Cost-effectiveness implications of increasing the efficiency of the extended-release naltrexone induction process for the treatment of opioid use disorder: a secondary analysis

Background and Aims: In a US randomized-effectiveness trial comparing extended-release naltrexone (XR-NTX) with buprenorphine–naloxone (BUP-NX) for the prevention of opioid relapse among participants recruited during inpatient detoxification (CTN-0051), the requirement to complete opioid detoxification prior to initiating XR-NTX resulted in lower rates of initiation of XR-NTX (72% XR-NTX versus 94% BUP-NX). Design: This was a retrospective secondary analysis of CTN-0051 trial data, including follow-up data over 24–36 weeks. Setting: Eight community-based, inpatient-detoxification and follow-up outpatient treatment facilities in the United States. Participants: A total of 283 participants randomized to receive XR-NTX. Measurements: Efficiency was estimated using a multivariable generalized structural equation model to explore simultaneous determinants of XR-NTX induction and induction duration (detoxification + residential days). Cost-effectiveness was estimated from the health-care sector perspective and included expected costs and quality-adjusted life-years (QALYs). Findings: Treatment site was the only modifiable factor that simultaneously increased the likelihood of XR-NTX induction and decreased induction duration. Incorporating the higher predicted probability of XR-NTX induction, and fewer predicted days of detoxification and subsequent residential treatment into the cost-effectiveness framework, reduced the incremental average 24-week total cost of XR-NTX treatment from $5317 more than that of BUP-NX (P = 0.01) to a non-statistically-significant difference of $1016 (P = 0.63). QALYs gained remained similar across arms. Conclusion: Adopting an efficient model of extended-release naltrexone initiation could result in extended-release naltrexone and buprenorphine–naloxone being of comparable economic value from the health-care sector perspective over 24–36 weeks for patients seeking treatment for opioid use disorder at an inpatient detoxification facility.