SAT0489 PREVALENCE OF AUTOIMMUNE DISEASES IN PATIENTS WITH JUVENILE IDIOPATHIC ARTHRITIS

Abstract

Background Juvenile idiopathic arthritis (JIA) is one of at least 80 different types of autoimmune diseases, and is the most common paediatric rheumatic disease. After cancer and heart disease, autoimmune diseases are the most common type of disease in the US. The estimated prevalence of autoimmune diseases is 3.2% and 5.9% in the US1 and Europe,2 respectively, with a corresponding increase in mortality.3 Many autoimmune diseases share a common pathogenic mechanism. There are few published studies quantifying the occurrence of other autoimmune diseases in patients with JIA. Objectives To estimate and compare the prevalence of 38 co-existing autoimmune diseases in patients with JIA and in a general paediatric population. Methods This was a retrospective cohort study conducted using registry data from the Cincinnati Children’s Hospital Medical Center (CCHMC; Cincinnati, OH, USA) from Jan 2010 to Oct 2018. Patients Comparisons were made between the JIA and the GP cohorts for each of the 38 AICs in crude prevalence (reported as X cases per patient-year) for each year up to the end of the study period. A Bayesian Poisson regression model was used for estimating and comparing prevalence rates for the JIA and GP cohorts at the end of study period. The rate and corresponding 95% confidence limits of the two cohorts on their prevalence rates are reported. Results There were 2,026 and 41,572 patients included in the JIA and GP cohorts, respectively. Out of 38 AICs, 26 showed significantly higher prevalence in the JIA cohort compared with the GP cohort (Figure). Of the 38 ICD9/10 codes assessed, 14 (36.8%) showed a more than 20-fold greater prevalence in the JIA cohort than in the GP cohort. There were statistically significant differences in 26 conditions (Figure), with the most striking differences comparing the GP cohort with the JIA cohort in ankylosing spondylitis (0.001% vs 0.98%), psoriatic arthritis (0.01% vs 4.44%), systemic sclerosis/scleroderma (0.004% vs 0.6%), uveitis (0.07% vs 7.82%) and sarcoidosis (0.003% vs 0.3%). Only alopecia areata was more frequent in the GP cohort than in patients with JIA (4.5% vs 0.2%). Conclusion Patients with JIA have more pronounced autoimmunity prevalence than the general paediatric population, especially for ankylosing spondylitis, psoriatic arthritis, uveitis, systemic sclerosis/scleroderma and sarcoidosis.