Variable | Without appendicitis (N=3 125 232)* | Appendicitis (N=35 848)* | P value† |
Median follow-up time (years) | 18 (10, 27) | 9 (7, 13) | <0.001 |
Age at the end of follow-up (years) | 38 (30, 47) | 29 (27, 33) | <0.001 |
Sex | <0.001 | ||
Male | 1 607 461 (51%) | 20 298 (57%) | |
Female | 1 517 771 (49%) | 15 550 (43%) | |
Household Crowding Index | 1.00 (0.75, 1.33) | 1.00 (0.67, 1.00) | <0.001 |
Missing | 165 389 | 2752 | |
Socio-Economic Index | <0.001 | ||
Agriculture | 89 106 (2.9%) | 550 (1.5%) | |
Low | 1 060 511 (34%) | 11 183 (31%) | |
Medium | 1 165 328 (37%) | 13 435 (37%) | |
High | 487 285 (16%) | 5792 (16%) | |
Other | 174 320 (5.6%) | 2468 (6.9%) | |
Unknown | 148 682 (4.8%) | 2420 (6.8%) | |
Region | <0.001 | ||
Götaland | 1 425 557 (46%) | 15 697 (44%) | |
Norrland | 417 773 (13%) | 5126 (14%) | |
Svealand | 1 121 744 (36%) | 13 512 (38%) | |
Unknown | 160 158 (5.1%) | 1513 (4.2%) | |
Age of appendicectomy (years) | 29 (24, 36)‡ | 15 (12, 18) | |
Ulcerative colitis | 20 848 (0.7%) | 59 (0.2%) | <0.001 |
Crohn’s disease | 12 003 (0.4%) | 93 (0.3%) | <0.001 |
*Median (IQR); n (%).
†Wilcoxon rank sum test; Pearson’s χ2 test.
‡Individuals who underwent appendicectomy for reasons other than acute appendicitis.