SAT0246 USING BONE MINERAL DENSITY VERSUS THE RATIO OF BODY MASS INDEX TO BONE MINERAL DENSITY TO PREDICT FRACTURE RISK IN POLYMYALGIA RHEUMATICA
Authors: Khojasta Talash, Marwan Bukhari
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background:</h3> Polymyalgia Rheumatica (PMR) is the commonest inflammatory rheumatic condition that affects the elderly population and treatment with long-term corticosteroids is common<sup>1</sup>. Whilst steroid treatment is beneficial in managing symptoms, it has many side effects including increasing the risk of osteoporosis and hence fractures<sup>2</sup>. There has been recent research that suggests using the ratio of BMD to Body Mass Index (BMI) is a better marker of predicting fracture risk in obese patients than BMD alone<sup>3</sup>. <h3>Objectives:</h3> Our research set out to find out whether BMD alone or the ratio of BMI to BMD is a better predictor of fracture risk in patients with PMR. <h3>Methods:</h3> Data were used from a cohort of PMR patients referred for DEXA scan to a District General Hospital between June 2004 and October 2010. The following were recorded: age, sex, whether a fracture was sustained, whether they had had steroid therapy at any point, BMI, BMD at L1-L4, BMD at femoral neck (left and right) and BMD at hip (left and right). Logistic regression models were fitted using fracture as the dependent variable. The independent variables for the first set of logistic regression models were BMD at each level and for the second set BMI:BMD ratio at the same levels. Data were adjusted for sex and age at scan. Logistic models were compared using area under the ROC curves (AUC). <h3>Results:</h3> 714 patients were used in the study, of whom 532 (75%) were female. Mean age was 70.5 (SD 8.84) with age range 45.8 to 96.5 years. 703 (98%) were recorded to have had steroid therapy at any point. Mean BMI was 28.2 kg/cm<sup>2</sup> (SD 5.24). 156 (22%) had sustained a fracture. Odds ratios and AUC values for each level were as shown in the table. The fit of the models using the BMD alone was superior to the fit of the models using the ratio as the AUC values were greater for BMD alone. <h3>Conclusion:</h3> This study identifies that the BMI:BMD ratio does not provide better indication of fracture risk than BMD alone in our cohort of patients with PMR. We have previously shown that the same is true for patients with rheumatoid arthritis. A limitation of this study is not stratifying by steroid use. Further work will be done to study the role of the ratio in predicting fracture risk in patients with other conditions. <h3>References</h3> [1] Milchert, M., &amp; Brzosko, M. (2017). Diagnosis of polymyalgia rheumatica usually means a favourable outcome for your patient'. Indian journal of medical research, 145(5), 593-600. [2] Michet, C.J., &amp; Matteson, E.L. (2008). Polymyalgia rheumatica. BMJ (Clinical research ed.), 336(7647), 765-9. [3] Tucker, M., (2018, May 18). Simple Ratio May Predict Fracture Risk in Obese Patients. Retrieved from https://www.medscape.com/viewarticle/896882 <h3>Disclosure of Interests:</h3> Khojasta Talash: None declared, Marwan Bukhari Speakers bureau: Bristol-Myers Squib, UCB celltech, Roche/Chugai, Pfizer, Abbvie, Merck, Mennarini, Sanofi-aventis, Eli-Lilly, Janssen and Novartis.