Background: Parkinson’s disease (PD) is the second most common neurodegenerative disease worldwide and affects more than 1 million people in the United States. Some epidemiological studies have reported an increased risk of PD in patients with chronic hepatitis C virus (HCV). The effect of HCV treatment on the incidence of PD, however, is still unknown.
Objectives: To assess the association between direct-acting antivirals (DAAs) therapy and risk of developing PD in patients newly diagnosed with chronic HCV.
Methods: We conducted a retrospective cohort study of patients ≥ 18 years newly diagnosed with chronic HCV using MarketScan Commercial and Medicare Supplemental database (2012-2019). Index date was defined as the first DAA prescription date for patients in the DAA group; for patients in the non-DAA group, we assigned the index date using prescription time distribution matching based on the number of days from first HCV diagnosis to first DAA prescription. Follow-up continued until the occurrence of PD, disenrollment, or end of the study period. A multivariable Cox proportional hazards models with IPTW were used to estimate HRs and 95% CIs. Sensitivity analyses (e.g., change in criteria used for PD ascertainment) and subgroup analyses (e.g., age, sex, presence of head trauma) were conducted.
Results: We identified 47,846 patients newly diagnosed with HCV: 34.3% in the DAA group (mean age: 54.8 14 years and 59.6% male) and 65.7% in the non-DAA group (mean age: 55.3 12.3 years and 59% male). The incidence rate of PD was 53 per 100,000 person-years in the DAA group and 48 per 100,000 person-years in the non-DAA group. The mean follow-up time of the cohort was 1.31 person-years. Compared to the non-DAA group, no difference in the risk of developing PD was observed in the in the DAA group (adjusted HR= 1.24, 95% CI=0.56-2.73). When defining PD based on at least 2 prescription claims of PD-related medications, the adjusted risk of developing PD was 1.18 (95% CI=0.85-1.63) for the DAA group compared to the non-DAA group. Results were consistent across different subgroup analyses.
Conclusions: This population-based analysis suggested that DAA use was not associated with decreased risk of developing PD among patients with newly diagnosed HCV. Future studies investigating the longer-term effects of DAAs on PD are needed.
