AB0607 DO HIP STRUCTURAL ANALYSIS MEASUREMENTS PREDICT FRACTURE RISK IN PATIENTS WITH POLYMYALGIA RHEUMATICA?

Abstract

Background:Polymyalgia Rheumatica (PMR) is an inflammatory condition which commonly affects the elderly. Risk of fracture is higher in this group of patients compared to the general population and can lead to increased morbidity and mortality (1). Hip structural analysis (HSA) is a technique that uses dual-energy X-ray absorptiometry (DEXA) images to assess hip bone structure (2).Objectives:To identify whether HSA measurements help predict fracture in patients with PMR.Methods:Data were collected from June 2004 to October 2010 from PMR patients who had a DEXA scan at a District General Hospital. This included hip axis length (HAL), cross-sectional area (CSA), cross-sectional moment of inertia (CSMI), distance from centre of femoral head to centre of femoral neck (D1) and to inter-trochanteric line (D2), mean femoral neck diameter (D3), shaft angle (A) neck/shaft angle (Θ) and proximal femur strength index (SI) and distance from centre of mass of femoral neck to superior neck margin (Y). Fracture was predicted by a series of binomial logistic regression models, adjusted for age and sex. Odds ratios with 95% confidence intervals and area under the receiver operating characteristic curve (AUC) were calculated.Results:714 patients with PMR were identified, 182 were male and the mean age was 70.5. HAL, CSMI, D1, D2, D3, A, Θ, SI and Y were not significant predictors of fracture in regression models; odds ratios are included in Table 1. CSA predicted fracture risk; odds ratio was 0.988 with a 95% confidence interval of 0.980-0.997. The AUC for the CSA regression model was 0.6739.Table 1.Odds ratios of fracture for different HSA parametersHSA ParameterOdds Ratio (95% confidence interval)HAL1.008 (0.982 - 1.035)CSMI1.000 (0.999 - 1.000)CSA0.988 (0.980 - 0.997)D11.029 (0.972 - 1.089)D21.010 (0.981 - 1.040)D31.033 (0.962 - 1.109)Y1.087 (0.966 - 1.223)A0.983 (0.940 - 1.029)Θ1.007 (0.975 - 1.039)SI0.683 (0.406 - 1.150)Conclusion:These data suggest that CSA helps predict the risk of fracture in patients with PMR. HAL, CSMI, D1, D2, D3, A, Θ, SI and Y do not predict fracture risk. Limitations of the study are that it was retrospective and only studied patients who underwent DEXA scans. The study may have been underpowered to detect the impact of some HSA measurements on fracture risk.References:[1]Chatzigeorgiou C, Mackie SL. Comorbidity in polymyalgia rheumatica. Reumatismo. 2018; 70 1:35-43. Available from: http://eprints.whiterose.ac.uk/132109/\\.[2]Kaptoge S, Beck TJ, Reeve J, Stone KL, Hillier TA, Cauley JA, et al. Prediction of Incident Hip Fracture Risk by Femur Geometry Variables Measured by Hip Structural Analysis in the Study of Osteoporotic Fractures. Journal of Bone and Mineral Research. 2008; 23 (12): 1892-1904. Available from: doi: https://doi.org/10.1359/jbmr.080802Disclosure of Interests:None declared.