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-matched 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 <or=50 x 10(9)/L in 58% and <or=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.