Incidence of Chronic Immune-Mediated Inflammatory Diseases After Diagnosis with Kawasaki Disease: A Population-Based Cohort Study.

OBJECTIVES Kawasaki disease (kDa) is an immune-mediated vasculitis of childhood with multi-organ inflammation. We determined the risk of subsequent immune-mediated inflammatory disease (IMID), including arthritis, type 1 diabetes, inflammatory bowel disease (IBD), autoimmune liver disease (ALD), primary sclerosing cholangitis (PSC) and multiple sclerosis (MS). METHODS We conducted a matched population-based cohort study using health administrative data from Ontario, Canada. Children aged <18 years born between 1991-2016 diagnosed with kDa (n = 3,753) were matched to 5 non-kDa controls from the general population (n = 18 749). We determined the incidence of IMIDs after resolution of kDa. Three- and 12-month washout periods were used to exclude kDa-related symptoms. RESULTS There was an elevated risk of arthritis in kDa patients compared with non-kDa controls starting three months after index date (103.0 vs 12.7 per 100 000 person-years (PYs); incidence rate ratio (IRR) 8.07 (95% CI 4.95-13.2); hazard ratio (HR) 8.08 (95% CI 4.95-13.2), resulting in the overall incidence of IMIDs being elevated in kDa patients (175.1 vs 68.0 per 100 000 PYs; IRR 2.58 (95% CI 1.93-3.43); HR 2.58, 95% CI 1.94-3.43). However, there was no increased risk for diabetes, IBD, ALD, PSC or MS in kDa patients. Similar results were observed using a 12-month washout period. CONCLUSIONS Children diagnosed with kDa were at increased risk of arthritis following the acute kDa event, but not other IMIDs. Health care providers should monitor for arthritis in children following a diagnosis of kDa.