A study published in the BMJ has said that donating kidney does not raise heart disease risk. The study thus alleviates fear and offer important safety reassurances to living kidney donors, their recipients and transplant professionals.
In the general population, there is a strong link between
reduced kidney function and an increased risk of cardiovascular disease. Given
that people who donate a kidney lose half their kidney mass, doctors need to
know whether this risk extends to them.
Previous studies have suggested no increase in risk but a
consensus has not yet been reached. So researchers based in Canada, Australia
and the USA
set out to determine whether people who donate a kidney have an increased risk
of cardiovascular disease.
The study involved 2,028 people in Ontario, Canada
who donated a kidney between 1992 and 2009 and 20,280 healthy non-donors for
The research team reviewed the medical records of each donor
and linked them to national healthcare databases to monitor major
cardiovascular events over an average of 6.5 years.
Further analysis according to year of donation was carried
out to identify any trends in risk over a longer time period.
Despite reduced kidney function in the donors, they found a
lower risk of death or first major cardiovascular event in donors compared with
non-donors (2.8 versus 4.1 events per 1,000 person years).
There was also no significant difference in the risk of
major cardiovascular events between donors and non-donors (1.7 versus 2 events
per 1,000 person years).
There was no increased risk among earlier donors or those who
donated at an older age. The authors say this is likely to be because only
healthy people are considered for living kidney donation and, in our region,
they receive regular medical follow up after donating.
The risk of major cardiovascular events in people who donate
a kidney is no higher in the first decade after transplantation than in matched
non-donors, say the authors.
It is possible that an association between living donation
and cardiovascular disease risk does exist, but takes much longer to manifest,
they add. For this reason, they recommend ongoing monitoring of donors.
However, they say their study "adds to the available
evidence base supporting the safety of the practice amongst carefully selected
In an accompanying editorial, researchers at the University of Michigan say the study resolves the
uncertainty that persists about the full extent of risks assumed by living
kidney donors and "makes an important contribution to our understanding of the
long term consequences of living kidney donation."