AB0133 LATE-ONSET AND BONE LOSS IN RHEUMATOID ARTHRITIS: WHAT FACTORS SHOULD WE CONSIDER?
Authors: K. Maatallah, M. Yasmine, H. Ferjani, W. Triki, D. Ben Nsib, D. Kaffel, W. Hamdi
Journal: Annals of the Rheumatic Diseases (2021)

Background: Rheumatoid arthritis (RA) is an inflammatory rheumatism that causes alterations in bone components through the increased production of pro-inflammatory cytokines. Besides traditional risk factors of osteoporosis (OP), elderly RA patients are at higher risk of progressive decline in bone mineral density resulting from the disease. Objectives: This study aimed to determine factors associated with bone loss in late-onset RA patients. Methods: A cross-sectional study including patients with RA (according to ACR/EULAR classification criteria) in whom disease onset was after age 65 years. Sociodemographic data, daily calcium intake, and menopausal state were recorded. The characteristics of the disease were transcribed, including inflammatory markers (erythrocyte sedimentation rate (ESR) and C- reactive protein (CRP)), the disease activity assessed by Disease Activity Score 28 (DAS28), seropositivity for anti-cyclic citrullinated peptide antibody (ACPA) and rheumatoid factor (RF), and treatment modalities (cumulative dose of corticosteroids and Methotrexate). Bone mineral density (BMD) was assessed by Dual-energy X-ray absorptiometry. The risk of hip fracture (HF) and major osteoporotic fracture (MOF) after ten years were assessed using the fracture risk assessment tool (FRAX). Patients were divided into two groups (G1 with bone mineral loss (BML) and G2 without BML). Statistical analysis was performed using Kruskal-Wallis Test and chi-square. The level of significance was fixed for p&lt; 0.05. Results: The study included 58 late-onset RA patients with a female predominance (sex ratio M/F=0.3). The mean age was 71.6 ± 5.9 years [65-85], and the mean disease duration was 3.1 ±2.9 years [0-15]. The mean calcium intake was 416.4± 168.6 mg per day [168-1043]. The mean BMD was 1.5 g/cm 2 [0.1-28.3] at the vertebral site and 0.7±0.2 g/cm [-0.1,1.2] at the femoral site. Bone loss was found in 55.2% of cases and was significantly associated with age (p=0.022) and longer disease duration (p=0.015). Similarly, there was a positive correlation between CRP and BML (p=0.023). However, bone loss was not correlated to sex (p=0.865), RF and ACPA positivity (p=0.9, p=0.1 respectively), or to coxitis (p=1). Similarly, disease activity, body mass index, and calcium intake were comparable between the two groups (p=0.311, p=0.179, p=0.099, respectively). G1 had a higher incidence of fractures without reaching a statistically significant correlation (63.2% in G1 and 51.3% in G2, p=0.393). Also, G1 had a higher risk of MOF (p=0.003) but not with a higher risk of HP (p=0.127). Regarding treatment modalities, the BML was significantly correlated to non-steroidal anti-inflammatory drug (NSAIDs) intake (85.7% in G1 and 37.8% in G2, p=0.001), but was not correlated to the cumulative dose of corticosteroids (p=0.384) and Methotrexate (p=0.054). Conclusion: Our study showed that age, disease duration, NSAIDs, and inflammation were risk factors for a bone mineral loss in late-onset RA. Screening for these factors would be useful as part of an ideal form of fracture risk management. Disclosure of Interests: None declared