Table 1. Patient characteristics according to age category at baseline.
| 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 | |
| Age, years | 52.0 [47.0 to 55.0] | 62.0 [60.0 to 64.0] | 69.0 [67.0 to 71.0] | 75.0 [74.0 to 77.0] | <0.001 |
| Male | 200 (69.7) | 217 (75.9) | 203 (71.7) | 197 (74.1) | 0.370 |
| Height, cm | 178.0 [170.0 to 185.0] | 178 [170.0 to 184.0] | 175.0 [170.0 to 180.0] | 174.0 [168.5 to 180.0] | <0.001 |
| Weight, kg | 90.0 [80.8 to 105.0] | 89.0 [78.2 to 98.0] | 85.0 [75.6 to 92.2] | 82.0 [75.0 to 90.0] | <0.001 |
| Body Mass Index, kg/m2 | 28.9 [26.2 to 32.7] | 27.7 [25.4 to 30.6] | 27.2 [24.8 to 29.7] | 27.0 [24.9 to 29.4] | <0.001 |
| Severity of illness* | |||||
| SAPS II, % (no) | 35.7 (99/277) | 34.3 (92/268) | 33.6 (91/271) | 30.8 (77/250) | |
| *Modified SAPS II | 24.0 [19.0 to 29.0] | 24.0 [19.0 to 31.0] | 24.5 [19.0 to 32.0] | 26.0 [20.0 to 34.0] | 0.361 |
| APACHE II, no (%) | 26.0 (72/277) | 25.4 (68/268) | 17.7 (48/271) | 22.4 (56/250) | |
| *Modified APACHE II | 12.0 [10.0 to 15.0] | 12.0 [9.0 to 15.0] | 15.0 [9.0 to 19.0] | 15.0 [10.0 to 20.0] | 0.026 |
| APACHE IV, no (%) | 45.5 (126/277) | 40.7 (109/268) | 41.7 (113/271) | 36.8 (92/250) | |
| *Modified APACHE IV | 44.0 [37.2 to 55.0] | 44.0 [35.0 to 56.5] | 49.0 [36.8 to 59.2] | 49.0 [34.8 to 62.0] | 0.469 |
| SOFA, no (%) | 53.4 (148/227) | 54.1 (145/268) | 46.5 (126/271) | 44.4 (111/250) | |
| SOFA | 7.0 [5.0 to 8.0] | 7.0 [6.0 to 10.0] | 7.0 [6.0 to 10.0] | 8.0 [7.0 to 12.5] | <0.001 |
| Comorbidities | |||||
| Arterial hypertension | 53 (18.5) | 105 (36.7) | 108 (38.2) | 114 (42.9) | <0.001 |
| Heart failure | 3 (1.0) | 10 (3.5) | 16 (5.7) | 20 (7.5) | <0.001 |
| Diabetes mellitus | 44 (15.3) | 62 (21.7) | 80 (28.3) | 64 (24.1) | 0.002 |
| Chronic kidney disease | 8 (2.8) | 14 (4.9) | 9 (3.2) | 16 (6.0) | 0.204 |
| Baseline creatinine | 71.0 [60.0 to 87.0] | 77.0 [64.0 to 98.0] | 78.0 [63.0 to 98.0] | 84.0 [66.8 to 111.2] | <0.001 |
| Liver cirrhosis | 2 (0.7) | 0 (0.0) | 0 (0.0) | 1 (0.4) | 0.329 |
| Chronic obstructive pulmonary disease | 8 (2.8) | 25 (8.7) | 34 (12.0) | 21 (7.9) | <0.001 |
| Active hematological neoplasia | 3 (1.0) | 5 (1.7) | 4 (1.4) | 4 (1.5) | 0.911 |
| Active solid neoplasia | 3 (1.0) | 7 (2.4) | 8 (2.8) | 10 (3.8) | 0.193 |
| Neuromuscular disease | 4 (1.4) | 0 (0.0) | 2 (0.7) | 2 (0.8) | 0.258 |
| Immunosuppression | 7 (2.4) | 8 (2.8) | 5 (1.8) | 4 (1.5) | 0.710 |
| Previous medication | |||||
| Systemic steroids | 6 (2.1) | 8 (2.8) | 10 (3.5) | 14 (5.3) | 0.216 |
| Inhalation steroids | 34 (11.8) | 37 (12.9) | 33 (11.7) | 21 (7.9) | 0.244 |
| Angiotensin-converting enzyme inhibitor | 25 (8.7) | 45 (15.7) | 62 (21.9) | 57 (21.4) | <0.001 |
| Angiotensin II receptor blocker | 18 (6.3) | 35 (12.2) | 30 (10.6) | 44 (16.5) | 0.002 |
| Beta-blockers | 28 (9.8) | 52 (18.2) | 63 (22.3) | 68 (25.6) | <0.001 |
| Insulin | 16 (5.6) | 22 (7.7) | 21 (7.4) | 19 (7.1) | 0.744 |
| Metformin | 29 (10.1) | 47 (16.4) | 52 (18.4) | 47 (17.7) | 0.020 |
| Statins | 35 (12.2) | 76 (26.6) | 110 (38.9) | 109 (41.0) | <0.001 |
| Calcium channel blockers | 29 (10.1) | 45 (15.7) | 59 (20.8) | 64 (24.1) | <0.001 |
| Transferred under invasive ventilation from another hospital | 59 (20.6) | 53 (18.5) | 48 (17.0) | 41 (15.4) | 0.436 |
| Days between admission and start of invasive ventilation | 0.0 [0.0 to 0.0] | 0.0 [0.0 to 0.0] | 0.0 [0.0 to 0.0] | 0.0 [0.0 to 0.0] | 0.508 |
| Use of non-invasive mechanical ventilation before intubation | 28/259 (10.8) | 14/256 (5.5) | 24/258 (9.3) | 19/236 (8.1) | 0.152 |
| Duration of non-invasive ventilation, hours | 7.0 [2.0 to 23.0] | 7.0 [3.5 to 19.0] | 8.0 [2.8 to 9.5] | 8.0 [1.0 to 17.0] | 1.000 |
| Chest CT-scan performed at baseline | 111/276 (40.2) | 93/270 (34.4) | 78/269 (29.0) | 81/257 (31.5) | 0.023 |
| Percentage lung parenchyma affected | 0.561 | ||||
| 0% | 7/111 (6.3) | 3/93 (3.2) | 3/78 (3.8) | 1/81 (1.2) | |
| 25% | 29/111 (26.1) | 27/93 (29.0) | 29/78 (37.2) | 31/81 (38.3) | |
| 50% | 38/111 (34.2) | 26/93 (28.0) | 21/78 (26.9) | 22/81 (27.2) | |
| 75% | 30/111 (27.0) | 33/93 (35.5) | 19/78 (24.4) | 22/81 (27.2) | |
| 100% | 7/111 (6.3) | 4/93 (4.3) | 6/78 (7.7) | 5/81 (6.2) | |
| Chest x-ray performed at baseline | 136/162 (84.0) | 152/176 (86.4) | 157/185 (84.9) | 157/176 (89.2) | 0.506 |
| Quadrants affected | 0.810 | ||||
| 1 | 13 (9.8) | 12 (7.8) | 8 (5.0) | 9 (5.8) | |
| 2 | 32 (24.1) | 37 (24.0) | 38 (23.8) | 32 (20.8) | |
| 3 | 34 (25.6) | 39 (25.3) | 45 (28.1) | 50 (32.5) | |
| 4 | 54 (40.6) | 66 (42.9) | 69 (43.1) | 63 (40.9) | |
| Laboratory tests | |||||
| pH | 7.4 [7.3 to 7.4] | 7.4 [7.3 to 7.4] | 7.4 [7.3 to 7.4] | 7.3 [7.3 to 7.4] | <0.001 |
| PaO2 | 10.7 [9.2 to 14.2] | 10.3 [8.8 to 12.6] | 10.9 [9.5 to 13.3] | 11.2 [9.7 to 13.3] | 0.008 |
| SaO2 | 95.0 [93.0 to 97.4] | 94.2 [92.0 to 96.8] | 95.0 [93.0 to 97.0] | 95.0 [93.0 to 97.0] | 0.030 |
| PaCO2 | 5.6 [4.9 to 6.5] | 5.9 [5.0 to 6.9] | 6.1 [5.3 to 7.1] | 5.9 [5.0 to 6.9] | 0.003 |
| Lactate | 1.1 [0.9 to 1.4] | 1.1 [0.9 to 1.4] | 1.2 [0.9 to 1.5] | 1.2 [1.0 to 1.6] | 0.002 |
| Worst PaO2/FiO2 ratio, mm Hg | 126.6 [94.7 to 164.5] | 117.9 [91.8 to 160.3] | 120.2 [96.1 to 157.3] | 126.2 [97.4 to 161.6] | 0.401 |
| Need for advanced support | |||||
| Continuous sedation | 277/287 (96.5) | 276/286 (96.5) | 267/277 (95.0) | 253/263 (95.1) | 0.691 |
| Need for vasopressor use | 198/287 (69.0) | 223/286 (78.0) | 225/281 (80.1) | 217/266 (81.6) | 0.002 |
| Need for inotropic use | 6/287 (2.1) | 6/286 (2.1) | 16/281 (5.7) | 17/266 (6.4) | 0.009 |
| Fluid balance, mL | 418.0 [-126.0 to 1206.0] | 513.0 [-26.3 to 1209.0] | 456.1 [-25.5 to 1252.8] | 780.0 [144.0 to 1557.0] | 0.001 |
| Urine output, mL | 875.0 [511.2 to 1377.5] | 657.0 [350.0 to 1120.0] | 720.0 [370.0 to 1165.0] | 505.0 [255.0 to 877.5] | <0.001 |
Data presented as median with interquartile range [25th to 75th quartile] or n (%). *Age component is removed from the APACHE and SAPS Score. *Total numbers are different because different scores were used in the participating hospitals.
SAPS, Simplified Acute Physiology Score; APACHE, Acute Physiology and Chronic Health Evaluation; SOFA, Sequential Organ Failure Assessment; CT, Computed Tomography.