The Efficacy of Mindfulness-Based Programs: An Umbrella Review of Meta-Analyses of Randomized Controlled Trials.

Background: We aimed to comprehensively evaluate the efficacy, acceptability, and tolerability of mindfulness-based programs (MBPs) on physical and mental health outcomes across populations. Methods: We conducted a PRIOR-compliant umbrella review of systematic reviews with meta-analyses of RCTs on the efficacy of MBPs published on PubMed/Embase/Cochrane Library/CINAHL/PsycINFO until 08/10/2024 (PROSPERO=CRD42019155162), computing random-effect meta-analyses/confidence intervals/prediction interval/heterogeneity. Certainty of evidence was graded into high/moderate/low/very low according to Grading of Recommendations, Assessment, Development and Evaluation (GRADE). Quality was assessed with Assessing the Methodological Quality of Systematic Reviews (AMSTAR) and AMSTAR-PLUS Content. Results: 105 meta-analyses were included (AMSTAR high 56%, medium 44%; AMSTAR-PLUS Content medium 23%, low 77%). The mean duration of MBPs and follow-up were 7,65 and 22,6 weeks, respectively. No meta-analytic comparison was supported by high certainty, and 16 were supported by moderate certainty. Among them, in adults with breast cancer, MBPs outperformed pooled control conditions (i.e., treatment as usual and waiting list/no-treatment) regarding anxiety and depressive symptoms and health-related quality of life at the end of treatment and/or follow-up (standardized mean difference [SMD]=from 0.21 to 0.33). In adults with obsessive-compulsive disorder, MBPs outperformed pooled control conditions (i.e., active interventions and waiting list/no treatment) regarding obsessive-compulsive and depressive symptoms and mindfulness at the end of treatment (SMD=from 0.23 to 0.47). In adults with depressive symptoms, MBPs outperformed pooled control conditions (i.e., waiting list/no treatment and treatment as usual) regarding depressive symptoms at the end of treatment (SMD=0.69). Among medical students, MBPs outperformed pooled control conditions (i.e., active interventions and waiting list/no treatment) and waiting list/no treatment regarding stress, mindfulness, and well-being at the end of treatment and/or follow-up (SMD=from 0.28 to 0.71). Drop-out/adverse events were poorly reported. Conclusions: Moderate certainty of evidence supports MBPs to be effective in adults with breast cancer, obsessive-compulsive disorder, depressive symptoms, and medical students for several outcomes.