We read with interest the article by Krell et al., who highlight the relationships between sarcopenia, posttransplant infectious complications, and mortality in adults undergoing liver transplantation. We were surprised that they define sarcopenia by the calculation of the cross-sectional area of both psoas muscles at the level of the fourth lumbar vertebra via computed tomography scans.
A definition for sarcopenia was first proposed by Irwin Rosenberg in 1989, and through a consensus statement of the European Working Group on Sarcopenia in Older People, a widely accepted definition, suitable for use in research and clinical practice, was generated. According to the European Working Group on Sarcopenia in Older People, sarcopenia is the presence of both low muscle mass and low muscle function (strength or performance), whereas low muscle mass without muscle function loss is defined as presarcopenia. In this work, Krell et al. use the total psoas area to predict low muscle mass. To the best of our knowledge, there is no study on the validity of the total psoas area as a predictor of the total body mass. Krell et al. refer to a study by Englesbe et al. on the validity of the total psoas area calculation; however, that study was not designed to generate a new tool for predicting the total body mass. Moreover, Krell et al. do not report results for the muscle function of subjects, so presarcopenic and sarcopenic subjects might have been easily misclassified. Due to these limitations, the assignment of sarcopenia in this work seems to be suboptimal.
Umut Safer, M.D.1Vildan Binay Safer, M.D.2
1Department of Geriatrics Gulhane School of Medicine Ankara, Turkey
2Department of Physical Medicine and Rehabilitation Ankara Physical Medicine and Rehabilitation Research and Training Hospital Ankara, Turkey