Thrombocytopenia in HIV-infected and uninfected hemophiliacs. Multicenter Hemophilia Cohort study.

To determine the incidence and prognostic significance of thrombocytopenia among hemophiliacs, we analyzed clinical and hematologic data from the Multicenter Hemophilia Cohort study. Nineteen percent of HIV-infected subjects had thrombocytopenia (platelet count of <100,000/mm3) noted at least once, compared to 3% of HIV-uninfected subjects. For HIV-infected subjects, the prevalence of thrombocytopenia rose in the first 5 years after seroconversion and was twice as common in subjects age >35 years compared to younger subjects. The risk increased after an AIDS-defining illness, particularly among older subjects, nearly one-half of whom had thrombocytopenia within 1 year after AIDS. When adjusted for age and CD4-positive lymphocyte counts, thrombocytopenia was associated with an increased risk of death [relative risk (RR) 1.7, 95%CI = 1.2-2.3] but with little change in the risk of progression to AIDS (RR = 1.2, 95%CI = 0.8-1.7). Treatment with zidovudine was associated with a decreased risk of thrombocytopenia (RR = 0.5, 95%CI = 0.3-0.7). Although 59 HIV-infected subjects died of hemorrhage, only 11 (19%) of the 59 had a reported platelet count of <50,000/mm3, and only 2 (3%) of the deaths were temporally associated with thrombocytopenia. Thus, the risk of death was increased for thrombocytopenic HIV-infected hemophiliacs but this was not explained by an increased risk of developing AIDS and was rarely associated with death from bleeding.