Impact of excessive body fat mass on mortality after lung transplantation

AbstractObjective To investigate whether changes in body composition up to 2 years after lung transplantation are associated with long-term prognosis. Methods We retrospectively investigated changes in body composition and their association with mortality using a Cox proportional hazards regression model in patients who underwent lung transplantation at Kyoto University between 2013 and 2018. Body components, such as body mass index (BMI), fat-free mass index (FFMI), and body fat mass index (FMI) were obtained at discharge, 6 months, 1 year, and 2 years post-transplantation. Results The analysis included 71 patients (39 males, mean age 48.0 years). The BMI, FFMI, and FMI increased significantly until 1 year post-transplantation. The respective distributions of each classification (low, standard, and high) for each body component at 1 year post-transplantation were as follows: BMI, 37.9%, 60.6%, and 1.5%; FFMI, 71.2%, 28.8%, and 0%; and FMI, 33.3%, 36.4%, and 30.3%. The FMI at 1 year post-transplantation was an independent factor, and the group with a high FMI at 1 year post-transplantation had significantly lower survival (hazard ratio, 5.370; 95% confidence interval, 1.396-20.660; P = .014). Conclusions After lung transplantation, the patients had increased BMI, FFMI, and FMI. The FMI increased above the reference values in an increasing number of patients, and a high FMI at 1 year post-transplantation was associated with a poor prognosis.