BackgroundHaematological adverse events related to pegylated interferon (PEG-IFN) and ribavirin (RBV) therapy could affect the patients’ quality of life; however, the risk factors for severe haematological toxicity associated with this therapy in patients coinfected with hepatitis C virus (HCV) and HIV are unclear. The objective of this study was to identify predictors of severe haematological toxicity among HIV-HCV-coinfected patients treated with PEG-IFN plus RBV.MethodsThis retrospective multicentric study included 237 HIV-HCV-coinfected patients on PEG-IFN plus RBV. Predictors of severe anaemia, neutropenia, thrombocytopenia and overall haematological toxicity were analyzed.ResultsEighty (34%) individuals showed an episode of severe haematological toxicity. Severe anaemia, neutropenia and thrombocytopenia occurred in 32 (13%), 42 (18%) and 26 (11%) patients, respectively. In the multivariate analysis, zidovudine use (adjusted odds ratio [AOR] 3.3; 95% confidence interval [CI] 1.6–10; P=0.001), baseline body weight <65 kg (AOR 2.5; 95% CI 1.1–5; P=0.024), cirrhosis (AOR 5; 95% CI 1.6–16.6; P=0.006), PEG-IFN-α2a (AOR 2.7; 95% CI 1.1–6.6; P=0.029) and pretreatment haemoglobin level <14 g/dl (AOR 2.7; 95% CI 1.3–5.5; P=0.005) were associated with any kind of severe haematological toxicity. Likewise, haemoglobin level <13 g/dl, neutrophil counts <2,500 cells/mm³and platelet counts <175,000 cells/mm³were independent predictors of severe anaemia, neutropenia and thrombocytopenia, respectively.ConclusionsZidovudine treatment, cirrhosis, baseline low body weight, use of PEG-IFN-α2a, and baseline haemoglobin level <14 g/dl are predictors of overall severe haematological toxicity secondary to PEG-IFN plus RBV in HIV-infected individuals. Low pretreatment levels of each haematological series predict a significant decrease of their values during therapy.