For the hundreds of thousands of Americans whose kidneys have stopped functioning, there are two options: lifelong dialysis or kidney transplantation.  Dialysis is time consuming, carries serious risks, and only partially replaces the functions of a healthy kidney.  Patients live longer and have a much better quality of life after receiving a kidney transplant.  The difficulty with transplantation is that donated organs are scarce and transplants are more likely to be successful with living donors than with recently deceased donors.

Physicians and potential donors have been concerned about the health risks involved in kidney donation.  Besides the short-term risk of the surgery, there was a concern that kidney donation over subsequent decades would lead to all the bad consequences of other kinds of kidney injury: high blood pressure, worsening kidney function, eventual kidney failure, and shorter life span.

Because of that, potential kidney donors have to go through a meticulous screening process.  Anyone with any risk factors for developing kidney disease later in life is excluded.  So no one donates if he has diabetes, high blood pressure, protein in the urine (an early sign of kidney disease) or decreased kidney function.

Because of these precautions, it’s been assumed that kidney donors do well after donation and live a normal life, but this has never been actually studied in a large number of donors.  There were also worrisome reports of a few kidney donors who eventually lost all kidney function and needed dialysis themselves.  Was this a consequence of their donation or a random event that would have happened anyway?

A large study in this week’s New England Journal of Medicine attempted to answer the question.  It followed the health, kidney function, and quality of life of thousands of kidney donors and compared them to people in the general population who had the same age, sex and race as each donor.  The results were that the donors had the same longevity, general health, and better kidney function than the general population.  And they have excellent quality of life, on average.  This was trumpeted in the general press as great news for kidney donors.

Not so fast.  I think that this is a perfect example of why it’s important, when possible, to read the original article rather than rely on a newspaper science reporter to filter information for you.  The results are not nearly as heartening as reported.  Remember, all the kidney donors were very carefully screened before being allowed to donate.  So as a group they were much healthier then the general population.  They were then compared with the general population and found that their health and lifespan is no worse.  That’s not good; they should have done much better.  Headlines declared that kidney donors have normal life spans, but before their donation they should have had better than normal life spans.  That’s not a reassuring bit of news about kidney donation.

The authors of the study are very forthright about this important limitation to their findings, but you only find that out if you read their discussion in the original article.

Studies that more accurately determine the long term risk of kidney donation are currently ongoing.  In the meantime, potential donors should not take false comfort from this study.

Learn more:

New England Journal of Medicine article: Long-Term Consequences of Kidney Donation

Los Angeles Times article:  Kidney donors have a normal life span, study finds