Effects of biologic and target synthetic disease-modifying anti-rheumatic drugs on sarcopenia in spondyloarthritis and rheumatoid arthritis: a systematic review and meta-analysis.

Sarcopenia is a syndrome defined by generalized and progressive loss of skeletal muscle mass, strength, and function. Besides affecting elderly population, it is actually common among inflammatory rheumatic diseases (IRD) patients. We performed a systematic literature review with a meta-analysis to investigate the influence of biologic and target synthetic disease-modifying anti-rheumatic drugs (bDMARDs/tsDMARDs) on sarcopenia in IRD. A systematic search has been performed on Pubmed, Scopus, and Web of science. Studies characteristics were collected. Assessment tools were body composition (total lean mass (TLM) and percentage, appendicular skeletal mass (ASM), fat-free mass and index (FFM and FFMI), skeletal mass index (SMI) and segmental lean mass (SLM)), and muscle strength and physical performance tests. Treatment effect defined the difference in change from baseline to the end of follow-up treatment was divided by the pooled SD of the difference. Twenty-two studies on 778 patients receiving bDMARDs/tsDMARDs and 157 controls were reviewed. They investigated rheumatoid arthritis (RA) (N = 14), spondyloarthritis (SpA) (N = 6), psoriatic arthritis (N = 1), and both RA and SpA (N = 1). tsDMARDs were used in one study with no effect on sarcopenia. Ten studies demonstrated that bDMARDs increased significantly muscle measures in 347 patients (44.6%) with a significant increase in TLM (6/15 studies; 57.4%), FFMI (4/6 studies; 59.9%), ASM (2/5 studies; 17.6%), SMI (2/5 studies; 18.1%), and SLM (2/2 studies; 3.6%). bDMARDs showed also a positive effect on handgrip strength in 1/3 of studies (45.2%) and on physical performance in 1/2 of studies (61%). In 1/5 of comparative studies, IRD patients on bDMARDs showed significantly higher increase of TLM in comparison to controls naïve bDMARDs. Regarding diagnosis, positive effect of bDMARDs was seen in 67.4% in SpA versus 49.3% in RA, with a significant increase of TLM, ASM and FFMI in 59.4%, 100%, and 65.2% in SpA versus 54.9%, 24.1%, and 54.8% in RA, respectively. Meta-analysis assessed the effect of bDMARD on TLM in 10 studies. There was no statistically significant difference [SMD - 0.10 (95% Confidence Interval - 0.26 - 0.06; tau 2  = 0). Heterogeneity across studies was null, and the 95% confidence interval (index of precision) was equal to the 95% predictive interval. The first systematic literature review showed that bDMARDs have a significant improve effect in nearly half of RA and SpA patients on muscle mass and muscle strength, assessed separately. However, the meta-analysis concluded that bDMARDs have no significant effect on TLM.