Few studies have assessed the health of living kidney donors after donation. Now research funded by the NIH’s National Institute of Diabetes and Digestive and Kidney Diseases has found that kidney function in donors did not deteriorate three years after donation, while healthy volunteers in a control group experienced expected age-related declines in kidney function. Results were published in July in the American Journal of Kidney Diseases.
The study included 182 kidney donors and 173 control group participants who were eligible for donation and completed follow-up visits for 36 months. In the control group, two measures of kidney function— measured glomerular filtration rate (mGFR) and estimated glomerular filtration rate (eGFR)—declined. However, in the donor group, these measures increased, which suggests improvement.
“This ongoing study is important because of the lack of information regarding long-term health consequences of kidney donation, its careful design using an appropriate comparison group, and its attention to evaluation of laboratory tests including those related to bone health,” said Paul Kimmel, senior advisor in NIDDK’s Division of Kidney, Urologic and Hematologic Diseases.
Additionally, blood pressure was similar between the two groups, and total protein in the urine did not differ between donors and controls. Donors also had lower urine albumin-creatinine ratios
—used to assess and monitor kidney disease—than the control group. That marker increased among donors over time, but not in the control group. Cholesterol levels increased slightly among all study participants over time and did not differ between the two groups.
The study had some limitations. Those in the control group couldn’t be screened as thoroughly as donors for underlying kidney abnormalities, making it possible that the donors were healthier than controls from the outset. Also, it may take more than three years for effects of kidney donation to appear, a reason to continue future research. This type of research must also be performed in more diverse populations of living donors, since this study included few people from minority groups.
The results also showed subtle changes in markers of bone health in the donor group that researchers will continue to monitor. The significance of these changes is unknown and suggests a need for future research.
The principal investigator for this study is Bertram L. Kasiske, MD, professor of medicine at the University of Minnesota’s Department of Medicine.