Reply.

Abstract

Potential conflict of interest: Nothing to report. TO THE EDITOR: We appreciate the valuable comments provided by Xue et al. on our submitted article. We assessed the association between the perioperative decrease in the psoas muscle index (PMI) and patient survival after living donor liver transplantation (LDLT). Below are our responses to the issues that they raised. First, we agree with the need to pay special attention to preoperative hematocrit and albumin levels when the association between core muscle mass and patient survival is assessed. Anemia is associated with a decrease in muscle mass and strength, and hypoalbuminemia is considered a risk factor for loss of skeletal muscle mass.1 Preoperative anemia and hypoalbuminemia are highly prevalent in patients with chronic liver disease, and previous reports have revealed that low preoperative hematocrit and albumin levels are associated with increased mortality after liver transplantation (LT).2 However, in this study, we focused on the association between “perioperative changes in core muscle mass” and patient survival. We provide additional information from previous reports in which the association between preoperative sarcopenia and patient survival after LT was evaluated.4 Hematocrit and albumin levels were not significantly different preoperatively between the low‐loss (PMI ≥ −11.7%) and high‐loss (PMI < −11.7%) groups in the study. We must assess changes in various factors, including hematocrit and albumin levels, as Xue et al. suggested, to determine which factors caused a decrease in the PMI. This important question should definitely be answered in subsequent studies. Second, it is quite true that all known risk factors affecting the measured outcome must be considered by the model to obtain the true inferences of a multivariate regression analysis for the adjusted hazard ratio. We observed that dialysis, early allograft dysfunction, all‐cause reoperation, and infection were postoperative complications associated with patient survival in a univariate Cox regression analysis. We also compared other major complications, including acute cellular rejection, biliary problems, hepatic vessel thrombosis, and de novo cancer between the low‐loss and high‐loss groups, which were considered to affect patient outcome. These complications were comparable between the 2 groups during the follow‐up period and were not significant with overall patient mortality in a univariate Cox regression analysis and are not included in Table 4. However, these factors are still important and major concerns for patients who undergo LT because previous studies have reported an association between poor postoperative outcomes and acute rejection, biliary and hepatic vascular problems, and cancer recurrence. In addition, as Xue et al. indicated, postoperative development of gastrointestinal bleeding, pulmonary complications, sepsis, and multiple‐organ failure are considered independent factors for increased mortality after LT, which we did not provide in the manuscript.5 LT inevitably includes extensive surgery and postoperative intensive care, which could induce accelerated sarcopenic changes in vulnerable patients with end‐stage liver disease. Further studies are required to validate whether these changes are modifiable and to determine the factors related to perioperative sarcopenic changes after LT.