Trans-diagnostic efficacy of mindfulness-based programs: An umbrella review of meta-analyses of randomized controlled trials

Introduction: To comprehensively evaluate meta-analyses (MAs) of randomized controlled trials (RCTs) that investigated associations between mindfulness-based programs (MBPs) and any mental and physical outcome. Methods: Three electronic databases (PubMed, Embase, and Cochrane Library) were systematically searched from inception to April 2022 for meta-analyses of RCTs investigating associations between mindfulness-based programs and health outcomes. We included 44 MAs (432 RCT), reporting on 204 meta-analytic comparisons. Methodological quality of individual primary studies was evaluated using the Assessing the Methodological Quality of Systematic Reviews (AMSTAR) assessment. Each MA has been reanalyzed using the random-effects model. Summary effect sizes and their confidence intervals for each outcome were estimated, along with prediction intervals. We also calculated I2, small study effects, and excess significance that are associated with heterogeneity and bias. The quality of evidence for every comparison has been rated using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) assessment. Results: Overall, the quality of RCTs included by MAs is very poor. Moderate evidence for the efficacy of MBPs is limited to the reduction of obsessive-compulsive symptoms, obsessive beliefs, and depressive symptoms among adults with obsessive-compulsive disorder. All other (i.e., 201) meta-analytic comparisons showed “low” or “very low” evidence. Discussion: Considering the economic interests that revolve around the mindfulness industry (estimated at around $4 billion every year), high-quality RCT studies and longer follow-up periods are needed. Our results are currently the most comprehensive and up-to-date and should urgently inform clinical guidelines