Serious Cardiac Outcomes and Physician Estimation of Risk in Emergency Department Patients With Presyncope Versus Syncope

Study objective Previous research suggests that the short-term incidence of adverse events is similar in emergency department (ED) patients with presyncope and syncope. However, admission rates for presyncope are lower, which could imply clinicians underestimate its risk. We sought to compare physician risk estimates and the 30-day rate of serious cardiac outcomes between patients with syncope and presyncope. Methods We conducted a secondary analysis of a prospective, observational, multicenter study of patients aged ≥40 years presenting to ED with presyncope or syncope. Patients with serious ED diagnoses were excluded. Descriptive statistics and multivariable regression analyses were used to compare the physician-estimated risk, ED disposition, and 30-day rate of adverse outcomes. Results Of the 1,263 patients analyzed, 721 (57%) had syncope and 542 (43%) had presyncope. Baseline characteristics were similar between groups. At 30 days, 34 (4.7%) syncope patients and 28 (5.2%) presyncope patients experienced a serious cardiac outcome; logistic regression showed no difference in the odds (odds ratio 1.13; 95% confidence interval 0.66 to 1.79) of serious cardiac outcomes between syncope and presyncope patients. The mean physician-estimated risk of serious cardiac outcomes was 7.6% in syncope, versus 5.3% in presyncope (risk difference 2.3% [0.89%, 3.7%]); this difference remained significant after adjustment for clinical characteristics. Admission rate was lower in presyncope, 38.2% versus 49.5% (risk difference 11.3% [1.2%, 21.5%]). Conclusion Patients with unexplained presyncope and syncope had similar rates of 30-day serious cardiac outcomes after ED visit. Patients with presyncope were less likely to be admitted and had a lower mean physician-estimated risk of adverse outcomes.