Health policy and clinical practice/original research
Prolonged Emergency Department Stays of Non–ST-Segment-Elevation Myocardial Infarction Patients Are Associated With Worse Adherence to the American College of Cardiology/American Heart Association Guidelines for Management and Increased Adverse Events

https://doi.org/10.1016/j.annemergmed.2007.03.033Get rights and content

Study objective

We evaluate the association of emergency department (ED) length of stay with use of guideline-recommended therapies for acute treatments and clinical outcomes. Prolonged ED stays often reflect ED crowding or limited hospital capacity. We hypothesized that patients with non–ST-segment-elevation myocardial infarction who have ED stays of greater than 8 hours may have lower quality of care and worse outcomes.

Methods

Using a secondary analysis of data from an observational registry (Can Rapid Risk Stratification of Unstable Angina Patients Suppress ADverse Outcomes with Early Implementation of the ACC/AHA Guidelines, CRUSADE), we compared rates of use of 5 individual acute (<24 hours) guideline-recommended therapies in patients with non–ST-segment-elevation myocardial infarction according to ED length of stay. Patients were grouped by length of stay (short [<4 hours], average [4 to 8 hours], or long [>8 hours]). Multivariable analyses were used to determine independent association of ED length of stay with acute medications and inhospital outcomes (death and myocardial infarction).

Results

This analysis included 42,780 patients with non–ST-segment-elevation myocardial infarction. The median ED length of stay was 4.3 hours (25th to 75th percentile 2.9, 6.3); 15% of patients stayed longer than 8 hours. Patients who had long ED stays were more likely to be women and nonwhite and less likely to have health maintenance organization or private insurance. After adjustment, patients with long ED stays less often received guideline-recommended acute myocardial infarction therapies. Although risk-adjusted inhospital mortality rates were similar among groups, the rate of recurrent myocardial infarction increased among patients with long ED stays (odds ratio 1.23; 95% confidence interval 1.01 to 1.48) compared with those with average ED length of stay.

Conclusion

For patients with non–ST-segment-elevation myocardial infarction, long ED stays were associated with decreased use of guideline-recommended therapies and a higher risk of recurrent myocardial infarction. However, there was no observed difference in mortality. Factors associated with prolonged ED length of stay should be evaluated to optimize treatments and outcomes of patients with non–ST-segment-elevation myocardial infarction.

Introduction

Emergency department (ED) and hospital crowding have become an increasing problem in US hospitals. The Institute of Medicine report evaluating emergency care services has identified ED crowding, ambulance diversion, and boarding of admitted patients in the ED as areas of significant concern that affect patient care.1 Patients with a diagnosis of unstable angina or non–ST-segment-elevation myocardial infarction account for a large number of ED visits each year.2, 3, 4 Although patients with non–ST-segment-elevation myocardial infarction are typically admitted promptly after diagnosis, under conditions of ED or hospital crowding, these patients may have prolonged ED stays as they await transfer to an inpatient unit or to the catheterization laboratory. However, during this period, they continue to require ongoing evaluation and treatment. Under such conditions, there is the potential that patients will be less closely monitored or treated less aggressively as ED staff attention is diverted to the triage and treatment of new acute ED patients. Although previous studies have suggested an association between prolonged ED stays and increased morbidity in an undifferentiated patient population, there is no information about whether this association pertains to cardiovascular patients.5, 6

We evaluated the association between ED length of stay, guideline adherence to 5 individual acute medications, and clinical outcomes in a contemporary population of patients with non–ST-segment-elevation myocardial infarction from the Can Rapid Risk Stratification of Unstable Angina Patients Suppress ADverse Outcomes with Early Implementation of the ACC/AHA Guidelines (CRUSADE) national quality improvement initiative. Our goals were to determine the variability in ED length of stay for patients with non–ST-segment-elevation myocardial infarction and to describe the association of ED length of stay with the use of evidence-based therapies and inhospital outcomes.

Section snippets

Study Design

This is a secondary analysis of a subset of data from an ongoing voluntary observation registry. CRUSADE is an ongoing, voluntary, observational data collection and quality improvement initiative. The CRUSADE initiative is designed to track guideline adherence, provide feedback about performance, and develop quality improvement tools to improve adherence to guideline recommendations. Data are collected anonymously during the initial hospitalization, and because no patient identifiers are

Results

Of 56,104 CRUSADE patients who were first evaluated in the ED and had arrival ED times, 42,780 (76 %) met criteria and were included in this analysis. A total of 13,324 patients were excluded: 3,407 patients had negative cardiac biomarker results, 1,618 patients were transferred from another hospital, 7,921 underwent catheterization within 12 hours of arrival, 83 patients died within 12 hours, and 295 had cardiogenic shock within 24 hours of arrival.

The median ED stay for patients with

Limitations

This study has several limitations. We did not examine location where medical therapies were given (ED versus cardiac care unit versus cardiac floor), nor could we evaluate the time to treatment for individual medications to understand whether medications were actually administered in the ED. We therefore cannot attribute the lack of administration of acute medications specifically to ED-based health care providers or system failures. The inability to perform this analysis was due to the

Discussion

As our health care system struggles with the ever-increasing burden of crowding, ED boarding of admitted patients is becoming a cause for concern.1 Because this problem spans hospital services, the evaluation of long length of ED stay as a part of overall patient care is important. In this large contemporary high-risk group of patients with non–ST-segment-elevation myocardial infarction, we demonstrate an association between prolonged ED stays and lack of adherence with each of 5 acute care

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    Supervising editor: Judd E. Hollander, MD

    Author contributions: DBD, MTR, WBG, EMO, and EDP conceived and designed the study. AYC analyzed and interpreted the data. DBD drafted the article. All authors revised the article for important intellectual content and approved the final article. DBD takes responsibility for the paper as a whole.

    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, that might create any potential conflict of interest. See the Manuscript Submission Agreement in this issue for examples of specific conflicts covered by this statement. CRUSADE is funded by Schering-Plough Corporation. Birstol-Myers Squibb/Sanofi Pharmaceuticals Partnership provides additional funding support. Millennium Pharmaceuticals, Inc. also provided funding for this work.

    Available online June 20, 2007.

    Reprints not available from the authors.

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