Exploration of dose tapering strategies for methadone maintenance treatment based on relapse risks: A subpopulation treatment effect pattern plot (STEPP) analysis.

Background: Half of methadone maintenance treatment (MMT) participants experience a tapering phase, however, the guidelines vary from country to country and lack individualized strategies based on relapse risk. A detailed and individualized tapering strategy is needed in China. This study aims to explore dose tapering strategies for Chinese individuals with different relapse risks.

Methods: A retrospective study was conducted from 2006 to 2017 at nine MMT clinics in Guangdong, China, involving 549 participants. The end point was the first relapse within 12 months of the start of tapering. Relapse risks before tapering for each participant were determined from a Cox model.

Results: Out of 549 participants, 173 (31.5 %) relapsed within 12 months after tapering. Findings indicated that a taper dose of less than 5 mg/week is better than other taper doses. Subpopulation treatment effect pattern plot (STEPP) methodology revealed different tapering strategies benefit participants according to relapse risk before tapering. Overall, findings indicated that a less than 5 mg/week reduction in MMT dose is better than reductions of other amounts. For participants with a low relapse risk before tapering, a reduction of less than 2.5 mg/week in MMT dose is better than a 2.5-5 mg/week reduction.

Conclusions: A taper dose of less than 5 mg/week appears to be the best dose tapering strategy for Chinese participants. Furthermore, for participants with a low relapse risk, a more gradual taper dose (less than 2.5 mg/week) works better than 2.5-5 mg/week. This benefit was not seen in participants with a high relapse risk before tapering.