926 Gender is Associated with Virologic Rebound and CD4 Cell Increases in Those Initiating Highly Active Antiretroviral Therapy: An Observational Study T. Forte*1,2, A. M. Bayoumi1, P. Millson 1, P. Villeneuve 3, R. S. Remis1, C. Major2 1Univ of Toronto, Canada; 2Ontario HIV Treatment Network, Toronto, Canada; and 3Univ of Ottawa, Canada
Background: To investigate virologic and immunologic responses to highly active antiretroviral therapy (HAART) among men and women .
Methods: We studied participants enrolled in the HIV Ontario Observational Database, a voluntary longitudinal cohort. We obtained supplementary viral load and CD4 data from Ontario’s Public Health Laboratory. We included participants starting their first HAART regimen who had CD4 and viral load results before and after HAART initiation.
Results: Of 470 eligible participants, 60 (12.8%) were women. Compared to men, women had higher CD4 counts (median 315 vs 272 cells/µL, p = 0.05) and lower viral loads (median 16,887 vs 33,185 copies/mL, p < 0.05) prior to initiating HAART. No significant gender difference was observed in time to achieve an undetectable viral load (median time of 3.1 vs 2.7 months (mos), p = 0.68). After adjusting for age, race, education, injection drug use, region of care, months since testing HIV positive, previous antiretroviral experience, frequency of testing, CD4 count and viral load before HAART initiation, and inclusion of protease inhibitors in a HAART regimen, we still observed no difference (relative hazard: 1.04 comparing women to men, 95% confidence interval: 0.75, 1.45). Women were significantly more likely to experience virologic rebound (median time 17.2 mos for women and 51.8 mos for men, p = 0.001). After adjusting for the same covariates, we still found men to have a more durable response (relative hazard: 0.56 comparing women to men, 95% confidence interval: 0.35, 0.89). No gender difference was found in time to achieve a 20% or greater increase in CD4 cells (median time 7.7 vs 7.6 mos, p = 0.93). However, the absolute increase in CD4 counts after HAART initiation was greater in women and persisted after adjusting for the same potential confounders (mean 470.9 vs 288.5 cells/µL; p = 0.010).
Conclusions: Women in our cohort had less durable virologic responses to HAART and experienced greater CD4 cell increases.
