Systemic lupus erythematosus: a systematic review with meta-analysis on muscle strength, muscle mass, and physical function

To perform a systematic review with meta-analysis to verify muscle strength, muscle mass, and physical function of patients with systemic lupus erythematosus (SLE) and compare then with healthy individuals and patients with rheumatoid arthritis (RA). A systematic review with meta-analysis of observational studies published in English up to 2022 was performed using MEDLINE (via PubMed) and other relevant sources. Search strategies were based on pre-defined keywords and medical subject headings. The methodological quality of the studies was assessed using the Newcastle-Ottawa Scale. Mean difference (MD) or standardized mean difference (SMD) and 95% confidence intervals (CI) were combined using a random-effects model. Sensitivity analyses were performed when necessary. The significance level was set at p < 0.05. The systematic review included 19 studies and the meta-analysis included 11 studies. SLE patients appear to have less muscle strength assessed by handgrip than healthy controls (SLE = 21.74 kg; healthy controls = 29.34 kg; p < 0.05). SLE patients seem to have greater strength than patients with RA, but this difference was not statistically significant (RA = 17.24 kg; p = 0.210). However, in the sensitivity analysis, SLE group without deforming arthropathy showed higher muscle strength than the RA (p = 0.0001). SLE patients with deforming arthropathy have lower muscle strength compared to SLE patients without deforming arthropathy (p < 0.01). Muscle mass was similar in SLE patients compared to the RA group and healthy controls (p > 0.05). However, RA patients have a higher BMI than the two groups (p < 0.05). Patients with SLE have regular physical function. Muscle strength is affected in SLE patients. SLE patients with deforming arthropathy have less muscle strength than patients without deforming arthropathies.