BMI Change and Outcomes in Lung Transplant Recipients

Abstract

Purpose Lung transplantation is a lifesaving therapy in patients with advanced lung disease. A body mass index (BMI) >30 is associated with worse outcomes after lung transplantation. Therefore, a BMI above 30 is considered a relative contraindication for lung transplantation in many centers. However, it is not clear how BMI changes after lung transplantation affects outcomes. Here we investigated how BMI changes after lung transplantation affect outcomes of lung transplant recipients. Methods We retrospectively assessed BMI and several post-transplant outcomes in 118 consecutive lung transplant recipients. The data was analyzed using R 4.0.2 (The R Foundation for Statistical Computing http://www.R-project.org). Packages Performance Analytics and ggplot2 were used in addition to core R. We evaluated impact of BMI change on mortality by running a Wilcoxon Sum-Rank test. We also did regression analysis controlling for impact of age, gender, race, type of lung transplant and length of stay. Results We evaluated 118 lung transplant recipients, 58 of whom were female. The average age was 56.06 years. Using traditional BMI categories, 7% of patients were underweight, 47% normal weight, 37% overweight, and 9% obese. Decrease in BMI of 2 or more points at 6 months after lung transplant was associated with increase mortality with odds ratio of death 5.13 and p=0.014. This effect was preserved when controlled for age, length of stay, gender, race, and type of transplant (p=0.02534). Interestingly, longer length of stay (LOS) was also associated with increased mortality independent from change in BMI, age, gender, race and type of transplant (p=0.00316). Conclusion A rather large proportion of lung transplant candidates are overweight by BMI criteria. A higher BMI was associated with a longer LOS after transplant and longer length of stay was associated with increased mortality. This effect was independent from change in age, gender, race and type of lung transplant. Patients who lost weight resulting in >2 points decrease in BMI at 6 months post-transplant also had increased mortality. This effect was independent from age, gender, race, length of stay and type of lung transplant. Larger studies are needed to confirm these findings and better understand the impact of weight change on outcomes after lung transplant. Lung transplantation is a lifesaving therapy in patients with advanced lung disease. A body mass index (BMI) >30 is associated with worse outcomes after lung transplantation. Therefore, a BMI above 30 is considered a relative contraindication for lung transplantation in many centers. However, it is not clear how BMI changes after lung transplantation affects outcomes. Here we investigated how BMI changes after lung transplantation affect outcomes of lung transplant recipients. We retrospectively assessed BMI and several post-transplant outcomes in 118 consecutive lung transplant recipients. The data was analyzed using R 4.0.2 (The R Foundation for Statistical Computing http://www.R-project.org). Packages Performance Analytics and ggplot2 were used in addition to core R. We evaluated impact of BMI change on mortality by running a Wilcoxon Sum-Rank test. We also did regression analysis controlling for impact of age, gender, race, type of lung transplant and length of stay. We evaluated 118 lung transplant recipients, 58 of whom were female. The average age was 56.06 years. Using traditional BMI categories, 7% of patients were underweight, 47% normal weight, 37% overweight, and 9% obese. Decrease in BMI of 2 or more points at 6 months after lung transplant was associated with increase mortality with odds ratio of death 5.13 and p=0.014. This effect was preserved when controlled for age, length of stay, gender, race, and type of transplant (p=0.02534). Interestingly, longer length of stay (LOS) was also associated with increased mortality independent from change in BMI, age, gender, race and type of transplant (p=0.00316). A rather large proportion of lung transplant candidates are overweight by BMI criteria. A higher BMI was associated with a longer LOS after transplant and longer length of stay was associated with increased mortality. This effect was independent from change in age, gender, race and type of lung transplant. Patients who lost weight resulting in >2 points decrease in BMI at 6 months post-transplant also had increased mortality. This effect was independent from age, gender, race, length of stay and type of lung transplant. Larger studies are needed to confirm these findings and better understand the impact of weight change on outcomes after lung transplant.