Treatment retention among patients randomized to buprenorphine/naloxone compared to methadone in a multi-site trial.

This secondary analysis of data from National Drug Abuse Treatment Clinical Trials Network protocol CTN-0027 (“Starting Treatment with Agonist Replacement Therapies (START)”) is the first large scale randomized trial that provides the opportunity to compare the treatment retention of participants on buprenorphine and methadone in community treatment programs in the U.S. It examined patient and medication characteristics associated with retention and continued illicit opioid use in methadone (MET) versus buprenorphine/naloxone (BUP) treatment for opioid dependence. The analysis included 1,267 opioid-dependent individuals participating in 9 opioid treatment programs between 2006 and 2009 and randomized to receive open-label BUP or MET for 24 weeks. The analyses included measures of patient characteristics at baseline (demographics; use of alcohol, cigarettes, and illicit drugs; self-rated mental and physical health), medication dose and urine drug screens during treatment, and treatment completion and days in treatment during the 24 week trial. The treatment completion rate was 74% for MET vs. 46% for BUP; the rate among MET participants increased to 80% when the maximum MET dose reached or exceeded 60mg/day. With BUP, the completion rate increased linearly with higher doses, reaching 60% with doses of 30-32mg/day. Of those remaining in treatment, positive opioid urine results were significantly lower among BUP relative to MET participants during the first 9 weeks of treatment. Higher medication dose was related to lower opiate use, more so among BUP patients. A Cox proportional hazards model revealed factors associated with dropout: (1) BUP (vs. MET), (2) lower medication dose (<16mg for BUP, <60mg for MET), (3) the interaction of dose and treatment condition (those with higher BUP dose were 1.04 times more likely to drop out than those with lower MET dose, and (4) being younger, Hispanic, and using heroin or other substances during treatment.

Conclusions: Provision of methadone appears to be associated with better retention in treatment for opioid dependence than buprenorphine, as does provision of higher doses of both medications. Provision of buprenorphine is associated with lower continued use of illicit opioids. The high dropout rates at the early phase of buprenorphine treatment suggest the need for early interventions to prevent dropout. Further study of factors/strategies influencing buprenorphine retention is needed.

Related protocols: CTN-0027