Table 3. Clinical outcome according to age group.
| Age 22 to 57 years (n = 287) | Age 58 to 65 years (n = 286) | Age 66 to 72 years (n = 283) | Age 73 to 85 years (n = 266) | P value | |
| 28-day mortality | 36/281 (12.8) | 59/279 (21.1) | 100/279 (35.8) | 123/263 (46.8) | <0.001 |
| 90-day mortality | 46/255 (18.0) | 72/251 (28.7) | 120/267 (44.9) | 145/242 (59.9) | <0.001 |
| In hospital mortality | 43/259 (16.6) | 71/256 (27.7) | 113/255 (44.3) | 140/252 (55.6) | <0.001 |
| ICU mortality | 42/277 (15.2) | 71/278 (25.5) | 110/274 (40.1) | 133/262 (50.8) | <0.001 |
| Length of hospital stay, days | 24.0 [17.0 to 33.0] | 26.0 [16.0 to 41.0] | 22.0 [14.0 to 39.0] | 21.5 [10.0 to 36.0] | 0.008 |
| Length of hospital stay in survivors, days | 25.0 [18.5 to 35.5] | 30.0 [20.0 to 46.5] | 32.5 [20.3 to 49.8] | 33.0 [25.8 to 52.0] | <0.001 |
| Length of ICU stay, days | 15.0 [10.0 to 23.0] | 17.0 [10.0 to 30.0] | 16.0 [8.3 to 26.0] | 14.0 [7.0 to 25.0] | 0.037 |
| Length of ICU stay in survivors, days | 15.0 [10.0 to 22.8] | 20.0 [12.0 to 31.0] | 18.0 [10.0 to 34.0] | 20.0 [13.0 to 38.0] | <0.001 |
| Ventilator-free days at day 28 | 13.0 [0.0 to 19.0] | 4.0 [0.0 to 17.0] | 0.0 [0.0 to 14.2] | 0.0 [0.0 to 9.7] | <0.001 |
| Duration of ventilation, days | 13.0 [9.0 to 21.0] | 15.0 [9.0 to 26.0] | 15.0 [8.0 to 24.0] | 13.0 [6.0 to 22.0] | 0.023 |
| Duration of ventilation in survivors, days* | 13.0 [8.0 to 21.2] | 17.0 [10.0 to 28.3] | 17.0 [10.0 to 31.0] | 19.0 [12.0 to 34.0] | <0.001 |
| Tracheostomy* | 35/283 (12.4) | 62/284 (21.8) | 48/280 (17.1) | 45/265 (17.0) | 0.029 |
| Reintubation* | 32/282 (11.3) | 42/284 (14.8) | 33/278 (11.9) | 33/264 (12.5) | 0.631 |
| Pneumothorax* | 2/283 (0.7) | 3/275 (1.1) | 2/267 (0.7) | 2/259 (0.8) | 0.970 |
| Thrombotic complications*& | 72/287 (25.1) | 95/286 (33.2) | 74/283 (26.1) | 78/266 (29.3) | 0.135 |
| Pulmonary embolism | 55/287 (19.2) | 75/286 (26.2) | 61/283 (21.6) | 58/266 (21.8) | 0.236 |
| Deep vein thrombosis | 17/287 (5.9) | 20/286 (7.0) | 9/283 (3.2) | 11/266 (4.1) | 0.156 |
| Ischemic stroke | 3/287 (1.0) | 10/286 (3.5) | 8/283 (2.8) | 10/266 (3.8) | 0.148 |
| Myocardial infarction | 2/287 (0.7) | 0/286 (0.0) | 7/283 (2.5) | 7/266 (2.6) | 0.007 |
| Systemic arterial thrombosis | 1/287 (0.3) | 1/286 (0.3) | 2/283 (0.7) | 0/266 (0.0) | 0.805 |
| Acute kidney injury* | 89/287 (31.0) | 140/285 (49.1) | 126/281 (44.8) | 141/265 (53.2) | <0.001 |
| Need for renal replacement* | 35/287 (12.2) | 62/286 (21.7) | 57/283 (20.1) | 51/266 (19.2) | 0.013 |
| Adjunctive therapies refractory hypoxemia** | 162/284 (57.0) | 174/282 (61.7) | 159/282 (56.4) | 152/265 (57.4) | 0.563 |
| Prone positioning | 156/284 (54.9) | 169/282 (59.9) | 155/282 (55.0) | 145/265 (54.7) | 0.533 |
| Alveolar recruitment maneuver | 15/242 (6.2) | 16/239 (6.7) | 18/239 (7.5) | 15/214 (7.0) | 0.946 |
| Other adjunctive therapies** | 156/287 (54.4) | 134/286 (46.9) | 143/283 (50.5) | 104/266 (39.1) | 0.003 |
| Neuromuscular blocking agents | 156/287 (54.4) | 133/286 (46.5) | 141/283 (49.8) | 104/266 (39.1) | 0.003 |
| Extracorporeal membrane oxygenation | 7/285 (2.5) | 2/282 (0.7) | 2/278 (0.7) | 1/262 (0.4) | 0.142 |
Data presented as median with interquartile range [25th to 75th quartile] or n (%). Totals are different due to missing data. *Assessed at day 28. **Assessed in the first four days of ventilation. &One could have more than one thrombotic complication. Total numbers are different because of missing or unmeasured values.
ICU, Intensive Care Unit.