Clinical outcome of Crohn's disease according to the Vienna classification: disease location is a useful predictor of disease course.

OBJECTIVES: Crohn's disease (CD) is a complex genetic disease with multiple clinical patterns. Clinical classifications may help to identify subgroups of patients that have a distinct pattern of disease, and they are also a prerequisite for the conduction of genetic and therapeutic studies. The aim of this study was to determine the usefulness of the Vienna classification in patient care and clinical studies.
METHODS: The clinical data of patients were carefully reviewed retrospectively. The behaviour and location of the disease were determined according to the Vienna classification and additional clinical characteristics including surgical data, vitamin B12 status and medication were also assessed.
RESULTS: Data according to the Vienna classification of 292 CD cases were available. The mean age at diagnosis was 31.4 years. The operation rate was higher in patients with ileocolonic localization (P<0.05) and stricturing and penetrating disease behaviour (P<0.001). The incidence of vitamin B12 deficiency was 41.9% in cases with ileal involvement and 20.7% in cases with disease confined to the colon. In 187 cases (64.0%) an operation was performed because of CD-related complications, in a majority (126, 67.4%) this took place within 5 years after diagnosis. Intolerance of azathioprine occurred in 36 cases (22.0%).
CONCLUSIONS: Ileocolonic disease localization is associated with a complicated course of disease. Vitamin B12 deficiency occurs frequently, also in patients with disease apparently confined to the colon. We propose that location parameters can be used for the prediction of disease course in clinical settings and in interventional studies.