Obese Donors Have Good Kidney Function at Six Months and One Year after Kidney Donation; Long-Term Effects Less Clear

Kidney function in obese kidney donors remains strong one year after donation, although long-term effects on renal function are uncertain, said Peter Reese and his colleagues at the University of Pennsylvania-Philadelphia at a Renal Week session.

As transplant centers work to maximize appropriate live donor transplantation, uncertainties remain concerning the potential risks of accepting kidneys from donors with obesity or other risk factors for future kidney disease. Also unclear are risks obese donors may face during and after the surgical procedure.

To shed light on this issue, Reese and his colleagues studied the use of kidneys donated by live obese and non-obese individuals at transplant centers across the United States. Of the 5300 donors studied, nearly 1200 (22.5 percent) were obese. The authors analyzed 2004–2005 registry data from the Organ Procurement and Transplantation Network.

The investigators found that obesity is common among live donors, especially among black and Hispanic donors, who also are more likely to develop kidney disease. Compared with non-obese donors, obese donors also had higher blood pressure prior to kidney donation. Peri-operative outcomes were not worse for obese donors.

To compare the health of obese and non-obese donors after surgery, the investigators measured blood pressure, hypertension status, and kidney function at six months and one year after the surgery.

Obese donors had slightly higher blood pressure and were more likely to be hypertensive than non-obese donors at follow-up, but they were less likely to have poor kidney function. The study’s major limitation was missing data on donor outcomes at follow-up. Approximately 40 percent of donors had no data on kidney function reported at six months.

Although the study shows that obese individuals have health outcomes after kidney donation similar to those for other donors, the long-term risks are uncertain.

“It is our hope that researchers will pursue longitudinal studies on the health outcomes of obese kidney donors 10 to 20 years after donation,” Reese said. “It is important to help clarify these risks because many donors really want to help loved ones. Obese donors should be educated about the limitations in what we know about long-term outcomes after kidney donation. Nonetheless, our data suggest that obesity alone should not be a contraindication to live kidney donation. This finding is important because the prevalence of obesity is increasing.”

The study, titled “Peri-Operative Complications and 1-Year Outcomes for Obese Live Kidney Donors” was part of a session on “Care Delivery in Kidney Transplantation and the Living Kidney Donor.”