Factors associated with initiation of antiretroviral therapy among HIV-positive people who use injection drugs in a Canadian setting.

OBJECTIVE: To identify behavioral, social, and structural factors associated with time from HIV seroconversion to antiretroviral therapy (ART) initiation among people who use injection drugs (PWID). DESIGN: Two complementary prospective cohorts of PWID linked to comprehensive ART dispensation records in a setting of universal no-cost HIV/AIDS treatment and care. METHODS: Multivariable extended Cox models of time to ART initiation among baseline HIV-seronegative PWID who seroconverted after recruitment adjusted with a time-updated measure of clinical eligibility for ART. RESULTS: We included 133 individuals of whom 98 (74%) initiated ART during follow-up at a rate of 12.4 per 100 person-years. In a multivariable model adjusted for ART eligibility, methadone maintenance therapy [adjusted hazard ratio (AHR) = 2.37, 95% confidence interval (95% CI): 1.56-3.60] and a more recent calendar year of observation (AHR = 1.06, 95% CI: 1.00-1.12) were associated with more rapid ART initiation, whereas informal income generation (AHR = 0.51, 95% CI: 0.32-0.79) and incarceration (AHR = 0.52, 95% CI: 0.28-0.97) were negatively associated with ART initiation. CONCLUSION: In this sample of community-recruited HIV-positive PWID with well defined dates of HIV seroconversion, we found that two measures related to the criminalization of illicit drug use each independently delayed ART initiation regardless of clinical eligibility. Engagement in methadone promoted ART initiation. Programs to scale-up HIV treatment among PWID should consider decreased criminalization of PWID and increased access to opioid substitution therapy to optimize the impact of ART on HIV/AIDS-associated morbidity, mortality, and HIV transmission.

Factors linked to transitions in adherence to antiretroviral therapy among HIV-infected illicit drug users in a Canadian setting.

HIV-positive people who use illicit drugs typically achieve lower levels of adherence to antiretroviral therapy and experience higher rates of sub-optimal HIV/AIDS treatment outcomes. Given the dearth of longitudinal research into ART adherence dynamics, we sought to identify factors associated with transitioning into and out of optimal adherence to ART in a longitudinal study of HIV-infected people who use illicit drugs (PWUD) in a setting of universal no-cost HIV/AIDS treatment. Using data from a prospective cohort of community-recruited HIV-positive illicit drug users confidentially linked to comprehensive HIV/AIDS treatment records, we estimated longitudinal factors associated with losing or gaining ≥95% adherence in the previous six months using two generalized linear mixed-effects models. Among 703 HIV-infected ART-exposed PWUD, becoming non-adherent was associated with periods of homelessness (adjusted odds ratio [AOR] = 2.52, 95% confidence interval [95% CI]: 1.56-4.07), active injection drug use (AOR = 1.25, 95% CI: 1.01-1.56) and incarceration (AOR = 1.54, 95% CI: 1.10-2.17). Periods of sex work (AOR = 0.51, 95% CI: 0.34-0.75) and injection drug use (AOR = 0.62, 95% CI: 0.50-0.77) were barriers to becoming optimally adherent. Methadone maintenance therapy was associated with becoming optimally adherent (AOR = 1.87, 95% CI: 1.50-2.33) and was protective against becoming non-adherent (AOR = 0.52, 95% CI: 0.41-0.65). In conclusion, we identified several behavioural, social and structural factors that shape adherence patterns among PWUD. Our findings highlight the need to consider these contextual factors in interventions that support the effective delivery of ART to this population.