Wang, M. Y.; Perera, M. P.; Fitzgerald, P. B.; Bailey, N.; Fitzgibbon, B. M.

Objective: Mindfulness-based interventions (MBIs) show promise in managing chronic pain but often require substantial time commitments, leading to high attrition rates and concerns about acceptability. This meta-analysis evaluated attrition rates in MBIs for chronic pain and explored factors contributing to participant withdrawal. Methods: Following PRISMA guidelines, 44 studies (45 intervention conditions) were analysed. Data on attrition rates, program characteristics (e.g., delivery method, group vs. individual therapy, session duration), and participant demographics were extracted. Meta-analyses of proportions assessed moderators influencing attrition rates. Results: The overall weighted mean attrition rate was 30.1% (95% CI: 24.5% to 37.3%) with substantial heterogeneity (I^2 = 89.0%). Stricter completion thresholds (defined as the minimum number of sessions required to be considered a programme completer) were associated with higher attrition (p < 0.001, R^2 = 28.1%), ranging from an 18% attrition rate for low thresholds (completion of 3 sessions or more required to be defined as a completer) to a 49.7% attrition rate for high thresholds (6 sessions or more). Online delivery showed higher attrition rates (51.0%) compared to in-person delivery (25.6%, p = 0.002, R^2 = 17.1%). Individually delivered MBIs were also linked to higher attrition compared to group formats (beta = 0.216, p = 0.039, R^2 = 5.5%). Conclusions: Attrition rates for MBIs in chronic pain management vary widely. Higher attrition is associated with stricter completion criteria, online delivery, and individual formats. These findings highlight the need to optimise MBI programme structure to reduce attrition in MBIs for chronic pain management.