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Parkinson’s disease rates lower in patients treated vs. untreated for HCV

Patients who received interferon-based antiviral therapy for chronic hepatitis C had a significantly lower incidence rate of Parkinson’s disease compared with untreated patients, according to an analysis published in JAMA Neurology.

“Chronic HCV infection not only affects the liver but also is a risk factor in extrahepatic diseases, such as diabetes, chronic kidney disease, atherosclerosis, coronary artery disease, and stroke,” Wey-Yil Lin, MD, from the Landseed International Hospital in Taiwan, and colleagues wrote. “The lower rate of [Parkinson’s disease (PD)] occurrence in the treated patients may suggest that HCV infection is a risk factor for PD development, and antiviral therapy lowers the risk.”

The study comprised 39,936 patients who received treatment matched with 39,936 patients who did not. Mean age of patients in each group was about 52 years and both groups comprised about 45% women.

The incidence density of PD was 1 (95% CI, 0.85-1.15) in the treated group and 1.39 (95% CI, 1.21-1.57) per 1,000 person-years in the untreated group. Additionally, the risk for PD between cohorts was different at 5 years of follow-up (HR = 0.75; 95% CI, 0.59-0.96) and the end of the trial, which was approximately 10 years (HR = 0.71; 95% CI, 0.58-0.87).

While the event number and incidence density increased gradually over time in both groups, the event rate was slower in the treated group (3.03 per 1,000 to 4.06 per 1,000) compared with the untreated group (3.93 per 1,000 to 5.51 per 1,000).

“The underlying mechanism of the protective potential of interferon-based antiviral therapy could be complicated and may involve the modulation of anti-inflammatory cytokines,” Lin and colleagues wrote. “In contrast, the reduced incidence of PD by antiviral therapy could be associated with the reduction or clearance of HCV in patients.”

Going forward, the researchers recommend a cohort study with a longer follow-up period and prospective studies assessing the correlation between PD, viral genotype, RNA level, and severity of hepatic disease among patients with chronic HCV. – by Talitha Bennett

Disclosure: The authors report no relevant financial disclosures.