Abstract
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.