Predictors of Ambulance Diversions: Do Hospitals Strategically Divert to Avoid Medicaid and Uninsured Patients

Project: Research project

Project Details


? DESCRIPTION (provided by applicant): The Emergency Medical Treatment and Labor Act (EMTALA), a condition of participation for Medicare, requires hospitals provide emergency care to all patients, regardless of insurance status. Hospitals may circumvent EMTALA by strategically temporarily closing their emergency departments (EDs) when they suspect ambulances contain indigent patients, such as when a nearby safety net hospital is on diversion. This dissertation explores whether hospitals declare these strategic diversions, and the factors driving them. Strategic diversions increase inequities due to hospitals' attempts to select an economically favorable patient mix. Additionally, because they unnecessarily restrict ED capacity, strategic diversions threaten all patients' care since delays in ED care increase mortality. This dissertation is of particular interest to AHRQ, which aims to make health care safer, more accessible, and equitable. The project will address three aims. Aim 1 is to construct a dataset that describes the temporal relationship between hospitals declaring diversions. This dataset combines data from ambulance diversion logs in California, ED and inpatient discharge data from the Office of Statewide Health Planning and Development, and from the American Hospital Association Annual Survey. Aim 2 is to examine whether hospitals engage in strategic diversions. To distinguish between these diversions and necessary, capacity-driven diversions, the study matches hospitals by size and distance, and uses multivariate probit and poisson with hospital random effects to examine diversion probability and characteristics after nearby safety net and matched non-safety net hospitals divert. Diversion characteristics include length of diversion and time elapsing between when the two hospitals end their respective diversions. The main predictor variables are the safety net status of the nearby hospital interacted with variables operationalizing ED crowding and staffing, including daily ED occupancy, and uses instrumental variables to address concerns about reverse causality. Aim 3 is to explore factors that influence whether hospitals declare strategic diversions, such as organizational culture and goals or the anticipated economic benefit of diverting. It uses the same analyses above but adds predictors about profit status, the profitability of services offered by the hospital, and the Medicaid/uninsured visits at the hospital.
Effective start/end date9/30/156/30/16


  • National Institutes of Health


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