Sample Size Reporting in Physical Therapy Exercise RCTs: A 2018-2023 Systematic Review

Objective: To systematically analyze the reporting status of four key sample-size estimation factors (significance level, statistical power, effect size, and attrition rate) in randomized controlled trials (RCTs) published between 2018 and 2023, focusing on exercise interventions for older, musculoskeletal, and neurological patients. Methods: Following PRISMA guidelines, literature searches were conducted across five major databases: PubMed, EMBASE, Cochrane Library, CINAHL, and Web of Science. The final analysis included 285 RCT-based studies, in which exercise interventions were applied to older, musculoskeletal, and neurological patients. Data extraction was performed by two independent reviewers. No risk-of-bias appraisal was conducted, because this study was a descriptive review of reporting practices. Results: In studies involving older patients, 59.3% reported a significance level, 67.8% reported a power, 26.3% reported an effect size, and 54.2% reported an attrition rate. In musculoskeletal studies, 62.2% specified a significance level, 65.9% reported a power, 26.8% reported an effect size, and 36.6% reported an attrition rate. In neurological studies, 61.6% reported a significance level, 66.3% reported a power, 22.1% reported an effect size, and 45.3% reported an attrition rate. Between 22.9% and 30.2% of studies across all groups failed to report all four sample-size factors. Conclusions: This study highlights that there has been inadequate reporting of sample-size estimation factors in RCTs on exercise interventions for older, musculoskeletal, and neurological patients. Clear reporting of these factors is essential to improve the transparency of study design and to enhance the reliability of study outcomes.