EPIDEMIOLOGIC ASPECTS OF INFLAMMATORY BOWEL-DISEASE IN A NORTH ITALIAN POPULATION - A 4-YEAR PROSPECTIVE-STUDY

Objective: To determine the incidence and clinical characteristics at presentation of inflammatory bowel disease (IBD) in a defined area of north Italy. Design: A 4-year prospective population-based epidemiolog ical study. Setting: An area in Lombardia defined by the National Heal th Service scheme with about 294 000 inhabitants, two referral hospita ls and 259 general practitioners (GPs). Patients: Subjects presenting to a GP with symptoms compatible with IBD underwent a diagnostic work- up at one of the referral hospitals. Those with ulcerative colitis (UC ), Crohn's disease (CD) or indeterminate colitis diagnosed according t o a defined protocol were included, as were residents of the area with IBD diagnosed elsewhere. Rigid case ascertainment methods were used. Patients were followed for one year; 125 patients were identified. Res ults: The patient ascertainment rate was constant over the 4 years; UC was diagnosed in 82 patients, CD in 40, and indeterminate colitis in three. The mean annual incidence of IBD for the whole period was 10.6/ 10(5) inhabitants (95% confidence limits, 7.2-15.1), 7.0/10(5) for UC (4.3-10.7) and 3.4/10(5) (1.6-6.3) for CD. The mean interval between o nset of symptoms and diagnosis was under 6 months. The clinical charac teristics of our patients were similar to those of north European and American series. Conclusion: The incidence of IBD was higher than prev iously observed in Italy but was still lower than in some north Europe an countries and in the USA. Our data could be used as a basis for fut ure longitudinal studies and in international comparative investigatio ns.