Donor-Recipient Body Mass Index Matching in Lung Transplantation

Abstract

Purpose Donor-recipient size matching, in terms of height, total lung capacity and chest x-ray measurements, has been studied and is known to affect outcomes. Less is known about the impact of BMI matching which could have equally important implications on outcomes. We analyzed the Scientific Registry of Transplant Recipients (SRTR) database to determine the effects of BMI-matching on patient survival and graft function after lung transplant. Methods We evaluated a national cohort of patients from the SRTR database who underwent single or double lung Tx between 2006-17. Donor and recipient BMI were categorized using the World Health Organization classification: underweight (BMI 14.0-18.49); normal, (18.5-24.99); overweight (25.00-29.99); obese (≥30.00). In addition, donor and recipient BMI categories were used to stratify patients based on donor-recipient BMI matching: same category; donor BMI in a higher category than the recipient; recipient BMI in a higher category than the donor. The association between donor BMI, recipient BMI, as well as donor-recipient BMI similarity and overall risk of death or risk of graft loss were separately evaluated using multivariable Cox regression. Results Among 20,404 patients, median donor BMI was 25.1 [IQR 22.3-28.7] and median recipient BMI was 25.4 [IQR 21.6-28.7]. For donors, 3.5% were underweight, 44.6% were normal weight, 32.7% were overweight, and 19.2% were obese. For recipients, these were 8.5%, 38.8%, 37.2%, and 15.6%, respectively. Donor BMI was not associated with overall risk of death or risk of graft loss. By comparison, relative to normal weight recipients, underweight recipients had a 42% higher risk of death (Hazard Ratio 1.42 [95% CI 1.02-2.00]). Relative to patients receiving organs from a donor in a similar BMI category, donor-recipient differences in BMI category were neither associated with risk of death nor graft loss. Conclusion Consistent with prior reports, recipient BMI was an important factor in lung transplant outcomes, but donor-recipient BMI matching, or lack of, did not have an effect. Neither donor BMI nor donor-recipient size matching based on BMI are associated with improved Tx outcomes.