Influence of Donor Bmi on Single and Double Lung Transplant Survival

Abstract

Several studies have demonstrated that recipients who are underweight or obese were associated with increased in mortality after lung transplantation. However, to our knowledge, there is no study on the effect of donor body mass index (BMI) on post-transplant survival outcome. This study was conducted to understand how donor obesity, measured by donor BMI, impacts 1-year survival for lung transplant recipients. METHODS: The UNOS Standard Transplant and Analysis database was queried for patients >18 years old who received either single or double lung transplant between year 2005-2018. Donor BMI was categorized into underweight, normal weight, overweight and grades of obesity (underweight ¼ BMI <18.49, normal ¼ BMI 18.50-24.99, overweight ¼ BMI 25.00-29.99, obesity class I ¼ BMI 30.00-34.99, obesity class II-III ¼ BMI >35.00). Adjusted recipient variables were age, race, sex, BMI, smoking history, chronic steroid use, diabetes mellitus (DM) history, creatinine level at the time of transplant, ischemic time, lung allocation score (LAS) and primary lung disease (COPD, pulmonary fibrosis, cystic fibrosis and others). Adjusted donor variables were age, race, sex, alcohol history, smoking history, hypertension history and DM history. Cox regression was performed to determine adjusted hazard ratios for 1-year survival. RESULTS: A total of 15,982 patients were included in final analysis. Median recipient age was 59 and 40.4% were female. Average donor BMI was 25.9 and 45.4% were classified as normal weight. In adjusted models, improved survival was noted for patients who received lung transplantation from recipients in obesity class I (HR 0.867, 95% CI: 0.772-0.975) and obesity class II-III (HR 0.804, 95% CI: 0.688-0.941) versus recipients of normal weight. There was no statistically significant difference between underweight or overweight recipients versus those of normal weight. In adjusted recipient variables, poorer survival was noted for increased recipient age, recipient BMI categories of underweight, class I and class II-III, chronic steroid use, LAS score >80, ischemic time >6 hours, higher creatinine level (>1.5) and other primary lung disease group. In adjusted donor variables, poorer survival was noted for older donor age, male sex and presence of DM history. CONCLUSIONS: Increased donor BMI appears to confer 1-year survival benefit for lung transplant recipients. A 15% and 20% reduction in mortality were respectively seen among recipients who received transplants from class I and Class II-III obese donors. CLINICAL IMPLICATIONS: While BMI is an imperfect measurement of obesity, underlying mechanisms such as chronic adaptation to hypoxic conditions in obese population may explain an increased survival and impact donor lung selection. Further investigation is needed to further validate and understand this relationship.

Risk factors and outcomes of BK viremia among deceased donor kidney transplant recipients based on donor characteristics

“…In fact, a mortality benefit has been demonstrated in both lung and heart transplantation, without a well-defined mechanism to explain this finding. 35,36 While morbid obesity is a relative contraindication to living donor kidney donation due to associated risks to the donor, when pursued it does not appear to negatively affect recipient graft outcomes. 37 In the deceased donor population, donor obesity has been associated with delayed graft function; however, no difference in 1-year graft outcomes.…”