title: Evaluation of postextraction bleeding incidence to compare patients receiving and not receiving warfarin therapy: a cross-sectional, multicentre, observational study.
abstract: OBJECTIVE
  We investigated incidence and risk factors for postextraction bleeding in patients receiving warfarin and those not receiving anticoagulation therapy.
  
  
  METHODS
  Cross-sectional, multicentre, observational study.
  
  
  METHODS
  26 hospitals where an oral surgeon is available.
  
  
  METHODS
  Data on 2817 teeth (from 496 patients receiving warfarin, 2321 patients not receiving warfarin; mean age (SD): 62.2 (17.6)) extracted between 1 November 2008 and 31 March 2010, were collected. Warfarin-receiving patients were eligible when prothrombin time-international normalised ratio (PT-INR) measured within 7 days prior to the extraction was less than 3.0.
  
  
  METHODS
  Simple dental extraction was performed, and incidence of postextraction bleeding and comorbidities were recorded.
  
  
  METHODS
  Postextraction bleeding not controlled by basic haemostasis procedure was clinically significant.
  
  
  RESULTS
  Bleeding events were reported for 35 (7.1%) and 49 (2.1%) teeth, of which 18 (3.6%) and 9 (0.4%) teeth were considered clinically significant, in warfarin and non-warfarin groups, respectively, the difference between which was 3.24% (CI 1.58% to 4.90%). The incidence rates by patients were 2.77% and 0.39%, in warfarin and non-warfarin groups, respectively (incidence difference 2.38%, CI 0.65% to 4/10%). Univariate analyses showed that age (OR 0.197, p=0.001), PT-INR (OR 3.635, p=0.003), mandibular foramen conduction anaesthesia (OR 4.854, p=0.050) and formation of abnormal granulation tissue in extraction socket (OR 2.900, p=0.031) significantly correlate with bleeding incidence. Multivariate analysis revealed that age (OR 0.126, p=0.001), antiplatelet drugs (OR 0.100, p=0.049), PT-INR (OR 7.797, p=0.001) and history of acute inflammation at extraction site (OR 3.722, p=0.037) were significant risk factors for postextraction bleeding.
  
  
  CONCLUSIONS
  Our results suggest that there is slight but significant increase in the incidences of postextraction bleeding in patients receiving warfarin. Although absolute incidence was low in both groups, the bleeding risk is not negligible.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Kanagawa Dental University, Yokosuka, Kanagawa, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Iwabuchi
authors.affiliation: Department of Oral & Maxillofacial Surgery, Dokkyo Medical University School of Medicine, Shimotsuga-gun, Tochigi, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Imai
authors.affiliation: Department of Dentistry and Implant Center, Sanno Hospital, Minato-ku, Tokyo, Japan.
authors.forename: Soichiro
authors.initials: S
authors.lastname: Asanami
authors.affiliation: Nippon Dental University, Chiyoda-ku, Tokyo, Japan.
authors.forename: Masayori
authors.initials: M
authors.lastname: Shirakawa
authors.affiliation: Tokyo Dental College, Chiyoda-ku, Tokyo, Japan.
authors.forename: Gen-yuki
authors.initials: GY
authors.lastname: Yamane
authors.affiliation: Tokyo Women's Medical University, Shinjuku-ku, Tokyo, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Ogiuchi
authors.affiliation: Oral & Dental Center, Aizawa Hospital, Matsumoto, Nagano, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Kurashina
authors.affiliation: Department of Dentistry and Oral Surgery, Ishikawa Prefectural Central Hospital, Kanazawa, Ishikawa, Japan.
authors.forename: Masaru
authors.initials: M
authors.lastname: Miyata
authors.affiliation: Department of Epidemiology, National Institute of Public Health of Japan, Wako, Saitama, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Nakao
authors.affiliation: Department of Epidemiology, National Institute of Public Health of Japan, Wako, Saitama, Japan.
authors.forename: Hirohisa
authors.initials: H
authors.lastname: Imai
mesh_terms: D000367:Age Factors; D000368:Aged; D000758:Anesthesia / Q000009:adverse effects; D000925:Anticoagulants / Q000009:adverse effects* / Q000627:therapeutic use; D001777:Blood Coagulation; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D015994:Incidence; D007249:Inflammation / Q000150:complications; D019934:International Normalized Ratio; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D010975:Platelet Aggregation Inhibitors / Q000009:adverse effects / Q000627:therapeutic use; D019106:Postoperative Hemorrhage / Q000453:epidemiology / Q000209:etiology*; D011517:Prothrombin Time; D013923:Thromboembolism / Q000517:prevention & control; D014070:Tooth; D014081:Tooth Extraction / Q000009:adverse effects*; D020390:Tooth Socket / Q000473:pathology; D014859:Warfarin / Q000009:adverse effects* / Q000627:therapeutic use
chemical_list: D000925:Anticoagulants; D010975:Platelet Aggregation Inhibitors; D014859:Warfarin
keywords: ORAL & MAXILLOFACIAL SURGERY; ORAL MEDICINE