A. M. Lang1, S. Kamepalli1, A. Rana2 1Baylor College Of Medicine, Department Of Student Affairs, Houston, TX, USA 2Baylor College Of Medicine, Division Of Abdominal Transplantation, Houston, TX, USA
Introduction:
It is well established that a higher body mass index (BMI) in transplant donors and recipients is associated with adverse post-transplant outcomes. However, the thresholds at which BMI significantly affects survival following transplantation have not been systemically investigated. Determining the points at which post-transplant survival are appreciably influenced by donor or recipient BMI can allow for a more accurate prediction of transplant survival outcomes.
Methods:
Using de-identified data from the United Network for Organ Sharing (UNOS) database, 326,005 transplant recipients (0-73 years of age) and 326,005 donors (0-74 years of age) from September 1987 to July 2021 were retrospectively analyzed using Stata® 17.0. BMI groups with less than 100 recipients or donors were excluded from this analysis. The Joinpoint Regression Program (Version 4.9.1.0) was used to determine statistically significant BMI “joinpoints” for allograft donors and recipients. Poisson regression was used to evaluate mean survival outcomes, and a permutation model selection method was utilized in the analysis to determine the optimal number of “joinpoints”.
Results:
Among the donors, there was 1 significant “joinpoint'' that indicated differences in mean survival by BMI: a BMI of 33 (Confidence Interval [CI]: 30-37). Mean survival declined significantly less after the “joinpoint''. The estimated percent change in survival changed from -2.44 years per BMI unit in patients with a BMI<33 to -0.62 years per BMI unit in patients with a BMI>33. Among the recipients, there were 3 significant “joinpoints” that indicated differences in mean survival by BMI: a BMI of 19 (CI: 30-37), a BMI of 35 (CI: 26-42), and a BMI of 46 (CI: 44-46). Mean survival declined significantly between each “joinpoint,” with the steepest dropoff after a BMI of 46. The estimated percent change in survival changed from -4.77 years per BMI unit in patients with a BMI<19 to -1.25 years per BMI unit in patients with a BMI between 19 and 35. Mean survival declined most dramatically in patients with a BMI>46, with a percent change of -11.55 years per BMI unit.
Conclusion:
This analysis demonstrated significant differences in post-transplant survival outcomes by donor and recipient BMI. For donors, mean survival declined as BMI increased, albeit less dramatically in patients with a BMI>33. For recipients, mean survival steadily decreased as BMI increased, with the most extreme drop-off in mean survival occurring in patients with a BMI>46. Additional research should be conducted to determine the rationale for these trends and how donor and recipient BMI can be matched to optimize survival outcomes in liver transplantation.
