Methadone treatment, severe food insecurity, and HIV-HCV co-infection: A propensity score matching analysis

Background: Severe food insecurity (FI) is common among individuals living with HIV-hepatitis C virus (HCV) co-infection. We hypothesize that the injection of opioids is partly responsible for the association between injection drug use and severe FI. Therefore, this analysis examines whether methadone maintenance treatment for opioid dependence is associated with a lower risk of severe Fl. Methods: We used biannual data from the Canadian Co-infection Cohort (N = 608, 2012-2015). Methadone treatment (exposure) was self-reported and severe FI (outcome) was measured using the Household Food Security Survey Module. To quantify the association between methadone treatment and severe FI, we estimated an average treatment effect on the treated (marginal risk difference [RD]) using propensity score matching. Results: Among participants, 25% experienced severe FI in the six months preceding the first time-point in the analytical sample and 5% concurrently reported receiving methadone treatment. Injection of opioids in the six months preceding the treatment and outcome measurements was much higher among those who received methadone treatment (39% vs. 12%). Among the treated participants, 97% had injected opioids in their lifetimes. After propensity score matching, the average risk of experiencing severe FI is 12.3 percentage-points lower among those receiving methadone treatment, compared to those who are not receiving treatment (marginal RD = -0.123, 95% CI = -0.230, 0.015). Conclusions: After adjustment for socioeconomic, sociodemographic, behavioural, and clinical confounders, methadone treatment is associated with a lower risk of severe FI. This finding suggests that methadone treatment may mitigate severe FI in this vulnerable subset of the HIV-positive population.