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Emergency department utilization in elderly patients: a report from the National Emergency Department Information System (NEDIS) of Korea, 2018-2022

Clinical and Experimental Emergency Medicine 2023;10(S):S26-S35.
Published online: November 8, 2023

1Department of Emergency Medicine, Seoul National University Bundang Hospital, Seongnam, Korea

2Department of Emergency Medicine, Seoul National University College of Medicine, Seoul, Korea

3Disaster Medicine Research Center, Seoul National University Medical Research Center, Seoul, Korea

4National Emergency Medical Center, National Medical Center, Seoul, Korea

5Department of Emergency Medicine, Chosun University Hospital, Gwangju, Korea

6Department of Emergency Medicine, Seoul National University Hospital, Seoul, Korea

Correspondence to: Sumin Baek Department of Emergency Medicine, Seoul National University Bundang Hospital, 82 Gumi-ro 173beon-gil, Bundang-gu, Seongnam 13620, Korea Email: pueril0408@gmail.com
Co-correspondence to: Young Sun Ro Department of Emergency Medicine, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 03080, Korea Email: Ro.youngsun@gmail.com
• Received: October 4, 2023   • Accepted: October 11, 2023

Copyright © 2023 The Korean Society of Emergency Medicine

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/).

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Emergency department utilization in elderly patients: a report from the National Emergency Department Information System (NEDIS) of Korea, 2018-2022
Clin Exp Emerg Med. 2023;10(S):S26-S35.   Published online November 8, 2023
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Emergency department utilization in elderly patients: a report from the National Emergency Department Information System (NEDIS) of Korea, 2018-2022
Clin Exp Emerg Med. 2023;10(S):S26-S35.   Published online November 8, 2023
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Emergency department utilization in elderly patients: a report from the National Emergency Department Information System (NEDIS) of Korea, 2018-2022
Image
Fig. 1. Trends associated with emergency department (ED) visits by year, 2018–2022. (A) Age- and sex-standardized ED visits per 100,000 population. (B) Age- and sex-standardized mortality rates. (C) Hospital admission rates. (D) Transfer rates.
Emergency department utilization in elderly patients: a report from the National Emergency Department Information System (NEDIS) of Korea, 2018-2022
Variable Total KTAS score
1–2 3 4–5 Unknowna)
No. of patients 9,803,065 (100) 1,077,723 (11.0) 4,161,632 (42.5) 3,643,078 (37.2) 920,632 (9.4)
Age (yr)
 Mean±SD 76.4±7.6 78.0±7.9 76.7±7.5 75.5±7.5 76.1±7.7
 65–74 4,332,884 (44.2) 385,687 (35.8) 1,733,096 (41.6) 1,796,568 (49.3) 417,533 (45.4)
 75–84 3,892,814 (39.7) 459,133 (42.6) 1,727,778 (41.5) 1,343,903 (36.9) 362,000 (39.3)
 85–130 1,577,367 (16.1) 232,903 (21.6) 700,758 (16.8) 502,607 (13.8) 141,099 (15.3)
Sex
 Male 4,665,941(47.6) 567,631 (52.7) 1,931,558 (46.4) 1,742,034 (47.8) 424,718 (46.1)
 Female 5,137,124 (52.4) 510,092 (47.3) 2,230,074 (53.6) 1,901,044 (52.2) 495,914 (53.9)
Time from symptom onset to visita)
 No. of extractable patients 6,626,069 930,768 3,495,427 2,199,449 425
 Median (IQR) (min) 439 (91–2,856) 158 (60–904) 605 (126–2,889) 421 (72–2,811) 202 (46–1,010)
Visit day
 Weekday 6,202,515 (63.3) 754,015 (70.0) 2,857,999 (68.7) 2,117,222 (58.1) 473,279 (51.4)
 Weekend or holiday 3,600,550 (36.7) 323,708 (30.0) 1,303,633 (31.3) 1,525,856 (41.9) 447,353 (48.6)
Visit time of day
 08:00–16:00 4,882,786 (49.8) 532,964 (49.5) 2,162,443 (52.0) 1,755,154 (48.2) 432,225 (46.9)
 16:00–24:00 3,536,527 (36.1) 372,469 (34.6) 1,432,477 (34.4) 1,369,567 (37.6) 362,014 (39.3)
 24:00–08:00 1,383,752 (14.1) 172,290 (16.0) 566,712 (13.6) 518,357 (14.2) 126,393 (13.7)
Type of ED
 Level I 2,305,729 (23.5) 402,150 (37.3) 1,337,868 (32.1) 565,644 (15.5) 67 (0.0)
 Level II 4,369,716 (44.6) 533,115 (49.5) 2,170,984 (52.2) 1,665,235 (45.7) 382 (0.0)
 Level III 3,127,620 (31.9) 142,458 (13.2) 652,780 (15.7) 1,412,199 (38.8) 920,183 (100)
Disease categorya)
 Disease 7,330,200 (74.8) 936,858 (86.9) 3,578,559 (86.0) 2,520,053 (69.2) 294,730 (32.0)
 Injury 1,831,490 (18.7) 84,902 (7.9) 569,792 (13.7) 1,070,444 (29.4) 106,352 (11.6)
 Dead on arrival 59,219 (0.6) 49,443 (4.6) 15 (0.0) 731 (0.0) 9,030 (1.0)
 Other or unknown 582,156 (5.9) 6,520 (0.6) 13,266 (0.3) 51,850 (1.4) 510,520 (55.5)
Intentionalitya)
 No. of extractable patients 1,831,490 84,902 569,792 1,070,444 106,352
 Accident 1,136,171 (62.0) 56,111 (66.1) 437,162 (76.7) 642,841 (60.1) 57 (0.1)
 Suicidal 20,370 (1.1) 11,500 (13.5) 7,419 (1.3) 1,448 (0.1) 3 (0.0)
 Violence 15,221 (0.8) 498 (0.6) 3,671 (0.6) 11,051 (1.0) 1 (0.0)
 Other 19,949 (1.1) 1,307 (1.5) 4,221 (0.7) 14,412 (1.3) 9 (0.0)
 Unknown 639,779 (34.9) 15,486 (18.2) 117,319 (20.6) 400,692 (37.4) 106,282 (99.9)
Insurance
 National Health Insurance 8,370,461 (85.4) 911,195 (84.5) 3,624,483 (87.1) 3,062,213 (84.1) 772,570 (83.9)
 Automobile insurance 222,176 (2.3) 14,741 (1.4) 63,815 (1.5) 118,115 (3.2) 25,505 (2.8)
 Occupational health and safety insurance 15,426 (0.2) 1,440 (0.1) 4,644 (0.1) 6,136 (0.2) 3,206 (0.3)
 Private insurance 308 (0.0) 208 (0.0) 29 (0.0) 67 (0.0) 4 (0.0)
 Medical aid type 1 987,914 (10.1) 107,886 (10.0) 418,727 (10.1) 366,252 (10.1) 95,049 (10.3)
 Medical aid type 2 19,919 (0.2) 2,141 (0.2) 8,192 (0.2) 7,831 (0.2) 1,755 (0.2)
 General insurance 109,385 (1.1) 32,518 (3.0) 17,583 (0.4) 43,451 (1.2) 15,833 (1.7)
 Other 41,338 (0.4) 4,085 (0.4) 12,175 (0.3) 18,691 (0.5) 6,387 (0.7)
 Unknown 36,138 (0.4) 3,509 (0.3) 11,984 (0.3) 20,322 (0.6) 323 (0.0)
Route of arrival
 Direct visit 8,231,692 (84.0) 815,785 (75.7) 3,225,178 (77.5) 3,312,810 (90.9) 877,919 (95.4)
 Transfer from other hospital 1,295,789 (13.2) 230,751 (21.4) 773,961 (18.6) 258,329 (7.1) 32,748 (3.6)
 Referral from outpatient clinic 262,133 (2.7) 29,518 (2.7) 159,699 (3.8) 65,986 (1.8) 6,930 (0.8)
 Other 5,184 (0.1) 744 (0.1) 1,069 (0.0) 1,722 (0.0) 1,649 (0.2)
 Unknown 8,267 (0.1) 925 (0.1) 1,725 (0.0) 4,231 (0.1) 1,386 (0.2)
Transport
 119 Ambulance 3,055,040 (31.2) 553,554 (51.4) 1,444,014 (34.7) 841,559 (23.1) 215,913 (23.5)
 Other medical institution ambulance 174,063 (1.8) 41,294 (3.8) 86,885 (2.1) 32,247 (0.9) 13,637 (1.5)
 Other ambulance 643,361 (6.6) 164,831 (15.3) 345,585 (8.3) 107,448 (2.9) 25,497 (2.8)
 Police or official transport 4,164 (0.0) 816 (0.1) 1,285 (0.0) 1,368 (0.0) 695 (0.1)
 Air transport 7,242 (0.1) 2,779 (0.3) 2,707 (0.1) 1,283 (0.0) 473 (0.1)
 Ambulatory 5,878,374 (60.0) 308,896 (28.7) 2,269,605 (54.5) 2,644,603 (72.6) 655,270 (71.2)
 Other 31,650 (0.3) 4,693 (0.4) 9,707 (0.2) 10,160 (0.3) 7,090 (0.8)
 Unknown 9,171 (0.1) 860 (0.1) 1,844 (0.0) 4,410 (0.1) 2,057 (0.2)
Initial KTAS scorea)
 1 246,822 (2.5) 245,324 (22.8) 834 (0.0) 664 (0.0) 0 (0)
 2 757,254 (7.7) 740,521 (68.7) 9,535 (0.2) 7,198 (0.2) 0 (0)
 3 3,999,201 (40.8) 66,048 (6.1) 3,874,223 (93.1) 58,930 (1.6) 0 (0)
 4–5 3,877,093 (39.5) 25,574 (2.4) 276,510 (6.6) 3,575,009 (98.1) 0 (0)
 Other or unknown 922,695 (9.4) 256 (0.0) 530 (0.0) 1,277 (0.0) 920,632 (100)
Severe illness diagnosis 2,083,652 (21.3) 559,012 (51.9) 1,151,597 (27.7) 281,731 (7.7) 91,312 (9.9)
ED length of stay
 Mean±SD (min) 269.1±425.5 419.9±608.2 360.6±478.2 162.4±263.9 100.5±216.0
 Median (IQR) (min) 148 (73–287) 229 (116–450) 215 (127–384) 98 (40–183) 65 (24–120)
 0–6 hr 7,955,429 (81.2) 729,441 (67.7) 3,019,527 (72.6) 3,313,485 (91) 892,976 (97)
 6–12 hr 1,106,944 (11.3) 187,655 (17.4) 685,263 (16.5) 219,698 (6.0) 14,328 (1.6)
 12–24 hr 487,875 (5.0) 102,364 (9.5) 309,374 (7.4) 71,316 (2.0) 4,821 (0.5)
 ≥24 hr 232,563 (2.4) 56,601 (5.3) 143,467 (3.4) 28,402 (0.8) 4,093 (0.4)
 Unknown 20,254 (0.2) 1,662 (0.2) 4,001 (0.1) 10,177 (0.3) 4,414 (0.5)
ED disposition
 Discharge 5,707,679 (58.2) 227,718 (21.1) 1,969,321 (47.3) 2,882,640 (79.1) 628,000 (68.2)
 Admissionb) 3,538,895 (36.1) 624,418 (57.9) 2,008,368 (48.3) 675,183 (18.5) 230,926 (25.1)
  General wardc) 2,882,209 (81.4) 322,587 (51.7) 1,713,736 (85.3) 638,380 (94.5) 207,506 (89.9)
  Intensive care unitc) 647,324 (18.3) 300,155 (48.1) 289,489 (14.4) 34,574 (5.1) 23,106 (10.0)
 Transfer 348,339 (3.6) 75,556 (7.0) 165,654 (4.0) 66,296 (1.8) 40,833 (4.4)
 Hopeless discharge 2,185 (0.0) 1,206 (0.1) 754 (0.0) 166 (0.0) 59 (0.0)
 Death 172,644 (1.8) 146,521 (13.6) 7,099 (0.2) 1,330 (0.0) 17,694 (1.9)
 Other 19,155 (0.2) 956 (0.1) 7,092 (0.2) 9,220 (0.3) 1,887 (0.2)
 Unknown 14,168 (0.1) 1,348 (0.1) 3,344 (0.1) 8,243 (0.2) 1,233 (0.1)
Hospital disposition
 Discharge 8,437,152 (86.1) 617,510 (57.3) 3,563,059 (85.6) 3,448,017 (94.6) 808,566 (87.8)
 Transfer 793,333 (8.1) 187,257 (17.4) 421,634 (10.1) 126,352 (3.5) 58,090 (6.3)
 Hopeless discharge 4,917 (0.1) 2,340 (0.2) 2,070 (0.0) 399 (0.0) 108 (0.0)
 Death 446,931 (4.6) 257,074 (23.9) 132,789 (3.2) 27,967 (0.8) 29,101 (3.2)
 Other 33,001 (0.3) 3,570 (0.3) 13,899 (0.3) 12,480 (0.3) 3,052 (0.3)
 Unknown 87,731 (0.9) 9,972 (0.9) 28,181 (0.7) 27,863 (0.8) 21,715 (2.4)
Variable Total Age (yr)
65–74 75–84 85–130
No. of patients 9,803,065 (100) 4,332,884 (44.2) 3,892,814 (39.7) 1,577,367 (16.1)
Age (mean±SD) (yr) 76.4±7.6 69.3±2.9 79.3±2.8 88.5±3.4
Sex
 Male 4,665,941 (47.6) 2,319,456 (53.5) 1,786,058 (45.9) 560,427 (35.5)
 Female 5,137,124 (52.4) 2,013,428 (46.5) 2,106,756 (54.1) 1,016,940 (64.5)
Time from symptom onset to visita)
 No. of extractable patients 6,626,069 2,874,742 2,684,934 1,066,393
 Median (IQR) (min) 439 (91–2,856) 383 (79–2,274) 494 (102–2,880) 467 (101–2,880)
Visit day
 Weekday 6,202,515 (63.3) 2,644,656 (61.0) 2,506,144 (64.4) 1,051,715 (66.7)
 Weekend or holiday 3,600,550 (36.7) 1,688,228 (39.0) 1,386,670 (35.6) 525,652 (33.3)
Visit time of day
 08:00–16:00 4,882,786 (49.8) 1,986,753 (45.9) 2,025,290 (52.0) 870,743 (55.2)
 16:00–24:00 3,536,527 (36.1) 1,654,155 (38.2) 1,353,711 (34.8) 528,661 (33.5)
 24:00–08:00 1,383,752 (14.1) 691,976 (16.0) 513,813 (13.2) 177,963 (11.3)
Type of ED
 Level I 2,305,729 (23.5) 994,248 (22.9) 958,097 (24.6) 353,384 (22.4)
 Level II 4,369,716 (44.6) 1,904,775 (44.0) 1,745,286 (44.8) 719,655 (45.6)
 Level III 3,127,620 (31.9) 1,433,861 (33.1) 1,189,431 (30.6) 504,328 (32.0)
Disease categorya)
 Disease 7,330,200 (74.8) 3,179,062 (73.4) 2,962,246 (76.1) 1,188,892 (75.4)
 Injury 1,831,490 (18.7) 881,211 (20.3) 675,597 (17.4) 274,682 (17.4)
 Dead on arrival 59,219 (0.6) 9,597 (0.2) 20,768 (0.5) 28,854 (1.8)
 Other or unknown 582,156 (5.9) 263,014 (6.1) 234,203 (6) 84,939 (5.4)
Intentionalitya)
 No. of extractable patients 1,831,490 881,211 675,597 274,682
 Accident 1,136,171 (62) 531,628 (60.3) 429,259 (63.5) 175,284 (63.8)
 Suicidal 20,370 (1.1) 9,091 (1.0) 8,619 (1.3) 2,660 (1.0)
 Violence 15,221 (0.8) 10,430 (1.2) 3,964 (0.6) 827 (0.3)
 Other 19,949 (1.1) 10,595 (1.2) 6,697 (1.0) 2,657 (1.0)
 Unknown 639,779 (34.9) 319,467 (36.3) 227,058 (33.6) 93,254 (33.9)
Insurance
 National Health Insurance 8,370,461 (85.4) 3,683,294 (85.0) 3,355,540 (86.2) 1,331,627 (84.4)
 Automobile insurance 222,176 (2.3) 137,299 (3.2) 72,664 (1.9) 12,213 (0.8)
 Occupational health and safety insurance 15,426 (0.2) 12,513 (0.3) 2,567 (0.1) 346 (0.0)
 Private insurance 308 (0.0) 110 (0.0) 86 (0.0) 112 (0.0)
 Medical aid type 1 987,914 (10.1) 403,169 (9.3) 391,439 (10.1) 193,306 (12.3)
 Medical aid type 2 19,919 (0.2) 10,954 (0.3) 6,644 (0.2) 2,321 (0.1)
 General insurance 109,385 (1.1) 50,878 (1.2) 35,691 (0.9) 22,816 (1.4)
 Other 41,338 (0.4) 19,247 (0.4) 13,827 (0.4) 8,264 (0.5)
 Unknown 36,138 (0.4) 15,420 (0.4) 14,356 (0.4) 6,362 (0.4)
Route of arrival
 Direct visit 8,231,692 (84.0) 3,746,793 (86.5) 3,198,308 (82.2) 1,286,591 (81.6)
 Transfer from other hospital 1,295,789 (13.2) 463,812 (10.7) 578,442 (14.9) 253,535 (16.1)
 Referral from outpatient clinic 262,133 (2.7) 116,664 (2.7) 110,907 (2.8) 34,562 (2.2)
 Other 5,184 (0.1) 2,025 (0.0) 1,913 (0.0) 1,246 (0.1)
 Unknown 8,267 (0.1) 3,590 (0.1) 3,244 (0.1) 1,433 (0.1)
Transport
 119 Ambulance 3,055,040 (31.2) 1,130,678 (26.1) 1,302,761 (33.5) 621,601 (39.4)
 Other medical institution ambulance 174,063 (1.8) 46,428 (1.1) 79,948 (2.1) 47,687 (3.0)
 Other ambulance 643,361 (6.6) 182,670 (4.2) 293,045 (7.5) 167,646 (10.6)
 Police or official transport 4,164 (0.0) 2,458 (0.1) 1,289 (0.0) 417 (0.0)
 Air transport 7,242 (0.1) 3,322 (0.1) 2,915 (0.1) 1,005 (0.1)
 Ambulatory 5,878,374 (60.0) 2,951,626 (68.1) 2,196,923 (56.4) 729,825 (46.3)
 Other 31,650 (0.3) 11,606 (0.3) 12,357 (0.3) 7,687 (0.5)
 Unknown 9,171 (0.1) 4,096 (0.1) 3,576 (0.1) 1,499 (0.1)
Final KTAS scorea)
 1 259,813 (2.7) 72,550 (1.7) 110,278 (2.8) 76,985 (4.9)
 2 817,910 (8.3) 313,137 (7.2) 348,855 (9.0) 155,918 (9.9)
 3 4,161,632 (42.5) 1,733,096 (40.0) 1,727,778 (44.4) 700,758 (44.4)
 4–5 3,643,078 (37.2) 1,796,568 (41.5) 1,343,903 (34.5) 502,607 (31.9)
 Other or unknown 920,632 (9.4) 417,533 (9.6) 362,000 (9.3) 141,099 (8.9)
Severe illness diagnosis 2,083,652 (21.3) 739,926 (17.1) 916,015 (23.5) 427,711 (27.1)
ED length of stay
 Mean±SD (min) 269.1±425.5 242.9±402.7 287.0±439.4 297.1±447.1
 Median (IQR) (min) 148.0 (73-287) 131.0 (60-257) 161.0 (83-307) 170.0 (88-319)
 0–6 hr 7,955,429 (81.2) 3,622,027 (83.6) 3,094,331 (79.5) 1,239,071 (78.6)
 6–12 hr 1,106,944 (11.3) 425,379 (9.8) 479,319 (12.3) 202,246 (12.8)
 12–24 hr 487,875 (5.0) 187,951 (4.3) 209,448 (5.4) 90,476 (5.7)
 ≥24 hr 232,563 (2.4) 88,314 (2.0) 101,925 (2.6) 42,324 (2.7)
 Unknown 20,254 (0.2) 9,213 (0.2) 7,791 (0.2) 3,250 (0.2)
ED disposition
 Discharge 5,707,679 (58.2) 2,873,065 (66.3) 2,109,058 (54.2) 725,556 (46.0)
 Admissionb) 3,538,895 (36.1) 1,281,610 (29.6) 1,546,534 (39.7) 710,751 (45.1)
  General wardc) 2,882,209 (81.4) 1,065,378 (83.1) 1,252,382 (81.0) 564,449 (79.4)
  Intensive care unitc) 647,324 (18.3) 213,390 (16.7) 290,159 (18.8) 143,775 (20.2)
 Transfer 348,339 (3.6) 122,682 (2.8) 152,879 (3.9) 72,778 (4.6)
 Hopeless discharge 2,185 (0.0) 458 (0.0) 884 (0.0) 843 (0.1)
 Death 172,644 (1.8) 39,489 (0.9) 71,029 (1.8) 62,126 (3.9)
 Other 19,155 (0.2) 9,254 (0.2) 6,901 (0.2) 3,000 (0.2)
 Unknown 14,168 (0.1) 6,326 (0.1) 5,529 (0.1) 2,313 (0.1)
Hospital disposition
 Discharge 8,437,152 (86.1) 3,923,807 (90.6) 3,287,389 (84.4) 1,225,956 (77.7)
 Transfer 793,333 (8.1) 249,618 (5.8) 361,079 (9.3) 182,636 (11.6)
 Hopeless discharge 4,917 (0.1) 1,347 (0.0) 2,011 (0.1) 1,559 (0.1)
 Death 446,931 (4.6) 114,131 (2.6) 191,416 (4.9) 141,384 (9.0)
 Other 33,001 (0.3) 13,761 (0.3) 13,162 (0.3) 6,078 (0.4)
 Unknown 87,731 (0.9) 30,220 (0.7) 37,757 (1.0) 19,754 (1.3)
Rank Chief complaint
Primary diagnosis
UMLS code No. of patients (%) KCD code No. of patients (%)
1 C0000737 (abdominal pain) 708,435 (7.9) R42 (light headedness) 410,793 (4.2)
2 C0013404 (dyspnea) 654,301 (7.3) A099 (gastroenteritis and colitis of unspecified origin) 276,299 (2.8)
3 C0012833 (dizziness) 598,055 (6.6) J189 (pneumonia, unspecified) 261,002 (2.7)
4 C0015967 (fever) 498,130 (5.5) R1049 (unspecified abdominal pain) 183,187 (1.9)
5 C0004093 (generalized weakness) 370,037 (4.1) I639 (unspecified cerebral infarction) 144,159 (1.5)
6 C0018681 (headache) 268,212 (3.0) R060 (shortness of breath) 128,831 (1.3)
7 C0008031 (chest pain) 234,616 (2.6) R074 (unspecified chest pain) 123,236 (1.3)
8 C0004604 (back pain) 181,981 (2.0) N390 (urinary tract infection, site not specified) 121,634 (1.3)
9 C0019559 (hip pain) 156,580 (1.7) R51 (headache) 111,430 (1.1)
10 C0232493 (epigastric pain) 127,502 (1.4) S0600 (concussion, without open intracranial wound) 107,749 (1.1)
11 C0042963 (vomiting) 100,601 (1.1) R509 (unspecified fever) 105,160 (1.1)
12 C0235710 (chest discomfort) 95,042 (1.1) R53 (chronic debility) 103,442 (1.1)
13 C0039070 (syncope) 92,828 (1.0) K5909 (other and unspecified constipation) 98,206 (1.0)
14 C0011991 (diarrhea) 90,200 (1.0) U071 (COVID-19, virus identified) 89,099 (0.9)
15 C0024031 (low back pain) 88,983 (1.0) Z115 (special screening examination for other viral diseases) 80,432 (0.8)
Table 1. Patient demographics, ED visit characteristics, and outcome by KTAS scores

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

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

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

Data for the “other” category are not presented.

Proportion among total admissions.

Table 2. Patient demographics, ED visit characteristics, and outcome by age group

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

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

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

Data for the “other” category are not presented.

Proportion among total admissions.

Table 3. Fifteen most frequently reported chief complaints by UMLS code and primary diagnoses by KCD code (n=9,803,065)

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