Correspondence
Long-Term Consequences of Kidney Donation
N Engl J Med 2009; 360:2370-2372May 28, 2009DOI: 10.1056/NEJMc090444
- Article
To the Editor:
The outcomes for living kidney donors, shown in the study by Ibrahim et al. (Jan. 29 issue),1 are reassuring. Key strengths of the study are the large sample and the long follow-up. However, limitations include a highly selected and ethnically homogeneous population and the lack of acknowledgment that living donors today have an increasing number of health risk factors such as obesity. Also missing are considerations of the effect of unique regional practices and rates of end-stage renal disease (ESRD), socioeconomic influences, access to health care, educational level, and lifestyle choices. We would argue that the good survival and lower overall rate of ESRD as compared with the rates in the general population may have been due to the optimal condition of the donors at the time of their donation. The rate of ESRD should have been reported according to geographic area, since the rate varies substantially across the country. Furthermore, the ideal control group is not the general population but a group of people living in the same area who have been evaluated as candidates for donation but who did not donate. Even with the excellent research design, this study cannot be taken as the final word. Potential donors of nonwhite background need to be very carefully screened and counseled.2,3
3 ReferencesConnie L. Davis, M.D.
Matthew Cooper, M.D.
United Network for Organ Sharing, Richmond, VA 23219
cdavis@u.washington. edu 1
Ibrahim HN ,Foley R ,Tan L , et al. Long-term consequences of kidney donation. N Engl J Med 2009;360:459-469
Free Full Text | Web of Science | Medline2
Parasuraman R ,Venkat KK . Utility of estimated glomerular filtration rate in live kidney donation. Clin J Am Soc Nephrol 2008;3:1608-1609
CrossRef | Web of Science | Medline3
Gibney EM ,Parikh CR ,Garg AX . Age, gender, race, and associations with kidney failure following living kidney donation. Transplant Proc 2008;40:1337-1340
CrossRef | Web of Science | Medline
To the Editor:
As a primary care physician and recent nondirected kidney donor, I found the article by Ibrahim et al. to be generally reassuring, yet also discomforting, about health care after donation. Of the 255 donors who voluntarily underwent examinations, 82 (32%) had blood pressures higher than 140/90 mm Hg. Of these, 19 (23%) had undiagnosed hypertension or were not taking antihypertensive medicine, and another 12 (15%) had poorly controlled hypertension despite taking antihypertensive medicine. Thus, 38% of examined donors with hypertension had poorly controlled blood pressure. Of the 11 donors known to have ESRD, 3 of the 7 with a known cause (43%) had hypertensive nephropathy. On average, systolic blood pressure increases by 5 mm Hg after donation.1 Thus, it can be anticipated that a few donors may have a much higher increase and that hypertensive nephropathy will develop in some of them. Health care for donors is provided primarily by providers other than those in transplantation centers; these clinicians must do better to prevent and manage hypertension and to prevent hypertensive nephropathy. I am aware of only one guideline for people with solitary kidneys that includes a defined target blood pressure and explicit management strategies.2
2 ReferencesWilliam L. Freeman, M.D., M.P.H.
Northwest Indian College, Bellingham, WA 98226
wfreeman@nwic.edu 1
Boudville N ,Prasad GVR ,Knoll G , et al. Meta-analysis: risk for hypertension in living kidney donors. Ann Intern Med 2006;145:185-196
Web of Science | Medline2
National Institute of Diabetes and Digestive and Kidney Diseases. Solitary kidney. (Accessed May 7, 2009, at http://kidney.niddk.nih.gov/kudiseases/pubs/solitarykidney/.)
To the Editor:
Ibrahim et al. report that ESRD developed in 11 of 3698 donors, a risk described as similar to that in the general population. Not described or discussed is the alarming rate of ESRD among nonwhite donors. Extrapolating from Table 3 of the article, approximately 2% of donors were nonwhite but were not further characterized. If this assumption is correct, ESRD developed in 8 of 3624 white donors (0.2%) and in 3 of 74 nonwhite donors (4.1%) (P<0.001). Sample size may contribute to this unacceptable rate, but the trend is consistent with the data of Gibney et al.,1 who found both that black kidney donors were at greater risk for the development of ESRD than white donors and that 90% of donors in whom ESRD developed within 10 years after donation were black. It would have been useful if Ibrahim et al. had provided more descriptive data about donors in whom ESRD developed; however, in the absence of such data, one might well conclude that evaluation processes for living donors have not adequately identified the risk of ESRD after kidney donation for nonwhites.
1 ReferenceLainie Friedman Ross, M.D., Ph.D.
J. Richard Thistlethwaite, Jr., M.D., Ph.D.
University of Chicago, Chicago, IL 60637
lross@uchicago.edu 1
Gibney EM ,King AL ,Maluf DG ,Garg AX ,Parikh CR . Living kidney donors requiring transplantation: focus on African Americans. Transplantation 2007;84:647-649
CrossRef | Web of Science | Medline
To the Editor:
Ibrahim et al. report that in a subgroup of 255 live kidney donors, older age was associated with a glomerular filtration rate (GFR) lower than 60 ml per minute per 1.73 m2 of body-surface area. Iohexol GFR was measured at only a single point in time after donation, probably introducing a selection bias. At our center, 539 living donors who received a transplant between 1994 and 2006 were followed in a longitudinal rather than a cross-sectional manner. Unlike Ibrahim et al., we observed no such age-dependent decrease in GFR (Figure 1Figure 1
Long-Term Follow-up of Glomerular Filtration Rate (GFR) in 539 Live Kidney Donors, Divided into Three Age Groups.). Our results show a decrease in GFR (as estimated with the use of the Modification of Diet in Renal Disease [MDRD] formula) after donation in all three age groups but with stable kidney function over the years. Our findings support the conclusions of Ibrahim et al. and also indicate that kidney donation by older donors may be considered relatively safe over time, since kidney function does not appear to decline progressively.Leonienke F.C. Dols, M.D.
Willem Weimar, M.D., Ph.D.
Jan N.M. IJzermans, M.D., Ph.D.
Erasmus Medical Center, 3015 CE Rotterdam, the Netherlands
j.ijzermans@erasmusmc. nl Author/Editor Response
Davis and Cooper note that the Minnesota donor cohort is almost entirely white, whereas in the United States as a whole, 86% of donors are white.1 They also comment on the ideal control group for kidney donors. As we note in our discussion, the ideal group would have been persons who were deemed suitable for donation but who did not donate. We compared the rate of incident ESRD among our donors with the rate among whites in the United States; most of our donors (>60%) are residents of Minnesota. In 2006, the rate of incident ESRD in Minnesota was almost identical to that in the rest of the country (359.8 and 363.2 cases per million, respectively). In previous years, the rate was 20 to 40 cases per million lower in Minnesota than in the rest of the country.2 We hope that the Renal and Lung Donors Evaluation (RELIVE) study (ClinicalTrials.gov number, NCT00608283), which will report on more than 8000 kidney donors, with better minority representation and more comparable controls, will address some of these concerns.
Freeman points out the critical finding that some donors had hypertension that was poorly controlled or undiagnosed. We strongly agree that there is a need to aggressively monitor and treat blood-pressure elevations in all kidney donors.
Ross and Thistlethwaite note that 3 of the 11 donors in whom ESRD developed were nonwhite. One was a black woman, one an Asian woman, and one a Native American man. The Asian donor had hypertension-related ESRD; the cause was unknown in the case of the other two. There were 93 black donors, 39 Asian donors, and 76 Native-American donors, yielding an incidence of ESRD of 1.1%, 2.6%, and 1.3%, respectively. Although the numbers are too small to draw conclusions, these data clearly indicate that race or ethnic background should be considered in the overall assessment of risk, an area that our study could not fully address.
Dols et al. note that there was no age-related decline in GFR in their longitudinal studies of GFR in donors. We have measured GFR longitudinally in 38 of our donors and noted a decline of 0.59±3.84 ml per minute per year, a rate that is similar to that observed in our cross-sectional measurement of GFR. At the second GFR measurement, GFR had decreased in 24 donors, had stayed the same in 2, and had actually risen in 12, suggesting that a GFR decline with aging may not be universal.
2 ReferencesHassan N. Ibrahim, M.D.
Arthur J. Matas, M.D.
University of Minnesota, Minneapolis, MN 55414
ibrah007@umn.edu 1
Gibney EM ,King AL ,Maluf DG ,Garg AX ,Parikh CR . Living kidney donors requiring transplantation: focus on African Americans. Transplantation 2007;84:647-649
CrossRef | Web of Science | Medline2
Renal Data System. USRDS 2008 annual data report: atlas of chronic kidney disease and end-stage renal disease in the United States. Bethesda, MD: National Institute of Diabetes and Digestive and Kidney Diseases, 2008.
- Citing Articles (1)
Citing Articles
1
Connie L. Davis. (2012) Living Kidney Donor Follow-up: State-of-the-art and Future Directions. Advances in Chronic Kidney Disease 19:4, 207-211
