title: Natural history and risk factors for adjacent vertebral fractures in the fracture intervention trial.
abstract: METHODS
  Retrospective analysis of prospectively collected follow-up data for 2.9 years.
  
  
  OBJECTIVE
  To determine the natural history of subsequent morphometric fracture rates at adjacent levels (one level above or below a previous known baseline fracture) in a large patient database.
  
  
  BACKGROUND
  The long-term risk and risk factors for adjacent-level vertebral fractures in patients with osteoporosis are unknown.
  
  
  METHODS
  The fracture intervention trial is a large randomized, placebo-controlled trial of alendronate treatment for osteoporosis. Data from both bisphosphonate-treated and bisphosphonate-naive patients (N = 1950, vertebral fracture arm) was analyzed to detect incident morphometric fracture rates.
  
  
  RESULTS
  During a mean follow-up of 2.9 years, 3.4% of patients in the alendronate group and 7.4% in the placebo group experienced adjacent-level vertebral fractures. The annual rate of adjacent-level vertebral fractures was 1.2% in the alendronate group, and 2.5% in the placebo group (overall, 1.8% per year in both groups combined). As expected, the thoracolumbar region (defined as T11, T12, and L1) seemed to be the most prone to new adjacent-level fractures. Among females with baseline prevalent fractures at the thoracolumbar junction, who subsequently experienced at least one new fracture anywhere along the spine (N = 124), 40.3% had a new adjacent-level fracture in this region. Older age at randomization, lower bone mineral density, inactivity, and placebo therapy were significantly associated with the development of adjacent-level fractures in univariate analysis (P ≤ 0.05). Multivariate analysis indicated decreased odds of adjacent-level fractures with bisphosphonate therapy and higher bone mineral density, and increased odds with older age at randomization (P ≤ 0.05).
  
  
  CONCLUSIONS
  New vertebral fractures adjacent to prevalent fractures occurred relatively infrequently in this treatment trial of alendronate in females with osteoporosis, and were more common with older age at randomization, lower bone mineral density and placebo treatment.
authors.affiliation: *Division of Neurosurgery, Department of Neuroscience, Medical University of South Carolina, Charleston, SC †Departments of Medicine and Epidemiology & Biostatistics, University of California, San Francisco, CA; and ‡Division of Biostatistics and Epidemiology, Department of Medicine, Medical University of South Carolina, Charleston, SC.
authors.forename: Bruce
authors.initials: B
authors.lastname: Frankel
authors.forename: Vibhor
authors.initials: V
authors.lastname: Krishna
authors.forename: Alex
authors.initials: A
authors.lastname: Vandergrift
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Bauer
authors.forename: Joyce
authors.initials: J
authors.lastname: Nicholas
mesh_terms: D000368:Aged; D019386:Alendronate / Q000008:administration & dosage / Q000627:therapeutic use*; D015519:Bone Density / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D010024:Osteoporosis / Q000150:complications; D012189:Retrospective Studies; D012307:Risk Factors; D016103:Spinal Fractures / Q000150:complications / Q000188:drug therapy* / Q000209:etiology
chemical_list: D019386:Alendronate