Incidence, clinical characteristics, long-term course, and comparison of progressive and nonprogressive cases of aphthous-type Crohn's disease: a single-center cohort study

Abstract

Background/aims: In Japan, aphthous-type Crohn's disease (type A CD) is thought to represent an early phase of Crohn's disease (CD), and diagnosis of type A CD is possible in the diagnostic criteria for CD in Japan. However, the details of type A CD are not well understood.

Methods: Subjects comprised 649 CD patients diagnosed between 1985 and 2011. The incidence of type A CD over time was clarified in two periods (1985-2004 and 2005-2011). The course of type A CD was also investigated, and cases that did and did not progress to typical CD were compared.

Results: No significant difference was seen in the incidence of type A CD between the two periods (5.2 vs. 8.5%, p = 0.125). Type A CD patients followed at our hospital progressed to typical CD at a rate of 59.3%. In comparing progressive and nonprogressive cases, the frequency of large, densely distributed aphthous lesions in the small intestine was higher among progressive cases (p = 0.018).

Conclusion: Type A CD is an early phase of CD, and CD diagnostic criteria including early cases are valid in Japan.