Table 1.
General characteristics of the study population and the propensity score-matched samples. Continuous variables were compared using the independent t-test, and categorical variables were compared using the chi-square test.
| Original study population | P value | Matched samples | P value | |||
|---|---|---|---|---|---|---|
| RTC (N = 27108) | EMC (N = 1000026) | RTC (N = 26694) | EMC (N = 26694) | |||
| Male sex | 17382 (64.1) | 566882 (56.7) | <0.001 | 17060 (63.9) | 15838 (59.3) | <0.001 |
| Age | 46.7 ± 19.1 | 46.3 ± 18.8 | 0.001 | 46.6 ± 19.1 | 46.8 ± 19.5 | 0.280 |
| Insurance type | <0.001 | 0.001 | ||||
| National health | 16520 (60.9) | 738396 (73.8) | 16468 (61.7) | 16789 (62.9) | ||
| Automobile | 6917 (25.5) | 168181 (16.8) | 6728 (25.2) | 6487 (24.3) | ||
| Occupational hazard | 548 (2.0) | 5960 (0.6) | 492 (1.8) | 521 (2.0) | ||
| Health aid type 1 | 821 (3.0) | 32408 (3.2) | 817 (3.1) | 860 (3.2) | ||
| Health aid type 2 | 248 (0.9) | 8922 (0.9) | 246 (0.9) | 275 (1.0) | ||
| Others | 46159 (4.6) | 2054 (7.6) | 1943 (7.3) | 1762 (6.6) | ||
| Mechanism | <0.001 | <0.001 | ||||
| Traffic car | 4487 (16.6) | 127319 (12.7) | 4424 (16.6) | 4071 (15.3) | ||
| Traffic bicycle | 864 (3.2) | 19894 (2.0) | 846 (3.2) | 909 (3.4) | ||
| Traffic motorcycle | 1626 (6.0) | 28134 (2.8) | 1555 (5.8) | 1543 (5.8) | ||
| Traffic others | 1845 (6.8) | 33091 (3.3) | 1745 (6.5) | 1683 (6.3) | ||
| Fall from heights | 2526 (9.3) | 51973 (5.2) | 2401 (9.0) | 2400 (9.0) | ||
| Fall from level | 5062 (18.7) | 201653 (20.2) | 5059 (19.0) | 5324 (19.9) | ||
| Struck by person or object | 5177 (19.1) | 179780 (18.0) | 5159 (19.3) | 5297 (19.8) | ||
| Firearm, cut, or pierce | 3776 (13.9) | 176449 (17.6) | 3766 (14.1) | 3693 (13.8) | ||
| Machine | 392 (1.4) | 14974 (1.5) | 386 (1.4) | 359 (1.3) | ||
| Others | 1353 (5.0) | 166759 (16.7) | 1353 (5.1) | 1415 (5.3) | ||
| Intent | <0.001 | <0.001 | ||||
| Accidental-unintentional | 25108 (92.6) | 926081 (92.6) | 24728 (92.6) | 24794 (92.9) | ||
| Intentional or self-harm | 511 (1.9) | 9032 (0.9) | 495 (1.9) | 557 (2.1) | ||
| Violence or assault | 1186 (4.4) | 46437 (4.6) | 287 (1.1) | 160 (0.6) | ||
| Others | 303 (1.1) | 18476 (1.8) | 1184 (4.4) | 1183 (4.4) | ||
| Mode of transport | <0.001 | 0.044 | ||||
| Ambulance | 13394 (49.4) | 289841 (29.0) | 12988 (48.7) | 12754 (47.8) | ||
| Others | 13714 (50.6) | 710185 (71.0) | 13706 (51.3) | 13940 (52.2) | ||
| Respiratory rate (min−1) | 19.2 ± 2.6 | 19.2 ± 2.2 | 0.268 | 19.1 ± 2.5 | 19.4 ± 3.2 | <0.000 |
| Pulse oxygen saturation (%) | 97.3 ± 4.0 | 97.9 ± 3.9 | <0.001 | 97.4 ± 3.7 | 97.6 ± 4.2 | 0.001 |
| Body temperature (°C) | 36.6 ± 0.5 | 36.5 ± 0.6 | <0.001 | 36.6 ± 0.6 | 36.6 ± 0.5 | 0.000 |
| Systolic blood pressure (mmHg) | 135.0 ± 24.0 | 134.8 ± 21.6 | 0.085 | 135.2 ± 23.7 | 135.5 ± 24.7 | 0.134 |
| Heart rate (min−1) | 85.3 ± 15.5 | 82.8 ± 13.6 | <0.001 | 85.0 ± 15.2 | 84.9 ± 15.6 | 0.395 |
| Responsiveness | <0.001 | 0.173 | ||||
| Alert | 24940 (92.0%) | 988403 (98.8%) | 24835 (93.0) | 24716 (92.6) | ||
| Response to voice | 1176 (4.3%) | 7826 (0.8%) | 1021 (3.8) | 1059 (4.0) | ||
| Response to pain | 789 (2.9%) | 3261 (0.3%) | 660 (2.5) | 733 (2.7) | ||
| Unresponsive | 203 (0.7%) | 536 (0.1%) | 178 (0.7) | 186 (0.7) | ||
| SRR of primary diagnosis | 0.99 ± 0.02 | 1.00 ± 0.01 | <0.001 | 0.99 ± 0.02 | 0.99 ± 0.02 | 0.041 |
| KTAS | <0.001 | <0.001 | ||||
| 1 | 517 (1.9) | 1064 (0.1) | 416 (1.0) | 430 (1.6) | ||
| 2 | 3684 (13.6) | 15387 (1.5) | 3372 (12.6) | 3527 (13.2) | ||
| 3 | 5160 (19.0) | 154128 (15.4) | 5159 (19.3) | 4622 (17.3) | ||
| 4 | 14459 (53.3) | 669423 (66.9) | 14459 (54.2) | 14830 (55.6) | ||
| 5 | 3288 (12.1) | 160024 (16.0) | 3288 (12.3) | 3285 (12.3) | ||
| Anatomic locations of injury | ||||||
| Head injury | 12874 (47.5) | 311749 (31.2) | <0.001 | 12528 (46.9) | 12707 (47.6) | 0.123 |
| Neck injury | 2532 (9.3) | 80550 (8.1) | <0.001 | 2478 (9.3) | 2043 (7.7) | <0.001 |
| Chest | 4341 (16.0) | 68075 (6.8) | <0.001 | 4030 (15.1) | 3614 (13.5) | <0.001 |
| Abdomen or pelvis | 3834 (14.1) | 100413 (10.0) | <0.001 | 3630 (13.6) | 3122 (11.7) | <0.001 |
| Upper limb | 6548 (24.2) | 273027 (27.3) | <0.001 | 6426 (24.1) | 6171 (23.1) | 0.010 |
| Lower limb | 5311 (19.6) | 213899 (21.4) | <0.001 | 5213 (19.5) | 4870 (18.2) | <0.001 |
| Unspecified | 3108 (11.5) | 174816 (17.5) | <0.001 | 3105 (11.6) | 3283 (12.3) | 0.018 |
| Number of involved anatomic locations of injury | 1.3 ± 1.0 | 1.0 ± 0.8 | <0.001 | 1.3 ± 1.0 | 1.2 ± 0.9 | <0.001 |
| Disposition from the ED | <0.001 | <0.001 | ||||
| Admission to ICU | 3830 (14.1) | 10462 (1.0) | 3471 (13.0) | 1819 (6.8) | ||
| Admission to ward | 4304 (15.9) | 4304 (15.9) | 4268 (16.0) | 3561 (13.3) | ||
| Admission to other units | 0 (0.0) | 22 (0.0) | 0 (0.0) | 1 (0.0) | ||
| Discharge | 18864 (69.6) | 872682 (87.3) | 18859 (70.7) | 21107 (79.1) | ||
| Hopeless discharge | 1 (0.0) | 24 (0.0) | 1 (0.0) | 3 (0.0) | ||
| Death | 31 (0.1) | 253 (0.0) | 17 (0.1) | 100 (0.4) | ||
| Others | 70 (0.3) | 3536 (0.4) | 70 (0.3) | 102 (0.4) | ||
RTC: regional trauma center; EMC: emergency medical center; SRR: survival risk ratio; KTAS: Korean Triage and Acuity Scale.