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Primary Submission Category: Health care/services
Characterizing ED “Super-Utilizers” among Undocumented Immigrants in the Health Care Safety Net
Authors: Ahalya Prakash, Annie Ro, Jung Min Choi,
Presenting Author: Ahalya Prakash*
Introduction: Approximately 10.2 million undocumented immigrants in the U.S. are not eligible for Medicaid, limiting their access to preventive care and increasing their reliance on emergency departments (ED). Programs such as My Health LA (MHLA) provide primary care to mostly undocumented adults in Los Angeles County, though structural barriers and delayed care persist, leading to severe or repeat ED visits. Identifying ED “super-users” is critical for optimizing healthcare resources and informing cost considerations as California expands Medi-Cal coverage to undocumented immigrants.
Data & Methods: ED utilization was examined using merged MHLA enrollment, Medi-Cal claims (MICRS), and electronic health record data from Los Angeles County Department of Health Services hospitals (2014–2023). The sample included 51,656 MHLA enrollees with ≥1 ED visit. ED use was categorized as low (0–3 visits/year), high (4–9), or super (≥10).
Results: ED users had a mean age of 46 years and were predominantly female (61.4%), Spanish-speaking (91.1%), Hispanic (69.6%), and from Mexico (68.7%), Guatemala (11.6%), or El Salvador (9.8%); most were not homeless (69.6%; 1.5% homeless). Patients averaged 8.4 primary care visits, 1.6 ED visits, and 4.2 years of MHLA enrollment. Overall, 89.7% were low utilizers, 9.57% high, and 0.69% super-utilizers. Super-utilizers were older (49 vs 48.5 vs 45.6; F=338.86, p<0.0001), more likely male (57.8% vs 44.1% vs 37.8%; χ²=292.02, p<0.0001), had more primary care visits (5.03 vs 4.78 vs 4.14; F=515.27, p<0.0001), but shorter MHLA enrollment (3.5 vs 3.8 vs 4.23 years; F=211.43, p<0.0001). Multinomial regression will examine predictors of ED utilization controlling for relevant covariates.
Conclusion: Although <1% of patients were super-utilizers, they accounted for a disproportionate share of ED visits. Characterizing these high utilizers may help inform targeted interventions and improve care continuity within safety-net systems as Medi-Cal expands.