Table 1 Baseline demographic characteristics and comorbid conditions in training and validation cohorts

Male Sex

2980 (45.8)

2404 (45.9)

576 (45.1)

0.572

Race

0.003

White

Black or African American

Asian

American Indian or Alaska Native

Native Hawaiian or Pacific Islander

Unknown or Not Reported

5318 (81.7)

614 (9.4)

75 (1.2)

15 (0.2)

2 (0.0)

486 (7.5)

4266 (81.5)

472 (9.0)

62 (1.2)

13 (0.2)

1 (0.0)

418 (8.0)

1052 (82.3)

142 (11.1)

13 (1.0)

2 (0.2)

1 (0.1)

68 (5.3)

Hispanic Ethnicity

246 (3.8)

207 (4.0)

39 (3.1)

0.128

Non-Elective Surgery

1244 (19.1)

991 (18.9)

253 (19.8)

0.486

Preoperative Use of a Mobility Aid

1082 (16.6)

854 (16.3)

228 (17.8)

0.191

Fall within the last year

557 (8.6)

453 (8.7)

104 (8.1)

0.551

Weight loss

360 (5.5)

285 (5.4)

75 (5.9)

0.555

Dyspnea

0.010

No

With moderate exertion

At rest

6019 (92.5)

460 (7.1)

31 (0.5)

4859 (92.9)

353 (6.7)

20 (0.4)

1160 (90.8)

107 (8.4)

11 (0.9)

History of COPD

473 (7.3)

377 (7.2)

96 (7.5)

0.706

Insulin dependent diabetes

470 (7.2)

376 (7.2)

94 (7.4)

0.835

Current smoking within the last year

665 (10.2)

541 (10.3)

124 (9.7)

0.500

Ventilator use within 48 h prior to surgery

11 (0.2)

10 (0.2)

1 (0.1)

0.703

Ascites

31 (0.5)

25 (0.5)

6 (0.5)

0.969

Hypertension treated with medication

4212 (64.7)

3377 (64.5)

835 (65.3)

0.596

Disseminated cancer

624 (9.6)

506 (9.7)

118 (9.2)

0.633

History of Congestive Heart Failure

54 (0.8)

41 (0.8)

13 (1.0)

0.409

Renal Failure

14 (0.2)

10 (0.2)

4 (0.3)

0.496

Dialysis

31 (0.5)

23 (0.4)

8 (0.6)

0.386

Wound infection

100 (1.5)

80 (1.5)

20 (1.6)

0.925

Steroid use

365 (5.6)

292 (5.6)

73 (5.7)

0.855

History of bleeding disorder

287 (4.4)

229 (4.4)

58 (4.5)

0.801

Transfusion with 1 or more units of pRBCs prior to surgery

141 (2.2)

113 (2.2)

28 (2.2)

0.945

Sepsis

357 (5.5)

282 (5.4)

75 (5.9)

0.5

Wound Classification

< 0.001

Clean or Clean Contaminated

Contaminated

Dirty

5293 (81.3)

640 (9.8)

577 (8.9)

4299 (82.2)

509 (9.7)

424 (8.1)

994 (77.8)

131 (10.3)

153 (12.0)

American Society of Anesthesiologists class

0.004

1 or 2

3

4 or 5

1795 (27.6)

4240 (65.1)

475 (7.3)

1487 (28.4)

3377 (64.5)

368 (7.0)

308 (24.1)

863 (67.5)

107 (8.4)

Age group

< 0.001

65–69

70–74

75–79

80–84

85–89

2054 (31.6)

1864 (28.6)

1307 (20.1)

838 (12.9)

447 (6.9)

1699 (32.5)

1463 (28.0)

1020 (19.5)

699 (13.4)

351 (6.7)

355 (27.8)

401 (31.4)

287 (22.5)

139 (10.9)

96 (7.5)

BMI group

0.899

Normal BMI

Underweight

Overweight

Obese

Morbidly Obese

Extremely Obese

2052 (31.5)

166 (2.5)

2329 (35.8)

1243 (19.1)

476 (7.3)

244 (3.7)

1658 (31.7)

133 (2.5)

1869 (35.7)

986 (18.8)

388 (7.4)

198 (3.8)

394 (30.8)

33 (2.6)

460 (36.0)

257 (20.1)

88 (6.9)

46 (3.6)

Preoperative HCT < 37

2557 (39.3)

2043 (39.0)

514 (40.2)

0.442

Preoperative sodium < 135

433 (6.7)

341 (6.5)

92 (7.2)

0.381

Preoperative BUN > 22

1194 (18.3)

950 (18.2)

244 (19.1)

0.439

Preoperative creatinine > 2

131 (2.0)

107 (2.0)

24 (1.9)

0.703

Preoperative WBC > 11

685 (10.5)

558 (10.7)

127 (9.9)

0.447

Preoperative albumin < 3.4

880 (13.5)

730 (14.0)

150 (11.7)

0.038