Clinical application of equation predicting appendicular skeletal muscle mass in patients with esophageal cancer: A retrospective analysis of a cross-sectional study.

Background: Dual-energy X-ray absorptiometry and bioelectrical impedance analysis (BIA) are used to measure appendicular skeletal muscle mass (ASM). However, these two methods can be contraindicated in some cases. Therefore, equations have been developed to predict ASM using anthropometric parameters, which is a less expensive and more feasible approach. This study evaluated the correlation between the predicted ASM calculated using a previously reported prediction equation and the actual ASM measured using BIA. Moreover, we determined their degree of agreement in diagnosing sarcopenia in patients with esophageal cancer.

Materials and methods: From a previous study involving 119 patients with esophageal cancer, perioperative anthropometric parameters (height, weight, waist and circumference), and grip strength (GS) were obtained to calculate ASM in Japanese participants using a previously reported prediction equation (Furushima equation). The validity of the predicted ASM was evaluated by comparing it with the actual ASM measured using BIA. Moreover, we determined the ability of the predicted ASM and GS results to diagnose sarcopenia in patients with esophageal cancer before and 4 weeks after surgery.

Results: A moderate agreement (before surgery: Lin concordance correlation coefficient [CCC] = 0.88; 4 weeks after surgery: Lin CCC = 0.89) was observed between the predicted ASM and the actual ASM. Furthermore, the predicted and measured ASM values showed substantial agreement in diagnosing sarcopenia (before surgery: κ statistics = 0.61; 4 weeks after surgery: κ statistic = 0.65).

Conclusion: The equation developed for predicting ASM in Japanese participants can be applied to patients with esophageal cancer.