One in four persons living with HIV is coinfected with chronic hepatitis C virus (HCV). Biological interaction between HIV and HCV, and behaviors such as decreased antiretroviral therapy (ART) adherence and drug use, may negatively impact HIV treatment outcomes among persons with HIV/HCV-coinfection. Yet, previous research assessing the effect of HCV on HIV treatment outcomes produced inconsistent results. Evidence regarding the effect of HCV on HIV treatment outcomes is also lacking among women. Therefore, we estimated the effect of chronic HCV on HIV suppression and the effects of chronic HCV and depression on AIDS diagnosis or death among women who initiated ART while enrolled in the Women's Interagency HIV Study (WIHS).

We estimated the effect of chronic HCV on HIV suppression by comparing the proportion of study visits with detectable HIV RNA between women with and without chronic HCV. Among 441 women who initiated ART in 2000 or after, 114 (26%) had chronic HCV. Overall, the risk of having a visit with detectable HIV RNA was similar among women with and without chronic HCV (risk ratio (RR) 1.19; 95% confidence interval (CI) 0.72, 1.95)). However, six months after ART initiation, the proportion of visits with detectable HIV RNA among women with chronic HCV was 1.88 (95% CI 1.41, 2.51) times that among women without chronic HCV, at two years the ratio was 1.60 (95% CI 1.17, 2.19), and by six years there was no difference (RR 1.03; 95% CI 0.60, 1.79).

When assessing the effects of chronic HCV and depression on AIDS diagnosis or death among 957 women who initiated ART between 1995 and 2015, 200 women (21%) had chronic HCV. The incidence rates of AIDS diagnosis or death were 7.12 and 3.80 per 100 person-years for women with and without chronic HCV, respectively. Compared to women without chronic HCV and depression, the hazard ratio (HR) for AIDS diagnosis or death was 2.19 (95% CI 1.56, 3.07) for HCV-uninfected women with depression, 1.65 (95% CI 0.90, 3.01) for HCV-infected women without depression, and 3.02 (95% CI 1.49, 6.15) for HCV-infected women with depression.