Anti-TNF Therapy May Reduce Risk of Parkinson Disease in Patients With IBD

While systemic inflammation is a potential biological mechanism underlying both Parkinson disease (PD) and inflammatory bowel disease (IBD)—and while the LRRK2 gene has variants that are independently recognized as associated with PD and Crohn disease (CD)—clinical data on comorbid PD and IBD are few. In a new paper published in JAMA Neurology, researchers report on a retrospective cohort study that assessed the incidence of PD among patients with IBD and sought to identify whether anti—tumor necrosis factor (anti-TNF) therapy for IBD alters the risk of PD.

The research team used deidentified data on patients with IBD, 18 years or older, that were derived from the Truven Health MarketScan Commercial Database and the Medicare Supplemental Database from 2000 to 2016. Patients with IBD were matched to 720,090 unaffected controls. Of the total number of individuals, 1796 (0.2%) had PD, and the researchers found a statistically significant 28% increase in the incidence of PD among patients with IBD compared with the control group. The increased rate of PD was observed equally among patients with ulcerative colitis (adjusted incidence rate ratio [IRR], 1.31; 95% CI, 1.14-1.51; P <.001) and CD (adjusted IRR, 1.26; 95% CI, 1.03-1.53; P =.02).

Among patients with IBD who were exposed to anti-TNF therapy (the anti-TNF agents adalimumab, certolizumab, golimumab, and infliximab were included in the analysis), there was a PD incidence rate of 0.08 per 1000 patient-years. Among patients with IBD who were not exposed to anti-TNF agents, the incidence rate of PD per 1000 patient-years was 0.76.

While the exact mechanism of PD development in patients with IBD is not known, the authors conclude that there is a potential link between IBD and PD, and that early exposure to anti-TNF therapy may reduce the risk of PD among patients with IBD, potentially due to a reduction in systemic inflammation.

“In the present study, we observed a 78% reduction in the incidence of PD among patients with IBD who were exposed to anti-TNF medications. These findings call into question the notion that existing anti-TNF therapies have limited central nervous system effects because these large molecule drugs do not cross the blood-brain barrier,” write the authors. “Targeting TNF could have disease-modifying potential in individuals at risk of PD.”

Reference

Peter I, Dubinsky M, Bressman S, et al. Anti—tumor necrosis factor therapy and incidence of Parkinson disease among patients with inflammatory bowel disease [published online April 23, 2018]. JAMA Neurol. doi: 10.1001/jamaneurol.2018.0605.