New Diagnoses of Juvenile Idiopathic Arthritis Early in the COVID-19 Pandemic: Analysis of a Large United States Commercial Insurance Database.

Background/objective: Little is known about the rates of rheumatic disease diagnosis among children during the COVID-19 pandemic. We examined the impact of the pandemic on the diagnosis of juvenile idiopathic arthritis (JIA) in the United States.

Methods: We performed a historical cohort study using US commercial insurance data (2016-2021) to identify children aged <18 years without prior JIA diagnosis or treatment in the prior ≥12 months. New JIA diagnoses were identified using a combination of ICD-10-CM diagnosis codes, location, and timing of medical services. Crude rates with 95% confidence intervals (CIs) of JIA diagnosis per 100,000 enrolled children per quarter were estimated and stratified by age group, sex, region, JIA type, and uveitis. The incidence rate ratio (95% CI) for JIA diagnosis was estimated using Poisson regression, adjusted for various demographic variables.

Results: From 2018-2021, 643 children were diagnosed with JIA. Crude new JIA diagnoses per 100,000 children per quarter dropped from 2.62 (95% CI, 2.39-2.87) prepandemic to 1.94 (95% CI, 1.66-2.25) during the pandemic. Declines in JIA diagnosis were more apparent in the US Northeast and West regions and among children aged 6-11 years. After adjustment for covariates, JIA diagnoses fell by 30% during the pandemic compared with the prior 3 years (IRR, 0.70; 95% CI, 0.59-0.83).

Conclusions: Compared with the prepandemic period, JIA was diagnosed 30% less often during the early pandemic among commercially insured children in the United States. More research is needed to understand the underlying reasons for these changes in JIA diagnosis and more recent trends.