Sarcopenia is associated with increased wait-list mortality, but a standard definition is lacking. In this retrospective study, we sought to determine the optimal definition of sarcopenia in end-stage liver disease (ESLD) patients awaiting liver transplantation (LT). Included were 396 patients newly listed for LT in 2012 at 5 North American transplant centers. All computed tomography scans were read by 2 individuals with interobserver correlation of 98%. Using image analysis software, the total cross-sectional area (cm2) of abdominal skeletal muscle at the third lumbar vertebra was measured. The skeletal muscle index (SMI), which normalizes muscle area to patient height, was then calculated. The primary outcome was wait-list mortality, defined as death on the waiting list or removal from the waiting list for reasons of clinical deterioration. Sex-specific potential cutoff values to define sarcopenia were determined with a grid search guided by log-rank test statistics. Optimal search methods identified potential cutoffs to detect survival differences between groups. The overall median SMI was 47.6 cm2/m2: 50.0 in men and 42.0 in women. At a median of 8.8 months follow-up, mortality was 25% in men and 36% in women. Patients who died had lower SMI than those who survived (45.6 versus 48.5 cm2/m2; P < 0.001), and SMI was associated with wait-list mortality (hazard ratio, 0.95; P < 0.001). Optimal search method yielded SMI cutoffs of 50 cm2/m2 for men and 39 cm2/m2 for women; these cutoff values best combined statistical significance with a sufficient number of events to detect survival differences between groups. In conclusion, we recommend that an SMI < 50 cm2/m2 for men and < 39 cm2/m2 for women be used to define sarcopenia in patients with ESLD awaiting LT. Liver Transplantation 23 625–633 2017 AASLD.
ASJC Scopus subject areas