Commentary on Risks of Living Kidney Donation

Current State of Knowledge on Core Outcomes Important to Donors

Introduction

In this evidence-based nephrology review, Lentine et al. (¹) discuss the growing evidence regarding short- and long-term risks of living kidney donation. Adopting a patient-centered approach to characterizing and prioritizing these risks, the authors identify four potential risk categories: (1) kidney health (including risk of ESKD and progressive GFR decline), (2) surgical risks (including perioperative morbidity and mortality), (3) psychosocial risks (including health-related quality of life and stress), and (4) financial risks (including direct and indirect nonmedical costs). Information on these risks is essential for informed decision making and consent for donation. We summarize their findings as follows.

• The risk of ESKD after kidney donation is similar to that of the general population but significantly higher than the risk among healthy nondonors.
• The risks of long-term CKD and ESKD are greater among black donors compared with white donors, analogous to the disparity in these outcomes among the general population.
• Several prediction tools have been developed to estimate the long-term risk of ESKD for a potential kidney donor on the basis of demographic and clinical factors.
• Perioperative mortality after live kidney donation is very low at roughly three patients per 10,000 donations within 90 days.
• Perioperative complications of any severity occur in roughly 17%–18% of donations, with major complications affecting 2.5%–3.0% of live donors.
• On average, live donors experience no decline in psychosocial health after kidney donation, although a minority (<20%) of donors do report new mood disturbances or fear of kidney failure within 2 years.
• Most living kidney donors incur some direct financial costs from donation, including costs related to travel, lost time from work, and dependent care. Financial concerns of donors are greater among younger and lower-income individuals.

Teaching Statement: Evaluating Effect Modification on the Relative and Absolute Scales

The comprehensive review by Lentine et al. (¹) summarizes important risks associated with live kidney donation. A topical question in this area is whether the risk of developing ESKD differs by race. One study cited in the review evaluated >95,00 live kidney donors and a matched group of nondonors in the United States (²). The investigators determined the incidence rates of ESKD by race/ethnicity (Table 1).

Table 1. - Incidence of ESKD associated with live kidney donation

Race/Ethnicity	Donor Status	Cumulative Incidence of ESKD at 15 yr per 10,000
Black	Donor	74.7
Black	Nondonor control	23.9
Hispanic	Donor	32.6
Hispanic	Nondonor control	6.7

Reprinted from ref. ², with permission.

Consider the differential effect of live kidney donation on the incidence of ESKD by race/ethnicity on the relative risk scale:On the basis of the difference in relative risks, kidney donation is associated with a modestly greater incidence of ESKD among Hispanic donors compared with black donors. However, the differential effect of kidney donation on ESKD differs when attributable risk is used as the measure of effect:On the attributable risk scale, live kidney donation is associated with a greater incidence of ESKD among black donors. Which measure is correct? Both analyses are “correct,” but they show contrasting interpretations of effect modification depending on the scale used to quantify the association of interest. The differential size of associations on the relative scale suggests that the potential effect of live donation on ESKD is modestly higher for individual donors who are Hispanic compared with those who are black. Yet, the differential associations of kidney donation with ESKD on the additive scale suggest that donation may cause a greater number of patients with ESKD among the population of black donors, for whom the background incidence of ESKD is highest.

Disclosures

None.