Prognostic significance of low pre-transplant skeletal muscle mass on survival outcomes in patients undergoing hematopoietic stem cell transplantation.

Little is known about the prognostic significance of muscle loss for allogeneic hematopoietic stem cell transplantation (allo-HCT). We retrospectively analyzed consecutive patients who received allo-HCT from 2013 to 2015. All patients underwent computed tomography (CT) imaging and bioelectrical impedance analysis (BIA) within 30 days before allo-HCT. Skeletal muscle area (cm2) at the third lumbar vertebra level on CT imaging and skeletal muscle mass (kg) measured by BIA were normalized by height in meters squared (m2) to calculate the skeletal muscle area index (SMI) and skeletal muscle mass index (SMMI). SMI and SMMI were significantly correlated (r = 0.744; P < 0.001). The cumulative incidence of 1-year non-relapse mortality (NRM) was significantly higher in patients with low SMI than high SMI (17% versus 0%, respectively; P = 0.023). Overall survival was shorter in patients with low SMI than high SMI (56% versus 93%, respectively; P < 0.001). In univariate analysis, low SMI was associated with increased risk of NRM (HR 7.46; 95% CI 1.05-52.98; P = 0.044), and in multivariate analysis it was associated with higher overall mortality (HR 5.35; 95% CI 1.71-16.72; P = 0.004). These results suggest that low muscle mass is an independent predictor of mortality after allo-HCT.