The impact of a new Emergency Department on healthcare utilization by Delaware Medicaid clients: an application of the travel cost method

Solano, PaulA new Emergency Department (ED) opened in Middletown, Delaware in 2013. This research used two years of data from a balanced panel of Medicaid clients to compare healthcare utilization, including ED use, from one year before and one year after the opening of the new ED. Since out-of-pocket expenses for an ED visit are low, travel time represents one of the Medicaid client’s main “costs” and can drive increased ED use, including potential over-use for non-emergent issues. This research sought to answer the following question: What was the impact of a new Emergency Department on healthcare utilization by Delaware Medicaid clients? Methods included geospatial analysis and service area computation in ArcGIS, the application of the NYU ED visit severity algorithm, logistic regression to model the likelihood of having at least one ED visit, and negative binomial regression and seemingly unrelated regression (SUR) to model the count of ED visits. Results showed that a reduction in travel time was associated with significantly increased ED use, and lower diagnosis acuity. Medicaid clients in the vicinity of the new ED, as measured by zip code of residence and drive time calculated in ArcGIS, showed sharply increased likelihood of an ED visit and a lower acuity of the average diagnosis as estimated by the NYU ED visit severity algorithm. Utilization of other physician office visits and hospitalizations were not significantly affected, but a localized decrease in urgent care center use was observed. These results could help public health officials anticipate demand for ED services based on Medicaid clients’ geographic distribution.University of Delaware, School of Public Policy and AdministrationPh.D