Table 1.
Description of ARDS patients in the derivation dataset, the validation dataset, and the combined dataset
| Variable | Derivation dataset (N = 520) | Validation dataset (N = 356) | Combined dataset (N = 876) | P |
|---|---|---|---|---|
| Age | 56.71 ± 17.54 | 58.54 ± 18.10 | 57.45 ± 17.78 | 0.1362 |
| Gender | ||||
| Male | 329 (63.27%) | 221 (62.08%) | 550 (62.79%) | 0.7203 |
| Female | 191 (36.73%) | 135 (37.92%) | 326 (37.21%) | |
| Ethnicity | ||||
| White | 470 (90.38%) | 318 (89.33%) | 788 (89.95%) | 0.2999 |
| Black | 20 (3.85%) | 20 (5.62%) | 40 (4.57%) | |
| Hispanic | 22 (4.23%) | 13 (3.65%) | 35 (4.00%) | |
| Asian | 7 (1.35%) | 2 (0.56%) | 9 (1.03%) | |
| Other | 1 (0.19%) | 3 (0.84%) | 4 (0.46%) | |
| Body mass index | 28.82 ± 8.93 | 28.55 ± 9.19 | 28.71 ± 9.04 | 0.6750 |
| Smoking status | ||||
| Never | 143 (32.06%) | 104 (33.88%) | 247 (32.80%) | 0.2484 |
| Former | 129 (28.92%) | 101 (32.90%) | 230 (30.54%) | |
| Current | 174 (39.01%) | 102 (33.22%) | 276 (36.65%) | |
| Alcohol abuse within 12 months | 90 (17.31%) | 57 (16.01%) | 147 (16.78%) | 0.6140 |
| Prednisone prior ICU | 36 (6.92%) | 25 (7.02%) | 61 (6.96%) | 0.9547 |
| Vasopressors within 24 h | 391 (75.19%) | 258 (72.47%) | 649 (74.09%) | 0.3668 |
| Patient source | ||||
| Operating room | 69 (13.27%) | 46 (12.92%) | 115 (13.13%) | 0.6865 |
| Recovery room | 4 (0.77%) | 2 (0.56%) | 6 (0.68%) | |
| Emergency room | 182 (35.00%) | 126 (35.39%) | 308 (35.16%) | |
| Floor | 130 (25.00%) | 104 (29.21%) | 234 (26.71%) | |
| Other special care unit | 23 (4.42%) | 12 (3.37%) | 35 (4.00%) | |
| Other hospital floor | 112 (21.54%) | 66 (18.54%) | 178 (20.32%) | |
| ICU readmission | 52 (10.00%) | 38 (10.67%) | 90 (10.27%) | 0.7469 |
| ARDS risk factors | ||||
| Bacteremia | 90 (17.31%) | 50 (14.04%) | 140 (15.98%) | 0.1955 |
| Sepsis | 449 (86.35%) | 307 (86.24%) | 756 (86.30%) | 0.9628 |
| Septic shock | 360 (69.23%) | 235 (66.01%) | 595 (67.92%) | 0.3160 |
| Pneumonia | 393 (75.58%) | 258 (72.47%) | 651 (74.32%) | 0.3015 |
| Multiple fractures | 20 (3.85%) | 14 (3.93%) | 34 (3.88%) | 0.9481 |
| Pulmonary contusion | 23 (4.42%) | 20 (5.62%) | 43 (4.91%) | 0.4214 |
| Aspiration | 55 (10.58%) | 32 (8.99%) | 87 (9.93%) | 0.4402 |
| Multiple transfusion | 39 (7.50%) | 32 (8.99%) | 71 (8.11%) | 0.4278 |
| ARDS onset day | ||||
| 0 | 242 (46.54%) | 139 (39.04%) | 381 (43.49%) | 0.0966 |
| 1 | 135 (25.96%) | 87 (24.44%) | 222 (25.34%) | |
| 2 | 53 (10.19%) | 55 (15.45%) | 108 (12.33%) | |
| 3 | 37 (7.12%) | 30 (8.43%) | 67 (7.65%) | |
| 4 | 27 (5.19%) | 20 (5.62%) | 47 (5.37%) | |
| 5 | 13 (2.50%) | 16 (4.49%) | 29 (3.31%) | |
| 6 | 13 (2.50%) | 9 (2.53%) | 22 (2.51%) | |
| Lung injury score | 2.53 ± 0.76 | 2.44 ± 0.81 | 2.50 ± 0.78 | 0.0897 |
| APACHE III score | 76.63 ± 25.26 | 74.37 ± 22.42 | 75.71 ± 24.16 | 0.1650 |
| ICU duration days | 13.00 (7.00–21.00) | 14.00 (8.00–21.00) | 13.00 (8.00–21.00) | 0.2388 |
| ICU 28-day ventilator-free days | 2.00 (0.00–4.00) | 2.00 (0.00–4.00) | 2.00 (0.00–4.00) | 0.5795 |
Normal and non-normal distributed continuous variables were described using mean ± standard and median (25th quantile–75th quantile), respectively. ARDS onset within 24 h of ICU admission was defined as day 0, and 24–48 h was day 1, etc. ARDS patients between two phases are comparable if P > 0.05
APACHE Acute Physiology and Chronic Health Evaluation