Out-of-Hospital Aspirin Administration for Acute Coronary Syndrome in the United States: An EMS Quality Assessment Using the NEMSIS (National EMS Information System) Database


      National practice guidelines recommend early aspirin administration for acute coronary syndrome (ACS) to reduce mortality. While timely administration of aspirin has shown to reduce mortality in ACS by 23%, prior regional EMS data have shown inadequate aspirin use in patients with suspected cardiac ischemia.

      Study Objectives

      Using the National EMS Information System (NEMSIS) database, we sought to determine 1) the proportion of patients with suspected cardiac ischemia who received aspirin and 2) which patient characteristics independently predicted the administration of aspirin.


      Analysis of the 2011 NEMSIS database targeted patients ≥ 40 years old with a paramedic primary impression of “chest pain.” To identify patients with chest pain of suspected cardiac etiology, we included those with an EKG or cardiac monitor performed. Trauma-related chest pain and basic life support (BLS) transports were excluded. The primary outcome was defined as the presence of aspirin administration. Patient characteristics of age, sex, ethnicity/race, insurance status, and United States region were also obtained. Multivariate logistic regression was used to assess the independent association of patient factors with aspirin administration for suspected cardiac ischemia.


      Of the total 14,371,941 EMS incidents in the 2011 database, there were 198,231 patients that met our inclusion criteria (1.3%). Of those, 45.4% received aspirin from the EMS provider. When compared to non Hispanic white patients, several groups had greater odds of aspirin administration by EMS. Non Hispanic blacks (OR 1.49, 95% CI 1.44-1.55), non Hispanic Asians (OR 1.62, 95% CI 1.21-2.18), Hispanics (OR 1.71 95% CI 1.54-1.91), and other non Hispanics (OR 1.27, 95% CI 1.07-1.51) all had greater odds of receiving aspirin. Patients living in the Southern region of the United States (OR 0.85, 95% CI 0.81-0.89) and patients with governmental insurance (OR 0.67, 95% CI 0.57-0.78) had lower odds of receiving aspirin. Age and sex (OR 1.00 95% CI 1.00-1.00) were not associated with aspirin administration.


      Our results confirmed that aspirin administration for suspected ACS could be improved. Further, there were regional, ethnic/racial, and insurance-based disparities noted in aspirin administration. The reasons for withholding aspirin were not identified in this analysis. Further qualitative assessment of these practice variations will help identify and develop interventions to improve quality of out-of-hospital ACS care.