Prevalence, severity, and duration of thrombocytopenia among HIV patients in the era of highly active antiretroviral therapy.

Thrombocytopenia is a clinically relevant outcome in HIV. However, the epidemiology of this condition, including frequency, severity, and duration, has not been well-characterized in the era of highly active antiretroviral therapy (HAART). In this study, we describe the epidemiology of thrombocytopenia using two methods. We conducted a systematic review of the literature published between 1997 and 2009 to characterize the frequency of thrombocytopenia in different populations in the HAART era. Secondly, we examined the frequency, severity, and duration of thrombocytopenia among HIV patients in the Collaborations in HIV Outcomes Research/US (CHORUS) Cohort from 1997 to 2006 and among HIV patients participating in GlaxoSmithKline HIV Clinical Trials between 1996 and 2004. Prevalence estimates of thrombocytopenia (<150 000 platelets/µl) in the literature varied greatly but were generally above 10%. The thrombocytopenia prevalence estimates in the CHORUS Cohort and the HIV Clinical Trials were both 14%. In the CHORUS Cohort, the platelet count was ≤50 000/µl among 3.1% and ≤30 000/µl among 1.7%; in the HIV clinical trials database, the platelet count was ≤50 000/µl among 1.3% and ≤30 000/µl among 0.67%. Duration of severe thrombocytopenia varied greatly, with the medium duration to ≥75 000 platelets/µl taking 147 days in the CHORUS Cohort and 33 days in the HIV clinical trials database. Among 111 patients with severe thrombocytopenia in the CHORUS Cohort, 23% never achieved a higher platelet count over follow-up. In conclusion, while the prevalence of severe thrombocytopenia was low, it occurred at levels associated with bleeding and was persistent among a small proportion of patients despite receipt of HAART.