Ankylosing spondylitis confers substantially increased risk of clinical spine fractures: a nationwide case-control study
- 749 Downloads
Ankylosing spondylitis (AS) leads to osteopenia/osteoporosis and spine rigidity. We conducted a case-control study and found that AS-affected patients have a 5-fold and 50 % increased risk of clinical spine and all clinical fractures, respectively. Excess risk of both is highest in the first years and warrants an early bone health assessment after diagnosis.
Ankylosing spondylitis (AS) is related to spine rigidity and reduced bone mass, but data on its impact on fracture risk are scarce. We aimed to study the association between AS and clinical fractures using a case-control design.
From the Danish Health Registries, we identified all subjects who sustained a fracture in the year 2000 (cases) and matched up to three controls by year of birth, gender and region. Clinically diagnosed AS was identified using International Classification of Diseases, 8th revision (ICD-8; 71249), and International Classification of Diseases, 10th revision (ICD-10; M45) codes. We also studied the impact of AS duration. Conditional logistic regression was used to estimate crude and adjusted odds ratios (ORs) for non-traumatic fractures (any site, clinical spine and non-vertebral) according to AS status and time since AS diagnosis. Multivariate models were adjusted for fracture history, socio-economic status, previous medical consultations, alcoholism and use of oral glucocorticoids.
We identified 139/124,655 (0.11 %) AS fracture cases, compared to 271/373,962 (0.07 %) AS controls. Unadjusted (age- and gender-matched) odds ratio (OR) were 1.54 [95 % confidence interval (95 %CI) 1.26–1.89] for any fracture, 5.42 [2.50–11.70] for spine and 1.39 [1.12–1.73] for non-vertebral fracture. The risk peaked in the first 2.5 years following AS diagnosis: OR 2.69 [1.84–3.92] for any fracture.
Patients with AS have a 5-fold higher risk of clinical spine fracture and a 35 % increased risk of non-vertebral fracture. This excess risk peaks early, in the first 2.5 years of AS disease. Patients should be assessed for fracture risk early after AS diagnosis.
KeywordsAnkylosing Bone Electronic health records Epidemiology Fractures Spondylitis
Statistics Denmark is acknowledged for the help with the acquisition of the data.
DPA, NKA and CC receive partial funding from the Oxford NIHR Musculoskeletal Biomedical Research Unit. DPA receives partial funding from the MRC Lifecourse Epidemiology Unit (Southampton), the IDIAP Jordi Gol Primary Care Research Institute and the URFOA (IMIM, Parc de Salut Mar, Barcelona). DPA receives funding from the NIHR Clinician Scientist Award scheme.
The data retrieval was sponsored by a grant from the Danish Medical Research Council (Grant number 22-04-0495).
Conflicts of interest
- 13.Montala N, Juanola X, Collantes E, Munoz-Gomariz E, Gonzalez C, Gratacos J, Zarco P, Sueiro JL, Mulero J, Torre-Alonso JC, Batlle E, Carmona L (2011) Prevalence of vertebral fractures by semiautomated morphometry in patients with ankylosing spondylitis. J RheumatolGoogle Scholar
- 15.Arends S, Spoorenberg A, Bruyn GA, Houtman PM, Leijsma MK, Kallenberg CG, Brouwer E, van der Veer E (2011) The relation between bone mineral density, bone turnover markers, and vitamin D status in ankylosing spondylitis patients with active disease: a cross-sectional analysis. Osteoporos Int 22:1431–1439PubMedCentralPubMedCrossRefGoogle Scholar
- 19.van der Weijden MA, Claushuis TA, Nazari T, Lems WF, Dijkmans BA, van der Horst-Bruinsma IE (2012) High prevalence of low bone mineral density in patients within 10 years of onset of ankylosing spondylitis: a systematic review. Clin RheumatolGoogle Scholar
- 20.Muñoz-Ortego J, Vestergaard P, Blanch J, Wordswoth P, Judge A, Kassim M, Arden N, Cooper C, Díez-Perez A, Prieto-Alhambra D (2012) Ankylosing spondylitis is associated with an increased risk of osteoporotic fractures: a population-based cohort study. Arthritis Rheum 64Google Scholar
- 21.Muñoz-Ortego J, Vestergaard P, Rubio JB, Wordsworth P, Judge A, Javaid MK, Arden NK, Cooper C, Diez-Perez A, Prieto-Alhambra D (2014) Ankylosing spondylitis is associated with an increased risk of vertebral and non-vertebral clinical fractures: a population-based cohort study. J Bone Miner Res 29(8):1770–1776PubMedCrossRefGoogle Scholar