Retrospective, observational, multicentre study on an Italian population affected by chronic hepatitis C who failed to clear HCV-RNA after the combined therapy (PEG-IFN and ribavirin): NADIR study.

There is a lack of information on the characteristics of patients with chronic hepatitis C virus infection (HCV) who fail to respond to antiviral treatment. We studied HCV-positive subjects with chronic liver diseases treated with pegylated-interferon (PEG-IFN) and ribavirin (RBV) who failed to clear HCV in routine clinical practice. A total of 2150 consecutive adult patients treated with PEG-IFN plus RBV therapy in 46 Italian centres between 1 July 2004, and 30 June 2005, were studied. Of the 2150 patients, 923 (42.9%) (M/F 585/335, mean age 54.8 years) failed to achieve a serum HCV-RNA clearance. Of these 923 patients, 429 (46.5%) were nonresponders, 298 (32.3%) relapsers, 168 (18.2%) drop-outs for noncompliance or adverse events and 28 (3.0%) were lost during follow-up. Overall, 642 (70.6%) patients received adequate therapy (defined as more than 80% of the drug doses for >80% of the time). Genotypes 1-4 were observed in 76.9% of cases; genotypes 2-3 in 21.2% and mixed in 1.9%, respectively. Multiple logistic regression analysis identified genotypes 1 and 4 as the sole independent predictors of the likelihood of nonresponse to therapy compared with relapse (OR: 4.38; 95% CI = 2.28-8.4). Age older than 65 years was the sole independent factor associated with no adherence to therapy (OR: 2.22; 95% CI = 1.36-3.62). Patients who fail to respond to treatment are a nonhomogeneous population with different features, and the sole factor that discriminates nonresponse from relapse is the distribution of genotypes 1-4. Co-morbidities are unable to determine the type of treatment failure and inadequate adherence to therapy mostly affects patients older than 65 years of age.