Factors influencing increases in CD4 cell counts of HIV-positive persons receiving long-term highly active antiretroviral therapy.
BACKGROUND: Highly active antiretroviral therapy (HAART) results in an improvement in immunologic function. We sought to investigate the factors associated with increases in CD4 cell count among human immunodeficiency virus (HIV)-positive antiretroviral-naive patients starting HAART. METHODS: Five hundred ninety-six subjects were followed for a median of 2.5 years (interquartile range, 1.0-4.0 years). Factors associated with changes in CD4 cell counts in the first 3 months of HAART and from 3 months onwards were analyzed. RESULTS: After 6, 12, and 24 months of HAART, the median increases in CD4 cell counts were 114, 181, and 248 cells/mm3, respectively; 84%, 84%, and 80% of subjects had a virus load of <400 copies/mL during the same periods. White ethnicity, higher pre-HAART virus load, and lower pre-HAART CD4 and CD8 cell counts were associated with greater increases in CD4 cell counts during the first 3 months of HAART. From 3 months onward, a greater cumulative proportion of time spent with virus load <400 copies/mL was associated with a more favorable change in CD4 cell count (an average increase of 5.2 cells/mm3/year [95% confidence interval [CI], 3.8-6.7 cells/mm3/year] for each extra 10% cumulative time spent with a virus load <400 copies/mL) (P<.0001). For every 100 cells/mm3 higher in baseline CD4 cell count, the increase was 6 cells/mm3/year less (95% CI, 2-11 cells/mm3/year) (P=.02). Sex, risk group, age, and HAART regimen were not associated with increases in CD4 cell counts. CONCLUSIONS: These findings emphasize the importance of maintaining virological suppression and suggest other factors that influence long-term CD4 cell response.