| Patient characteristics | ALI | No ALI | p-value |
| Subjects n | 68 | 341 | |
| Demographics | |||
| Age yrs | 68.0 (19.0–96.0) | 68.0 (18.0–97.0) | 0.69 |
| Female | 32 (47) | 154 (45) | 0.77 |
| Predisposing conditions | |||
| Sepsis | 14 (21) | 33(10) | 0.01 |
| Shock | 44 (65) | 120 (35) | <0.001 |
| Trauma | 5 (7) | 13 (4) | 0.19 |
| Pneumonia | 9 (13) | 46 (13) | 0.96 |
| Aspiration | 7 (10) | 12 (4) | 0.015 |
| Pancreatitis | 1 (1) | 3 (1) | 0.65 |
| High-risk surgery | |||
| Elective | 8 (12) | 23 (7) | 0.15 |
| Emergent | 25 (37) | 52 (15) | <0.001 |
| Risk modifiers | |||
| Alcohol | 12 (18) | 14 (4) | <0.001 |
| Smoking | 36 (53) | 139 (41) | 0.06 |
| Hypoalbuminaemia | 7 (10) | 6 (2) | <0.001 |
| Diabetes | 13 (19) | 74 (22) | 0.63 |
| No sepsis | 10 (19) | 56 (18) | 0.95 |
| Sepsis | 3 (21) | 18 (55) | 0.05 |
| Chemotherapy | 1 (1) | 1 (0) | 0.20 |
| Oxygen supplementation >0.35# | 46 (68) | 148 (43) | <0.001 |
| Tachypnoea¶ | 18 (26) | 33 (10) | <0.001 |
Data are presented as mean (interquartile range) or n (%), unless otherwise stated. Missing data: smoking (83% complete), alcohol (93% complete) and serum albumin (7% complete). Missing data were considered as negative. #: >4 L·min−1 nasal cannula; ¶: respiratory rate, 30 breaths·min−1.