LAUSR

Research suggests a possible link between chronic infection with hepatitis C virus (HCV) and the development of Parkinson's Disease (PD) and secondary Parkinsonism (PKM). We investigated the impact of antiviral treatment status (untreated, interferon [IFN] treated, direct‐acting antiviral [DAA] treated) and outcome (treatment failure [TF] or sustained virological response [SVR]) on risk of PD/PKM among patients with HCV. Using data from the Chronic Hepatitis Cohort Study (CHeCS), we applied a discrete time‐to‐event approach with PD/PKM as the outcome. We performed univariate followed by a multivariable modelling that used time‐varying covariates, propensity scores to adjust for potential treatment selection bias and death as a competing risk. Among 17,199 confirmed HCV patients, we observed 54 incident cases of PD/PKM during a mean follow‐up period of 17 years; 3753 patients died during follow‐up. There was no significant association between treatment status/outcome and risk of PD/PKM. Type 2 diabetes tripled risk (hazard ratio [HR] 3.05; 95% CI 1.75–5.32; p < .0001) and presence of cirrhosis doubled risk of PD/PKM (HR 2.13, 95% CI 1.31–3.47). BMI >30 was associated with roughly 50% lower risk of PD/PKM than BMI <25 (HR 0.43; 0.22–0.84; p = .0138). After adjustment for treatment selection bias, we did not observe a significant association between HCV patients' antiviral treatment status/outcome on risk of PD/PKM. Several clinical risk factors—diabetes, cirrhosis and BMI—were associated with PD/PKM.