Answer to the Letter to the Editor concerning “The association of back muscle strength and sarcopenia-related parameters in the patients with spinal disorders” by Toyoda H, et al. (Eur Spine J; doi.org/10.1007/s00586-018-5858-8)

[摘要] Thank you very much for commenting on the methodology used in our recent study. We were surprised by the large number of comments regarding the accurate defnition of sarcopenia and the gold standard methods for muscle mass evaluation [1–8]. As you said in your Letter to the Editor, researchers should minimize the variations in water distribution in the body when using bioelectrical impedance analysis (BIA) for muscle mass evaluation. We have data regarding the comorbidities of the included participants; however, we have no detailed data regarding the stomach contents and residual urine volume before BIA. All participants included in our study were ambulatory and had no severe comorbidities, dehydration and/or edema requiring medical treatment. Future, large-scale, prospective studies should include a comprehensive evaluation of the capacity of hydrated tissues throughout the body to help obtain more accurate results about the relationship between sarcopenia and spinal disorders.