Nancy A. Melville

November 14, 2013

ATLANTA — People older than 55 years who donate a kidney are at no greater risk for death or cardiovascular disease than age-matched nondonors; however, the risk for end-stage renal disease is elevated, according to new research.

"These findings suggest that it is reasonable to accept healthy, well-informed, older adults as kidney donors," said senior author Peter Reese, MD, from the University of Pennsylvania in Philadelphia.

"But those individuals need to be aware of a small increased risk of end-stage renal disease, and kidney donors need to get careful medical follow-up throughout their lives," Dr. Reese told Medscape Medical News.

The waiting list for kidney transplants is increasingly composed of older adults. Because donors are often spouses or friends of those needing the kidney, they tend to be older as well.

As waiting times for cadaver kidneys increase, motivated healthy older people, who previously might not have been considered to be a viable option, are gaining favor in the transplant community.

Research on outcomes of kidney donation is lacking, particularly on how the age of the donor affects cardiovascular and renal outcomes.

Dr. Reese and his team looked at data from 1996 to 2006 to better understand the issue. They presented the results here at Kidney Week 2013: the American Society of Nephrology 46th Annual Meeting.

The researchers compared 3368 people who donated a kidney when they were older than 55 years with healthy participants in the Health and Retirement Study who had no significant comorbidities around the time of the donor's nephrectomy. The healthy participants were matched for age, body mass index, and demographic and economic characteristics.

At a median of 7.8 years after nephrectomy, there were no significant mortality differences between the 2 groups (P = .21), and there were no significant differences in the rates of death and cardiovascular events (P = .70).

End-Stage Renal Disease

Data on end-stage renal disease were only available for a subset of matched pairs, but the risk was significantly higher in older donors (hazard ratio, 7.4; 95% confidence interval, 2.91- 18.8; P < .001).

However, only 20 donors developed end-stage renal disease, "so kidney donation increases the risk of end-stage renal disease in a population of healthy older adults whose rate would be low, whether or not they donate a kidney," Dr. Reese reported.

Although older people who are considering donating a kidney should be counseled about the risk, they should also be informed "that their overall health outcomes are likely to be excellent, but they will have a small evaluation in the risk of end-stage renal disease," Dr. Reese said.

 
It is an important study because transplant physicians are increasingly concerned about putting living donors in harm's way Dr. Donald Hricik
 

This study sheds light on an issue of ongoing concern to physicians, said session comoderator Donald Hricik, MD, from Case Western Reserve University School of Medicine in Cleveland, Ohio.

"It is an important study because transplant physicians are increasingly concerned about putting living donors in harm's way," said Dr. Hricik.

He noted, however, that a major limitation of the study is the lack of data on glomerular filtration rates (GFRs) before and after donation.

"Many centers have an absolute cutoff for GFR, such as 80 mL/min, irrespective of age, even though we know that GFR declines with age," he told Medscape Medical News.

"This study would have been more interesting if they showed that even at the lower range of GFRs for age, there was no increased mortality. Without these data, I don't think the study promises to change current practice."

Dr. Reese received funding for the study from the American Society of Transplantation. Dr. Hricik has disclosed no relevant financial relationships.

Kidney Week 2013: the American Society of Nephrology 46th Annual Meeting: Abstract SA-OR001. Presented November 9, 2013.

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