Impact of Obesity on Kidney Transplant Outcomes in Older Adults

Background: The prevalence of obesity in older patients undergoing kidney transplantation is increasing. Older age and obesity are associated with higher risks of complications and mortality post-transplantation. The optimal management of this group of patients remains undefined. Methods: We retrospectively analyzed the United Network for Organ Sharing database of adults >= 70 years of age undergoing primary kidney transplant from January 1, 2014, to December 31, 2022. We examined patient and graft survival stratified by body mass index (BMI) in 3 categories, <30 kg/m(2), 30 to 35 kg/m(2), and >35 kg/m(2). We also analyzed other risk factors that impacted survival. Results: A total of 14,786 patients >= 70 years underwent kidney transplantation. Of those, 9,731 patients had a BMI <30 kg/m(2), 3,726 patients with a BMI of 30 to 35 kg/m(2), and 1,036 patients with a BMI >35 kg/m(2). During the study period, there was a significant increase in kidney transplants in patients >= 70 years old across all BMI groups. Overall, patient survival, death-censored graft survival, and all-cause graft survival were lower in obese patients compared with nonobese patients. Multivariable analysis showed worse patient survival and graft survival in patients with a BMI of 30 to 35 kg/m(2), a BMI >35 kg/m(2), a longer duration of dialysis, diabetes mellitus, and poor functional status. Conclusion: Adults >= 70 years should be considered for kidney transplantation. Obesity with a BMI of 30 to 35 kg/m(2) or >35 kg/m(2), longer duration of dialysis, diabetes, and functional status are associated with worse outcomes. Optimization of these risk factors is essential when considering these patients for transplantation.