Comparison of results from different imputation techniques for missing data from an anti-obesity drug trial

A service evaluation of more than 1 million self-funding adults attending a community weight management programme

Scaled interventions are required to address levels of overweight and obesity and reduce health inequalities. Little data is available on the effectiveness of community weight management programmes for participants self-selecting to attend across different socio-economic backgrounds. This analysis investigates 3, 6, and 12-month outcomes of adults joining a real-life community weight management programme. Weight, attendance and Indices of Multiple Deprivation (IMD) data from all fee-paying adults joining Slimming World in 2016 were collated. Data were analysed using descriptive and inferential statistics to determine predictors of weight loss. Mean BMI of 1 094 676 adults (7.6% male) was 33.0 ± 6.4 kg/m2. Mean % weight change at 3, 6, and 12 months was -5.0% ± 3.6%, -5.9% ± 5.2%, and -6.0% ± 5.8%. Those attending 75% sessions achieved greater weight loss with mean weight losses at 3, 6, and 12-months of 7.7% ± 3.3%, 11.3% ± 5.2%, and 14.1% ± 7.5%, respectively. Effect sizes from comparison of weight change between deprivation deciles were negligible, with similar outcomes in the most and least deprived deciles at 12-months (-5.7% ± 5.9% vs. -6.2% ± 5.9%). This service evaluation of more than 1 million adults attending a community weight management programme found they were able to achieve and/or maintain an average 6% weight loss at 12 months, with high attenders achieving >14% loss. Men and those with higher levels of deprivation were accessing the support and achieving significant weight losses. Slimming World as a real-life, scalable weight management programme is well placed to help adults manage their weight and address health inequalities.

Combined Effects of Glenohumeral Mobilization, Stretching, and Thoracic Manipulation on Shoulder Internal Rotation Range of Motion

Background/purpose

Interventions including posterior glenohumeral mobilizations (PGM), sleeper stretches, and thoracic manipulation are commonly used to address posterior shoulder tightness. The purpose of this study was to assess the effects of adding thoracic manipulation to PGM and sleeper stretches on passive range of motion (PROM), joint mobility, and infraspinatus electromyographic (EMG) activity in shoulders with decreased internal rotation (IR) PROM.

Design

Randomized Sequential Intervention Laboratory Study.

Methods

Forty individuals with clinically significant IR loss attended two study sessions. Participants were randomized to receive five 30 seconds bouts of either grade III PGM or sleeper stretching. Following a seven-day washout period, all participants attended a second session and received a prescriptive supine HVLA manipulation targeting the T3-4 segment, followed by the previously randomized intervention. Outcome measures included internal rotation PROM, horizontal adduction PROM, posterior glenohumeral joint translation assessed via ultrasound imaging, and EMG activity of the infraspinatus during a PGM. All outcome measures were assessed pre- and immediately post-intervention and compared statistically.

Results

There were significant within-group, but not between-group, differences for IR and horizontal adduction PROM following a single session of PGM or sleeper stretch. When combined with thoracic manipulation, significantly smaller within session changes of IR PROM were observed for both PGM (mean difference 4.4, p=0.017) and sleeper stretches (mean difference 6.4, p=0.0005). There were no significant between group differences for horizontal adduction PROM, humeral head translation, or EMG activity across all time points.

Discussion

Both GH posterior mobilizations and sleeper stretches improved IR and horizontal adduction PROM in a single session. The addition of thoracic manipulation prior to local shoulder interventions resulted in smaller gains of both IR and horizontal adduction ROM.

Level of evidence

Level 2.

Addressing Missing Data in GC × GC Metabolomics: Identifying Missingness Type and Evaluating the Impact of Imputation Methods on Experimental Replication

Missing data is a significant issue in metabolomics that is often neglected when conducting data preprocessing, particularly when it comes to imputation. This can have serious implications for downstream statistical analyses and lead to misleading or uninterpretable inferences. In this study, we aim to identify the primary types of missingness that affect untargeted metabolomics data and compare strategies for imputation using two real-world comprehensive two-dimensional gas chromatography (GC × GC) data sets. We also present these goals in the context of experimental replication whereby imputation is conducted in a within-replicate-based fashion─the first description and evaluation of this strategy─and introduce an R package MetabImpute to carry out these analyses. Our results conclude that, in these two GC × GC data sets, missingness was most likely of the missing at-random (MAR) and missing not-at-random (MNAR) types as opposed to missing completely at-random (MCAR). Gibbs sampler imputation and Random Forest gave the best results when imputing MAR and MNAR compared against single-value imputation (zero, minimum, mean, median, and half-minimum) and other more sophisticated approaches (Bayesian principal component analysis and quantile regression imputation for left-censored data). When samples are replicated, within-replicate imputation approaches led to an increase in the reproducibility of peak quantification compared to imputation that ignores replication, suggesting that imputing with respect to replication may preserve potentially important features in downstream analyses for biomarker discovery.

Feasibility and Potential Effectiveness of a Smartphone Zero-Time Exercise Intervention for Promoting Physical Activity and Fitness in Patients With Coronary Heart Disease: A Pilot Randomized Controlled Trial

Background

Zero-time Exercise (ZTEx), a simple strength- and stamina-enhancing physical activity (PA) requiring no extra equipment, can potentially increase PA and fitness. This pilot trial examined the feasibility and potential effectiveness of a smartphone ZTEx intervention to promote PA and fitness in patients with coronary heart disease (CHD).

Methods

A parallel-group assessor-blinded pilot randomized controlled trial was conducted on Chinese patients with stable coronary heart disease (CHD) in three cardiology clinics. The experimental group received a 15-min brief individual face-to-face session and a 12-week ZTEx instant messaging with 28 picture e-messages and a smartphone ZTEx application (ZTExApp). The control group received the same duration of individual session and number and format of e-messages, but the content was healthy eating and breathing exercise. The feasibility was assessed based on: attrition rate, usage, response rate and perception of the intervention. The outcome evaluation included primary outcome (PA), fitness, exercise self-efficacy and intention, perceived happiness and health, and quality of life. A linear mixed model was used with intention-to-treat analysis adjusting for sex, age and baseline values. A semi-structured interview was conducted to collect feedback from the experiment group.

Results

One hundred thirty-nine patients (mean age 59.8 ± 6.6; 71.2% male) were randomized to the experimental group (n = 70) or control group (n = 69), and 80% (56/70) and 82% (57/69) of patients completed the 12-week follow-up assessment, respectively. The attrition rate was 18.7%. The experimental group reported that ZTEx was feasible to integrate PA into their daily life and appreciated the picture e-messages, and 95% of them sent feedback to us, but only 19.6% (13/70) of the participants entered their PA information into the e-diary of the ZTExApp. The experimental group had a significantly greater increase in time spent walking [mean difference (95% CI): 155.3 (10.1, 300.4), P = 0.04, Cohen's d = 0.34] than the control group.

Conclusions

This pilot study showed using a brief ZTEx face-to-face session with picture e-messages empowered patients with CHD to integrate PA into daily life. Future definitive trials with a longer follow-up and a more user-friendly ZTExApp interface are necessary to determine the effectiveness of the smartphone ZTEx intervention in enhancing PA and related outcomes.

Trial Registration

The research protocol was registered at the Hong Kong University Clinical Trials Registry (HKUCTR) on 22 Jul 2016 (Study identifier: HKUCTR-2165) and was also retrospectively registered at the National Institutes of Health (identifier number: NCT03464331) on 14 March 2018.

Methodological survey of missing outcome data in an alteplase for ischemic stroke meta-analysis

OBJECTIVE

Recent national guidelines recommend alteplase treatment for ischemic stroke within 4.5 h of symptom-onset based on meta-analyses of randomized controlled clinical trials (RCT). A detailed description of missing outcome data (MOD) due to participant loss to follow-up has never been published. The objective of this study was to perform a methodlogical survey on missing outcome data in an alteplase for ischemic stroke meta-analysis.

MATERIALS AND METHODS

A methodological survey was performed on a chosen meta-analysis of alteplase for ischemic stroke RCTs that most closely aligns with recent national guideline recommendations. Data were collected to assess the number of participants lost to follow-up; differential lost to follow-up between allocation groups; baseline characteristics of those lost to follow-up; and the imputation methods used by individual trials and the chosen meta-analysis. The number of participants lost to follow-up was compared with the fragility index; and repeated for individually positive RCTs in the meta-analysis.

RESULTS

The methodological survey revealed a substantial degree of missing information regarding MOD in the chosen meta-analysis and in individual RCTs. Single imputation was exclusively used in all RCTs and in the meta-analysis. The number of participants lost to follow-up was greater than the fragility index in the chosen meta-analysis and individually positive component RCTs suggesting that MOD may impact the direction of the reported effect or effect size.

CONCLUSION

This methodological survey of an alteplase for ischemic stroke meta-analysis revealed MOD may be an important source of unrecognized bias. This survey highlights the need for sensitivity analyses using more robust methods of imputation.

Are patients who return for 10-year follow-up after AIS surgery different from those who do not?

PURPOSE

To evaluate the impact of patients lost to follow-up on outcomes of surgery for adolescent idiopathic scoliosis (AIS) at 10-year postoperative.

METHODS

Preoperative, 2-year, and 5-year postoperative demographic, radiographic, and SRS-22 data from a prospective multi-center registry were compared between patients with a 10-year follow-up visit versus those without. A second analysis utilized variables that were different between the groups, along with SRS scores, in a cohort of patients with preoperative, 2-, 5-, and 10-year postoperative SRS scores (complete cohort) to impute missing 10-year data (imputed cohort) utilizing Markov chain Monte Carlo simulation.

RESULTS

250 patients had 10-year follow-up (21%). Those with 10-year follow-up had a greater percentage of patients who underwent anterior procedures (p < 0.05). Radiographically, the groups were similar at all three time points. SRS-22 scores demonstrated slightly worse pain and function preoperatively and at 2 year in those lost to follow-up (effect size eta = 0.11-0.12), with no differences at 5 year. Imputed data analysis demonstrated similar trends over time in SRS-22 scores compared to the complete cohort for total score and all domains except pain. There was no significant difference in imputed versus complete 10-year SRS-22 scores (p > 0.05).

CONCLUSION

This study identified early differences between patients with 10-year follow-up and those without, though effect sizes were small and non-existent at 5 years. SRS-22 scores at 10 year between the complete and imputed data sets did not differ. Clinically relevant outcomes of the subset who followed-up at 10 year are likely generalizable to the entire eligible AIS population.

Missing Data Imputation – A Survey

Many real world datasets may contain missing values for various reasons. These incomplete datasets can pose severe issues to the underlying machine learning algorithms and decision support systems. It may result in high computational cost, skewed output and invalid deductions. Various solutions exist to mitigate this issue; the most popular strategy is to estimate the missing values by applying inferential techniques such as linear regression, decision trees or Bayesian inference. In this paper, the missing data problem is discussed in detail with a comprehensive review of the approaches to tackle it. The paper concludes with a discussion on the effectiveness of three imputation methods namely, imputation based on Multiple Linear Regression (MLR), Predictive Mean Matching (PMM) and Classification And Regression Tree (CART) in the context of subspace clustering. The experimental results obtained on real benchmark datasets and high-dimensional synthetic datasets highlight that, MLR based imputation method is more efficient on high-dimensional incomplete datasets.

A randomised controlled trial of the 5:2 diet

Objective

The 5:2 diet is a popular intermittent energy restriction method of weight management that awaits further evaluation. We compared the effects of one-off 5:2 instructions with the effects of one-off standard multicomponent weight-management advice; and also examined whether additional behavioural support enhances 5:2 adherence and efficacy compared to one-off instructions.

Methods

Three hundred adults with obesity were randomised to receive a Standard Brief Advice (SBA) covering diet and physical activity (N = 100); 5:2 self-help instructions (5:2SH) (N = 100); or 5:2SH plus six once-weekly group support sessions (N = 100). Participants were followed up for one year.

Results

Adherence to 5:2SH was initially high (74% at 6 weeks), but it declined over time (31% at 6 months and 22% at one year). 5:2SH and SBA achieved similar weight-loss at six months (-1.8kg (SD = 3.5) vs -1.7kg (SD = 4.4); b = 0.23, 95%CI:-0.79–1.27, p = 0.7) and at one year (-1.9kg (SD = 4.9) vs -1.8kg (SD = 5.7), b = 0.20, 95%CI:-1.21–1.60, p = 0.79), with 18% vs 15% participants losing ≥5% of their body weight with 5:2SH and SBA, respectively at one year (RR = 0.83, 95%CI:0.44–1.54, p = 0.55). Both interventions received positive ratings, but 5:2SH ratings were significantly higher. 5:2SH had no negative effect on fat and fiber intake and physical activity compared to SBA. Compared to 5:2SH, 5:2G generated a greater weight loss at 6 weeks (-2.3kg vs -1.5kg; b = 0.74, 95%CI:1.37–0.11, p = 0.02), but by one year, the difference was no longer significant (-2.6kg vs -1.9kg, p = 0.37; ≥5% body weight loss 28% vs 18%, p = 0.10).

Conclusions

Simple 5:2 advice and multicomponent weight management advice generated similar modest results. The 5:2 diet did not undermine other health behaviours, and it received more favourable ratings. Adding initial group support enhanced 5:2 adherence and effects, but the impact diminished over time. Health professionals who provide brief weight management advice may consider including the 5:2 advice as an option.

Trial registration

ISRCTN registry (ISRCTN79408248).

Efficacy of an exoskeleton-based physical therapy program for non-ambulatory patients during subacute stroke rehabilitation: a randomized controlled trial

BACKGROUND

Individuals requiring greater physical assistance to practice walking complete fewer steps in physical therapy during subacute stroke rehabilitation. Powered exoskeletons have been developed to allow repetitious overground gait training for individuals with lower limb weakness. The objective of this study was to determine the efficacy of exoskeleton-based physical therapy training during subacute rehabilitation for walking recovery in non-ambulatory patients with stroke.

METHODS

An assessor-blinded randomized controlled trial was conducted at 3 inpatient rehabilitation hospitals. Patients with subacute stroke (< 3 months) who were unable to walk without substantial assistance (Functional Ambulation Category rating of 0 or 1) were randomly assigned to receive exoskeleton-based or standard physical therapy during rehabilitation, until discharge or a maximum of 8 weeks. The experimental protocol replaced 75% of standard physical therapy sessions with individualized exoskeleton-based sessions to increase standing and stepping repetition, with the possibility of weaning off the device. The primary outcome was walking ability, measured using the Functional Ambulation Category. Secondary outcomes were gait speed, distance walked on the 6-Minute Walk Test, days to achieve unassisted gait, lower extremity motor function (Fugl-Meyer Assessment), Berg Balance Scale, Patient Health Questionnaire, Montreal Cognitive Assessment, and 36-Item Short Form Survey, measured post-intervention and after 6 months.

RESULTS

Thirty-six patients with stroke (mean 39 days post-stroke) were randomized (Exoskeleton = 19, Usual Care = 17). On intention-to-treat analysis, no significant between-group differences were found in the primary or secondary outcomes at post-intervention or after 6 months. Five participants randomized to the Exoskeleton group did not receive the protocol as planned and thus exploratory as-treated and per-protocol analyses were undertaken. The as-treated analysis found that those adhering to exoskeleton-based physical therapy regained independent walking earlier (p = 0.03) and had greater gait speed (p = 0.04) and 6MWT (p = 0.03) at 6 months; however, these differences were not significant in the per-protocol analysis. No serious adverse events were reported.

CONCLUSIONS

This study found that exoskeleton-based physical therapy does not result in greater improvements in walking independence than standard care but can be safely administered at no detriment to patient outcomes. Clinical Trial Registration The Exoskeleton for post-Stroke Recovery of Ambulation (ExStRA) trial was registered at ClinicalTrials.gov (NCT02995265, first registered: December 16, 2016).

Adapting cognitive bias modification to train healthy prospection

Prospection, the mental simulation of future events, has been theoretically linked to physical and mental health. Prior studies have found that prospection is malleable; however, no research to our knowledge has tested whether a scalable intervention explicitly targeting the simulation of positive future outcomes can lead to more generalized positive prospection, and enhance positive outlook and reduce distress. The current study tested a novel, web-based cognitive bias modification for interpretation (CBM-I) program designed to shift prospective bias towards more positive (as opposed to negative) representations of future outcomes among 172 participants selected for having a relatively negative baseline expectancy bias. Results showed that following CBM-I, participants in active training conditions exhibited more positive expectations about the future, and increased self-efficacy and growth mindset. Also, optimism increased and depression and anxiety symptoms decreased following active training, but this also occurred for the control condition. Analyses did not suggest that changes in positive expectations mediated changes in positive outlook outcomes. Results suggest that an online prospection intervention can lead to more positive expectations about future events and improve positive outlook, though open questions remain about what accounts for the training effects.

Consistently Modest Antidepressant Effects in Clinical Trials: the Role of Regulatory Requirements

Despite being widely heralded following their discovery, the effectiveness and clinical utility of antidepressants has been questioned, in part due to the release of several decades of regulatory trial data. Upon investigation, contemporary regulatory trials of antidepressants have demonstrated a nearly identical effect size (0.3) for the past 40 years, regardless of placebo response or attempts to improve trial design. In this review, we examine the historical methods of antidepressant trials and re-evaluate regulatory trial data over time and according to drug class (SSRIs, SNRIs, and atypicals) with the addition of two classes of antidepressants not previously analyzed: tricyclics used as active comparators and the recently-approved NMDA receptor antagonist, esketamine. We show that among these five classes of antidepressants there were no significant differences between effect sizes or percent symptom reduction. We suggest that within the context of a regulatory trial of antidepressants, effect sizes will remain modest (~0.3) regardless of class or novel drug mechanism, possibly due to regulatory changes to trial design and conduct following the Kefauver-Harris Act of 1962. We comment that the regulatory double-blind, parallel, placebo-controlled trial model is an artificial creation for a narrow purpose-designed to demonstrate simple superiority over placebo and to determine basic safety. We should be cautious of stretching trial results beyond their limited capacity to inform clinical practice as trials are not representative of real-world patients or medication management practices. There is a substantial need to develop more realistic models to evaluate the clinical utility of antidepressants.

Early Sepsis Prediction Using Ensemble Learning With Deep Features and Artificial Features Extracted From Clinical Electronic Health Records

OBJECTIVES

Sepsis is caused by infection and subsequent overreaction of immune system and will severely threaten human life. The early prediction is important for the treatment of sepsis. This report aims to develop an early prediction method for sepsis 6 hours ahead on the basis of clinical electronic health records.

DATA SOURCES

Challenge data are released by PhysioNet/Computing in Cardiology Challenge 2019 and obtained from ICU patients in three separate hospital systems. Part of the data from two datasets, including 40,336 subjects, are publicly available, and the remaining are used as hidden test set. A normalized utility score defined by the organizing committee is used for model performance evaluation.

STUDY SELECTION

The supervised machine learning is applied to tackle this challenge. Specifically, we establish the prediction model under the framework of ensemble learning by integrating the artificial features based on clinical prior knowledge of sepsis with deep features automatically extracted by long short-term memory neural network.

DATA EXTRACTION

Forty clinical variables, including eight vital signs, 26 laboratory values, and six demographics, were measured and recorded once an hour for each individual, and the binary label (0 or 1) was simultaneously provided for each item.

DATA SYNTHESIS

The proposed model was evaluated by 30-fold cross-validation. The sensitivity, specificity, and normalized utility score were 0.641 ± 0.022, 0.844 ± 0.007, and 0.401 ± 0.019 on publicly available datasets, respectively. The final normalized utility score our team (UCAS_DataMiner) has obtained was 0.313 on full hidden test set (0.406, 0.373, and -0.215 on test set A, B, and C, respectively).

CONCLUSIONS

We realized a 6-hour ahead early-onset prediction of sepsis on the basis of clinical electronic health record by ensemble learning. The results indicated the proposed model functioned well in the early prediction of sepsis. In particular, ensemble learning had a significant (p < 0.01) improvement than any single model in performance.

Extensive selective reporting of quality of life in clinical study reports and publications of placebo-controlled trials of antidepressants

BACKGROUND

Selective reporting of trial results is common.

OBJECTIVE

To study selective reporting in clinical study reports, company trial registers and publications of quality of life in placebo-controlled trials of antidepressants.

METHODS

We compared clinical study reports of four antidepressants (fluoxetine, duloxetine, paroxetine and sertraline) obtained from two European drug regulators, data from online company registers, and publications received or retrieved from Eli Lilly and GlaxoSmithKline. Pfizer was also contacted but did not provide any publications.

RESULTS

We included 15 trials (19,015 pages) and 4717 patients. Six trials had used SF-36, seven EQ-5D and two both instruments. Nine of the 15 CSRs (60%) displayed selective reporting. In the companies' online registers, there was selective reporting for all 15 trials (100%). We received 20 publications from Eli Lilly and retrieved six from the GlaxoSmithKline register. There was selective reporting in 24 of the 26 publications (92%). Despite extensive selective reporting, we found only small differences between placebo and active drugs.

CONCLUSIONS

Access to the full raw data from clinical trials and to case report forms for all patients are needed to evaluate the effect of antidepressants on quality of life. Regulatory agencies should refuse to approve drugs or new indications based on incomplete reporting.

A latent class based imputation method under Bayesian quantile regression framework using asymmetric Laplace distribution for longitudinal medication usage data with intermittent missing values

Evaluating the association between diseases and the longitudinal pattern of pharmacological therapy has become increasingly important. However, in many longitudinal studies, self-reported medication usage data collected at patients' follow-up visits could be missing for various reasons. These pieces of missing or inaccurate/untenable information complicate determining the trajectory of medication use and its complete effects for patients. Although longitudinal models can deal with specific types of missing data, inappropriate handling of this issue can lead to a biased estimation of regression parameters especially when missing data mechanisms are complex and depend upon multiple sources of variation. We propose a latent class-based multiple imputation (MI) approach using a Bayesian quantile regression (BQR) that incorporates cluster of unobserved heterogeneity for medication usage data with intermittent missing values. Findings from our simulation study indicate that the proposed method performs better than traditional MI methods under certain scenarios of data distribution. We also demonstrate applications of the proposed method to data from the Prospective Study of Outcomes in Ankylosing Spondylitis (AS) cohort when assessing an association between longitudinal nonsteroidal anti-inflammatory drugs (NSAIDs) usage and radiographic damage in AS, while the longitudinal NSAID index data are intermittently missing.

Effects of lorcaserin on cardiometabolic risk factors in overweight and obese patients: A systematic review and meta-analysis

WHAT IS KNOWN AND OBJECTIVE

Lorcaserin is a selective serotonin 2c receptor agonist approved as an anti-obesity agent. The additional cardiometabolic benefits associated with lorcaserin have not been conclusively established. The aim of the systematic review and meta-analysis is to examine the effects of lorcaserin on blood pressure, heart rate and other metabolic parameters in overweight and obese patients from randomized controlled clinical trials (RCTs).

METHODS

A literature search was conducted on PubMed, EMBASE and Cochrane Central using the search terms 'lorcaserin' and 'randomized controlled trials' without language restrictions. RCTs with a follow-up period of at least 24 weeks were included in the meta-analysis.

RESULTS AND DISCUSSION

Six studies with 9452 patients in the lorcaserin group and 9392 patients in the placebo group were included. Compared with placebo, lorcaserin not only reduced weight, BMI and waist circumference but also improved SBP, DBP, heart rate, LDL, triglycerides, fasting plasma glucose and HbA1c. Our findings suggest that lorcaserin has trivial though consistent and favourable effects on blood pressure, heart rate and metabolic syndrome.

WHAT IS NEW AND CONCLUSION

Lorcaserin improved all cardiometabolic parameters modestly in addition to its weight loss effect in overweight and obese patients. More research is needed to determine its long-term cardiovascular benefits.

DIABRISK-SL trial: further consideration of age and impact of imputations

Type 2 diabetes mellitus (T2DM) is a major cause of morbidity and mortality worldwide. Early interventions may help to delay or prevent onset of cardiometabolic endpoints of clinical importance to T2DM patients.Wijesuriya et al. (BMC Med 15:146, 2017) published results of a randomised controlled trial in Sri Lanka testing the effect of two lifestyle modification programmes of varying intensity in participants aged 5-40 years with risk factors for T2DM. The intervention measured the impact of the two programmes on the primary composite endpoint consisting of various predictors of cardiometabolic disease. The authors concluded that the more intensive programme significantly reduced the incidence of predictors of cardiometabolic disease. Further, they delivered a large-scale intervention with restricted resources with widespread acceptance as demonstrated by the high uptake rate. However, we believe that further analysis is required to fully understand the potential for benefit, particularly in relation to age, retention and missing data.

Influence of subsidies and promotional strategies on outcomes in a beneficiary-based commercial weight-loss programme

To determine whether initial engagement, continued participation, and weight loss vary by subsidy and promotional strategies in a beneficiary-based, commercial weight-loss programme. We conducted a retrospective analysis of data from 2013 to 2016. Our dependent variables included initial engagement (≥1 calls; ≥2 weights), coach calls and weight change. Our independent variables were subsidy strategy (total subsidy (n = 9) vs cost sharing (n = 3)) and combination of promotional-subsidy strategies (mixed campaign + total subsidy (n = 6) vs mass media + total subsidy (n = 3)). We used logistic and linear regression analyses adjusted for beneficiary factors and clustering by organization. From 12 participating organizations, 26 068 beneficiaries registered of which 6215 initially engaged. Cost sharing was associated with significantly greater initial engagement as compared to total subsidy (OR 3.73, P < 0.001); however, no significant between-group differences existed in calls or weight change. Mass media + total subsidy group had significantly greater calls and weight loss at 12 months compared to mixed campaign + total subsidy (-2.6% vs -1.8%, P = 0.04). Cost sharing may promote greater initial engagement, although does not contribute to better participation or weight loss relative to total subsidy. If organizations elect total subsidy, then pairing this strategy with a mass media campaign may promote greater participation and weight loss among beneficiaries.

General health checks in adults for reducing morbidity and mortality from disease

BACKGROUND

General health checks are common elements of health care in some countries. They aim to detect disease and risk factors for disease with the purpose of reducing morbidity and mortality. Most of the commonly used individual screening tests offered in general health checks have been incompletely studied. Also, screening leads to increased use of diagnostic and therapeutic interventions, which can be harmful as well as beneficial. It is therefore important to assess whether general health checks do more good than harm. This is the first update of the review published in 2012.

OBJECTIVES

To quantify the benefits and harms of general health checks.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, two other databases and two trials registers on 31 January 2018. Two review authors independently screened titles and abstracts, assessed papers for eligibility and read reference lists. One review author used citation tracking (Web of Knowledge) and asked trial authors about additional studies.

SELECTION CRITERIA

We included randomised trials comparing health checks with no health checks in adults unselected for disease or risk factors. We did not include geriatric trials. We defined health checks as screening for more than one disease or risk factor in more than one organ system.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed the risk of bias in the trials. We contacted trial authors for additional outcomes or trial details when necessary. When possible, we analysed the results with a random-effects model meta-analysis; otherwise, we did a narrative synthesis.

MAIN RESULTS

We included 17 trials, 15 of which reported outcome data (251,891 participants). Risk of bias was generally low for our primary outcomes. Health checks have little or no effect on total mortality (risk ratio (RR) 1.00, 95% confidence interval (CI) 0.97 to 1.03; 11 trials; 233,298 participants and 21,535 deaths; high-certainty evidence, I² = 0%), or cancer mortality (RR 1.01, 95% CI 0.92 to 1.12; 8 trials; 139,290 participants and 3663 deaths; high-certainty evidence, I² = 33%), and probably have little or no effect on cardiovascular mortality (RR 1.05, 95% CI 0.94 to 1.16; 9 trials; 170,227 participants and 6237 deaths; moderate-certainty evidence; I² = 65%). Health checks have little or no effect on fatal and non-fatal ischaemic heart disease (RR 0.98, 95% CI 0.94 to 1.03; 4 trials; 164,881 persons, 10,325 events; high-certainty evidence; I² = 11%), and probably have little or no effect on fatal and non-fatal stroke (RR 1.05 95% CI 0.95 to 1.17; 3 trials; 107,421 persons, 4543 events; moderate-certainty evidence, I² = 53%).

AUTHORS' CONCLUSIONS

General health checks are unlikely to be beneficial.

Many Flavors of Model-Based Meta-Analysis: Part II - Modeling Summary Level Longitudinal Responses

Meta-analyses typically assess comparative treatment response for an end point at specific timepoints across studies. However, during drug development, it is often of interest to understand the response time-course of competitor compounds for a variety of purposes. Examples of such application include informing study design and characterizing the onset, maintenance, and offset of action. This tutorial acts as a "points for consideration" document, reviews relevant literature, and fits a longitudinal model to an example dataset.

When and how should multiple imputation be used for handling missing data in randomised clinical trials - a practical guide with flowcharts

Background

Missing data may seriously compromise inferences from randomised clinical trials, especially if missing data are not handled appropriately. The potential bias due to missing data depends on the mechanism causing the data to be missing, and the analytical methods applied to amend the missingness. Therefore, the analysis of trial data with missing values requires careful planning and attention.

Methods

The authors had several meetings and discussions considering optimal ways of handling missing data to minimise the bias potential. We also searched PubMed (key words: missing data; randomi*; statistical analysis) and reference lists of known studies for papers (theoretical papers; empirical studies; simulation studies; etc.) on how to deal with missing data when analysing randomised clinical trials.

Results

Handling missing data is an important, yet difficult and complex task when analysing results of randomised clinical trials. We consider how to optimise the handling of missing data during the planning stage of a randomised clinical trial and recommend analytical approaches which may prevent bias caused by unavoidable missing data. We consider the strengths and limitations of using of best-worst and worst-best sensitivity analyses, multiple imputation, and full information maximum likelihood. We also present practical flowcharts on how to deal with missing data and an overview of the steps that always need to be considered during the analysis stage of a trial.

Conclusions

We present a practical guide and flowcharts describing when and how multiple imputation should be used to handle missing data in randomised clinical.

Electronic supplementary material

The online version of this article (10.1186/s12874-017-0442-1) contains supplementary material, which is available to authorized users.

The impact of methods to handle missing data on the estimated prevalence of dementia and mild cognitive impairment in a cross-sectional study including non-responders

OBJECTIVE

Although several statistical methods for adjusting for missing data have been developed and are widely applied in research, few studies have investigated these methods in adjusting for missingness in datasets that aim to estimate the prevalence of dementia. We attempted to develop a more feasible approach for handling missingness in a cross-sectional study among elderly.

METHODS

Five methods of estimating prevalence, including stratified weighting (SW), inverse-probability weighting (IPW), hot deck imputation (HDI), ordinal logistic regression (OLR) and multiple imputation (MI), were applied to handle the missing data yielded by a dataset that include 2231 non-responders.

RESULTS

Compared with the results of the complete case analysis, the differences in the prevalence rates of dementia and mild cognitive impairment (MCI) calculated by the prevalence-estimating methods after adjusting for non-responders were less than 7% and 6%, respectively. In contrast to the results of other methods, the estimated prevalence of dementia and MCI calculated by MI increased when more predictive factors were included, and the lowest rate of missing data was achieved using MI. Using the participants' ages, the cognitive screening sores and activity of daily life sores as predictive variables when correcting for missingness induced relatively larger effects on the estimated dementia prevalence.

CONCLUSIONS

When adjusting for missingness while estimating the prevalence of dementia in cross-sectional studies, a simple method, such as SW, is recommended when limited information is available, whereas MI is the preferred method when additional information is available. Further simulation studies are needed to determine the optimal approach.

Cancer patient age and family caregiver bereavement outcomes

PURPOSE

This study drew on life course theory to argue that the strains of cancer caregiving and bereavement are modified by the age of the patient. We expected that caregivers of middle-aged patients would be more distressed than caregivers of older patients.

METHODS

This panel study conducted 199 interviews with family caregivers of advanced cancer patients; first following diagnosis and again shortly after the patient's death.

RESULTS

Among caregivers of middle-aged patients (40-59), grief mediated the relationship between baseline caregiving and bereavement depressed mood, with grief increasing risk of depression in bereavement. Among caregivers of young-old patients (60-79), grief had a suppressor effect on the relationship between caregiving and bereavement depressed mood, showing greater distress during caregiving than at bereavement.

CONCLUSIONS

Caregiving for middle-aged cancer patients may increase the risk for severe grief and depression, whereas caregivers of young-old cancer patients appeared to experience relief at bereavement. After bereavement, continued observation may be warranted for caregivers of a middle-aged patient; grief, added to the ongoing demands of their lives (which may include those left behind by a middle-aged patient), may put such caregivers at risk for greater psychological and emotional distress.

Protocol for CHANGE: a randomized clinical trial assessing lifestyle coaching plus care coordination versus care coordination alone versus treatment as usual to reduce risks of cardiovascular disease in adults with schizophrenia and abdominal obesity

BACKGROUND

Life expectancy in patients with schizophrenia is reduced by 20 years for males and 15 years for females compared to the general population. About 60% of the excess mortality is due to physical illnesses, with cardiovascular disease being the single largest cause of death.

METHODS/DESIGN

The CHANGE trial is an investigator-initiated, independently funded, randomized, parallel-group, superiority, multi-centre trial with blinded outcome assessment. 450 patients aged 18 years or above, diagnosed with schizophrenia spectrum disorders and increased waist circumference, will be recruited and randomized 1:1:1 to 12-months interventions. We will compare the effects of 1) affiliation to the CHANGE team, offering a tailored, manual-based intervention targeting physical inactivity, unhealthy dietary habits, and smoking, and facilitating contact to their general practitioner to secure medical treatment of somatic comorbidity; versus 2) affiliation to a care coordinator who will secure guideline-concordant monitoring and treatment of somatic comorbidity by facilitating contact to their general practitioner; versus 3) treatment as usual to evaluate the potential add-on effects of lifestyle coaching plus care coordination or care coordination alone to treatment as usual. The primary outcome is the 10-year risks of cardiovascular disease assessed at 12 months after randomization.

DISCUSSION

The premature mortality observed in this vulnerable population has not formerly been addressed specifically by using composite surrogate outcomes for mortality. The CHANGE trial expands the evidence for interventions aiming to reduce the burden of metabolic disturbances with a view to increase life expectancy. Here, we present the trial design, describe the methodological concepts in detail, and discuss the rationale and challenges of the intermediate outcomes.

TRIAL REGISTRATION

Clinical Trials.gov NCT01585493 . Date of registration 27(th) of March 2012.

Exercise for treating patellofemoral pain syndrome

BACKGROUND

Patellofemoral pain syndrome (PFPS) is a common knee problem, which particularly affects adolescents and young adults. PFPS, which is characterised by retropatellar (behind the kneecap) or peripatellar (around the kneecap) pain, is often referred to as anterior knee pain. The pain mostly occurs when load is put on the knee extensor mechanism when climbing stairs, squatting, running, cycling or sitting with flexed knees. Exercise therapy is often prescribed for this condition.

OBJECTIVES

To assess the effects (benefits and harms) of exercise therapy aimed at reducing knee pain and improving knee function for people with patellofemoral pain syndrome.

SEARCH METHODS

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (May 2014), the Cochrane Central Register of Controlled Trials (2014, Issue 4), MEDLINE (1946 to May 2014), EMBASE (1980 to 2014 Week 20), PEDro (to June 2014), CINAHL (1982 to May 2014) and AMED (1985 to May 2014), trial registers (to June 2014) and conference abstracts.

SELECTION CRITERIA

Randomised and quasi-randomised trials evaluating the effect of exercise therapy on pain, function and recovery in adolescents and adults with patellofemoral pain syndrome. We included comparisons of exercise therapy versus control (e.g. no treatment) or versus another non-surgical therapy; or of different exercises or exercise programmes.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials based on pre-defined inclusion criteria, extracted data and assessed risk of bias. Where appropriate, we pooled data using either fixed-effect or random-effects methods. We selected the following seven outcomes for summarising the available evidence: pain during activity (short-term: ≤ 3 months); usual pain (short-term); pain during activity (long-term: > 3 months); usual pain (long-term); functional ability (short-term); functional ability (long-term); and recovery (long-term).

MAIN RESULTS

In total, 31 heterogeneous trials including 1690 participants with patellofemoral pain are included in this review. There was considerable between-study variation in patient characteristics (e.g. activity level) and diagnostic criteria for study inclusion (e.g. minimum duration of symptoms) and exercise therapy. Eight trials, six of which were quasi-randomised, were at high risk of selection bias. We assessed most trials as being at high risk of performance bias and detection bias, which resulted from lack of blinding.The included studies, some of which contributed to more than one comparison, provided evidence for the following comparisons: exercise therapy versus control (10 trials); exercise therapy versus other conservative interventions (e.g. taping; eight trials evaluating different interventions); and different exercises or exercise programmes. The latter group comprised: supervised versus home exercises (two trials); closed kinetic chain (KC) versus open KC exercises (four trials); variants of closed KC exercises (two trials making different comparisons); other comparisons of other types of KC or miscellaneous exercises (five trials evaluating different interventions); hip and knee versus knee exercises (seven trials); hip versus knee exercises (two studies); and high- versus low-intensity exercises (one study). There were no trials testing exercise medium (land versus water) or duration of exercises. Where available, the evidence for each of seven main outcomes for all comparisons was of very low quality, generally due to serious flaws in design and small numbers of participants. This means that we are very unsure about the estimates. The evidence for the two largest comparisons is summarised here. Exercise versus control. Pooled data from five studies (375 participants) for pain during activity (short-term) favoured exercise therapy: mean difference (MD) -1.46, 95% confidence interval (CI) -2.39 to -0.54. The CI included the minimal clinically important difference (MCID) of 1.3 (scale 0 to 10), indicating the possibility of a clinically important reduction in pain. The same finding applied for usual pain (short-term; two studies, 41 participants), pain during activity (long-term; two studies, 180 participants) and usual pain (long-term; one study, 94 participants). Pooled data from seven studies (483 participants) for functional ability (short-term) also favoured exercise therapy; standardised mean difference (SMD) 1.10, 95% CI 0.58 to 1.63. Re-expressed in terms of the Anterior Knee Pain Score (AKPS; 0 to 100), this result (estimated MD 12.21 higher, 95% CI 6.44 to 18.09 higher) included the MCID of 10.0, indicating the possibility of a clinically important improvement in function. The same finding applied for functional ability (long-term; three studies, 274 participants). Pooled data (two studies, 166 participants) indicated that, based on the 'recovery' of 250 per 1000 in the control group, 88 more (95% CI 2 fewer to 210 more) participants per 1000 recovered in the long term (12 months) as a result of exercise therapy. Hip plus knee versus knee exercises. Pooled data from three studies (104 participants) for pain during activity (short-term) favoured hip and knee exercise: MD -2.20, 95% CI -3.80 to -0.60; the CI included a clinically important effect. The same applied for usual pain (short-term; two studies, 46 participants). One study (49 participants) found a clinically important reduction in pain during activity (long-term) for hip and knee exercise. Although tending to favour hip and knee exercises, the evidence for functional ability (short-term; four studies, 174 participants; and long-term; two studies, 78 participants) and recovery (one study, 29 participants) did not show that either approach was superior.

AUTHORS' CONCLUSIONS

This review has found very low quality but consistent evidence that exercise therapy for PFPS may result in clinically important reduction in pain and improvement in functional ability, as well as enhancing long-term recovery. However, there is insufficient evidence to determine the best form of exercise therapy and it is unknown whether this result would apply to all people with PFPS. There is some very low quality evidence that hip plus knee exercises may be more effective in reducing pain than knee exercise alone.Further randomised trials are warranted but in order to optimise research effort and engender the large multicentre randomised trials that are required to inform practice, these should be preceded by research that aims to identify priority questions and attain agreement and, where practical, standardisation regarding diagnostic criteria and measurement of outcome.