Twenty-one studies (2,703 participants, range 16 to 472) were included in the meta-analysis. Patients who received higher doses of buprenorphine had significantly greater retention in treatment than those on lower doses (69% versus 51%, p=0.006).
Retention in treatment: Buprenorphine dose and urine drug screens were significant predictors for retention status in the univariate analysis. Both remained statistically significant in the multivariate analysis. A higher dose had better retention (p=0.009) and positive urine drug screens for opiates predicted dropping out of treatment (p=0.01).
Illicit opioid use: Buprenorphine dose, retention in treatment and urine drug screens for cocaine use were significant predictors for illicit opioid use in the univariate analysis. Retention in treatment and urine drug screens for cocaine remained statistically significant in the multivariate analysis. Better retention in treatment predicted less illicit opioid use (p=0.033) and positive urine drug screens for cocaine predicted more illicit opioid use (p=0.021).