Cumulative incidence and risk factors for hospitalization and surgery in a population-based cohort of ulcerative colitis

Background: We sought to identify clinical and demographic features influencing hospitalization and colectomy in a population-based inception cohort of ulcerative colitis. Methods: Between 1970 and 2004, a total of 369 patients (58.5% males) from Olmsted County, MN, were followed from diagnosis for 5401 personyears. The cumulative probability of hospitalization and colectomy were estimated using the Kaplan-Meier method. Cox proportional hazards regression was used to identify factors associated with hospitalization and colectomy. Results: The cumulative probability of first hospitalization was 29.4% at 5 years (95% confidence interval [CI], 24.5%-34.1%), 38.7% at 10 years (33.1%-43.8%), 49.2% at 20 years (42.7%-55.2%), and 52.3% at 30 years (45.1%-59.7%). The incidence rate of hospitalizations decreased over the last 4 decades, although cumulative probability of first hospitalization increased with successive decades of diagnosis. Early need for corticosteroids (hazard ratio [HR], 1.8; 95% CI, 1.1%-2.7%) and early need for hospitalization (HR, 1.5; 95% CI, 1.02-2.4) were independent predictors of hospitalization after 90 days of illness. The cumulative probability of colectomy from the time of diagnosis was 13.1% at 5 years (95% CI, 9.4%-16.6%), 18.9% at 10 years (95% CI, 14.4%-23.2%), and 25.4% at 20 years (95% CI, 19.8%-30.8%). Male gender (HR, 2.1; 95% CI, 1.3-3.5), diagnosis in the 1990s (HR, 2.0; 95% CI, 1.01-4.0), and diagnosis in 2000 to 2004 (HR, 3.7; 95% CI, 1.7-8.2) were significantly associated with colectomy risk. Conclusions: Colectomy rates were comparable to reports from northern Europe. The numbers of hospitalizations show a decreasing trend. Male gender and being diagnosed in the 2000 to 2004 period predicted colectomy while extensive colitis predicted future hospitalizations.