Patients with rheumatic and autoimmune diseases are often affected by sarcopenia. The syndrome, which is characterised by a loss of muscle strength and physical resilience, is the subject of a recent meta-analysis.1 Rheumatoid arthritis (RA) has been extensively researched in this regard. The autoimmune inflammatory response on which chronic joint inflammation is based could promote the development of sarcopenia.1 There are also interesting approaches from a therapeutic perspective: Some anti-rheumatic drugs such as tocilizumab not only alleviate the underlying disease, but also seem to curb sarcopenia. The situation is different with glucocorticoids, which are said to have a negative effect on muscle weakness.1
Sarcopenia is a common concomitant disease of RA, as many research studies have demonstrated. An analysis of 12 studies found a mean prevalence of 29.1%.1 Muscle weakness not only significantly reduces the quality of life of those affected. It also has clinical effects: lower bone density, increased risk of fractures, tendency to fall and cardiac events are possible consequences.1
Numerous factors that promote the development of sarcopenia in RA have been identified. These include:
A targeted treatment is not yet possible. However, according to current knowledge, anti-inflammatory therapy of RA also seems to counteract sarcopenia.1 This is because pro-inflammatory cytokines are not only involved in the development of RA, but are also associated with muscular function loss.1
Biological disease-modifying antirheumatic drugs (DMARDs) such as tocilizumab seem particularly promising. In a prospective research study, an increase in muscle mass was observed in patients with RA who were treated with the antibody for one year.1 A therapy for sarcopenia with tocilizumab is already recommended in some studies.1
Preventive approaches are also being discussed. For example, animal studies have shown that the adrenergic β2 receptor agonist formoterol, antioxidants or neuromuscular electrical stimulation can prevent sarcopenia.1
On the other hand, therapy with cortisone seems to be rather disadvantageous. Glucocorticoids have been associated with a clustered occurrence of sarcopenia in several studies. Already at a daily dose of ≥ 3.25 mg for one year, muscle weakness was observed to increase.1 Furthermore, a recent research study showed that after one year of treatment with cortisone, the prevalence for sarcopenia was 13.4%.1
Sarcopenia associated with rheumatic and autoimmune diseases is a much researched topic. Nevertheless, further study is needed to learn more about the role of chronic inflammatory processes as triggers for sarcopenia and to design therapeutic strategies for those affected. This could not only significantly improve the mobility of patients, but also their quality of life.
Reference:
1. An HJ, Tizaoui K, Terrazzino S, et al. Sarcopenia in Autoimmune and Rheumatic Diseases: A Comprehensive Review. Int J Mol Sci. 2020;21(16):5678. published 2020 Aug 7. doi:10.3390/ijms21165678