CD4 ⁺ T cell count decreases by ethnicity among untreated patients with HIV infection in South Africa and Switzerland

Background: Estimates of the decrease in CD4 + cell counts in untreated patients with human immunodeficiency virus (HIV) infection are important for patient care and public health. We analyzed CD4 + cell count decreases in the Cape Town AIDS Cohort and the Swiss HIV Cohort Study. Methods: We used mixed-effects models and joint models that allowed for the correlation between CD4 + cell count decreases and survival and stratified analyses by the initial cell count (50-199, 200-349, 350-499, and 500-750 cells/μL). Results are presented as the mean decrease in CD4 + cell count with 95% confidence intervals (CIs) during the first year after the initial CD4 + cell count. Results: A total of 784 South African (629 nonwhite) and 2030 Swiss (218 nonwhite) patients with HIV infection contributed 13,388 CD4 + cell counts. Decreases in CD4 + cell count were steeper in white patients, patients with higher initial CD4 + cell counts, and older patients. Decreases ranged from a mean of 38 cells/μL (95% CI, 24-54 cells/μL) in nonwhite patients from the Swiss HIV Cohort Study 15-39 years of age with an initial CD4 + cell count of 200-349 cells/μL to a mean of 210 cells/μL (95% CI, 143-268 cells/μL) in white patients in the Cape Town AIDS Cohort-40 years of age with an initial CD4 + cell count of 500-750 cells/μL. Conclusions: Among both patients from Switzerland and patients from South Africa, CD4 + cell count decreases were greater in white patients with HIV infection than they were in nonwhite patients with HIV infection. © 2009 by the Infectious Diseases Society of America.