To evaluate the impact of bias-related study characteristics on treatment effects in osteoarthritis (OA) trials.
Based on OA trials included in Cochrane reviews, the impact of study characteristics on treatment effect estimates was evaluated. Characteristics included items of the risk of bias (RoB) tool, trial size, single vs. multisite, and source of funding. Effect sizes (ESs) were calculated as standardized mean differences (SMDs). Meta-regression was performed to identify "relevant study-level covariates" that decrease the between-study variance (τˆ
Twenty reviews, including 126 OA trials with a high degree of heterogeneity, were included (τˆ
In musculoskeletal reviews addressing pain, all the items included in the Cochrane RoB tool might not be equally important. OA trial results may be affected by bias constructs that are not yet fully elucidated.