Risk factors for colectomy within 10 years*
| Univariate analysis | Multivariate analysis | |||
| HR (95% CI) | P value | HR (95% CI) | P value | |
| Sex (male) | 0.69 (0.39 to 1.23) | 0.21 | 0.67 (0.37 to 1.22) | 0.19 |
| Age at baseline | ||||
| Paediatric (<18 years) | 1.24 (0.59 to 2.59) | 0.57 | 1.11 (0.51 to 2.40) | 0.79 |
| Adult (19–49 years) | Reference | Reference | ||
| Elderly (>50 years) | 0.70 (0.27 to 1.78) | 0.45 | 0.64 (0.24 to 1.67) | 0.79 |
| Disease extent | ||||
| E1, proctitis | 0.71 (0.09 to 5.42) | 0.74 | 0.60 (0.07 to 4.50) | 0.60 |
| E2, left-sided colitis | Reference | Reference | ||
| E3, extensive colitis | 1.87 (0.98 to 3.55) | 0.06 | 1.70 (0.85 to 3.37) | 0.13 |
| Previous medical therapy | ||||
| None | 2.17 (0.20 to 24.21) | 0.53 | 0.62 (0.05 to 7.16) | 0.70 |
| 5-Aminosalicylates | Reference | Reference | ||
| Corticosteroids | 1.34 (0.18 to 9.79) | 0.77 | 1.29 (0.17 to 10.14) | 0.81 |
| Anti-TNF agents | 2.11 (0.83 to 5.36) | 0.12 | 1.73 (0.61 to 4.88) | 0.30 |
| Year of thiopurine initiation† | 0.89 (0.70 to 1.13) | 0.32 | 0.82 (0.63 to 1.07) | 0.14 |
| Thiopurine tolerance‡ | 0.55 (0.31 to 0.98) | 0.04 | 0.39 (0.21 to 0.73) | <0.01 |
| Admitted to hospital at diagnosis | 1.77 (0.95 to 3.32) | 0.07 | 1.55 (0.78 to 3.09) | 0.21 |
*11 patients (thiopurine tolerant, n=6; intolerant, n=5) were colectomised before or within 3 months of initiation of thiopurines and were excluded.
†The time of thiopurine initiation was categorised in 5-year intervals: 1981–1985; 1986–1990; 1991–1995; 1996–2000; 2001–2005; 2006–2010; 2011–2015.
‡The corresponding HR adjusted for age2 as a continuous variable was 0.51 (95% CI 0.28 to 0.92); P=0.02.
Anti-TNF, anti-tumour necrosis factor.