Geographic Variation in Disease Burden and Mismatch in Care of Patients With Rheumatoid Arthritis in the United States.

Objective: Our objective was to evaluate the factors associated with regional variation of rheumatoid arthritis (RA) disease burden in the US.

Methods: In a retrospective cohort analysis of Rheumatology Informatics System for Effectiveness (RISE) registry data, seropositivity, RA disease activity (Clinical Disease Activity Index [CDAI], Routine Assessment of Patient Index Data-version 3 [RAPID3]), socioeconomic status (SES), geographic region, health insurance type, and comorbidity burden were recorded. An Area Deprivation Index score of more than 80 defined low SES. Median travel distance to practice sites' zip codes was calculated. Linear regression was used to analyze associations between RA disease activity and comorbidity adjusting for age, sex, geographic region, race, and insurance type.

Results: Enrollment data for 184,722 patients with RA from 182 RISE sites were analyzed. Disease activity was higher in African American patients, in those from Southern regions, and in those with Medicaid or Medicare coverage. Greater comorbidity was prevalent in patients in the South and those with Medicare or Medicaid coverage. There was moderate correlation between comorbidity and disease activity (Pearson coefficient: RAPID3 0.28, CDAI 0.15). High-deprivation areas were mainly in the South. Less than 10% of all participating practices cared for more than 50% of all Medicaid recipients. Patients living more than 200 miles away from specialist care were located mainly in Southern and Western regions.

Conclusion: A disproportionately large portion of socially deprived, high comorbidity, and Medicaid-covered patients with RA were cared for by a minority of rheumatology practices. Studies are needed in high-deprivation areas to establish more equitable distribution of specialty care for patients with RA.