Study assesses potential health complications for obese kidney donors

Individuals who are obese face certain risks when donating their kidneys, but their kidney function remains strong one year later, according to a paper being presented at the American Society of Nephrology's 41st Annual Meeting and Scientific Exposition in Philadelphia, Pennsylvania.

As the waiting list for kidney transplants grows, transplant centers are working to facilitate more live donor transplantations. However, there are many unanswered questions related to the potential long-term risks of kidney donation for donors with risk factors for future kidney disease - such as obesity.

To investigate the issue, Peter Reese, MD, and his colleagues at the University of Pennsylvania in Philadelphia, Pennsylvania, report on the use of kidneys donated by live obese and non-obese individuals at transplant centers across the United States. The study included 2004-2005 registry data from the Organ Procurement and Transplantation Network. In all, the investigators analyzed data from more than 5,300 donors, among whom nearly 1,200 (22.5%) were obese.

The study revealed that obesity is common among live donors, particularly among African- and Hispanic-American donors, who also are more likely to develop kidney disease. Additionally, the research indicates that compared with non-obese donors, obese donors have higher blood pressure prior to kidney donation.

To compare the health of obese and non-obese donors after surgery, the investigators measured blood pressure, hypertension status, and kidney function at six and twelve months after kidney donation. Obese donors had slightly higher blood pressure and were more likely to be hypertensive than non-obese donors. However, obese donors did not have worse kidney function than non-obese donors.

The study's major limitation was missing data on donor outcomes at follow-up. For instance, approximately 40% of donors had no data on kidney function reported at 6 months.

The authors stress that while this study indicates that obese individuals do not suffer from serious short-term adverse outcomes following kidney donation, the long-term risks to obese donors are uncertain. Uncovering these risks is important because many potential donors are strongly motivated to help loved ones but should also be aware of the risks to themselves. "Transplant centers must work hard to inform live donors about risks, but there are many unknowns," said Reese. He noted that studies on health outcomes at 10 or 20 years after donation would help clarify the risks to obese donors, but such long-term data are currently not available.