An investigation of the possible interaction between the use of Vitamin C and highly active antiretroviral therapy (HAART) adherence and effectiveness in treated HIV+ women☆

Summary Objectives Our goal in this study was to examine how Vitamin C interacts with antiretroviral therapy in individuals with HIV. We specifically evaluated how Vitamin C impacts highly active antiretroviral therapy (HAART) adherence and HAART effectiveness as adjudicated by HIV viral loads and CD4 cell counts. Women served as their own controls, comparing periods of Vitamin C usage with periods of non-usage. Design An intra-individual, cross-sectional comparative study ‘nested' in the WIHS observational cohort study. Subjects Women in the Women's Interagency HIV Study (WIHS). Outcome measures Adherence, CD4 count and viral load. Results Our study population was drawn from 2813 HIV+ participants who contributed 44,588 visits in WIHS from October, 1994 to April, 2009. Among them, there were 1122 Vitamin C users with 4954 total visits where use was reported. In the multivariate model adjusting for age, education, race, income, drug use, Vitamin C use order and depression score, there was a 44% increase in the odds of ≥95% HAART adherence among participants during their period of Vitamin C use compared to when they were not using Vitamin C (OR=1.44; 95% CI=1.1–1.9; P -value=0.0179). There was an association with Vitamin C usage and CD4 counts on viral loads. Conclusion Vitamin C usage appears to be associated with improved adherence. Future Vitamin C studies should target specific HAART drugs, and prospective clinical outcomes.