Table 1.
Baseline characteristics at intensive care unit admission stratified by study period
| Clinical characteristic | Period I (n = 2,366) 1 Mar 01 to 28 Feb 02 |
Period II (n = 3,322) 1 Mar 02 to 30 Jun 03 |
Period III (n = 4,786) 1 Jul 03 to 28 Feb 05 |
| Age in years, mean ± SD | 51.1 ± 18.5 | 51.6 ± 19.1 | 51.6 ± 19.0 |
| Male gender, n (%) | 1,467 (62.0) | 2,071 (62.4) | 3,044 (63.9) |
| Race or ethnic group, n (%)a | |||
| Native American | 70 (2.96) | 62 (1.87) | 105 (2.20) |
| Asian | 142 (6.00) | 220 (6.63) | 294 (6.17) |
| African-American | 224 (9.47) | 291 (8.77) | 369 (7.74) |
| Caucasian | 1,651 (69.78) | 2,310 (69.60) | 3,422 (71.77) |
| Hispanic | 91 (3.85) | 156 (4.70) | 228 (4.78) |
| Unknown | 188 (7.95) | 283 (8.52) | 350 (7.34) |
| History of diabetes, n (%) | |||
| Type I | 64 (2.7) | 68 (2.1) | 77 (1.6) |
| Type II | 211 (8.92) | 367 (11.1) | 574 (12.0) |
| History of chronic disease, n (%)b | 74 (3.2) | 95 (2.9) | 137 (2.9) |
| SAPS II, mean ± SDc | 39.1 ± 18.1 | 39.3 ± 18.9 | 37.2 ± 18.4 |
| APS III, mean ± SDd | 53.1 ± 21.8 | 53.1 ± 23.3 | 50.5 ± 23.3 |
| Trauma patients, n (%) | 857 (36) | 1,203 (36) | 1,920 (40) |
| Injury Severity Score, mean ± SD | 21.2 ± 10.9 | 20.8 ± 11.1 | 20.7 ± 10.6 |
| Type of admission, n (%) | |||
| Surgical admission | 1,440 (60.9) | 2,003 (60.3) | 3,084 (64.7) |
| Medical admission | 926 (39.1) | 1,319 (39.7) | 1,684 (35.3) |
| Admitting service, n (%) | n = 2,366 | n = 3,314 | n = 4,745 |
| Surgical ICU | 759 (32.1) | 1,061 (32.0) | 1,604 (33.8) |
| Medical ICU | 756 (31.9) | 1,025 (30.9) | 1,303 (27.5) |
| Coronary ICU | 170 (7.19) | 270 (8.2) | 350 (7.4) |
| Neurosurgical ICU | 607 (25.7) | 871 (26.3) | 1,335 (28.1) |
| Burn ICU | 74 (3.1) | 87 (2.6) | 153 (3.2) |
| Weight in kilograms, mean ± SD | 83.0 ± 24.9 | 84.6 ± 26.0 | 84.5 ± 25.5 |
| Admission glucose in mg/dL, mean ± SD | 162.5 ± 88.9 | 161.3 ± 82.5 | 152.1 ± 69.1 |
| Mechanical ventilation, n (%) | 1,424 (60.2) | 1,878 (56.5) | 2,578 (54.1) |
aRace or ethnic group was assigned on the basis of hospital record. bChronic disease defined according to Simplified Acute Physiology Score (SAPS) II criteria. cSAPS II can range from 0 to 162, with higher scores indicating a higher risk of death. dAPS is the acute physiology score of the APACHE (Acute Physiology and Chronic Health Evaluation) III score; it can range from 0 to 251, with higher scores indicating a higher risk of death. ICU, intensive care unit; SD, standard deviation.