Obesity and Kidney Donation

Over 90,000 patients with advanced renal failure are waiting for a suitable kidney for a transplant. There are simply too few cadaveric kidneys available, and not enough suitable living donors, either.

Live donor kidney donation is considered safe for persons who are in good health. Long-term follow-up studies of persons who donated kidneys as long as 50 years ago have shown past donors live just as long as one would expect. To ensure that donors are not put at risk, potential kidney donors are screened for good health before they are allowed to donate.

Persons who are obese may be rejected as potential kidney donors even though they are otherwise in good health. That’s because obesity is a known risk factor for kidney disease later in life. There are no hard-and-fast weight limits to be allowed to donate a kidney because no one knows whether donating a kidney would actually increase an obese person’s chances of kidney disease later in life. Nevertheless, many kidney transplant centers aren’t willing to take the risk. More than half of all kidney transplant centers set a Body Mass Index (BMI) of 35 as an upper limit for an acceptable donor; 10% set the limit even lower, at a BMI of 30.

According to a presentation at a recent clinical meeting of the National Kidney Foundation, one transplant center found that 37% of its potential living kidney donors were obese (BMI>30) and another 22% were morbidly obese (BMI>35). Although the morbidly obese potential donors received nutritional counseling and follow-up, fewer than 15% lost enough weight and eventually were allowed to donate a kidney.

Obesity is on the rise in this country. It’s a shame that the potential pool of living kidney donors, never large enough to begin with, may shrink even further with the rise in obesity.