Invite all donors to participate in follow-up studies

Garg and colleagues provide new data that contribute greatly to our understanding of the long term consequences of living kidney donation.1 However, although they tried to match donors with non-donor controls, it is hard to determine whether the groups were truly comparable because information on blood pressure is lacking.

A meta-analysis from the same group reported a 5 mm Hg increase in systolic blood pressure in kidney donors about 10 years after nephrectomy.2 Taken together, these data suggest that blood pressure rises significantly after kidney donation but without an accompanying increase in cardiovascular morbidity or mortality.1 2 If this finding is confirmed, kidney donors would be the only group of patients yet studied in whom a rise in blood pressure has not been accompanied by an increase in mortality. In the general population, even a 2 mm Hg increase in systolic blood pressure confers a long term increase in mortality from stroke and cardiovascular disease of 10% and 7%, respectively.3 Thus, in kidney donors, either the data on blood pressure or on mortality are probably incorrect.

Nevertheless, even if blood pressure does increase it can be treated easily. The hidden danger is that, in our desire to improve outcomes in patients with established renal failure, we falsely reassure ourselves that the donor is not adversely affected. To safeguard the expanding practice of living kidney donation, we suggest inviting all donors to participate prospectively in pathophysiological and epidemiological studies.