Assessment of orocaecal transit time in different localization of Crohn's disease and its possible influence on clinical response to therapy.

BACKGROUND: A study on orocaecal transit time (OCTT) in patients with different localizations of Crohn's disease (CD) is not available. Because slow-release drug formulations are increasingly available for the treatment, there is a concrete risk that delayed OCTT may impair the efficacy of these formulations.

AIMS: We investigated OCTT before and after therapy using lactulose H2-breath test and we studied whether OCTT can influence the clinical response to therapy with slow-release mesalazine formulations in adult CD patients.(2)

PATIENTS AND METHODS: We studied 45 adult patients with non-obstructive CD and Crohn's Disease Activity Index (CDAI) <200 (29 men, 16 women; mean age 42 years, range 22-73 years). Twenty patients had ileocolonic, 16 colonic and 9 ileal localization of CD. The control group consisted of 20 healthy subjects (13 men, seven women; mean age 53 years, range 22-71 years). After OCTT assessment, 29 patients were treated with time-dependent mesalazine 3.6 g/day, while 16 patients were treated with pH-dependent mesalazine 3.6 g/day. If bacterial overgrowth was detected, the patients were also treated with rifaximin 800 mg/day for 7 days.

RESULTS: OCTT was delayed (120 min, range 115-210 min) in 30 of the 45 CD patients (67%). Four patients (9%) showed bacterial overgrowth, while OCTT was regular (82.5 min, range 75-90 min) in 11 patients (24%). In the control group, the mean OCTT was 88.2 min (range 75-135 min); (P<0.01). OCTT was more prolonged in ileal localization (182.2 min, range 150-210 min), rather than in patients with ileocolonic (122 min, range 75-180 min) or colonic (106 min, range 75-150 min) localization of CD; (P<0.01). Thirty-nine patients showed normal OCTT after starting therapy (83 min, range 75-105 min), while OCTT remained slightly delayed in the remaining patients (110 min, range 105-115 min); (P<0.01). CDAI was <100 (mean value 83) in all patients with reduction of OCTT to normal value 4 months after starting therapy, while it was >140 (mean value 143) in patients with a slight reduction but not normalization of OCTT respectively (five patients with ileal and one with ileocolonic localization of CD) with a statistically significant correlation between OCTT and CDAI (P<0.01).

CONCLUSIONS: This study shows clearly for the first time that OCTT is not only delayed in patients with active CD, but also that it is prolonged in ileal and ileocolonic rather than colonic localization of CD. Moreover we obtained these results using a simple, sensitive, non-invasive and repeatable method, namely, a lactulose hydrogen breath test.