| Total n = 11432 | Ulcerative Colitis (UC) n = 6412 | Crohn’s Disease (CD) n = 4546 |
| Type of IBD (%) * | 56 | 40 |
| Extent of disease | ||
| UC: Extensive | 34 | |
| UC: Left sided | 22 | |
| UC: Distal | 44 | |
| CD: Colonic | 38 | |
| CD: Terminal ileal | 24 | |
| CD: Ileo-colonic | 22 | |
| Gender ratio M:F | 1.08:1 | 0.72:1 |
| Age at diagnosis (mean, years) | 39 | 30 |
| Operated (%) | 16 | 47 (61% once, 20% |
| (41% with pouch) | twice and 19% ⩾×3) | |
| Thiopurine use (%) (range) | 16 (7.7–17.5) | 27 (25.5–27.7) |
| Monoclonal use (%) | 0.1 | 2.8 |
| Mortality (%) | 0.4 | 1.2 |
*4% of patients had indeterminate colitis.