Clinical course in Crohn's disease: results of a five-year population-based follow-up study (the IBSEN study)

There are few population-based, prospective studies on the clinical course in patients with Crohn's disease (CD).

To extend the observation period in a population-based prospective study (the IBSEN study) to find out more about the initial 5-year clinical course in CD patients and to relate the findings to the Vienna classification.

All patients diagnosed with inflammatory bowel disease (IBD) in southeastern Norway in the 4 years 1990-1993 were followed prospectively. The patients were invited to a systematic follow-up visit at their local hospital 1 and 5 years after inclusion in the study. The visits included a structured interview, a clinical examination and colonoscopy.

Out of 843 patients initially diagnosed with IBD, 200 patients with definite CD were alive and had sufficient data for analysis 5 years after diagnosis. Changes in disease localization and behaviour in relation to the Vienna classification were observed in 27 (13.5%) and 35 patients (17.5%), respectively. During the observation period, 56 patients (28%) underwent surgery with intestinal resection, and half of these had disease localized in the terminal ileum. At the time of the 5-year visit, oral sulfasalazin and 5-aminosalicylic acid (5-ASA) were the most frequently used medications (by 54% of the patients), while oral glucocorticosteroids and azathioprine were being used by 25% and 13%, respectively. Seventy-two percent of the patients had taken oral glucocorticosteroids at some time in the course of the 5-year period. The majority of the patients had intestinal symptoms at 5 years, but only 16% had symptoms that interfered with everyday activities. Fourteen percent of the patients had had a relapse-free 5-year course; however, relapse was not related to the initial Vienna classification. When the patients described the clinical course, 44% reported an improvement in symptoms during the follow-up period.

The 5-year clinical course in an unselected cohort of CD patients was mostly mild. The frequency of surgery was lower than that observed in other studies and only a minority of the patients had symptoms that interfered with everyday activities 5 years after the initial diagnosis. The Vienna classification predicted the risk of surgery, but did not predict symptoms at 5 years, relapses during the observation period or the course of disease as described by the patients.