Strong association of hepatitis C virus (HCV) infection and thrombocytopenia: Implications from a survey of a community with hyperendemic HCV infection

Background. The role of hepatitis C virus (HCV) infection in thrombocytopenia (defined as a platelet count of < 100,000 platelets/mL) is unknown. Our aim was to study the association between HCV infection and thrombocytopenia in a community where hepatitis B virus (HBV) and HCV infections are hyperendemic. Methods. A community-wide survey of subjects greater than or equal to 40 years old who had undergone a preventive health examination between April 1997 and July 2000 in A-Lein Township, Kaohsiung County, Taiwan. Serum blood platelet counts and HBV surface antigen (HBsAg) and antibody to HCV (anti-HCV) levels were measured. Abdominal sonography was performed on viral hepatitis-positive participants. Results. Among the 1690 subjects, 70% were seronegative, 17.4% were anti-HCV positive, 9.2% were HBsAg positive, and 3.4% were coinfected with HCV and HBV. The mean platelet count in subjects with anti-HCV (180,000 platelets/mL) was lower than in those with HBsAg (201,000 platelets/mL) and in those without anti-HCV and HBsAg (234,000 platelets/mL) (P < .001). The prevalence of thrombocytopenia was 1.3% among seronegative subjects, 1.9% among HBsAg-positive subjects, 5.2% among coinfected subjects, and 10.2% among anti-HCV positive subjects. Multiple logistic regression analysis revealed that anti-HCV positivity (odds ratio, 6.0; 95% confidence interval, 3.2 - 11.2), an alanine aminotransferase level of greater than or equal to 40 U/L, and age of greater than or equal to 65 years were significantly associated with thrombocytopenia. The prevalence of thrombocytopenia among anti-HCV - positive subjects increased as the severity of liver disease increased, but, in HBsAg-positive subjects, thrombocytopenia presented only in those with advanced liver disease. Conclusions. HCV infection is strongly associated with thrombocytopenia, which is correlated with hepatocellular damage and hepatic fibrosis. It is advisable to further check the hepatic condition of the patient, especially for HCV infection, if thrombocytopenia is present.