Baseline Factors associated with Haematological Toxicity that Leads to a Dosage Reduction of Pegylated Interferon-a2a and Ribavirin in HIV- and HCV-Coinfected Patients on HCV Antiviral Therapy

Objective To assess the baseline factors associated with haematological toxicity that lead to ribavirin or pegylated interferon (peginterferon) dosage reductions in hepatitis C and human immunodeficiency virus (HCV/HIV)-coinfected patients.Design Multicentre, prospective, observational study.Setting Eleven hospitals in Spain during the period 2002–2003.Subjects and methods One-hundred and forty-two HIV/HCV-coinfected patients received peginterferon-a2a plus ribavirin. Baseline characteristics and haematological parameters were recorded at baseline, week 4, 8, 12, 24 and 48. Cox's regression model was used to study the factors associated with the appearance of a haemoglobin level below 10g/dl (haemoglobin-endpoint), a neutrophil count below 750/mm3(neutrophil-endpoint) and a platelet count below 50,000/mm3(platelet-endpoint).Results Nineteen patients (13.4%) reached the haemoglobin-endpoint, 22.5% the neutrophil-endpoint and 7% the platelet-endpoint. Mean time of follow-up was 8 months (±3.5). A baseline haemoglobin level below 14g/dl [hazard ratio (HR): 3.65; 95% confidence interval (CI): 1.46–9.06] and treatment with zidovudine (HR: 3.25; 95% CI: 1.31–8.11) were the independent factors associated with the appearance of the haemoglobin-endpoint. A baseline neutrophil below 2050/mm3(HR: 3.59; 95% CI: 1.77–7.28) and baseline weight <60 kg (HR: 2.21; 95% CI: 1.04–4.56) were independently associated with the appearance of the neutrophil-endpoint. Baseline platelet count (x1000/mm3decrease) (HR: 1.074; 95% CI: 1.04-1.11) was independently associated with the appearance of the platelet-endpoint.Conclusions Baseline factors allow the identification of a subset of HIV/HCV-coinfected patients who are prone to experience haematological toxicity during HCV antiviral therapy.