Table 1.
Baseline characteristics of the patients according to the categories of age and the clusters identified
| Age > 65 years (n = 1825) |
Age ≤ 65 years (n = 2079) |
p value | Cluster 1 (n = 976) |
Cluster 2 (n = 2346) |
p value | |
|---|---|---|---|---|---|---|
| Age (years) | 73.6 (69–78.4) | 53.3 (42.7–59.9) | < 0.001 | 64.7 (53.2–74.1) | 63.6 (52.2–72.6) | 0.038 |
| Female gender—no (%)* | 700 (38.4) | 795 (38.2) | 0.947 | 334 (34.2) | 927 (39.5) | 0.004 |
| Weight (kg) | 80 (67–91) | 80 (67–99) | < 0.001 | 81 (70–97) | 78 (65–93) | < 0.001 |
| APACHE II | 23 (19–28) | 20 (15–25) | < 0.001 | 19 (15–24) | 23 (18–29) | < 0.001 |
| Without age* | 18 (13–23) | 18 (13–23) | 0.885 | 15 (11–20) | 19 (15–25) | < 0.001 |
| Time to randomization (h) | 4.7 (1.9–8.6) | 4.5 (1.8–8.7) | 0.739 | 5.5 (2.5–9.6) | 4.5 (2–8.5) | < 0.001 |
| Dexmedetomidine group—no (%) | 913 (50) | 1035 (49.8) | 0.898 | 488 (50) | 1165 (49.7) | 0.879 |
| Diabetes with insulin—no (%) | 185 (10.1) | 205 (9.9) | 0.789 | 61 (6.2) | 246 (10.5) | < 0.001 |
| Type of admission—no (%)* | 0.123 | < 0.001 | ||||
| Non-operative | 1292 (70.8) | 1487 (71.5) | 11 (1.1) | 2343 (99.9) | ||
| Elective surgery | 172 (9.4) | 159 (7.6) | 309 (31.7) | 0 (0) | ||
| Emergency surgery | 361 (19.8) | 433 (20.8) | 656 (67.2) | 3 (0.1) | ||
| Admission diagnosis—no (%)* | < 0.001 | < 0.001 | ||||
| Sepsis | 1174 (64.3) | 1321 (63.5) | 411 (42.1) | 1706 (72.7) | ||
| Respiratory | 203 (11.1) | 245 (11.8) | 63 (6.5) | 304 (13) | ||
| Gastrointestinal | 101 (5.5) | 105 (5.1) | 115 (11.8) | 57 (2.4) | ||
| Cardiovascular | 276 (15.1) | 212 (10.2) | 301 (30.8) | 151 (6.4) | ||
| Trauma | 33 (1.8) | 119 (5.7) | 61 (6.2) | 66 (2.8) | ||
| Neurological | 6 (0.3) | 18 (0.9) | 0 (0) | 20 (0.9) | ||
| Other | 32 (1.8) | 59 (2.8) | 25 (2.6) | 42 (1.8) | ||
| ICU source of admission—no (%)* | < 0.001 | < 0.001 | ||||
| Emergency room | 479 (26.2) | 724 (34.8) | 2 (0.2) | 1012 (43.1) | ||
| Ward | 643 (35.2) | 567 (27.3) | 3 (0.3) | 1011 (43.1) | ||
| Transferred from another hospital | 184 (10.1) | 227 (10.9) | 40 (4.1) | 323 (13.8) | ||
| Operating room | 519 (28.4) | 561 (27) | 931 (95.4) | 0 (0) | ||
| PaO2/FiO2 ratio (mmHg)* | 192 (132–272.2) | 206.3 (136.9–302.9) | < 0.001 | 249.5 (176–340) | 182.7 (125–260) | < 0.001 |
| Sedatives and opioids—no (%) | ||||||
| Opioids*,a | 1290 (74.3) | 1529 (78) | 0.009 | 715 (73.3) | 1789 (76.3) | 0.070 |
| Propofol* | 1442 (83) | 1549 (79) | 0.002 | 898 (92) | 1791 (76.3) | < 0.001 |
| Midazolam* | 472 (27.2) | 690 (35.2) | < 0.001 | 145 (14.9) | 900 (38.4) | < 0.001 |
| Ketamine* | 112 (6.4) | 123 (6.3) | 0.840 | 36 (3.7) | 180 (7.7) | < 0.001 |
| Dexmedetomidine* | 30 (1.7) | 48 (2.4) | 0.137 | 5 (0.5) | 59 (2.5) | < 0.001 |
| Clinical outcomes | ||||||
| 90-day mortality—no (%) | 700 (38.4) | 435 (20.9) | < 0.001 | 240 (24.6) | 731 (31.2) | < 0.001 |
| Coma- and delirium-free days | 22 (5–26) | 24 (17–26) | < 0.001 | 24 (15–26) | 23 (9–26) | < 0.001 |
| Ventilator-free days | 21 (0–25) | 23 (12–26) | < 0.001 | 24 (6–26) | 22 (0–25) | < 0.001 |
Data expressed as median (quartile 25%–quartile 75%) or number (%), percentages may not total 100 because of rounding
APACHE Acute Physiology and Chronic Health Evaluation [8], ICU intensive care unit, PaO2/FiO2 partial pressure of arterial oxygen/inspired oxygen concentration ratio
*Variables considered in the cluster process. Patients may have received more than one agent
aOpioids aggregate the use of morphine and/or fentanyl