Background: Adherence to antiretroviral therapy (ART) is essential to successful treatment of HIV infection. Two recent studies reported a negative correlation between marijuana use and adherence to ART. Some patients, however, report that smoking marijuana improves adherence to ART. This study therefore sought to identify which subgroups of patients may have differential adherence to ART in association with recent marijuana use.
Methods: Cross-sectional survey design within a public health care system for HIV/AIDS.
Results: With a 5% refusal rate, 252 patients completed the interview, 175 (69%) were on ART, and 168 (67%) provided ART adherence data. Forty-one subjects (24%), predominantly whites, used marijuana. In bivariate analysis, no association between ART adherence and marijuana use was found (odds ratio [OR] = 0.92, 95% CI = 0.4-1.9). Adherence was positively associated with undetectable plasma virus and negatively associated with alcohol and other illicit drug use. Examining subgroups of patients, among those with nausea, marijuana users were more likely to show an association with adherence than nonusers (OR = 3.3), while among those without nausea, marijuana use was lower associated with adherence (OR = 0.52, P for homogeneity 0.02). This relationship was confirmed in multivariate analyses controlling for the interactions between nausea and marijuana use, in which other illicit drug use remained a factor related to nonadherence.
Discussion: These data suggest that medicinal use of marijuana may facilitate, rather than impede, ART adherence for patients with nausea, in contrast to the use of other illicit substances, which were associated with lower rates of ART adherence. To demonstrate any causal relationship between marijuana and adherence would require a longitudinal or controlled study.