SAT0450 GLUCOCORTICOID-INDUCED OSTEOPOROSIS IN PATIENTS WITH CHRONIC INFLAMMATORY RHEUMATIC DISEASES: A MULTIVARIATE LINEAR REGRESSION ANALYSIS IDENTIFYING PREDICTIVE FACTORS FOR LOW BONE MASS
Authors: E. Wiebe, D. Freier, D. Huscher, R. Biesen, S. Hermann, F. Buttgereit
Journal: Annals of the Rheumatic Diseases (2020)

Background: Rheumatic diseases are associated with increased systemic bone loss and fracture risk related to chronic inflammation, disease-specific, general and demographic risk factors as well as treatment with glucocorticoids (GC). Yet, there is evidence that GCs may, by adequately suppressing systemic inflammation, also have a positive effect on bone mineral density (BMD) and fracture risk 1 . Objectives: The purpose of this study was to investigate the prevalence of osteoporosis and fragility fractures in patients with inflammatory rheumatic diseases and to analyze the impact that treatment with GCs, other known risk factors and preventive measures have on bone health in these patients. Methods: Rh-GIOP is an ongoing prospective observational study collecting and analyzing disease- and bone-related data from patients with chronic inflammatory rheumatic diseases and psoriasis treated with GCs. In this cross-sectional analysis, we evaluated the initial visit of 1091 patients. A multivariate linear regression model with known or potentially influential factors adjusted for age and sex was used to identify predictors of BMD as measured by dual-energy X-ray absorptiometry (DXA). Multiple imputation was applied for missing baseline covariate data. Results: In the total cohort of 1091 patients (75% female of which 87.5% were postmenopausal) with a mean age of 62.1 (±13.2) years, the prevalence of osteoporosis by DXA was 21.7%, while fragility fractures have occurred in 31.2% of the study population (6.7% vertebral, 27.7% non-vertebral). Current GC therapy was common (64.9%), with a median daily dose of 5.0mg [0.0;7.5], a mean life-time total GC dose of 17.7g (±24.6), and a mean GC therapy duration of 7.8 years (±8.5). Bisphosphonates were the most commonly used anti-osteoporotic drug (12.6%). Multivariate analysis showed that BMD as expressed by the minimum T-Score at all measured sites was negatively associated with higher age, female sex and menopause as well as Denosumab and Bisphosphonate treatment. A positive association with BMD was found for body mass index as well as current and life-time (cumulative) GC dose. While comedication with proton-pump-inhibitors significantly predicted low bone mass, concomitant use of non-steroidal anti-inflammatory drugs showed a positive association with BMD. Of the measured bone-specific laboratory parameters, higher alkaline phosphatase levels were determinants of low DXA-values, while the association was positive for gamma-glutamyltransferase. BMD was neither predicted by duration of GC treatment nor by treatment with disease modifying anti-rheumatic drugs. Predictive variables for BMD differed at the respective anatomical site. While treatment with Denosumab predicted low bone mass at the lumbar spine and not at the femoral neck, the opposite was true for health assessment questionnaire (HAQ) score. Current and life-time GC-dose as well as direct sun-exposure of more than 30 minutes daily were positively associated with bone mass at the femoral sites only. Conclusion: This cross-sectional analysis of a prospective cohort study quantified the prevalence of osteoporosis and identified predictive variables of BMD in patients with rheumatic diseases. Multivariate analyses corroborated low BMD to be predicted by traditional factors like age, female sex and menopause but showed current and well as life-time GC dose to be positively associated with BMD in our cohort of patients with chronic inflammatory rheumatic diseases. This suggests that optimal management of disease activity with GCs might be beneficial in order to avoid bone loss due to inflammation. References: [1]Güler-Yüksel et al. “Glucocorticoids, Inflammation and Bone.” Calcified Tissue International (January 08 2018). Disclosure of Interests: Edgar Wiebe: None declared, Desiree Freier: None declared, Dörte Huscher: None declared, Robert Biesen: None declared, Sandra Hermann: None declared, Frank Buttgereit Grant/research support from: Amgen, BMS, Celgene, Generic Assays, GSK, Hexal, Horizon, Lilly, medac, Mundipharma, Novartis, Pfizer, Roche, and Sanofi.