Different impacts of common risk factors associated with thrombocytopenia in patients with hepatitis B virus and hepatitis C virus infection

Background: Thrombocytopenia is a common extrahepatic manifestation in chronic liver disease. However, there have been rare studies of impacts of risk for hepatitis C virus-associated thrombocytopenia (HCV-TP) and hepatitis B virus-associated thrombocytopenia (HBV-TP). The aim of this study is to evaluate different impacts of risk factors for HCV-TP and HBV-TP. Methods: We retrospectively collected 1803 HCV patients and 1652 HBV patients to examine the risk factors for time to moderate and severe thrombocytopenia (platelet counts <100 × 10⁹/L and <50 × 10⁹/L, respectively) by Cox proportional hazards models. Moreover, we prospectively enrolled 63 HCV-TP patients, 11 HBV-TP patients, and 27 HCV controls to detect specific antiplatelet antibodies by enzyme-linked immunosorbent assay and analyze their effects. Results: Prevalence of platelet <100 × 10⁹/L was 11.86% and 6.35% in HCV and HBV patients without cancer history, respectively. HCV-to-HBV incidence rate ratio for thrombocytopenia was 6.95. Initial thrombocytopenia was the most significant risk factor for HCV-TP and HBV-TP regardless of thrombocytopenia severity. Splenomegaly and cirrhosis were significant risk factors for moderate, but not severe HCV-TP. Hyperbilirubinemia was an important moderate and severe HBV-TP risk factor. Antiplatelet antibodies were correlated with HCV-TP severity, of which anti-glycoprotein IIb/IIIa antibody being associated with smaller spleen size. The antiplatelet autoantibody might contribute to thrombocytopenia either independently or with splenomegaly as the important risk in HCV-TP patients without advanced cirrhosis. Conclusion: HCV was associated with higher thrombocytopenia incidence than HBV. Thrombocytopenia risk factors varied with virus type and severity. Different management for HCV-TP and HBV-TP was suggested.