No abstract

Randomized clinical trials attempt to reduce bias and create similar groups at baseline to infer causal effects. In meta-analyses, baseline imbalance may threaten the validity of the treatment effects. This meta-epidemiological study examined baseline imbalance in comparisons of exercise and antihypertensive medicines. Baseline data for systolic blood pressure, diastolic blood pressure, and age were extracted from a network meta-analysis of 391 randomized trials comparing exercise types and antihypertensive medicines. Fixed-effect meta-analyses were used to determine the presence of baseline imbalance and/or inconsistency. Meta-regression analyses were conducted on sample size, the risk of bias for allocation concealment, and whether data for all randomized participants were presented at baseline. In one exercise comparison, the resistance group was 0.3 years younger than the control group (95% confidence interval 0.6 to 0.1). Substantial inconsistency was observed in other exercise comparisons. Less data were available for medicines, but there were no occurrences of baseline imbalance and only a few instances of inconsistency. Several moderator analyses identified significant associations. We identified baseline imbalance as well as substantial inconsistency in exercise comparisons. Researchers should consider conducting meta-analyses of key prognostic variables at baseline to ensure balance across trials.

OBJECTIVE: To determine the effect of exercise on pain self-efficacy in adults with nonspecific chronic low back pain (NSCLBP). DESIGN: Intervention systematic review with meta-analysis LITERATURE SEARCH: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, Embase, PsycINFO, and CINAHL databases from October 20, 2018, to March 23, 2022. SELECTION CRITERIA: We included randomized controlled trials that compared the effect of exercise on pain self-efficacy to control, in adults with NSCLBP. DATA SYNTHESIS: We conducted a meta-analysis using a random-effects model. We evaluated the risk of bias using the Cochrane risk-of-bias tool (RoB 2) and judged the certainty of evidence using the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) framework. RESULTS: Seventeen trials were included, of which eight (n = 1121 participants; 60.6% female; mean age: 49.6 years) were included in the meta-analysis. Exercise increased pain self-efficacy by 3.02 points (95% confidence interval: 1.72, 4.32) on the 60-point Pain Self-Efficacy Questionnaire. The certainty of evidence was moderate; all trials were at high risk of bias. CONCLUSION: There was moderate-certainty evidence that exercise increased pain self-efficacy in adults with NSCLBP. Future research should investigate if this effect is meaningful, whether it increases with more targeted treatments to enhance pain self-efficacy, and the effects on outcomes for adults with NSCLBP. J Orthop Sports Phys Ther 2023;53(6):335–342. Epub: 10 May 2023. doi:10.2519/jospt.2023.11622