Strategies for assessing GFR and albuminuria in the living kidney donor evaluation

Predictive Value of Camera-based Donor Glomerular Filtration Rate Estimation on the Immediate Renal Allograft Outcome Following Live-related Renal Transplant: A Single-center Retrospective Study

Purpose of the Study

The purpose of this study was to assess the association of measured glomerular filtration rate (mGFR) using camera-based method with early transplant outcomes.

Methodology

Diethylenetriamine pentaacetate renograms of all voluntary kidney donors between January 2016 and December 2022 at Kasturba Hospital, Manipal, India, were retrieved for the study. Recipients' posttransplant biochemical parameters were collected and compared against donors with scaled mGFR >80 ml/min/1.73 m2 (Group 1) and with mGFR between 60 and 80 ml/min/1.73 m2 (Group 2). Donor-recipient pair age, anthropometric parameters, and their differences were also assessed against the immediate transplant outcome. Posttransplant immediate graft function was assessed by posttransplant nadir serum creatinine, day to achieve nadir serum creatinine, the incidence of slow graft or delayed graft function, and serum creatinine at 1-month posttransplantation. Recipients with serum creatinine of >2.5 mg/dl on posttransplant day 7 were taken as slow graft function.

Results

A total of 161 donor-recipient pairs were analyzed in the study. In recipients who showed persistently high serum creatinine posttransplant, older donor age(p < 0.001), higher difference in body mass index among the donor-recipient pair (p= 0.03), and mGFR <80ml/min (p < 0.001) were significantly associated. Slow graft function was significantly more in Group II recipients, with donors having mGFR <80ml/min as compared to Group I with mGFR >80 ml/min (37.3% vs. 10.6%) (P < 0.001).

Conclusions

Camera-based mGFR using Gates' formula is a reliable tool to predict inferior graft outcomes in the immediate posttransplant period. Kidneys from donors with mGFR of 60-80 mL/min/1.73 m2 are likely to experience slow graft function in the immediate posttransplant period.

A New Panel-Estimated GFR, Including β2-Microglobulin and β-Trace Protein and Not Including Race, Developed in a Diverse Population

RATIONALE AND OBJECTIVE

Glomerular filtration rate (GFR) estimation based on creatinine and cystatin C (eGFRcr-cys) is more accurate than estimated GFR (eGFR) based on creatinine or cystatin C alone (eGFRcr or eGFRcys, respectively), but the inclusion of creatinine in eGFRcr-cys requires specification of a person's race. β2-Microglobulin (B2M) and β-trace protein (BTP) are alternative filtration markers that appear to be less influenced by race than creatinine is.

STUDY DESIGN

Study of diagnostic test accuracy.

SETTING AND PARTICIPANTS

Development in a pooled population of 7 studies with 5,017 participants with and without chronic kidney disease. External validation in a pooled population of 7 other studies with 2,245 participants.

TESTS COMPARED

Panel eGFR using B2M and BTP in addition to cystatin C (3-marker panel) or creatinine and cystatin C (4-marker panel) with and without age and sex or race.

OUTCOMES

GFR measured as the urinary clearance of iothalamate, plasma clearance of iohexol, or plasma clearance of [51Cr]EDTA.

RESULTS

Mean measured GFRs were 58.1 and 83.2 mL/min/1.73 m2, and the proportions of Black participants were 38.6% and 24.0%, in the development and validation populations, respectively. In development, addition of age and sex improved the performance of all equations compared with equations without age and sex, but addition of race did not further improve the performance. In validation, the 4-marker panels were more accurate than the 3-marker panels (P < 0.001). The 3-marker panel without race was more accurate than eGFRcys (percentage of estimates greater than 30% different from measured GFR [1 - P30] of 15.6% vs 17.4%; P = 0.01), and the 4-marker panel without race was as accurate as eGFRcr-cys (1 - P30 of 8.6% vs 9.4%; P = 0.2). Results were generally consistent across subgroups.

LIMITATIONS

No representation of participants with severe comorbid illness and from geographic areas outside of North America and Europe.

CONCLUSIONS

The 4-marker panel eGFR is as accurate as eGFRcr-cys without requiring specification of race. A more accurate race-free eGFR could be an important advance.

Living Kidney Donation: Practical Considerations on Setting Up a Program

Living kidney donation represents the best treatment for end stage renal disease patients, with the potentiality to pre-emptively address kidney failure and significantly expand the organ pool. Unfortunately, there is still limited knowledge about this underutilized resource. The present review aims to describe the general principles for the establishment, organization, and oversight of a successful living kidney transplantation program, highlighting recommendation for good practice and the work up of donor selection, in view of potential short- and long-terms risks, as well as the additional value of kidney paired exchange programs. The need for donor registries is also discussed, as well as the importance of lifelong follow up.

Why Living Kidney Donor Candidates Are Turned Down? A Single-Center Cohort Study

Introduction Living donor kidney transplantation is the best replacement therapy for patients with end-stage renal disease. It offers more benefits than deceased donor transplantation. However, living kidney donors (LKDs) undergo an extensive evaluation to ensure their suitability for donation, and this can result in rejection of many potential donors. Aim The aim of this study was to recognize the reasons for declining LKDs in our Organ Transplant Center at King Abdulaziz Medical City. Settings and Design This was a retrospective study to determine the various reasons to reject an LKD at the Organ Transplant Center. Methods and Material All the LKDs from January 2016 to December 2019 were included. Declined donors were reviewed and data were obtained from the electronic database and transplant nephrology shared files. Statistical analysis We performed data analysis using SPSS version 24.0 (IBM Corp., Armonk, NY, USA). Data for continuous variables were presented as mean ± standard deviation and were compared using t-test. Categorical variables were presented as frequencies and percentages; chi-square test was used to test for main association and then Bonferroni adjustment was used for post-hoc testing. Statistical significance was considered if a two-tailed p-value of <0.05 was achieved. Results A total of 410 potential LKDs were evaluated, of whom 241 (58.8%) successfully underwent donor nephrectomy and 169 (41.2%) were unable to proceed for kidney donation. The most common reasons for rejection of LKDs were medical (47.9%) followed by immunological reasons mainly blood group incompatibility (19.5%). Other reasons were donor withdrawal (15.4%), recipient-related reasons (7.1%), surgically unfit to proceed for nephrectomy (4.7%), or psychological reasons (2.3%). Conclusions A significant proportion of potential LKDs did not complete the kidney donation process due to medical, immunological, and surgical reasons. In addition, a proportion of LKDs decided to withdraw at some point during the evaluation process. Investing in donors' educational programs and implementing a standardized evaluation process are essential to increase LKDs pool.

Adherence to Medical Appointments Among Living Kidney Donors After Donation Under a Monitored Approach and Long-term Clinical Outcomes: A Brazilian Single-center Cohort Study

BACKGROUND

There is little information about living donor long-term follow-up among Brazilian living donors. The aim of this study was to evaluate the main outcomes among living donors and to measure their adherence to regular medical appointments.

METHODS

This is a Brazilian single-center cohort study that included 397 living donors with 87.1 months of follow-up and measured adherence to clinical appointments. Before 2010, the appointments were scheduled only spontaneously; after that an approach was structured to check the returns of donors, who were monitored actively. We also evaluated long-term outcomes such as survival and chronic kidney disease development and, secondarily, the incidences of hypertension, diabetes mellitus (DM), and dyslipidemia after donation.

RESULTS

The donors' adherence to annual clinical appointments was 75.8% (54.7% of them presenting annual regularity). Before 2010 the adherence was lower than 40%; 10-year cumulative incidences of hypertension, DM, and dyslipidemia were 20.4%, 5.7%, and 23.5%, respectively. The crude mortality was 1% and 10-year donor survival was 98.5%. The incidence of chronic kidney disease 5 years after donation was 19%, with 16.4% of patients staged in 3a and 2.6% in 3b.

CONCLUSION

A structured approach to check donor returns to long-term clinical appointments has doubled the adherence to visits returns (compared to historical data). We identified lower incidence of arterial hypertension and DM among donors as compared with the incidence of arterial hypertension and DM in the Brazilian general population, but the 5-year chronic kidney disease incidence was considered high, taking into consideration data that have been published in the last years.

Assessment of Glomerular Filtration Rate and End-Stage Kidney Disease Risk in Living Kidney Donor Candidates: A Paradigm for Evaluation, Selection, and Counseling

Living donor kidney transplantation is the preferred treatment option for ESRD. However, recent data suggest a small increase in the long-term risk of kidney failure in living kidney donors when compared to healthy nondonors. These data have led to a need for reconsideration of how donor candidates are evaluated and selected for donation. A Kidney Disease: Improving Global Outcomes (KDIGO) work group completed a comprehensive clinical practice guideline for evaluation of living kidney donor candidates in 2017, based on systematic evidence review, de novo evidence generation, and expert opinion. Central to the evaluation framework is assessment of glomerular filtration rate (GFR), which is used to screen for kidney disease and aid the prediction of long-term kidney failure risk after donation. Accurate estimation of the level of GFR and risk of kidney failure, and communication of estimated risks, can support evidence-based donor selection and shared decision-making. In this review, we discuss approaches to optimal GFR estimation in the donor evaluation process, long-term risk projection, and risk communication to donor candidates, integrating recommendations from the new KDIGO guideline, other recent literature, and experience from our own research and practice. We conclude by highlighting topics for further research in this important area of transplant medicine.

Summary of Kidney Disease: Improving Global Outcomes (KDIGO) Clinical Practice Guideline on the Evaluation and Care of Living Kidney Donors

Kidney Disease: Improving Global Outcomes (KDIGO) engaged an evidence review team and convened a work group to produce a guideline to evaluate and manage candidates for living kidney donation. The evidence for most guideline recommendations is sparse and many "ungraded" expert consensus recommendations were made to guide the donor candidate evaluation and care before, during, and after donation. The guideline advocates for replacing decisions based on assessments of single risk factors in isolation with a comprehensive approach to risk assessment using the best available evidence. The approach to simultaneous consideration of each candidate's profile of demographic and health characteristics advances a new framework for assessing donor candidate risk and for defensible shared decision making.