Pacing in posttraumatic stress disorder therapy: A meta-regression of treatment frequency and completion rates

The present study utilized posttraumatic stress disorder (PTSD) clinical trials repository data to analyze associations between treatment frequency (i.e., weekly or more than weekly) and completion outcomes across cognitive processing therapy (CPT), prolonged exposure (PE), and eye movement desensitization and reprocessing (EMDR). Covariates included treatment type, interactions between treatment type and treatment frequency, total number of treatment sessions, mean age, and study-level risk of bias. All studies that met the eligibility criteria were included with CPT, PE, and EMDR in a secondary analysis to evaluate patterns in operationalizing treatment completion. A total of 84 study arms (k = 66 studies) were included in the primary analysis. Compared to CPT, patients had slightly lower odds of completing PE, odds ratio (OR) = 0.73, 95% confidence interval (CI) [0.62, 0.86], but were twice as likely to complete EMDR, OR = 2.44, 95% CI [1.82, 3.27]. Increasing the frequency of PE doubled the odds of completion compared to CPT, OR = 2.15, 95% CI [1.55, 2.99]. A Frequency × Treatment interaction signal was nonsignificant for EMDR, OR = 1.61, 95% CI [0.96, 2.71]. Secondary outcomes revealed substantial heterogeneity in definitions of treatment completion, with only one third of all CPT, PE, and EMDR trial arms explicitly defining treatment completion as completing all treatment sessions. Future research should expand these findings to other modalities, as well as standardize operationalizations of treatment completion.