Introduction and aims: International guidelines and routine clinical practice express concerns about antiviral treatment in intravenous drug users (IDUs). We analysed the effect of IDU and/or substitution therapy on chronic hepatitis C (CHC) treatment adherence and response.
Patients and methods: Intravenous drug users with CHC were divided into three groups: (A) patients on a substitution programme; (B) active users; and (C) past IDUs. Patients were treated according to the standard of care and followed by a specialist team.
Results: A total of 175 patients (mean age 39.4±8.8) were included. One hundred and forty-four (65%) were adherent to therapy (completing treatment and 6 months of follow-up). Twenty-two patients (36%) discontinued because of side effects, 28 (46%) discontinued on their own and 11 (18%) completed treatment but did not present at follow-up. Of 142 patients with available treatment outcome, 99 (69.7%) achieved a sustained virological response (SVR), with no differences among the study groups. Patients with genotypes 2–3 and those who completed the treatment schedule had 2.78-fold (95% CI: 1.3–5.8) and 6.4-fold (95% CI: 2.6–15.6) higher probability of achieving SVR.
Conclusion: Active use of illicit drugs and/or drug substitution do not affect the treatment outcome in patients with CHC as long as they are closely followed and remain adherent to the treatment.