Kidney donors at higher risk for hypertension which may halt post-donation eGFR rise
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Researchers of a recently published study found kidney donors had a greater risk for hypertension than non-donors. In addition, those who developed hypertension experienced a plateau in the usual post-donation eGFR increase.
“Living kidney donation is associated with an increased risk of end-stage kidney disease compared to healthy non-donors, with hypertension as one of the most frequent concomitant etiologies,” Courtenay M. Holscher, MD, of the department of surgery at Johns Hopkins University School of Medicine, and colleagues wrote. “To improve informed consent and physiologic understanding, it is critical that we not only clarify the risk of hypertension attributable to donation and the timeline of incident post-donation hypertension, but also clarify the impact of post-donation hypertension on subsequent eGFR. It is also possible that race impacts the risk of developing post-donation hypertension.”
Researchers conducted a longitudinal multicenter study that compared 1,295 living kidney donors to a cohort of 8,233 non-donors. For both groups, the risk of hypertension and the association between incident hypertension and eGFR trajectory were examined. Race was considered as a possible effect modifier.
Participants were followed for a maximum of 27 years (median for donors, 6 years and six eGFR measurements; median for non-donors, 23 years and five eGFR measurements).
Researchers found that, at 15 years, 8% of Caucasian non-donors and 9% of African American non-donors had hypertension compared with 23% of Caucasian donors and 42% of African American donors. Overall, kidney donation was associated with a 19% higher risk of hypertension. While researchers observed that African Americans had a greater risk (27%) than whites, the association between kidney donation and hypertension did not vary by race.
“In other words,” they elaborated, “while the baseline risk of hypertension was higher for African Americans, the impact of donating a kidney on the development of hypertension was the same for African Americans and Caucasians.”
Regarding eGFR, researchers found a decline in non-donors over time regardless of race (-0.4 mL/min/year for white donors vs. -0.3 mL/min/year for African American donors) and that the decline steepened after incident hypertension (-0.8 mL/min/year vs. -0.9 mL/min/year). Race was also not associated with eGFR trajectory for donors, with an increase occurring after donation (mean, 0.4 mL/min/year and 0.6 mL/min/year) that plateaued after incident hypertension (mean, 0 mL/min/year and -0.2 mL/min/year) for both white and African American donors, respectively. Due to the plateau after developing hypertension, researchers suggested incident hypertension is a risk factor in eGFR following kidney donation.
“We identified incident hypertension as a risk factor in post-donation eGFR which merits aggressive preventive measures and careful management, as it is associated with cessation of the increase in eGFR following donation,” they concluded. “While intuitive, this finding strengthens our understanding of kidney physiology following living kidney donation. Further work is needed to identify opportunities and best practices for preventing, recognizing and managing hypertension in living kidney donors.”
In a related editorial, William S. Asch, MD, PhD, of Yale University School of Medicine, expressed disappointment that the study did not examine the potential association between donor-use of antihypertensive medications and GFR not rising as expected.
“Hence,” he wrote, “it can not be determined at this time whether the GFR trajectory change is directly triggered by a biological mechanism attributable to hypertension or confounded by the use of particular classes of antihypertensive medications.”
Despite this uninvestigated area, Asch anticipated that these findings will be influential to the entire transplant community, “including the informed consent process, and policy decisions regarding obligations to the parent center to provide truly long-term follow up for their living donors.”
He added, “These findings also have the potential to shift the public and media’s perception of the safety of living kidney donation, especially when coupled with earlier reports already indicating an increased risk of ESKD in living donors.” – by Melissa J. Webb
Disclosures: Holscher reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.
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