Risk Factors and Causes of Short-Term Mortality after Emergency Department Discharge in Older Patients: Using Nationwide Health Insurance Claims Data.

Background: The purpose of this study was to identify the risk factors and causes of short-term mortality after emergency department (ED) discharge in older patients. Methods: This population-based cohort study used nationwide health insurance claims data in Korea from 2008 to 2014. The causes of death and diagnoses of patients who died within 1 week after discharge from EDs (1-week ED death) were obtained. The risk factors for 1-week ED death were calculated using Cox proportional hazard regression analyses. Results: The rate of 1-week ED death was 0.5% among 133,251 individuals aged >= 65 years discharged from EDs. In multivariate analysis, the top five ED discharge diagnoses associated with an increased risk of 1-week ED death were hypotension and vascular disease (adjusted hazard ratio [aHR]=5.11; 95% confidence interval [CI], 3.03-8.63), neoplasm (aHR=4.89; 95% CI, 3.77-6.35), coronary artery disease (aHR=3.83; 95% CI, 2.73-5.39), dyspnea (aHR=3.41; 95% CI, 2.48-4.68), and respiratory disease (aHR=2.25; 95% CI, 1.73-2.92). The most common causes of 1-week ED death were neoplasm (14.8%), senility (13.8%), and cerebrovascular disease (11.7%). Conclusion: Neoplasm, coronary artery disease, and respiratory disease were the discharge diagnoses associated with an increased risk of short-term mortality after ED discharge. Neoplasm was the leading cause of short-term mortality after ED discharge in older patients.