Relationship between rheumatoid arthritis and locomotive syndrome: validation of the 25-question Geriatric Locomotive Function Scale in patients with rheumatoid arthritis

This study aimed to understand the clinical state of locomotive syndrome (LS) in patients with rheumatoid arthritis (RA) and to validate the use of the 25-question Geriatric Locomotive Function Scale (GLFS-25) in patients with RA and compare it side-by-side with the Health Assessment Questionnaire-Disability Index (HAQ-DI). Subjects were 159 patients with RA (female, 112 (70.4%); mean age, 66.2 ± 12.0 years) who consecutively visited Yokkaichi Municipal Hospital between June and August 2017. Mean disease duration was 11.4 ± 9.3 years, mean HAQ-DI score was 0.5 ± 0.7 points, and mean GLFS-25 score was 17.8 ± 19.1 points. The correlation between GLFS-25 and HAQ-DI was analyzed using Spearman's rank correlation coefficient. The cut-off point of GLFS-25 corresponding to HAQ-DI≤0.5, which represents functional remission in patients with RA, was calculated by ROC analysis. GLFS-25 and HAQ-DI were positively and strongly correlated (correlation coefficient=0.798). The cut-off point of GLFS-25 corresponding to HAQ-DI≤0.5 was 20 points (sensitivity, 81%; specificity, 90%). Thus, the cut-off point of GLFS-25 corresponding to functional remission is higher than that for developing LS (i.e., 16 points). Moreover, the proportion of patients with LS among those with HAQ-DI ≤0.5 was 17.9%. In conclusion, our findings suggest that some patients with RA in remission may have LS, as well as the need to consider appropriate interventions for such patients.