Clinical course during the first 10 years of ulcerative colitis: results from a population-based inception cohort (IBSEN Study)

Cohort studies of unselected and newly diagnosed patients are essential for a better understanding of the prognosis in ulcerative colitis (UC). The aim of this study was to evaluate the course of UC in a population-based inception cohort during the first 10 years, and to identify prognostic risk factors based on information gathered at diagnosis. MATERIAL AND METHODS: From 1990 to 1994, a population-based cohort of 843 patients with inflammatory bowel disease was enrolled in South-Eastern Norway. The cohort was systematically followed-up at 1, 5 and 10 years after diagnosis.

Of 519 patients with UC, 423 completed the 10-year follow-up, 53 died and 43 were lost to follow-up. The mortality risk was not increased compared with that in the general population. The cumulative colectomy rate after 10 years was 9.8% (95% CI: 7.4-12.4%). Initial presentation with extensive colitis and erythrocyte sedimentation rate (ESR) > or =30 mm/h was associated with an increased hazard ratio (HR) (3.57, 95% CI: 1.60-7.96) and age > or =50 years at diagnosis, with reduced HR (0.28, 95% CI: 0.12-0.65) for subsequent colectomy. Relapsing disease was noted in 83%, but half (48%) of the patients were relapse free during the last 5 years. One-fifth (69/288) of patients with proctitis or left-sided colitis had progressed to extensive colitis.