New research from the University of Birmingham, funded by the British Heart Foundation (BHF), has found that very small reductions in kidney function are directly linked to subtle heart and blood vessel damage. These results show for the first time that the heart damage seen in people with Chronic Kidney Disease is a direct result of their reduced kidney function.

Published in Hypertension, the study which was also funded by the NIHR/Wellcome Clinical Research Facility and Queen Elizabeth Hospital Birmingham Charity, looked to see if healthy people who had donated a kidney had experienced any adverse changes in their heart and blood vessels as a result. Researchers tracked 68 kidney donors and 56 comparable non-donors for over a year.

The research found that, even in very healthy people, a small reduction in kidney function (such as following donation of a kidney) is associated with an enlarged left-side of the heart, which makes the heart stiffer and impairs its ability to contract, pointing to a clear link between reductions in kidney function and cardiovascular disease. However, these effects were extremely small and at an individual level the extra risk associated with the changes is very small.

These results could have significant consequences for people suffering with Chronic Kidney Disease (CKD). In England in 2008/9 there were over 1.5 million people registered with CKD, though the actual number is likely much higher. People with CKD have impaired cardiac function to the extent that this is often the cause of premature death. This study, by demonstrating that there is small but measurable heart and blood vessel damage following kidney donation in otherwise healthy people, shows that in patients with CKD, poor kidney function has a direct adverse effect on heart function.

Dr William Moody, a BHF Research Fellow at Queen Elizabeth Hospital and the University of Birmingham, who worked on the study said, “It should be noted that the effects on the kidney donors were very small and no studies of people who have donated a kidney have shown a cardiovascular risk that is higher than that of the general population.”

Professor Jeremy Pearson, Associate Medical Director at the British Heart Foundation said, “While the adverse effects in the kidney donors are small, the study suggests strongly that identification of the mechanisms involved could provide new avenues to reduce the progressive impairment of heart function seen in patients with chronic kidney disease. However it is important to note that these findings should not put anyone off donating a kidney, as those individuals are highly selected as healthy subjects and effects of kidney donation will still not even get them to an ‘average’ risk level”

Dr William Moody added, “Early stage kidney disease is a public health problem because it is common and carries an increased risk of heart and circulatory disease. A major research effort is needed to understand this risk and to find measures to prevent this damage. For now, people with blood tests showing slightly reduced kidney function should certainly consider discussing heart disease risk with their doctors and consider how best to reduce this.”