NEW YORK (Reuters Health) - Accepting living donors with mild hypertension or proteinuria for kidney transplants would lead to only a modest increase in transplantation rates, researchers report. Raising awareness among potential donors would have more impact, they say.

In their study reported in the February issue of the American Journal of Kidney Diseases, Dr. Martin Karpinski, from the University of Manitoba, in Winnipeg, and colleagues found that accepting donors with these mild conditions would increase transplantation rates by just 3%.

"The number of donors who might actually have a condition mild enough that they could accept the risk of donation is relatively small compared to the other barriers," Dr. Karpinski told Reuters Health. "So it's important to go on promoting overall living kidney donation and explore how we can overcome the barrier of immunologic incompatibility."

Many transplantation programs exclude potential living kidney donors with mild hypertension or proteinuria because these conditions are associated with an increased risk for chronic kidney disease and end-stage renal disease. While the level at which they can be considered "acceptable" remains controversial, there has been increasing pressure to include "marginal donors," according to the authors.

"There are many different strategies that are being pursued to increase the number of living kidney donors and this is one of them," said Dr. Karpinski. "So we wanted to quantify what the impact might be, relative to what the impact of other strategies might be."

To do so, Dr. Karpinski and his team studied data on 352 wait-listed recipients at four Canadian transplantation centers, analyzing the reasons for living kidney donor exclusion.

The results showed that only 35% of patients on these waiting lists actually had one or more potential living donors come forward. "This number is quite low and shows that a big effort could already be done at this level -- to increase the overall number of living donors," said Dr. Karpinski.

Among the 180 potential living donors evaluated, the primary reason for exclusion was immunologic: positive cross-match (32%) or blood group type incompatibility (22%). The team found that hypertension or proteinuria were less common reasons for exclusion (17%).

The investigators defined potentially acceptable hypertension as a blood pressure level less than 150/100 mm Hg (or less than 140/90 mm Hg if administered a single antihypertensive medication) and acceptable proteinuria as 0.15 to 0.30 g/d protein.

Based on these standards, of the 31 donors excluded for hypertension/proteinuria, only 13 had results in the acceptable range.

"Acceptance of these donors would have resulted in transplantation of 3% (12 of 352) of the wait-list population," the team concludes.

Am J Kidney Dis 2006;47:317-323

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