Abstract / Summary
Background: Rheumatoid arthritis (RA) is a chronic autoimmune disorder with joint inflammation, muscle weakness, and mobility loss. The significance of muscle testing in RA is that muscle mass and strength directly influence survival, mobility, and quality of life.Objective: To assess the effectiveness of various commonly employed muscle strength tests in patients with RA compared with healthy controls. In addition, it sought to identify the muscle strength test that best discriminates functional status in a cross-sectional assessment.Materials and Methods: A cross-sectional comparative study included 82 female participants, comprising 41 RA patients and 41 healthy controls, all age-matched, conducted at the Baghdad Teaching Hospital between mid-December 2025 and March 2026. Muscle strength was evaluated using a handgrip dynamometer, the Five Times Sit-to-Stand Test (FTSST), a hanging spring scale, and manual muscle testing (MMT).Results: Patients with RA had significantly lower muscle strength and physical performance (P-value = 0.001) than the control group in all tests (the handheld dynamometer, the hanging spring scale, and the MMT), with a P-value of 0.001 for the FTSST. The Medical Research Council (MRC) scale of the MMT demonstrated the highest ability to distinguish between RA patients' and healthy individuals’ area under the curve (AUC) = 0.829, followed by handgrip strength measurement AUC = 0.731. The accuracy of the spring scale and FTSST was found to be moderate and low, respectively. Conclusion: RA has a major effect on muscle strength. The MRC scale was the most accurate assessment, and handgrip strength was acceptable. The spring scale was moderately effective, and the FTSST was low in effectiveness.