Characeristics of patients in the unmatched cohorts for length of hospital stay
| Variable | No. (%) of patients*; length of stay | p value† | ||||
|---|---|---|---|---|---|---|
| 0 d n = 2431 | 1 d n = 27 816 | 2 d n = 51 305 | 3 d n = 49 127 | 4 d n = 10 915 | ||
| Operation length, min, mean ± SD | 82.1 (32.2) | 87.7 (32.0) | 90.6 (36.7) | 92.6 (40.5) | 99.2 (46.1) | < 0.001 |
| Mean age, yr, mean ± SD | 61.5 (10.5) | 62.2 (10.6) | 63.3 (10.9) | 67.0 (11.7) | 67.9 (12.3) | < 0.001 |
| Sex, female | 1107 (45.5) | 12 442 (44.7) | 26 412 (51.5) | 30 117 (61.3) | 6970 (63.9) | < 0.001 |
| BMI, kg/m2, mean ± SD | 29.2 (5.3) | 29.7 (5.7) | 30.3 (6.2) | 30.5 (6.6) | 30.4 (6.9) | < 0.001 |
| Hypertension | 1079 (44.4) | 13 659 (49.1) | 27 245 (53.1) | 29 501 (60.1) | 6580 (60.3) | < 0.001 |
| COPD | 63 (2.6) | 616 (2.2) | 1478 (2.9) | 2290 (4.7) | 705 (6.5) | < 0.001 |
| CHF | 2 (0.1) | 22 (0.1) | 84 (0.2) | 155 (0.3) | 53 (0.5) | < 0.001 |
| Bleeding disorder | 17 (0.7) | 331 (1.2) | 827 (1.6) | 1124 (2.3) | 361 (3.3) | < 0.001 |
| Diabetes | 209 (8.6) | 2505 (9.0) | 5364 (10.5) | 6466 (13.2) | 1588 (14.6) | < 0.001 |
| Steroid use | 59 (2.4) | 772 (2.8) | 1704 (3.3) | 1847 (3.8) | 532 (4.9) | < 0.001 |
| Smoker | 272 (11.2) | 3475 (12.5) | 6975 (13.6) | 6266 (12.8) | 1402 (12.8) | < 0.001 |
| General anesthesia | 739 (30.4) | 11 806 (42.4) | 25 854 (50.4) | 26 672 (54.3) | 5831 (53.4) | < 0.001 |
| ASA class | ||||||
| 1 | 156 (6.4) | 1451 (5.2) | 2212 (4.3) | 1607 (3.3) | 394 (3.6) | < 0.001 |
| 2 | 1637 (67.3) | 17 445 (62.7) | 29 707 (57.9) | 24 614 (50.1) | 4774 (43.7) | |
| 3 | 617 (6.4) | 8701 (31.3) | 18 781 (36.6) | 22 012 (44.8) | 5427 (49.7) | |
| 4 | 21 (0.9) | 219 (0.8) | 605 (1.2) | 894 (1.8) | 320 (2.9) | |
| Dependent functional status | 14 (0.6) | 187 (0.7) | 558 (1.1) | 1136 (2.3) | 337 (3.1) | < 0.001 |
| Preoperative hematocrit, %, mean ± SD | 41.9 (4.0) | 42.0 (3.9) | 41.5 (4.0) | 40.7 (4.1) | 40.1 (4.3) | < 0.001 |