HCV Treatment Outcomes in PWID: Impact of Addiction History on SVR12

People who inject drugs (PWIDs) experience high rates of hepatitis C virus (HCV) infection, primarily due to needle sharing and limited healthcare access, resulting in a disproportionate disease burden within this population. This prospective study evaluated treatment outcomes in 432 adult patients with chronic hepatitis C (CHC) treated with direct-acting antivirals (DAAs) at the University Clinical Center of Serbia. Patients were categorized into two groups based on a history of drug addiction: PWIDs (163, 37.7%) and non-PWIDs (269, 62.3%). The PWID group was further categorized into subpopulations of problematic PWIDs (39, 23.9%), ex-PWIDs (124, 76.1%), and PWIDs on OST (96, 58.9%). The PWID group demonstrated significantly lower treatment adherence, with an intention-to-treat (ITT) rate of 82.8%, compared to 96.3% in the control group (<i>p</i> < 0.001). In contrast, no significant differences were observed in per-protocol (PP) outcomes between the two groups. Additionally, PWIDs were significantly younger (<i>p</i> < 0.001) and had higher rates of psychiatric disorders (<i>p</i> < 0.001), alcohol abuse (<i>p</i> < 0.001), and HCV genotype 1a (<i>p</i> < 0.001). Advanced fibrosis was predictor of PP treatment failure among PWIDs, while mood disorders and alcohol use disorder were associated with interruptions before the scheduled completion time. For non-PWIDs, older age and advanced fibrosis emerged as key predictors of PP treatment failure. The loss to follow-up was most commonly observed in the problematic PWID subgroup (<i>p</i> = 0.001). These findings highlight the importance of addressing barriers in PWIDs through integrated care strategies that concurrently manage addiction and HCV.