Regional Differences in Emergency Medical Services Use for Patients with Acute Stroke (Findings from the National Hospital Ambulatory Medical Care Survey Emergency Department Data File)

Abstract

Our objectives were to describe the proportion of stroke patients who arrive by ambulance nationwide and to examine regional differences and factors associated with the mode of transport to the emergency department (ED). Patients with a primary discharge diagnosis of stroke based on previously validated International Classification of Disease, 9th revision codes were abstracted from the National Hospital Ambulatory Medical Care Survey for the years 2007 to 2009. We excluded subjects<18 years of age and those with missing data. Using logistic regression, we identified independent predictors of arrival by ambulance to the ED. Overall, 566 patients met the entry criteria, representing 2,153,234 patient records nationally, based on 2010 US census data. Of these, 50.4% arrived by ambulance. After adjustment for potential confounders, age was associated with use of an ambulance. In addition, patients residing in the west and south had lower odds of arriving by ambulance for stroke when compared to northeast (South: odds ratio [OR] 0.45 and 95% confidence interval [CI] 0.26-0.76; West: OR 0.45 and 95% CI 0.25-0.84; Midwest: OR 0.56 and 95% CI 0.31-1.01). Compared to the Medicare population, privately insured and self-insured patients had lower odds of arriving by ambulance (OR for private insurance 0.48 and 95% CI 0.28-0.84; OR for self-payers 0.36 and 95% CI 0.14-0.93). Gender, race, urban or rural location of ED, and safety net status was not independently associated with ambulance use. Patients with stroke arrive by ambulance more frequently in the Northeast than in other regions of the United States. Identifying reasons for this difference may be useful in improving stroke care.