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Researchers examined the link between LS and grip strength in RA, noting the importance of physical function as a key factor in managing aging populations.

In a recent study published online in Osteoporosis and Sarcopenia, researchers explored the association between grip strength and locomotive syndrome (LS) in patients with rheumatoid arthritis (RA), highlighting the importance of physical function as a key factor in managing aging populations.

According to the authors, as life expectancy rises globally, conditions like LS—characterized by reduced mobility due to musculoskeletal issues—pose significant challenges. LS is particularly relevant for patients with RA due to the systemic inflammation and joint damage associated with the disease, which can impair muscle function and increase LS risk.

“The purpose of this study was to verify grip strength as an evaluation tool for physical function and LS in [patients with] RA,” wrote Yasumori Sobue and colleagues.

Patients with RA often face muscle loss due to the catabolic effects of inflammation on skeletal muscle, contributing to an increased risk of LS. Given this, evaluating grip strength as a potential indicator of LS in RA patients becomes particularly valuable, according to the authors. Grip strength is a simple measure reflecting overall physical capacity and is linked to outcomes like sarcopenia (muscle loss) and LS progression. However, patients with RA often have inflammation in finger and wrist joints, which can reduce grip strength, making it crucial to adjust grip strength thresholds when assessing LS risk.

Grip Strength’s Correlation With LS

The study included 591 patients with RA, examining grip strength in relation to LS and adjusting for factors like age, disease duration, medication use, and joint inflammation. Results revealed that patients with LS tended to have lower grip strength, more advanced disease, and higher levels of joint inflammation than those without LS.

Male and female patients exhibited different grip strength thresholds for LS, with adjusted cut-off values for those with inflamed joints. Specifically, the study found that a grip strength of 24 kg for men and 17 kg for women indicated LS, with even lower values necessary for those with swollen joints.

Logistic regression analysis further confirmed the association between reduced grip strength and LS in both sexes, independent of joint inflammation. The study also found that grip strength could substitute for other disease activity measures, such as the Clinical Disease Activity Index (CDAI) and the Health Assessment Questionnaire Disability Index (HAQ-DI). This suggests that grip strength, alongside joint inflammation assessment, can effectively identify RA patients at risk of LS.

Enhancing Strength Mitigates LS Risk

The authors emphasized the multifactorial nature of muscle loss in RA, which includes age, disease progression, and inflammation. They also highlighted sex differences in RA progression and response to treatment, which might contribute to variations in grip strength. Given that patients with RA with finger and wrist joint inflammation typically experience worse disease outcomes, monitoring grip strength could help detect early signs of disease worsening and support interventions to prevent LS. Physical exercise and RA medication are recommended to enhance muscle strength and mitigate LS risk.

This study underscored the value of grip strength as a simple yet reliable tool for assessing LS in patients with RA, advocating for its use alongside other measures to optimize care for this vulnerable population.