Impact of Obesity on Kidney Transplant Outcomes in Older Adults

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.

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/m², 30 to 35 kg/m², and >35 kg/m². We also analyzed other risk factors that impacted survival.

A total of 14,786 patients ≥70 years underwent kidney transplantation. Of those, 9,731 patients had a BMI <30 kg/m², 3,726 patients with a BMI of 30 to 35 kg/m², and 1,036 patients with a BMI >35 kg/m². 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/m², a BMI >35 kg/m², a longer duration of dialysis, diabetes mellitus, and poor functional status.

Adults ≥70 years should be considered for kidney transplantation. Obesity with a BMI of 30 to 35 kg/m² or >35 kg/m², 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.