Urinary excretion of iohexol as a marker of disease activity in patients with inflammatory bowel disease

Background: Increased intestinal permeability of water-soluble contrast medium during an intestinal follow-through is found in patients with active Crohn's disease in the small bowel. Methods: Urinary excretion of the water-soluble X-ray contrast medium iohexol was measured after oral administration in patients with inflammatory bowel disease and in healthy controls. The patients were grouped on the basis of disease activity and location and extent of intestinal involvement. Results: Urinary excretion of iohexol was significantly higher in patients with active disease than in patients with quiescent disease or in healthy controls (P = 0.005), and it correlated positively with activity indices and with the extent of the disease. Conclusion: The intestinal permeability of iohexol is significantly increased in patients with active inflammatory bowel disease in the small bowel and in the colon, whereas the permeability of patients with inactive disease is similar to that in healthy controls. We suggest that urinary excretion of iohexol can be used as a marker of disease activity in patients with inflammatory bowel disease.