title: Radiographic vertebral fractures develop in patients with ankylosing spondylitis during 4 years of TNF-α blocking therapy.
abstract: OBJECTIVE
  To determine the prevalence and incidence of radiographic vertebral fractures in ankylosing spondylitis (AS) patients treated with TNF-α blocking therapy for 4 years and to explore the relationship with patient characteristics, clinical assessments, radiographic damage, and bone mineral density (BMD).
  
  
  METHODS
  This study included consecutive AS patients with active disease from the Groningen Leeuwarden AS (GLAS) cohort treated with TNF-α blocking therapy for 4 years and with available thoracic and lumbar radiographs at baseline and at 4 years. Vertebral fractures were assessed by two readers (mild: ≥20-<25%, moderate: ≥25-<40%, severe: ≥40% reduction in vertebral height).
  
  
  RESULTS
  In 27 of 105 (26%) AS patients, radiographic vertebral fractures were observed at baseline. These patients were significantly older, had larger occiput-to-wall distance, and more spinal radiographic damage. During 4 years of TNF-α blocking therapy, 21 (20%) patients developed at least one new fracture. Older age, smoking, higher BASFI, low lumbar spine BMD (Z-score ≤-2), presence of moderate vertebral fractures, and use of anti-osteoporotic treatment at baseline were associated with the development of new fractures. Most fractures were mild and occurred in the thoracic spine. The improvement in lateral spinal mobility and lumbar spine BMD during treatment was significantly less in patients with new fractures (median change of 0.8 vs. 2.8 cm and 0.3 vs. 0.8 Z-score, respectively).
  
  
  CONCLUSIONS
  The prevalence of radiographic vertebral fractures was high in AS patients with active disease. Although clinical assessments and BMD improved significantly, new vertebral fractures still developed during 4 years of TNF-α blocking therapy.
authors.affiliation: Department of Rheumatology and Clinical Immunology, University of Groningen, University Medical Center Groningen, The Netherlands. f.maas@umcg.nl.
authors.forename: Fiona
authors.initials: F
authors.lastname: Maas
authors.affiliation: Department of Rheumatology and Clinical Immunology, University of Groningen, University Medical Center Groningen; and Department of Rheumatology, Medical Center Leeuwarden, The Netherlands.
authors.forename: Anneke
authors.initials: A
authors.lastname: Spoorenberg
authors.affiliation: Department of Rheumatology and Clinical Immunology, University of Groningen, University Medical Center Groningen, The Netherlands.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Brouwer
authors.affiliation: Department of Rheumatology, Medical Center Leeuwarden, The Netherlands.
authors.forename: Anna M
authors.initials: AM
authors.lastname: Schilder
authors.affiliation: Department of Rheumatology and Clinical Immunology, University of Groningen, University Medical Center Groningen, The Netherlands.
authors.forename: Rizwana N
authors.initials: RN
authors.lastname: Chaudhry
authors.affiliation: Department of Rheumatology, Medical Center Leeuwarden, The Netherlands.
authors.forename: Freke
authors.initials: F
authors.lastname: Wink
authors.affiliation: Department of Rheumatology and Clinical Immunology, University of Groningen, University Medical Center Groningen, The Netherlands.
authors.forename: Hendrika
authors.initials: H
authors.lastname: Bootsma
authors.affiliation: Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, The Netherlands.
authors.forename: Eveline
authors.initials: E
authors.lastname: van der Veer
authors.affiliation: Department of Rheumatology and Clinical Immunology, University of Groningen, University Medical Center Groningen; and Department of Rheumatology, Medical Center Leeuwarden, The Netherlands.
authors.forename: Suzanne
authors.initials: S
authors.lastname: Arends
mesh_terms: D000328:Adult; D015519:Bone Density; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D011859:Radiography; D016103:Spinal Fractures / Q000000981:diagnostic imaging / Q000453:epidemiology*; D013167:Spondylitis, Ankylosing / Q000150:complications / Q000188:drug therapy*; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors*
chemical_list: D014409:Tumor Necrosis Factor-alpha