 1 – 10, it is about 3 – 5 approximately, it goes up and down.” (ID 14)Variation, fluctuating: : “I feel back pain every day more or less.” (ID 8)Variation, ongoingI feel pain once in a while. And then, then I go see the chiropractor and do some exercises myself,…” (ID 3)Variation, episodic: ““..what do I get, around three or four treatments, and then it is simply gone and there hasn’t been anything since – at all” (ID 12)Variation, single episode: It has been sort of stable, lately I think it is getting worse” (ID 23)Change pattern, progressing: ““It has actually been stable. Well, but those pains are always there and.. what can you say… some days are worse than others, but I have back pain constantly” (ID 24)Change pattern, ongoing: “… I can feel it a little once in a while and so, but not as violently as it was in the beginning …” (ID 29)Change pattern, gradual improvement: “It came suddenly and it disappeared suddenly.” (ID 9)Change pattern, rapid improvement: Typical quotes for each category within the three domains were:All categories for the individual patients are shown in Additional file Cross-tabulations between the categorizations based on interviews and the categorization based on SMS questions within the three domains: pain intensity, overall change patterns, and variation (frequency), respectively, are shown in Tables The percentage of agreement for pain intensity was 48% and the major discrepancy (9 of the 12 discordant categorizations) was due to pain being rated higher in the interviews than from the SMS-track , the corresponding figures were four and zero.There were two patients rated as ‘unchanged’ on SMS-categorization and ‘progressing’ on interview-categorization. One of these was very constant in SMS reporting with pain intensities of 8 or 9 with only 1 week’s exception (ID: 21); the other had a very large variation across the whole year (ID: 23). Two patients were categorized as unchanged from interviews but showed a slowly improving pattern on the SMS-track. For one of these, the improvement was within the first 16 weeks, where after the SMS reports was constant for the rest of the year (ID: 14), and the other had an unchanged pattern of fluctuations for the first two thirds of the year, whereas the last third of the year had been good with pain reported only 1 week (ID: 18).None of these disagreements could be explained by activity limitation, since this was either very low or followed the pattern of pain intensity, but the main discrepancies were within the first half of the year.n = 7) or ‘episodic’ (n = 8) in the variation-domain based on the SMS-trajectories.When asked directly, 15 responders thought they were over their back problems, nine did not and six were unsure. The 15 responders who answered “Yes” to being over their back problems were all categorized as either ‘single episode’ (not consider themselves to be over their back problems were mainly ‘fluctuating’ (n = 5) or ‘ongoing’ (n = 3), but one was classified as ‘episodic’ (ID = 8). However, this patient only had one pain free episode during the year and had rather high reports of pain the last 14 weeks, so based on the SMS-track that would not be considered as recovered either.The group who did The trajectories from the six unsure patients showed that some of this uncertainty was explainable by recent recurrences or improvements without complete remissions. However, the uncertainty in two of the six seemed to be unrelated to the SMS-based trajectories.This study explored whether researchers’ interpretation of frequent quantitative outcome measures (SMS track) was coherent with how patients describe their course and recovery and was a first attempt to compare quantitative and qualitative measures of a one-year course of LBP. Generally, the interviews supported the findings from the quantitative measures, but fluctuations were not a clear part of peoples recall and therefore difficult to define from interviews.As expected, patients did not consider themselves as being recovered from their LBP when they were quantitatively defined as ‘fluctuating’ or ‘ongoing’. However, episodic pain appeared to have less impact, since eight individuals considered themselves recovered, despite being categorized as ‘episodic’ by SMS. This demonstrates that LBP is fluctuating in nature, and people with LBP patterns categorised as fluctuating had more severe and disabling LBP than those with episodic pain. Thus, it appears that it makes an important positive difference to people with LBP to have periods that are pain free. This is in line with previous observations .We encountered no difficulties with assigning the SMS-based trajectories to the predefined categories, and all patients could be assigned to the variation category based on interviews, but there were difficulties with the domains of pain intensity and change pattern. One explanation could be a mismatch between the patients’ and researchers’ understanding of the concept of pain intensity. Regarding change patterns, the interviews should probably have explored the timeframe in more detail. Further research is needed to elaborate on this.Although a substantial body of literature suggests that quantitative measures only reflect part of the patients’ experiences –27, the Overall, we did not detect a bias toward more or less pain intensity in the reporting from interviews compared with weekly SMS’s. This could however be due to inherent prompting in the design: when a patient recalls the pain, it is likely a reflection of the pain when it was present, whereas, the SMS-based categorization was a mean calculated across the whole year, including pain free episodes. However, the post-hoc analysis, ignoring pain free periods, did not improve the agreement substantially. Another theory is that the patients’ recollection of pain level is influenced by present pain level as has been reported previously  but suchWith regard to variation in pain across the year, there was quite a lot of disagreement, indicating some weakness in the operational criteria for the distinction between categories within this domain. However, with the exception of three patients, all were categorized in the same or a neighboring category. Especially the definition of ‘episodic’ based on only one pain free episode during the course of a whole year might be questionable.It appeared to be difficult to distinguish between slow and rapid improvement (more or less than 4 weeks), but if the rate of improvement is ignored, the change pattern domain had the best agreement of the three domains. The fact that the main discrepancies were within the first half of the year indicate that the first part of the year is either not recalled after 1 year  or is nocourse rather than the state of pain and disability, and therefore might improve outcome measurements in future research. Such an approach has been tested by Dunn et al. using almost similar trajectory illustrations as in the present study, and they demonstrated acceptable face, criterion and construct validity [We believe, the combination of interviews with open-ended questions and the strictly quantitative data from the SMS-track provides important insight into the quality of both. However, the limited number of interviews limits the use of statistics, such as estimation of Kappa values for agreement. Furthermore, the fact that the patients have received weekly SMS-questions about pain and activity limitation is an inherent weakness in the design. First of all, the weekly focus on two LBP-related concepts (pain intensity and activity limitation) might have given these concepts a disproportionately large weight in the patients’ appraisal of their course at a subconscious level. Furthermore, the patients’ ability to recall their course of pain might have been attenuated by the constant answering of SMS-questions, requiring appraisal of the pain status every week which might explain why our results did not seem to be as hampered by recall bias as often reported in the literature . Neverthvalidity . HoweverThis study shows that a real time quantitative measure (weekly SMS) and the patient’s retrospective appraisal do not fundamentally differ in their reflection of the one-year course of LBP.As a first investigation into this area, these results are promising with regard to patient’s ability to retrospectively recall their one-year course of LBP and likewise, longitudinal quantitatively derived trajectories of LBP seem to reflect the lived experience of the patient to a large degree. Future research should focus on the optimal timeframe for recall, better description of distinct categories and the relative importance of the three domains.Additional file 1:Individual categorizations by SMS-track and interview. Shows the categorization of each patient (random id-numbers) from both SMS-track and interviews. (DOCX 19 kb)