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.

Treggiari et al. Critical Care 2008 12:R29   doi:10.1186/cc6807