THU0069 RHEUMATOID CACHEXIA ASSESSED BY BODY COMPOSITION IS ASSOCIATED WITH WORSE DISEASE IN RHEUMATOID ARTHRITIS PATIENTS WITH NORMAL BODY MASS INDEX
Authors: Jian-Zi Lin, Lijuan Yang, Le-Feng Chen, LI Qian-Hua, MA Jianda, Yingqian Mo, Lie Dai
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background:</h3> Abnormal body composition (BC) has been reported in rheumatoid arthritis (RA) patients with normal body mass index (BMI). Rheumatoid cachexia (RC) was found in RA patients with a decrease in muscle mass and an increase or limited change in fat mass, resulting in no or limited changes in BMI. However, there is no consensus on the clinical criteria for its diagnosis, and the clinical significance of RC has not been well known until now. <h3>Objectives:</h3> To investigate the characteristics of BC in RA patients with normal BMI and the association between RC and disease characteristics. <h3>Methods:</h3> Consecutive RA patients were recruited and clinical data including disease activity, function and radiographic assessment were collected. BC was assessed by bioelectric impedance analysis. RC was defined as those with concurrent overfat (body fat percentage ≥25% for men and ≥35% for women) and myopenia (appendicular skeletal muscle mass index ≤7.0 kg/m<sup>2</sup> in men and ≤5.7 kg/m<sup>2</sup> in women) in this study. Multivariate logistic regression analysis was performed to identify the association between disease characteristics and RC in RA patients with normal BMI, following the step-forward selection rule that variables were included in the equation when the P value was &lt;0.05 or removed when the P value was &gt;0.10. <h3>Results:</h3> <b>1.</b> There were 516 RA patients recruited, with 13.8% RC as well as 17.4% underweight, 56.4% normal weight, 22.5% overweight and 3.7% obese respectively. Among 71 RA patients with RC, 73.2% showed normal BMI, while 2.8% underweight, 22.5% overweight and 1.4% obese. Among RA patients with normal BMI (n=291), 17.9% patients showed RC, 28.1% showed normal fat but myopenia, 1.4% showed overfat but non-myopenia, while 52.6% showed both normal fat and non-myopenia. <b>2.</b> For RA patients with normal BMI, compared with those with both normal fat and non-myopenia, RA patients with RC were older with longer disease duration, higher disease activity indicators including 28TJC, PtGA, PrGA, PainVAS, ESR, CRP, DAS28-CRP, SDAI and CDAI, higher functional indicators including HAQ-DI and rate of functional limitation, higher radiographic assessment including mTSS, JSN and JE subscores, higher rate of previous use of glucocorticosteroids (75.0% vs. 52.3%), and higher prevalence of hypertension (25.0% vs. 7.8%). Further compared with those with normal fat but myopenia, RA patients with RC showed the similar results with significantly longer disease duration, higher CRP, HAQ-DI, mTSS, JSN subscore, JE subscore, and higher rate of previous use of glucocorticosteroids (all <i>P</i>&lt;0.0167, bonferroni correction). <b>3.</b> Multivariate logistic regression analysis showed that CRP (<i>OR</i>=1.024, 95%<i>CI</i>: 1.009-1.040), mTSS (<i>OR</i>=1.017, 95%<i>CI</i>: 1.010-1.025), previous use of glucocorticosteroids (<i>OR</i>=2.605, 95%<i>CI</i>: 1.217-5.575), and suffering from hypertension (<i>OR</i>=3.462, 95%<i>CI</i>: 1.448-8.274) were positively associated with RC in RA patients with normal BMI. <h3>Conclusion:</h3> Our data show rheumatoid cachexia is associated with worse disease including RA disease activity, functional limitation and radiographic joint damage, which imply that RC should be emphasized especially in RA patients with normal BMI. <h3>Acknowledgement:</h3> This work was supported by National Natural Science Foundation of China (no.&nbsp;81671612&nbsp;and 81801606), Guangdong Natural Science Foundation (no. 2017A030313576, 2017A030310236 and 2018A030313541) and Guangdong Medical Scientific Research Foundation (no. A2017109). <h3>Disclosure of Interests:</h3> None declared