Donating a kidney increases a person's risk for hypertension, regardless of race, researchers said at the American Society of Nephrology's Annual Kidney Week in San Diego.
On the other hand - and contrary to some reports - kidney donors are not at higher risk for diabetes compared with healthy non-donors, Dr Dorry Segev from Johns Hopkins Medical Institutions, Baltimore, Maryland, and colleagues reported.
"We wanted to do this study because we don't know much about the risk of hypertension after kidney donation," said Dr Segev. "More specifically, we don't know if people who donated a kidney, and are thus living with one kidney, have a higher risk of hypertension than people who did not donate a kidney and are thus living with two kidneys."
Dr Segev and his team studied 1 046 individuals who donated kidneys at Johns Hopkins between 1970 and 2011 and compared them with matched, healthy controls drawn from two large cohort studies where patients underwent extensive medical evaluation and follow-up.
Any donor is at risk
With a median follow-up of close to seven years, and after adjustment for potential confounding factors, they found that live donors had 35% higher risk of hypertension after kidney donation compared with healthy controls (p<0.01).
Overall, 19% of donors developed hypertension: 26% of blacks, and 18% of non-blacks.
But on multivariate analysis, the effect was more pronounced in non-black donors (adjusted hazard ratio 1.44 compared to non-black controls, p<0.01) than in African American donors (aHR 1.01, p = 0.9).
"The fact that Caucasian donors had higher rates of hypertension is interesting because it's African American donors who we classically worry more about with regard to hypertension," Dr Segev said.
"In other words, African American donors have higher rates of hypertension after kidney donation than Caucasian donors, but our study suggests that this is not because of the donation, but because African Americans in general have higher rates of hypertension than Caucasians," he said.
Four percent of donors (8% black, 3% non-black) developed diabetes. These rates were similar among non-donors.
"Our findings are important for counselling individuals who are considering donation about the long-term risks associated with donation, but also are reassuring that African Americans aren't more at risk for this effect than any other donors," Dr Segev said.
(Reuters Health, November 2012)
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