Characteristics of patients who developed ARDS
| No ARDS | ARDS | P value | |
| Demographics | |||
| Age, n (%) | |||
| 16–25 | 536 163 (19.7) | 5109 (17.9) | <0.001 |
| 26–45 | 757 781 (27.8) | 7654 (26.8) | |
| 46–65 | 743 021 (27.3) | 8887 (31.1) | |
| 66–75 | 257 950 (9.5) | 3063 (10.7) | |
| >75 | 428 854 (15.7) | 3884 (13.6) | |
| Male, n (%) | 1 710 390 (62.8) | 21 002 (73.5) | <0.001 |
| Race, n (%) | <0.001 | ||
| White | 1 797 453 (70.4) | 19 879 (72.9) | |
| Black | 411 673 (16.1) | 4525 (16.6) | |
| Hispanic or Latino | 261 519 (10.3) | 2001 (7.3) | |
| Other | 81 848 (3.2) | 859 (3.2) | |
| Insurance, n (%) | <0.001 | ||
| Medicaid | 343 047 (17.4) | 4238 (19.8) | |
| Medicare | 613 508 (31.1) | 6025 (28.1) | |
| Private | 539 732 (27.4) | 6619 (30.9) | |
| Self-pay | 476 434 (24.2) | 4554 (21.2) | |
| Extrathoracic risk factors | |||
| EtOH, n (%) | <0.001 | ||
| Not tested | 1 195 385 (49.4) | 9821 (38.4) | |
| No-confirmed | 741 053 (30.6) | 9387 (36.7) | |
| Below 0.08 | 128 126 (5.3) | 1511 (5.9) | |
| Above 0.08 | 356 037 (14.7) | 4838 (18.9) | |
| Drugs, n (%) | <0.001 | ||
| Not tested | 1 495 965 (68.0) | 10 859 (51.0) | |
| No-confirmed | 340 618 (15.5) | 4472 (21.0) | |
| Yes-prescription | 87 440 (4.0) | 1520 (7.1) | |
| Yes-illegal | 274 913 (12.5) | 4426 (20.8) | |
| Injury Severity Score, mean (SD) | 10.9 (8.7) | 23.3 (13.3) | <0.001 |
| Lowest ED SBP, mean (SD) | 138.7 (28.6) | 130.5 (36.6) | <0.001 |
| Temperature (°C), mean (SD) | 36.5 (1.7) | 36.1 (2.1) | <0.001 |
| GCS motor score, mean (SD) | 5.7 (1.1) | 4.3 (2.2) | <0.001 |
| Thoracic risk factors | |||
| Presence of rib fracture, n (%) | <0.001 | ||
| No rib fracture | 2 330 056 (85.6) | 17 395 (60.1) | |
| 1 rib fracture | 86 130 (3.2) | 1681 (5.9) | |
| 2 rib fractures | 60 549 (2.2) | 1189 (4.2) | |
| 3 rib fractures | 46 196 (1.7) | 784 (2.7) | |
| 4 rib fractures | 48 317 (1.8) | 1229 (4.3) | |
| 5 rib fractures | 26 295 (1.0) | 647 (2.3) | |
| 6 rib fractures | 19 593 (0.7) | 568 (2.0) | |
| 7 rib fractures | 13 873 (0.5) | 491 (1.7) | |
| ≥8 rib fractures | 31 803 (1.2) | 1615 (5.7) | |
| Rib fracture NOS | 46 745 (1.7) | 1759 (6.2) | |
| Flail chest | 14 212 (0.5) | 1239 (4.3) | |
| Trauma-induced lung contusion, n (%) | 151 216 (5.6) | 6182 (21.6) | <0.001 |
| Comorbidities, n (%) | |||
| Alcoholism | 215 944 (8.2) | 4427 (16.5) | <0.001 |
| Bleeding disorder | 117 319 (4.5) | 2264 (8.4) | <0.001 |
| Congestive heart failure | 73 357 (2.8) | 1623 (6.1) | <0.001 |
| Current smoker | 368 726 (14.0) | 3622 (13.5) | 0.02 |
| Diabetes mellitus | 282 705 (10.8) | 3771 (14.1) | <0.001 |
| History of angina within 30 days | 4186 (0.2) | 292 (1.1) | <0.001 |
| History of myocardial infarction | 31 434 (1.2) | 673 (2.5) | <0.001 |
| Hypertension requiring medications | 689 740 (26.2) | 8471 (31.6) | <0.001 |
| Obesity | 125 396 (4.8) | 2415 (9.0) | <0.001 |
| History of respiratory disease | 185 996 (7.1) | 3057 (11.4) | <0.001 |
ARDS, acute respiratory distress syndrome; ED, emergency department; EtOH, preinjury alcohol consumption; GCS, Glasgow Coma Scale; NOS, not otherwise specified; SBP, systolic blood pressure.