title: Predictors of new fragility fractures after diagnosis of indolent systemic mastocytosis.
abstract: BACKGROUND
  Fragility fractures (FFxs) and osteoporosis occur frequently in patients with indolent systemic mastocytosis (ISM), even before 50 years of age.
  
  
  OBJECTIVE
  We sought to develop a prediction model to identify individual patients with ISM at risk of new FFxs.
  
  
  METHODS
  Data on lifetime fractures and trauma circumstances were collected from vertebral morphometry, patients' records, and questionnaires. Clinical, lifestyle, and bone characteristics were measured. Patients receiving treatment for osteoporosis before ISM diagnosis or with missing bone data were excluded from FFx risk assessment.
  
  
  RESULTS
  In total, 389 lifetime fractures occurred in 127 of the 221 patients with ISM (age, 19-77 years), including 90 patients with 264 FFxs. Median follow-up after diagnosis was 5.4 years (range, 0.4-15.3 years), with 5- and 10-year FFx risks of 23% ± 3% and 31% ± 4%, respectively. Male sex, high levels of bone resorption (serum type I collagen C-telopeptide), low hip bone mineral density, absence of urticaria pigmentosa, and alcohol intake at the time of ISM diagnosis were independent predictors of future FFxs. The MastFx score, a prediction model using these 5 characteristics, showed good accuracy (area under the curve, 0.80) to determine the risk of new FFxs. QFracture, a validated risk scoring tool for persons aged 30 to 99 years, was not useful in patients with ISM.
  
  
  CONCLUSIONS
  The MastFx score distinguishes patients with ISM at high, intermediate, and low risk of new FFxs. The included characteristics sex, serum type I collagen C-telopeptide, hip bone mineral density, urticaria pigmentosa, and alcohol intake are easy to collect in clinical practice. The high occurrence of FFxs in patients with ISM underlines the importance of optimizing bone quality and early start of therapeutic prevention in patients at risk.
authors.affiliation: Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands. Electronic address: e.van.der.veer@umcg.nl.
authors.forename: Eveline
authors.initials: E
authors.lastname: van der Veer
authors.affiliation: Rheumatology and Clinical Immunology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Suzanne
authors.initials: S
authors.lastname: Arends
authors.affiliation: Allergy, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Sjoukje
authors.initials: S
authors.lastname: van der Hoek
authors.affiliation: Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Joris B
authors.initials: JB
authors.lastname: Versluijs
authors.affiliation: Allergy, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Jan G R
authors.initials: JGR
authors.lastname: de Monchy
authors.affiliation: Allergy, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; GRIAC Research Institute, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Joanna N G
authors.initials: JNG
authors.lastname: Oude Elberink
authors.affiliation: Allergy, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Jasper J
authors.initials: JJ
authors.lastname: van Doormaal
mesh_terms: D000328:Adult; D000428:Alcohol Drinking; D015519:Bone Density; D024042:Collagen Type I / Q000097:blood; D005260:Female; D050723:Fractures, Bone / Q000097:blood / Q000453:epidemiology* / Q000503:physiopathology; D006615:Hip / Q000502:physiology; D006801:Humans; D008297:Male; D034721:Mastocytosis, Systemic / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology; D008875:Middle Aged; D008954:Models, Biological; D010455:Peptides / Q000097:blood; D012307:Risk Factors; D012737:Sex Factors; D014582:Urticaria Pigmentosa / Q000453:epidemiology
chemical_list: D024042:Collagen Type I; D010455:Peptides; C052929:collagen type I trimeric cross-linked peptide
keywords: Systemic mastocytosis; alcohol; bone mineral density; bone turnover markers; fracture risk scoring tool; fragility fractures; serum type I collagen C-telopeptide; sex; urticaria pigmentosa