Although health disparities are prevalent in many chronic diseases, including rheumatic diseases like rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE), they remain poorly understood in pediatric rheumatology. 

Two analyses^1,2 conducted by the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Registry have highlighted important disparities among children with polyarticular juvenile idiopathic arthritis (pJIA.

In these studies, 1684 children with pJIA were identified in the CARRA Registry between July 2015 and February 2020. The study participants were primarily girls (79%), with a median age at diagnosis of 7 years (IQR, 3-11 years).

A total of 72% were rheumatoid factor (RF)-negative and 47% were anticitric citrullinated protein (CCP)-negative. Among the cohort, 74% identified as White, 10% identified as Hispanic/Latinx/Spanish origin, and 4% identified as Black/African/American/African/Afro Caribbean.

In the first study,¹ Cox proportional hazards regression was performed to analyze the impact of community poverty level, defined as 20% or more of the population living below the federal poverty limit, on time to first presentation to a pediatric rheumatologist. Delays were identified with an adjusted hazard ratio: 0.81 (95% CI, 0.67-0.99), controlling for age, sex, race/ethnicity, insurance status, education level, morning stiffness, RF status, and baseline Child Health Assessment Questionnaire (CHAQ) score. 

In the follow-up study,² community poverty was not associated with persistent functional disability (as measured by the CHAQ) or moderate to severe disease activity (as measured by the Clinical Juvenile Arthritis Disease Activity Score [cJADAS]).  However, low individual income level was associated with persistent functional disability (earning $50,000-$99,999/year compared with less than $25,000/year: adjusted odds ratio [aOR], 0.49; 95% CI, 0.28-0.85) and persistent functional disability (earning >$100,000/year compared with <$25,000: aOR, 0.27; 95% CI, 0.13-0.55) across the first year of treatment. In addition, non-White race was associated with higher disease activity (aOR, 2.48; 95% CI, 1.41-4.36), and public insurance and guardian education of high school or lesser were associated with both functional disability and persistent moderate to severe disease activity across the first year of treatment. In general, however, both CHAQ and cJADAS scores improved between baseline, 6 months, and 12 months across the study cohort. 

Both these studies suggest that disparities are prevalent among children with polyarticular JIA and, importantly, impact different timepoints of disease, which may suggest multiple windows for intervention.

In the first analysis, disparities in polyarticular JIA were evident before establishing care with a pediatric rheumatologist, with statistically significant delays among those living in poverty. There are several steps that occur between disease onset and presentation to a pediatric rheumatologist, including development of symptoms, recognition of symptoms, evaluation by a primary care physician, referral to rheumatology, and the waiting period between placing the referral and first rheumatology visit. The analysis did not address which of these steps may be affected most by poverty leading to delays, though interventions that target expediting the recognition of arthritis and referral to a rheumatologist among low-income communities could be hypothesized to ameliorate this disparity and should be the subject of future intervention efforts. 

Nevertheless, disparities are prevalent even for those children in the care of a rheumatologist across the first year of treatment. Public insurance, low guardian education level, and low-income level were identified to be important predictors of disease activity or disability. Regardless of background or socioeconomic means, all children with arthritis in the care of a rheumatologist should have equitable care and opportunity for long-term success.

Multiple social determinants were identified¹ as contributing to disparities in pJIA outcomes, and each individually may warrant separate interventions. For example, health literacy efforts may be most beneficial for children from families with high school education or lesser. More research is needed to better understand the interrelationships between multiple social determinants of health in determining outcomes for children with polyarticular JIA to identify the most meaningful targets for intervention. Regardless, hypothesized interventions that may address multiple social determinants might include targeted social risk screening in pediatric rheumatology clinic and the use of patient navigators to aid in the management of chronic disease.

The analyses did not address delays in escalating therapy, such as starting a biologic, which may impact disease outcomes and could be an important intervention point, if disparities here are considered.