摘要Background:In patients with different medical conditions,sarcopenia is associated with adverse clinical outcomes,so screening for sarcopenia is a crucial aspect of clinical practice.The study used computed tomography(CT)imaging and bioelectrical impedance analysis(BIA)to assess whether skeletal muscle mass loss was associated with poor clinical outcomes in patients undergoing allogeneic hematopoietic stem cell transplantation(allo-HSCT).Methods:Patients who received allo-HSCT in The First Affiliated Hospital of Soochow University from October 2018 to December 2020 were enrolled into this study.The fat-free muscle mass(FFMI)was estimated using BIA,while the pectoralis muscle area index(PMI)was analyzed via CT scans at T4.These were used to compute a skeletal muscle index.Results:In total,158 patients with hematologic malignancies were enrolled.Individuals with a reduced PMI or FFMI before transplantation had a greater likelihood of inferior overall survival compared to those with normal values(P=0.025 and P=0.030,respectively).Multivariable regression indicated that pre-transplant sarcopenia,defined by these indices,constituted an independent predictor for overall mortality[hazard ratio(HR):2.04,95%confidence interval(CI):1.06-3.95,P=0.034;HR:2.21,95%CI:1.13-4.31,P=0.020].Patients with a lower FFMI had a higher nonrelapse mortality(NRM)at 2 years.The competing risks model suggested that the odds ratio for patients with a low FFMI at risk for NRM was 2.86 compared with normal groups(95%CI:1.23-6.62).Conclusions:In patients undergoing HSCT,low scores on the PMI and FFMI indicate poor survival outcomes.