title: The clinical characteristics of patients with free perforation in Korean Crohn's disease: results from the CONNECT study.
abstract: BACKGROUND
  Free perforation is the most severe and debilitating complication associated with Crohn's disease (CD), and it usually requires emergency surgery. The aim of this study was to evaluate the incidence of free perforation among Korean patients with CD.
  
  
  METHODS
  The CrOhn's disease cliNical NEtwork and CohorT (CONNECT) study was conducted nationwide in Korea, and patients who were diagnosed with CD between 1982 and 2008 were included in this retrospective study. We investigated the incidence of free perforation among these patients and their clinical characteristics.
  
  
  RESULTS
  A total of 1346 patients were analyzed and 88 patients (6.5%) were identified with free perforation in CD. The mean age of the free perforation group was 31.8 ± 13.0 years, which was significantly higher than that of the non-perforated group (27.5 ± 12.1 years) (p = 0.004). Free perforation was the presenting sign of CD in 46 patients (52%). Of the 94 perforations that were present in 88 patients, 81 involved the ileum. Multivariate logistic regression analysis determined that free perforation was significantly associated with being aged ≥ 30 years at diagnosis (OR 2.082, p = 0.002) and bowel strictures (OR 1.982, p = 0.004). The mortality rate in the free perforation group was significantly higher (4.5%) than that in the non-perforated group (0.6%) (p < 0.001).
  
  
  CONCLUSIONS
  The incidence of free perforation in Korean patients with CD was 6.5%. Being aged ≥ 30 years at CD diagnosis and bowel strictures were significant risk factors associated with free perforation.
authors.affiliation: Department of Internal Medicine, Seoul Paik Hospital, Inje University College of Medicine, 85 Geo-dong 2 ga, Jung-gu, Seoul, 100-032, South Korea. elimier@hanmail.net.
authors.forename: Young Seok
authors.initials: YS
authors.lastname: Doh
authors.affiliation: Department of Internal Medicine, Seoul Paik Hospital, Inje University College of Medicine, 85 Geo-dong 2 ga, Jung-gu, Seoul, 100-032, South Korea. yousunk69@korea.com.
authors.forename: You Sun
authors.initials: YS
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Seoul Paik Hospital, Inje University College of Medicine, 85 Geo-dong 2 ga, Jung-gu, Seoul, 100-032, South Korea. auuul@hanmail.net.
authors.forename: Song I
authors.initials: SI
authors.lastname: Bae
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, South Korea. jpim0911@snu.ac.kr.
authors.forename: Jong Pil
authors.initials: JP
authors.lastname: Im
authors.affiliation: Department of Internal Medicine, Yonsei University College of Medicine, Seoul, South Korea. GENIUSHEE@yuhs.ac.
authors.forename: Jae Hee
authors.initials: JH
authors.lastname: Cheon
authors.affiliation: Department of Internal Medicine, University of Ulsan College of Medicine, Seoul, South Korea. bdye@amc.seoul.kr.
authors.forename: Byong Duk
authors.initials: BD
authors.lastname: Ye
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, South Korea. giwkim@hanmail.net.
authors.forename: Ji Won
authors.initials: JW
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Eulji University College of Medicine, Seoul, South Korea. pys1109@eulji.ac.kr.
authors.forename: Young Sook
authors.initials: YS
authors.lastname: Park
authors.affiliation: Department of Internal Medicine, Seoul Song Do Colorectal Hospital, Seoul, South Korea. chelsia3@empal.com.
authors.forename: Ji Hyun
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Sungkyunkwan University School of Medicine, Seoul, South Korea. younghokim@skku.edu.
authors.forename: Young-Ho
authors.initials: YH
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, South Korea. jooskim@snu.ac.kr.
authors.forename: Joo Sung
authors.initials: JS
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Hanyang University College of Medicine, Guri, South Korea. hands@hanyang.ac.kr.
authors.forename: Dong Soo
authors.initials: DS
authors.lastname: Han
authors.affiliation: Department of Internal Medicine, Yonsei University College of Medicine, Seoul, South Korea. kimwonho@yuhs.ac.
authors.forename: Won Ho
authors.initials: WH
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D003251:Constriction, Pathologic / Q000453:epidemiology; D003424:Crohn Disease / Q000150:complications* / Q000175:diagnosis / Q000401:mortality; D057210:Delayed Diagnosis; D005260:Female; D006801:Humans; D007077:Ileal Diseases / Q000453:epidemiology* / Q000209:etiology / Q000601:surgery; D015994:Incidence; D007416:Intestinal Perforation / Q000453:epidemiology* / Q000209:etiology / Q000401:mortality / Q000601:surgery; D007422:Intestines / Q000473:pathology; D007579:Jejunal Diseases / Q000453:epidemiology* / Q000209:etiology / Q000601:surgery; D008297:Male; D056910:Republic of Korea / Q000453:epidemiology; D012189:Retrospective Studies; D012307:Risk Factors; D055815:Young Adult