1331: Risk Factors for Osteoporotic Fracture in Women with Established Long-Term Rheumatoid Arthritis

Felipe Freire da Silva¹, Gisela Machado², ana Medeiros³, Karina Bonfiglioli⁴, Andrea Shimabuco², Liliam Takayama⁵, Rosa Pereira⁶ and Diogo Domiciano⁷, ¹FMUSP, Salvador, Brazil, ²FMUSP, São Paulo, Brazil, ³Faculdade de Medicina da Universidade de São Paulo, São Jose Dos Campos, Brazil, ⁴Hospital das Clínicas, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil, ⁵University of São Paulo, São Paulo, Brazil, ⁶Bone Metabolism Laboratory, Rheumatology Division, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil, ⁷Hospital das Clinicas, Rheumatology Division, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil

Background/Purpose: Low bone mineral density (BMD) is a predictor of osteoporotic fracture. However, individuals with Rheumatoid Arthritis (RA) who sustain "osteoporosis-related" fractures frequently have normal BMD or osteopenia. Studies addressing risk factors for fracture in RA patients are quite heterogeneous and do not usually include a more comprehensive assessment of variables potentially associated with fracture. Therefore, our aim was to investigate risk factors for fractures, including variables related to disease activity of RA but also those related to bone metabolism: clinical data, laboratory tests and densitometric parameters (bone mass, body composition and trabecular bone score - TBS) in women with long-term established RA.

Methods: Women diagnosed with RA (ACR, 2010) were consecutively selected from a tertiary hospital outpatient clinic. The evaluation consisted of: clinical questionnaire [with assessment of HAQ (Health Assessment Questionnaire) and iPAQ (International Physical Activity Questionnaire)], body mass index (BMI), RA activity composite indices (DAS28, SDAI and CDAI), laboratory tests (C-reactive protein – CRP, parathyroid hormone - PTH, 25-hydroxyvitamin D and bone turnover markers), BMD, body composition, TBS and Vertebral Fracture Assessment – VFA by DXA. Logistic regression models were constructed to define the variables independently associated with vertebral and non-vertebral fractures, separately.

Results: 265 women (54±12.8 years), with a mean disease duration of 16±10 years, were included in the study. Of these, 19.2% had osteoporosis, 45.7% osteopenia, 30.6% vertebral fractures and 17.4% non-vertebral fractures. In multivariate logistic regression, after adjustments for age, height, rheumatoid factor/ACPA positivity, cumulative prednisone dose, menopause, and use of osteoporosis medications, TBS values (OR 1.61; 95% CI 1.09 -2.38; p=0.017, per each 1SD decrease), CRP (OR 1.54; 95% CI: 1.15-2.08; p=0.004, per each 10mg/dL increase) and PTH (OR 1.24; 95% CI: 1.05-1.45, p=0.009, per each 10mg/dL increase) were risk factors for vertebral fracture, whereas sarcopenia (OR 3.37; 95% CI 1.31-8.69; p=0.012), BMI (OR 0.90; 95% CI 0.82-0.98; p=0.020) and hip BMD (OR 2.08; 95% CI 1.15-3.85; p=0.015, per each 1 SD decrease) were associated with non-vertebral fracture. ROC curve analysis showed better accuracy of TBS for detection of vertebral fractures. On the other hand, total hip BMD had a greater area under curve for non-vertebral fractures.

Conclusion: In women with long-term established RA, low hip BMD and sarcopenia were associated with non-vertebral fractures, whereas reduced trabecular bone quality of the spine (low TBS), inflammatory activity (represented by higher CRP) and higher PTH were associated with vertebral fracture. These findings reinforce that factors linked to osteoporotic fractures are different between skeletal sites (vertebral and non-vertebral) in women with RA and should be recognized for the proper management of osteoporosis in these patients.

Disclosures: F. Freire da Silva, None; G. Machado, None; a. Medeiros, None; K. Bonfiglioli, None; A. Shimabuco, None; L. Takayama, None; R. Pereira, None; D. Domiciano, None.