Treatment Failure with combined csDMARDs increases the risk of Low Muscle Mass in women with Rheumatoid Arthritis: a cross-sectional study

Abstract

Background Low muscle mass (myopenia) is frequent in rheumatoid arthritis (RA) patients with a long-disease duration. Although, the use of combined therapy with conventional synthetic DMARDs (csDMARDs) is one of the main strategies observed in these patients; there is a lack of information if the failure to these therapies increases the risk of myopenia. Objective: To evaluate whether the treatment failure to combined therapy with conventional synthetic DMARDs is an independent risk factor for low skeletal muscle mass in women with RA. Methods This cross-sectional study compared 277 women with RA (cases) and 237 women from non-rheumatic population (controls). In RA patients, we assessed clinical, epidemiological, and therapeutic variables (identifying treatment failure to combined therapy with csDMARDs. The skeletal muscle index (SMI) was estimated by DXA. Low skeletal muscle mass was defined as SMI<5.45 kg/m2. Multivariate logistic regression analyses were used to a) evaluate whether RA is an independent risk factor of myopenia in comparison with non-rheumatic population and b) identify if treatment failure with csDMARDs is an independent risk factor of myopenia in RA. Results RA patients had a higher prevalence of low skeletal muscle mass than controls (27.8% vs. 15.6%, p=0.001). After adjusting for other factors, RA patients had higher risk of low skeletal muscle mass than controls (OR: 2.7, 95%CI:1.7 to 4.5). Risk factors of low muscle mass in RA patients; were: menopause (OR: 2.3, 95%CI: 1.2 to 4.6, p=0.02) and a failure to combined therapy with csDMARDs (OR: 2.4, 95%CI: 1.10 to 5.81, p=0.03). Conclusions Rheumatoid arthritis is associated with an increased risk of myopenia. Treatment Failure with conventional-synthetic DMARDs constitutes a strong risk factor for deteriorated skeletal muscle mass.