Unhealthy substance use may affect HIV disease progression indirectly via antiretroviral therapy (ART) adherence, or directly through biological mechanisms, such as immune function. This Canadian prospective cohort study examined whether non-injection substance use (crack cocaine, powdered cocaine, opioids, methamphetamine, alcohol, and cannabis) was associated with HIV-1 RNA viral load levels. Participants were 843 people living with HIV and illicit drug use who were assessed every 6 months with questionnaires and blood tests between 2005 and 2018.
- The cohort was 67% male with a median age of 43; 31% were homeless. The median baseline CD4 count was 340 (cells/µl), and median HIV viral load was 3.1 (log10 copies/ml).
- At baseline, 79% of participants had injection drug use, 79% had crack cocaine use, and 53% had alcohol use.
- Periods of crack cocaine use were associated with higher HIV viral load (while adjusting for age, sex, injection drug use, homelessness, CD4 count, and ART exposure), but there were no significant associations between the use of other substances—including powder cocaine—and HIV viral load.
- Participants received ART for a median of 180 days per 6-month period.
Comments: These findings regarding crack cocaine use reinforce prior studies, but the longitudinal design and availability of data on ART exposure from pharmacy records (as opposed to self-report) are strengths. Due to the high ART exposure, the authors suggest that data support a biological mechanism for crack cocaine leading to HIV disease progression. However, it is possible that crack cocaine use affected ART adherence in ways not captured by pharmacy dispensing records, especially since no association was found with powder cocaine. ART availability and adherence supports remain high priorities for people living with HIV and substance use.
Aaron D. Fox, MD
Reference: Liang J, Nosova E, Reddon H, et al. Longitudinal patterns of illicit drug use, antiretroviral therapy exposure and plasma HIV-1 RNA viral load among HIV-positive people who use illicit drugs. AIDS. 2020;34(9):1389–1396.