Table 1.
Study demographics for both internal and external data sets.
| Characteristic | Hospital A (internal; N=5775) | Hospital B (external; N=15,434) | P value | ||
| Age at time of surgery (years), mean (SD) | 52.6 (16.6) | 53.4 (18.1) | .01 | ||
| Gender, male, n (%) | 2765 (47.9) | 7576 (49.1) | .12 | ||
| Race, n (%) | |||||
|
|
American Indian or Alaska Native | 86 (1.5) | 59 (0.4) | <.001 | |
|
|
Asian | 81 (1.4) | 192 (1.2) | .40 | |
|
|
Black or African American | 65 (1.1) | 127 (0.8) | .05 | |
|
|
Native Hawaiian or Pacific Islander | 34 (0.6) | 147 (1) | .05 | |
|
|
White | 5275 (91.3) | 14,216 (92.1) | .07 | |
|
|
Unknown or not reported | 234 (4.1) | 693 (4.5) | .18 | |
| Ethnicity, Hispanic, n (%) | 575 (10) | 1384 (9) | .03 | ||
| Procedure Current Procedural Terminology code, n (%) | |||||
|
|
0-29999 (skin/soft tissue) | 968 (16.8) | 2020 (13.1) | <.001 | |
|
|
30000-39999 (cardiovascular) | 594 (10.3) | 2222 (14.4) | <.001 | |
|
|
40000-49999 (gastrointestinal) | 4172 (72.2) | 10,796 (69.9) | .001 | |
|
|
50000-59999 (genitourinary) | 27 (0.5) | 99 (0.6) | .17 | |
|
|
60000-69999 (nervous system) | 14 (0.2) | 297 (1.9) | <.001 | |
| Inpatient or outpatient status, inpatient, n (%) | 2831 (49) | 7837 (50.8) | .02 | ||
| Comorbidities, n (%) | |||||
|
|
Diabetes mellitus | 822 (14.2) | 2144 (13.9) | .54 | |
|
|
Current smoker within 1 year | 799 (13.8) | 2248 (14.6) | .18 | |
|
|
Dyspnea | 498 (8.6) | 373 (2.4) | <.001 | |
|
|
Functional heath status | 71 (1.2) | 376 (2.4) | <.001 | |
|
|
Being ventilator-dependent | 20 (0.3) | 149 (1) | <.001 | |
|
|
History of severe chronic obstructive pulmonary disease | 128 (2.2) | 417 (2.7) | .05 | |
|
|
Ascites within 30 days prior to surgery | 8 (0.1) | 114 (0.7) | <.001 | |
|
|
Congestive heart failure within 30 days prior to surgery | 24 (0.4) | 123 (0.8) | .004 | |
|
|
Hypertension requiring medication | 1940 (33.6) | 5455 (35.3) | .02 | |
|
|
Acute renal failure | 9 (0.2) | 53 (0.3) | .03 | |
|
|
Currently requiring or on dialysis | 100 (1.7) | 283 (1.8) | .66 | |
|
|
Disseminated cancer | 187 (3.2) | 246 (1.6) | <.001 | |
|
|
Open wound with or without infection | 287 (5) | 512 (3.3) | <.001 | |
|
|
Steroid or immunosuppressant use for chronic condition | 351 (6.1) | 644 (4.2) | <.001 | |
|
|
>10% loss of body weight in the 6 months prior to surgery | 145 (2.5) | 372 (2.4) | .71 | |
|
|
Bleeding disorder | 151 (2.6) | 1013 (6.6) | <.001 | |