Background/Purpose: Extreme sociodemographic disparities exist among systemic lupus erythematosus (SLE) patients in the development of end-stage renal disease (ESRD) from lupus nephritis. Better resource allocation and improved access to care may reduce the incidence of this adverse outcome. We aimed to understand sociodemographic variation in health care utilization prior to ESRD development among SLE patients enrolled in Medicaid, U.S. health insurance for low income individuals.

Methods: From the Medicaid Analytic eXtract (MAX) data containing all U.S. Medicaid billing claims from 2000-2004, we identified adults, ages 18 to 65 years, diagnosed with SLE (≥3 visits, ICD-9 code 710.0, >30 days apart). To determine progression to ESRD we matched these individuals with SLE to the U.S. Renal Data System (USRDS), which contains information on nearly all ESRD patients from 2000-2004. We assessed duration of Medicaid enrollment prior to ESRD onset, and age, sex, race/ethnicity and U.S. region for each individual. We determined residence in a Health Professional Shortage Area, number of rheumatologists per state, and county-level socioeconomic status (SES) using a previously validated composite score of 7 U.S. Census variables. We examined 3 outcomes: emergency department (ED), outpatient and inpatient visits per year. We used multivariate-adjusted general linear models to understand the relationship between sociodemographic factors and these health care utilization outcomes.

Results: Of the 34,339 adults with SLE enrolled in Medicaid, 1,475 (4.3%) developed ESRD during the study period. 86% were female, the mean age of ESRD onset was 30.7 years (SD 11.6), and 58.9% were African American, 17.4% were White and 16.1% were Hispanic. The mean number of months in Medicaid prior to ESRD diagnosis was 23.4 (SD 16.4). There were an average of 2.2 (SD 3.2) ED visits, 10 (SD 9.5) outpatient visits and 2.3 (SD 3.0) inpatient visits per year. In multivariate models, men had significantly fewer annual outpatient visits than women (p<0.001). Asian patients had nearly 1 less ED visit per year (p=0.03) and 2.4 fewer outpatient visits per year (p=0.05), compared to Whites. There were more annual ED visits in the Midwest (p=0.01), and outpatient visits in the Midwest (p=0.001) and West (p<0.001), compared to the Northeast. Patients in the lowest county-level SES group had significantly more ED visits per year than the highest SES group (p=0.02). There were no significant differences in inpatient visits according to the sociodemographic groups examined by multivariate analysis.

Conclusion: In this nationwide cohort of Medicaid enrollees with SLE who developed ESRD, we observed significant variation in ED and outpatient visits by sex, race/ethnicity, region, and county-level SES.  Increased ED visits in low SES areas may indicate a lack of sustained access to subspecialty care. Further studies are needed to determine whether differences in health care utilization, particularly in underserved areas, contribute to increased rates of progression to ESRD in this high-risk population.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/health-care-utilization-among-medicaid-enrollees-with-systemic-lupus-erythematosus-preceding-the-development-of-end-stage-renal-disease-sociodemographic-variation/