Anemia associated with antiviral therapy in chronic hepatitis C: Incidence, risk factors, and impact on treatment response

Background: One major side effect of combination antiviral therapy is the development of anemia, which is more severe among the Asian population. We conducted this large-scaled study to explore the incidence, risk factors, and impact on treatment response of anemia in chronic hepatitis C patients receiving combination antiviral therapy. Methods: Four hundred and sixty-six chronic hepatitis C patients were treated with interferon-α-2b (IFN-α-2b) three or five million units thrice weekly, or pegylated-IFN-α-2b 1-1.5μg/kg weekly plus ribavirin (1000-1200mg/day) for 24 weeks. Severe anemia was defined as hemoglobin concentration <10g/dl. Results: The mean decrease of hemoglobin was 3.9 ± 1.3g/dl. Thirty-nine percent of patients had developed severe anemia during therapy. Stepwise logistic regression analysis revealed that old age (≥ 50 years) (odds ratio [OR] =1.935, P = 0.001) and baseline hemoglobin level (≥ 14g/dl) (OR = 2.975, P <0.001) were significantly correlated with maximal decreases in hemoglobin. Using Cox's regression analysis, pretreatment platelet counts (< 150 000/ mm³) (OR = 1.821, P <0.001), old age (≥ 50 years) (OR = 1.789, P = 0.001), female gender (OR = 1.739, P <0.001), and low body weight (<65kg) (OR=1.493, P =0.027) were independent factors contributing to severe anemia. There was a significant linear correlation between the sustained virological response (SVR) rate and the time of severe anemia during therapy (r = 0.774, P = 0.003), especially among genotype 1 patients (r = 0.960, P < 0.001). Conclusion: Careful monitoring of hemoglobin level is necessary in patients who are old, female and have low body weight and platelet counts. Development of severe anemia was significantly correlated with the SVR.