ANALYSIS OF INTESTINAL MICROBIOTA IN PATIENTS WITH OSTEOPOROSIS SECONDARY TO RHEUMATOID ARTHRITIS

Abstract

Objectives: To analyse the intestinal microbiota in patients with osteoporosis (OP) secondary to rheumatoid arthritis (RA). Methods: Design: A cross-sectional observational study nested in a prospective cohort of incident RA patients. Patients: Patients with RA (ACR/EULAR 2010) from a prospective baseline cohort (incident cases between 2007-2011), >16 years, from whom information on bone mineral densitometry (BMD) was collected. Protocol: All subjects were evaluated in a specialized outpatient unit. Clinical-analytical variables of the cut-off date and clinical history were registered. Blood, urine, and faeces samples were obtained from all subjects. A BMD was done by dual energy X-ray absorptiometry (DXA) for osteoporosis diagnosis. Variables: Dependent variable: osteoporosis according to World Health Organization (WHO) definitions. The fecal microbiota (continuous var., 0-100%) was analysed using the Ion Torrent S5 next-generation sequencing platform, and the sequences obtained were processed using the QIIME2 (Quantitative Insights Into Microbial Ecology 2) software. Other variables included demographic characteristics, comorbidities, inflammatory activity measured by mean accumulated Disease Activity Score-28 (DAS-28) throughout the disease, severity variables: smoking, erosions, anticitrullinated peptide antibody (ACPA) titres, rheumatoid factor (RF), and physical function measured by HAQ. Treatment with bDMARD (biological disease-modifying antirheumatic drug) and/or sDMARD (synthetic disease-modifying antirheumatic drug).