Background Patients with rheumatoid arthritis (RA) show a lower muscle mass1 and higher prevalence of sarcopenia than healthy individuals. A prospective observational study (CHIKARA study, registration number: UMIN000023744) was started to clarify the influence of changes in disease activity for sarcopenia.
Objectives We investigated the relationship between sarcopenia and disease activity at baseline in patients with RA.
Methods We analyzed baseline data from the CHIKARA study (Correlation research of sarcopenia, skeletal muscle and disease activity in rheumatoid arthritis). Sarcopenia was diagnosed using the criteria of the Asia Working Group on Sarcopenia2. Muscle mass, body fat mass, total body water, bone mass, and basal metabolic rate were measured using a body composition analyzer (MC-780A; TANITA, Tokyo, Japan). We investigated correlations between sarcopenia and disease activity (DAS28-ESR, SDAI, physical function (HAQ), and laboratory data using uni- and multivariate analyses.
Results Participants comprised 100 patients with RA (females, 78%; mean age, 66.1 years). Mean disease duration was 5.5 years, DAS28-ESR was 3.55, and the percentage of subjects with sarcopenia was 28%. Table 1 shows risk factors for sarcopenia. Sarcopenia correlated with weight, body mass index (BMI), body fat mass, muscle mass, basal metabolic rate, Steinbrocker stage, CRP bone mass, and matrix metalloprotease (MMP)-3 on univariate analysis. Glucocorticoid dosage, rheumatoid factor, and anti-CCP antibody showed no correlation with sarcopenia. BMI, body fat mass, and MMP-3 were identified as independent risk factors on multivariate analysis. MMP-3 over 90.7 ng/ml was a risk factor for sarcopenia by ROC curve analysis (odds ratio, 3.09; p=0.023).
Conclusions The percentage of sarcopenia was 28% in patients with RA. Low BMI, high body fat mass, and high MMP-3 represented independent risk factors for sarcopenia. A relationship between MMP-3 and sarcopenia was indicated by this study.
Inui K., Koike T., Tada M., et al. Sarcopenia is apparent in patients with rheumatoid arthritis, especially those with biologics -TOMORROW study-. EULAR 2015 abstract (AB0359).
Chen Lk., Liu LK., Assantachai P., et al. Sarcopenia in Asia: consensus report of the Asian Working Group for Sarcopenia. J Am Med Dir Assoc. 2014; 15: 95–101.
Disclosure of Interest None declared