'Normal for now' or 'at future risk': a double standard for selecting young and older living kidney donors.

Transplant centers medically evaluate potential living kidney donors in part to determine their baseline remaining lifetime risk for end stage renal disease (ESRD). If baseline risk is increased by the presence of a risk factor for ESRD, donation is often refused. However, as only about 13% of ESRD occurs in the general population by age 44, a normal medical evaluation cannot be expected to significantly reduce the 7% lifetime risk for a 'normal' 25-year-old black donor or the 2-3% risk for a similar white donor. About half of newly diagnosed ESRD in the United States occurs by age 65, and about half of that is from diabetic nephropathy, which takes about 25 years to develop. Therefore, the remaining baseline lifetime risk for ESRD is significantly lower in the normal, nondiabetic 55-year-old donor candidate. Some older donors with an isolated medical abnormality such as mild hypertension will be at lower or about the same overall baseline lifetime risk for ESRD as are young 'normal' donor candidates. Transplant centers use a 'normal for now' standard for accepting young donors, in place of the long-term risk estimates that must guide selection of all donors.