OP0271 HPR ASSESSMENT OF MUSCLE MASS RELATIVE TO FAT MASS AND ITS ASSOCIATION WITH DISEASE ACTIVITY STATUS AND PHYSICAL FUNCTIONING IN RHEUMATOID ARTHRITIS

Abstract

Background Rheumatoid arthritis (RA) is an autoimmune, chronic, progressive, inflammatory disease characterized by symmetrical, destructive polyarthritis and is accompanied by systemic manifestations. RA patients show low appendicular lean mass index (ALMI) and higher fat mass index. Impaired physical function is associated greater with fat mass and the adiposity is an important confounder that may mask true relationships between physical functioning and ALMI (1). Objectives To assess muscle mass relative to fat mass and verify associations this parameter with disease activity status, functional capacity and biologics treatments. Methods 90 RA patients, aged between 40 and 70 years, were recruited and followed for 12 months. Body composition was assessed by total body dual-energy x-ray absorptiometry for measurement of appendicular lean mass index (ALMI, kg/m2) and fat mass index (FMI, kg/m2). Age-, sex-, and race-specific Z- Scores and T-Scores were determined by comparison to published reference ranges. ALMI values were adjusted for FMI (ALMIZ/FMIZ) using a published method. Disease activity was assessed by Disease Activity Score-28 with erythrocyte sedimentation rate (DAS28). RA patients were divided in non-remission (DAS28 2.6). Physical functioning was assessed by Health Assessment Questionnaire (HAQ). Pharmacological treatment used by patients were assessed in patient medical records and the RA were divided in RA patients treated with biologic disease modifying antirheumatic drugs (bDMARDs) and non-treated with bDMARDs. Frequency analysis, Pearson Correlations and GEE analyses were used and statistical significance was considered as p Results Of the 90 patients analyzed, most were women (86.7%,78/91), with mean age of 56.5±7.3 and median disease duration time of 8.5 (3-18) years. At baseline, the mean±SD DAS28 score was 3.7±1.4 and thirty percent of the RA patients (27/90) were treated with bDMARDs. After 12 months, the use of bDMARD did not change (p>0.05), however, mean DAS28 increased over time (mean and SD of 4.0±1.3; p 0.05). Conclusion Low skeletal muscle mass relative to adiposity was common in RA patients. This condition was associated with low physical functioning and its changes over time are associated with disease activity status. The observations that skeletal muscle mass relative to adiposity was affected by remission state stresses and that associated negatively with poor physical functioning demonstrate the importance of adequate control of disease activity in RA established. In addition, from our results, further studies are necessary to elucidate the direct impact of bDMARDs on body composition in RA patients.