Crack cocaine use frequency is associated with HIV disease severity independent of antiretroviral therapy exposure: a prospective cohort study

Background: Prior evidence suggests that plasma HIV viral load is elevated during periods of crack cocaine use independent of antiretroviral therapy (ART) exposure. We sought to evaluate the effect of crack cocaine use frequency on HIV disease severity among HIV-positive people who use unregulated drugs (PWUD). Methods: We analyzed data from the ACCESS study, an open prospective cohort of HIV-positive PWUD including comprehensive HIV clinical monitoring in a setting with no-cost healthcare, including ART. Multivariable generalized linear mixed-effects models were used to estimate the independent effect of time-updated crack cocaine use frequency on HIV disease severity, adjusting for ART exposure and relevant confounders. HIV disease severity was measured using the Veterans Aging Cohort Study (VACS) Index, which is a validated prognostic index. Findings: Between 2005 and 2018, 806 individuals were recruited and contributed 8,537 observations. At baseline, the frequencies of crack cocaine use in the previous 180 days were: none (187, 23%), less than weekly (150, 19%), weekly (229, 28%), and daily or greater (240, 30%). In multivariable models adjusted for ART exposure and other confounders, daily or greater frequency of crack cocaine use was significantly associated with higher VACS Index scores (β = 0.9, 95% confidence interval: 0.2, 1.6) as compared to none. Interpretation: Daily or greater frequency of crack cocaine use may exacerbate HIV disease severity among HIV-positive PWUD. Although the observed effect was small, it was also independent of ART exposure. As this finding has been supported by previous evidence, the observed difference may reflect an underlying biological mechanism or other factors linked with crack cocaine use although further investigation is warranted. Funding Information: US National Institutes of Health. Declaration of Interests: We declare no competing interests. Ethics Approval Statement: The ACCESS study was approved by the University of British Columbia/Providence Healthcare Research Ethics Board.