Risk Factors for Thrombocytopenia in HIV-Infected Persons in the Era of Potent Antiretroviral Therapy

Objective: Before potent antiretroviral therapy, thrombocytopenia was observed frequently. Little is known about risk factors for or severity and consequences of thrombocytopenia since establishment of highly effective therapy for HIV. Methods: We conducted a retrospective-snatched case-control study of HIV infected adult outpatients with and without thrombocytopenia to elucidate the contribution of HIV viremia, hepatitis C infection, and other potential risk factors for thrombocytopenia. Seventy-three cases with thrombocytopenia (platelet count <100 X 10(9)/L persistent for >3 months) were matched by age, sex, and first clinic visit with 73 nonthrombocytopenic controls. Risk factors and outcomes were assessed using conditional logistic regression. Results: Nadir platelet counts in cases were <= 50 X 10(9)/L in 58% and >= 30 X 10(9)/L in 38%. In multivariate modeling, HIV RNA >400 copies/ml, hepatitis C virus infection, and cirrhosis were significantly associated with thrombocytopenia with adjusted odds ratios of 5.3 [confidence interval (CI) 1.6-17.1, P = 0.006], 6.1 (CI 1.6-22.6, P = 0.007), and 24.0 (CI 1.7-338, P = 0.019), respectively. Thrombocytopenia was significantly associated with major bleeding events and nonbleeding-related death. Conclusions: Thrombocytopenia in the era of potent antiretroviral therapy is associated with hepatitis C virus infection, cirrhosis, and uncontrolled HIV replication, and serious complications including major bleeding and death.