Cost-effectiveness of flexible take-home buprenorphine-naloxone versus methadone for treatment of prescription-type opioid use disorder.

Background: Our objective was to examine the cost-effectiveness of flexible take-home buprenorphine-naloxone (BNX) versus methadone alongside the OPTIMA trial in Canada.

Methods: The OPTIMA study was a pragmatic, open-label, noninferiority, two-arm randomized controlled trial, to assess the comparative effectiveness of flexible take-home BNX vs. methadone in routine clinical care for individuals with prescription-type opioid use disorder. We evaluated cost-effectiveness using a semi-Markov cohort model. Probabilities of overdose were calibrated, accounting for fentanyl prevalence and other overdose risk factors such as naloxone availability. We considered health sector and societal cost perspectives, including costs (2020 CAD) for treatment, health resource use, criminal activity, and health state-specific preference weights as outcomes to calculate incremental cost-effectiveness ratios. Six-month and lifetime (3% annual discount rate) time-horizons were explored.

Results: Over a lifetime time horizon, individuals accumulated -0.144 [CI: -0.302, -0.025] incremental quality-adjusted life years (QALYs) in BNX compared with methadone. Incremental costs were -$2047 [CI: -$39,197, $24,250] from a societal perspective, and -$4549 [CI: -$6332, -$3001] from a health sector perspective. Over a six-month time-horizon, individuals accumulated 0.002 [credible interval (CI): -0.011, 0.016] incremental QALYs in BNX compared with methadone. Incremental costs were -$307 [CI: -$10,385, $8466] from a societal perspective and -$1111 [CI: -$1517, -$631] from a health sector perspective. BNX was dominated (costlier, less effective) in 49.7% of simulations when adopting a societal perspective over a lifetime time horizon.

Conclusions: Flexible take-home BNX was not cost-effective versus methadone over a lifetime time horizon, resulting from better treatment retention in methadone compared to BNX.