[Skip to Content]
[Skip to Content Landing]
Views 6,628
Citations 0
Original Investigation
October 2018

Variation in Survival After Out-of-Hospital Cardiac Arrest Between Emergency Medical Services Agencies

Author Affiliations
  • 1Department of Emergency Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
  • 2Clinical Trial Center, Department of Biostatistics, University of Washington, Seattle
  • 3Department of Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
  • 4Department of Emergency Medicine, University of Texas Southwestern Medical Center, Dallas
  • 5Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas
  • 6University of Washington–Harborview Center for Prehospital Emergency Care, Seattle
  • 7Department of Emergency Medicine, The Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada
  • 8Department of Emergency Medicine, University of British Columbia, Vancouver, British Columbia, Canada
  • 9Clark County Emergency Medical Services, Vancouver, Washington
  • 10MedStar, Inc, Fort Worth, Texas
  • 11Rescu, Li Ka Shing Knowledge Institute, St Michael’s Hospital, Division of Emergency Medicine, Department of Family and Community Medicine, University of Toronto, Toronto, Ontario, Canada
  • 12Department of Emergency Medicine, University of Alabama at Birmingham
  • 13Division of Cardiology, Department of Medicine, University of Washington, Seattle
  • 14Department of Emergency Medicine, Oregon Health and Science University, Portland
  • 15Department of Emergency Medicine, Medical College of Wisconsin, Milwaukee
  • 16Department of Emergency Medicine, University of Texas Health Science Center at Houston, Houston
  • 17Department of Emergency Medicine, University of California, San Diego
  • 18Department of Medicine, Johns Hopkins University, Baltimore, Maryland
JAMA Cardiol. 2018;3(10):989-999. doi:10.1001/jamacardio.2018.3037
Key Points

Question  What is the variation in survival after out-of-hospital cardiac arrest between emergency medical services (EMS) agencies?

Findings  In this cohort study, among 43 656 adults treated for out-of-hospital cardiac arrest by any of 112 EMS agencies, there was a median difference of 56% in the odds of survival to hospital discharge for similar participants between any 2 randomly selected EMS agencies, after adjusting for known measured sources of variability and clustering of patients within agencies.

Meaning  This study suggests there is substantial unexplained variation in survival after out-of-hospital cardiac arrest across treating EMS agencies in North America, despite controlling for documented patient and agency characteristics.

Abstract

Importance  Emergency medical services (EMS) deliver essential initial care for patients with out-of-hospital cardiac arrest (OHCA), but the extent to which patient outcomes vary between different EMS agencies is not fully understood.

Objective  To quantify variation in patient outcomes after OHCA across EMS agencies.

Design, Setting, and Participants  This observational cohort study was conducted in the Resuscitation Outcomes Consortium (ROC) Epistry, a prospective multicenter OHCA registry at 10 sites in North America. Any adult with OHCA treated by an EMS from April 2011 through June 2015 was included. Data analysis occurred from May 2017 to March 2018.

Exposure  Treating EMS agency.

Main Outcomes and Measures  The primary outcome was survival to hospital discharge. Secondary outcomes were return of spontaneous circulation at emergency department arrival and favorable functional outcome at hospital discharge (defined as a modified Rankin scale score ≤3). Multivariable hierarchical logistic regression models were used to adjust confounders and clustering of patients within EMS agencies, and calculated median odds ratios (MORs) were used to quantify the extent of residual variation in outcomes between EMS agencies.

Results  We identified 43 656 patients with OHCA treated by 112 EMS agencies. At EMS agency level, we observed large variations in survival to hospital discharge (range, 0%-28.9%; unadjusted MOR, 1.43 [95% CI, 1.34-1.54]), return of spontaneous circulation on emergency department arrival (range, 9.0%-57.1%; unadjusted MOR, 1.53 [95% CI, 1.43-1.65]), and favorable functional outcome (range, 0%-20.4%; unadjusted MOR, 1.54 [95% CI, 1.40-1.73]). This variation persisted despite adjustment for patient-level and EMS agency–level factors known to be associated with outcomes (adjusted MOR for survival 1.56 [95% CI 1.44-1.73]; adjusted MOR for return of spontaneous circulation at emergency department arrival, 1.50 [95% CI, 1.41-1.62]; adjusted MOR for functionally favorable survival, 1.53 [95% CI, 1.37-1.78]). After restricting analysis to those who survived more than 60 minutes after hospital arrival and including hospital treatment characteristics, the variation persisted (adjusted MOR for survival, 1.49 [95% CI, 1.36-1.69]; adjusted MOR for functionally favorable survival, 1.34 [95% CI, 1.20-1.59]).

Conclusions and Relevance  We found substantial variations in patient outcomes after OHCA between a large group of EMS agencies in North America that were not explained by documented patient-level and EMS agency–level variables.

×