INTRODUCTION
The number of older patients visiting the emergency department (ED) is increasing rapidly.
1,2) In the United States, approximately 20% of the population visits the ED each year, with patients aged 65 years or older accounting for over 45% of visits.
3) According to data from the National Emergency Department Information System in Korea, the proportion of older adults aged 60 years or more increased from 22% in 2014 to 28% in 2018.
4) Older patients visiting the ED have higher rates of hospitalization, mortality, and repeat visits than those in younger patients.
5-7) This is because older patients are more likely to have an ambiguous presentation with multiple comorbidities, as well as complex problems such as polypharmacy and frailty.
5-8) Previous studies have reported on early death after discharge from the ED in older adults, with mortality rates of 0.4% within 30 days and 4.1% within 90 days.
9,10)
Several studies have identified common causes of death after discharge from the ED, including neoplasm, ischemic heart disease, cerebrovascular disease, and respiratory disease.
11,12) In addition, studies confirming the diagnosis of ED discharge as a risk factor for early death within 7 days after discharge have been reported.
13,14) In a study using US Medicare claims data, patients discharged from the ED with altered mentality, dyspnea, or fatigue had higher risks of death within 7 days.
13) In another study analyzing the administrative data of 12 EDs in California, high mortality rates were observed within 7 days of ED discharge for diagnoses of noninfectious lung disease, renal disease, and ischemic heart disease.
14) However, these studies were performed in adults and the causes and risk factors of early death after ED discharge in older populations are not well known.
The purpose of this study was to identify the causes of death in older patients who died after ED discharge and to determine the risk of early death according to the ED discharge diagnoses.
DISCUSSION
In this study, the rate of 1-week ED death was 0.5%. The top five discharge diagnoses associated with an increased risk of short-term mortality were hypotension and vascular disease, neoplasm, CAD, symptom of dyspnea, and respiratory disease. The most common causes of death were neoplasm (14.8%), senility (13.8%), cerebrovascular disease (11.7%), injury and poisoning (11.4%), and CAD (9.8%).
Gabayan et al reported a rate of 1-week ED death of 0.05% among 475,829 patients from 12 hospitals in California discharged from the ED.
14) Obermeyer et al.
13) studied 10,093,678 patients included in a 20% sample of the US Medicare population, reporting a 1-week mortality rate of 0.12%. The mean ages of the subjects included in these two studies were 47 and 62 years, respectively. Our study of older patients with a median age of 75 showed a 1-weak ED mortality rate of 0.5%.
Multivariate analysis of the association between ED discharge diagnosis and 1-weak ED death showed the highest risk for hypotension and vascular disease (aHR=5.11). These results were not reported in previous studies and indicate that older patients with hypotension or vascular disease should be more seriously considered for hospitalization. In addition, as hypotension itself may be a secondary change rather than a primary diagnosis, additional evaluation should be considered. Neoplasm had an increased risk (aHR=4.89), consistent with previous studies. Gabayan et al.
14) reported an odds ratio (OR) of 3.7 for 1-week ED death due to neoplasm in patients with a mean age of 47 years. The median age of the patients in our study was 75 years and the aHR for short-term ED death in patients with neoplasm was 4.89. Rivera et al.
15) analyzed cancer patients who visited the ED, reporting that complications such as pneumonia, septicemia, heart failure, and ileus were associated with hospitalization. Therefore, hospitalization should be considered for patients with neoplasms even if they have the same disease. The risk of 1-week ED death in CAD patients increased by 3.83-fold, similar to previous studies.
13,16) Gabayan et al.
14) reported an OR of CAD of 3.8. More careful observation is needed for patients discharged from the ED with CAD diagnosis or related symptom such as chest pain. In the present study, increased risks were observed for patients with dyspnea (aHR=3.41) and lung diseases (aHR=2.25) such as chronic obstructive pulmonary disease (COPD), asthma, pneumonia, and pneumonitis. Gabayan et al.
14) reported a 7-fold risk of 1-week ED death in patients with noninfectious lung disease such as pleurisy and pneumothorax, 3-fold risk in pneumonia patients, and a 1.7-fold risk in patients with COPD patients. Obermeyer et al.
13) reported a 3-fold risk of early death in patients discharged from the ED with a diagnosis of dyspnea. Overall, patients with an ED discharge diagnosis of lung disease or dyspnea had an increased risk of early death and our study showed similar trends in older patients. In a previous study, 5.2% of patients visited ED with dyspnea, and 30% of whom were discharged.
17) Considering the relatively large number of patients with dyspnea discharge, sufficient evaluation and risk stratification is needed.
Gunnarsdottir and Rafnsson
12) analyzed 19,259 patients discharged from the ED and found that 63 patients died within 8 days. The causes of death were neoplasm (27%), CAD (20.6%), cerebrovascular disease (19%), and respiratory disease (9.5%). Rafnsson and Gunnarsdottir
11) reported that 156 of 228,097 patients died within 8 days after ED discharge. The causes of death were CAD (24.4%), neoplasm (15.4%), and cerebrovascular disease (12.2%). In the study by Gabayan et al.
14) of 357 patients who died within 7 days after ED discharge, the common causes of death were neoplasm (19.6%), CAD (17.3%), and non-atherosclerotic heart disease (11.3%). These results are similar to our findings that neoplasm, cerebrovascular disease, and CAD were the main causes of short-term death. Of note is the increasing rate of cerebrovascular disease and CAD-related mortality in Korea.
18) In our study, senility was the second leading cause of death, likely because many physicians may indicate unclear diagnoses as the cause of death.
19)
Subgroup analysis showed increased aHR for hypotension and vascular disease as the ED level increased. Similar to of total included patients, symptoms of dyspnea, as well as neoplasm and CAD accounted for the highest risks of 1-week ED death in all three groups. The aHRs for these risk factors were highest in local emergency medical facilities compared to those in the other two subgroups. In particular, hypotension and vascular disease had the highest aHR of 9.17.
This study has several strengths. This nationwide population-based study focused on older patients had a large sample size including both men and women. Understanding these patients will be helpful because the number of older patients visiting EDs is increasing. However, this study has some limitations that should be considered when interpreting the results. First, we could not distinguish between patients with hopeless discharge and patients who died unexpectedly. For example, our data did not contain information on do-not-resuscitate orders. Second, the cause of death and discharge diagnoses were recorded by clinicians and could have been inaccurate. However, considering the large number of the study population, the overall pattern of outcomes could be confirmed. Lastly, the database used in this study was sample data, which might have different characteristics from those of the entire older population. However, as the study included 550,000 individuals, the standard error would be minimal.
In conclusion, the rate of death within 1 week among older patients discharged from the ED was 0.5%. Clinicians should consider the increased risk for short-term mortality among older patients with ED discharge diagnoses of neoplasm, CAD, and respiratory disease. Neoplasm was the leading cause of short-term death in this population.