Patients with Inflammatory Bowel Disease Are at an Increased Risk of Parkinson's Disease: A South Korean Nationwide Population-Based Study

Background and Aims: It is not known whether inflammatory bowel disease (IBD) enhances the risk of Parkinson's disease (PD) or whether PD diagnosis is the result of increased health care use. We determined the risk of developing PD among patients with IBD in terms of health care and medication use. Methods: A nationwide population-based study was conducted using claims data from the Korean National Health care Insurance service. From 2010 to 2013, patients with Crohn's disease (CD) and ulcerative colitis (UC) were identified through both International Classification of Disease, Tenth Revision (ICD-10) and national rare intractable disease (RID) registration program codes. We compared 38,861 IBD patients with age and sex-matched non-IBD individuals at a ratio of 1:3. Patients with newly diagnosed PD were identified through both ICD-10 and RID codes. Results: The incidence of PD among patients with IBD was 49 per 100,000 person-years. The risk of developing PD in patients with IBD was significantly higher than controls even after adjustment for health care use (adjusted hazard ratio (aHR), 1.87; P < 0.001). Compared to controls, the risk of PD was significantly higher in patients with CD (aHR, 2.23; P = 0.023) and UC (aHR, 1.85; P < 0.001). Corticosteroid use showed a preventive effect on developing PD in patients with CD (aHR 0.08; P < 0.001), but not UC (aHR, 0.75; P = 0.213). Among 2110 patients receiving anti-tumor necrosis factor (anti-TNF), none of the treated patients experienced PD during 9950 person-years. Conclusion: Patients with IBD are at an increased risk of PD, regardless of health care use. Corticosteroid and anti-TNF use may prevent PD in patients with IBD.