HCV treatment uptake in people who have injected drugs — observations in a large cohort that received addiction treatment 1970–1984

Abstract

Objectives. The aim of this study was to document antiviral treatment uptake among former or current people who inject drugs (PWID) with chronic hepatitis C and to explore a possible association between treatment and mortality. Material and methods. This is a longitudinal cohort study of PWID admitted for drug abuse treatment 1970–1984. The 245 hepatitis C virus (HCV) RNA-positive patients alive by the end of 1996 were followed 1997–2012 through linkage to several health registers. Treatment uptake was mainly documented by information on prescription of antiviral medication registered in the Norwegian Prescription Database from 2004. Cox regression, with a time-dependent covariate measuring end-of-treatment, was employed to evaluate mortality after treatment. Results. At the end of the follow-up, median time since HCV exposure was 36 years, and 19.2% (47/245) had been prescribed antiviral treatment for chronic HCV infection. No gender difference was observed. Among those alive at the end of the study period, 27.8% (44/158) had been treated. Relative hazard of death was 0.21 (95% confidence interval [CI] 0.07–0.68), comparing periods for patients after versus before or without treatment. Mortality rate after treatment was 0.8 per 100 person years (95% CI 0.3–2.4) compared to 2.8 (95% CI 2.2–3.5) in untreated patients and before treatment. The most important causes of death among the untreated were drug-related. Conclusions. Among PWID infected with HCV, approximately one-fourth of those still alive at a median of 36 years after exposure had received HCV treatment. Treatment was associated with increased survival, probably mainly due to selection bias.