title: A C-terminal crosslinking telopeptide test-based protocol for patients on oral bisphosphonates requiring extraction: a prospective single-center controlled study.
abstract: OBJECTIVE
  Patients undergoing extraction are at risk for bisphosphonate-related osteonecrosis of the jaws (BRONJ). A C-terminal crosslinking telopeptide (CTX) level lower than 150 pg/mL has been suggested as a predictor of BRONJ risk. The authors aimed to increase the precision of estimates of the risk of BRONJ in osteoporosis after extraction and to assess value of CTX testing at extraction time in cases of BRONJ in a large prospective cohort.
  
  
  METHODS
  All patients on oral bisphosphonates for osteoporosis referred for extractions over a period of 6.5 years were included in a standard protocol. Pre-extraction fasted CTX levels were obtained. All patients were followed until healing. If the CTX level was lower than 150 pg/mL, they were offered a drug holiday. If they declined, if the CTX level was above 150 pg/mL at baseline, or after the drug holiday, they had extractions performed under local anesthesia. Age-matched controls not on bisphosphonates were identified.
  
  
  RESULTS
  Nine hundred fifty patients had 2,461 extractions. One hundred eighty-one patients had a CTX level lower than 150 pg/mL. Four patients developed BRONJ; all had a CTX level lower than 150 pg/mL. All were on alendronate. The case-control comparison approached significance (<150 pg/mL; P = .073). Alendronate was associated with a low CTX level (P < .05). A CTX level lower than 150 pg/mL had a sensitivity of 100% and specificity of 81%. Bayesian analysis yielded a population expected risk of BRONJ of 0.29% (95% confidence interval, 0.12-0.52); the expected risk was 0.42% for a CTX level lower than 150 pg/mL and 0.13% for a CTX level higher than 150 pg/mL.
  
  
  CONCLUSIONS
  The risk of BRONJ for patients with osteoporosis on bisphosphonates having extractions is approximately 0.2%. A CTX level lower than 150 pg/mL is sensitive and is associated with an approximately 3-fold greater risk of BRONJ.
authors.affiliation: Honor Student, The University of Adelaide, Adelaide, South Australia, Australia.
authors.forename: April
authors.initials: A
authors.lastname: Hutcheson
authors.affiliation: Consultant, formerly Registrar for Oral and Maxillofacial Surgery, The University of Adelaide, Adelaide, South Australia, Australia.
authors.forename: Andrew
authors.initials: A
authors.lastname: Cheng
authors.affiliation: Registrar for Oral and Maxillofacial Surgery, The University of Adelaide, Adelaide, South Australia, Australia.
authors.forename: Ranjit
authors.initials: R
authors.lastname: Kunchar
authors.affiliation: Medical Oncologist, Adelaide Cancer Centre, The University of Adelaide, Adelaide, South Australia, Australia.
authors.forename: Brian
authors.initials: B
authors.lastname: Stein
authors.affiliation: Director, Oral and Maxillofacial Surgical Unit, The University of Adelaide, Adelaide, South Australia, Australia.
authors.forename: Paul
authors.initials: P
authors.lastname: Sambrook
authors.affiliation: Professor and Emeritus Consultant, The University of Adelaide and Royal Adelaide Hospital, Adelaide, South Australia, Australia. Electronic address: alastair.goss@adelaide.edu.au.
authors.forename: Alastair
authors.initials: A
authors.lastname: Goss
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001499:Bayes Theorem; D024042:Collagen Type I / Q000378:metabolism*; D004164:Diphosphonates / Q000008:administration & dosage / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000188:drug therapy; D010455:Peptides / Q000378:metabolism*; D011446:Prospective Studies; D018570:Risk Assessment; D014081:Tooth Extraction
chemical_list: D024042:Collagen Type I; D004164:Diphosphonates; D010455:Peptides; C052929:collagen type I trimeric cross-linked peptide