Clinical question: What is the prevalence of pulmonary embolism (PE) in patients presenting to the ED with syncope?
Background: PE is commonly accepted as a “can’t miss” diagnosis in the work-up of syncope. However, the actual prevalence of PE in patients presenting with syncope is inconsistently characterized.
Study design: Retrospective, observational study.
Setting: Canada, Denmark, Italy, and the United States, from January 2010 to September 2016.
Synopsis: Longitudinal administrative databases were used to identify patients with ICD codes for syncope at discharge from the ED or hospital. Those with an ICD code for PE were included to calculate the prevalence of PE in this population (primary outcome).
The prevalence of PE in all patients ranged from 0.06% (95% confidence interval, 0.05%-0.06%) to 0.55% (95% CI, 0.50%-0.61%); and in hospitalized patients from 0.15% (95% CI, 0.14%-0.16%) to 2.10% (95% CI, 1.84%-2.39%). This is a much lower than the estimated 17.3% prevalence of PE in patients presenting with syncope estimated by the PESIT study published in the New England Journal of Medicine in 2016. Further definitive research is needed to better characterize prevalence rates.
Limitations of this study include the potential for information bias: The inclusion criteria of patients coded for syncope at discharge likely omits some patients who initially presented with syncope but were coded for a primary diagnosis that caused syncope.
Bottom line: PE in patients presenting to the ED with syncope may be rare.
Citation: Costantino G et al. Prevalence of pulmonary embolism in patients with syncope. JAMA. 2018;178(3):356-62.
Dr. Roy is a hospitalist at Beth Israel Deaconess Medical Center, and instructor in medicine, Harvard Medical School, Boston.