Posttraumatic Stress Disorder Treatment Dropout Among Military and Veteran Populations: A Systematic Review and Meta-Analysis.

High treatment dropout rates reported in recent literature have brought into question the effectiveness of trauma-focused posttraumatic stress disorder (PTSD) treatments among military populations. The aim of the current systematic review was to evaluate PTSD treatment dropout rates among military populations by treatment type and other study-level variables. We searched four databases as well as gray literature for randomized controlled trials that evaluated evidence-based PTSD treatments in samples of active duty personnel and/or veterans. In total, 26 studies were included in this review, with a total of 2,984 participants. We analyzed dropout rates across treatment types using multivariate meta-analysis. Across all forms of treatment, the aggregated dropout rate was 24.2%. Dropout percentages based on treatment type were 27.1% for trauma-focused treatments, 16.1% for non-trauma-focused treatments, and 6.8% for waitlist groups. We found substantial heterogeneity between studies that was not explained by military status or other study-level covariates. Summary risk ratios (RRs) comparing relative dropout between treatment groups indicated that trauma-focused treatment groups had a higher risk of dropout compared to non-trauma-focused treatments, RR = 1.60. The statistical heterogeneity of within-treatment dropout risk ratios was negligible. Dropout rates among military patients receiving trauma-focused therapies were only slightly higher than those reported in the literature among civilian populations and were not explained by study-level covariates.