TABLE 1.
Patient and Procedure Characteristics and Outcomes for Patients in Training, Internal Validation, and External Validation Cohorts.
| Training | Internal Validation | External Validation | |
|---|---|---|---|
| (n=4574) | (n=1850) | (n=15360) | |
| Patient Characteristics | |||
| Age (Mean Years, SD) | 53 (17) | 53 (17) | 53 (18) |
| Sex (male, %) | 2248 (49%) | 923 (50%) | 7536 (49%) |
| Race (%) | |||
| White | 4181 (91%) | 1679 (91%) | 14143 (92%) |
| Black or African American | 48 (1%) | 23 (1%) | 126 (1%) |
| Asian | 69 (2%) | 31 (2%) | 191 (1%) |
| Native Hawaiian or Other Pacific Islander | 30 (1%) | 12 (1%) | 147 (1%) |
| American Indian or Alaska Native | 64 (1%) | 28 (2%) | 59 (0%) |
| Hispanic Ethnicity (%) | 455 (10%) | 173 (9%) | 1382 (9%) |
| BMI (Mean, SD) | 29 (7.3) | 29 (6.7) | 29 (7.1) |
| Independent Functional Health Status (%) | 4518 (99%) | 1832 (99%) | 14986 (98%)* |
| Congestive Heart Failure (%) | 21 (0%) | 4 (0%) | 123 (1%) |
| Hypertension (%) | 1533 (34%) | 597 (32%) | 5421 (35%) |
| COPD (%) | 114 (2%) | 44 (2%) | 410 (3%) |
| Current Smoker (%) | 660 (14%) | 237 (13%) | 2236 (15%) |
| Dialysis (%) | 93 (2%) | 26 (1%) | 280 (2%) |
| Diabetes Mellitus (%) | 630 (14%) | 253 (14%) | 2123 (14%) |
| Steroid Use (%) | 284 (6%) | 139 (8%) | 639 (4%)* |
| Weight Loss (%) | 122 (3%) | 31 (2%) | 371 (2%) |
| Open Wound (%) | 262 (6%) | 101 (5%) | 506 (3%)* |
| Procedure Characteristics | |||
| Procedure Type (%) | |||
| Appendectomy | 536 (12%) | 314 (17%)* | 2583 (17%)* |
| Breast | 518 (11%) | 182 (10%) | 1366 (9%)* |
| Colon/Rectal | 826 (18%) | 394 (21%) | 2533 (16%) |
| Esophagus | 184 (4%) | 66 (4%) | 390 (3%)* |
| General Abdominal | 138 (3%) | 30 (2%) | 516 (3%) |
| Hepatobiliary | 448 (10%) | 184 (10%) | 1545 (10%) |
| Hernia | 806 (18%) | 327 (18%) | 3184 (21%) |
| Skin/Subcutaneous | 413 (9%) | 135 (7%) | 987 (6%)* |
| Stomach | 204 (4%) | 31 (2%)* | 205 (1%)* |
| Vascular | 499 (11%) | 186 (10%) | 2037 (13%)* |
| Outpatient Procedure (%) | 2378 (52%) | 993 (54%) | 7578 (49%) |
| Emergent Procedure (%) | 188 (4%) | 45 (2%) | 3224 (21%)* |
| Wound Classification (%) | |||
| Clean | 2349 (51%) | 873 (47%) | 7874 (51%) |
| Clean/Contaminated | 1143 (25%) | 425 (23%) | 3861 (25%) |
| Contaminated | 676 (15%) | 376 (20%)* | 2402 (16%) |
| Dirty/Infected | 406 (9%) | 176 (10%) | 1223 (8%) |
| Operative Duration (minutes, SD) | 120 (100) | 120 (110) | 99 (94)* |
| Hospital Length of Stay (days, SD) | 3.4 (9.5) | 3.1 (5.6) | 3.2 (6.2) |
| Outcomes | |||
| Superficial SSI (%) | 97 (2%) | 24 (1%) | 389 (3%) |
| Deep SSI (%) | 14 (0%) | 4 (0%) | 94 (1%) |
| Organ/Space SSI (%) | 155 (3%) | 47 (3%) | 252 (2%)* |
| SSI Present at the Time of Surgery (%) | 40 (1%) | 19 (1%) | 66 (0%) |
| Any SSI | 255 (6%) | 72 (4%) | 721 (5%) |
*
p<0.001 compared to Training Cohort; SD: Standard Deviation; BMI: Body Mass Index; COPD: Chronic Obstructive Pulmonary Disease