title: Screening for osteoporosis in patients with inflammatory bowel disease by using urinary N-telopeptides.
abstract: BACKGROUND
  Patients with inflammatory bowel disease are at increased risk of osteoporosis.
  
  
  METHODS
  We carried out a prospective study of bone mineral density and biochemical markers of bone metabolism like osteocalcin and urinary N-telopeptides in 72 patients with inflammatory bowel disease and evaluated if one of these markers detects osteoporosis. In addition, bone mineral density and N-telopeptides were analysed retrospectively in a second series of 93 patients with inflammatory bowel disease in order to assess predictive values found in the first patient group in an independent sample.
  
  
  RESULTS
  Multiple linear regression showed that N-telopeptides (P < 0.0001) and total white blood cell count (P = 0.006) correlated negatively with the bone mineral density of the lumbar spine and only N-telopeptides (P = 0.005) correlated negatively with the bone mineral density of the femoral neck. Using receiver operator characteristic curves N-telopeptide concentrations of > 40 (30) nmol N-telopeptides/mmol creatinine were chosen as best cut-off values to exclude osteoporosis at the lumbar spine (femoral neck). Using these cut-off values a negative predictive value of 100% (100%) and a positive predictive value of 37.5% (27.9%) were found in the first group, and a negative predictive value of 95.2% (96%) and a positive predictive value of 15.6% (23.3%) in the second, independent group of patients.
  
  
  CONCLUSIONS
  Our data suggest that N-telopeptide levels could be used as a tool for the screening of osteoporosis and for selecting those inflammatory bowel disease patients where bone mineral density measurement is indicated.
authors.affiliation: Department of Internal Medicine I, University of Regensburg, Germany. nicole.bregenzer@klinik.uni-regensburg.de
authors.forename: Nicole
authors.initials: N
authors.lastname: Bregenzer
authors.forename: Peter
authors.initials: P
authors.lastname: Erban
authors.forename: Helga
authors.initials: H
authors.lastname: Albrich
authors.forename: Gerd
authors.initials: G
authors.lastname: Schmitz
authors.forename: Stefan
authors.initials: S
authors.lastname: Feuerbach
authors.forename: Jürgen
authors.initials: J
authors.lastname: Schölmerich
authors.forename: Tilo
authors.initials: T
authors.lastname: Andus
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000652:urine*; D015519:Bone Density; D005260:Female; D005269:Femur; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000150:complications*; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000175:diagnosis*; D010455:Peptides / Q000652:urine*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve; D012044:Regression Analysis
chemical_list: D015415:Biomarkers; D010455:Peptides