• anaemia;
  • hepatitis C;
  • HIV;
  • pegylated interferon;
  • ribavirin

Summary.  Ribavirin (RBV) exposure is important for maximizing the response to chronic hepatitis C virus (HCV) therapy. However, RBV-associated haemolytic anaemia may force dose reductions or even treatment discontinuation. The use of zidovudine might further increases the risk of anaemia in HCV/HIV-coinfected patients. The predictors of anaemia were examined in PRESCO, a large trial conducted in HIV/HCV-coinfected patients treated with pegylated interferon alpha-2a 180 μg/week plus RBV 1000–1200 mg/day. Measurements included maximal decrease in haemoglobin (Hb) throughout treatment, drops in Hb to <10 (moderate) or to <8.5 g/dL (severe), and premature RBV discontinuation because of anaemia. Finally, the impact of anaemia on sustained virological response (SVR) was assessed. Moderate or severe anaemia occurred, respectively, in 51 (13%) and 13 (3.3%) of 389 patients included in the study. Lower baseline Hb [RR: 0.14 (95% CI 0.07–0.27); P < 0.0001] and greater Hb drops during the first 4 weeks of therapy [RR: 4.74 (95% CI 2.95–7.60); P < 0.0001] were independent predictors of moderate anaemia at any time point in the multivariate analysis. Mean drops in Hb from baseline to week 4 were significantly greater in patients receiving zidovudine compared with other drugs (−3.09 vs−2.3 g/dL; P < 0.001). Lower baseline Hb [RR: 0.33 (95% CI 0.11–0.95); P = 0.04] and maximal Hb drops during treatment [RR: 2.48 (95% CI 1.33–4.59); P = 0.004] predicted treatment discontinuation because of anaemia. However, maximal Hb drops, development of moderate–severe anaemia and RBV dose reductions were comparable among patients who achieved SVR and those who did not. Lower baseline Hb predicts maximal drops in Hb and development of anaemia in HIV/HCV-coinfected patients treated with pegylated interferon plus RBV. The use of zidovudine is associated with greater Hb declines at week 4. However, severe anaemia is relatively infrequent and seems not to have much impact on SVR. Given the availability of alternative antiretroviral drugs, it is advised to avoid zidovudine while receiving anti-HCV treatment.