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

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.

Retrospective cohort study.

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.

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.

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.