Unintended impacts of regulatory changes to British Columbia Methadone Maintenance Program on addiction and HIV-related outcomes: An interrupted time series analysis

Abstract

BackgroundIn February 2014, several regulatory reforms were introduced to the methadone maintenance treatment (MMT) program in British Columbia, Canada, including a switch to a ten-times more concentrated methadone formulation and restrictions in pharmacy delivery services. We evaluated possible unintended effects of these changes on illicit drug use patterns and HIV treatment outcomes among HIV-positive opioid users. MethodsData was drawn from ACCESS, a prospective community-recruited cohort of HIV-positive people who use illicit drugs in Vancouver, Canada. Interrupted Time Series Analyses were used to evaluate impacts of the policy change on monthly rates of MMT enrolment, illicit heroin injection, antiretroviral therapy (ART) adherence, and HIV viral suppression among HIV-positive opioid users between November 2012 and May 2015. ResultsA total of 331 HIV-positive opioid users were included. The MMT policy change led to a significant immediate 11.5% increase in heroin injection, and 15.9% drop in optimal ART adherence. A gradual increase in the prevalence of MMT enrolment after the policy change was also documented (0.9% per month). No changes in viral suppression rates were observed. ConclusionWe observed immediate increases in illicit heroin injection and decreases in ART adherence in the wake of regulatory changes to the local MMT program. These findings underscore the need to consider potential unintended effects of altering health programmes for vulnerable populations, the need to develop appropriate mitigation strategies, as well as to involve all relevant stakeholders in the planning and implementations of new policies.