Longitudinal data analysis (repeated measures) in clinical trials

Body image and pelvic floor dysfunction in pregnancy and postpartum: A prospective one-year follow-up cohort study

OBJECTIVE

To determine the prevalence of pelvic floor dysfunction (PFD) among pregnant women, their clustering and their association with body image disturbance (BID) up to 1 year postpartum.

DESIGN

Monocentric prospective cohort study.

SETTING

University Hospitals Leuven.

POPULATION

Pregnant women attending for pregnancy care, first assessed prior to 14 weeks of gestation and agreeing to follow-up until 1 year postpartum.

METHODS

Standardised questionnaires reporting on PFD and BID at 12-14 and 28-32 weeks of gestation, and again at 6-8 weeks and 1 year postpartum. We calculated the prevalence of PFD, how the cases clustered and how the cases correlated with BID using a linear mixed-model analysis. A minimum of 174 women with complete follow-up were required.

MAIN OUTCOME MEASURES

The questionnaires used were the International Consultation on Incontinence Questionnaire - Urinary Incontinence Short Form (ICIQ-UI SF), St. Mark's Incontinence Score (SMIS), Patient Assessment of Constipation Symptoms (PAC-SYM), Pelvic Organ Prolapse Distress Inventory (POPDI), Pelvic Organ Prolapse/Incontinence Sexual Questionnaire IUGA Revised (PISQ-IR) and the Body Image Disturbance Questionnaire (BIDQ).

RESULTS

Out of 208 women, 92.8% reported one or multiple symptoms of PFD at 28-32 weeks of gestation, dropping to 73.6% by 1 year postpartum. The most common symptoms were constipation (65.3% at 28-32 weeks of gestation and 42.8% at 1 year postpartum) and urinary incontinence (56.8% at 28-32 weeks of gestation and 35.1% at 1 year postpartum). After correcting for body mass index, parity and mode of delivery, the severity of BID was associated with the ICIQ-UI SF score (β = 0.016, range 0.007-0.024), the PAC-SYM score (β = 0.006, range 0.002-0.011) and the POPDI score (β = 0.009, range 0.005-0.012), but not with the SMIS score (β = 0.015, range -0.001 to 0.031) or the PISQ-IR score, in sexually active women.

CONCLUSIONS

Urinary incontinence, constipation and symptoms of prolapse have a measurable impact on BID.

Bayesian transition models for ordinal longitudinal outcomes

Ordinal longitudinal outcomes are becoming common in clinical research, particularly in the context of COVID-19 clinical trials. These outcomes are information-rich and can increase the statistical efficiency of a study when analyzed in a principled manner. We present Bayesian ordinal transition models as a flexible modeling framework to analyze ordinal longitudinal outcomes. We develop the theory from first principles and provide an application using data from the Adaptive COVID-19 Treatment Trial (ACTT-1) with code examples in R. We advocate that researchers use ordinal transition models to analyze ordinal longitudinal outcomes when appropriate alongside standard methods such as time-to-event modeling.

Noisecut: a python package for noise-tolerant classification of binary data using prior knowledge integration and max-cut solutions

BACKGROUND

Classification of binary data arises naturally in many clinical applications, such as patient risk stratification through ICD codes. One of the key practical challenges in data classification using machine learning is to avoid overfitting. Overfitting in supervised learning primarily occurs when a model learns random variations from noisy labels in training data rather than the underlying patterns. While traditional methods such as regularization and early stopping have demonstrated effectiveness in interpolation tasks, addressing overfitting in the classification of binary data, in which predictions always amount to extrapolation, demands extrapolation-enhanced strategies. One such approach is hybrid mechanistic/data-driven modeling, which integrates prior knowledge on input features into the learning process, enhancing the model's ability to extrapolate.

RESULTS

We present NoiseCut, a Python package for noise-tolerant classification of binary data by employing a hybrid modeling approach that leverages solutions of defined max-cut problems. In a comparative analysis conducted on synthetically generated binary datasets, NoiseCut exhibits better overfitting prevention compared to the early stopping technique employed by different supervised machine learning algorithms. The noise tolerance of NoiseCut stems from a dropout strategy that leverages prior knowledge of input features and is further enhanced by the integration of max-cut problems into the learning process.

CONCLUSIONS

NoiseCut is a Python package for the implementation of hybrid modeling for the classification of binary data. It facilitates the integration of mechanistic knowledge on the input features into learning from data in a structured manner and proves to be a valuable classification tool when the available training data is noisy and/or limited in size. This advantage is especially prominent in medical and biomedical applications where data scarcity and noise are common challenges. The codebase, illustrations, and documentation for NoiseCut are accessible for download at https://pypi.org/project/noisecut/ . The implementation detailed in this paper corresponds to the version 0.2.1 release of the software.

Handling of outcome missing data dependent on measured or unmeasured background factors in micro-randomized trial: Simulation and application study

Background

Micro-randomized trials (MRTs) enhance the effects of mHealth by determining the optimal components, timings, and frequency of interventions. Appropriate handling of missing values is crucial in clinical research; however, it remains insufficiently explored in the context of MRTs. Our study aimed to investigate appropriate methods for missing data in simple MRTs with uniform intervention randomization and no time-dependent covariates. We focused on outcome missing data depending on the participants' background factors.

Methods

We evaluated the performance of the available data analysis (AD) and the multiple imputation in generalized estimating equations (GEE) and random effects model (RE) through simulations. The scenarios were examined based on the presence of unmeasured background factors and the presence of interaction effects. We conducted the regression and propensity score methods as multiple imputation. These missing data handling methods were also applied to actual MRT data.

Results

Without the interaction effect, AD was biased for GEE, but there was almost no bias for RE. With the interaction effect, estimates were biased for both. For multiple imputation, regression methods estimated without bias when the imputation models were correct, but bias occurred when the models were incorrect. However, this bias was reduced by including the random effects in the imputation model. In the propensity score method, bias occurred even when the missing probability model was correct.

Conclusions

Without the interaction effect, AD of RE was preferable. When employing GEE or anticipating interactions, we recommend the multiple imputation, especially with regression methods, including individual-level random effects.

Symptom tracking in endometriosis using digital technologies: Knowns, unknowns, and future prospects

Endometriosis is a common chronic pain condition with no known cure and limited treatment options. Digital technologies, ranging from smartphone apps to wearable sensors, have shown potential toward facilitating chronic pain assessment and management; however, to date, many of these tools have not been specifically deployed or evaluated in patients with endometriosis-associated pain. Informed by previous studies in related chronic pain conditions, we discuss how digital technologies may be used in endometriosis to facilitate objective, continuous, and holistic symptom tracking. We postulate that these pervasive and increasingly affordable technologies present promising opportunities toward developing decision-support tools assisting healthcare professionals and empowering patients with endometriosis to make better-informed choices about symptom management.

Solutions for surrogacy validation with longitudinal outcomes for a gene therapy

Valid surrogate endpoints S can be used as a substitute for a true outcome of interest T to measure treatment efficacy in a clinical trial. We propose a causal inference approach to validate a surrogate by incorporating longitudinal measurements of the true outcomes using a mixed modeling approach, and we define models and quantities for validation that may vary across the study period using principal surrogacy criteria. We consider a surrogate-dependent treatment efficacy curve that allows us to validate the surrogate at different time points. We extend these methods to accommodate a delayed-start treatment design where all patients eventually receive the treatment. Not all parameters are identified in the general setting. We apply a Bayesian approach for estimation and inference, utilizing more informative prior distributions for selected parameters. We consider the sensitivity of these prior assumptions as well as assumptions of independence among certain counterfactual quantities conditional on pretreatment covariates to improve identifiability. We examine the frequentist properties (bias of point and variance estimates, credible interval coverage) of a Bayesian imputation method. Our work is motivated by a clinical trial of a gene therapy where the functional outcomes are measured repeatedly throughout the trial.

Bayesian borrowing for basket trials with longitudinal outcomes

Basket trials are a novel clinical trial design in which a single intervention is investigated in multiple patient subgroups, or "baskets." They offer the opportunity to share information between subgroups, potentially increasing power to detect treatment effects. Basket trials offer several advantages over running a series of separate trials, including reduced sample sizes, increased efficiency, and reduced costs. Primarily, basket trials have been undertaken in Phase II oncology settings, but could be a promising design in other areas where a shared underlying biological mechanism drives different diseases. One such area is chronic aging-related diseases. However, trials in this area frequently have longitudinal outcomes, and therefore suitable methods are needed to share information in this setting. In this paper, we extend three Bayesian borrowing methods for a basket design with continuous longitudinal endpoints. We demonstrate our methods on a real-world dataset and in a simulation study where the aim is to detect positive basketwise treatment effects. Methods are compared with standalone analysis of each basket without borrowing. Our results confirm that methods that share information can improve power to detect positive treatment effects and increase precision over independent analysis in many scenarios. In highly heterogeneous scenarios, there is a trade-off between increased power and increased risk of type I errors. Our proposed methods for basket trials with continuous longitudinal outcomes aim to facilitate their applicability in the area of aging related diseases. Choice of method should be made based on trial priorities and the expected basketwise distribution of treatment effects.

Are longitudinal randomised controlled oral health trials properly analysed? A meta-epidemiological study

INTRODUCTION

Longitudinal designs with multiple outcome measurements are commonly encountered in oral health randomised controlled trials (RCTs). The aim of this meta epidemiological study was to assess whether optimal statistical analysis approaches have been used in longitudinal oral health RCTs.

DATA SOURCES

PubMed search was undertaken in September 2021 for longitudinal oral health RCTs with at least 3 repeated outcome measurements which have been published between 2016- 2020 in the highest impact general and specialty dental journals.

STUDY SELECTION

Study selection and data extraction were accomplished independently and in duplicate. The statistical methods undertaken in the selected articles were tabulated, and the association between study characteristics and use of optimal analyses were assessed using X² or Fisher's exact test and logistic regression.

RESULTS

Five hundred and five oral health RCTs were deemed eligible for inclusion. Of these, only 28.3% RCTs used optimal statistical analyses for a longitudinal trial design. For the trials with an optimal statistical approach, the most frequent test used was repeated measures analysis of variance (RM-ANOVA) followed by mixed effect models (MEM). The use of optimal statistical tests was predicated by the involvement of a statistician (OR: 2, 95% CI:1.27 - 3.18, p<0.01), the journal impact factor (OR:1.19, 95% CI;1.1 - 1.29), continent of first author (likelihood ratio test p=0.01), number of the authors (OR:1.22, 95% CI;1.12-1.3, p<0.001), protocol registration (OR: 1.48, 95%CI; 1 to 2.2, p=0.05), funding(OR:2.4, 95%CI; 1.6 - 3.7, p<0.001), and dental specialty (likelihood ratio test p<0.001).

CONCLUSIONS

Most longitudinal oral health RCTs did not use optimal statistical analyses. Greater awareness of optimal analyses used to assess longitudinal data reported in oral health trials is required to circumvent the reporting of suboptimal inferences, selective reporting and research waste.

CLINICAL SIGNIFICANCE

Further progress is required to avoid suboptimal statistical analyses and fully utilise the benefits of the repeated measurements over time in oral health RCTs.

The longer-term effects of access to HIV self-tests on HIV testing frequency in high-risk gay and bisexual men: follow-up data from a randomised controlled trial

Background

A wait-list randomised controlled trial in Australia (FORTH) in high-risk gay and bisexual men (GBM) showed access to free HIV self-tests (HIVSTs) doubled the frequency of HIV testing in year 1 to reach guideline recommended levels of 4 tests per year, compared to two tests per year in the standard-care arm (facility-based testing). In year 2, men in both arms had access to HIVSTs. We assessed if the effect was maintained for a further 12 months.

Methods

Participants included GBM reporting condomless anal intercourse or > 5 male partners in the past 3 months. We included men who had completed at least one survey in both year 1 and 2 and calculated the mean tests per person, based on the validated self-report and clinic records. We used Poisson regression and random effects Poisson regression models to compare the overall testing frequency by study arm, year and testing modality (HIVST/facility-based test).

Findings

Overall, 362 men completed at least one survey in year 1 and 343 in year 2. Among men in the intervention arm (access to HIVSTs in both years), the mean number of HIV tests in year 2 (3⋅7 overall, 2⋅3 facility-based tests, 1⋅4 HIVSTs) was lower compared to year 1 (4⋅1 overall, 1⋅7 facility-based tests, 2⋅4 HIVSTs) (RR:0⋅84, 95% CI:0⋅75-0⋅95, p=0⋅002), but higher than the standard-care arm in year 1 (2⋅0 overall, RR:1⋅71, 95% CI:1⋅48-1.97, p<0⋅001). Findings were not different when stratified by sociodemographic characteristics or recent high risk sexual history.

Interpretation

In year 2, fewer HIVSTs were used on average compared to year 1, but access to free HIVSTs enabled more men to maintain higher HIV testing frequency, compared with facility-based testing only. HIV self-testing should be a key component of HIV testing and prevention strategies.

Funding

This work was supported by grant 568971 from the National Health and Medical Research Council of Australia.

Do longitudinal orthodontic trials use appropriate statistical analyses? A meta-epidemiological study

BACKGROUND

In orthodontic trials, longitudinal designs with multiple outcome measurements over time are common. The aim of this epidemiological study was to examine whether optimal statistical analysis approaches have been used in longitudinal orthodontic trials.

METHODS

Pubmed was searched in August 2021 for longitudinal orthodontic trials with at least three time points of outcome assessment published in the 2017-20 period. Study selection and data extraction were done independently and in duplicate. The analysis approaches undertaken were tabulated and associations between study characteristics and the use of optimal analysis or not were assessed using Fisher's exact test and logistic regression.

RESULTS

One hundred forty-seven out of 563 unique records were deemed eligible for inclusion. Only 26.50% of these trials used an optimal statistical analysis for longitudinal data where the data structure is accounted for. None of the study characteristics except the statistical significance of the results were associated with the appropriateness of the statistical analysis. The odds of significant results in studies with suboptimal analyses were higher than that in studies with optimal longitudinal analyses (odds ratio: 3.48, 95% confidence interval: 1.62, 7.46, P = 0.001). For the studies with optimal analysis, the most frequent test was repeated-measure analysis of variance (RM-ANOVA). The reporting of the statistical analysis section was suboptimal in the majority of the trials.

CONCLUSION

Most longitudinal orthodontic trials are not analysed using optimal statistical approaches. Inferences and interpretation of their results are likely to be compromised.

A feasibility study of hyoscine butylbromide (buscopan) to improve image quality of cone beam computed tomography during abdominal/pelvic Stereotactic Ablative Radiotherapy

OBJECTIVES

Cone beam computed tomography (CBCT) is used for image guidance of stereotactic ablative radiotherapy (SABR), but it is susceptible to bowel motion artefacts. This trial evaluated the impact of hyoscine butylbromide (buscopan) on CBCT image quality and its feasibility within a radiotherapy workflow.

METHODS

A single-centre feasibility trial (ISRCTN24362767) was performed in patients treated with SABR for abdominal/pelvic oligorecurrence. Buscopan was administered to separate cohorts by intramuscular (IM) or intravenous (i.v.) injection on alternate fractions, providing within-patient control data. 4-point Likert scales were used to assess overall image quality (ranging from excellent to impossible to use) and bowel motion artefact (ranging from none to severe). Feasibility was determined by patient/radiographer questionnaires and toxicity assessment. Descriptive statistics are presented.

RESULTS

16 patients were treated (8 by IM and 8 by i.v. buscopan). The percentage of images of excellent quality with/without buscopan was 47 vs 29% for IM buscopan and 65 vs 40% for i.v. buscopan. The percentage of images with no bowel motion artefact with/without buscopan was 24.6 vs 8.9% for IM buscopan and 25.8 vs 7% for i.v. buscopan. Four patients (25%) reported dry mouth. 14 patients (93%) would accept buscopan as routine. 11 radiographers (92%) reported no delay in treatments.

CONCLUSIONS

A trend towards improved image quality/reduced bowel motion artefact was observed with IM/i.v. buscopan. Buscopan was well tolerated with limited impact on workflow.

ADVANCES IN KNOWLEDGE

This is the first trial of buscopan within a radiotherapy workflow. It demonstrated a trend to improved image quality and feasibility of use.

Effect of Berberine on Cardiovascular Disease Risk Factors: A Mechanistic Randomized Controlled Trial

Cardiovascular disease (CVD) is a major contributor to the global burden of disease. Berberine, a long-standing, widely used, traditional Chinese medicine, is thought to have beneficial effects on CVD risk factors and in women with polycystic ovary syndrome. The mechanisms and effects, specifically in men, possibly via testosterone, have not been examined previously. To assess the effect of berberine on CVD risk factors and any potential pathway via testosterone in men, we conducted a randomized, double-blind, placebo-controlled, parallel trial in Hong Kong. In total, 84 eligible Chinese men with hyperlipidemia were randomized to berberine (500 mg orally, twice a day) or placebo for 12 weeks. CVD risk factors (lipids, thromboxane A2, blood pressure, body mass index and waist–hip ratio) and testosterone were assessed at baseline, and 8 and 12 weeks after intervention. We compared changes in CVD risk factors and testosterone after 12 weeks of intervention using analysis of variance, and after 8 and 12 weeks using generalized estimating equations (GEE). Of the 84 men randomized, 80 men completed the trial. Men randomized to berberine had larger reductions in total cholesterol (−0.39 mmol/L, 95% confidence interval (CI) −0.70 to −0.08) and high-density lipoprotein cholesterol (−0.07 mmol/L, 95% CI −0.13 to −0.01) after 12 weeks. Considering changes after 8 and 12 weeks together, berberine lowered total cholesterol and possibly low-density lipoprotein-cholesterol (LDL-c), and possibly increased testosterone. Changes in triglycerides, thromboxane A2, blood pressure, body mass index and waist–hip ratio after the intervention did not differ between the berberine and placebo groups. No serious adverse event was reported. Berberine is a promising treatment for lowering cholesterol. Berberine did not lower testosterone but instead may increase testosterone in men, suggesting sex-specific effects of berberine. Exploring other pathways and assessing sex differences would be worthwhile, with relevance to drug repositioning and healthcare.

'Teaching: individual' to improve adherence in hypertension and type 2 diabetes

Educational interventions with a multifaceted approach have proven effective to improve adherence to therapeutic regimens in people with chronic diseases. The present study aimed to evaluate the efficacy of a nursing intervention involving individual teaching compared with usual care to improve adherence with therapeutic regimens in people with hypertension and/or type-2 diabetes mellitus (T2DM). This was a parallel randomised two-arm clinical trial in 200 patients from a primary care programme. After 6 months of follow-up, there was a significant improvement in treatment adherence with a score of 0.87 (95% CI 0.30 to 1.44) on a 13 point scale, and an average reduction in systolic blood pressure (SBP) of 3.79 mmHg (95% CI: -6.85 to -0.73) in the intervention group, but not in glycated haemoglobin (HbA1c) levels (-0.16% 95% CI: -0.41 to 0.09). The individual teaching intervention was effective in improving therapeutic adherence and improving blood pressure values among the participants from the primary care programme.

Conquering hypertension in Vietnam-solutions at grassroots level: study protocol of a cluster randomized controlled trial

Background

Vietnam has been experiencing an epidemiologic transition to that of a lower-middle income country with an increasing prevalence of non-communicable diseases. The key risk factors for cardiovascular disease (CVD) are either on the rise or at alarming levels in Vietnam, particularly hypertension (HTN). Inasmuch, the burden of CVD will continue to increase in the Vietnamese population unless effective prevention and control measures are put in place. The objectives of the proposed project are to evaluate the implementation and effectiveness of two multi-faceted community and clinic-based strategies on the control of elevated blood pressure (BP) among adults in Vietnam via a cluster randomized trial design.

Methods

Sixteen communities will be randomized to either an intervention (8 communities) or a comparison group (8 communities). Eligible and consenting adult study participants with HTN (n = 680) will be assigned to intervention/comparison status based on the community in which they reside. Both comparison and intervention groups will receive a multi-level intervention modeled after the Vietnam National Hypertension Program including education and practice change modules for health care providers, accessible reading materials for patients, and a multi-media community awareness program.

In addition, the intervention group only will receive three carefully selected enhancements integrated into routine clinical care: (1) expanded community health worker services, (2) home BP self-monitoring, and (3) a “storytelling intervention,” which consists of interactive, literacy-appropriate, and culturally sensitive multi-media storytelling modules for motivating behavior change through the power of patients speaking in their own voices. The storytelling intervention will be delivered by DVDs with serial installments at baseline and at 3, 6, and 9 months after trial enrollment. Changes in BP will be assessed in both groups at several follow-up time points. Implementation outcomes will be assessed as well.

Discussion

Results from this full-scale trial will provide health policymakers with practical evidence on how to combat a key risk factor for CVD using a feasible, sustainable, and cost-effective intervention that could be used as a national program for controlling HTN in Vietnam.

Trial registration

ClinicalTrials.gov NCT03590691. Registered on July 17, 2018. Protocol version: 6. Date: August 15, 2019.

Poisson–Tweedie mixed-effects model: A flexible approach for the analysis of longitudinal RNA-seq data

We present a new modelling approach for longitudinal overdispersed counts that is motivated by the increasing availability of longitudinal RNA-sequencing experiments. The distribution of RNA-seq counts typically exhibits overdispersion, zero-inflation and heavy tails; moreover, in longitudinal designs repeated measurements from the same subject are typically (positively) correlated. We propose a generalized linear mixed model based on the Poisson–Tweedie distribution that can flexibly handle each of the aforementioned features of longitudinal overdispersed counts. We develop a computational approach to accurately evaluate the likelihood of the proposed model and to perform maximum likelihood estimation. Our approach is implemented in the R package ptmixed, which can be freely downloaded from CRAN. We assess the performance of ptmixed on simulated data, and we present an application to a dataset with longitudinal RNA-sequencing measurements from healthy and dystrophic mice. The applicability of the Poisson–Tweedie mixed-effects model is not restricted to longitudinal RNA-seq data, but it extends to any scenario where non-independent measurements of a discrete overdispersed response variable are available.

Metabolic Effects of Late Dinner in Healthy Volunteers-A Randomized Crossover Clinical Trial

CONTEXT

Consuming calories later in the day is associated with obesity and metabolic syndrome. We hypothesized that eating a late dinner alters substrate metabolism during sleep in a manner that promotes obesity.

OBJECTIVE

The objective of this work is to examine the impact of late dinner on nocturnal metabolism in healthy volunteers.

DESIGN AND SETTING

This is a randomized crossover trial of late dinner (LD, 22:00) vs routine dinner (RD, 18:00), with a fixed sleep period (23:00-07:00) in a laboratory setting.

PARTICIPANTS

Participants comprised 20 healthy volunteers (10 male, 10 female), age 26.0 ± 0.6 years, body mass index 23.2 ± 0.7 kg/m2, accustomed to a bedtime between 22:00 and 01:00.

INTERVENTIONS

An isocaloric macronutrient diet was administered on both visits. Dinner (35% daily kcal, 50% carbohydrate, 35% fat) with an oral lipid tracer ([2H31] palmitate, 15 mg/kg) was given at 18:00 with RD and 22:00 with LD.

MAIN OUTCOME MEASURES

Measurements included nocturnal and next-morning hourly plasma glucose, insulin, triglycerides, free fatty acids (FFAs), cortisol, dietary fatty acid oxidation, and overnight polysomnography.

RESULTS

LD caused a 4-hour shift in the postprandial period, overlapping with the sleep phase. Independent of this shift, the postprandial period following LD was characterized by higher glucose, a triglyceride peak delay, and lower FFA and dietary fatty acid oxidation. LD did not affect sleep architecture, but increased plasma cortisol. These metabolic changes were most pronounced in habitual earlier sleepers determined by actigraphy monitoring.

CONCLUSION

LD induces nocturnal glucose intolerance, and reduces fatty acid oxidation and mobilization, particularly in earlier sleepers. These effects might promote obesity if they recur chronically.

Reducing Radiation Dermatitis Using a Film-forming Silicone Gel During Breast Radiotherapy: A Pilot Randomized-controlled Trial

BACKGROUND/AIM

To evaluate whether topical use of a film-forming silicone gel (StrataXRT®) could reduce radiation dermatitis compared to a moisturizing cream (X-derm®) in patients receiving whole breast radiotherapy.

PATIENTS AND METHODS

A total of 56 patients with breast cancer were randomized to use StrataXRT or X-derm. The severity of radiation dermatitis was graded using physiological skin parameters, clinician-assessed visual rating scales and patient-reported symptoms. Changes in these parameters from baseline to 4 weeks post-radiotherapy were evaluated every two weeks.

RESULTS

Two-way repeated-measures ANOVA revealed different patterns of changes in the erythema index (F=3.609, p=0.008) and melanin index (F=3.475, p=0.015). The post hoc analysis demonstrated a significantly lower erythema index and melanin index in the patients allocated to the StrataXRT group.

CONCLUSION

The use of StrataXRT can reduce radiation dermatitis with respect to objectively measured physiological skin parameters. The results of the present study will support the feasibility of conducting a larger randomized controlled trial.

Multicap to improve adherence after acute coronary syndromes: results of a randomized controlled clinical trial

BACKGROUND

Adherence to treatment after a myocardial infarction (MI) is poor, even in the early postinfarction period. Combining evidence-based drugs into a multicap could improve adherence in this population. No previous randomized trial assessing fixed-dose combination therapy has included patients early after a MI. We aimed to assess if a multicap containing four secondary prevention drugs increases adherence to treatment at 6 months after MI hospitalization. The study was designed as a randomized, parallel, open-label, controlled trial.

METHODS

Patients were randomized within 7 days of a MI to either multicap or control group. The multicap group received a capsule containing aspirin, atenolol, ramipril, and simvastatin. The control group received each drug in separate pills. The primary outcome was adherence at 6 months. We also measured blood pressure, heart rate, serum cholesterol levels, C-reactive protein, and platelet aggregation.

RESULTS

The study was stopped prematurely when 100 patients were included for futility. At 6 months, 92 (95.8%) patients were adherent to medical treatment: 98.0% in the multicap group and 93.5% in the control group [relative risk (RR) 1.05; 95% confidence interval (CI) 0.96-1.14; p = 0.347]. There were no differences between groups in systolic blood pressure (p = 0.662), diastolic blood pressure (p = 0.784), heart rate (p = 0.533), total cholesterol (p = 0.760), LDL-c (p = 0.979), C-reactive protein (p = 0.399), or in the proportion of patients with adequate platelet aggregation inhibition (p = 0.600).

CONCLUSIONS

The study did not find any improvement in the adherence at 6 months after a MI with a multicap-based strategy (Multicap for Increase Adherence After Acute Myocardial Infarction; [ ClinicalTrials.gov identifier: NCT02271178]).

Repeated Measures Designs and Analysis of Longitudinal Data: If at First You Do Not Succeed-Try, Try Again

Anesthesia, critical care, perioperative, and pain research often involves study designs in which the same outcome variable is repeatedly measured or observed over time on the same patients. Such repeatedly measured data are referred to as longitudinal data, and longitudinal study designs are commonly used to investigate changes in an outcome over time and to compare these changes among treatment groups. From a statistical perspective, longitudinal studies usually increase the precision of estimated treatment effects, thus increasing the power to detect such effects. Commonly used statistical techniques mostly assume independence of the observations or measurements. However, values repeatedly measured in the same individual will usually be more similar to each other than values of different individuals and ignoring the correlation between repeated measurements may lead to biased estimates as well as invalid P values and confidence intervals. Therefore, appropriate analysis of repeated-measures data requires specific statistical techniques. This tutorial reviews 3 classes of commonly used approaches for the analysis of longitudinal data. The first class uses summary statistics to condense the repeatedly measured information to a single number per subject, thus basically eliminating within-subject repeated measurements and allowing for a straightforward comparison of groups using standard statistical hypothesis tests. The second class is historically popular and comprises the repeated-measures analysis of variance type of analyses. However, strong assumptions that are seldom met in practice and low flexibility limit the usefulness of this approach. The third class comprises modern and flexible regression-based techniques that can be generalized to accommodate a wide range of outcome data including continuous, categorical, and count data. Such methods can be further divided into so-called “population-average statistical models” that focus on the specification of the mean response of the outcome estimated by generalized estimating equations, and “subject-specific models” that allow a full specification of the distribution of the outcome by using random effects to capture within-subject correlations. The choice as to which approach to choose partly depends on the aim of the research and the desired interpretation of the estimated effects (population-average versus subject-specific interpretation). This tutorial discusses aspects of the theoretical background for each technique, and with specific examples of studies published in Anesthesia & Analgesia, demonstrates how these techniques are used in practice.

"Teaching: Individual" to increase adherence to therapeutic regimen in people with hypertension and type-2 diabetes: protocol of the controlled clinical trial ENURSIN

Background

Worldwide, hypertension affects approximately 25% of the adult population and diabetes about 8.5%. Lack of adherence to prescribed treatment regimen remains a problem among patients undergoing long-term treatment, showing high non-adherence rates, at estimated range of between 36 and 93%. In our city, patients with hypertension and diabetes in primary care are looked after mainly by doctors with little nursing support; also, there is no published dataset among Colombian populations on the effect of nursing intervention to increase adherence to therapeutic regimen. The aim of this study was to evaluate the efficacy of nursing intervention "Teaching: Individual" compared with usual care, to increase adherence to therapeutic regimen in people with hypertension and/or type-2 diabetes, and to analyze the impact to glycosylated hemoglobin and systolic blood pressure levels.

Methods

A two-arm, single-blinded, randomized controlled trial, with participants allocated to either intervention group with "Teaching: Individual" provided by two nurses, or control group receiving routine care only. Two Hundred patients attending cardiovascular risk programs of Bucaramanga, Colombia were included. Nursing intervention consisted of six educational sessions about Coping Enhancement; Behavior Modification; Teaching: Disease Process, Prescribed Medication, Prescribed Diet and Prescribed Exercise. The outcomes were Treatment Behavior: Illness or Injury (adherence to treatment), levels of both glycosylated hemoglobin (HbA1c) and systolic blood pressure for 24 h, to be measured at baseline and two follow-up time points. Basic characteristics of the groups were compared through chi-square/Fisher's exact or Students-T/Mann-Whitney U test. Outcomes were evaluated with repeated data methods and investigated changes in the outcomes over time and to compare these changes among treatment groups, and statistical significance with p-value < 0.05 were considered.

Discussion

The nursing intervention "Teaching: Individual" to increase adherence to therapeutic regimen in people with hypertension and/or type-2 diabetes represents an innovative care approach intended for low-income population. The study will advise district health system policy makers and managers as to the efficacy of implementing this intervention. Should this intervention turn out efficacious, it can potentially achieve wide application in cardiovascular risk programs.

Trial registration

ENURSIN was registered in ClinicalTrials.gov (NCT02758275) on April 27, 2016, protocol number 01.

Effectiveness and cost-effectiveness of acupuncture with Doin therapy for chronic neck pain: a study protocol for a multicentre, randomised controlled clinical trial

INTRODUCTION

Doin therapy is a manual therapy used in Korean rehabilitation medicine. Recently, the use of acupuncture with Doin has increased in clinics and clinical trials have demonstrated its effects. However, well-designed studies examining the efficacy and cost-effectiveness of acupuncture with Doin therapy are rare.

METHODS AND ANALYSIS

This multicentre, assessor-blinded, randomised controlled trial with two parallel groups aims to evaluate the clinical effects and cost-effectiveness of acupuncture with Doin therapy. A total of 124 patients (with a neck pain duration of 6 months or longer and a Numeric Rating Scale ≥5) will be recruited at five Korean medicine hospitals. Patients will be randomly allocated to acupuncture with Doin therapy (n=62) and acupuncture alone (n=62) for 5 weeks of treatment. This study will be carried out with outcome assessor and statistician blinding. The primary outcome measure will consist of improvement in neck pain using the Visual Analogue Scale at 6 weeks. The secondary outcomes including measures of pain, functional disability, health-related quality of life and economic evaluation will be conducted at 6 weeks, and 3, 6, 9 and 12 months after treatment ETHICS AND DISSEMINATION: The project is approved by the Institutional Review Board (IRB) of the Jaseng Hospital of Korean Medicine and the Kyung Hee University Korean Medicine Hospital at Gangdong. Dissemination will occur after the findings from this study are published in other peer reviewed journals.

TRIAL REGISTRATION NUMBERS

NCT03558178; KCT0003068; Pre-results.

Impact of DARC rs12075 Variants on Liver Fibrosis Progression in Patients with Chronic Hepatitis C: A Retrospective Study

: The Duffy antigen receptor for chemokines (DARC) rs12075 polymorphism regulates leukocyte trafficking and proinflammatory chemokine homeostasis. Hepatitis C virus (HCV)-mediated liver fibrosis is associated with an uncontrolled inflammatory response. In this study, we evaluate the association between the DARC rs12075 polymorphism and liver stiffness progression in HCV-infected patients. We carried out a retrospective cohort study (repeated measures design) in 208 noncirrhotic patients with chronic hepatitis C (CHC) who had at least two liver stiffness measurements (LSM) with a separation of at least 12 months. We used generalized linear models to analyze the association between DARC rs12075 polymorphism and outcome variables. During a follow-up of 46.6 months, the percentage of patients with stages of fibrosis F0/F1 decreased (p < 0.001), while LSM values and the percentage of patients with cirrhosis increased (p < 0.001). This pattern of changes was maintained in each of the groups of patients analyzed according to their rs12075 genotypes (AA or AG/GG). However, the variations in liver stiffness characteristics were lower in patients with the rs12075 AG/GG genotype (AG/GG versus AA). Thereby, in the adjusted analysis, patients with the rs12075 AG/GG genotype had a lower risk of an increased value of LSM2/LSM1 arithmetic mean ratio (AMR = 0.83; p = 0.001) and of an increase in LSM ≥ 5 kPa (odds ratio (OR) = 0.28; p = 0.009). Besides, patients with rs12075 AG/GG had a lower risk of cirrhosis progression (OR = 0.24; p = 0.009). No significant associations were found for an increase in LSM ≥ 10 kPa. We found an association between the DARC rs12075 single nucleotide polymorphism (SNP) and CHC progression. Specifically, patients with the DARC rs12075 AG/GG genotype had a lower risk of liver fibrosis progression and development of cirrhosis.

Effect of selenium supplementation on changes in HbA1c: Results from a multiple-dose, randomized controlled trial

AIM

To investigate the effect of selenium supplementation at different dose levels on changes in HbA1c after 6 months and 2 years in a population of low selenium status.

MATERIALS AND METHODS

The Denmark PRECISE study was a single-centre, randomized, double-blinded, placebo-controlled, multi-arm, parallel clinical trial with four groups. In total, 491 volunteers aged 60 to 74 years were randomly assigned to treatment with 100, 200 or 300 μg selenium/day as selenium-enriched yeast or placebo-yeast. HbA1c measurements were available for 489 participants at baseline, 435 at 6 months, and 369 after 2 years of selenium supplementation. Analyses were performed by intention to treat.

RESULTS

The mean (SD) age, plasma-selenium concentration, and blood HbA1c at baseline were 66.1 (4.1) years, 86.5 (16.3) ng/g and 36.6 (7.0) mmol/mol, respectively. During the initial 6-month intervention period, mean HbA1c (95% CI) decreased by 1.5 (-2.8 to -0.2) mmol/mol for 100 μg/d of selenium supplementation and by 0.7 (-2.0 to 0.6) mmol/mol for the 200 and 300 μg/d groups compared with placebo (P = 0.16 for homogeneity of changes across the four groups). After 2 years of selenium supplementation, HbA1c had decreased significantly in all treatment groups, with no difference between active treatment and placebo.

CONCLUSIONS

Selenium supplementation in an elderly European population of low selenium status did not significantly affect HbA1c levels after 2 years. Our findings corroborate a possible U-shaped response of selenium supplementation on glucose metabolism.

The Myeloid-Epithelial-Reproductive Tyrosine Kinase (MERTK) rs4374383 Polymorphism Predicts Progression of Liver Fibrosis in Hepatitis C Virus-Infected Patients: A Longitudinal Study

Background: The myeloid-epithelial-reproductive tyrosine kinase (MERTK) is involved in hepatic steatosis, inflammation, and liver fibrosis. Here we evaluated the association between the MERTK rs4374383 single nucleotide polymorphism (SNP) and liver fibrosis progression in hepatitis C virus (HCV)-infected patients. Methods: We performed a retrospective study (repeated measures design) in 208 patients who had liver stiffness measurement (LSM), which was assessed using transient elastography. No patient had cirrhosis at baseline (LSM ≥ 12.5 kPa). Results: At baseline, 53.8% were male, the median age was 47.1 years, 13.5% reported a high intake of alcohol, 10.1% were prior injection drug users, 85.3% were infected with HCV genotype 1, and 22.6% had previously failed antiviral therapy (pegylated-interferon-alpha/ribavirin). During a median follow-up of 46.6 months, 26 patients developed cirrhosis. The rs4374383 G carriers had a higher risk of increasing LSM (adjusted arithmetic mean ratio (aAMR) = 1.14; p = 0.006) and a higher likelihood of having an increase in LSM greater than 5 kPa (ΔLSM ≥ 5 kPa) (adjusted odds ratio (aOR) = 2.37; p = 0.029), and greater than 7 kPa (ΔLSM ≥ 7 kPa) (aOR = 3.24; p = 0.032), after controlling for confounding. The SNP’s association with cirrhosis progression was close to statistical significance (aOR = 2.18; p = 0.070). Conclusions: MERTK rs4374383 A carriers had a lower risk of liver fibrosis progression than G carriers, supporting the hypothesis that this SNP seems to have a critical role in the pathogenesis of liver disease in HCV-infected patients.

Pan-Genotypic Hepatitis C Treatment with Glecaprevir and Pibrentasvir for 8 Weeks Resulted in Improved Cardiovascular and Metabolic Outcomes and Stable Renal Function: A Post-Hoc Analysis of Phase 3 Clinical Trials

Introduction

Chronic hepatitis C (CHC) infection is associated with extrahepatic manifestations (EHMs) which can affect renal, cardiovascular and other comorbidities. The effect of CHC treatment with short-duration regimens on these EHMs is not well defined. Hence, we examined longitudinal estimated glomerular filtration rate (eGFR), triglycerides and glucose values to assess the impact of short-duration CHC therapy on renal, cardiovascular and metabolic diseases, respectively.

Methods

We conducted analyses of all patients without cirrhosis treated with glecaprevir and pibrentasvir (G/P) for 8 weeks in two phase 3 clinical trials. In addition, one phase 3 trial was carried out to explore the effects of treatment on renal EHMs in patients with advanced renal impairment at baseline. As a sensitivity analysis, we included all CHC patients treated with G/P for 8 or 12 weeks enrolled across five phase 3 trials. Adjusting for baseline demographics and clinical properties via mixed regression models enabled evaluation of changes in EHMs through end of treatment.

Results

G/P treatment for 8 weeks resulted in statistically significant declines in triglycerides (− 28.6 mg/dl) and glucose (− 11.2 mg/dl), while there was no statistically significant decline in eGFR. Biomarker improvements were greatest among patients with elevated triglycerides and elevated glucose at baseline. Similar effects were observed across all patients treated with G/P for 8 or 12 weeks.

Conclusion

Short-duration treatment with G/P resulted in stable renal function and improvements in cardiovascular and metabolic EHM markers, especially in patients with severe EHMs at baseline.

Funding

AbbVie Inc.

Electronic supplementary material

The online version of this article (10.1007/s40121-018-0218-x) contains supplementary material, which is available to authorized users.

Effect of ombitasvir/paritaprevir/ritonavir + dasabuvir regimen on health-related quality of life for patients with hepatitis C

BACKGROUND & AIMS

This study analyses health-related quality of life data from 8 randomized clinical trials using ombitasvir/paritaprevir/ritonavir and dasabuvir ± ribavirin to investigate: (i) the impact of the treatment vs placebo during treatment on health-related quality of life; (ii) the sustainability of such treatment effect after 12-week treatment period; and (iii) if results from (i) and (ii) differ in subgenotypes 1a vs 1b.

METHODS

Six registration trials and 2 post-approval trials were pooled and analysed using longitudinal mixed models to estimate the effect of ombitasvir/paritaprevir/ritonavir and dasabuvir ± ribavirin on health-related quality of life outcomes adjusting for baseline scores, as well as patient demographics and clinical characteristics.

RESULTS

Patients treated with ribavirin-free ombitasvir/paritaprevir/ritonavir and dasabuvir regimen reported statistically significant increase in health-related quality of life outcomes as compared to placebo patients. While ombitasvir/paritaprevir/ritonavir and dasabuvir + ribavirin treatment saw statistically significant decline in health-related quality of life outcomes during treatment vs baseline and placebo, effect on health-related quality of life outcomes associated with ribavirin did not persist in the post-treatment period for ombitasvir/paritaprevir/ritonavir and dasabuvir patients followed for up to 52 weeks. The analysis also found Genotype 1b patients reported greater improvements in health-related quality of life as compared to genotype 1a patients.

CONCLUSIONS

During the active treatment period, small but statistically significant decrements in health-related quality of life outcomes were observed potentially driven by ribavirin, which were not sustained during the post-treatment follow-up period. Differences were observed by patient subgenotype, where health-related quality of life improvements were consistently higher for genotype 1b patients as compared to genotype 1a patients.

Analysis of randomised trials with long-term follow-up

Randomised trials with long-term follow-up can provide estimates of the long-term effects of health interventions. However, analysis of long-term outcomes in randomised trials may be complicated by problems with the administration of treatment such as non-adherence, treatment switching and co-intervention, and problems obtaining outcome measurements arising from loss to follow-up and death of participants. Methods for dealing with these issues that involve conditioning on post-randomisation variables are unsatisfactory because they may involve the comparison of non-exchangeable groups and generate estimates that do not have a valid causal interpretation. We describe approaches to analysis that potentially provide estimates of causal effects when such issues arise. Brief descriptions are provided of the use of instrumental variable and propensity score methods in trials with imperfect adherence, marginal structural models and g-estimation in trials with treatment switching, mixed longitudinal models and multiple imputation in trials with loss to follow-up, and a sensitivity analysis that can be used when trial follow-up is truncated by death or other events. Clinical trialists might consider these methods both at the design and analysis stages of randomised trials with long-term follow-up.

Simultaneous small-sample comparisons in longitudinal or multi-endpoint trials using multiple marginal models

Simultaneous inference in longitudinal, repeated-measures, and multi-endpoint designs can be onerous, especially when trying to find a reasonable joint model from which the interesting effects and covariances are estimated. A novel statistical approach known as multiple marginal models greatly simplifies the modelling process: the core idea is to "marginalise" the problem and fit multiple small models to different portions of the data, and then estimate the overall covariance matrix in a subsequent, separate step. Using these estimates guarantees strong control of the family-wise error rate, however only asymptotically. In this paper, we show how to make the approach also applicable to small-sample data problems. Specifically, we discuss the computation of adjusted P values and simultaneous confidence bounds for comparisons of randomised treatment groups as well as for levels of a nonrandomised factor such as multiple endpoints, repeated measures, or a series of points in time or space. We illustrate the practical use of the method with a data example.

Effect of Hepatitis C Treatment with Ombitasvir/Paritaprevir/R + Dasabuvir on Renal, Cardiovascular and Metabolic Extrahepatic Manifestations: A Post-Hoc Analysis of Phase 3 Clinical Trials

INTRODUCTION

We analyzed phase 3 trial data of ombitasvir/paritaprevir/ritonavir and dasabuvir (3D) ± ribavirin (RBV) in genotype 1 chronic hepatitis C patients to investigate the impact of 3D ± RBV on renal, cardiovascular and metabolic extrahepatic manifestations (EHMs), including persistency 52 weeks post treatment and differential impact by EHM disease severity.

METHODS

Estimated glomerular filtration rate (eGFR), fasting triglyceride and fasting glucose values from clinical trials were used to assess renal, cardiovascular and metabolic EHMs, respectively. Two placebo-controlled trials were used to study the effect of treatment, while the pooled sample of treated patients was used to study the persistency and differential effect of treatment by baseline EHM disease severity, as defined by baseline values of respective EHM biomarkers. Changes in EHM outcomes from baseline were assessed with mixed models adjusting for patient baseline demographic and clinical characteristics.

RESULTS

Treatment with 3D ± RBV resulted in statistically significant declines from baseline of triglycerides and glucose and no statistical change in eGFR. By 52 weeks post treatment patients with elevated triglycerides (-35.3 mg/dl), pre-diabetes (-4.4 mg/dl), diabetes (-34.2 mg/dl) and CKD stage 3 (+1.6 ml/min/1.73 m2) at baseline experienced a statistically significant improvement in their respective EHM values. Patients with CKD stages 2, 4 and 5 experienced no statistically significant change in eGFR from baseline.

CONCLUSION

Treatment with 3D ± RBV resulted in improvement or no worsening of cardiovascular, metabolic and renal EHM markers, especially in patients with severe EHMs at baseline, which persisted until 52 weeks post treatment.

FUNDING

Abbvie Inc.

Reprint of "Updating Markov models to integrate cross-sectional and longitudinal studies"

Clinical trials are typically conducted over a population within a defined time period in order to illuminate certain characteristics of a health issue or disease process. Cross-sectional studies provide a snapshot of these disease processes over a large number of people but do not allow us to model the temporal nature of disease, which is essential for modelling detailed prognostic predictions. Longitudinal studies, on the other hand, are used to explore how these processes develop over time in a number of people but can be expensive and time-consuming, and many studies only cover a relatively small window within the disease process. This paper explores the application of intelligent data analysis techniques for building reliable models of disease progression from both cross-sectional and longitudinal studies. The aim is to learn disease 'trajectories' from cross-sectional data by building realistic trajectories from healthy patients to those with advanced disease. We focus on exploring whether we can 'calibrate' models learnt from these trajectories with real longitudinal data using Baum-Welch re-estimation so that the dynamic parameters reflect the true underlying processes more closely. We use Kullback-Leibler distance and Wilcoxon rank metrics to assess how calibration improves the models to better reflect the underlying dynamics.

Obstructive Sleep Apnea Dynamically Increases Nocturnal Plasma Free Fatty Acids, Glucose, and Cortisol During Sleep

CONTEXT

Obstructive sleep apnea (OSA) is associated with diabetes and cardiovascular disease. This association may be related to metabolic changes that transpire during sleep in OSA.

OBJECTIVE

To examine the impact of OSA, elicited by cessation of continuous positive airway pressure (CPAP), on frequently sampled nocturnal metabolic markers including plasma free fatty acids (FFAs), glucose, insulin, triglycerides (TGs), cortisol, and lactate, as well as glucose production, oral glucose tolerance, blood pressure (BP), endothelial function, cholesterol, and high-sensitivity C-reactive protein (hsCRP).

DESIGN AND SETTING

Randomized crossover trial of CPAP vs CPAP withdrawal.

PATIENTS

Thirty-one patients with moderate to severe OSA acclimated to CPAP.

INTERVENTION

Patients underwent attended polysomnography while sleeping with therapeutic CPAP, or after CPAP withdrawal, in random order. Venous blood was sampled at ∼20-minute intervals on both nights. In 11 patients, we assessed glucose kinetics with an infusion of 6,6-[2H2]glucose.

RESULTS

CPAP withdrawal caused recurrence of OSA associated with hypoxemia, sleep disruption, and heart rate (HR) elevation. CPAP withdrawal dynamically increased nocturnal FFA (P = 0.007), glucose (P = 0.028), and cortisol (P = 0.037), in proportion to respiratory event frequency, HR elevation, or sleep fragmentation. Diabetes predisposed to glucose elevation. CPAP withdrawal also increased systolic BP (P = 0.017) and augmentation index (P = 0.008), but did not affect insulin, TGs, glucose production, oral glucose tolerance, cholesterol, or hsCRP.

CONCLUSION

OSA recurrence during CPAP withdrawal increases FFA and glucose during sleep, associated with sympathetic and adrenocortical activation. Recurring exposure to these metabolic changes may foster diabetes and cardiovascular disease.

Updating Markov models to integrate cross-sectional and longitudinal studies

Clinical trials are typically conducted over a population within a defined time period in order to illuminate certain characteristics of a health issue or disease process. Cross-sectional studies provide a snapshot of these disease processes over a large number of people but do not allow us to model the temporal nature of disease, which is essential for modelling detailed prognostic predictions. Longitudinal studies, on the other hand, are used to explore how these processes develop over time in a number of people but can be expensive and time-consuming, and many studies only cover a relatively small window within the disease process. This paper explores the application of intelligent data analysis techniques for building reliable models of disease progression from both cross-sectional and longitudinal studies. The aim is to learn disease 'trajectories' from cross-sectional data by building realistic trajectories from healthy patients to those with advanced disease. We focus on exploring whether we can 'calibrate' models learnt from these trajectories with real longitudinal data using Baum-Welch re-estimation so that the dynamic parameters reflect the true underlying processes more closely. We use Kullback-Leibler distance and Wilcoxon rank metrics to assess how calibration improves the models to better reflect the underlying dynamics.

TREAD: TReatment with Exercise Augmentation for Depression: study rationale and design

Background Despite recent advancements in the pharmacological treatment of major depressive disorder (MDD), over half of patients who receive treatment with antidepressant medication do not achieve full remission of symptoms. There is evidence that exercise can reduce depressive symptomatology when used as a treatment for MDD. However, no randomized controlled trials have evaluated exercise as an augmentation strategy for patients with carefully diagnosed MDD who remain symptomatic following an adequate acute phase trial of antidepressant therapy.

Purpose TReatment with Exercise Augmentation for Depression (TREAD) is an NIMH-funded, randomized, controlled trial designed to assess the relative efficacy of two doses of aerobic exercise to augment selective serotonin reuptake inhibitor (SSRI) treatment of MDD.

Methods The TREAD study includes 12 weeks of acute phase treatment with a 12-week post-treatment follow-up. In addition to looking at change in depressive symptoms as a primary outcome, it also includes comprehensive assessment of psychosocial function and treatment adherence.

Results This paper reviews the rationale and design of TREAD and illustrates how we address several key issues in contemporary patient-oriented research on MDD: 1) the use of augmentation strategies in the treatment of depressive disorders in general, 2) the use of non-pharmacological strategies in the treatment of depressive disorders, 3) the considerations of designing a well-controlled trial using two active treatment groups, and 4) the implementation of an adherence program for the use of exercise as a treatment strategy.

Conclusions The TREAD study is uniquely designed to overcome sources of potential bias and threats to internal and external validity that have limited prior research on the mental health effects of exercise. The study is facilitated by the development of a multidisciplinary research team that includes experts in both depression treatment and exercise physiology, as well as other related fields.

A flexible class of parametric transition regression models based on copulas: application to poliomyelitis incidence

This paper presents an extension of a general parametric class of transitional models of order p. In these models, the conditional distribution of the current observation, given the present and past history, is a mixture of conditional distributions, each of them corresponding to the current observation, given each one of the p-lagged observations. Such conditional distributions are constructed using bivariate copula models which allow for a rich range of dependence suitable to model non-Gaussian time series. Fixed and time varying covariates can be included in the models. These models have the advantage of straightforward construction and estimation for the analysis of time series and more general longitudinal data. A poliomyelitis incidence data set is used to illustrate the proposed methods, contrary to other researches’ conclusions whose methods are mainly based on linear models, we find significant evidence of a decreasing trend in polio infection after accounting for seasonality.

Incorrect statistical method in parallel-groups RCT led to unsubstantiated conclusions

The article by Aiso et al. titled “Compared with the intake of commercial vegetable juice, the intake of fresh fruit and komatsuna (Brassica rapa L. var perviridis) juice mixture reduces serum cholesterol in middle-aged men: a randomized controlled pilot study” does not meet the expected standards of Lipids in Health and Disease. Although the article concludes that there are some significant benefits to their komatsuna juice mixture, these claims are not supported by the statistical analyses used. An incorrect procedure was used to compare the differences in two treatment groups over time, and a large number of outcomes were tested without correction; both issues are known to produce high rates of false positives, making the conclusions of the study unjustified. The study also fails to follow published journal standards regarding clinical trial registration and reporting.

Rationale for the Assessment of Metoprolol in the Prevention of Vasovagal Syncope in Aging Subjects Trial (POST5)

BACKGROUND

Vasovagal syncope (VVS) is a common problem associated with a poor quality of life, which improves when syncope frequency is reduced. Effective pharmacological therapies for VVS are lacking. Metoprolol is a β-adrenergic receptor antagonist that is ineffective in younger patients, but may benefit older (≥40 years) VVS patients. Given the limited therapeutic options, a placebo-controlled clinical trial of metoprolol for the prevention of VVS in older patients is needed.

STRUCTURE OF STUDY

The POST5 is a multicenter, international, randomized, placebo-controlled study of metoprolol in the prevention of VVS in patients ≥40 years old. The primary endpoint is the time to first recurrence of syncope. Patients will be randomized 1:1 to receive metoprolol 25 to 100 mg BID or matching placebo, and followed up for 1 year. Secondary end points include syncope frequency, presyncope, quality of life, and cost analysis. Primary analysis will be intention to treat, with a secondary on-treatment analysis.

POWER CALCULATIONS

A sample size of 222, split equally between the groups achieves 85% power to detect a hazard rate of 0.3561 when the event rates are 50% and 30% in the placebo and metoprolol arms. Allowing for 10% dropout, we propose to enroll 248 patients.

IMPLICATIONS

This study will be the first adequately powered trial to determine whether metoprolol is effective in preventing VVS in patients ≥40 years. If effective, metoprolol may become the first line pharmacological therapy for these patients.

Common scientific and statistical errors in obesity research

This review identifies 10 common errors and problems in the statistical analysis, design, interpretation, and reporting of obesity research and discuss how they can be avoided. The 10 topics are: 1) misinterpretation of statistical significance, 2) inappropriate testing against baseline values, 3) excessive and undisclosed multiple testing and "P-value hacking," 4) mishandling of clustering in cluster randomized trials, 5) misconceptions about nonparametric tests, 6) mishandling of missing data, 7) miscalculation of effect sizes, 8) ignoring regression to the mean, 9) ignoring confirmation bias, and 10) insufficient statistical reporting. It is hoped that discussion of these errors can improve the quality of obesity research by helping researchers to implement proper statistical practice and to know when to seek the help of a statistician.

Impact of Magnesium L-Lactate on Occurrence of Ventricular Arrhythmias in Patients with Implantable Cardioverter Defibrillators: A Randomized, Placebo-Controlled Trial

Background:

We evaluated the antiarrhythmic efficacy and quality of life (QoL) impact of oral magnesium Llactate on patients with an implantable cardioverter defibrillator (ICD).

Methods:

This prospective, double-blind, placebo-controlled trial randomized 70 patients with an ICD to receive oral magnesium L-lactate 3 tablets twice daily (504mg elemental magnesium daily) or matching placebo for 12 months. Patients were seen at baseline, 12, 24, 36, and 52 weeks. The primary endpoints were the cumulative occurrence of ICD therapy [either shock or anti-tachycardia pacing (ATP)] or QoL between the groups.

Results:

Among the 70 randomized patients with a mean ± SD follow-up of 6.4 ± 4.1 months, 10 patients in the placebo group and 8 in the magnesium group experienced either ICD shock or ATP [HR 0.84, 95% CI 0.33 to 2.12; p=0.706]. Without significant arrhythmia suppression, only minimal effects on QoL were seen. Eighty six percent of all patients had serum intracellular magnesium deficiency.

Conclusion:

In our underpowered trial, patients with ICDs had intracellular magnesium deficiency but oral magnesium Llactate only nonsignificantly reduced the occurrence of ICD therapies and had little impact on HrQoL.

Randomised controlled trial of the effect of long-term selenium supplementation on plasma cholesterol in an elderly Danish population

Although cross-sectional studies have shown a positive association between Se and cholesterol concentrations, a recent randomised controlled trial in 501 elderly UK individuals of relatively low-Se status found that Se supplementation for 6 months lowered total plasma cholesterol. The Danish PRECISE (PREvention of Cancer by Intervention with Selenium) pilot study (ClinicalTrials.gov ID: NCT01819649) was a 5-year randomised, double-blinded, placebo-controlled trial with four groups (allocation ratio 1:1:1:1). Men and women aged 60-74 years (n 491) were randomised to 100 (n 124), 200 (n 122) or 300 (n 119) μg Se-enriched yeast or matching placebo-yeast tablets (n 126) daily for 5 years. A total of 468 participants continued the study for 6 months and 361 participants, equally distributed across treatment groups, continued for 5 years. Plasma samples were analysed for total and HDL-cholesterol and for total Se concentrations at baseline, 6 months and 5 years. The effect of different doses of Se supplementation on plasma lipid and Se concentrations was estimated by using linear mixed models. Plasma Se concentration increased significantly and dose-dependently in the intervention groups after 6 months and 5 years. Total cholesterol decreased significantly both in the intervention groups and in the placebo group after 6 months and 5 years, with small and nonsignificant differences in changes in plasma concentration of total cholesterol, HDL-cholesterol, non-HDL-cholesterol and total:HDL-cholesterol ratio between intervention and placebo groups. The effect of long-term supplementation with Se on plasma cholesterol concentrations or its sub-fractions did not differ significantly from placebo in this elderly population.

Meta-analysis of the predictive value of C-reactive protein for infectious complications in abdominal surgery

BACKGROUND

The aim of this analysis was to assess the predictive value of C-reactive protein (CRP) for the early detection of postoperative infectious complications after a variety of abdominal operations.

METHODS

A meta-analysis of seven cohort studies from a single institution was performed. Laparoscopic gastric bypass and colectomies, as well as open resections of cancer of the colon, rectum, pancreas, stomach and oesophagus, were included. The predictive value of CRP was assessed by the area under the curve (AUC) of the receiver operating characteristic (ROC) curve.

RESULTS

Of 1986 patients, 577 (29·1 (95 per cent c.i. 27·1 to 31·3) per cent) had at least one postoperative infectious complication. Patients undergoing laparoscopic gastric bypass (383 patients) or colectomy (285), and those having open gastric (97) or colorectal (934) resections were combined in a meta-analysis. Patients who had resection for cancer of the oesophagus (41) or pancreas (246) were analysed separately owing to heterogeneity. CRP levels 4 days after surgery had the highest diagnostic accuracy (AUC 0·76, 95 per cent c.i. 0·73 to 0·78). Sensitivity and specificity were 68·5 (60·6 to 75·5) and 71·6 (66·6 to 76·0) per cent respectively. Positive and negative predictive values were 50·4 (46·0 to 54·8) and 84·3 (80·8 to 87·3) per cent. The threshold CRP varied according to the procedure performed.

CONCLUSION

The negative predictive value of serum CRP concentration on day 4 after surgery facilitates reliable exclusion of postoperative infectious complications.

A test of lens opacity as an indicator of preclinical Alzheimer Disease

Previous studies reported that characteristic lens opacities were present in Alzheimer Disease (AD) patients postmortem. We therefore determined whether cataract grade or lens opacity is related to the risk of Alzheimer dementia in participants who have biomarkers that predict a high risk of developing the disease. AD biomarker status was determined by positron emission tomography-Pittsburgh compound B (PET-PiB) imaging and cerebrospinal fluid (CSF) levels of Aβ42. Cognitively normal participants with a clinical dementia rating of zero (CDR = 0; N = 40) or with slight evidence of dementia (CDR = 0.5; N = 2) were recruited from longitudinal studies of memory and aging at the Washington University Knight Alzheimer's Disease Research Center. The age, sex, race, cataract type and cataract grade of all participants were recorded and an objective measure of lens light scattering was obtained for each eye using a Scheimpflug camera. Twenty-seven participants had no biomarkers of Alzheimer dementia and were CDR = 0. Fifteen participants had biomarkers indicating increased risk of AD, two of which were CDR = 0.5. Participants who were biomarker positive were older than those who were biomarker negative. Biomarker positive participants had more advanced cataracts and increased cortical light scattering, none of which reached statistical significance after adjustment for age. We conclude that cataract grade or lens opacity is unlikely to provide a non-invasive measure of the risk of developing Alzheimer dementia.

Infliximab reverses inflammatory muscle wasting (sarcopenia) in Crohn's disease

BACKGROUND

Muscle wasting or sarcopenia arising from chronic inflammation is found in 60% of patients with Crohn's disease. Transcriptional protein NF-κB reduces muscle formation through MyoD transcription and increases muscle breakdown by proteolysis.

AIM

As TNF is a potent activator of NF-κB, and anti-TNF agent infliximab (IFX) prevents NF-κB activation, to determine whether or not Crohn's patients treated with IFX gain muscle volume and strength.

METHODS

We performed a prospective, repeated-measures cohort study in adult Crohn's disease patients with an acute disease flare. Patients were instructed not to vary diet or activity. Concomitant medications were kept stable. At week 1 (pre-treatment), week 16 (post-IFX induction) and week 25 (post-first IFX maintenance dose), we assessed (i) MRI volume of quadriceps femoris at anatomical mid-thigh; (ii) maximal concentric quadriceps contractions strength at three specific speeds of contraction; (iii) physical activity by validated instrument (IPAQ); (iv) Three-day food record of intake and composition (food-weighing method); (v) Serum levels of IL6.

RESULTS

Nineteen patients (58% female; mean age 33.2 ± 10.7 years) were recruited. IFX increased muscle volume in both legs from baseline (right, 1505 cm(3) ) to week 25 (right, 1569 cm(3) ; P = 0.010). IFX also increased muscle strength in both legs from baseline (right 30°/s, 184.8 Nm) to week 25 (right 30°/s, 213.6 Nm; P = 0.002). Muscle volume gain correlated with male gender (P = 0.003). Significant gains in muscle volume and strength were unrelated to prednisolone use. Serum IL6 levels decreased by week 25 (P = 0.037).

CONCLUSION

The anti-TNF agent infliximab reverses inflammatory sarcopenia in patients with Crohn's disease.

Statistical considerations for preclinical studies

Research studies must always have proper planning, conduct, analysis and reporting in order to preserve scientific integrity. Preclinical studies, the first stage of the drug development process, are no exception to this rule. The decision to advance to clinical trials in humans relies on the results of these studies. Recent observations show that a significant number of preclinical studies lack rigor in their conduct and reporting. This paper discusses statistical aspects, such as design, sample size determination, and methods of analyses, that will help add rigor and improve the quality of preclinical studies.

Selecting a separable parametric spatiotemporal covariance structure for longitudinal imaging data

Longitudinal imaging studies allow great insight into how the structure and function of a subject's internal anatomy changes over time. Unfortunately, the analysis of longitudinal imaging data is complicated by inherent spatial and temporal correlation: the temporal from the repeated measures and the spatial from the outcomes of interest being observed at multiple points in a patient's body. We propose the use of a linear model with a separable parametric spatiotemporal error structure for the analysis of repeated imaging data. The model makes use of spatial (exponential, spherical, and Matérn) and temporal (compound symmetric, autoregressive-1, Toeplitz, and unstructured) parametric correlation functions. A simulation study, inspired by a longitudinal cardiac imaging study on mitral regurgitation patients, compared different information criteria for selecting a particular separable parametric spatiotemporal correlation structure as well as the effects on types I and II error rates for inference on fixed effects when the specified model is incorrect. Information criteria were found to be highly accurate at choosing between separable parametric spatiotemporal correlation structures. Misspecification of the covariance structure was found to have the ability to inflate the type I error or have an overly conservative test size, which corresponded to decreased power. An example with clinical data is given illustrating how the covariance structure procedure can be performed in practice, as well as how covariance structure choice can change inferences about fixed effects.