Incidence and mortality rates of syncope in the United States

Syncope is a common cause of hospitalization in the US. The main objective of this study is to determine the incidence and mortality rates when patients are admitted with a principle diagnosis of syncope.

An observational cross-sectional study included patients with the principle diagnosis of syncope identified from the National Inpatient Sample database for the years 2000-2005. Incidence rate of syncope was adjusted according to the US Census data. In-hospital mortality and its predictors were identified by a logistic regression analysis, and Cochran-Armitage test was used for trend analysis.

After data cleansing, 305,932 patients were included in the analysis. Adjusted incidence rate of syncope varied between 0.80 and 0.93 per 1000 person-years and was unchanged over the years included in the analysis. Overall mortality rate is 0.28%, a trend that has not changed over the years (P=0.07). The odds ratio (OR) of death increased with age, becoming more prominent after age 40 years. Hospital mortality is higher in men (OR 1.49; 95% confidence interval [CI], 1.30-1.71) and in patients with higher comorbidity index (OR 1.39; 95% CI, 1.20-1.62) for moderate, and (OR 4.14; 95% CI, 3.05-5.61) for severe comorbidity index. The median cost of hospitalization is $8579, which increased by 3- to 11-fold if patients had a cardiac pacemaker or implantable cardioverter-defibrillator.

Syncope remains a common cause of hospital admission. The hospital mortality rate for syncope is low. A better definition and a nationally implemented care path for syncope diagnosis could provide a substantial cost savings.