Treatment Adherence to Oral Direct‐Acting Antiviral Agents in Hepatitis C Infection

BACKGROUND: Optimal adherence to second-generation direct-acting antiviral agents (DAAs) is crucial for preventing disease progression and reducing treatment resistance in patients with Hepatitis C virus (HCV). Therefore, we examined DAA adherence and its predictors in patients with HCV. STUDY DESIGN: Retrospective cohort study. METHODS: The study cohort included adult patients with HCV in the Merative MarketScan databases from 2017 to 2019. Incident DAA users were selected with a 12-month baseline continuous enrollment. Adherence was assessed during the 8- to 24-week follow-up period, as per guidelines, using two adherence metrics: the proportion of days covered (PDC ≥ 80%) and the completion of therapy (≤ 14-day gap). Predictors of non-adherence were assessed by multivariable logistic regression based on the Andersen Behavioral Model. Sensitivity analysis was conducted at PDC ≥ 70% and ≥ 90%, and a gap of ≤ 21 days. RESULTS: Among 3412 incident DAA users, 84.79% of patients were adherent (PDC ≥ 80%), and 84.23% of patients completed the treatment without a significant gap (≥ 14 days). Several predictors were associated with non-adherence and were consistent for both adherence metrics. Older age (55-64 years, adjusted odds ratio [aOR]: 0.50, 95% Confidence Interval [CI]: 0.35-0.70) and middle-aged adults (45-54 years, aOR: 0.53, 95% CI: 0.37-0.75) were less likely to be non-adherent. High monthly out-of-pocket (OOP) costs (≥ $400) increased the risk of non-adherence (aOR: 1.25, 95% CI: 1.02-1.54). Patients with cirrhosis (compensated: aOR: 3.85, 95% CI: 2.99-4.94; decompensated: aOR: 3.02, 95% CI: 1.95-4.70), HIV infection (aOR: 1.83, 95% CI: 1.06-3.18), and substance use disorder (aOR: 1.38, 95% CI: 1.01-1.89) were found to have higher odds of being non-adherent. Patients who were prescribed the velpatasvir/sofosbuvir regimen were less likely to be non-adherent (aOR: 0.78, 95% CI: 0.62-0.99). Sensitivity analysis yields similar findings. CONCLUSIONS: Overall adherence to DAA therapy was high in HCV; however, several clinical and non-clinical factors were associated with non-adherence. Findings from this study can inform the development of targeted interventions to optimize DAA adherence in HCV.