March 9, 2010 — Live kidney donation is safe and free from significant long-term excess mortality, according to new research published in the March 10 issue of the Journal of the American Medical Association.
"More than 6000 healthy US individuals every year undergo nephrectomy for the purposes of live donation," write Dorry L. Segev, MD, PhD, from the Johns Hopkins School of Medicine, Baltimore, Maryland, and colleagues. "However, safety remains in question because longitudinal outcome studies have occurred at single centers with limited generalizability."
The goal of this study was to compare long-term death rates between donors and nondonors, to study national trends in live donor selection and outcome, and to estimate short-term operative risk in various strata of live donors.
The investigators examined the outcomes of 80,347 live kidney donors in the United States between April 1, 1994, and March 31, 2009, who were drawn from a mandated national registry. A matched cohort of 9364 individuals was drawn from participants in the third National Health and Nutrition Examination Survey. The nondoners were as similar to the donor cohort as possible and were as free as possible from contraindications to live donation.
The median follow-up was 6.3 years (interquartile range, 3.2 - 9.8 years).
During the study period there were 25 deaths within 90 days of live kidney donation.
The risk for death in the first 90 days after live donor nephrectomy was 3.1 per 10,000 donors (95% confidence interval [CI], 2.0 - 4.6). In comparison, the risk for death in the matched cohort was 0.4 per 10,000 persons (95% CI, 0.1 - 1.1; P < .001).
Surgical mortality did not change during the 15 years of the study period, despite differences in practice and patient selection, the researchers note.
The study also found that surgical mortality was higher in men than women (5.1 vs 1.7 per 10,000 donors; risk ratio [RR], 3.0; 95% CI, 1.3 - 6.9; P = .007), in black vs white and Hispanic donors (7.6 vs 2.6 and 2.0 per 10,000 donors, respectively; RR, 3.1; 95% CI, 1.3 - 7.1; P = .01) and in donors with hypertension vs those without hypertension (36.7 vs 1.3 per 10,000 donors; RR, 27.4; 95% CI, 5.0 - 149.5; P < .001).
However, the long-term risk for death was no higher for live donors than for age- and comorbidity-matched nondonors.
The benefits of live kidney donation for the recipient have been well documented. It is incumbent on the transplant community to show that these lives are not saved at the cost of placing the donors at risk, the researchers comment.
The limitations of the study are availability of data (information about education, body mass index, hypertension, and smoking was only available in later periods), duration of follow-up, and statistical artifacts resulting from an overmatched cohort, the researchers note.
"Regardless of what physiologic changes might occur in a healthy adult after kidney donation, our findings of similar long term survival between donors and healthy comparison patients suggests that these physiologic changes do not result in premature death," the investigators conclude.
Although more studies are needed to understand these changes, "the current practice of live kidney donation should continue to be considered a reasonable and safe modality for addressing the profound shortage in deceased donor organs."
The authors have disclosed no relevant financial relationships.