Pancreatic insufficiency (PI) may be an extraintestinal manifestation of inflammatory bowel diseases (IBD). We report the results of a cross-sectional study that was carried out to investigate both the prevalence of PI in IBD patients and its clinical course over a 6-month follow-up period. In total, 100 Crohn's disease (CD) patients, 100 ulcerative colitis (UC) patients, and 100 controls were screened for PI by the fecal elastase-1 (FE-1) test. The decision limits employed were: < or =200 microg/g stool for PI and < or =100 microg/g for severe PI. Patients with abnormal FE-1 values were re-tested after 6 months. Odds ratios (OR) for PI were estimated by unconditional logistic regression analysis. PI was found in 22 UC and 14 CD patients. The OR for the FE-1 test < or =200 microg/g was 10.5 [95% confidence interval (CI): 2.5-44.8] for IBD patients compared to the controls. The risk of PI was related to three or more bowel movements per day (OR = 25.0), the passage of loose stools (OR = 7.7), and previous surgery (OR = 3.7). At the 6-month follow-up, FE-1 values became normal in 24 patients and showed persistently low concentrations in 12. These patients had a larger number of bowel movements per day (OR = 5.4), previous surgery (OR = 5.7), and a longer duration of the disease (OR = 4.2). PI is frequently found in IBD patients, particularly in those with loose stools, a larger number of bowel movements/day and previous surgery. PI is reversible in most patients, and persistent PI is not associated with clinically active disease.