Which measuring site in ankylosing spondylitis is best to detect bone loss and what predicts the decline: results from a 5-year prospective study

• Published in: Arthritis research & therapy 2017-12, Vol.19 (1), p.273-273, Article 273
• Main Authors: Deminger, Anna, Klingberg, Eva, Lorentzon, Mattias, Geijer, Mats, Göthlin, Jan, Hedberg, Martin, Rehnberg, Eva, Carlsten, Hans, Jacobsson, Lennart T, Forsblad-d'Elia, Helena
• Format: Article
• Language: English
• Subjects: Ankylosing spondylitis; Bone density; Bone mineral density; Care and treatment; Development and progression; Health aspects; Inflammation; Longitudinal study; Osteoporosis; Reumatologi och inflammation; Rheumatology and Autoimmunity
• ISSN: 1478-6362; 1478-6354; 1478-6362
• DOI: 10.1186/s13075-017-1480-0

Studies have shown increased prevalence of osteoporosis and increased risk for vertebral fractures in patients with ankylosing spondylitis (AS). Measurements of bone mineral density (BMD) in the lumbar spine anterior-posterior (AP) projection may be difficult to interpret due to the ligamentous calcifications, and the lateral projection might be a better measuring site. Our objectives were to investigate BMD changes after 5 years at different measuring sites in patients with AS and to evaluate disease-related variables and medications as predictors for BMD changes. In a longitudinal study, BMD in Swedish AS patients, 50 ± 13 years old, was measured with dual-energy x-ray absorptiometry (DXA) at the hip, the lumbar spine AP and lateral projections, and the total radius at baseline and after 5 years. Patients were assessed with questionnaires, blood samples, and spinal radiographs for grading of AS-related alterations in the spine with the modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS) and assessment of vertebral fractures by the Genant score. Multiple linear regression analyses were used to investigate predictors for BMD changes. Of 204 patients included at baseline, 168 (82%) were re-examined after 5 years (92 men and 76 women). BMD decreased significantly at the femoral neck and radius and increased significantly at the lumbar spine, both for AP and lateral projections. Mean C-reactive protein during follow-up predicted a decrease in the femoral neck BMD (change in %, β = -0.15, p = 0.046). Use of bisphosphonates predicted an increase in BMD at all measuring sites (p