Relationship of CD4 lymphocyte counts to survival in a cohort of hemophiliacs infected with HIV

Although CD4 positive lymphocyte counts are important predictors of clinical events in persons infected with human immunodeficiency virus (HIV), little is known about their predictive value for survival. We analyzed CD4 counts obtained regularly since 1983 with regard to survival in a multi-center cohort study of 921 HIV-infected hemophiliacs of whom 177 have died. Dates of seroconversion were determined from stored serum samples. Cumulative mortality and actuarial survival rates were calculated from the first time the mean of two consecutive CD4 counts decreased from levels of >500 to 200-499,100-199,50-99, and <50 cells/μ l. The death rate per 100 patient years of observation was 0.87 (95% CI 0.27,1.47) for those with CD4 counts of >500 cells/μ l and increased progressively to 26.23 (95% CI 21.29, 31.17) for those with CD4 counts of <50/μ l. HIV-related deaths occurred in 50 of 58 who died with CD4 counts of <300/μ l compared to 0 of 6 who died with CD4 counts of >500/μ l. The median CD4 count most proximal to death was 39.5 (range, 1-945). The 10-year actuarial estimate of survival from seroconversion was 77.3 ± 2% for 546 persons who seroconverted at age ≥18 years compared to 90.5 ± 2% for 375 persons who seroconverted at age <18. Survival decreased at each CD4 level to a median of 27 months at CD4 counts of <50/μ l. At each CD4 level, younger patients survived longer than older patients. In this cohort, death was 32 times more frequent with very low CD4 counts (<50 cells/μ l) compared to high CD4 counts (<500 cells/μ l). However, among those with very low CD4 counts, survival was much longer than had previously been described and younger age at seroconversion was a positive prognostic factor at all CD4 levels.