Impact of hepatitis C treatment status on risk of Parkinson's disease and secondary parkinsonism in the era of direct-acting antivirals

Research progress on Helicobacter pylori infection related neurological diseases

Helicobacter pylori, a type of gram-negative bacterium, infects roughly half of the global population. It is strongly associated with gastrointestinal disorders like gastric cancer, peptic ulcers, and chronic gastritis. Moreover, numerous studies have linked this bacterium to various extra-gastric conditions, including hematologic, cardiovascular, and neurological issues. Specifically, research has shown that Helicobacter pylori interacts with the brain through the microbiota-gut-brain axis, thereby increasing the risk of neurological disorders. The inflammatory mediators released by Helicobacter pylori-induced chronic gastritis may disrupt the function of the blood-brain barrier by interfering with the transmission or direct action of neurotransmitters. This article examines the correlation between Helicobacter pylori and a range of conditions, such as hyperhomocysteinemia, schizophrenia, Alzheimer's disease, Parkinson's disease, ischemic stroke, multiple sclerosis, migraine, and Guillain-Barré syndrome.

Elucidating the association between direct-acting antivirals and Parkinson's disease in patients with hepatitis C virus infection

BACKGROUND

Some epidemiological studies have found an increased association between Parkinson's disease (PD) and chronic hepatitis C virus (HCV) infection. Although a few studies have also found a decreased risk of PD with interferon-α therapy, the effect of direct-acting antivirals (DAAs) on Parkinson's disease remains unclear. The current study seeks to assess and elucidate the association between DAAs and PD in patients newly diagnosed with chronic HCV infection.

METHODS

We conducted a retrospective cohort study of patients ≥18 years diagnosed with HCV using MarketScan Commercial and Medicare Supplemental database (2012-2019). Follow-up started with the initiation of DAA (or randomly assigned date for the non-DAA group) and ended at occurrence of PD, disenrollment, or end of the study period. A multivariable Cox proportional hazards model was used to estimate hazard ratios (HR) and 95% confidence intervals.

RESULTS

We identified 48,356 patients diagnosed with HCV. The mean follow-up time of the cohort was 1.31 years. The incidence rate of PD was 53 per 100,000 person-years for the DAA group and 48 per 100,000 person-years for the non-DAA group. The adjusted HR was 1.24 (95% CI = 0.56-2.73). Results were consistent across sensitivity and subgroup analyses.

CONCLUSION

This study did not find an association between DAAs and PD among patients with HCV infection.

Antiviral Treatment and Response are Associated With Lower Risk of Dementia Among Hepatitis C Virus-Infected Patients

OBJECTIVE

Eradication of hepatitis C virus (HCV) infection has been linked with improvement in neurocognitive function, but few studies have evaluated the effect of antiviral treatment/ response on risk of dementia. Using data from the Chronic Hepatitis Cohort Study (CHeCS), we investigated how antiviral therapy impacts the risk of developing dementia among patients with HCV.

METHODS

A total of 17,485 HCV patients were followed until incidence of dementia, death, or last follow-up. We used an extended landmark modeling approach, which included time-varying covariates and propensity score justification for treatment selection bias, as well as generalized estimating equations (GEE) with a link function as multinominal distribution for a discrete time-to-event data. Death was considered a competing risk.

RESULTS

After 15 years of follow-up, 342 patients were diagnosed with incident dementia. Patients who achieved sustained virological response (SVR) had significantly decreased risk of dementia compared to untreated patients, with hazard ratios (HRs) of 0.32 (95% CI 0.22-0.46) among patients who received direct-acting antiviral (DAA) treatment and 0.41 (95% CI 0.26-0.60) for interferon-based (IFN) treatment. Risk reduction remained even when patients failed antiviral treatment (HR 0.38, 95% CI 0.38-0.51). Patients with cirrhosis, Black/African American patients, and those without private insurance were at significantly higher risk of dementia.

CONCLUSION

Antiviral treatment independently reduced the risk of dementia among HCV patients, regardless of cirrhosis. Our findings support the importance of initiation antiviral therapy in chronic HCV-infected patients.