Date of Award

January 2026

Document Type

Thesis

Degree Name

Medical Doctor (MD)

Department

Medicine

First Advisor

Walter S. Mathis

Abstract

BackgroundRural hospital closures have resulted in geographic disparities in access to ED-based care for rural patients and increased ED volumes at remaining hospitals in the geographic area. Geographic disparities in access to care intersect with and exacerbate other sociodemographic health disparities. This study examines patterns in rural patient utilization of rural vs urban hospitals. Given that these patients travel for care, we are also interested in how far they travel for this care. The Centers for Medicare & Medicaid Services created the new rural emergency hospital (REH) payer designation to bolster the financial solvency of rural hospitals at risk of closure. Hospitals converting to REH designation must maintain ED services but are required to eliminate inpatient services. We examined how REH conversion vs. non conversion is likely to affect travel time to acute care hospital ED and inpatient care. Research aims To identify trends in which rural patients seek care at rural vs. urban ED’s To quantify the change in drive time if hospitals were to convert to REH status Questions 1. What are the characteristics of rural patients who seek care at urban hospitals? 2. How much farther would patients have to travel if their closest hospital were to convert to REH status? Methods To investigate question 1, we conducted a cross-sectional study using the 2019 National Emergency Department Sample. Our primary outcome was emergency department visit location (rural vs. urban). Predictors of interest were patient residence (rural vs. urban), race and ethnicity, ZIP-level median household income, sex, payer, and primary diagnosis. Univariate and multivariate logistic regression were used to estimate the odds of a rural patient visiting an urban ED (vs. rural ED). To investigate question 2: We defined empirically derived hospital catchment areas using a travel-time–based approach. The contiguous United States was divided into approximately 8.1 million census blocks. For each block, straight-line (Haversine) distances to all hospitals were computed, and the five nearest hospitals were selected for driving time estimation using Open Source Routing Machine (OSRM). Each block was assigned to the hospital with the minimum travel time, and blocks sharing the same hospital defined its catchment area. We summarized minimum travel times for Critical Access Hospitals (CAHs) and evaluated changes following conversion to Rural Emergency Hospital (REH) status or hospital closure. Results Our sample for question 1 included 26,279,665 visits to 962 hospitals. Of total ED visits, 17% were made by rural patients (83% urban patients). Rural patients were primarily white (79%) and lived in zip codes with the lowest median household income quartile (58%). Overall, less than one in five (19%) of rural patient visits were at urban ED’s. Among rural patients, urban ED visit rates were higher for Emergency Care-Sensitive Conditions (e.g. sepsis/SIRS = 33%) than low-acuity conditions (e.g. otitis externa = 15%). Among rural patients, odds of visiting an urban ED was highest for patients from the wealthiest ZIP codes (OR 2.40; 95%CI 2.37, 2.43), Hispanic patients (OR 1.40; 95% CI 1.39, 1.41), those aged > 65 (OR1.11; 95% CI 1.10, 1.12), and males (OR 1.08; 95% CI 1.08, 1.09). Rural patients with Medicaid had the lowest odds of visiting an urban ED (OR 0.70; 95% CI 0.69, 0.70). Our sample for question 2 included 60 predicted REH hospitals and 110,994 census blocks that fell within their catchment. The median travel time from census blocks to REHs (which currently have access to both ED and inpatient care) was 24.7 min (IQR 13.4, 36.7). If predicted REHs didn’t convert and closed, travel time to the nearest ED would increase to 56.6 min (IQR 39.5, 87.1). If predicted REHs did convert and eliminate inpatient services, the travel time to the nearest inpatient facility would increase to 56.8 min (IQR 39.8, 88.0). Statement of scientific impact This work serves to investigate how rural patients seek care, especially across geographic space. Better understanding of the lengths patients must travel to receive care has ramifications on other research works, future policies, and patient health. The Rural Emergency Hospital Designation has the potential to reshape how rural patients receive care and where they must travel to get it. This work hopes to highlight a component of this cost-benefit analysis.

Comments

This thesis is restricted to Yale network users only. It will be made publicly available on 07/14/2028

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