Does Type of Sponsorship of Randomized Controlled Trials Influence Treatment Effect Size Estimates in Rehabilitation: A Meta-Epidemiological Study

The influence of bias in randomized controlled trials on rehabilitation intervention effect estimates: what we have learned from meta-epidemiological studies

This study aimed to synthesize evidence from studies that addressed the influence of bias domains in randomized controlled trials on rehabilitation intervention effect estimates and discuss how these findings can maximize the trustworthiness of an RCT in rehabilitation. We screened studies about the influence of bias on rehabilitation intervention effect estimates published until June 2023. The characteristics and results of the included studies were categorized based on methodological characteristics and summarized narratively. We included seven studies with data on 227,806 RCT participants. Our findings showed that rehabilitation intervention effect estimates are likely exaggerated in trials with inadequate/unclear sequence generation and allocation concealment when using continuous outcomes. The influence of blinding was inconsistent and different from the rest of medical science, as meta-epidemiological studies showed overestimation, underestimation, or neutral associations for different types of blinding on rehabilitation treatment effect estimates. Still, it showed a more consistent pattern when looking at patient-reported outcomes. The impact of attrition bias and intention to treat has been analyzed only in two studies with inconsistent results. The risk of reporting bias seems to be associated with overestimation of treatment effects. Bias domains can influence rehabilitation treatment effects in different directions. The evidence is mixed and inconclusive due to the poor methodological quality of RCTs and the limited number and quality of studies looking at the influence of bias and treatment effects in rehabilitation. Further studies about the influence of bias in RCTs on rehabilitation intervention effect estimates are needed.

Rehabilitation Interventions for Complex Regional Pain Syndrome: An Overview of Systematic Reviews

OBJECTIVES

An increasing number of systematic reviews have been conducted on various conservative management of complex regional pain syndrome (CRPS) targeting different rehabilitation interventions and objectives. The intent of this article was to summarize and critically appraise the body of evidence on conservative management of the CRPS and to provide an overall picture of the current state of the literature.

METHODS

This study was an overview of systematic reviews on conservative treatments for CRPS. We conducted a literature search from inception to January 2023 in the following databases: Embase, Medline, CINAHL, Google Scholar, Cochrane Library, and Physiotherapy Evidence Database (PEDro). Two independent reviewers conducted study screening, data extraction, and methodological quality assessment (using AMSTAR-2). Qualitative synthesis was the preferred method for reporting the findings of our review. We calculated the corrected covered area index to account for the proportion of overlapping primary studies that were included in multiple reviews.

RESULT

We identified 214 articles, and a total of 9 systematic reviews of randomized controlled trials were eligible for inclusion. Pain and disability were the most common outcomes evaluated in the reviews. There were 6 (6/9; 66%) high-quality, 2 (2/9; 22%) moderate-quality, and 1 critically low-quality systematic review (1/9;11%), with the quality of the included trials ranging from very low to high. There was a large overlap across primary studies that were included in the systematic reviews (corrected covered area=23%). The findings of high-quality reviews support the effectiveness of mirror therapy (MT) and graded motor imagery (GMI) programs on pain and disability improvement in CRPS patients. The large effect size was reported for the effectiveness of MT on pain and disability (SMD:1.88 (95% CI: 0.73-3.02) and 1.30 (95% CI: 0.11-2.49), respectively) and the effectiveness of GMI program (GMIP) on pain and disability improvement (SMD: 1.36 (95% CI: 0.75-1.96) and 1.64 (95% CI: 0.53-2.74), respectively).

DISCUSSION

The evidence is in favor of adopting movement representation techniques, such as MT and GMI programs, for the treatment of pain and disability in patients with CRPS. However, this is based on a small body of primary evidence, and more research is required to generate conclusions. Overall, the evidence is not comprehensive or of sufficient quality to make definitive recommendations about the effectiveness of other rehabilitation interventions in improving pain and disability.

Commercial funding and estimated intervention effects in randomized clinical trials: Systematic review of meta-epidemiological studies

We investigated to which degree commercial funding is associated with estimated intervention effects in randomized trials. We included meta-epidemiological studies with published data on the association between commercial funding and results or conclusions of randomized trials. We searched five databases and other sources. We selected one result per meta-epidemiological study, preferably unadjusted ratio of odds ratios (ROR), for example, odds ratio(commercial funding)/odds ratio(noncommercial funding). We pooled RORs in random-effects meta-analyses (ROR <1 indicated exaggerated intervention effects in commercially funded trials), subgrouped (preplanned) by study aim: commercial funding per se versus risk of commercial funder influence. We included eight meta-epidemiological studies (264 meta-analyses, 2725 trials). The summary ROR was 0.95 (95% confidence interval 0.85-1.06). Subgroup analysis revealed a difference (p = 0.02) between studies of commercial funding per se, ROR 1.06 (0.95-1.17) and studies of risk of commercial funder influence, ROR 0.88 (0.79-0.97). In conclusion, we found no statistically significant association between commercial funding and estimated intervention effects when combining studies of commercial funding per se and studies of risk of commercial funder influence. A preplanned subgroup analysis indicated that trials with high risk of commercial funder influence exaggerated intervention effects by 12% (21%-3%), on average. Our results differ from previous theoretical considerations and findings from methodological studies and therefore call for confirmation. We suggest it is prudent to interpret results from commercially funded trials with caution, especially when there is a risk that the funder had direct influence on trial design, conduct, analysis, or reporting.

Selection, Confounding, and Attrition Biases in Randomized Controlled Trials of Rehabilitation Interventions: What Are They and How Can They Affect Randomized Controlled Trials Results? Basic Information for Junior Researchers and Clinicians

ABSTRACT

A thorough knowledge of biases in intervention studies and how they influence study results is essential for the practice of evidence-based medicine. The objective of this review was to provide a basic knowledge and understanding of the concept of biases and associated influence of these biases on treatment effects, focusing on the area of rehabilitation research. This article provides a description of selection biases, confounding, and attrition biases. In addition, useful recommendations are provided to identify, avoid, or control these biases when designing and conducting rehabilitation trials. The literature selected for this review was obtained mainly by compiling the information from several reviews looking at biases in rehabilitation. In addition, separate searches by biases and looking at reference lists of selected studies as well as using Scopus forward citation for relevant references were used. If not addressed appropriately, biases related to intervention research are a threat to internal validity and consequently to external validity. By addressing these biases, ensuring appropriate randomization, allocation concealment, appropriate retention techniques to avoid dropouts, appropriate study design and statistical analysis, among others, will generate more accurate treatment effects. Based on their impact on clinical results, a proper understanding of these concepts is central for researchers, rehabilitation clinicians, and other stakeholders working on this field.

Conducting a Systematic Review and Meta-analysis in Rehabilitation

ABSTRACT

Systematic reviews are reviews of the literature using a step-by-step approach in a systematic way. Meta-analyses are systematic reviews that use statistical methods to combine the included studies to generate an effect estimate. In this article, we summarize 10 steps for conducting systematic reviews and meta-analyses in the field of rehabilitation medicine: protocol, review team and funding, objectives and research question, literature search, study selection, risk of bias, data extraction, data analysis, reporting of results and conclusions, and publication and dissemination. There are currently 64,958 trials that contain the word "rehabilitation" in CENTRAL (the database of clinical trials in the Cochrane Library), only 1246 reviews, and 237 protocols. There is an urgent need for rehabilitation physicians to engage and conduct systematic reviews and meta-analysis of a variety of rehabilitation interventions. Systematic reviews have become the foundation of clinical practice guidelines, health technology assessments, formulary inclusion decisions and to guide funding additional research in that area.

Performance, Detection, Contamination, Compliance, and Cointervention Biases in Rehabilitation Research: What Are They and How Can They Affect the Results of Randomized Controlled Trials? Basic Information for Junior Researchers and Clinicians

ABSTRACT

Bias is a systematic error that can cause distorted results leading to incorrect conclusions. Intervention bias (i.e., contamination bias, cointervention bias, compliance bias, and performance bias) and detection bias are the most common biases in rehabilitation research. A better understanding of these biases is essential at all stages of research to enhance the quality of evidence in rehabilitation trials. Therefore, this narrative review aims to provide insights to the readers, clinicians, and researchers about contamination, cointervention, compliance, performance, and detection biases and ways of recognizing and mitigating them. The literature selected for this review was obtained mainly by compiling the information from several reviews looking at biases in rehabilitation. In addition, separate searches by biases and looking at reference lists of selected studies as well as using Scopus forward citation for relevant references were used.This review provides several strategies to guard against the impact of bias on study results. Clinicians, researchers, and other stakeholders are encouraged to apply these recommendations when designing and conducting rehabilitation trials.

Combining meta-epidemiological study datasets on commercial funding of randomised clinical trials: Database, methods, and descriptive results of the COMFIT study

Randomised trials are often funded by commercial companies and methodological studies support a widely held suspicion that commercial funding may influence trial results and conclusions. However, these studies often have a risk of confounding and reporting bias. The risk of confounding is markedly reduced in meta-epidemiological studies that compare fairly similar trials within meta-analyses, and risk of reporting bias is reduced with access to unpublished data. Therefore, we initiated the COMmercial Funding In Trials (COMFIT) study aimed at investigating the impact of commercial funding on estimated intervention effects in randomised clinical trials based on a consortium of researchers who agreed to share meta-epidemiological study datasets with information on meta-analyses and trials included in meta-epidemiological studies. Here, we describe the COMFIT study, its database, and descriptive results. We included meta-epidemiological studies with published or unpublished data on trial funding source and results or conclusions. We searched five bibliographic databases and other sources. We invited authors of eligible meta-epidemiological studies to join the COMFIT consortium and to share data. The final construction of the COMFIT database involves checking data quality, identifying trial references, harmonising variable categories, and removing non-informative meta-analyses as well as correlated meta-analyses and trial results. We included data from 17 meta-epidemiological studies, covering 728 meta-analyses and 6841 trials. Seven studies (405 meta-analyses, 3272 trials) had not published analyses on the impact of commercial funding, but shared unpublished data on funding source. On this basis, we initiated the construction of a combined database. Once completed, the database will enable comprehensive analyses of the impact of commercial funding on trial results and conclusions with increased statistical power and a markedly reduced risk of confounding and reporting bias.