Epidemiological trends in emergency department visits by age group: a report from the National Emergency Department Information System (NEDIS) of Korea, 2020–2024

Hang A Park; Taehui Kim; Hyo Jin Kim; So-hyun Han

doi:10.15441/ceem.25.291

Clin Exp Emerg Med > Volume 12(4); 2025 > Article

Park, Kim, Kim, and Han: Epidemiological trends in emergency department visits by age group: a report from the National Emergency Department Information System (NEDIS) of Korea, 2020–2024

Commentary

Clin Exp Emerg Med 2025; 12(4): 405-413.

Published online: December 17, 2025

DOI: https://doi.org/10.15441/ceem.25.291

Epidemiological trends in emergency department visits by age group: a report from the National Emergency Department Information System (NEDIS) of Korea, 2020–2024

Hang A Park^1,^*

, Taehui Kim^2,^*

, Hyo Jin Kim²

, So-hyun Han²

¹Department of Emergency Medicine, Hallym University Dongtan Sacred Heart Hospital, Hallym University College of Medicine, Hwaseong, Korea

²National Emergency Medical Center, National Medical Center, Seoul, Korea

Correspondenc to: So-hyun Han National Emergency Medical Center, National Medical Center, 245 Eulji-ro, Jung-gu, Seoul 04564, Korea Email: peacehoi@nmc.or.kr

^*Hang A Park and Taehui Kim contributed equally to this study as co-first authors.

Received: November 29, 2025 Accepted: December 3, 2025

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/).

INTRODUCTION

Emergency departments (EDs) provide essential acute and non-routine care and serve as a safety net for populations with diverse medical needs. Monitoring trends in ED visits and outcomes is important for evidence-based emergency care policy development and for understanding how health systems respond to demographic, epidemiologic, and policy changes [1–3].

Over the past decade, many countries have experienced increased ED volumes, greater clinical complexity, and evolving admission practices [3]. These shifts were further intensified during the COVID-19 pandemic, which challenged healthcare system capacity, resource allocation, and the timeliness of emergency care [4].

Trends in post-ED outcomes, such as hospitalizations, transfers, and mortality, offer important insights into emergency care system performance [5]. Understanding these longitudinal patterns helps identify shifts in patient demand and supports data-driven policy decisions. Therefore, by extending prior National Emergency Department Information System (NEDIS) analyses to include the later phase of the COVID-19 pandemic and the 2024 medical crisis in Korea, this report provides updated national data on ED utilization and outcomes across adults, children, and older adults, including those with severe illness diagnosis codes (SIDC).

METHODS

Ethics statement

This study was approved by the Institutional Review Board of the National Medical Center (No. NMC-2023-08-094). The requirement for informed consent was waived due to the retrospective, observational, and anonymous nature of the study. All methods were performed in accordance with the relevant ethical guidelines and regulations.

Data sources and study population

The study was conducted using data from the NEDIS, a mandatory nationwide database that collects standardized administrative and clinical information from all designated emergency medical institutions in Korea [6]. Data are automatically transferred to a central server and monitored by coordinators at the National Emergency Medical Center (NEMC) [7]. Participating EDs are classified into level I (regional emergency medical and trauma centers), level II (local emergency medical centers), and level III (local emergency medical agencies) [8].

All ED visits recorded in NEDIS from January 1, 2020, to December 31, 2024, were analyzed using methods consistent with a previous study (2018–2022) [5]. Variables included demographics and prehospital and hospital information, such as age, sex, insurance type, visit characteristics, Korean Triage and Acuity Scale (KTAS) score, chief complaint, and primary and discharge diagnoses (Korean Standard Classification of Diseases [KCD], 8th Revision), as well as ED and hospital outcomes.

Statistical analysis

Descriptive analyses summarized annual ED visit counts, patient demographics, clinical characteristics, and outcomes. Age- and sex-standardized ED visit rates per 100,000 population were calculated using direct standardization with the 2020 Korean mid-year census. Standardized mortality, admission, and transfer rates were computed as weighted averages of age- and sex-specific rates within the ED population. Five-year trends were evaluated using linear regression analysis, and comparisons between 2023 and 2024 were performed using the Z-test.

Critical illness outcomes were examined using the 28 predefined SIDC categories established by the Korean Ministry of Health and Welfare [5]. Additional high-risk conditions were defined using expanded criteria: sepsis included standard sepsis codes or infection-related diagnoses accompanied by intensive care unit (ICU) admission or ED death, and cardiac arrest included either a cardiac arrest diagnosis code or documented cardiopulmonary resuscitation in the ED. Operational definitions for all categories are detailed in Supplementary Table 1.

RESULTS

Patient demographics, visit characteristics, and outcomes

A total of 37,098,865 ED visits were recorded during the study period (Table 1). Of these, 21.3 million (57.4%) were adults aged 18–64 years, 5.5 million (14.8%) were pediatric patients aged <18 years, and 10.3 million (27.7%) were older adults aged ≥65 years. The mean patient age was 46.9±24.8 years, and the median time from symptom onset to ED arrival was 290 minutes (interquartile range [IQR], 62–1,440 minutes), with the longest delays observed in older adults (median, 430 minutes; IQR, 92–2,782 minutes). Overall, 20.7% of ED visits occurred at level I centers. Disease-related presentations accounted for 72.3% of ED visits, whereas injuries accounted for 26.5%. Unintentional injuries comprised 58.1% of all injuries and were most frequent among pediatric patients (70.8%). Most patients arrived directly (90.9%), and 20.3% used the 119 ambulance service, with higher use among older adults (33.2%) compared with pediatric patients (8.5%). At initial triage, 53.4% were classified as KTAS 4–5, whereas only 5.9% were KTAS 1–2. SIDC cases accounted for 11.4% of all visits, occurring predominantly in older adults (22.0%) and least often in pediatric patients (3.3%). The mean ED length of stay was 2.8±9.8 hours, and 0.9% of patients remained in the ED for ≥24 hours. Older adults tended to stay longer (4.3±11.3 hours; ≥24 hours, 1.9%) than adults and pediatric patients. Regarding ED disposition, 77.3% of patients were discharged, 20.0% were admitted (16.9% to general wards and 3.1% to ICUs), and 0.7% died in the ED. Admission rates were highest among older adults (36.8%), whereas pediatric patients were more often discharged (90.2%). Overall in-hospital mortality was 1.7% (adults, 0.8%; pediatric patients, 0.1%; older adults, 4.7%).

Common chief complaints and diagnoses

Table 2 presents the 15 most common chief complaints and primary diagnoses overall and by age group. Abdominal pain was the most frequent chief complaint (8.8%), followed by fever (7.9%), dizziness (4.1%), and headache (4.0%). The most frequent diagnosis was acute gastroenteritis (A099), accounting for 4.8% of all ED diagnoses. U071 coronavirus disease (COVID-19, virus identified) emerged among the top 15 diagnoses during the study period.

In pediatric patients, fever (23.9%) was the most common chief complaint, followed by abdominal pain (9.7%) and vomiting (4.2%). In older adults, abdominal pain (7.8%), dyspnea (7.3%), and dizziness (6.6%) were common, and lightheadedness (R42, 4.3%) and pneumonia (J189, 2.8%) appeared among the most frequent diagnoses.

Annual changes in ED visits and ED outcomes

Standardized ED visits per 100,000 population increased from 15,562 in 2020 to 20,322 in 2023; however, they declined by 18.6% in 2024 compared with 2023 (P<0.001) (Table 3). By age group, standardized ED visits per 100,000 population decreased in 2024 compared with 2023 by 20.8% in adults, 11.0% in older adults, and 32.7% in pediatric patients (P<0.001). The 5-year linear trend was not statistically significant for the total population, any age group, or either sex.

Age- and sex-standardized hospital admission rates showed no significant linear trends; however, admission rates increased significantly across all age groups in 2024 compared with 2023 (Fig. 1). Age- and sex-standardized transfer rates declined consistently across adults, older adults, and pediatric patients, with statistically significant trends (P<0.05 in all age groups). Age- and sex-standardized in-hospital mortality rates showed no significant linear trend over the 5-year period. Rates were lowest in 2023, when the impact of the COVID-19 pandemic had largely waned, but increased significantly in 2024 compared with 2023 despite the decline in ED visits (P<0.001).

Burden and outcomes of SIDC

Table 4 summarizes ED visit volumes and outcomes for the 28 SIDC conditions, as well as traumatic brain injury, suicide attempt or self-harm, and COVID-19. COVID-19 was the most common category (24.5 visits per 1,000 ED visits), followed by sepsis using the expanded definition (18.9 per 1,000 ED visits), severe trauma (15.1 per 1,000 ED visits), ischemic stroke (14.7 per 1,000 ED visits), gastrointestinal bleeding or foreign body (11.5 per 1,000 ED visits), arrhythmia (10.9 per 1,000 ED visits), and acute kidney injury (10.9 per 1,000 ED visits). Among these high-volume categories, sepsis (expanded definition) and acute kidney injury had in-hospital mortality rates exceeding 10% (22.2% and 17.2%, respectively). Other disease groups with in-hospital mortality >10% included intracranial hemorrhage (14.5%), subdural hemorrhage (16.7%), aortic dissection (14.4%), severe burn (11.0%), acute respiratory distress syndrome/pulmonary edema (20.9%), disseminated intravascular coagulation (46.7%), and cardiac arrest (77.6%). Among time-dependent illnesses, myocardial infarction had an in-hospital mortality rate of 9.4%, and ischemic stroke had a mortality rate of 5.0%.

DISCUSSION

This analysis presents 5-year nationwide data on ED utilization and outcomes across pediatric, adult, and older adult populations in Korea using the NEDIS database. Previous reports showed a decline in ED visits early in the COVID-19 pandemic, whereas admission, transfer, and mortality rates remained relatively stable [5]. In contrast, the present analysis demonstrates a gradual recovery in ED visit rates throughout the pandemic period, consistent with findings from other studies [4]. However, the decline in ED visits observed in 2024 appears to reflect changes in healthcare-seeking behavior or ED access restrictions during the 2024–2025 medical crisis in Korea [9,10]. The prolonged disruption of health services may have limited timely access to emergency care, leading some patients to delay care or shift toward primary care settings [10,11]. Despite the reduction in ED volume, in-hospital mortality increased in 2024, suggesting that a larger proportion of patients presenting to the ED during this period were severely ill, as reported in a previous study [11]. However, given that earlier studies have found minimal effects of strike actions on in-hospital mortality, and considering the large sample size and the absence of detailed adjustments in this analysis, the observed increase in 2024 should be interpreted cautiously [12,13]. This rise may partly reflect the substantial reduction in ED visits, particularly among less severe patients during that period, although the underlying reasons for the increased mortality require further investigation. In addition, this analysis showed a decline in transfer rates over the study period; however, the reasons for this pattern are unclear and may involve multiple contributing factors. Further investigation is needed to clarify the underlying causes. Continued monitoring of national ED trends is essential for ensuring timely and effective emergency care, not only during future public health emergencies such as infectious disease outbreaks, but also in responding to ongoing changes in population demographics, disease burden, and healthcare system dynamics.

NOTES

Author contributions

Conceptualization: all authors; Data curation: TK, HJK; Methodology: all authors; Project administration: SH; Visualization: HAP, TK; Writing–original draft: HAP, TK; Writing–review & editing: all authors. All authors read and approved the final manuscript.

Conflicts of interest

The authors have no conflicts of interest to declare.

Funding

The authors received no financial support for this study.

Data availability

Data from this study were obtained from the National Emergency Medical Center (NEMC) under the Korean Ministry of Health and Welfare, and were used under license for the current study. Although the data are not publicly accessible, they are available from the corresponding author upon reasonable request with permission from the NEMC.

Supplementary materials

Supplementary Table 1.

Diagnosis codes and definitions for data extraction including 28 severe illness

ceem-25-291-Supplementary-Table-1.pdf

Supplementary materials are available from https://doi.org/10.15441/ceem.25.291.

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Fig. 1.

Age- and sex-standardized data by year. (A) Hospital admissions. (B) Transfer rates. (C) In-hospital mortality rates. ^*P<0.05 (statistically significant differences between 2023 and 2024).

Table 1.

Patient demographics, ED visit characteristics, and outcome by age group

Variable	Total (n=37,098,865)	Age group^a)
Variable	Total (n=37,098,865)	Adults (18–64 yr) (n=21,305,650)	Pediatric patients (<18 yr) (n=5,501,234)	Older adults (≥65 yr) (n=10,291,711)
Age (yr)	46.9±24.8	42.8±13.7	7.2±5.4	76.6±7.8
0–1	405,175 (1.1)		405,175 (7.4)
1–6	2,456,213 (6.6)		2,456,213 (44.6)
7–12	1,419,031 (3.8)		1,419,031 (25.8)
13–17	1,220,815 (3.3)		1,220,815 (22.2)
18–40	9,268,739 (25.0)	9,268,739 (43.5)
41–64	12,036,911 (32.4)	12,036,911 (56.5)
65–74	4,509,591 (12.2)			4,509,591 (43.8)
75–84	3,954,033 (10.7)			3,954,033 (38.4)
85–130	1,828,087 (4.9)			1,828,087 (17.8)
Unknown	270 (0.0)
Sex
Male	18,653,101 (50.3)	10,626,641 (49.9)	3,127,825 (56.9)	4,898,480 (47.6)
Female	18,445,764 (49.7)	10,679,009 (50.1)	2,373,409 (43.1)	5,393,231 (52.4)
Time from the symptom onset to ED arrival^b)
No. of patients	24,301,333	13,298,057	4,001,763	7,001,485
Median (IQR) (min)	290 (62–1,440)	246 (60–1,341)	240 (60–1,224)	430 (92–2,782)
Visit day
Weekday	21,699,904 (58.5)	12,125,872 (56.9)	3,028,348 (55.0)	6,545,534 (63.6)
Weekend or holiday	15,398,961 (41.5)	9,179,778 (43.1)	2,472,886 (45.0)	3,746,177 (36.4)
Visit time
08:00–16:00	13,840,820 (37.3)	7,173,397 (33.7)	1,499,496 (27.3)	5,167,806 (50.2)
16:00–24:00	16,258,209 (43.8)	9,536,775 (44.8)	3,055,231 (55.5)	3,666,088 (35.6)
24:00–08:00	6,999,836 (18.9)	4,595,478 (21.6)	946,507 (17.2)	1,457,817 (14.2)
Type of ED
Level I	7,679,592 (20.7)	3,862,042 (18.1)	1,436,792 (26.1)	2,380,745 (23.1)
Level II	16,931,322 (45.6)	9,643,124 (45.3)	2,590,383 (47.1)	4,697,782 (45.6)
Level III	12,487,951 (33.7)	7,800,484 (36.6)	1,474,059 (26.8)	3,213,184 (31.2)
Disease category^b)
Disease	26,821,758 (72.3)	15,053,977 (70.7)	3,643,168 (66.2)	8,124,482 (78.9)
Injury	9,834,738 (26.5)	6,006,541 (28.2)	1,818,233 (33.1)	2,009,878 (19.5)
Dead on arrival	77,004 (0.2)	21,461 (0.1)	479 (0.0)	55,059 (0.5)
Other or unknown	365,365 (1.0)	223,671 (1.0)	39,354 (0.7)	102,292 (1.0)
Intentionality^b)	9,834,738 (100)	6,006,541 (100)	1,818,233 (100)	2,009,878 (100)
Accident	5,713,123 (58.1)	3,266,460 (54.4)	1,286,562 (70.8)	1,160,094 (57.7)
Suicidal	176,345 (1.8)	138,006 (2.3)	17,376 (1.0)	20,962 (1.0)
Violence	168,204 (1.7)	137,662 (2.3)	16,354 (0.9)	14,187 (0.7)
Other	154,695 (1.6)	121,129 (2.0)	13,613 (0.7)	19,953 (1.0)
Unknown	3,622,371 (36.8)	2,343,284 (39.0)	484,328 (26.6)	794,682 (39.5)
Insurance type
National health insurance	32,686,548 (88.1)	18,600,780 (87.3)	5,231,604 (95.1)	8,854,094 (86.0)
Automobile insurance	1,096,922 (3.0)	814,934 (3.8)	80,074 (1.5)	201,911 (2.0)
Occupational health and safety insurance	108,774 (0.3)	94,770 (0.4)	124 (0.0)	13,868 (0.1)
Private insurance	2,774 (0.0)	2,133 (0.0)	142 (0.0)	499 (0.0)
Medical aid type 1	1,987,662 (5.4)	888,746 (4.2)	73,877 (1.3)	1,025,021 (10.0)
Medical aid type 2	337,566 (0.9)	259,560 (1.2)	57,906 (1.1)	20,100 (0.2)
General insurance	596,661 (1.6)	456,905 (2.1)	36,965 (0.7)	102,658 (1.0)
Other	185,924 (0.5)	133,198 (0.6)	10,508 (0.2)	42,200 (0.4)
Unknown	96,034 (0.3)	54,624 (0.3)	10,034 (0.2)	31,360 (0.3)
Route of arrival
Direct visit	33,704,570 (90.9)	19,834,372 (93.1)	5,126,142 (93.2)	8,743,841 (85.0)
Transfer from other hospital	2,786,344 (7.5)	1,197,493 (5.6)	325,863 (5.9)	1,262,981 (12.3)
Referred from outpatient clinics	561,269 (1.5)	246,002 (1.2)	43,356 (0.8)	271,909 (2.6)
Other	13,642 (0.0)	7,240 (0.0)	1,840 (0.0)	4,561 (0.0)
Unknown	33,040 (0.1)	20,543 (0.1)	4,033 (0.1)	8,419 (0.1)
Transport
119 Ambulance	7,540,276 (20.3)	3,653,827 (17.1)	468,942 (8.5)	3,417,462 (33.2)
Other medical institution ambulance	234,759 (0.6)	83,574 (0.4)	6,638 (0.1)	144,542 (1.4)
Other ambulance	962,218 (2.6)	318,770 (1.5)	24,056 (0.4)	619,384 (6.0)
Police or official transport	40,390 (0.1)	35,135 (0.2)	1,361 (0.0)	3,892 (0.0)
Air transport	22,516 (0.1)	13,856 (0.1)	2,063 (0.0)	6,597 (0.1)
Other transport	27,570,000 (74.3)	16,740,000 (78.6)	4,895,705 (89.0)	5,936,108 (57.7)
Walk-in	632,413 (1.7)	413,509 (1.9)	93,463 (1.7)	125,432 (1.2)
Other	58,881 (0.2)	24,398 (0.1)	4,810 (0.1)	29,673 (0.3)
Unknown	33,974 (0.1)	21,111 (0.1)	4,196 (0.1)	8,621 (0.1)
Initial triage (KTAS score)^b)
1	433,313 (1.2)	142,187 (0.7)	13,775 (0.3)	277,324 (2.7)
2	1,768,107 (4.8)	750,860 (3.5)	148,111 (2.7)	869,113 (8.4)
3	13,891,416 (37.4)	7,224,035 (33.9)	1,935,311 (35.2)	4,732,014 (46.0)
4–5	19,827,228 (53.4)	12,465,924 (58.5)	3,265,397 (59.4)	4,095,783 (39.8)
Other/unknown	1,178,801 (3.2)	722,644 (3.4)	138,640 (2.5)	317,477 (3.1)
Severe illness diagnosis^c)	4,212,883 (11.4)	1,765,999 (8.3)	182,292 (3.3)	2,264,557 (22.0)
Length of stay^d)
Mean±SD (hr)	2.8 ± 9.8	2.4 ± 8.9	1.9 ± 9.9	4.3 ± 11.3
Median (IQR) (hr)	1.7 (0.7–3.1)	1.5 (0.6–2.7)	1.1 (0.4–2.4)	2.5 (1.3–4.6)
0–6 hr	33,529,765 (90.4)	19,799,501 (92.9)	5,247,371 (95.4)	8,482,680 (82.4)
6–12 hr	2,302,211 (6.2)	981,546 (4.6)	191,904 (3.5)	1,128,754 (11.0)
12–24 hr	883,020 (2.4)	365,174 (1.7)	47,259 (0.9)	470,585 (4.6)
≥24 hr	322,786 (0.9)	121,986 (0.6)	6,902 (0.1)	193,898 (1.9)
Unknown	61,083 (0.2)	37,443 (0.2)	7,798 (0.1)	15,794 (0.2)
ED disposition
Discharge	28,664,776 (77.3)	17,735,758 (83.2)	4,961,195 (90.2)	5,967,668 (58.0)
Admission^e)	7,428,617 (20.0)	3,148,829 (14.8)	496,811 (9.0)	3,782,930 (36.8)
General ward	6,255,742 (16.9)	2,717,747 (12.8)	468,081 (8.5)	3,069,880 (29.8)
Intensive care unit	1,139,056 (3.1)	411,771 (1.9)	27,642 (0.5)	699,630 (6.8)
Transfer	613,224 (1.7)	253,858 (1.2)	24,618 (0.5)	334,737 (3.3)
Hopeless discharge	2,523 (0.0)	570 (0.0)	48 (0.0)	1,905 (0.0)
Death	247,944 (0.7)	71,147 (0.3)	2,667 (0.1)	174,120 (1.7)
Other	90,239 (0.2)	63,810 (0.3)	9,490 (0.2)	16,939 (0.2)
Unknown	51,542 (0.1)	31,678 (0.2)	6,405 (0.1)	13,412 (0.1)
Hospital disposition
Discharge	34,875,444 (94.0)	20,536,840 (96.4)	5,441,353 (98.9)	8,897,076 (86.5)
Transfer	1,272,225 (3.4)	444,129 (2.1)	32,193 (0.6)	795,888 (7.7)
Hopeless discharge	6,466 (0.0)	1,826 (0.0)	71 (0.0)	4,569 (0.0)
Death	643,034 (1.7)	159,152 (0.8)	4,109 (0.1)	479,762 (4.7)
Other	111,287 (0.3)	72,422 (0.3)	10,186 (0.2)	28,679 (0.3)
Unknown	190,409 (0.5)	91,281 (0.4)	13,322 (0.2)	85,737 (0.8)

Values are presented as number (%), unless otherwise indicated. Percentages may not total 100 due to rounding.

ED, emergency department; KTAS, Korean Triage Acuity Scale; IQR, interquartile range; SD, standard deviation.

^a)Patients with missing age information were excluded from the analysis (n=270).

^b)Reporting not obligatory for level III EDs (recording KTAS scores became mandatory starting from 2021); hence, there is a higher likelihood of missing data for level III EDs.

^c)28 Severe illness diagnosis codes are listed in Supplementary Table 1.

^d)Any ED length of stay over 5 days was treated as 5 days.

^e)Admission locations include areas other than general wards or intensive care units, including unspecified locations.

Table 2.

Top 15 chief complaints by UMLS code and main diagnosis by KCD code

Rank	UMLS code	No. of patients (%)	KCD code	No. of patients (%)
Total (n=37,098,865)
1	Abdominal pain	3,946,827 (8.8)	A099 (gastroenteritis and colitis of unspecified origin)	1,776,048 (4.8)
2	Fever	3,530,106 (7.9)	R1049 (unspecified abdominal pain)	1,054,325 (2.9)
3	Dizziness	1,853,536 (4.1)	R42 (lightheadedness)	1,024,586 (2.8)
4	Headache	1,795,042 (4.0)	R5099 (hyperpyrexia NOS)	927,726 (2.5)
5	Dyspnea	1,416,604 (3.2)	Z115 (special screening examination for other viral disease)	703,181 (1.9)
6	Vomiting	1,088,639 (2.4)	R51 (headache)	617,324 (1.7)
7	Diarrhea	907,524 (2.0)	S610 (open wound of finger(s) without damage to nail)	609,640 (1.7)
8	Nausea	869,155 (1.9)	U071 (coronavirus disease, virus identified [COVID-19, virus identified])	607,018 (1.6)
9	Generalized weakness	819,326 (1.8)	S0600 (concussion, without open intracranial wound)	574,796 (1.6)
10	Epigastric pain	805,449 (1.8)	L509 (urticaria, unspecified)	457,785 (1.2)
11	Chest pain	786,829 (1.8)	R074 (chest pain, unspecified)	456,768 (1.2)
12	Cough	766,726 (1.7)	N201 (calculus of ureter)	447,421 (1.2)
13	Sore throat	739,620 (1.7)	J189 (pneumonia, unspecified)	425,612 (1.2)
14	Back pain	704,491 (1.6)	J069 (upper respiratory disease, acute)	390,925 (1.1)
15	Myalgia	638,766 (1.4)	T140 (superficial injury of unspecified body region)	338,815 (0.9)
Pediatric patients (<18 yr) (n=5,501,234)
1	Fever	1,287,825 (23.9)	R5099 (hyperpyrexia NOS)	405,286 (7.4)
2	Abdominal pain	522,431 (9.7)	A099 (gastroenteritis and colitis of unspecified origin)	367,155 (6.7)
3	Vomiting	226,766 (4.2)	R1049 (unspecified abdominal pain)	178,629 (3.3)
4	Headache	137,165 (2.6)	S0600 (concussion, without open intracranial wound)	138,802 (2.5)
5	Cough	125,886 (2.3)	B349 (viraemia NOS)	123,296 (2.3)
6	Skin rash	115,726 (2.2)	L509 (urticaria, unspecified)	115,099 (2.1)
7	Urticaria	100,383 (1.9)	J069 (upper respiratory disease, acute)	105,648 (1.9)
8	Head trauma	82,159 (1.5)	S018 (open wound of other parts of head)	104,287 (1.9)
9	Pain in finger	78,938 (1.5)	U071 (coronavirus disease, virus identified [COVID-19, virus identified])	97,579 (1.8)
10	Ankle pain	70,816 (1.3)	J00 (acute rhinitis)	94,703 (1.7)
11	Sore throat	66,482 (1.2)	J029 (acute bronchitis, unspecified)	81,158 (1.5)
12	Seizures	61,706 (1.1)	J101 (seasonal influenza virus identified influenza with other respiratory manifestations)	76,562 (1.4)
13	Dyspnea	61,571 (1.1)	J111 (influenza with other respiratory manifestations, virus not identified)	71,384 (1.3)
14	Pain in elbow	60,525 (1.1)	T140 (superficial injury of unspecified body region)	64,390 (1.2)
15	Diarrhea	45,409 (0.8)	S010 (open wound of scalp)	63,683 (1.2)
Older adults (≥65 yr) (n=10,291,711)
1	Abdominal pain	786,086 (7.8)	R42 (lightheadedness)	443,418 (4.3)
2	Dyspnea	735,053 (7.3)	J189 (pneumonia, unspecified)	284,860 (2.8)
3	Dizziness	659,342 (6.6)	A099 (gastroenteritis and colitis of unspecified origin)	262,824 (2.6)
4	Fever	586,141 (5.8)	R1049 (unspecified abdominal pain)	216,558 (2.1)
5	Generalized weakness	442,056 (4.4)	U071 (coronavirus disease, virus identified [COVID-19, virus identified])	202,537 (2.0)
6	Headache	287,664 (2.9)	R5099 (hyperpyrexia NOS)	159,802 (1.6)
7	Chest pain	250,831 (2.5)	I639 (cerebral infarction, unspecified)	152,858 (1.5)
8	Back pain	198,484 (2.0)	R060 (shortness of breath)	146,773 (1.4)
9	Coxalgia	169,863 (1.7)	R074 (chest pain, unspecified)	136,173 (1.3)
10	Epigastric pain	142,541 (1.4)	N390 (urinary tract infection, site not specified)	128,721 (1.3)
11	Syncope	107,119 (1.1)	S0600 (concussion, without open intracranial wound)	125,233 (1.2)
12	Chest discomfort	101,352 (1.0)	R51 (headache)	118,924 (1.2)
13	Vomiting	97,364 (1.0)	R53 (chronic debility)	117,842 (1.2)
14	Low back pain	96,639 (1.0)	Z115 (special screening examination for other viral diseases)	107,380 (1.1)
15	Diarrhea	96,029 (1.0)	K5909 (other and unspecified constipation)	106,371 (1.0)

UMLS, Unified Medical Language System; KCD, Korean Standard Classification of Diseases.

Table 3.

Age- and sex-standardized emergency department visits per 100,000 population (2020–2024)

Sex	Year					P for trend
Sex	2020	2021	2022	2023	2024^a)	P for trend
Total	15,562	16,093	17,973	20,322	16,543	0.378
Male	16,873	17,102	19,150	21,650	17,860	0.362
Female	14,250	15,084	16,797	18,995	15,226	0.398
Adults (18–64 yr)	11,913	12,147	12,336	13,051	10,341	0.558
Male	12,071	11,871	11,899	12,450	10,016	0.297
Female	11,755	12,424	12,772	13,651	10,667	0.830
Pediatric patients (<18 yr)	11,702	11,596	15,144	19,024	12,796	0.406
Male	12,984	12,845	16,874	21,008	14,215	0.403
Female	10,419	10,347	13,414	17,040	11,378	0.409
Older adults (≥65 yr)	23,380	25,048	28,684	32,736	29,140	0.085
Male	26,682	28,096	32,279	36,917	33,231	0.073
Female	20,078	21,999	25,090	28,554	25,050	0.102

^a)All comparisons between 2023 and 2024 showed statistically significant differences.

Table 4.

Summary of ED outcomes for 28 severe illness codes and selected diagnostic categories (including traumatic brain injury, suicide attempt/self-harm, and COVID-19)

Disease category	No. of patients	No. of patients per 1,000 ED visits	ED discharge rate (%)	Transfer rate (%)	Admission rate (%)	ICU admission rate (%)	No. of hospital deaths	In-hospital mortality (%)
Myocardial infarction	213,538	5.8	4.7	9.2	84.3	55.7	20,012	9.4
Ischemic stroke	546,175	14.7	15.0	4.3	80.4	23.2	27,359	5.0
Intracranial hemorrhage	142,413	3.8	6.3	10.9	81.5	57.4	20,613	14.5
Cardiac arrest (diagnosis code)	165,481	4.5	0.7	5.4	33.3	27.9	130,353	78.8
Cardiac arrest (diagnosis code or cardiopulmonary resuscitation in ED)^a)	205,617	5.5	2.9	5.6	26.6	24.1	159,527	77.6
Subdural hemorrhage	53,370	1.4	4.0	16.5	77.4	65.8	8,894	16.7
Severe trauma	559,392	15.1	21.0	7.7	69.6	25.1	29,494	5.3
Sepsis (diagnosis code)	229,397	6.2	5.3	3.3	90.1	37.3	54,413	23.7
Sepsis (extended definition)^a),b)	701,157	18.9	1.9	1.6	93.4	72.5	155,928	22.2
Aortic dissection	24,069	0.6	9.0	21.3	64.3	44.8	3,467	14.4
Biliary disease	358,891	9.7	11.7	6.0	82.1	6.5	10,224	2.8
Surgical diagnosis	261,395	7.0	5.8	5.5	88.2	12.3	12,608	4.8
GI bleeding/FB	428,153	11.5	22.4	3.8	72.9	18.5	25,468	5.9
Tracheal bleeding/FB	65,731	1.8	36.0	3.2	59.8	10.5	4,131	6.3
Intoxication	302,148	8.1	71.2	2.4	25.5	12.9	3,652	1.2
Perinatal disease	70,139	1.9	8.7	1.2	90.0	3.2	67	0.1
Premature (low birth weight)	17,465	0.5	15.8	1.4	82.7	61.0	109	0.6
Severe burn	1,312	0.0	17.9	18.5	61.7	33.3	144	11.0
Status epilepticus	24,218	0.7	9.9	4.9	84.9	44.5	1,746	7.2
Meningitis	54,079	1.5	28.9	2.0	68.9	13.5	1,893	3.5
Diabetic encephalopathy	47,813	1.3	9.0	5.9	83.8	45.1	3,977	8.3
Pulmonary embolism/DVT	106,614	2.9	17.2	2.8	79.2	22.2	10,313	9.7
Arrhythmia	403,265	10.9	22.3	2.0	75.2	26.4	31,470	7.8
ARDS/pulmonary edema	207,161	5.6	5.6	3.2	89.8	36.2	43,339	20.9
DIC	14,370	0.4	3.2	0.7	94.2	53.4	6,713	46.7
Intussusception/ileus	95,320	2.6	13.7	4.5	81.5	6.6	3,308	3.5
Amputation	36,441	1.0	23.9	5.2	69.3	30.2	1,241	3.4
Acute kidney injury	404,505	10.9	8.6	3.8	86.7	30.8	69,408	17.2
Ophthalmic emergency	40,811	1.1	55.8	0.4	43.6	3.1	209	0.5
Urologic emergency	19,529	0.5	69.4	1.3	29.2	1.4	69	0.4
TBI^a),c)	246,811	6.7	19.5	8.7	70.7	38.8	18,118	7.3
Suicide attempt and self-harm^a),d)	209,746	5.7	63.4	3.9	29.1	15.5	8,129	3.9
COVID-19^a)	907,336	24.5	63.7	2.2	32.8	4.7	28,482	3.1

ED, emergency department; ICU, intensive care unit; GI, gastrointestinal; FB, foreign body; DVT, deep vein thrombosis; ARDS, acute respiratory distress syndrome; DIC, disseminated intravascular coagulation; TBI, traumatic brain injury.

^a)In addition to the 28 predefined severe illness codes, several diagnostic codes were additionally selected and included in this table.

^b)(Infection diagnosis code AND ICU admission/ED death) OR sepsis/septic shock diagnosis code.

^c)Identified based on International Classification of Diseases, 10th Revision (ICD-10) diagnostic codes (S06.1–S06.9) that correspond to the TBI definition established by the Korea Disease Control and Prevention Agency.

^d)Any of the following three conditions: (1) the intention of self-harm or suicide; (2) initial severity classification falls into the suicide attempt, suicidal intent, or suicidal ideation categories under the Korean Triage and Acuity Scale (KTAS); or (3) discharge diagnosis codes based on the Korean Standard Classification of Disease (KCD), X60–X84 (excluding X65).