Verification of grip strength as an evaluation tool for locomotive syndrome in rheumatoid arthritis

Objectives

Locomotive syndrome (LS) leads to reduced physical function and a high risk of becoming bedridden. Grip strength serves as an indicator of upper limb and overall physical function. Rheumatoid arthritis (RA) patients with reduced grip strength frequently show finger and wrist joint inflammation. The purpose of this study was to verify grip strength as an evaluation tool for physical function and LS in RA patients.

Methods

As part of an ongoing multicenter observational study, 591 consecutive RA patients whose background information was available, including data for the 25-question Geriatric Locomotive Function Scale (GLFS-25) and grip strength, were examined. LS was defined as a GLFS-25 score ≥ 16 points. Finger and wrist joint inflammation were defined as tender or swollen joints.

Results

Among the 591 patients, 244 (41.3%) patients had LS, and 167 (28.3%) were male. Receiver operating characteristic curve analysis yielded cut-off values of grip strength for LS of 24 kg (specificity 72.2%; sensitivity 62.7%) for males and 17 kg (specificity 65.7%; sensitivity 67.6%) for females. Multivariable logistic regression analysis revealed a significant association of grip strength with LS, even after adjusting for finger and wrist joint inflammation.

Conclusions

LS was significantly associated with grip strength, even after adjusting for the presence of finger and wrist joint inflammation. We recommend adopting grip strength measurement as a screening tool for evaluating LS and guiding interventions.