Thoracic muscle cross-sectional area is associated with hospital length of stay post lung transplantation: a retrospective cohort study

Low muscle mass is common in lung transplant (LTx) candidates; however, the clinical implications have not been well described. The study aims were to compare skeletal muscle mass in LTx candidates with controls using thoracic muscle cross-sectional area (CSA) from computed tomography and assess the association with pre- and post-transplant clinical outcomes. This was a retrospective, single-center cohort study of 527 LTx candidates [median age: 55 IQR (42-62) years; 54% male]. Thoracic muscle CSA was compared to an age-and sex-matched control group. Associations between muscle CSA and pre-transplant six-minute walk distance (6MWD), health-related quality of life (HRQL), delisting/mortality, and post-transplant hospital outcomes and one-year mortality were evaluated using multivariable regression analysis. Muscle CSA for LTx candidates was about 10% lower than controls (n = 38). Muscle CSA was associated with pre-transplant 6MWD, but not HRQL, delisting or pre-or post-transplant mortality. Muscle CSA (per 10 cm 2 difference) was associated with shorter hospital stay [0.7 median days 95% CI (0.2-1.3)], independent of 6MWD. In conclusion, thoracic muscle CSA is a simple, readily available estimate of skeletal muscle mass predictive of hospital length of stay, but further study is needed to evaluate the relative contribution of muscle mass versus functional deficits in LTx candidates.