OP0244 DISEASE SEVERITY IS ASSOCIATED WITH OSTEOPOROSIS AND FRAGILITY FRACTURES IN PATIENTS WITH SYSTEMIC SCLEROSIS

Abstract

BackgroundPatients with systemic sclerosis (SSc) are at an increased risk for osteoporosis (OP) and associated fragility fractures [1]. The prevalence of osteodensitometric OP has been estimated to range from 16% to 60% [2]. However, the risks factors and the mechanisms driving bone loss in patients with SSc remain elusive. The role of “general” determinants such as higher age and low body mass index (BMI) is well established (3) but their interaction with disease-specific factors is unclear. An association between OP and the cutaneous subset (diffuse or limited skin extent) (3, 4) or disease-specific antibodies (anti-centromere or anti-topoisomerase I antibodies) (5, 6) is controversial.ObjectivesOur objectives in the present study were.(i)to evaluate the prevalence of clinical OP and fragility fractures in a large population of SSc patients;(ii)and to identify potential disease-specific factors for OP in this population.MethodsThis cross-sectional study was based on two large European prospective cohorts of SSc patients with retrospective collection of bone health data. OP was defined as the presence of a T-score below -2.5 at femoral neck or lumbar spine and/or a previous major osteoporotic fracture and/or the prescription of anti-osteoporotic therapy. Long-term therapy with glucocorticoids (GCs) was defined by a daily prednisone equivalent dose above 2.5 mg for more than 3 months. Age, female sex, BMI and treatment with proton pump inhibitors (PPIs) as predefined risk factors according to published evidence, as well as clinically relevant factors associated with a p-value <0.05 in univariable analyses, after correction for multiple comparison, were implemented into a multivariable logistic regression model.ResultsA total of 932 patients fulfilling the ACR/EULAR 2013 classification criteria were included in the study, followed prospectively in two university hospitals: Lille (n=485) and Berlin (n=447; of which 72 were patients of the Rh-GIOP prospective cohort). The two cohorts were studied separately. The prevalence of OP was 32% in Berlin and 23% in Lille (p=0.003), fragility fractures occurred in 22% and 18% respectively.Multivariable analysis in the Berlin cohort (Figure 1A) indicated that higher age (OR 1.05 [95%CI 1.03 to 1.07], p<0.001), female sex (OR 2.70 [95%CI 1.29 to 5.65], p=0.009), diffuse skin extent (OR 5.03 [95%CI 2.50 to 10.10], p<0.001), low BMI (OR 0.94 [95%CI 0.88 to 0.99], p=0.009), WHO-FC III-IV dyspnea (OR 2.06 [95%CI 1.16-3.67], p=0.014), receiving GCs (OR 1.78 [95%CI 1.10 to 3.17], p=0.026) or PPIs (OR 1.87 [95%CI 1.10 to 3.17], p=0.020) were associated with OP.In the Lille cohort, multivariable analysis (Figure 1B) confirmed the association of OP with higher age (OR 1.06 [95%CI 1.04 to 1.08], p<0.001), GCs use (OR 4.48 [95%CI 2.42 to 8.26], p<0.001), and with anti-topoisomerase I antibody positivity (OR 2.22 [95%CI 1.18 to 4.16], p=0.013).ConclusionOur data support a multifactorial etiopathogenesis of OP in SSc: besides common risk-factors for OP such as higher age, female sex, and BMI, several disease specific characteristics were associated with OP, such as SSc severity as reflected by diffuse skin extent and presence of antitopoisomerase I antibodies as well as severe dyspnea and SSc treatment (PPIs and GCs). These findings help to identify patients with SSc at particular risk for OP in clinical practice.