Background Rheumatoid arthritis (RA) is associated with changes in body composition and abdominal adiposity (sarcopenia and overfat phenotype) that have consequences on disease mortality and morbidity. The relation of this modified body composition with disease activity, radiological damage and endothelial dysfunction in RA has not been completely explored.
Methods 216 subjects, 111 RA patients and 105 age and sex-matched healthy controls were included in this cross-sectional study. Anthropometric and demographic characteristics, cardiovascular risk measurement through SCORE index, C-reactive protein (CRP), Disease Activity Score (DAS28), Health Assessment Questionnaire (HAQ), and radiological damage through Sharp index were determined. Quantification of visceral and parietal abdominal fat area was assessed using magnetic resonance imaging. Total body composition, total and regional lean mass and fat mass, and fat free mass index were measured by dual energy X-ray absorptiometry. The presence of sarcopenia or overfat phenotype was established. Endothelial dysfunction was assessed through brachial artery flow-mediated dilatation sonography. Multivariate analysis was performed to define the relation of this body composition with disease characteristics.
Results 1) Body composition.Visceral/subcutaneous adipose tissue index determined by resonance imaging was not different between female patients and controls, only in males tended to be lower (β -0.23 [-0.50-0.04], p=0.08). Fat mass values were inferior in female RA patients (β-2.4 [-4.7-0.07], p=0.04) than in controls. Fat free mass index did not show differences between female controls and patients, but a tendency to be lower in male patients (β -1.4 [-3.0--0.1], p=0.06) was found. Appendicular/total lean mass and appendicular/trunk lean mass indexes were inferior in female patients when compared to controls (β-0.013 [-0.020--0.005], p=0.00). We have not found a greater presence of sarcopenia, overfat or sarcopenic obesity in patients. 2) Radiological damage. Sarcopenic patients demonstrated a higher Sharp index (β 11. 5 [0.24-22,7], p= 0.04) after adjusting by DAS28, age and disease duration. This was not found with overfat or sarcopenic obesity phenotypes. 3) Disease activity. Overfat phenotype in RA patients was associated with higher levels of DAS28 (β 0.53 [0.10-0.96], p=0.02) and CRP. In contrast, sarcopenic RA patients did not demonstrate higher disease activity values. Sarcopenic-obese patients showed higher CRP values (β 9.9 [0.5-19.4], p=0.04), but this was not found with DAS28. 4) Endothelial dysfunction. Although RA patients showed a statistical inferior flow-mediated dilatation when compared to controls (6.5±11.7 vs 11.7±9.5 mm, p=0.01), this endothelial dysfunction was not related with changes in body composition or in abdominal adiposity. On the other hand, the presence of sarcopenia (β 4.7 [0.2-9.1], p=0.04) and sarcopenic obesity (β 5.5 [0.3-10.8], p=0.04) was associated with higher SCORE values.
Conclusions Body composition and abdominal adiposity changes that occurs in RA patients are related with its radiological damage, disease activity and cardiovascular risk.
Disclosure of Interest None Declared