Table 1 Demographic, clinical, and surgical characteristics

Subjects

2947

67,158

2864

2864

Age, years (range)

77 (69–84)

70 (57–80)

− 0.561

77 (69–84)

78 (68–84)

− 0.008

Gender, Male

1884 (63.9%)

40067 (59.7%)

0.088

1815 (63.3%)

1795 (62.7%)

0.014

Body mass index (kg/m²)

21.5 (19.1–24.0)

21.0 (18.7–23.6)

− 0.026

21.5 (19.1–24.0)

21.3 (19.0–23.9)

− 0.014

 Diabetes mellitus

767 (26.0%)

9460 (14.1%)

− 0.302

732 (25.6%)

721 (25.2%)

− 0.009

 Myocardial infarction

101 (3.4%)

296 (0.4%)

− 0.218

89 (3.1%)

77 (2.7%)

− 0.025

 Angina pectoris

172 (5.8%)

772 (1.1%)

− 0.257

150 (5.2%)

139 (4.9%)

− 0.018

 Congestive heart failure

336 (11.4%)

1171 (1.7%)

− 0.397

299 (10.4%)

254 (8.9%)

− 0.053

 Hypertension

1764 (59.9%)

21452 (31.9%)

− 0.584

1697 (59.3%)

1681 (58.7%)

− 0.011

 Cerebrovascular disease

572 (19.4%)

2644 (3.9%)

− 0.497

532 (18.6%)

523 (18.3%)

− 0.008

 COPD

189 (6.4%)

2045 (3.0%)

− 0.159

179 (6.3%)

166 (5.8%)

− 0.019

 CKD with hemodialysis

419 (14.2%)

2172 (3.2%)

− 0.397

388 (13.5%)

370 (12.9%)

− 0.019

 Advanced cancer with metastasis

150 (5.1%)

2993 (4.5%)

− 0.030

148 (5.2%)

158 (5.5%)

0.016

 Long-term steroid use

312 (10.6%)

2718 (4.0%)

− 0.253

292 (10.2%)

280 (9.8%)

− 0.014

 PCI

393 (13.3%)

1123 (1.7%)

− 0.454

345 (12.0%)

299 (10.4%)

− 0.051

 Cardiac surgery

307 (10.4%)

853 (1.3%)

− 0.398

267 (9.3%)

224 (7.8%)

− 0.054

 Peripheral vascular surgery

157 (5.3%)

295 (0.4%)

− 0.295

126 (4.4%)

96 (3.4%)

− 0.054

Activities of daily living

0.429

0.005

 Independent

1901 (64.5%)

55728 (83.0%)

1873 (65.4%)

1868 (65.2%)

 Partial dependent

693 (23.5%)

7610 (11.3%)

656 (22.9%)

657 (22.9%)

 Complete dependent

353 (12.0%)

3819 (5.7%)

335 (11.7%)

339 (11.8%)

Smoking history

397 (13.5%)

14288 (21.3%)

0.207

388 (13.5%)

394 (13.8%)

0.006

Drinking history

1083 (36.8%)

27307 (40.7%)

0.080

1046 (36.5%)

1025 (35.8%)

− 0.016

Preoperative state

 Severe Sepsis/ Septic shock

614 (20.8%)

5981 (8.9%)

0.506

579 (20.2%)

558 (19.5%)

0.024

 Coagulopathy

201 (7.2%)

1209 (1.9%)

− 0.258

163 (6.0%)

163 (6.0%)

− 0.002

 Acute kidney injury

324 (11.0%)

2202 (3.3%)

− 0.303

305 (10.6%)

287 (10.0%)

− 0.021

 Mechanical ventilation

241 (8.2%)

1957 (2.9%)

− 0.232

226 (7.9%)

220 (7.7%)

− 0.008

 Performance status

0.717

0.026

  ASA-1E

53 (1.8%)

10540 (15.7%)

53 (1.9%)

60 (2.1%)

  ASA-2E

685 (23.2%)

26256 (39.1%)

681 (23.8%)

702 (24.5%)

  ASA-3E

1506 (51.1%)

22219 (33.1%)

1460 (51.0%)

1437 (50.2%)

  ASA-4E

512 (17.4%)

6035 (9.0%)

491 (17.1%)

488 (17.1%)

  ASA-5E

191 (6.5%)

2102 (3.1%)

179 (6.3%)

175 (6.1%)

Type of surgery

0.300

0.000

 Peritoneal lavage

906 (30.7%)

22468 (33.5%)

890 (31.1%)

890 (31.1%)

 Gastrectomy

17 (0.6%)

583 (0.9%)

14 (0.5%)

14 (0.5%)

 Patch repair of peptic ulcer

161 (5.5%)

7353 (10.9%)

157 (5.5%)

157 (5.5%)

 Other gastric surgery

9 (0.3%)

226 (0.3%)

8 (0.3%)

8 (0.3%)

 Colorectal resection

649 (22.0%)

11150 (16.6%)

636 (22.2%)

636 (22.2%)

 Other colorectal surgery

34 (1.2%)

708 (1.1%)

33 (1.2%)

33 (1.2%)

 Small bowel obstruction surgery

31 (1.1%)

588 (0.9%)

29 (1.0%)

29 (1.0%)

 Other small intestinal surgery

357 (12.1%)

5980 (8.9%)

344 (12.0%)

344 (12.0%)

 Stoma creation

476 (16.2%)

10002 (14.9%)

466 (16.3%)

466 (16.3%)

 Appendectomy

206 (7.0%)

6852 (10.2%)

194 (6.8%)

194 (6.8%)

 Cholecystectomy

92 (3.1%)

1089 (1.6%)

85 (3.0%)

85 (3.0%)

 Common bile duct surgery

9 (0.3%)

159 (0.2%)

8 (0.3%)

8 (0.3%)

Surgical approach

0.193

− 0.037

 Laparotomy

2688 (91.2%)

57074 (85.0%)

2611 (91.2%)

2640 (92.2%)

 Laparoscopy

259 (8.8%)

10084 (15.0%)

253 (8.8%)

224 (7.8%)

Surgery for cancer

258 (8.8%)

6822 (10.2%)

0.048

256 (8.9%)

276 (9.6%)

0.024

Hospital volume (procedure/year)

78 (40–149)

78 (38–148)

0.029

78 (40–149)

82 (40–152)

− 0.011