Obese kidney failure patients receive survival benefit from transplantation

Most obese individuals with kidney failure can prolong their lives by receiving a kidney transplant, although this survival benefit is lower in severely obese individuals. That's the conclusion of a new study published in the American Journal of Transplantation. The findings will hopefully decrease differences in access to transplantation for obese patients.

Obesity is increasing in patients with kidney failure. In some studies, obese kidney failure patients who are on dialysis have a lower risk of dying prematurely than non-obese patients. In contrast, obese kidney transplant recipients have a higher risk of dying prematurely than non-obese recipients. Therefore determining the survival benefit of transplantation in obese transplant recipients is an important issue.

Using data from the United States between 1995 and 2007, John Gill, MD, MS, of the University of British Columbia, in Vancouver, and his colleagues determined the risk of premature death in transplant recipients grouped by body mass index (BMI) compared with transplant candidates with the same BMI who were on the transplant waiting list. The analysis included 208,498 patients, and obesity was defined as a BMI of 30 kg/m2 or higher.

Among the major findings:

• Obese patients with a BMI of 30 to 39 kg/m2 derived a similar survival advantage from transplantation as non-obese patients, which equated to more than a 66 percent reduced risk of dying within one year of transplantation.
• Obese patients with a BMI of 40 or higher derived a lower survival advantage from transplantation (a 48 percent reduced risk of dying within one year), and a survival advantage was uncertain in Black patients with a BMI of 40 or higher.
• Differences in obese compared with non-obese patients were not as profound with transplantations using kidneys from live donors.
• The risk of dying early after transplantation was greater in obese compared with non-obese patients.

"Our study shows that obese patients derive a survival advantage from transplantation, and obesity should not exclude patients from consideration of transplantation," said Dr. Gill. "Also, improved early post-transplant care may help reduce the early risk of death in obese patients, and living donor transplantation may be a useful strategy to mitigate the risks of transplantation in obese transplant candidates."