RELATIONSHIP BETWEEN BONE MINERAL DENSITY, INFLAMMATORY ACTIVITY AND AUTOIMMUNITY IN A COHORT OF EARLY RHEUMATOID ARTHRITIS PATIENTS

Background: The etiology of bone loss in Rheumatoid Arthritis (RA) is multifactorial and systemic inflammation plays a relevant role. Recently, a relationship between autoimmunity and bone mineral density (BMD) has been described in patients with RA. Objectives: To study BMD and biochemical parameters of bone metabolism in a cohort of patients with early rheumatoid arthritis, and assess the relationship between them and autoimmunity and other markers of inflammation. Methods: A prospective longitudinal study was performed. 128 patients from an early Rheumatoid Arthritis Unit (ERAU) were included. All of them fullfilled ACR 2010 classification criteria for RA. Demographic, clinical, biochemical, immunological, radiological and densitometric data, and also inflammatory activity index DAS 28, HAQ functional index, were collected. Any value >20 IU/mL for RF and >30 IU/mL for ACPA was defined as positive. Results: Between January 2009 and June 2017, 801 patients were evaluated in our ERAU. After two years of follow-up, the most frequent definitive diagnoses were: Early RA 221 (27.6%), Undifferentiated Arthritis 97 (12.1%), Psoriatic Arthritis 62 (7.7%), Spondyloarthritis 54 (6.7%) and autoimmune Diseases 28 (3.4%). From the 128 patients with early rheumatoid arthritis evaluated, 104 (81.9%) were ACPA positive and 98 (77.2%) FR positive. The mean BMD in the total column was 0.96 ±0.14 g/cm2 and in the femoral neck was 0.76 ±0.12 g/cm2. No correlation of BMD with autoimmunity markers was found in either of the two locations studied, while a negative relationship between BMD and the PCR inflammation marker (BMD femoral neck: rho-0.203, p = 0.027 and BMD lumbar spine rho =-0.27, p 0.003) was found. The BMD did not correlate with DAS28 nor the HAQ index. The mean baseline serum calcidiol value was 20.7±8 ng/ml, and a negative correlation of basal serum calcidiol with the functional HAQ index was observed (rho=-0.23, p= 0.008). No correlation between other autoimmunity (FR and ACPA) and inflammation (VSG, PCR and DAS 28) markers and vitamin D was found. Conclusion: The BMD in patients with early rheumatoid arthritis of our cohort correlates with the PCR inflammation marker. Unlike other studies shows, in our cohort, serological autoimmunity factors do not have shown to have an independent effect on BMD. References: [1]Llorente I, Merino M, Ortiz AM, et al. Anti-citrullinated protein antibodies are associated with decreased bone mineral density: baseline data from a register of early arthritis patients. Rheumatol Int (2017) 37:799–806 Disclosure of Interests: Sara Garcia Carazo: None declared, Diana Peiteado: None declared, Alejandro Villalva: None declared, Laura Nuno: None declared, Mariana Diaz: None declared, Alejandro Balsa Grant/research support from: BMS, Roche, Consultant of: AbbVie, Gilead, Lilly, Pfizer, UCB, Sanofi, Sandoz, Speakers bureau: AbbVie, Lilly, Sanofi, Novartis, Pfizer, UCB, Roche, Nordic, Sandoz, Pilar Aguado: None declared