Background and aim: Buprenorphine offers an alternative to methadone in the treatment of heroin dependence, and has the advantage of allowing alternate-day dosing. This study is the first to examine the cost effectiveness of buprenorphine as maintenance treatment for heroin dependence in a primary care setting using economic and clinical data collected within a randomised trial.
Study design and methods: The study was a randomised, open-label, 12-month trial of 139 heroin-dependent patients in a community setting receiving individualised treatment regimens of buprenorphine or methadone. Those who were currently on a methadone program (n = 57; continuing therapy subgroup) were analysed separately from new treatment recipients (n = 82; initial therapy subgroup). The study took a broad societal perspective and included health, crime and personal costs. Data on resource use and outcomes were a combination of clinical records and self report at interview. The main outcomes were incremental cost per additional day free of heroin use and per QALY. An analysis of uncertainty calculated the likelihood of net benefits for a range of acceptable money values of outcomes. All costs were in 1999 Australian dollars (DollarA).
Results: The estimated mean number of heroin-free days did not differ significantly between those randomised to methadone (225 [95% CI 91, 266]), or buprenorphine (222 [95% CI 194, 250]) over the year of the trial. Buprenorphine was associated with an average 0.03 greater QALYs over 52 weeks (not significant). The total cost was DollarA 17,736 (95% CI -DollarA 2981, DollarA 38,364) with methadone and DollarA 11,916 (95% CI DollarA 7697, DollarA 16,135) with buprenorphine; costs excluding crime were DollarA 4513 (95% CI DollarA 3495, DollarA 5531) and DollarA 5651 (95% CI DollarA 4202, DollarA 7100). With additional heroin-free days as the outcome, and crime costs included buprenorphine has a lower cost but less heroin-free days. If crime costs are excluded buprenorphine has a higher cost and worse outcome than methadone. With additional QALYs as the outcome, the cost effectiveness of buprenorphine is DollarA 39,404 if crime is excluded, but buprenorphine is dominant if crime is included.
Conclusions: The trial found no significant differences in costs or outcomes between methadone and buprenorphine maintenance in this particular setting. Although some of the results suggest that methadone may have a cost advantage, it is difficult to infer from the trial data that offering buprenorphine as an alternative would have a significant effect on total costs or outcomes. The point estimates of costs and outcomes suggest that buprenorphine may have an advantage in those initiating therapy. The confidence intervals were wide, however, and the likelihood of net benefits from substituting one treatment for another was close to 50%.