The sugar permeability test reflects disease activity in children and adolescents with inflammatory bowel disease

Objectives: To investigate the relationship of intestinal permeability in children and adolescents with inflammatory bowel disease (IBD) to disease activity, disease extent, and response to therapy. Study design: Patients with new and established diagnoses of IBD (12 Crohn's disease [CD] and 18 ulcerative colitis [UC]) were studied. Intestinal permeability was evaluated by measuring with high-performance liquid chromatography 5-hour urinary excretion ratio of lactulose/L-rhamnose (L/Rh). Results: In 8 of 9 patients with active CD, the L/Rh ratio was higher than the reference range (0.006 to 0.074, n = 36). In inactive CD (n = 3) the L/Rh ratio was within the reference range. In 6 of 7 patients with active extensive UC, the L/Rh ratio was elevated. In inactive extensive UC (n = 6) the normal permeability ratio was shown. In both active CD and active extensive UC, the frequency of elevated intestinal permeability was significantly greater than values in both inactive forms. The permeability ratio was normal in 4 of 5 patients with active left-sided colitis. In 5 of 7 patients (3 CD, 4 UC), repeat permeability values entered the reference range after acute phase therapy. Two patients with persistently elevated intestinal permeability (1 CD, 1 UC) had a disease flare-up within 6 months. Conclusions: Intestinal permeability is a marker of disease activity in CD and extensive UC. Serial permeability test may be useful in monitoring disease activity.