title: Multicenter randomized controlled study to assess the effect of prophylactic clipping on post-polypectomy delayed bleeding.
abstract: OBJECTIVE
  Prophylactic clipping has been widely used to prevent post-procedural bleeding in colon polypctomy. However, its efficiency has not been confirmed and there is no consensus on the usefulness of prophylactic clipping. The aim of the present study was to evaluate the preventive effect of prophylactic clipping on post-polypectomy bleeding.
  
  
  METHODS
  A multicenter randomized controlled study was conducted from January 2012 to July 2013 in Japan. Patients who had polyps <2 cm in diameter were divided into a clipping group and a non-clipping group by cluster randomization. After endoscopic polypectomy, patients allocated to the clipping group underwent prophylactic clipping, whereas the procedure was completed without clipping in patients allocated to the non-clipping group. Occurrence of post-polypectomy bleeding was compared between the two groups.
  
  
  RESULTS
  Seven hospitals participated in this study. A total of 3365 polyps in 1499 patients were evaluated. The clipping group consisted of 1636 polyps in 752 patients, and the non-clipping group consisted of 1729 polyps in 747 patients. Post-polypectomy bleeding occurred in 1.10% (18/1636) of the cases in the clipping group, and in 0.87% (15/1729) of those in the non-clipping group. The difference was -0.22% (95% confidence interval [CI]: -0.96, 0.53). Upper limit of the 95% CI was lower than the non-inferiority margin (1.5%), and we could thus prove non-inferiority of non-clipping against clipping.
  
  
  CONCLUSIONS
  Prophylactic clipping is not necessary to prevent post-polypectomy bleeding for polyps <2 cm in diameter.
authors.affiliation: Department of Gastroenterology, Sapporo Medical Center NTT EC, Sapporo, Japan.
authors.forename: Mio
authors.initials: M
authors.lastname: Matsumoto
authors.affiliation: Division of Endoscopy, Hokkaido University Hospital, Sapporo, Japan.
authors.forename: Mototsugu
authors.initials: M
authors.lastname: Kato
authors.affiliation: Department of Biostatistics, School of Public Health, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Oba
authors.affiliation: Department of Gastroenterology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Abiko
authors.affiliation: Department of Gastroenterology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Momoko
authors.initials: M
authors.lastname: Tsuda
authors.affiliation: Department of Gastroenterology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Shuichi
authors.initials: S
authors.lastname: Miyamoto
authors.affiliation: Department of Gastroenterology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Mizushima
authors.affiliation: Department of Gastroenterology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Ono
authors.affiliation: Department of Gastroenterology, lwamizawa Municipal General Hospital, Iwamizawa, Japan.
authors.forename: Saori
authors.initials: S
authors.lastname: Omori
authors.affiliation: Division of Endoscopy, Hokkaido University Hospital, Sapporo, Japan.
authors.forename: Masakazu
authors.initials: M
authors.lastname: Takahashi
authors.affiliation: Division of Endoscopy, Hokkaido University Hospital, Sapporo, Japan.
authors.forename: Shoko
authors.initials: S
authors.lastname: Ono
authors.affiliation: Department of Cancer Preventive Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Mabe
authors.affiliation: Division of Endoscopy, Hokkaido University Hospital, Sapporo, Japan.
authors.forename: Manabu
authors.initials: M
authors.lastname: Nakagawa
authors.affiliation: Division of Endoscopy, Hokkaido University Hospital, Sapporo, Japan.
authors.forename: Soichi
authors.initials: S
authors.lastname: Nakagawa
authors.affiliation: Department of Gastroenterology, Sapporo City General Hospital, Sapporo, Japan.
authors.forename: Takahiko
authors.initials: T
authors.lastname: Kudo
authors.affiliation: Department of Gastroenterology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Shimizu
authors.affiliation: Department of Gastroenterology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Naoya
authors.initials: N
authors.lastname: Sakamoto
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003111:Colonic Polyps / Q000601:surgery*; D003113:Colonoscopy / Q000009:adverse effects*; D005260:Female; D016558:Hemostasis, Endoscopic / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019106:Postoperative Hemorrhage / Q000517:prevention & control*; D013997:Time Factors; D016896:Treatment Outcome
keywords: colon polypectomy; multicenter randomized controlled study; post-polypectomy bleeding; prophylactic clip; risk factor