Table 1. Characteristics of all participants and the subgroup of patients with or without psychiatric comorbidity.
| Characteristics | Overall (n = 2,745) | Any psychiatric comorbidity* | |
|---|---|---|---|
| No (n = 1,405) | Yes (n = 1,340) | ||
| Demographic factors | |||
| Age, mean ± SD, years | 68.3 ± 11.1 | 69.1 ± 10.9 | 67.4 ± 11.2 |
| Gender (% male) | 65.7 | 68.7 | 62.5 |
| Marital status, n (%) | |||
| Single | 315 (11.5) | 155 (11.0) | 160 (11.9) |
| Married | 1579 (57.5) | 825 (58.7) | 754 (56.3) |
| Divorce | 429 (15.6) | 202 (14.4) | 227 (16.9) |
| Widow/widower | 422 (15.4) | 223 (15.9) | 199 (14.9) |
| Education level,n (%) | |||
| ≤ 9 years | 1072 (39.1) | 552 (39.3) | 520 (38.8) |
| 10–12 years | 1085 (39.5) | 555 (39.5) | 530 (39.6) |
| ≥ 12 years | 483 (17.6) | 249 (17.7) | 234 (17.5) |
| Missing | 105 (3.8) | 49 (3.5) | 56 (4.2) |
| History of psychiatric disorder†, n (%) | |||
| No | 2184 (80.0) | 1284 (91.4) | 900 (67.2) |
| Yes | 561 (20.0) | 121 (8.6) | 440 (32.8) |
| Disease-related factors | |||
| Time of follow-up (from operation to death, emigration or the end of study) | |||
| Mean ± SD, months | 26.1 ± 22.3 | 28.1 ± 23.1 | 24.2 ± 21.2 |
| ASA physical status, n (%) | |||
| I–II | 2033 (74.1) | 1062 (75.6) | 971 (72.5) |
| III–IV | 571 (20.8) | 279 (19.9) | 292 (21.8) |
| Missing | 141 (5.14) | 64 (4.5) | 77 (5.7) |
| Cancer type, n(%) | |||
| Gastric cancer | 1637 (59.6) | 877 (62.4) | 760 (56.7) |
| Esophageal cancer | 1108 (40.4) | 528 (37.6) | 580 (43.3) |
| Cancer stage, n(%) | |||
| Stage 0 | 93 (3.39) | 50 (3.56) | 43 (3.21) |
| Stage I | 739 (26.9) | 388 (27.6) | 351 (26.2) |
| Stage II | 569 (20.7) | 288 (20.5) | 281 (21.0) |
| Stage III | 1167 (42.5) | 592 (42.1) | 575 (42.9) |
| Stage IV | 100 (3.64) | 49 (3.49) | 51 (3.81) |
| Missing | 77 (2.81) | 38 (2.7) | 39 (2.9) |
| Charlson comorbidity index, n (%) | |||
| 0–2 | 1619 (59.0) | 818 (58.2) | 801 (59.8) |
| ≥ 3 | 1126 (41.0) | 587 (41.8) | 539 (40.2) |
| Treatment details | |||
| Hospital Volume, n (%) | |||
| Low (< 20 cases/year) | 319 (11.6) | 171 (12.2) | 148 (11.0) |
| Median (20–40 cases/year) | 321 (11.7) | 157 (11.2) | 164 (12.2) |
| High (> 40 cases/year) | 2104 (76.7) | 1077 (76.6) | 1027 (76.7) |
| Missing | 1 (0.1) | 0 (0.0) | 1 (0.1) |
| Preoperative chemotherapy, n (%) | |||
| No | 1722 (62.7) | 922 (65.6) | 800 (59.7) |
| Yes | 794 (28.9) | 376 (26.8) | 418 (31.2) |
| Missing | 229 (8.34) | 107 (7.6) | 122 (9.1) |
| Preoperative radiotherapy, n(%) | |||
| No | 2227 (81.1) | 1171 (83.4) | 1056 (78.8) |
| Yes | 284 (10.4) | 125 (8.90) | 159 (11.9) |
| Missing | 234 (8.52) | 109 (7.8) | 125 (9.3) |
| Operation type,n (%) | |||
| Curative | 2222 (81.0) | 1157 (82.4) | 1065 (79.5) |
| Palliative | 284 (10.4) | 141 (10.0) | 143 (10.7) |
| Missing | 239 (8.71) | 107 (7.62) | 132 (9.85) |
* Perioperative psychiatric morbidity was defined as a clinical diagnosis of psychiatric disorder through hospital visit or prescription of psychiatric medications, from two years before and to two years after surgery.
†History of psychiatric disorders was determined by psychiatric diagnosis or use of psychiatric medications detected more than two years before operation.