Outcomes in Adults With Acute Pulmonary Embolism Who Are Discharged From Emergency Departments: The Cardiovascular Research Network Venous Thromboembolism Study

Patients with acute pulmonary embolism (PE) have conventionally been hospitalized for their initial management and initiation of anticoagulant treatment.¹ A clinical trial² found that patients with PE who were considered at low risk by the PE Severity Index could be safely treated as outpatients.³ However, it is unclear how often outpatient PE treatment occurs in real-world settings or whether outcomes are as favorable as in the clinical trial. Our study describes the short-term rates of death and hospital admission for patients with acute PE who were discharged from emergency department (ED) settings.

We obtained data from the Cardiovascular Research Network Venous Thromboembolism (CVRN VTE) study, a collaboration of 4 integrated health care delivery systems (Kaiser Permanente Northern California, Kaiser Permanente Colorado, Marshfield Clinic Research Foundation, and Geisinger Health System) and identified all adults (aged ≥21 years) with a primary International Classification of Diseases, Ninth Revision (ICD-9) diagnosis of pulmonary embolism (ICD-9 code 415.1x) during an ED visit from January 1, 2004, through December 31, 2010. We restricted the analysis to patients who were discharged from EDs with an anticoagulant prescription within 7 days. Exclusion criteria were less than 12 months of continuous pharmacy benefits, prior venous thromboembolism diagnoses, or outpatient anticoagulant prescriptions within 4 years. Anticoagulants included warfarin sodium, low-molecular-weight heparins, and fondaparinux sodium (because target-specific oral anticoagulants were not yet approved for use in PE). Data regarding patient demographics, medication use, and ICD-9 diagnoses were obtained from electronic databases. Primary outcomes for this analysis included hospital admission within 30 days and death within 90 days of the index ED encounter. We used descriptive statistics to report outcome rates. This study was approved by institutional review boards of the participating sites (Kaiser Permanente Northern California, Kaiser Permanente Colorado, Marshfield Clinic Research Foundation, and Geisinger Health System) and a waiver of informed consent was obtained owing to the nature of the study.

Of 5927 patients with a primary diagnosis of PE, 494 (8.3%) were discharged from ED settings. The proportion of ED-discharged patients with PE increased over time, from 37 of 657 (5.6%) in 2004 to 110 of 994 (11.1%) in 2010 (P <.001 for trend). Characteristics of ED-discharged patients are presented in the Table.⁴ Within 30 days of discharge from the ED, 92 of the 494 patients with PE (18.6%) had another visit to the ED and 39 (7.9%) were hospitalized. Eleven patients (2.2%) had a primary diagnosis of hemorrhage during a subsequent visit to the ED or hospital within 30 days. Mortality was low—none died within 7 days and 2 died (0.4%) within 90 days.

Patients with acute PE who were discharged from ED settings in 4 geographically diverse health care delivery systems had mortality rates comparable with outcomes observed in a clinical trial³ that examined outpatient management of PE. Although still representing relatively few patients with PE, the proportion of discharges from ED settings nearly doubled during the 7-year study. Shifting appropriate patients to outpatient treatment may have benefits in terms of improved quality of life, enhanced physical and social functioning, and reduced costs of medical care.⁵ We note that at least 23.4% of the patients in our study would not have been eligible for outpatient treatment in the clinical trial because they had a higher PE Severity Index risk class.³

Limitations to our study include identification of PEs using ICD-9 codes and pharmacy data alone, the lack of detailed physiologic data required to calculate a full PE severity risk class, and the inability to determine specific reasons for patient disposition plans.

Our study confirms that selected patients with PE can be treated as outpatients with favorable short-term outcomes.

Corresponding Author: Margaret C. Fang, MD, MPH, Division of Hospital Medicine, University of California, San Francisco, 533 Parnassus Ave, PO Box 0131, San Francisco, CA 94143 (mfang@medicine.ucsf.edu).

Published Online: April 20, 2015. doi:10.1001/jamainternmed.2015.0936.

Author Contributions: Dr Fang had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Study concept and design: Fang, Go.

Acquisition, analysis, or interpretation of data: All authors.

Drafting of the manuscript: Fang, Witt.

Critical revision of the manuscript for important intellectual content: Fan, Sung, Witt, Yale, Steinhubl, Go.

Statistical analysis: Fang, Fan.

Obtained funding: Fang, Go.

Administrative, technical, or material support: Sung, Witt, Yale, Go.

Study supervision: Go.

Conflict of Interest Disclosures: Dr Go reports receiving a research grant from CSL Behring. No other disclosures were reported.

Funding/Support: This study was funded by grant R01HL103820 from the National Heart, Lung, and Blood Institute of the National Institutes of Health (Dr Fang).

Role of the Funder/Sponsor: The funding source had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

Additional Contributions: John R. Schmelzer, PhD, Marshfield Clinic Research Foundation, contributed to the initial conception and design of the study and acquisition and interpretation of the data and provided critical revisions to the final manuscript. He was not financially compensated.