Factors Linked to Severe Thrombocytopenia During Antiviral Therapy in Patients with Chronic Hepatitis C and Pretreatment Low Platelet Counts

Background: Baseline low platelet count (< 150,000/μL) increases the risk of on-treatment severe thrombocytopenia (platelet count < 50,000/μL) in patients with chronic hepatitis C (CHC) undergoing antiviral therapy, which may interrupt treatment. The purpose of this study was to identify risk factors for severe thrombocytopenia during treatment for CHC in patients with baseline thrombocytopenia.

Methods: Medical records were reviewed for 125 patients with CHC treated with antiviral therapy according to the standard of care, with regular follow-up examinations. Early platelet decline was defined as platelet decrease during the first 2 weeks of therapy.

Results: Severe thrombocytopenia developed in 12.8% of patients with baseline thrombocytopenia, and predicted a higher therapeutic dropout rate. Multivariate analysis revealed baseline platelet count < 100,000/μL and rapid early platelet decline (> 30% decline in the first 2 weeks) were significantly associated with severe thrombocytopenia (P < 0.001 and 0.003, odds ratios, 179.22 and 45.74, respectively). In these patients, baseline PLT ≥ 100,000/μL and lack of rapid early platelet decline predicted absence of severe thrombocytopenia (negative predictive values were 95.1% and 96.6%, respectively). In contrast, baseline platelet count < 100,000/μL combined with rapid early platelet decline predicted severe thrombocytopenia (positive predictive value was 100%).

Conclusions: For patients with CHC on antiviral therapy, baseline platelet counts < 100,000/μL and rapid early platelet decline can identify patients at high risk of developing on-treatment severe thrombocytopenia.