Elsevier

Annals of Emergency Medicine

Volume 70, Issue 3, September 2017, Pages 366-373.e3
Annals of Emergency Medicine

Emergency medical services/original research
Long-Term Mortality of Emergency Medical Services Patients

Presented at the Resuscitation 2015 conference, October 2015, Prague, Czech Republic.
https://doi.org/10.1016/j.annemergmed.2016.12.017Get rights and content

Study objective

Emergency medical services (EMS) provides out-of-hospital care to patients with life-threatening conditions, but the long-term outcomes of EMS patients are unknown. We seek to determine the long-term mortality of EMS patients in Denmark.

Methods

We analyzed linked EMS, hospital, and vital status data from 3 of 5 geographic regions in Denmark. We included events from July 1, 2011, to December 31, 2012. We classified EMS events according to primary dispatch category (unconsciousness/cardiac arrest, accidents/trauma, chest pain, dyspnea, neurologic symptoms, and other EMS patients). The primary outcome was 1-year mortality adjusted for age, sex, and Charlson comorbidity index.

Results

Among 142,125 EMS events, primary dispatch categories were unconsciousness or cardiac arrest 5,563 (3.9%), accidents or trauma 40,784 (28.7%), chest pain 20,945 (14.7%), dyspnea 9,607 (6.8%), neurologic symptoms 17,804 (12.5%), and other EMS patients 47,422 (33.4%). One-year mortality rates were unconscious or cardiac arrest 54.7% (95% confidence interval [CI] 53.4% to 56.1%), accidents or trauma 7.8 (95% CI 7.5% to 8.1%), chest pain 8.5% (95% CI 8.1% to 9.0%), dyspnea 27.7% (95% CI 26.7% to 28.7%), neurologic symptoms 14.1% (95% CI 13.6% to 14.7%), and other EMS patients 11.1% (95% CI 10.8% to 11.4%). Compared with other EMS conditions, adjusted 1-year mortality was higher in unconsciousness or cardiac arrest (risk ratio [RR] 2.6; 95% CI 2.5 to 2.7), dyspnea (RR 1.5; 95% CI 1.4 to 1.5), and in neurologic symptoms (RR 1.1; 95% CI 1.0 to 1.1), but lower in chest pain (RR 0.6; 95% CI 0.6 to 0.7) and accidents or trauma (RR 0.8; 95% CI 0.8 to 0.8).

Conclusion

EMS patients with unconsciousness or cardiac arrest, dyspnea, and neurologic symptoms are at highest risk of long-term mortality. Our results suggest a potential for outcome improvement in these patients.

Introduction

Emergency medical services (EMS) was born from the goal of optimizing trauma and cardiac arrest care.1 Systematic clinical approaches have reduced mortality in these patients.2, 3 EMS cares for many other patient groups, and only limited data describe the overall or condition-specific long-term mortality rates of EMS patients. Thus, high-risk groups in need of optimized care may be overlooked.

Editor’s Capsule Summary

What is already known on this topic

Emergency medical services (EMS) patients include those with life-threatening conditions such as cardiac arrest and major trauma.

What question this study addressed

What is the long-term mortality of EMS patients who present with different chief complaints?

What this study adds to our knowledge

In this study of 142,125 EMS events in Denmark, 30-day and 1-year mortality was highest for cardiac arrests or unconsciousness (49% and 55%, respectively), dyspnea (12% and 28%, respectively), and neurologic emergencies (6% and 14%, respectively).

How this is relevant to clinical practice

These results highlight high-mortality conditions that deserve EMS focus and research in regard to how more effective treatment might be achieved.

To clarify how EMS management affects the care of patients, it is crucial to understand condition-specific short- and long-term mortality of these patients, as well as the confounding effect of age, sex, and comorbidities. Differences in long-term mortality may indicate opportunities for intensified or specialized initial acute care.

This study aimed to determine long-term mortality rates among patients receiving EMS care in Denmark.

Section snippets

Study Design

We used linked EMS, hospital, and vital status data from 3 geographic regions in Denmark. The Danish Data Protection Agency and the National Board of Health approved this study.

Setting

The Capital Region of Denmark, the Central Denmark Region, and the Region of Southern Denmark are populated by 4.2 million inhabitants, representing approximately 75% of the total Danish population.4 The Danish National Health Service provides universal tax-supported health care, guaranteeing unfettered access to general

Characteristics of Study Subjects

Of 271,642 ambulance dispatches, we identified and included 142,125 valid unique first patient contacts (Figure 1). In total, 5,563 patients (3.9%) were unconscious or had cardiac arrest, 40,784 (28.7%) had been subject to accident or trauma, 20,945 (14.7%) experienced chest pain, 9,607 (6.8%) experienced dyspnea, 17,804 (12.5%) experienced neurologic symptoms, and 47,422 (33.4%) were other EMS patients. Table 1 contains baseline characteristics. In general, EMS patients subject to accidents or

Limitations

In a number of EMS contacts, a dispatch code was either missing or invalid. Approximately 30% of these also lacked time stamps for ambulance dispatch, arrival at scene, etc, and were probably double registrations (ie, a registration begun but not completed and subsequently reentered with the correct information). It is unlikely that these exclusions have biased our findings because dispatch category was registered prospectively and any errors were unlikely to be related to the outcome of the

Discussion

This study demonstrates that patients with unconsciousness or cardiac arrest, dyspnea, and neurologic symptoms exhibit higher mortality rates than other EMS patients. We also found that confounding effects of age, sex, and comorbidities did not explain the higher mortality in these patients. Our unique study takes advantage of a large population with free and unlimited access to EMS, as well as comprehensive linked EMS, hospital, and vital status data.

Comparable studies examining mortality

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    Please see page 367 for the Editor’s Capsule Summary of this article.

    Supervising editor: Henry E. Wang, MD, MS

    Author contributions: MTB, CJT, SPJ, EFC, and MSA designed the study. JNS, SBJ, and MSA were responsible for data collection. MTB and MSA conducted data management and data analysis. MTB drafted the article, and CJT, JNS, SBJ, SPJ, EFC, and MSA revised it. MTB takes responsibility for the paper as a whole.

    All authors attest to meeting the four ICMJE.org authorship criteria: (1) Substantial contributions to the conception or design of the work; or the acquisition, analysis, or interpretation of data for the work; AND (2) Drafting the work or revising it critically for important intellectual content; AND (3) Final approval of the version to be published; AND (4) Agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

    Funding and support: By Annals policy, all authors are required to disclose any and all commercial, financial, and other relationships in any way related to the subject of this article as per ICMJE conflict of interest guidelines (see www.icmje.org). Dr. Bøtker receives lecture fees from USabcd A/S and royalties for electronic learning published by USabcd.org. The Prehospital Emergency Medical Services, Central Denmark Region, and the Health Research fund of the Central Denmark Region funded the study. TrygFonden, an independent foundation, funded original data extraction.

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