Comparison of sarcopenia diagnosis defined by low muscle mass measured by bioelectrical impedance analysis (BIA) or computed tomography (CT) in combination with low muscle strength in older adults with cancer.

Abstract

e23252 Background: International guidelines establish cutoff values for low muscle mass, as measured by DXA or BIA, as a component of sarcopenia definition. The use of CT to measure skeletal muscle area at the L3 level has recently emerged as an alternative method for assessing muscle mass. For the first time, the Japan Society of Hepatology (JSH) guidelines for sarcopenia introduced cutoff values for CT-based low muscle mass [Hepatol Res. 2016 Sep;46(10):951-63]. The JSH defines sarcopenia as low muscle mass measured by CT or BIA, combined with low muscle strength measured by hand grip strength (HGS). We aimed to externally validate the JSH definition in the oncology setting. Methods: 630 consecutive older adults with cancer who underwent BIA as part of a comprehensive geriatric assessment (CGA) at a geriatric oncology service in Japan between December 2021 and September 2024 and had a routine CT image at the L3 vertebra level within 30 days of the BIA were included. Reliability was assessed by the agreement between sarcopenia diagnoses using the CT-based (< 42 cm 2 /m 2 for men, < 38 cm 2 /m 2 for women) and BIA-based (< 7.0 kg/m 2 for men, < 5.7 kg/m 2 for women) criteria for low muscle mass, combined with low HGS (< 28 kg for men, < 18 kg for women). The agreement between the two methods was analyzed using cross-tabulation, Cohen's kappa and Gwet's AC1. Construct validity was evaluated by comparing the physical performance tested during CGA between patients with and without sarcopenia. Results: Median age was 80 years, 63% were male, and 71% had gastrointestinal cancer. Using the CT- and BIA-based diagnostic criteria, sarcopenia was diagnosed in 189 (30%) and 177 (28%) patients, respectively. Overall percent agreement, kappa and AC1 between the two methods were 89% (95% CI 86%–91%), 0.73 (95% CI 0.67–0.79) and 0.81 (95% CI 0.77–0.86). Setting the BIA plus HGS definition as a non-reference standard, positive and negative percent agreement of the CT plus HGS definition were 84% (95% CI 77%–89%) and 91% (95% CI 88%–93%). Compared to the group without sarcopenia, those with sarcopenia by either definition had lower physical performance (Table). Conclusions: Our findings provide the first evidence to support the reliability and construct validity of the JSH sarcopenia definition in older Japanese adults with cancer. Further research is warranted to validate these findings across diverse populations. 　CT plus HGS definition 　BIA plus HGS definition Sarcopenia (n=189) No sarcopenia (n=441) p value Sarcopenia (n=177) No sarcopenia (n=453) p value 4-m gait speed (m/s) 0.73 0.85 <.001 0.71 0.85 <.001 Five Times Sit-to-Stand (sec) 17.4 13.2 <.001 18.4 12.9 <.001 SPPB score (range 0-12) 8.0 9.7 <.001 7.6 9.8 <.001 Timed Up and Go (sec) 19.4 15.2 <.001 20.9 14.8 <.001 PF-10 score (range 0-100) 52.8 70.9 <.001 51.4 70.9 <.001