Patient demographic characteristics and comorbidities, and hospital characteristics
| Non-obese | Obese | P value† | |
| n=16 457 | n=1451 | ||
| Demographics, (%) | |||
| Age (years) | |||
| <65 | 9544 (58.03) | 958 (65.94) | <0.0001* |
| ≥65 | 6913 (41.97) | 493 (34.06) | |
| Sex, (%) | |||
| Male | 8729 (53.09) | 698 (48.17) | 0.0003* |
| Female | 7717 (46.91) | 753 (51.83) | |
| Race/ethnicity, (%) | |||
| White | 10 313 (73.05) | 947 (74.75) | <0.0001* |
| Black | 1270 (8.95) | 148 (11.63) | |
| Hispanic | 1138 (8.09) | 103 (8.1) | |
| Other | 1403 (9.92) | 68 (5.51) | |
| Household income, (%)‡ | |||
| Q1 | 3491 (21.7) | 350 (24.69) | 0.001* |
| Q2 | 3879 (24.11) | 379 (26.98) | |
| Q3 | 4101 (25.62) | 335 (23.76) | |
| Q4 | 4535 (28.57) | 345 (24.58) | |
| Insurance status, (%) | |||
| Medicare/medicaid | 7952 (48.33) | 659 (45.59) | 0.08 |
| Private including HMO | 7582 (46.18) | 714 (49.48) | |
| Self-pay/no charge/other | 901 (5.49) | 72 (4.94) | |
| Indication, (%) | |||
| Primary hepatic or biliary malignancy | 5278 (32.08) | 501 (34.55) | 0.05 |
| Other malignancy liver metastasis | 11 179 (67.92) | 950 (65.45) | |
| Admission type, (%) | |||
| Elective | 14 479 (88.17) | 1333 (91.87) | <0.0001* |
| Emergency | 1965 (11.83) | 118 (8.13) | |
| Liver cirrhosis/steatosis/fibrosis, (%) | |||
| Not stated | 14 874 (90.32) | 1231 (84.78) | <0.0001* |
| Steatosis/fibrosis | 432 (2.65) | 121 (8.39) | |
| Cirrhosis | 1151 (7.03) | 99 (6.83) | |
| Surgical extent, (%) | |||
| Lobectomy | 4907 (29.79) | 387 (26.59) | 0.02* |
| Partial hepatectomy | 11 550 (70.21) | 1064 (73.41) | |
| Surgical approach, (%) | |||
| Open | 15 610 (94.84) | 1367 (94.15) | 0.26 |
| Laparoscopic | 847 (5.16) | 84 (5.85) | |
| Comorbidities, (%) | |||
| Alcohol abuse | 459 (2.78) | 45 (3.08) | 0.48 |
| Anaemia | 2411 (14.57) | 248 (16.99) | 0.02* |
| Congestive heart failure | 428 (2.59) | 67 (4.57) | <0.0001* |
| Chronic pulmonary disease | 1711 (10.35) | 234 (16.02) | <0.0001* |
| Coagulopathy | 1354 (8.22) | 129 (8.88) | 0.38 |
| Diabetes, uncomplicated | 2549 (15.43) | 475 (32.66) | <0.0001* |
| Diabetes, complicated | 216 (1.31) | 55 (3.86) | <0.0001* |
| Hypertension | 7383 (44.79) | 950 (65.33) | <0.0001* |
| Fluid/electrolyte disorders | 3606 (21.82) | 357 (24.43) | 0.02* |
| Peripheral vascular disorders | 352 (2.14) | 37 (2.55) | 0.29 |
| Renal failure | 516 (3.13) | 77 (5.24) | <0.0001* |
| Atrial fibrillation | 1155 (7.02) | 118 (8.15) | 0.09 |
| Hospital bed size, (%) | |||
| Small | 1235 (7.37) | 83 (5.72) | 0.07 |
| Medium | 2123 (13.11) | 217 (15.04) | |
| Large | 12 984 (79.52) | 1146 (79.24) | |
| Location/teaching status of hospital | |||
| Rural | 302 (1.78) | 22 (1.48) | 0.70 |
| Urban non-teaching | 1881 (11.3) | 168 (11.39) | |
| Urban teaching | 14 159 (86.92%) | 1256 (87.14%) | |
| Region of hospital | |||
| Northeast | 4049 (25.24) | 300 (21.27) | 0.002* |
| Midwest | 3620 (22) | 365 (25.06) | |
| South | 5473 (32.78) | 545 (37.19) | |
| West | 3315 (19.98) | 241 (16.48) |
Data are presented as unweighted counts (weighted proportion).
*Significant difference between groups, p<0.05.
†X2 test.
‡Household income was extracted and grouped into quartiles (Q1, 0–25th percentile; Q2, 26–50th percentile; Q3, 51st–75th percentile; Q4, 76–100th percentile) based on median total family income within the zip code of the patient’s primary residence.
HMO, Human Maintenance Organization.