System-level health disparities in California emergency departments: minorities and Medicaid patients are at higher risk of losing their emergency departments.

STUDY
OBJECTIVE: Emergency department (ED) closures threaten community access to emergency services, but few data exist to describe factors associated with closure. We evaluate factors associated with ED closure in California and seek to determine whether hospitals serving more vulnerable populations have a higher rate of ED closure.
METHODS: This was a retrospective cohort study of California hospital EDs between 1998 and 2008, using hospital- and patient-level data from the California Office of Statewide Health Planning and Development (OSHPD), as well as OSHPD patient discharge data. We examined the effects of hospital and patient factors on the hospital's likelihood of ED closure by using Cox proportional hazards models.
RESULTS: In 4,411 hospital-years of observation, 29 of 401 (7.2%) EDs closed. In a model adjusted for total ED visits, hospital discharges, trauma center and teaching status, ownership, operating margin, and urbanicity, hospitals with more black patients (hazard ratio [HR] 1.41 per increase in proportion of blacks by 0.1; 95% confidence interval [CI] 1.16 to 1.72) and Medi-Cal recipients (HR 1.17 per increase in proportion insured by Medi-Cal by 0.1; 95% CI 1.02 to 1.34) had higher risk of ED closure, as did for-profit institutions (HR 1.65; 95% CI 1.13 to 2.41).
CONCLUSION: The population served by EDs and hospitals' profit model are associated with ED closure. Whether our findings are a manifestation of poorer reimbursement in at-risk EDs is unclear.