A systematic review and meta-analysis of dropout rates from dialectical behaviour therapy in randomized controlled trials

Dropout is an important factor that may compromise the validity of findings from randomized controlled trials (RCTs) of dialectical behaviour therapy (DBT). We conducted a targeted meta-analytic review of dropout from RCTs of DBT, with the aims of (1) calculating average rates of dropout from DBT; (2) investigating factors that moderate dropout; (3) examining whether dropout rates from DBT differ to control interventions; (4) synthesising reasons for dropout. Forty RCTs of DBT met full inclusion criteria. The weighted mean dropout rate was 28.0% (95% CI = 23.6, 32.9). Dropout rates were not related to target disorder, dropout definition, delivery format, therapist experience, and therapist adherence. Unexpectedly, dropout rates were significantly higher in trials that offered telephone coaching and utilized a therapist consultation team. DBT dropout rates did not significantly differ to dropout rates from control interventions. Few trials reported reasons for dropout, and there was little consistency in the reported reasons. Findings suggest that over one in four patients drop out from DBT in RCTs. This review highlights the urgency for future trials to explicitly report detail pertaining to patient dropout, as this may assist in the development of strategies designed to prevent future dropouts in RCTs of DBT.