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/mL). 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/mL (95% CI, 24–54 cells/mL) in nonwhite patients from the Swiss HIV Cohort Study 15–39 years of age with an initial CD4+ cell count of 200–349 cells/mL to a mean of 210 cells/mL (95% CI, 143–268 cells/mL) in white patients in the Cape Town AIDS Cohort 40 years of age with an initial CD4+ cell count of 500–750 cells/mL. 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.