Table 1 Baseline characteristics of the study cohort stratified by time of ICU discharge
Characteristics | Total | Nighttime discharges | Daytime discharges | P value |
|---|---|---|---|---|
n: 19,622 | n = 3,505 (17.9 %) | n = 16,117 (82.1 %) | ||
Male sex, n (%) | 11,357 (57.9) | 1,986 (56.7) | 9,371 (58.1) | 0.11 |
Age (years) (mean [SD]) | 57.5 (18.0) | 57.2 (17.9) | 57.5 (18.0) | 0.30 |
Apache II score (mean [SD]) | 19.4 (7.5) | 20.1 (7.6) | 19.3 (7.4) | <0.001 |
Medical admission, n (%) | 13,018 (66.3) | 2,596 (74.1) | 10,422 (64.7) | <0.001 |
Post-operative, n (%) | 6,604 (33.7) | 909 (25.9) | 5,695 (35.3) | <0.001 |
Comorbid illness, n (%) | ||||
None | 15,180 (77.4) | 2,662 (76.0) | 12,518 (77.7) | 0.027 |
One | 3,927 (20.0) | 730 (20.8) | 3,197 (19.8) | 0.19 |
Two or more | 515 (2.6) | 113 (3.2) | 402 (2.5) | 0.014 |
Comorbid condition, n (%) | ||||
Hepatic failure | 873 (4.5) | 150 (4.3) | 723 (4.5) | 0.59 |
Immunosuppression | 981 (5.0) | 207 (5.9) | 774 (4.8) | 0.007 |
Chronic lung disease | 1,355 (6.9) | 228 (6.5) | 1,127 (7.0) | 0.30 |
Chronic renal failure | 613 (3.1) | 159 (4.5) | 454 (2.8) | <0.001 |
Hematologic cancer | 314 (1.6) | 63 (1.8) | 251 (1.6) | 0.31 |
Metastatic cancer | 465 (2.4) | 83 (2.4) | 382 (2.4) | 0.99 |
Congestive heart failure | 293 (1.5) | 53 (1.5) | 240 (1.5) | 0.92 |
AIDS | 82 (0.4) | 16 (0.5) | 66 (0.4) | 0.69 |
Primary diagnosis, n (%) | ||||
Respiratory | 5,940 (30.3) | 1,099 (31.4) | 4,841 (30.0) | 0.12 |
Gastrointestinal | 3,342 (17.0) | 520 (14.8) | 2,822 (17.5) | <0.001 |
Cardiovascular | 2,822 (14.4) | 448 (12.8) | 2,374 (14.7) | 0.003 |
Sepsis | 1,548 (7.9) | 295 (8.4) | 1,253 (7.8) | 0.20 |
Trauma | 1,699 (8.7) | 312 (8.9) | 1,387 (8.6) | 0.57 |
Metabolic | 1,640 (8.4) | 315 (9.0) | 1,325 (8.2) | 0.14 |
Neurologic | 1,385 (7.1) | 293 (8.4) | 1,092 (6.8) | 0.001 |
Renal | 626 (3.2) | 121 (3.5) | 505 (3.1) | 0.33 |
Other | 620 (3.2) | 102 (2.9) | 518 (3.2) | 0.35 |
Mechanical ventilation, n (%) | 14,349 (73.1) | 2,641 (75.3) | 11,708 (72.6) | 0.001 |
Source of admission, n (%) | ||||
Emergency department | 6,370 (32.5) | 1,275 (36.4) | 5,095 (31.6) | <0.001 |
Operating room - Elective | 3,165 (16.1) | 401 (11.4) | 2,764 (17.1) | <0.001 |
Operating room – Emergency | 3,438 (17.5) | 508 (14.5) | 2,930 (18.2) | <0.001 |
Other hospital | 3,140 (16.0) | 603 (17.2) | 2,537 (15.7) | 0.032 |
Ward | 3,509 (17.9) | 718 (20.5) | 2,791 (17.3) | <0.001 |
Year of admission, n (%) | ||||
2002/2003 | 3852 (19.6) | 577 (14.9) | 3275 (75.1) | <0.01* |
2004/2005 | 4929 (25.1) | 801 (16.2) | 4128 (83.8) | |
2006/2007 | 5400 (27.5) | 1007 (18.6) | 4393 (81.4) | |
2008/2009 | 5441 (27.7) | 1120 (20.6) | 4321 (79.4) | |
ICU LOS, (d) (med [IQR]) | 3 (1–7) | 3 (1–7) | 3 (2–7) | 0.09 |
Source of discharge, n (%) | ||||
Ward | 17,935 (91.4) | 3,199 (91.3) | 14,736 (91.4) | 0.75 |
Acute care | 979 (5.0) | 260 (7.4) | 719 (4.5) | <0.001 |
Home | 585 (3.0) | 31 (0.9) | 554 (3.4) | <0.001 |
Left without authorization | 75 (0.4) | 11 (0.3) | 64 (0.4) | 0.46 |
Chronic care | 48 (0.2) | 4 (0.1) | 44 (0.3) | 0.08 |
Weekend discharges | 4,676 (23.8) | 779 (16.7) | 3,897 (83.3) | 0.014 |
Weekday discharges | 14,946 (76.2) | 2,726 (18.2) | 12,220 (81.8) | 0.014 |