Table 1 Baseline patients characteristics in the unmatched and propensity score-matched groups
| Â | Unmatched groups | Matched groups | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
HEMS | GEMS | SD, % | HEMS | GEMS | SD, % | |||||
n = 4128 | (%) | n = 17158 | (%) | n = 3980 | (%) | n = 3980 | (%) | |||
Age, years | ||||||||||
 15 - 55 | 1586 | (38.4) | 6923 | (40.3) | 2.5 | 1536 | (38.6) | 1516 | (38.1) | -2.3 |
 56 - 64 | 708 | (17.2) | 2740 | (16.0) | 4.3 | 681 | (17.1) | 697 | (17.5) | 4.1 |
  ≥ 65 | 1834 | (44.4) | 7495 | (43.7) | -5.8 | 1763 | (44.3) | 1767 | (44.4) | -0.8 |
Sex male | 3143 | (76.1) | 11906 | (69.4) | 16.4 | 3016 | (75.8) | 3039 | (76.4) | -1.2 |
Systolic blood pressure, mm Hga | ||||||||||
  < 90 | 318 | (7.7) | 1120 | (6.5) | 5.9 | 309 | (7.8) | 315 | (7.9) | 2.7 |
 90 to 109 | 444 | (10.8) | 2078 | (12.1) | -2.6 | 436 | (11.0) | 456 | (11.5) | 1.0 |
  ≥ 110 | 2146 | (52.0) | 10614 | (61.9) | -23.9 | 2107 | (52.9) | 2105 | (52.9) | -1.2 |
 missing | 1220 | (29.6) | 3346 | (19.5) | 26.0 | 1128 | (28.3) | 1104 | (27.7) | -0.9 |
Heart rate, beats/mina | ||||||||||
  < 60 | 228 | (5.5) | 817 | (4.8) | 3.6 | 221 | (5.6) | 241 | (6.1) | -2.9 |
 60 to 99 | 2048 | (49.6) | 10144 | (59.1) | -21.8 | 2015 | (50.6) | 2109 | (53.0) | 1.2 |
  ≥ 100 | 851 | (20.6) | 3862 | (22.5) | -2.7 | 835 | (21.0) | 746 | (18.7) | 1.2 |
missing | 1001 | (24.2) | 2335 | (13.6) | 29.0 | 909 | (22.8) | 884 | (22.2) | -1.0 |
Respiratory rate, breaths/mina | ||||||||||
  < 10 or > 29 | 781 | (18.9) | 3030 | (15.0) | 10.2 | 770 | (19.3) | 743 | (18.7) | 0.8 |
 10 to 29 | 1818 | (44.0) | 13175 | (65.3) | -42.5 | 1805 | (45.4) | 1822 | (45.8) | -0.6 |
 missing | 1529 | (37.0) | 3971 | (19.7) | 38.3 | 1405 | (35.3) | 1415 | (35.6) | 0.2 |
Japan Coma Scalea | ||||||||||
 Grade 0 (alert) | 913 | (22.1) | 4453 | (26.0) | -11.1 | 912 | (22.9) | 925 | (23.2) | 0.2 |
 Grade 1 (delirium) | 925 | (22.4) | 5443 | (31.7) | -21.5 | 924 | (23.2) | 946 | (23.8) | 0.7 |
 Grade 2 (sommolence) | 422 | (10.2) | 1788 | (10.4) | 0.7 | 420 | (10.6) | 398 | (10.0) | 2.6 |
 Grade 3 (coma) | 901 | (21.8) | 4185 | (24.4) | -3.4 | 899 | (22.6) | 887 | (22.3) | -2.6 |
 missing | 967 | (23.4) | 1289 | (7.5) | 43.9 | 825 | (20.7) | 824 | (20.7) | 0.0 |
Preexisting medical conditions | ||||||||||
 Neurological diseases | 373 | (9.0) | 2367 | (13.8) | -18.6 | 371 | (9.3) | 343 | (8.6) | 0.3 |
 Cardiovascular diseases | 892 | (21.6) | 3676 | (21.4) | -6.4 | 858 | (21.6) | 853 | (21.4) | 1.2 |
 Respiratory disease | 180 | (4.4) | 589 | (3.4) | 3.6 | 170 | (4.3) | 165 | (4.1) | 0.5 |
 Digestive diseases | 274 | (6.6) | 1231 | (7.2) | -5.0 | 268 | (6.7) | 261 | (6.6) | 2.9 |
 Metabolic disease | 407 | (9.9) | 1771 | (10.3) | -5.2 | 393 | (9.9) | 386 | (9.7) | 0.7 |
 Others | 327 | (7.9) | 1116 | (6.5) | 0.7 | 301 | (7.6) | 271 | (6.8) | 0.0 |
Mechanism of injury | ||||||||||
 Automobile crash | 815 | (19.7) | 2085 | (12.2) | 23.8 | 752 | (18.9) | 756 | (19.0) | 0.0 |
 Motorcycle crash | 618 | (15.0) | 2613 | (15.2) | 3.2 | 608 | (15.3) | 631 | (15.9) | -1.4 |
 Bicycle crash | 270 | (6.5) | 2129 | (12.4) | -15.9 | 270 | (6.8) | 271 | (6.8) | 1.2 |
 Pedestrian traffic accident | 294 | (7.1) | 1559 | (9.1) | -3.9 | 289 | (7.3) | 294 | (7.4) | 0.0 |
 Other vehicle | 44 | (1.1) | 122 | (0.7) | 4.5 | 41 | (1.0) | 40 | (1.0) | 1.0 |
 Fall from high place or Stairs | 1418 | (34.4) | 6366 | (37.1) | 1.5 | 1391 | (34.9) | 1366 | (34.3) | -0.4 |
 Machine injury | 61 | (1.5) | 98 | (0.6) | 9.3 | 50 | (1.3) | 47 | (1.2) | -0.9 |
 Falling object or Explosion | 100 | (2.4) | 283 | (1.6) | 6.7 | 98 | (2.5) | 89 | (2.2) | 0.0 |
 Compression injury | 175 | (4.2) | 368 | (2.1) | 13.1 | 155 | (3.9) | 165 | (4.1) | 1.1 |
 Train | 16 | (0.4) | 163 | (0.9) | -5.2 | 16 | (0.4) | 15 | (0.4) | 0.0 |
 Sports | 96 | (2.3) | 182 | (1.1) | 10.5 | 91 | (2.3) | 91 | (2.3) | 0.7 |
 Other blunt injury | 90 | (2.2) | 322 | (1.9) | 3.7 | 88 | (2.2) | 98 | (2.5) | -0.7 |
 Penetrating | 62 | (1.5) | 336 | (2.0) | -2.4 | 62 | (1.6) | 55 | (1.4) | 0.0 |
 missing | 69 | (1.7) | 532 | (3.1) | -7.8 | 69 | (1.7) | 62 | (1.6) | 0.0 |
Injury distribution with AIS ≥ 3 | ||||||||||
 Head | 1963 | (47.6) | 9357 | (54.5) | -18.9 | 1916 | (48.1) | 1902 | (47.8) | -1.0 |
 Face | 84 | (2.0) | 263 | (1.5) | 3.9 | 81 | (2.0) | 76 | (1.9) | 0.0 |
 Neck | 24 | (0.6) | 115 | (0.7) | -1.4 | 24 | (0.6) | 21 | (0.5) | 1.4 |
 Chest | 2294 | (55.6) | 8183 | (47.7) | 22.8 | 2197 | (55.2) | 2153 | (54.1) | 0.0 |
 Abdomen | 552 | (13.4) | 1686 | (9.8) | 13.7 | 521 | (13.1) | 512 | (12.9) | -0.3 |
 Spine | 916 | (22.2) | 2969 | (17.3) | 11.9 | 862 | (22.5) | 862 | (21.7) | 1.2 |
 Extremity | 1208 | (29.3) | 4270 | (24.9) | 13.7 | 1144 | (28.7) | 1092 | (27.4) | 0.7 |
 Skin | 8 | (0.2) | 26 | (0.2) | 3.3 | 7 | (0.2) | 8 | (0.2) | 0.6 |
Injury Severity Score | ||||||||||
 16 to 24 | 1792 | (43.4) | 8685 | (50.6) | -19.7 | 1750 | (44.0) | 1817 | (45.7) | -4.4 |
 25 to 34 | 1421 | (34.4) | 5700 | (33.2) | 5.3 | 1370 | (34.4) | 1359 | (34.1) | 2.9 |
  ≥ 35 | 915 | (22.2) | 2773 | (16.2) | 19.2 | 860 | (21.6) | 804 | (20.2) | 2.0 |
Accident day | ||||||||||
 Working day | 2876 | (69.7) | 12343 | (71.9) | -5.3 | 2780 | (69.8) | 2745 | (69.0) | 1.9 |
 Weekend | 1252 | (30.3) | 4815 | (28.1) | 5.3 | 1200 | (30.2) | 1235 | (31.0) | -1.9 |