Muscle Strength Comparison in Immune-Mediated Rheumatic Disease vs Healthy Adults: A Meta-Analysis

Patients with immune-mediated rheumatic diseases (IMRDs) often exhibit reduced muscle strength. Therefore, this review aimed to evaluate muscle strength in patients with IMRDs compared with healthy control and to summarize the relationship between low muscle strength and clinical features in patients with IMRDs.

Systematic review with meta-analysis of case-control studies.

Patients with IMRDs.

A comprehensive search was conducted in the Embase, MEDLINE, Web of Science, and Cochrane databases to identify relevant studies published up to November 2023 on rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis, and spondyloarthritis. Meta-analysis was performed using a random-effects model to determine the mean difference (MD) in muscle strength between patients with IMRDs and an age- and sex-matched healthy control group.

We identified 11,692 studies, and 760 studies were selected for screening. Ultimately, 26 studies met the inclusion criteria, composed of 2661 individuals, mostly women. The IMRDs women group had lower handgrip muscle strength (MD, -9.53; 95% CI, -11.78 to -7.28 kg) than the healthy control group, whereas the handgrip strength men groups did not differ significantly from that of the healthy control group. Similar trend was observed in lower limb muscle strength for the IMRDs women group than the healthy control group (MD, -63.10; 95% CI, -94.18 to -32.01 Nm). Four studies examined muscle strength and clinical features in rheumatoid arthritis: one associated it with age and disease activity, 2 associated it with disease duration, and 3 associated it with physical function. In systemic lupus erythematosus, only 2 studies associated low muscle strength with age, disease activity, and fatigue. No associations were found in spondyloarthritis, and none were found in systemic sclerosis.

Patients with IMRD exhibit lower muscle strength than healthy counterparts, with low strength moderately associated with longer disease duration, worsening disease activity, and decline in physical function. Targeted interventions are crucial for preventing and managing muscle weakness in IMRDs.