Discussion
This study presents data on mortality and readmission among different chief complaints presented to the ED. We found that ALOC, dyspnea and GI bleeding had the highest 30-day mortality, and fever/infection, dyspnea, and nausea, vomiting and diarrhea had the highest 30-day readmission. Dyspnea was very frequent and associated with both high mortality and readmission compared with other chief complaints. Chest pain was found to be relatively frequent and had the lowest mortality. Second, we looked at discharge diagnoses among the 10 chief complaints with the highest 30-day mortality and found that each chief complaint had various discharge diagnoses across the ICD-10 chapters, with the unspecific R-diagnoses frequently represented.
In the present study, the overall 30-day mortality was 3% and differed significantly among the chief complaints, which is in line with Nielsen et al10 in a similar study including medical ED patients. Moreover, we found an overall 30-day readmission of 6.5%, which also differed significantly among the chief complaints. Previous studies have mainly focused on readmission based on discharge diagnosis14 15; however, few studies have described short-term readmission/revisit in the ED,16 but the definitions of “readmission” and “revisit” differ and are often used interchangeably, making comparison difficult. Furthermore, organization of the health system also plays a major role in terms of readmission.
ALOC had the highest 30-day mortality (8.4%, OR=2.0). This chief complaint is not included in previous studies comparing ED chief complaints; however, this finding is supported by Völk et al, who found an in-hospital mortality of 10% among patients presenting to the ED with ALOC. The higher mortality found by Völk et al17 may be explained by only including unknown reasons for ALOC. In the present study, ALOC was not one of the most common chief complaints and only represented 2.6% of the study population. In addition, it was not associated with a significantly higher readmission. ALOC is acknowledged as an unspecific but critical condition associated with various causes, for example, intoxication, trauma and vascular emergencies.18 Correspondingly we found a diverse distribution of discharge diagnoses among patients with ALOC; however, the unspecific R-diagnoses were most used (21.5%).
Unwell is also an unspecific complaint, and interestingly we found a relatively high mortality (6.0%) in this group as well, but not significantly higher after adjusting for age and gender. Like ALOC, unwell had a diverse distribution of discharge diagnoses, with 30.2% being unspecific R-diagnoses. These findings indicate that unspecific complaints are difficult to diagnose and have a high mortality, corresponding to the findings by Nemec et al19 in an ED study investigating unspecific complaints. Thus, further research and development of risk stratification tools is needed to identify patients at high risk of presenting with these unspecific complaints.
Dyspnea had the second highest 30-day mortality (8.0%, OR=2.1) in the present study. Furthermore, it was very prevalent (8.4%) and had significantly higher 30-day readmission (11.2%, OR=1.7). Patients presenting to the ED with dyspnea have previously been found to have high mortality compared with other chief complaints in the ED, both long term and short term6–10; however, the high 30-day readmission is a new finding. This suggests that patients with dyspnea in the ED are very frequent and at higher risk of adverse outcomes, calling for increased awareness. Moreover, they represent a heterogenous group with various diagnoses and needs and thus remain a challenge to the ED physician.20 21 Further studies are needed to evaluate the diagnostic workup and initial treatment and to identify prognostic factors. Moreover, standardized algorithm and risk stratification tool are advisable to quickly identify patients with dyspnea at high risk.22
GI bleeding was the “surgical complaint” found to have the highest 30-day mortality (6.7%, OR=1.7). Likewise, previous studies have reported high mortality among this patient group, with an in-hospital mortality of 7% to 8%.23 Furthermore, GI bleeding had the strongest association with a specific ICD-10 main chapter (61.2%, K - diseases of the digestive tract). Acute management of GI bleeding is very important and the challenge in the ED is to determine if intervention is needed, for example, endoscopy, transfusion and surgery.24
In the present study, we found chest pain to be less prevalent (5.7%) and with a surprisingly low mortality compared with other European ED studies.6–10 However, the low mortality corresponds to what was found in a study by Nielsen et al10 from another Danish ED. These findings can be explained by a common practice in Denmark, where all patients with STEMI and cardiac arrest are referred directly to the cardiac catheterization laboratory from the prehospital area, thereby bypassing the ED. This finding also indicates that prehospital visitation of patients with chest pain is effective.
Fever/infection, nausea, vomiting and diarrhea, and abdominal symptoms, together with dyspnea, had the highest 30-day readmission, all at more than 10%. Whether some of these readmissions were preventable is unknown; however, it is known that preventable factors such as too early discharge can lead to acute readmissions.25 Identifying patients at high risk of readmission is important to determine which patients can be sent home safely and which cannot. This could potentially increase patient flow, without further risk to the patient.
Among the 10 chief complaints with the highest 30-day mortality, we found that they all had a wide distribution of discharge diagnoses. This suggests that chief complaint offers information independent of diagnosis and is also available in a timely manner to the ED physician compared with a final diagnosis, which is one of the reasons why symptom-based research is essential to emergency medicine.
The fact that chief complaint is associated with multiple final diagnoses also emphasizes the importance of not thinking too narrow in terms of differential diagnoses, which underlines the challenging essence of emergency medicine: to initiate acute treatment and diagnostic workup to “convert” a patient’s symptoms to a correct diagnosis, to assure the best treatment.
Furthermore, we found that unspecific diagnoses (majorly R-diagnoses and less frequent Z-diagnoses) were often used, which means that many ED patients leave the hospital without a specific diagnosis. This may be explained by the patients being stable and discharged to further diagnostic workup electively or at the general practitioner. Another contributing factor could be the patients getting well spontaneously and therefore discharged without specific diagnosis. However, the large proportion of patients without organ-specific or cause-specific diagnosis is inappropriate and underlines the need to improve the diagnostic process. More research is needed to understand the link between discharge diagnoses and chief complaints.
The 1-year follow-up revealed that ALOC and dyspnea stood out with a mortality of 24% and 23.4% (both with adjusted OR of 2.1). These are alarming numbers, but are not new. A Danish study of emergency medical services patients also found impaired consciousness and dyspnea to have the highest mortality, with a 1-year mortality of 54.7% in “unconscious and cardiac arrest” patients and a 1-year mortality of 27.7% in patients with dyspnea.26 This suggests that these two chief complaints should be considered extremely high risk, both short and long term, and there is a potential for outcome improvement in these patients.
A major strength of this study is the large study population with complete follow-up due to the Danish Civil Registration System. All adult patients visiting the ED during the inclusion period were eligible, thus minimizing selection bias. Moreover, we included patients during a whole year and thereby avoided bias from seasonal variance.
The study has some limitations. First, we excluded 7960 contacts not registered with a triage color. However, a review of the discharge diagnoses of these contacts revealed that the vast majority belonged to the minor injury group and thus correctly excluded. A minority of the contacts encompassed patients dying at the hospital (n=237), with the most frequent diagnoses being intracranial injury and cardiac arrest. These contacts represent the most acute patients attending the ED and are prehospitally reported as “major trauma,” “surgical or medical emergency” and received by coded rapid response teams and thus not triaged at arrival. The exclusion of the most acute patients causes selection bias and will most likely underestimate the mortality rates, especially in the chest pain group, the ALOC group and the focal neurological symptoms group.
Second, the classification of chief complaint might be imprecise and thereby add random error. Many patients present with several complaints9 27 and it may be difficult to determine the most appropriate chief complaint in an acute situation. Furthermore, in case of several symptoms, there are, to date, no guidelines on how to prioritize symptoms, thus placing the decision on the triaging nurse, which implies a risk to the patient of being assigned a misleading chief complaint—a potential source of misclassification. Also, chief complaint combinations/interactions may be an important factor in identifying high-risk ED patients. This is not touched on in this study due to the exclusion of patients assigned with two specific chief complaints.28 This is an area of interest in future research.
Third, we included a group with no chief complaint registered. The discharge diagnoses of this group indicated that it was a heterogenous group of medical and surgical patients and with different triage colors. The reason why these patients were not given a chief complaint is unknown. One possible explanation could be that the patients’ presenting symptoms were unspecific and none of the chief complaints predefined by DEPT fitted. However, lack of registration of chief complaint is another possible explanation and it is therefore another potential source of misclassification.
This is a single-center study and the result cannot therefore by definition be directly generalized to other EDs. However, the study population was comparable with other ED studies in terms of age, gender, admission rate and mortality,6–10 indicating that the results can be generalizable. This said, it is important to notice that the generalizability is limited due to the Danish set-up where patients suspected of cardiac arrest due to thrombosis, STEMI or stroke are not seen in the ED, but directly sent to a specialized department.
This study may be used as an impetus to more ED symptom-based research in general. As discussed, identification of risk factors among the chief complaints as well as the link between discharge diagnoses and chief complaint, and even combinations/interactions of chief complaints, is an essential area to focus future research on. This knowledge may contribute to the development or improvement of standardized ED algorithms and risk stratification tools, potentially improving patient outcomes.
