Table 1.
Demographics and baseline characteristics for all individuals
| Variable | Intervention (n = 681) | Control (n = 663) | P |
|---|---|---|---|
| Age (years), mean(s.d.), median (range) | |||
| All individuals | 67.6(16.8), 71 (18–97) | 66.0(17.5), 69 (18–96) | 0.083 |
| Age group (years), mean(s.d.), median (range) | |||
| 18–40 | 30.9(6.6), 31.5 (18–40) (n = 56) | 30.4(6.5), 31 (18–40) (n = 66) | 0.744 |
| 41–60 | 52.3(5.6), 53 (41–60) (n = 149) | 51.2(5.6), 52 (41–60) (n = 152) | 0.095 |
| 61–75 | 69.0(4.3), 69.5 (61–75) (n = 216) | 68.5(4.1), 69 (61–75) (n = 205) | 0.223 |
| ≥76 | 83.1(5.2), 82 (76–97) (n = 260) | 83.0(4.7), 83 (76–96) (n = 240) | 0.792 |
| Sex | 0.755 | ||
| Male | 317 | 302 | |
| Female | 364 | 361 | |
| Co-morbidity | |||
| Chronic obstructive lung disease | 67 (9.8) | 54 (8.1) | 0.323 |
| Ischaemic heart disease | 95 (14.0) | 80 (12.1) | 0.345 |
| Congestive heart failure | 44 (6.5) | 59 (8.9) | 0.115 |
| Diabetes | 84 (12.3) | 76 (11.5) | 0.683 |
| Chronic renal failure | 26 (3.8) | 30 (4.5) | 0.609 |
| Obesity | 99 (14.5) | 82 (12.4) | 0.278 |
| Smoking | 80 (11.7) | 86 (13.0) | 0.549 |
| No co-morbidity | 357 (52.4) | 333 (50.2) | 0.453 |
| ASA classification | |||
| I | 48 (7.0) | 72 (10.9) | – |
| II | 254 (37.3) | 222 (33.5) | – |
| III | 280 (41.1) | 264 (39.8) | – |
| IV | 79 (11.6) | 94 (14.2) | – |
| V | 20 (2.9) | 11 (1.7) | 0.439 |
| Cancer | 199 (29.2) | 204 (30.8) | 0.581 |
| Diagnosis at surgery | |||
| Peritonitis | |||
| No peritonitis | 532 (78.1) | 489 (73.8) | – |
| Purulent | 38 (5.6) | 42 (6.3) | – |
| Faecal | 59 (8.7) | 48 (7.2) | – |
| Other | 52 (7.6) | 84 (12.7) | 0.015 |
| Intestinal ischaemia | 91 (13.4) | 76 (11.5) | 0.331 |
| Bowel obstruction | |||
| No obstruction | 273/677 (40.3) | 277/659 (42.0) | – |
| Small intestine | 304/677 (44.9) | 314/659 (47.6) | – |
| Colon | 100/677 (14.8) | 68/659 (10.3) | 0.049 |
| Trauma | 15 (2.2) | 20/661 (3.0) | 0.439 |
| Bleeding | 33 (4.8) | 41/659 (6.2) | 0.326 |
| Perforation | |||
| No perforation | 469/675 (69.5) | 460 (69.4) | – |
| Colon | 87/675 (12.9) | 57 (8.6) | – |
| Small intestine | 62/675 (9.2) | 72 (10.9) | – |
| Stomach | 37/675 (5.5) | 56 (8.4) | – |
| Anastomosis | 20/675 (3.0) | 18 (2.7) | 0.027 |
Values are n (%) unless otherwise indicated. For comparisons between groups, Fisher’s exact test (lowest one-sided P value multiplied by two) was used for dichotomous variables, the Mantel–Haenszel chi-squared test was used for ordered categorical variables, the chi-squared test was used for non-ordered categorical variables, and Fisher’s non-parametric permutation test was used for continuous variables.