Evaluation of Kidney Function and Structure in Potential Living Kidney Donors: Implications for the Donor and Recipient

Transplant Clinician Opinions on Use of Race in the Estimation of Glomerular Filtration Rate

BACKGROUND AND OBJECTIVES

Current race-based eGFR calculators assign a higher eGFR value to Black patients, which could affect the care of kidney transplant candidates and potential living donors.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted a survey of staff at adult kidney transplant centers in the United States (December 17, 2020 to February 28, 2021) to assess opinions on use of race-based eGFR equations for waitlisting and living donor candidate evaluation, availability of serum cystatin C testing and measured GFR, and related practices.

RESULTS

Respondents represented 57% (124 of 218) of adult kidney transplant programs, and the responding centers conducted 70% of recent kidney transplant volume. Most (93%) programs use serum creatinine-based eGFR for listing candidates. However, only 6% of respondents felt that current race-based eGFR calculators are appropriate, with desire for change grounded in concerns for promotion of health care disparities by current equations and inaccuracies in reporting of race. Most respondents (70%) believed that elimination of race would allow more preemptive waitlisting for Black patients, but a majority (79%) also raised concerns that such an approach could incur harms. More than one third of the responding programs lacked or were unsure of availability of testing for cystatin C or measured GFR. At this time, 40% of represented centers did not plan to remove race from eGFR calculators, 46% were planning to remove, and 15% had already done so. There was substantial variability in eGFR reporting and listing of multiracial patients with some Black ancestry. There was no difference in GFR acceptance thresholds for Black versus non-Black living donors.

CONCLUSIONS

This national survey highlights a broad consensus that extant approaches to GFR estimation are unsatisfactory, but it also identified a range of current opinions.

KDIGO Clinical Practice Guideline on the Evaluation and Care of Living Kidney Donors

The 2017 Kidney Disease: Improving Global Outcomes (KDIGO) Clinical Practice Guideline on the Evaluation and Care of Living Kidney Donors is intended to assist medical professionals who evaluate living kidney donor candidates and provide care before, during and after donation. The guideline development process followed the Grades of Recommendation Assessment, Development, and Evaluation (GRADE) approach and guideline recommendations are based on systematic reviews of relevant studies that included critical appraisal of the quality of the evidence and the strength of recommendations. However, many recommendations, for which there was no evidence or no systematic search for evidence was undertaken by the Evidence Review Team, were issued as ungraded expert opinion recommendations. The guideline work group concluded that a comprehensive approach to risk assessment should replace decisions based on assessments of single risk factors in isolation. Original data analyses were undertaken to produce a "proof-in-concept" risk-prediction model for kidney failure to support a framework for quantitative risk assessment in the donor candidate evaluation and defensible shared decision making. This framework is grounded in the simultaneous consideration of each candidate's profile of demographic and health characteristics. The processes and framework for the donor candidate evaluation are presented, along with recommendations for optimal care before, during, and after donation. Limitations of the evidence are discussed, especially regarding the lack of definitive prospective studies and clinical outcome trials. Suggestions for future research, including the need for continued refinement of long-term risk prediction and novel approaches to estimating donation-attributable risks, are also provided.In citing this document, the following format should be used: Kidney Disease: Improving Global Outcomes (KDIGO) Living Kidney Donor Work Group. KDIGO Clinical Practice Guideline on the Evaluation and Care of Living Kidney Donors. Transplantation. 2017;101(Suppl 8S):S1-S109.

GFR Evaluation in Living Kidney Donor Candidates

Evaluation of GFR, required in the evaluation of living kidney donor candidates, is now receiving increasing emphasis because recent data demonstrate increased risk of kidney disease after donation, including a small increase in the risk of kidney failure. The international guideline development group, Kidney Disease Improving Global Outcomes, recently published a comprehensive set of recommendations for living donor evaluation, with three recommendations regarding GFR. (1) Donor candidacy is evaluated in light of long-term risk, in which GFR is one of many factors. ESRD is considered a central outcome, and a method for estimating long-term risk of ESRD in donor candidates is described. (2) Two GFR thresholds are used for decision-making: a high threshold (≥90 ml/min per 1.73 m2) to accept and a low threshold (<60 ml/min per 1.73 m2) to decline, with 60-89 ml/min per 1.73 m2 as an intermediate range in which the decision to accept or decline is made on the basis of factors in addition to GFR. (3) GFR is evaluated using several methods available at the transplant center, including estimating equations and clearance measurements. We review the rationale for the guideline recommendations, principles of GFR measurement and estimation, and our suggestions for implementation.