Stratification of the study sample according to whether the index subjects had appendicitis at the time of appendicectomy
| Appendicitis diagnosis | Cohort | n | Follow up before/after index date (person years) | No of admission before/after index date | Adjusted ratio of UC admission rate (95% CI) |
|---|---|---|---|---|---|
| An adjusted ratio of ulcerative colitis (UC) admission rate below 1.0 suggests a beneficial effect of appendicectomy on the clinical course of UC. | |||||
| 95% CI, 95% confidence interval. | |||||
| Present | Index | 137 | 646/823 | 108/84 | 1.24 (0.71–2.19) |
| Reference | 548 | 2586/3392 | 411/265 | ||
| Absent | Index | 65 | 307/399 | 63/33 | 0.76 (0.33–1.76) |
| Reference | 260 | 1230/1670 | 220/159 | ||
| All | Index | 202 | 953/1221 | 171/117 | 1.05 (0.67–1.67) |
| Reference | 808 | 3815/5061 | 631/424 | ||