Dropout rates of in‐person psychosocial substance use disorder treatments: a systematic review and meta‐analysis

Background and Aims Relapse rates for psychosocial substance use disorder (SUD) treatments are high, and dropout is a robust predictor of relapse. This study aimed to estimate average dropout rates of in‐person psychosocial SUD treatments and to assess predictors of dropout. Design A comprehensive meta‐analysis of dropout rates of studies of in‐person psychosocial SUD treatment. Studies included randomized controlled trials (RCTs) and cohort studies. Setting Studies conducted anywhere in the world that examined SUD treatment and were published from 1965 to 2016, inclusive. Participants/cases One hundred and fifty‐one studies, 338 study arms and 299 dropout rates including 26 243 participants. Measurements Databases were searched for studies of SUD treatment that included an in‐person psychosocial component. Meta‐analyses and meta‐regressions were conducted to estimate dropout rates and identify predictors of dropout, including participant characteristics, facilitator characteristics and treatment characteristics. Pooled estimates were calculated with random‐effects analyses accounting for the hierarchical structure of study arms nested within studies. Findings The average dropout rate across all studies and study arms was 30.4% [95% confidence interval (CI) = 27.2–33.8 and 95% prediction interval (PI) = 6.25–74.15], with substantial heterogeneity (I2 = 93.7%, P