Abstract
Objective Adverse changes in body composition are increasingly being recognized in Rheumatoid Arthritis (RA) patients. This study aims to explore the relationship between RA's disease activity, disease impact, and functional disability with bioelectrical phase angle (PhA) and appendicular skeletal muscle mass index (ASMI).
Methods RA patients were recruited at a tertiary hospital in Portugal. Disease Activity Score in 28 Joints calculated with erythrocyte sedimentation rate (DAS28-ESR) and CReactive Protein (DAS28-CRP) were used to assess disease activity. The impact of disease and functional status were evaluated using the Rheumatoid Arthritis Impact of Disease (RAID) questionnaire and the Health Assessment Questionnaire (HAQ), respectively. Body composition was measured by bioelectrical impedance analysis (BIA). PhA was stratified into tertiles, and ASMI was classified according to the EWGSOP2 criteria.
Results 104 patients with RA were included (74.0% female, 60.9 ± 9.6 years old). RAID scores were significantly lower in patients in the highest PhA group (PhA-T3) compared with patients with lower PhA tertiles (PhA-T2 and PhA-T1: p<0.001). HAQ scores were also significantly lower in patients in the highest PhA group (PhA-T3) than in patients in the lower PhA tertiles (PhA-T2: p=0.033; PhA-T1: p<0.001). Median DAS28-ESR and DAS28-CRP were lower among patients with higher PhA, but the difference did not reach statistical significance (p=0.069 and p=0.159). No differences were found between the groups of ASMI for DAS28-ESR (p=0.625), DAS28-CRP (p=0.970), RAID (p=0.300), and HAQ (p=0.514) scores.
Conclusion A lower PhA was associated with increased disease impact and more significant functional disability in RA patients.
