Intravenous Drug Users Can Achieve a High Sustained Virological Response Rate: experience From Croatian Reference Center for Viral Hepatitis

Hepatitis C virus (HCV) is one of the major infectious disease agents among injecting drug users (IVDUs). However, most of the IVDUs are not still treated. To examine the treatment course, adherence, tolerability and safety profiles and SVR rates in IVDUs compared to non-IVDUs. Demographic and clinical data were collected from medical records of 345 adult patients diagnosed with chronic hepatitis C (CHC) who were treated with a PEG-IFN-α and ribavirin in Croatian Reference Center for Viral Hepatitis in Zagreb between January 2003 and January 2010. Efficacy, safety and tolerability treatment profiles were analyzed in IVDUs vs. non-IVDUs. Positive predictors for treatment outcome were evaluated by univariate and multivariate logistic regression. A total of 106 (30.46%) IVDUs were identified. The IVDUs were mainly male (81.13% vs. 52.30%, P = 0.0001), young (mean ± SD age: 32.46 ± 5.33 y vs. 46.12 ± 11.48 y, P = 0.0001), had lower fibrosis and HAI score (measured by ISHAK) and shorter duration of infection (mean ± SD: 8.98 ± 5.87 vs. 16.79 ± 8.99 y, P = 0.0001) compared to non-IVDU group. In IVDUs, genotype 1a (24.52%) and 3a (38.68%) were predominant. There were no differences in completion rate between the two studied groups. IVDUs achieved a significantly higher rate of overall SVR (70.75% vs. 51.04%, P < 0.0009) and in genotypes 1 and 4 (65.08% vs. 48.73%, P = 0.0294) vs. non-IVDUs. Treatment discontinuation rates due to side-effects were not significantly different in IVDUs and non-IVDUs (2.83% vs. 7.11%, P = 0.1390). IVDU group had a higher rate of lost to follow-up (13.21% vs. 4.60%, P = 0.0071). There were no statistically significant differences in SVR rate between IVDUs with, or without substitution therapy (55.55% vs. 74.62%, P = 0.0866). Independent predictors of SVR were age < 40 years and genotypes 2 and 3. Type of PEG-IFN-α used was not associated with SVR. Treatment of CHC in IVDUs should strongly be encouraged as they have positive predictors for achieving SVR such as younger age, shorter duration of infection, and consequently favorable histological stage of the disease, and good adherence to treatment. There is no difference in safety and tolerability profiles of treatment in IVDUs compared to patients with no history of drug abuse.