Background The risk of osteoporosis in patients with rheumatoid arthritis (RA) is well described and may be associated with genetic and environmental factors. The frequency of generalized osteoporosis in different studies is variable.
Objectives The aim of the study was to investigate the frequency of osteoporosis as well as to describe the risk factors in RA population.
Methods Retrospective study, including patients with RA who had at least 2 densitometries in their follow up. We collected demographic characteristics, use of glucocorticoids (GC), other medications and antibody profile. Variables were compared between groups with or without osteoporosis. The frequency of osteoporosis was calculated according to the T-score and logistic regression was performed to explore the association of osteoporosis and relevant variables. Statistical analysis was performed using R software version 3.2.1. Baseline characteristics were compared between groups of patients (osteoporosis in the lumbar spine, femoral neck and hip) defined according to the T-score results. We used x2 or Fisher test for categorical variables as appropriate and Wilcoxon test for continuous variables. A logistic regression model was used to explore the relationship between osteoporosis and variables that could contribute as risk factors.
Results One hundred and five patients were included, 96.2% were women, RA evolution of 7 (IQR 8) years. The frequency of osteoporosis was: lumbar spine 55.2%, hip 12%, and femoral neck 25.7%. Patients with lumbar spine osteoporosis had higher age (62 vs 58 years, p=0.13), lower weight (57 vs 63.8 kg, p=0.00004) and higher FRAX scores (26.5 vs 11.5, p=0.004; 8.5 vs 2.4, p=0.02). The associated risk factors were: weight (OR 1.09, 95% IC 1.03–1.15, p=0.001), GC use (OR 4.36, 95% IC 1.0–19.89, p=0.049), menopause (OR 22.78, 95% IC 2.73–190.12, p=0.003). There was no association with disease activity (DAS28-ESR) (OR 0.64, 95% IC 0.42–0.96, p=0.049).
Conclusions The frequency of lumbar spine osteoporosis in our population was similar to that reported in previous studies (38.9%>50%). In our study only significant association with weight, GC use and menopause was observed
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Disclosure of Interest None declared