Association between adductor pollicis muscle thickness and low skeletal muscle mass index in community-dwelling older women undergoing outpatient rehabilitation.

OBJECTIVE

The performance of sarcopenia diagnosis using adductor pollicis muscle thickness (APMT) has been reported. However, the relationship between APMT and low skeletal muscle mass index (SMI) is unclear. The purpose of this study is to investigate the relationship between APMT and low SMI and APMT performance to diagnose low SMI in community-dwelling older women undergoing outpatient rehabilitation.

METHODS

This study included 65 older women (mean age: 86.4 years). Subjects were received outpatient rehabilitation one to three times a week. The main outcomes were low SMI as diagnosed using the Asian working group for sarcopenia 2019 and APMT. Logistic regression analysis was performed with low SMI as the dependent variable, APMT, and propensity score calculated using age, sex, number of medications, and updated Charlson comorbidity index as the independent variable. A receiver operating characteristic (ROC) curve of APMT for low SMI was created. A cut-off value was calculated using the Youden index.

RESULTS

Among the 65 subjects, 45 (69.2 %) had low SMI. The results of the logistic regression analysis showed a significant association between APMT and low SMI (odds ratio: 0.482 {95 % confidence interval [CI]: 0.313-0.744}). The cut-off value of APMT calculated from the ROC curve was 13 mm. The sensitivity and specificity of this cut-off value were 0.800 (95 % CI: 0.654-0.904) (36 out of 45 subjects) and 0.850 (95 % CI: 0.621-0.968) (17 out of 20 subjects), respectively. The positive predictive value, negative predictive value, and area under the curve were 0.923 (95 % CI: 0.791-0.984), 0.654 (95 % CI: 0.443-0.828), and 0.843 (95 % CI: 0.731-0.955), respectively. The APMT cut-off value of 13 mm is good to identify low SMI.

CONCLUSIONS

The results of this study show that APMT is associated with low SMI. Furthermore, the cut-off value of APMT for diagnosing low SMI was 13 mm. The APMT cut-off value of 13 mm is good to identify low SMI. Our findings indicate that measuring APMT is useful for diagnosing low SMI in community-dwelling older women undergoing outpatient rehabilitation.