title: 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: OBJECTIVE
  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).
  
  
  CONCLUSIONS
  Type A CD is an early phase of CD, and CD diagnostic criteria including early cases are valid in Japan.
authors.affiliation: Department of Gastroenterology, Fukuoka University Chikushi Hospital, Chikushino City, Japan.
authors.forename: Kozue
authors.initials: K
authors.lastname: Tsurumi
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Matsui
authors.forename: Fumihito
authors.initials: F
authors.lastname: Hirai
authors.forename: Noritaka
authors.initials: N
authors.lastname: Takatsu
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Yano
authors.forename: Takashi
authors.initials: T
authors.lastname: Hisabe
authors.forename: Yuho
authors.initials: Y
authors.lastname: Sato
authors.forename: Takahiro
authors.initials: T
authors.lastname: Beppu
authors.forename: Shoko
authors.initials: S
authors.lastname: Fujiwara
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ishikawa
authors.forename: Yu
authors.initials: Y
authors.lastname: Matsushima
authors.forename: Yuki
authors.initials: Y
authors.lastname: Okado
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Ono
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Yoshizawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Nagahama
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Takaki
authors.forename: Kenshi
authors.initials: K
authors.lastname: Yao
authors.forename: Akinori
authors.initials: A
authors.lastname: Iwashita
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D015331:Cohort Studies; D003424:Crohn Disease / Q000175:diagnosis* / Q000453:epidemiology*; D018450:Disease Progression; D005260:Female; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008297:Male; D055815:Young Adult