OBJECTIVES : Patients with substance use disorders (SUD) and chronic hepatitis C virus infection (HCV) have limited access to direct-acting antivirals (DAAs). The effects of DAAs on real-world health care utilization and costs among these patients is unknown. We aim to compare changes in medical service utilization and costs related to liver, SUD, and all-cause morbidity in patients with SUD and HCV treated with DAAs (DAA group) versus those not treated with DAAs (non-DAA group).

METHODS : We conducted a retrospective cohort study using MarketScan data (2012-2018) for newly diagnosed HCV-infected adults with SUD. After applying the stabilized inverse probability of treatment weights, we used difference-in-differences analyses, stratified by cirrhosis status, to determine the adjusted ratio of rate ratio (RRR) to assess the difference in the changes from the pre- to the post-treatment period between the DAA and non-DAA groups. Zero-inflated negative binomial regression and two-part models were used.

RESULTS : 6266 patients with SUD and HCV were identified. For patients with cirrhosis (n=607), a greater decrease in liver-related costs after DAAs was observed for the DAA group compared to the non-DAA group (RRR=0.37; 95% confidence interval (CI)=0.19-0.73). The DAA group was associated with a significant decrease in all-cause office visits (RRR=0.70; 95% CI=0.60-0.81) compared to non-DAA group. There was no difference in the changes after DAAs in SUD-related visits/costs, or all-cause costs between groups. For patients without cirrhosis (n=5659), a similar trend was observed, except for the DAA group that experienced a significant decrease in SUD-related emergency department (ED) visits (RRR=0.54; 95%CI=0.38-0.77), and SUD-related long-term care visits (RRR=0.30; 95%CI=0.13-0.73).

CONCLUSIONS : DAAs are associated with a significant decrease in SUD-related ED and long-term care visits, and liver-related costs without increasing all-cause costs among patients with SUD and HCV, suggesting the benefits of DAAs extended beyond liver-related outcomes, especially in this difficult-to-treat population.