Juvenile Idiopathic Arthritis Linked to Greater Prevalence of Coexisting Autoimmune Diseases

Children and young adults with juvenile idiopathic arthritis (JIA) were 54% more likely to develop 26 coexisting autoimmune diseases and other conditions when compared with the general pediatric (GP) population, according to a study published in BMJ Journals.¹

Although the causes of developing JIA are unknown, it is the most common pediatric rheumatic disease. The condition, which affects 44.7 out of 100,000 children in the US, can lead to joint damage, chronic pain, and disability.

“Many autoimmune diseases share common pathogenic mechanisms, and patients with coexisting autoimmune diseases often experience increased disease severity, disability and mortality,” investigators explained. “There are, however, limited studies quantifying the coexistence of autoimmune diseases in children and young adults with juvenile idiopathic arthritis JIA.”

This retrospective cohort study was conducted using data from the Cincinnati Children’s Hospital Medical Center (CCHMC) between January 2010 and October 2018. Eligible patients were <21 years with at least 1 clinic visit to the CCHMC. Baseline demographic information, coexisting conditions, and medication use were analyzed for patients with JIA. The Bayesian Poisson regression modelling compared and estimated prevalence rates for autoimmune diseases as well as other conditions in both the JIA and GP cohorts.

In total, data from 253,554 children and young adults were identified, with 2026 patients diagnosed with JIA and another 41,572 patients with other autoimmune diseases or associated conditions. In the JIA cohort, 1333 patients were eligible for study analysis, which consisted of patients who had at least 2 occurrences of International Classification of Diseases, Ninth or Tenth Revision, Clinical Modification (ICD-9-CM and ICD-10-CM) diagnosis codes for JIA.

Of the 26 autoimmune disease and related conditions studied, 14 (53.8%) had higher prevalence in the JIA group when compared with the GP cohort. Diseases included chronic urticaria, type 1 diabetes mellitus, autoimmune thyroiditis, vitiligo, and Addison disease. Further, 7 diseases or conditions (26.9%) had >20-fold increased prevalence in the JIA group, which included morphoea, Raynaud’s syndrome, pulmonary fibrosis/interstitial lung disease, and vasculitis.

Interestingly, patients with JIA and additional autoimmune disease skewed older at JIA onset when compared with those without additional autoimmune disease and were prescribed more non-biological and biological disease-modifying antirheumatic drugs (DMARDs), corticosteroids, and non-steroidal anti-inflammatory drugs, which may indicate a more severe disease state.

Limitations of the study included the use of electronic health record data, an inherently dynamic system, although investigators assumed that patients exited the database for reasons such as aging out of pediatric care or not be currently treated at CCHMC. Additionally, some diseases evaluated in the study may not be caused by autoimmune issues alone.

“Physicians should consider the presence of other potential autoimmune diseases in the initial work-up and ongoing evaluation of patients with JIA,” investigators concluded. “In addition, the design and analyses of future studies investigating the development of additional autoimmune diseases and associated conditions following treatment in patients with JIA should incorporate the inherent increased risk of other autoimmune diseases in this population.”

Reference:

Lovell DJ, Huang B, Chen C, Angeles-Han ST, Simon TA, Brunner HI. Prevalence of autoimmune diseases and other associated conditions in children and young adults with juvenile idiopathic arthritis. RMD Open. 2021;7(1):e001435. doi:10.1136/rmdopen-2020-001435