Table 1 Patient characteristics for the resection surgery group, stratified by age. Baseline variables presented for all subjects, after marginal matching and after caliper matching respectively. Subjects with missing data for any of the variables excluded from the matching
Variables | All subjects (n = 3849) |  | Marginal matched groups |  | Caliper matched groups |  |
|---|---|---|---|---|---|---|
|  |  < 70 years (n = 1471) |  ≥ 70 years (n = 2378) |  < 70 years (n = 1471) |  ≥ 70 years (n = 1578) |  < 70 years (n = 1289) |  ≥ 70 years (n = 1289) |
Sex | ||||||
 Women | 673 (45.8) | 1158 (48.7) | 673 (45.8) | 773 (49.0) | 581 (47.0) | 581 (47.0) |
 Men | 798 (54.2) | 1220 (51.3) | 798 (54.2) | 805 (51.0) | 655 (53.0) | 655 (53.0) |
ASA classification | ||||||
 ASA 1–2 | 1176 (79.9) | 1336 (56.2) | 1176 (82.1) | 1256 (79.6) | 1005 (81.3) | 1005 (81.3) |
 ASA 3 | 249 (16.8) | 887 (37.3) | 247 (17.2) | 302 (19.1) | 223 (18.0) | 223 (18.0) |
 ASA 4–5 | 10 (0.7) | 90 (3.8) | 10 (0.7) | 20 (1.3) | 8 (0.6) | 8 (0.6) |
 Missing | 38 | 64 | - | - | - | - |
Surgical prioritization | ||||||
 Elective | 1320 (89.7) | 2081 (87.5) | 1320 (89.8) | 1427 (90.4) | 1125 (91.0) | 1125 (91.0) |
 Urgent | 150 (10.2) | 296 (12.4) | 150 (10.2) | 151 (9.6) | 111 (9.0) | 111 (9.0) |
 Missing | 1 | 1 | - | - | - | - |
Clinical stage (cTNM) | ||||||
 I | 457 (31.1) | 902 (37.9) | 457 (31.1) | 515 (32.6) | 396 (32.0) | 427 (34.5) |
 II | 303 (20.6) | 558 (23.5) | 303 (20.6) | 365 (23.1) | 269 (21.8) | 295 (23.9) |
 III | 531 (36.1) | 718 (30.2) | 531 (36.2) | 537 (34.0) | 465 (37.6) | 408 (33.0) |
 IV | 177 (12.0) | 193 (8.1) | 177 (12.1) | 161 (10.2) | 106 (8.6) | 106 (8.6) |
 Missing | 3 | 7 | - | - | - | - |
Tumour location | ||||||
 Colon | 935 (63.6) | 1797 (75.6) | 935 (63.7) | 1046 (66.3) | 816 (66.0) | 816 (66.0) |
 Rectum | 533 (36.2) | 578 (24.3) | 533 (36.3) | 532 (33.7) | 420 (34.0) | 420 (34.0) |
 Missing | 3 | 3 | - | - |  |  |
Intraoperative bleeding (ml) | ||||||
 0 | 189 (12.8) | 277 (11.6) | 189 (13.4) | 188 (11.9) | 158 (12.8) | 158 (12.8) |
 1–249 | 854 (58.1) | 1377 (57.9) | 854 (60.4) | 955 (60.5) | 780 (63.1) | 780 (63.1) |
 250–499 | 185 (12.6) | 295 (12.4) | 185 (13.1) | 211 (13.4) | 154 (12.5) | 154 (12.5) |
 500–999 | 101 (6.9) | 222 (9.3) | 101 (7.1) | 157 (9.9) | 90 (7.3) | 90 (7.3) |
 > 1000 | 84 (5.7) | 99 (4.2) | 84 (5.9) | 67 (4.2) | 54 (4.4) | 54 (4.4) |
 Missing | 58 | 108 | - | - | - | - |