Obesity Effects on Kidney Transplant Outcomes

Obesity has emerged as a major determinant of both short- and long-term outcomes in kidney transplant recipients. Excess adiposity modifies recipient physiology, increasing the risk of perioperative surgical complications such as wound infection, fascial dehiscence and lymphoceles, and prolonging hospital stay. Elevated body mass index (BMI) is associated with delayed graft function, which reflects a temporary loss of allograft filtration capacity requiring dialysis within one week of transplantation. In the longer term, obesity contributes to metabolic disturbances including new-onset diabetes after transplantation (NODAT) and dyslipidaemia, and heightens cardiovascular risk. Immunosuppressive regimens may further exacerbate weight gain, creating a feedback loop that impairs graft survival. Conversely, some data suggest an “obesity paradox” in which overweight recipients exhibit comparable or even superior survival to lean counterparts, underscoring the complexity of adiposity as a risk factor. Amid an expanding global burden of obesity, transplant programmes grapple with the challenge of defining BMI eligibility thresholds, balancing the risks of exclusion against the survival benefit conferred by transplantation over dialysis. Weight-management strategies, including lifestyle intervention and bariatric surgery, are being explored to mitigate risks, although evidence on their impact on graft and patient outcomes remains limited. A nuanced understanding of adipose tissue distribution, inflammation and metabolic reserve is essential to personalise recipient selection and optimise peri-transplant care.

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Obesity Effects on Kidney Transplant Outcomes publication trend

The graph below shows the total number of articles in obesity effects on kidney transplant outcomes across all publications each year (not limited to Nature Index journals).

Technical terms

Body mass index (BMI): A measure of body fat calculated as weight in kilograms divided by height in metres squared, used to classify underweight, normal weight, overweight and obesity.

Delayed graft function (DGF): A postoperative complication defined by the need for dialysis within the first week after transplantation, indicating impaired immediate graft performance.

Death-censored graft survival: The duration of allograft function excluding cases where patient death with a functioning graft is the end point, thus isolating organ survival.

New-onset diabetes after transplantation (NODAT): The development of diabetes mellitus in transplant recipients without prior history of diabetes, often linked to immunosuppressive therapy and obesity.

References

1. Body mass index and outcome in renal transplant recipients: a systematic review and meta-analysis. BMC Medicine (2015).
2. Higher recipient body mass index is associated with post-transplant delayed kidney graft function. Kidney International (2011).
3. Body Mass Index, Waist Circumference and Mortality in Kidney Transplant Recipients. American Journal of Transplantation (2010).
4. The Impact and Treatment of Obesity in Kidney Transplant Candidates and Recipients. Canadian Journal of Kidney Health and Disease (2015).
5. Recipient obesity as a risk factor in kidney transplantation. BMC Nephrology (2022).
6. Renal transplantation outcomes in obese patients: a French cohort-based study. BMC Nephrology (2021).