Table 1.
Characteristics and Unadjusted Outcomes of Patients Stratified According to ICU Acuity
| Variable | Low-Acuity ICUs (n = 224,294) | Medium-Acuity ICUS (n = 237,128) | High-Acuity ICUs (n = 260,372) | Highest Acuity ICUs (n = 336,716) |
|---|---|---|---|---|
| Age, y | 62.8 ± 17.1 | 63.8 ± 16.7 | 63.4 ± 17.0 | 63.5 ± 16.9 |
| Male sex | 120,002 (53.5) | 128,884 (54.4) | 139,807 (53.7) | 180,612 (53.6) |
| Race | ||||
| White | 170,591 (76.1) | 179,034 (75.5) | 202,091 (77.6) | 251,840 (74.8) |
| Black | 24,442 (10.9) | 28,747 (12.1) | 25,948 (10.0) | 40,643 (12.1) |
| Other | 29,261 (13.0) | 29,347 (12.4) | 32,333 (12.4) | 44,233 (13.1) |
| APACHE IVa score | 47.8 ± 21.8 | 52.4 ± 22.7 | 56.1 ± 24.7 | 62.8 ± 27.8 |
| Admission source | ||||
| ED | 121,960 (54.4) | 127,231 (53.7) | 142,233 (54.6) | 183,399 (54.5) |
| Operating room | 34,083 (15.2) | 44,405 (18.7) | 40,496 (15.6) | 43,639 (13.0) |
| Ward transfer | 28,105 (12.5) | 33,127 (14.0) | 40,475 (15.5) | 57,411 (17.1) |
| Direct admission | 21,524 (9.6) | 16,110 (6.8) | 18,818 (7.2) | 26,122 (7.8) |
| Other | 18,622 (8.3) | 16,255 (6.9) | 18,350 (7.0) | 26,145 (7.8) |
| Admitting diagnosis | ||||
| Cardiac | 55,795 (24.9) | 74,383 (31.4) | 68,566 (26.3) | 74,456 (22.1) |
| Diabetic ketoacidosis | 4,126 (1.8) | 4,992 (2.1) | 5,689 (2.2) | 7,969 (2.4) |
| GI bleeding | 9,876 (4.4) | 12,646 (5.3) | 15,349 (5.9) | 23,062 (6.8) |
| Neurologic | 42,292 (18.9) | 24,772 (10.4) | 27,658 (10.6) | 30,777 (9.1) |
| Overdose | 6,025 (2.7) | 6,742 (2.8) | 8,004 (3.1) | 10,280 (3.1) |
| Respiratory | 5,246 (2.3) | 7,282 (3.1) | 7,473 (2.9) | 10,167 (3.0) |
| Sepsis | 34,884 (15.6) | 44,781 (18.9) | 56,180 (21.6) | 95,483 (28.4) |
| Trauma | 16,115 (7.2) | 9,174 (3.9) | 11,833 (4.5) | 12,124 (3.6) |
| Other | 49,935 (22.3) | 52,356 (22.1) | 59,620 (22.9) | 72,398 (21.5) |
| ICU LOS, d | 2.8 ± 3.5 | 2.9 ± 3.7 | 2.9 ± 3.7 | 3.2 ± 4.1 |
| ICU mortality | 8,493 (3.8) | 10,682 (4.5) | 14,287 (5.5) | 25,367 (7.5) |
| Hospital LOS, d | 6.8 ± 6.5 | 7.4 ± 7.0 | 7.7 ± 7.2 | 8.7 ± 8.2 |
| Hospital mortality | 15,640 (7.0) | 18,648 (7.9) | 22,914 (8.8) | 39,397 (11.7) |
Data are presented as mean ± SD or No. (%). APACHE = Acute Physiology and Chronic Health Evaluation; LOS = length of stay.