Myosteatosis is associated with poor survival after kidney transplantation: a large retrospective cohort validation

We aim to establish diagnostic thresholds of sarcopenia and myosteatosis based on CT measurements, and to validate their prognostic value in a large cohort of kidney transplant recipients. Local healthy population with abdominal CT between 2010 and 2022, and patients underwent kidney transplantation between 2015 and 2019 at our center were retrospectively included. The skeletal muscle index and muscle attenuation of abdominal muscles were calculated based on CT image at the middle of the third lumbar vertebra. Primary endpoints included all-cause mortality and death censored allograft survival. Age- and sex-specific thresholds for sarcopenia and myosteatosis were established based on 1598 healthy local population. The final patient cohort consisted of 992 kidney transplant recipients (median age 34 years, interquartile range 28–44 years; 694 males), including 33 (3.3%) with sarcopenia and 95 (9.5%) with myosteatosis. Multivariate analysis revealed myosteatosis (adjusted hazard ratio = 3.08, p = 0.022) was an independent baseline risk factor of mortality after adjusting for age, the history of cancer, and the history of cardiovascular event. Multivariate analysis found preemptive transplantation (adjusted hazard ratio = 0.36, p = 0.037) was an independent protective factor of allograft loss. No difference was found in the prognosis between kidney transplant recipients with and without sarcopenia. Myosteatosis was an independent risk factor of mortality after kidney transplantation, but sarcopenia was not. Neither sarcopenia nor myosteatosis was associated with graft loss.