BALTIMORE, Dec. 31 (UPI) -- Some obese people spend a longer time on kidney transplant waiting lists than people within normal weight ranges, a U.S. study shows.

Researchers at Johns Hopkins University in Baltimore said morbidly obese people -- those more than 100 pounds above their ideal weight -- were on transplant waiting lists for five years, two years longer than patients of normal weight, Ivanhoe Newswire reported.

Study author Dr. Dorry Segev said research indicated obese patients might be turned down because of added cost and poorer outcomes associated with transplants in overweight patients.

"Patients understandably believe that being placed on the transplant waiting list is an implicit promise of fair, unbiased treatment under a transparent allocation scheme," said Segev, a transplant surgeon. "Unfortunately, the system that has been established nationally may not be living up to that promise."

The findings may have an economic basis as well, Segev said. Medicare, the main insurer for kidney transplants, pays a set amount for the operation, regardless of the patient's overall health and costs associated with the procedure, which could increase with obese patients.

The findings were reported in the recent Journal of the American Society of Nephrology Online.