Cardiology/original researchProspective Validation of the San Francisco Syncope Rule to Predict Patients With Serious Outcomes
Introduction
Approximately a quarter of the population will experience syncope (fainting) during their lifetime. Frequently, these patients will present to emergency departments (EDs), accounting for 1% to 2% of all ED visits and hospital admissions.1, 2, 3, 4, 5 Syncope occurs in the old and the young; it can be infrequent or recurrent; and although usually a benign symptom, it is occasionally associated with significant morbidity, such as arrhythmia, myocardial infarction, pulmonary embolism, occult hemorrhage, or death.6, 7, 8, 9 As a result, syncope is often referred to a “low-risk/high-stakes” symptom,10 with physicians admitting many patients who they believe are at low risk because of the high stakes if something adverse happens.
It is estimated that the cost of admission because of syncope in the United States may be as high as $2 billion annually.11 Specialty guidelines have tended to be conservative on admission recommendations, often citing a lack of clear evidence or criteria, and it is unclear if followed whether these recommendations would lead to an increase or decrease in admissions.12, 13, 14, 15 Furthermore, it has been demonstrated that many patients who are admitted receive little or no diagnostic evaluation as part of inpatient care.16, 17 This inefficient use of expensive hospitalization has resulted in a need for a more cost effective approach.18, 19, 20, 21, 22, 23, 24
We believe efficiencies can be realized through improved risk stratification and started a multiphase study to address this important problem. Using strict methodologic criteria for decision rule development, we first derived the San Francisco Syncope Rule, as illustrated in the Figure. We believe this highly sensitive clinical decision rule can augment physician judgment and allow physicians to rationally decide which patients with syncope need admission.4, 25 The purpose of this study is to validate the decision rule in a prospective cohort of consecutive ED patients by determining whether it can predict short-term serious outcomes not determined during the initial ED evaluation.
Section snippets
Setting
This prospective cohort study was conducted at the ED of the University of California at San Francisco, a large university teaching hospital. It received approval from the institution’s Committee on Human Research. Patients presenting with acute syncope or near syncope for their ED visit were considered for the study. To identify patients, we informed physicians that we were doing the study and used an electronic tracking system to identify all possible patients with a symptom of syncope.26 As
Results
During the study period, 760 patients had 791 visits for syncope, representing 1.2% of all ED visits. Of the 791 visits, physicians prospectively completed forms for 767 of the visits, and direct follow-up was completed on 752 visits. We were unable to directly contact 39 patients (5%) but found through a check of local hospitals and the Social Security Death Index that there were no unknown local admissions or deaths among these 39 patients.
The average age in the cohort was 61 years, 54% were
Limitations
This study did have some challenges and limitations. Despite our study’s size, all our patients came from a single hospital, although the demographics and admission rates of our patients appear to parallel those reported from other centers in the United States and Europe.27, 28, 29, 30 Also, decision rules have traditionally focused on areas in which the outcome measure is discrete, clearly defined, and easily measured, such as fracture versus no fracture on radiograph.31 For the purpose of a
Discussion
In this prospective validation study of consecutive ED patients with syncope, we have demonstrated that patients with undeclared serious outcomes can be accurately predicted by our previously derived clinical decision rule. If the decision rule were used to improve risk stratification and augment physician judgment, it could save millions of dollars by improving the use of hospital admission for patients with syncope.11
Evidence demonstrates that many admissions for syncope are inefficient. In
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2020, Canadian Journal of Cardiology
Supervising editor: Judd E. Hollander, MD
Author contributions: JQ, IS, and GW conceived and designed the trial. JQ, DM, and MK supervised the conduct of the trial and data collection and provided database management and quality control. JQ, IS, MK, and GW contributed to the statistical analysis with advice, with JQ and IS doing the primary analysis. JQ drafted the manuscript, with all authors contributing significantly to its revisions. JQ takes responsibility for the paper as a whole.
Funding and support: JQ is funded through a career development grant from the National Institutes of Health, K23, AR002137-050.
Reprints not available from the authors.