Postop eGFR Tied To ESRD Risk In Living Kidney Donors

Living kidney donors' estimated glomerular filtration rate 6 months after donation (eGFR6) is associated with their risk of end-stage renal disease (ESRD), an observational study suggests.

"We've known for a few years now that kidney donors have a small, but real, increased long-term risk of renal failure," Dr. Allan Massie of Johns Hopkins University School of Medicine in Baltimore told Reuters Health by email. "Now, for the first time, we have a way of identifying donors who might be at higher risk, while they're still in good health, so that they can work with their doctor and change their lifestyle if necessary to preserve the function of their remaining kidney."

"Our findings can also reassure donors who are at lower risk," he noted.

"Finally, our work shows how important it is for transplant centers to continue to treat and follow up kidney donors to ensure their long-term health," he said. "The transplant hospital's responsibility to a donor doesn't end when the donor goes home after the surgery."

Dr. Massie and colleagues did a secondary analysis of deidentified data from from a registry of all living kidney donors in the US between 1999-2018 and modeled the association between eGFR6 and ESRD.

As reported in JAMA Surgery, 71,468 donors from among close to 110,000 were included. The mean age at donation was 42; 38% were male, 11% black; and close to half (47.2%) were first-degree relatives of the recipients. The median predonation eGFR was 98 mL/min/1.73 m2. At 6 months postdonation, the median was 63 mL/min/1.73 m2.

Predonation eGFR was not associated with postdonation ESRD in unadjusted or adjusted analyses, and was fully mediated by eGFR6 (adjusted hazard ratio, 1.00).

However, postdonation eGFR was associated with ESRD. Stratified by eGFR6, the cumulative incidence of ESRD at 15 years postdonation ranged from 11.7 per 10,000 donors with eGFR6 values greater than 70 mL/min/1.73 m2 to 33.1 per 10,000 donors with eGFR6 values of 50 mL/min/1.73 m2 or less.

After adjustment for age, race, sex, body mass index, and biological relationship, every 10 mL/min/1.73 m2 reduction in eGFR6 was associated with a 28% increased risk of ESRD (adjusted hazard ratio, 1.28).

Overall, based on the model that best fit the data, the authors concluded that eGFR6 was a better marker of postdonation eGFR than the change from predonation eGFR to eGFR6 values, or the ratio of eGFR6 to predonation eGFR.

Dr. Arthur Matas of the University of Minnesota in Minneapolis, coauthor of a related editorial, commented in an email to Reuters Health, "Kidney donors are heroes and every effort should be made to minimize short-and long-term risks."

"The two main causes of kidney failure in donors—similar to the general population—are type 2 diabetes and high blood pressure. These are diseases impacted by lifestyle," he said. "In the US, donor follow-up at 6, 12, and 24 months is required. However, recently published guidelines suggest that donors should have ongoing annual follow-up." (http://bit.ly/37IxudN)

"Kidney donation should be associated with a commitment to healthy lifestyle," he concluded.

—Marilynn Larkin

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