title: Comparison of iohexol and lactulose-mannitol tests as markers of disease activity in patients with inflammatory bowel disease.
abstract: Increased intestinal permeability has been proposed as one aetiological factor for inflammatory bowel diseases (IBD). We have previously found that intestinal permeability of a water-soluble contrast medium, iohexol, correlates with disease activity. The objective was to compare the iohexol test with the lactulose-mannitol ratio, which is a more extensively studied permeability marker, in patients with active IBD. Urinary excretion of iohexol was compared to the lactulose-mannitol ratio in 22 patients with an exacerbation of IBD and in 10 healthy controls. Median intestinal absorption of iohexol was 0.64% (range 0.13-3.8%) in the 22 patients and 0.3% (range 0.15-0.54%) in the controls (p = 0.016), whereas the median lactulose-mannitol ratio was 0.037 (range 0.01-0.260) in patients and 0.03 (range 0.004-0.063) in controls (N.S.). Correlation between urinary excretion of iohexol and lactulose-mannitol ratio was positive (R = +0.41, p = 0.018). The urinary excretion of iohexol correlated positively with endoscopic disease activity (R = +0.74, p < 0.001) and the modified Harvey-Bradshaw index (R = +0.44, p = 0.04). The lactulose-mannitol ratio correlated positively with endoscopic disease activity (R = +0.44, p = 0.05), but correlations with clinical index or c-reactive protein were poor. In conclusion, the iohexol test is a superior activity marker compared to the lactulose-mannitol ratio which probably reflects, instead, some pathogenic property of IBD.
authors.affiliation: Fourth Department of Surgery, Helsinki University Hospital, Finland. leena.halme@hus.fi
authors.forename: L
authors.initials: L
authors.lastname: Halme
authors.forename: U
authors.initials: U
authors.lastname: Turunen
authors.forename: J
authors.initials: J
authors.lastname: Tuominen
authors.forename: T
authors.initials: T
authors.lastname: Forsström
authors.forename: U
authors.initials: U
authors.lastname: Turpeinen
mesh_terms: D000328:Adult; D000368:Aged; D003093:Colitis, Ulcerative / Q000503:physiopathology; D003424:Crohn Disease / Q000503:physiopathology; D016099:Endoscopy, Gastrointestinal; D005260:Female; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000503:physiopathology*; D007408:Intestinal Absorption; D007472:Iohexol / Q000378:metabolism; D007792:Lactulose / Q000652:urine; D008297:Male; D008353:Mannitol / Q000652:urine; D008875:Middle Aged; D010539:Permeability; D012996:Solutions
chemical_list: D012996:Solutions; D008353:Mannitol; D007472:Iohexol; D007792:Lactulose