Rate of AIDS diseases or death in HIV-infected antiretroviral therapy-naive individuals with high CD4 cell count

OBJECTIVE: To assess the absolute rate of AIDS and death in antiretroviral therapy (ART)-naive patients with a high CD4 cell count. Such information would be helpful in the design of a trial investigating early initiation of ART. DESIGN: Analysis of data from an ongoing HIV cohort study. METHODS: The rate of (severe) AIDS or death and death alone was evaluated in ART-naive patients according to the current CD4 cell count, focusing on CD4 cell counts ≥ 350 cells/μl among patients in the UK CHIC Study. RESULTS: In a total of 30 313 person-years of follow-up, there were 1557 AIDS or death events. The rate of AIDS or death in persons with most recent CD4 cell count 350-499, 500-649 and > 650 cells/μl was 2.49, 1.54 and 0.96 per 100 person-years, respectively. The rate ratio for those with CD4 cell count 500-649 cells/μl compared with those with CD4 cell count ≥ 650 cells/μl was 1.55 [95% confidence interval (CI), 1.11-2.17; P = 0.01]. In a Poisson regression model based on person years with CD4 cell count ≥ 350 cells/μl, there was a strong effect of CD4 cell count on rate of AIDS or death (rate ratio, 0.84; 95% CI, 0.76-0.93; P = 0.001), independent of viral load and age. CONCLUSIONS: The trend of decreasing rate of AIDS and death with higher CD4 cell count is present throughout the CD4 cell count ≥ 350 cells/μl range in ART-naive people.