Kidney-Failure Risk Projection for the Living Kidney-Donor Candidate

Expanding Opportunities for Living Donation: Recommendations From the 2023 Santander Summit to Ensure Donor Protections, Informed Decision Making, and Equitable Access

A strategic vision toward global convergence in transplantation must encourage and remove barriers to living organ donation and transplantation. Here, we discuss deliberations of a working group of the 2023 Santander Summit charged with formulating recommendations for the safe expansion of living donor kidney transplantation and living donor liver transplantation worldwide. Living donor kidney transplantation has grown to be the preferred treatment for advanced kidney failure. Living donor liver transplantation emerged more recently as a strategy to reduce waitlist mortality, with adoption influenced by cultural factors, regional policies, clinical team experience, and the maturity of regional deceased donor transplant systems. Barriers to living donor transplantation span domains of education, infrastructure, risk assessment/risk communication, and financial burden to donors. Paired donor exchange is a growing option for overcoming incompatibilities to transplantation but is variably used across and within countries. Effectively expanding access to living donor transplantation requires multifaceted strategies, including improved education and outreach, and measures to enhance efficiency, transparency, and shared decision making in donor candidate evaluation. Efforts toward global dissemination and vigilant oversight of best practices and international standards for the assessment, informed consent, approval, and monitoring of living donors are needed. Fostering greater participation in paired exchange requires eliminating disincentives and logistical obstacles for transplant programs and patients, and establishing an ethical and legal framework grounded in World Health Organization Guiding Principles. Sharing of best practices from successful countries and programs to jurisdictions with emerging practices is vital to safely expand the practice of living donation worldwide and bring the field together globally.

Performance of the New CKD-EPI Creatinine-and Cystatin C-based Glomerular Filtration Rate Estimation Equation in Living Kidney Donor Candidate

Background

Accurate preoperative evaluation of renal function in living kidney donor candidates (LKDCs) is crucial to prevent kidney failure after nephrectomy. We examined the performance of various estimated glomerular filtration rate (eGFR) equations, including the new chronic kidney disease epidemiology collaboration (CKD-EPI) equation in LKDCs.

Methods

We analyzed 752 LKDCs who were assessed for measured GFR by inulin clearance as part of routine pretransplant examination from 2006 to 2020. CKD-EPI2012 from cystatin C (CKD-EPI12cys), CKD-EPI2021 from creatinine (CKD-EPI21cr), CKD-EPI21cr-cys, Japanese modified (JPN) eGFRcr, and JPN eGFRcys were compared in determining the suitability for LKDCs.

Results

CKD-EPI12cys had the lowest absolute and relative biases, with higher P30 and P10, followed by JPN eGFRcys, CKD-EPI21cr, and CKD-EPI21cr-cys. The root mean square error was least for CKD-EPI12cys, then JPN eGFRcys, CKD-EPI21cr-cys, CKD-EPI21cr, and JPN eGFRcr. CKD-EPI21cr, CKD-EPI12cys, and CKD-EPI21cr-cys estimated GFR higher, whereas JPN eGFRcr estimated GFR lower. At the threshold of 90 mL/min/1.73 m2, CKD-EPI21cr had the highest percentage of misclassification at 37.37%, whereas JPN eGFRcr had the lowest percentage of misclassification at 6.91%. Using the age-adapted approach, JPN eGFRcr had the lowest percentage of misclassification into overestimation at 7.31%. All eGFR had >5.0%, and CKD-EPI21cr had the highest percentage of misclassification at 21.94%. Conversely, CKD-EPI21cr-cys had the lowest percentage of misclassification into underestimation at 3.19%, both at the threshold of 90 mL/min/1.73 m2 and the age-adapted approach. JPN eGFRcr had the highest percentage at 33.38% and 40.69%, respectively.

Conclusions

In evaluating the renal function of Japanese LKDCs, the new CKD-EPI equation had a lower rate of underestimation but a relatively high rate of overestimation. New GFR estimation formulas are needed to be tailored to each ethnic group to enhance the accuracy and reliability of donor selection processes.

Research hotspots and future trends in lipid metabolism in chronic kidney disease: a bibliometric and visualization analysis from 2004 to 2023

Background

Disorders of lipid metabolism play a key role in the initiation and progression of chronic kidney disease (CKD). Recently, research on lipid metabolism in CKD has rapidly increased worldwide. However, comprehensive bibliometric analyses in this field are lacking. Therefore, this study aimed to evaluate publications in the field of lipid metabolism in CKD over the past 20 years based on bibliometric analysis methods to understand the important achievements, popular research topics, and emerging thematic trends.

Methods

Literature on lipid metabolism in CKD, published between 2004 and 2023, was retrieved from the Web of Science Core Collection. The VOSviewer (v.1.6.19), CiteSpace (v.6.3 R1), R language (v.4.3.2), and Bibliometrix (v.4.1.4) packages (https://www.bibliometrix.org) were used for the bibliometric analysis and visualization. Annual output, author, country, institution, journal, cited literature, co-cited literature, and keywords were also included. The citation frequency and H-index were used to evaluate quality and influence.

Results

In total, 1,285 publications in the field of lipid metabolism in CKD were identified in this study. A total of 7,615 authors from 1,885 institutions in 69 countries and regions published articles in 466 journals. Among them, China was the most productive (368 articles), and the United States had the most citations (17,880 times) and the highest H-index (75). Vaziri Nosratola D, Levi Moshe, Fornoni Alessia, Zhao Yingyong, and Merscher Sandra emerged as core authors. Levi Moshe (2,247 times) and Vaziri Nosratola D (1,969 times) were also authors of the top two most cited publications. The International Journal of Molecular Sciences and Kidney International are the most published and cited journals in this field, respectively. Cardiovascular disease (CVD) and diabetic kidney disease (DKD) have attracted significant attention in the field of lipid metabolism. Oxidative stress, inflammation, insulin resistance, autophagy, and cell death are the key research topics in this field.

Conclusion

Through bibliometric analysis, the current status and global trends in lipid metabolism in CKD were demonstrated. CVD and DKD are closely associated with the lipid metabolism of patients with CKD. Future studies should focus on effective CKD treatments using lipid-lowering targets.

Evaluation and Long-Term Follow-Up of Living Kidney Donors

The evaluation of living kidney donor candidates is a complex and lengthy process. Donor candidates face geographic and socioeconomic barriers to completing donor evaluation. Inequities in access to living donations persist. With a growing demand for kidney transplants and a shortage of living donors, transplant centers are more permissive of accepting less-than-ideal donor candidates. Donors have an increased lifetime risk of kidney failure, but the absolute risk increase is small. Efforts are needed to support donor candidates to complete donor nephrectomy safely and efficiently and receive optimal follow-up care to prevent risk factors for kidney disease and detect complications early. In this article, the authors address key elements of donor kidney evaluation, including current living donation policy requirements and transplant center practices. The authors present a simplified comprehensive practical approach to help guide providers in completing donor evaluation and follow-up care with best outcomes possible.

Renal outcome of living kidney donors aged more than 70 years

BACKGROUND

The number of marginal living kidney donors has increased. Medically complex donors who have hypertension, older age, or low estimated glomerular filtration rate (eGFR) have been more likely to be used.

METHODS

We conducted a retrospective cohort study of living kidney donors at a single center. We analyzed 309 living donors and divided them into three groups: group with older donors (aged ≥70 years) (n = 41), middle-aged (aged 46-69 years) (n = 239), and young donors (aged <46 years) (N = 29). Donor factors associated with chronic kidney disease (CKD) stage 3b or worse within 5 years post-donation were investigated.

RESULTS

Of the 309 live donors, 86 (27.8%) developed CKD stage3b or worse within 5 years post-donation. The incidence of CKD stage3b or worse within 5 years post-donation was significantly higher in older donor (p < 0.01). Cox regression models revealed that older donor ages and lower eGFR were significantly related to the development of CKD stage3b or worse, independent of comorbidities such as obesity and hypertension [hazard ratio (95% CI); 4.59 (1.02-20.6), p = 047, 0.95 (0.94-0.96), p ≤ 0.01, respectively]. However, recovery of eGFR 4-5 years after donation was noted in the middle-aged and older donor groups, whereas the level of eGFR remained unchanged in the young group.

CONCLUSIONS

Older donors tend to develop CKD stage3b within 5 years post-donation but with the potential of recovery. Healthy older people (aged ≥70 years) could be candidates for living donors under careful monitoring of kidney function after donation.

Comparison of Kidney Graft Function and Survival in an Emulated Trial With Living Donors and Brain-Dead Donors

Living donation (LD) transplantation is the preferred treatment for kidney failure as compared to donation after brain death (DBD), but age may play a role. We compared the 1-year estimated glomerular filtration rate (eGFR) after kidney transplantation for recipients of LD and DBD stratified by recipient and donor age between 2015 and 2018 in a matched cohort. The strength of the association between donation type and 1-year eGFR differed by recipient age (P interaction < 0.0001). For LD recipients aged 40-54 years versus same-aged DBD recipients, the adjusted odds ratio (aOR) for eGFR ≥60 mL/min/1.73 m2 was 1.48 (95% CI: 1.16-1.90). For DBD recipients aged ≥ 60 years, the aOR was 0.18 (95% CI: 0.12-0.29) versus DBD recipients aged 40-54 years but was 0.91 (95% CI: 0.67-1.24) versus LD recipients aged ≥60 years. In the matched cohort, 4-year graft and patient survival differed by donor age and type. As compared with DBD grafts, LD grafts increased the proportion of recipients with 1-year eGFR ≥60 mL/min/1.73 m2. Recipients aged ≥60 years benefited most from LD transplantation, even if the donor was aged ≥60 years. For younger recipients, large age differences between donor and recipient could also be addressed with a paired exchange program.

Non-Maleficence toward Young Kidney Donors: A Call for Stronger Ethical Standards and Associated Factors in Multidisciplinary Nephrology Teams

BACKGROUND

The rising frequency of live kidney donations is accompanied by growing ethical concerns as to donor autonomy, the comprehensiveness of disclosure, and donors' understanding of long-term consequences.

AIM

To explore donors' satisfaction with the ethical competence of multi-professional nephrology teams regarding disclosure of donation consequences to live kidney donors.

METHODS

A cross-sectional study was performed among Israeli live kidney donors who had donated a kidney in two hospitals that belonged to the Ministry of Health's Transplantation Center one year after the donation, from December 2018 to December 2020. Data collection was conducted online and through face-to-face interviews with the donors in their native language (Hebrew or Arabic).

RESULTS

Overall, 91 live kidney donors aged 18-49 years were enrolled. Of those, 65.9% were males, and 54.9% were academic donors. Among the live kidney donors, 59.3% reported that the motivation behind the donation was a first-degree family member vs. 35.2% altruistic and 5.5% commercial. Only 13.2% reported that the provided disclosure adequately explained the possible consequences of living with a single kidney. Approximately 20% of the participants reported that the disclosure included information regarding their risk of developing ESRD, hypertension, and proteinuria. The donors reported a low mean of the index score that indicates a low follow-up by the physician after the donation (mean = 1.16, SD = 0.37). The mean GFR level was significantly lower in the post-donation period one year following a kidney donation (117.8 mL/min/1.73 m2) compared with the pre-donation period (84.0 mL/min/1.73 m2), p < 0.001.

CONCLUSION

Our findings display that donors' satisfaction with the ethical competence of multi-professional nephrology teams regarding the disclosure of donation consequences to live kidney donors is low. This study indicates that donors are at an increased risk of worsening kidney functions (creatinine and GFR), and BMI. Our findings underscore the imperative to advise donors that their condition may worsen over time and can result in complications; thus, they should be monitored during short and long-term follow-up periods. This study was not registered.

Hypertension and Kidney Function After Living Kidney Donation

Importance

Recent guidelines call for better evidence on health outcomes after living kidney donation.

Objective

To determine the risk of hypertension in normotensive adults who donated a kidney compared with nondonors of similar baseline health. Their rates of estimated glomerular filtration rate (eGFR) decline and risk of albuminuria were also compared.

Design, Setting, and Participants

Prospective cohort study of 924 standard-criteria living kidney donors enrolled before surgery and a concurrent sample of 396 nondonors. Recruitment occurred from 2004 to 2014 from 17 transplant centers (12 in Canada and 5 in Australia); follow-up occurred until November 2021. Donors and nondonors had the same annual schedule of follow-up assessments. Inverse probability of treatment weighting on a propensity score was used to balance donors and nondonors on baseline characteristics.

Exposure

Living kidney donation.

Main Outcomes and Measures

Hypertension (systolic blood pressure [SBP] ≥140 mm Hg, diastolic blood pressure [DBP] ≥90 mm Hg, or antihypertensive medication), annualized change in eGFR (starting 12 months after donation/simulated donation date in nondonors), and albuminuria (albumin to creatinine ratio ≥3 mg/mmol [≥30 mg/g]).

Results

Among the 924 donors, 66% were female; they had a mean age of 47 years and a mean eGFR of 100 mL/min/1.73 m2. Donors were more likely than nondonors to have a family history of kidney failure (464/922 [50%] vs 89/394 [23%], respectively). After statistical weighting, the sample of nondonors increased to 928 and baseline characteristics were similar between the 2 groups. During a median follow-up of 7.3 years (IQR, 6.0-9.0), in weighted analysis, hypertension occurred in 161 of 924 donors (17%) and 158 of 928 nondonors (17%) (weighted hazard ratio, 1.11 [95% CI, 0.75-1.66]). The longitudinal change in mean blood pressure was similar in donors and nondonors. After the initial drop in donors' eGFR after nephrectomy (mean, 32 mL/min/1.73 m2), donors had a 1.4-mL/min/1.73 m2 (95% CI, 1.2-1.5) per year lesser decline in eGFR than nondonors. However, more donors than nondonors had an eGFR between 30 and 60 mL/min/1.73 m2 at least once in follow-up (438/924 [47%] vs 49/928 [5%]). Albuminuria occurred in 132 of 905 donors (15%) and 95 of 904 nondonors (11%) (weighted hazard ratio, 1.46 [95% CI, 0.97-2.21]); the weighted between-group difference in the albumin to creatinine ratio was 1.02 (95% CI, 0.88-1.19).

Conclusions and Relevance

In this cohort study of living kidney donors and nondonors with the same follow-up schedule, the risks of hypertension and albuminuria were not significantly different. After the initial drop in eGFR from nephrectomy, donors had a slower mean rate of eGFR decline than nondonors but were more likely to have an eGFR between 30 and 60 mL/min/1.73 m2 at least once in follow-up.

Trial Registration

ClinicalTrials.gov Identifier: NCT00936078.

First experiences with machine learning predictions of accelerated declining eGFR slope of living kidney donors 3 years after donation

BACKGROUND

Living kidney donors are screened pre-donation to estimate the risk of end-stage kidney disease (ESKD). We evaluate Machine Learning (ML) to predict the progression of kidney function deterioration over time using the estimated GFR (eGFR) slope as the target variable.

METHODS

We included 238 living kidney donors who underwent donor nephrectomy. We divided the dataset based on the eGFR slope in the third follow-up year, resulting in 185 donors with an average eGFR slope and 53 donors with an accelerated declining eGFR-slope. We trained three Machine Learning-models (Random Forest [RF], Extreme Gradient Boosting [XG], Support Vector Machine [SVM]) and Logistic Regression (LR) for predictions. Predefined data subsets served for training to explore whether parameters of an ESKD risk score alone suffice or additional clinical and time-zero biopsy parameters enhance predictions. Machine learning-driven feature selection identified the best predictive parameters.

RESULTS

None of the four models classified the eGFR slope with an AUC greater than 0.6 or an F1 score surpassing 0.41 despite training on different data subsets. Following machine learning-driven feature selection and subsequent retraining on these selected features, random forest and extreme gradient boosting outperformed other models, achieving an AUC of 0.66 and an F1 score of 0.44. After feature selection, two predictive donor attributes consistently appeared in all models: smoking-related features and glomerulitis of the Banff Lesion Score.

CONCLUSIONS

Training machine learning-models with distinct predefined data subsets yielded unsatisfactory results. However, the efficacy of random forest and extreme gradient boosting improved when trained exclusively with machine learning-driven selected features, suggesting that the quality, rather than the quantity, of features is crucial for machine learning-model performance. This study offers insights into the application of emerging machine learning-techniques for the screening of living kidney donors.

Prediction of post-donation renal function using machine learning techniques and conventional regression models in living kidney donors

BACKGROUND

Accurate prediction of renal function following kidney donation and careful selection of living donors are essential for living-kidney donation programs. We aimed to develop a prediction model for post-donation renal function following living kidney donation using machine learning.

METHODS

This retrospective cohort study was conducted with 823 living kidney donors between 2009 and 2020. The dataset was randomly split into training (80%) and test sets (20%). The main outcome was the post-donation estimated glomerular filtration rate (eGFR) 12 months after nephrectomy. We compared the performance of machine learning techniques, traditional regression models, and models from previous studies. The best-performing model was selected based on the mean absolute error (MAE) and root mean square error (RMSE).

RESULTS

The mean age of the participants was 45.2 ± 12.3 years, and 48.4% were males. The mean pre-donation and post-donation eGFRs were 101.3 ± 13.0 and 68.8 ± 12.7 mL/min/1.73 m2, respectively. The XGBoost model with the eGFR, age, serum creatinine, 24-h urine creatinine, 24-h urine sodium, creatinine clearance, cystatin C, cystatin C-based eGFR, computed tomography volume of the remaining kidney/body weight, normalized GFR of the remaining kidney measured through a diethylenetriaminepentaacetic acid scan, and sex, showed the best performance with a mean absolute error of 6.23 and root mean square error of 8.06. An easy-to-use web application titled Kidney Donation with Nephrologic Intelligence (KDNI) was developed.

CONCLUSIONS

The prediction model using XGBoost accurately predicted the post-donation eGFR after living kidney donation. This model can be applied in clinical practice using KDNI, the developed web application.

Impact of donor smoking history on kidney transplant recipient outcomes: A systematic review and meta-analysis

BACKGROUND

Impact of donor smoking history on kidney transplant recipient outcomes is undefined.

METHODS

We systematically searched, critically appraised, and summarized associations between donor smoking and primary outcomes of death-censored and all-cause graft failure (DCGF, ACGF), and secondary outcomes of allograft histology, delayed graft function, serum creatinine, estimated glomerular filtration rate, and mortality. We searched MEDLINE, Embase, and Cochrane Databases from 2000 to 2023. Risk of bias was assessed using Risk of Bias in Non-randomized Studies - of Exposure tool. Quality of evidence was assessed by Grading of Recommendations Assessment, Development and Evaluation Working Group recommendations. We pooled results using inverse variance, random-effects model and reported hazard ratios for time-to-event outcomes or binomial proportions. Statistical heterogeneity was assessed with I2 statistic.

RESULTS

From 1785 citations, we included 17 studies. Donor smoking was associated with modestly increased DCGF (HR 1.05 (95% CI: 1.01, 1.09); I2 = 0%; low quality of evidence), predominantly in deceased donors, and ACGF in adjusted analyses (HR 1.12 (95% CI: 1.06, 1.19); I2 = 20%; very low quality of evidence). Other outcomes could not be pooled meaningfully.

CONCLUSIONS

Kidney donor smoking history was associated with modestly increased risk of death-censored graft failure and all-cause graft failure. This review emphasizes the need for further research, standardized reporting, and thoughtful consideration of donor factors like smoking in clinical decision-making on kidney utilization and allocation.

APOL1 Kidney Risk Variants and Long-Term Kidney Function in Healthy Middle-Aged Black Individuals: The Atherosclerosis Risk in Communities (ARIC) Study

Rationale & Objective

The effect of apolipoprotein L1(APOL1) genotype on future risk of kidney disease among middle-aged individuals with good kidney function is not well established.

Study Design

Longitudinal cohort study.

Setting & Participants

In total, 5,886 healthy individuals (45-64 years old) enrolled in the Atherosclerosis Risk in Communities study with creatinine-based estimated glomerular filtration rate ≥ 80 mL/min who would be suitable kidney donors.

Exposures

Race and APOL1 genotype.

Outcomes

Creatinine- and cystatin C-based estimated glomerular filtration rate (eGFRcr-cys) using the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) 2021 equation, urinary albumin-creatinine ratio (UACR), proportion with chronic kidney disease (CKD) 3a or worse, end-stage kidney disease (ESKD), and death.

Analytical Approach

Participants grouped based on race and APOL1 genotype. Compared eGFRcr-cys and UACR across groups. Multinomial logistic regression models were used compare odds of CKD. Kaplan-Meier survival curves were created to compare rates of ESKD and death at last follow-up.

Results

There were 5,075 Whites (86%), 701 Blacks carrying the low-risk APOL1 genotype (12%), and 110 Blacks carrying the high-risk APOL1 genotype (2%). The mean age at baseline was 53 ± 6 years. At 10 years, White participants had lower eGFRcr-cys than low-risk and high-risk groups (89 ± 16 vs 91 ± 16 and 92 ± 15 mL/min/1.73 m2, respectively; P < 0.001). At 25 years, White participants continued to have lower eGFRcr-cys than the low-risk group (70 ± 18 vs 72 ± 19 mL/min/1.73 m2; P < 0.001) but not compared with the high-risk APOL1 genotype (67±23 mL/min/1.73 m2). There was no difference in UACR among groups at 10 and 25 years (P = 0.87 and 0.91, respectively). The odds of developing CKD stage 3a or worse were not different between low-risk and high-risk APOL1 group in both unadjusted and adjusted models (P = 0.26 and P = 0.39, respectively). At last follow-up, <5% developed ESKD, and 45% of individuals either died or reached ESKD with no difference in outcomes between the groups.

Limitations

Low ascertainment because of death and long follow-up.

Conclusions

Among middle-aged individuals, APOL1 genotype does not appear to be a major driver of future risk of kidney disease.

Bariatric surgery in prospective obese living kidney donors: scoping review and management decision algorithm

INTRODUCTION

Global chronic kidney disease is now epidemic, with substantial health and economic consequences. While scientific support for living donor renal transplants (LDRT) is strong, donor shortages necessitate consideration of expanded criteria, including obese individuals. Bariatric surgery (BS) may mitigate obesity-related risks, but research on living donor candidates is scarce. Our scoping review aims to compile evidence, identify gaps, and formulate an algorithm to guide healthcare professionals in evaluating BS for obese living donors.

EVIDENCE ACQUISITION

We did a systematic search of studies on living kidney donors and obesity. We searched the MEDLINE Ovid, Embase Ovid, CENTRAL and Web of Science databases for studies from database inception to March 30, 2023. All English-language articles available in full text have been considered. Excluded are commentaries, editorials, letters, and abstracts.

EVIDENCE SYNTHESIS

Obesity in LDRT raises long-term ESRD risk. Current high BMI donor admission raises ethical and clinical concerns. Encouraging timely weight loss can make obese candidates suitable donors, reducing risks. Sleeve gastrectomy is the most reported and preferable approach, since it minimizes hyperoxaluria risk. Re-evaluation for donation is possible 6-12 months post-BS, with BMI<35 for three months. Cost-benefit analysis favors BS over nephrectomy in obese donors (cost-benefit ratio: 3.64) when graft survival is equal.

CONCLUSIONS

BS shows promise with short-term effectiveness and potential long-term outcomes. However, it should not be perceived as a means to expand the donor pool but rather as a personalized approach to address obesity and improve individuals' health.

Fracture Risk Among Living Kidney Donors 25 Years After Donation

Importance

Living kidney donors may have an increased risk of fractures due to reductions in kidney mass, lower concentrations of serum 1,25-dihydroxyvitamin D, and secondary increases in serum parathyroid hormone.

Objective

To compare the overall and site-specific risk of fractures among living kidney donors with strictly matched controls from the general population who would have been eligible to donate a kidney but did not do so.

Design, Setting, and Participants

This survey study was conducted between December 1, 2021, and July 31, 2023. A total of 5065 living kidney donors from 3 large transplant centers in Minnesota were invited to complete a survey about their bone health and history of fractures, and 16 156 population-based nondonor controls without a history of comorbidities that would have precluded kidney donation were identified from the Rochester Epidemiology Project and completed the same survey. A total of 2132 living kidney donors and 2014 nondonor controls responded to the survey. Statistical analyses were performed from May to August 2023.

Exposure

Living kidney donation.

Main Outcomes and Measures

The rates of overall and site-specific fractures were compared between living kidney donors and controls using standardized incidence ratios (SIRs).

Results

At the time of survey, the 2132 living kidney donors had a mean (SD) age of 67.1 (8.9) years and included 1245 women (58.4%), and the 2014 controls had a mean (SD) age of 68.6 (7.9) years and included 1140 women (56.6%). The mean (SD) time between donation or index date and survey date was 24.2 (10.4) years for donors and 27.6 (10.7) years for controls. The overall rate of fractures among living kidney donors was significantly lower than among controls (SIR, 0.89; 95% CI, 0.81-0.97). However, there were significantly more vertebral fractures among living kidney donors than among controls (SIR, 1.42; 95% CI, 1.05-1.83).

Conclusions and Relevance

This survey study found a reduced rate of overall fractures but an excess of vertebral fractures among living kidney donors compared with controls after a mean follow-up of 25 years. Treatment of excess vertebral fractures with dietary supplements such as vitamin D3 may reduce the numbers of vertebral fractures and patient morbidity.

Performance of estimated glomerular filtration rate equations in Black living kidney donor candidates

INTRODUCTION

New estimated glomerular filtration rate (eGFR) equations using serum creatinine and/or cystatin C have been derived to eliminate adjustment by perceived Black ancestry. We sought to analyze the performance of newer eGFR equations among Black living kidney donor candidates.

METHODS

Black candidates (n = 64) who had measured iothalamate GFR between January 2015 and October 2021 were included, and eGFR was calculated using race adjusted (eGFRcr2009 and eGFRcr-cys2012) and race unadjusted (eGFRcys2012, eGFRcr2021, and eGFRcr-cys2021) CKD-EPI equations. Bias and accuracy were calculated.

RESULTS

The eGFRcr2021 equation had a negative bias of 9 mL/min/1.73 m2 , while other equations showed a modest positive bias. Accuracy within 10% and 30% was greatest using the eGFRcr-cys2021 equation. With the eGFRcr2021 equation, 9.4% of donors with an mGFR > 80 mL/min/1.73 m2 were misclassified as having an eGFR < 80 mL/min/1.73 m2 . eGFR was also compared among 18 kidney donors at 6-24 months post-donation. Post-donation, the percentage of donors with an eGFR < 60 mL/min/1.73 m2 was 44% using the eGFRcr2021 equation compared to 11% using the eGFRcr-cys2021 equation.

CONCLUSION

The CKD-EPICr2021 equation appears to underestimate true GFR in Black living donor candidates. Alternatively, compared to CKD-EPICr2021, the CKD-EPICr-CysC2021 equation appears to perform with less bias and improved accuracy.

Clinical relevance of the living kidney donor profile index in Korean kidney transplant recipients

BACKGROUND

The Living Kidney Donor Profile Index (LKDPI) was developed in the United States to predict graft outcomes based on donor characteristics. However, there are significant differences in donor demographics, access to transplantation, proportion of ABO incompatibility, and posttransplant mortality in Asian countries compared with the United States.

METHODS

We evaluated the clinical relevance of the LKDPI score in a Korean kidney transplant cohort by analyzing 1860 patients who underwent kidney transplantation between 2000 and 2019. Patients were divided into three groups according to LKDPI score: <0, 1-19.9, and ≥20.

RESULTS

During a median follow-up of 119 months, 232 recipients (12.5%) experienced death-censored graft loss, and 98 recipients (5.3%) died. High LKDPI scores were significantly associated with increased risk of death-censored graft loss independent of recipient characteristics (LKDPI 1-19.9: HR 1.389, 95% CI 1.036-1.863; LKDPI ≥20: HR 2.121, 95% CI 1.50-2.998). High LKDPI score was also significantly associated with increased risk of biopsy-proven acute rejection and impaired graft renal function. By contrast, overall patient survival rates were comparable among the LKDPI groups.

CONCLUSION

High LKDPI scores were associated with an increased risk of death-censored graft loss, biopsy-proven acute rejection, and impaired graft renal function among a Korean kidney transplant cohort.

Risk factors for lower renal compensation after nephrectomy: an analysis of living kidney donors in an Amazonian cohort

INTRODUCTION

Living donor kidney transplantation is considered the ideal renal replacement therapy because it has a lower complication rate and allows an efficient response to the high demand for grafts in the healthcare system. Careful selection and adequate monitoring of donors is a key element in transplantation. Individuals at greater risk of developing kidney dysfunction after nephrectomy must be identified.

OBJECTIVE

To identify risk factors associated with a renal compensation rate (CR) below 70% 12 months after nephrectomy.

METHODS

This observational retrospective longitudinal study included living kidney donors followed up at the Lower Amazon Regional Hospital between 2016 and 2022. Data related to sociodemographic variables, comorbid conditions and kidney function parameters were collected.

RESULTS

The study enrolled 32 patients. Fourteen (43.75%) had a CR < 70% 12 months after kidney donation. Logistic regression found obesity (Odds Ratio [95%CI]: 10.6 [1.7-65.2]), albuminuria (Odds Ratio [95%CI]: 2.41 [1.2-4.84]) and proteinuria (Odds Ratio [95%CI]: 1.14 [1.03-1.25]) as risk factors. Glomerular filtration rate was a protective factor (Odds Ratio [95% CI]: 0.92 [0.85-0.99]).

CONCLUSION

Obesity, albuminuria and proteinuria adversely affected short-term renal compensation rate. Further studies are needed to uncover the prognostic implications tied to these risk factors. Our findings also supported the need for careful individualized assessment of potential donors and closer monitoring of individuals at higher risk.

Racial Equity in Living Donor Kidney Transplant Centers, 2008-2018

Importance

It is unclear whether center-level factors are associated with racial equity in living donor kidney transplant (LDKT).

Objective

To evaluate center-level factors and racial equity in LDKT during an 11-year time period.

Design, Setting, and Participants

A retrospective cohort longitudinal study was completed in February 2023, of US transplant centers with at least 12 annual LDKTs from January 1, 2008, to December 31, 2018, identified in the Health Resources Services Administration database and linked to the US Renal Data System and the Scientific Registry of Transplant Recipients.

Main Outcomes and Measures

Observed and model-based estimated Black-White mean LDKT rate ratios (RRs), where an RR of 1 indicates racial equity and values less than 1 indicate a lower rate of LDKT of Black patients compared with White patients. Estimated yearly best-case center-specific LDKT RRs between Black and White individuals, where modifiable center characteristics were set to values that would facilitate access to LDKT.

Results

The final cohorts of patients included 394 625 waitlisted adults, of whom 33.1% were Black and 66.9% were White, and 57 222 adult LDKT recipients, of whom 14.1% were Black and 85.9% were White. Among 89 transplant centers, estimated yearly center-level RRs between Black and White individuals accounting for center and population characteristics ranged from 0.0557 in 2008 to 0.771 in 2018. The yearly median RRs ranged from 0.216 in 2016 to 0.285 in 2010. Model-based estimations for the hypothetical best-case scenario resulted in little change in the minimum RR (from 0.0557 to 0.0549), but a greater positive shift in the maximum RR from 0.771 to 0.895. Relative to the observed 582 LDKT in Black patients and 3837 in White patients, the 2018 hypothetical model estimated an increase of 423 (a 72.7% increase) LDKTs for Black patients and of 1838 (a 47.9% increase) LDKTs for White patients.

Conclusions and Relevance

In this cohort study of patients with kidney failure, no substantial improvement occurred over time either in the observed or the covariate-adjusted estimated RRs. Under the best-case hypothetical estimations, modifying centers' participation in the paired exchange and voucher programs and increased access to public insurance may contribute to improved racial equity in LDKT. Additional work is needed to identify center-level and program-specific strategies to improve racial equity in access to LDKT.

Transplant Nephrologists' Preferences for Clinical Decision Support for APOL1 Genetic Testing of Living Kidney Donors: A Focus Group Study

Key Points

Opportunities exist for clinical decision support (CDS) to help transplant nephrologists counsel living donors receiving apolipoprotein L1 (APOL1 ) genetic test results. CDS for APOL1 genetic test results should provide access to patient education materials and reminders at follow-up appointments. Optimal APOL1 CDS would notify providers when results are available, provide information on follow-up appointments, and provide access to patient education materials.

Podcast

This article contains a podcast at https://dts.podtrac.com/redirect.mp3/www.asn-online.org/media/podcast/K360/2023_12_01_KID0000000000000265.mp3

Time to Change Our Viewpoints to Assess Renal Risks in Patients with Solitary Kidneys beyond Traditional Approaches?

Solitary functioning kidney (SFK) can be defined as the absence or hypofunction of a kidney due to acquired or congenital reasons. A congenital solitary functioning kidney (cSFK) is more common than is an acquired one (aSFK) and is characterized by the anatomical absence (agenesis) or hypofunction (hypoplasia; hypodysplasia) of one kidney from birth. Among the acquired causes, the most important is nephrectomy (Nx) (due to the donor, trauma or mass resection). Patients with SFK are at risk for the development of chronic kidney disease (CKD) in the long term. This risk potential is also significantly affected by hypertension. The relationship between hypertension and subclinical chronic inflammation is a connection that has not yet been fully clarified pathogenetically, but there are many studies highlighting this association. In recent years, studies examining different fibrosis and inflammation biomarkers in terms of the evaluation and prediction of renal risks have become increasingly popular in the literature. Oxidative stress is known to play an important role in homocysteine-induced endothelial dysfunction and has been associated with hypertension. In our study, we aimed to investigate the relationship between ambulatory blood pressure monitoring (ABPM) and urinary/serum fibrosis and inflammatory markers in patients with SFK. We prospectively investigated the relationship between ABPM results and soluble urokinase plasminogen activator receptor (suPAR), procollagen type III N-terminal peptide (PIIINP), homocysteine and other variables in 85 patients with SFK and compared them between cSFK and aSFK groups. In the etiology of SFK, a congenital or acquired origin may differ in terms of the significance of biomarkers. In particular, the serum homocysteine level may be associated with different clinical outcomes in patients with cSFK and aSFK.

High RIPK3 expression is associated with a higher risk of early kidney transplant failure

Renal ischemia-reperfusion injury (IRI) is associated with reduced allograft survival, and each additional hour of cold ischemia time increases the risk of graft failure and mortality following renal transplantation. Receptor-interacting protein kinase 3 (RIPK3) is a key effector of necroptosis, a regulated form of cell death. Here, we evaluate the first-in-human RIPK3 expression dataset following IRI in kidney transplantation. The primary analysis included 374 baseline biopsy samples obtained from renal allografts 10 minutes after onset of reperfusion. RIPK3 was primarily detected in proximal tubular cells and distal tubular cells, both of which are affected by IRI. Time-to-event analysis revealed that high RIPK3 expression is associated with a significantly higher risk of one-year transplant failure and prognostic for one-year (death-censored) transplant failure independent of donor and recipient associated risk factors in multivariable analyses. The RIPK3 score also correlated with deceased donation, cold ischemia time and the extent of tubular injury.

Chronic Kidney Disease Risk in Living Kidney Transplant Donors: A Long-Term Follow-Up Study

BACKGROUND

Living kidney donors (LKD) may experience some untoward consequences following donation such as development of chronic kidney disease (CKD). In this study, we aimed to investigate the rate of development of CKD and factors affecting the development of CKD in LKDs during long-term follow-up from a center in Turkey.

METHODS

This study was a retrospective analysis of LKDs followed between January 2000 and December 2017. Pre-transplant and post-transplant clinical data of the 338 LKDs were recorded and compared. Factors affecting the development of stage 3 and later stages of CKD were analyzed.

RESULTS

Majority of the donors were females (64.2%), and the median age of all donors was 47 (39-54) years. Stage 3 CKD developed in 50 donors during the median follow-up of 71 months. Older age at the time of transplantation and a low pre-transplant estimated glomerular filtration rate (eGFR) were determined as the factors affecting the development of stage 3 CKD (p < 0.001, p < 0.001). The receiver operating characteristic analysis showed that the cut-off age for the development of stage 3 CKD was 50.5 years. Newly diagnosed hypertension was detected in 57 patients (16.8%) after the transplantation. While hypertension was seen at a rate of 42% in those with an eGFR <60 mL/min/1.73 m2, it was detected at 19.4% in the group with an eGFR >60 mL/min/1.73 m2 (p < 0.001).

CONCLUSION

These results reveal that being a LKD is associated with the development of CKD and hypertension. Age and eGFR values at the time of transplantation were the determinants for the development of CKD.

How the websites of high-volume US centers address the risks of living kidney donation

BACKGROUND

The websites of US transplant centers may be a source of information about the renal risks of potential living kidney donors.

METHODS

To include only likely best practices, we surveyed websites of centers that performed at least 50 living donor kidney transplants per year. We tabulated how risks were conveyed regarding loss of eGFR at donation, the adequacy of long-term ESRD risk data, long-term donor mortality, minority donor ESRD risk, concerns about hyperfiltration injury versus the risk of end-stage kidney diseases, comparisons of ESRD risks in donors to population risks, the increased risks of younger donors, an effect of the donation itself to increase risk, quantifying risks over specific intervals, and a lengthening list of small post-donation medical risks and metabolic changes of uncertain significance.

RESULTS

While websites had no formal obligation to address donor risks, many offered abundant information. Some conveyed OPTN-mandated requirements for counseling individual donor candidates. While actual wording often varied, there was general agreement on many issues. We occasionally noted clear-cut differences among websites in risk characterization and other outliers.

CONCLUSIONS

The websites of the most active US centers offer insights into how transplant professionals view living kidney donor risk. Website content may merit further study.

External Validation of Toulouse-Rangueil eGFR12 Prediction Model After Living Donor Nephrectomy

Decreased postdonation eGFR is associated with a higher risk of ESRD after living kidney donation, even when accounting for predonation characteristics. The Toulouse-Rangueil model (TRM) estimates 12 month postdonation eGFR (eGFR12) to inform counseling of candidates for living donation. The TRM was validated in several single-center European cohorts but has not been validated in US donors. We assessed the TRM in living kidney donors in the US using SRTR data 1/2000-6/2021. We compared the 2021 CKD-EPI equation eGFR12 observed estimates to the TRM eGFR12 predictions. Median (IQR) bias was -3.4 (-9.3, 3.4) mL/min/1.73 m2. Bias was higher for males vs. females (bias [IQR] -4.4 [-9.9, 1.8] vs. -2.9 [-8.8, 4.1]) and younger (31-40) vs. older donors (>50) (bias -4.9 [-10.6, 3.0] vs. -2.1 [-7.5, 4.0]). Bias was also larger for Black vs. White donors (bias (-6.7 [-12.1, -0.3], p < 0.001) vs. (-3.4 [-9.1, 3.1], p < 0.001)). Overall correlation was 0.71. In a sensitivity analysis using the 2009 CKD-EPI equation, results were generally consistent with exception to a higher overall bias (bias -4.2 [-9.8, 2.4]). The TRM overestimates postdonation renal function among US donors. Overestimation was greatest for those at higher risk for postdonation ESRD including male, Black, and younger donors. A new equation is needed to estimate postdonation renal function.

The relationship of peritubular capillary density with glomerular volume and kidney function in living kidney donors

BACKGROUND

Peritubular capillary rarefaction plays an important role in the progression of chronic kidney disease. Little is known about the relation between peritubular capillary density, glomerular volume and filtration rate in the healthy kidney.

METHODS

In this single-center study, we included 69 living kidney donors who donated between 2005 and 2008 and had representative renal biopsies available. In all donors, glomerular filtration rate was measured using 125I-Iothalamate before donation and at five years after donation. Before donation, the increase in glomerular filtration rate after dopamine stimulation was measured. Glomerular volume and peritubular capillary density were determined in biopsies taken at the time of transplantation. Pearson's correlation coefficient and linear regression were used to assess relations between parameters.

RESULTS

Mean donor age was 52 ± 11 years and mean measured glomerular filtration rate was 119 ± 22 mL/min before donation and 82 ± 15 mL/min at five years after donation. While peritubular capillary density (measured by either number of peritubular capillaries/50,000 μm2 or number of peritubular capillaries/tubule) was not associated with measured glomerular filtration rate before or after donation, number of peritubular capillaries/tubule was associated with the increase in measured glomerular filtration rate after dopamine stimulation (St.β = 0.33, p = 0.004), and correlated positively with glomerular volume (R = 0.24, p = 0.047). Glomerular volume was associated with unstimulated measured glomerular filtration rate before donation (St.β = 0.31, p = 0.01) and at five years (St.β = 0.30, p = 0.01) after donation, independent of age.

CONCLUSIONS

In summary, peritubular capillary density was not related to unstimulated kidney function before or after kidney donation, in contrast to glomerular volume. However, number of peritubular capillaries/tubule correlated with the increase in glomerular filtration rate after dopamine stimulation in healthy kidneys, and with glomerular volume. These findings suggest that peritubular capillary density and glomerular volume differentially affect kidney function in healthy living kidney donors.

Impact of Particulate Matter With an Aerodynamic Diameter <2.5 μm Concentration on Postoperative Renal Function in Living Kidney Donors

BACKGROUND

Ambient air pollution has become 1 of the most important public health issues worldwide. In particular, particulate matter with an aerodynamic diameter <2.5 μm (PM2.5) is a fatal component of air pollution. We aimed to analyze whether perioperative exposure to PM2.5 is associated with the deterioration of renal function in living kidney donors.

METHODS

This study was conducted on 232 kidney donors with postoperative 2-year glomerular filtration rate (GFR). The GFR was determined by serum creatinine-based method using the Modification of Diet in Renal Disease equation and radionuclide-based method using 99mTc-DTPA renal scintigraphy. Perioperative exposure to PM2.5 was calculated using data from the AIRKOREA System. Multiple linear and logistic regression analyses were performed to estimate the associations between mean PM2.5 concentration and postoperative 2-year GFR.

RESULTS

Postoperative Modification of Diet in Renal Disease-estimated GFRs of kidney donors with low PM2.5 concentrations were significantly higher than those of those with high PM2.5 concentrations. A 1-μg/m3 increase in mean PM2.5 concentration was associated with decreased GFR by 0.20 mL/min/1.73 m2. In addition, a 1-μg/m3 increase in mean PM2.5 concentration was associated with an 11% increased risk of chronic kidney disease stage ≥3 at 2 years after donor nephrectomy.

CONCLUSION

In patients who underwent donor nephrectomy, exposure to PM2.5 negatively affects renal function and is positively associated with the prevalence of chronic kidney disease.

Measured Glomerular Filtration Rate in Live Related Kidney Donors Three Months Post-Kidney Donation: A Single-Center Experience From Western India

Background Glomerular filtration rate (GFR) estimation is pivotal in the evaluation of kidney donors. There are various methods available for assessing GFR, but there has been a lack of consensus on the measurement of GFR and the frequency of renal evaluation after kidney donation. Our study aims to analyze the measured GFR (m-GFR) before and three months after kidney donation and note the compensatory abilities of the remnant kidney in live related kidney donors. Methods This prospective observational study was conducted at the Department of Nephrology, Dr. D. Y. Patil Medical College, Hospital & Research Centre, Pune, from April 2021 to December 2022. The study included 30 donors from both genders aged between 23 and 73 years. The measured GFR was calculated using a technetium-99m diethylene triamine pentaacetic acid (Tc-99m DTPA) scan. We analyzed donor characteristics and various parameters that included demography, anthropometry, blood pressure, and serum creatinine and measured GFR (m-GFR) using a Tc-99m DTPA scan, which was compared before and three months after donor nephrectomy. Results Of the 30 donors, 25 (83.3%) were females and five (16.7%) were males. The mean age of donors was 49.23 ± 12.29 years. The mean body mass index (BMI) was noted to be 24.73 ± 5.58 kg/m2, whereas the mean body surface area (BSA) was 1.59 ± 0.12 m2. In terms of the measured GFR by DTPA scan, pre-donation and post-donation, the average GFR for our population was 103.83 ± 10.07 mL/minute/1.73 m2 and 60.47±6.57 mL/minute/1.73 m2, respectively. The mean measured GFR of remnant kidney increased by 9.21 ± 4.39 mL/minute/1.73 m2 in 28 donors, while two donors had a fall in the mean measured GFR by 6.8 ± 1.69 mL/minute/1.73 m2. Conclusions To safeguard donor health, accurate measurement of GFR at various timelines after kidney donation should be considered as there are various limitations associated with the use of serum creatinine-based GFR estimating equations for solitary kidneys. However, long-term studies are required to analyze the changes in GFR after nephrectomy and determine the adequacy of compensatory changes in the remnant kidney post-kidney donation.

Medical-ethical guidelines: Living donation of solid organs

No abstract available.

Living kidney donors with HIV: experience and outcomes from a case series by the HOPE in Action Consortium

Background

Living kidney donation is possible for people living with HIV (PLWH) in the United States within research studies under the HIV Organ Policy Equity (HOPE) Act. There are concerns that donor nephrectomy may have an increased risk of end-stage renal disease (ESRD) in PLWH due to HIV-associated kidney disease and antiretroviral therapy (ART) nephrotoxicity. Here we report the first 3 cases of living kidney donors with HIV under the HOPE Act in the United States.

Methods

Within the HOPE in Action Multicenter Consortium, we conducted a prospective study of living kidney donors with HIV. Pre-donation, we estimated the 9-year cumulative incidence of ESRD, performed genetic testing of apolipoprotein L1 (APOL1), excluding individuals with high-risk variants, and performed pre-donation kidney biopsies (HOPE Act requirement). The primary endpoint was ≥grade 3 nephrectomy-related adverse events (AEs) in year one. Post-donation, we monitored glomerular filtration rate (measured by iohexol/Tc-99m DTPA [mGFR] or estimated with serum creatinine [eGFR]), HIV RNA, CD4 count, and ART.

Findings

There were three donors with two-four years of follow-up: a 35 year-old female, a 52 year-old male, and a 47 year-old male. Pre-donation 9-year estimated cumulative incidence of ESRD was 3.01, 8.01, and 7.76 per 10,000 persons, respectively. In two donors with APOL1 testing, no high-risk variants were detected. Biopsies from all three donors showed no kidney disease. Post-donation, two donors developed nephrectomy-related ≥grade 3 AEs: a medically-managed ileus and a laparoscopically-repaired incisional hernia. GFR declined from 103 to 84 mL/min/1.73 m2 at four years (mGFR) in donor 1, from 77 to 52 mL/min/1.73 m2 at three years (eGFR) in donor 2, and from 65 to 39 mL/min/1.73 m2 at two years (eGFR) in donor 3. HIV RNA remained <20 copies/mL and CD4 count remained stable in all donors.

Interpretation

The first three living kidney donors with HIV under the HOPE Act in the United States have had promising outcomes at two-four years, providing proof-of-concept to support living donation from PLWH to recipients with HIV.

Funding

National Institute of Allergy and Infectious Diseases, National Institutes of Health.

Prediction tool for renal adaptation after living kidney donation using interpretable machine learning

Introduction

Post-donation renal outcomes are a crucial issue for living kidney donors considering young donors' high life expectancy and elderly donors' comorbidities that affect kidney function. We developed a prediction model for renal adaptation after living kidney donation using interpretable machine learning.

Methods

The study included 823 living kidney donors who underwent nephrectomy in 2009-2020. AutoScore, a machine learning-based score generator, was used to develop a prediction model. Fair and good renal adaptation were defined as post-donation estimated glomerular filtration rate (eGFR) of ≥ 60 mL/min/1.73 m² and ≥ 65% of the pre-donation values, respectively.

Results

The mean age was 45.2 years; 51.6% were female. The model included pre-donation demographic and laboratory variables, GFR measured by diethylenetriamine pentaacetate scan, and computed tomography kidney volume/body weight of both kidneys and the remaining kidney. The areas under the receiver operating characteristic curve were 0.846 (95% confidence interval, 0.762-0.930) and 0.626 (0.541-0.712), while the areas under the precision-recall curve were 0.965 (0.944-0.978) and 0.709 (0.647-0.788) for fair and good renal adaptation, respectively. An interactive clinical decision support system was developed.

Conclusion

The prediction tool for post-donation renal adaptation showed good predictive capability and may help clinical decisions through an easy-to-use web-based application.

Comparison of Three Glomerular Filtration Rate Estimating Equations with 24-Hour Urine Creatinine Clearance Measurement in Potential Living Kidney Donors

Background

The accuracy of the measurement of renal function in potential living kidney donors (PLKD) is essential. The direct measurement of glomerular filtration rate (mGFR) has been considered the "gold standard." The estimated GFR (eGFR) with 24-hour urinary creatinine clearance (CrCl) is frequently used because of its availability. We aim to evaluate the correlation and agreement of eGFR using serum-based creatinine formulas (Cockcroft-Gault, MDRD, and CKD-EPI) and the eGFR based on 24-hour urinary CrCl to evaluate kidney function in PLKD.

Methods

We evaluated the kidney function in 799 PLKD using 24-hour urinary CrCl method and compared the correlation and agreement with the eGFR based on creatinine formulas (Cockcroft-Gault, MDRD, and CKD-EPI). We calculated the mean bias (difference), precision (SD of this difference), accuracy, and performed Bland-Altman plots.

Results

A total of 799 PLKD were analyzed. The age of the PLKD ranged from 18 to 73 years. Weak to mild correlation was observed between 24-hour urinary CrCl and all formulas (ranged from 0.31 to 0.49). The three equations underestimated the GFR. Using the Bland-Altman graphic, we observed that the CKD-EPI was the least scattered and most precise; however, mean bias and the interval range (limits of agreement) of all formulas were too big to assume equivalence between 24-hour urinary CrCl method and eGFR based on creatinine. Results of mean bias were similar when comparing the three equations in patients with CrCl GFR <60. However, the accuracy of all formulas was better for the female group and the youngest individuals (≤40 years old).

Conclusion

In this PLKD cohort, of all the three equations, the CKD-EPI was the least scattered and most precise. However, the correlation and the level of agreement between the three equations and 24-hour urinary CrCl were too low to assume the equivalence.

Development and Validation of a Hypertension Risk Calculator for Living Kidney Donors

BACKGROUND

Ideally, when deciding whether to donate, kidney donor candidates would understand their long-term risks. Using single-center data (N = 4055; median [quartiles] follow-up: 18 [9-28] y), we developed a calculator for postdonation hypertension and validated it using long-term data from an external single-center cohort (N = 1189, median [quartiles] follow-up: 9 [5-17] y).

METHODS

Risk factors considered were routinely obtained at evaluation from donor candidates. Two modeling approaches were evaluated: Cox proportional hazards and random survival forest models. Cross-validation prediction error and Harrell's concordance-index were used to compare accuracy for model development. Top-performing models were assessed in the validation cohort using the concordance-index and net reclassification improvement.

RESULTS

In the development cohort, 34% reported hypertension at a median (quartiles) of 16 (8-24) y postdonation; and in the validation cohort, 29% reported hypertension after 17 (10-22) y postdonation. The most accurate model was a Cox proportional hazards model with age, sex, race, estimated glomerular filtration rate, systolic and diastolic blood pressure, body mass index, glucose, smoking history, family history of hypertension, relationship with recipient, and hyperlipidemia (concordance-index, 0.72 in the development cohort and 0.82 in the validation cohort).

CONCLUSIONS

A postdonation hypertension calculator was developed and validated; it provides kidney donor candidates, their family, and care team a long-term projection of hypertension risk that can be incorporated into the informed consent process.

Genetic evaluation of living kidney donor candidates: A review and recommendations for best practices

The growing accessibility and falling costs of genetic sequencing techniques has expanded the utilization of genetic testing in clinical practice. For living kidney donation, genetic evaluation has been increasingly used to identify genetic kidney disease in potential candidates, especially in those of younger ages. However, genetic testing on asymptomatic living kidney donors remains fraught with many challenges and uncertainties. Not all transplant practitioners are aware of the limitations of genetic testing, are comfortable with selecting testing methods, comprehending test results, or providing counsel, and many do not have access to a renal genetic counselor or a clinical geneticist. Although genetic testing can be a valuable tool in living kidney donor evaluation, its overall benefit in donor evaluation has not been demonstrated and it can also lead to confusion, inappropriate donor exclusion, or misleading reassurance. Until more published data become available, this practice resource should provide guidance for centers and transplant practitioners on the responsible use of genetic testing in the evaluation of living kidney donor candidates.

Association of Pre- and Post-Donation Renal Function with Midterm Estimated Glomerular Filtration Rate in Living Kidney Donors: A Retrospective Study

PURPOSE

The estimated glomerular filtration rate (eGFR) at 6 months after donation (eGFR_6m) is strongly associated with the risk of end-stage renal disease in living kidney donors. This study aimed to investigate the incidence of eGFR_6m <60 mL/min/1.73 m² (eGFR_6m <60) and identify the risk factors that can predict the occurrence of eGFR_6m <60 in living kidney donors.

MATERIALS AND METHODS

Living kidney donors who underwent nephrectomy at Severance Hospital between January 2009 and December 2019 were identified. We excluded 94 of 1233 donors whose creatinine values at 6 months after donation were missing. The risk factors for eGFR_6m <60 were assessed using multivariate regression analysis. The optimal cutoff points for candidate risk factors for predicting eGFR_6m <60 occurrence were determined using the Youden index.

RESULTS

The eGFR_6m <60 occurred in 17.3% of the participants. Older age (≥44 years), history of hypertension, lower preoperative eGFR (<101 mL/min/1.73 m²), and degree of increase in creatinine levels on postoperative day 2 compared to those before surgery (ΔCr2_pre) (≥0.39 mg/dL) increased the risk of eGFR_6m <60. The addition of ΔCr2_pre to preoperative eGFR yielded a higher predictive accuracy for predicting eGFR_6m <60 than that with preoperative eGFR alone {area under the receiver operating characteristic curve=0.886 [95% confidence interval (CI), 0.863-0.908] vs. 0.862 (95% CI, 0.838-0.887), p<0.001}.

CONCLUSION

The incidence of eGFR_6m <60 was 17.3%. Older age, lower preoperative eGFR, history of hypertension, and greater ΔCr2_pre were associated with the occurrence of eGFR_6m <60 after living donor nephrectomy. The combination of preoperative eGFR and ΔCr2_pre showed the highest predictive power for eGFR_6m <60.

Renal Vessel Extension With Cryopreserved Vascular Grafts: Overcoming Surgical Pitfalls in Living Donor Kidney Transplant

In LDKT, right kidneys and kidneys with anomalous vascularization are often deferred because of concerns on complications and vascular reconstructions. To date, only few reports have examined renal vessel extension with cryopreserved vascular grafts in LDKT. The aim of this study is to investigate the effect of renal vessel extension on short-term outcomes and ischemia times in LDKT. From 2012 to 2020, recipients of LDKT with renal vessels extension were compared with standard LDKT recipients. Subset analysis of rights grafts and grafts with anomalous vascularization, with or without renal vessel extension, was performed. Recipients of LDKT with (n = 54) and without (n = 91) vascular extension experienced similar hospital stays, surgical complications and DGF rates. For grafts with multiple vessels, renal vessel extension granted a faster implantation time (44±5 vs. 72±14 min), which resulted comparable to that of standard anatomy grafts. Right kidney grafts with vascular extension had a faster implantation time compared to right kidney grafts without vascular lengthening (43±5 vs. 58±9 min), and a comparable implantation time to left kidney grafts. Renal vessel extension with cryopreserved vascular grafts allows faster implantation time in right kidney grafts or grafts with anomalous vascularization, maintaining similar surgical and functional outcomes.

Prediction of measured GFR after living kidney donation from pre-donation parameters

BACKGROUND

One of the challenges in living kidney donor screening is to estimate remaining kidney function after donation. Here we developed a new model to predict post-donation measured glomerular filtration rate (mGFR) from pre-donation serum creatinine, age and sex.

METHODS

In the prospective development cohort (TransplantLines, n = 511), several prediction models were constructed and tested for accuracy, precision and predictive capacity for short- and long-term post-donation 125I-iothalamate mGFR. The model with optimal performance was further tested in specific high-risk subgroups (pre-donation eGFR <90 mL/min/1.73 m2, a declining 5-year post-donation mGFR slope or age >65 years) and validated in internal (n = 509) and external (Mayo Clinic, n = 1087) cohorts.

RESULTS

In the development cohort, pre-donation estimated GFR (eGFR) was 86 ± 14 mL/min/1.73 m2 and post-donation mGFR was 64 ± 11 mL/min/1.73 m2. Donors with a pre-donation eGFR ≥90 mL/min/1.73 m2 (present in 43%) had a mean post-donation mGFR of 69 ± 10 mL/min/1.73 m2 and 5% of these donors reached an mGFR <55 mL/min/1.73 m2. A model using pre-donation serum creatinine, age and sex performed optimally, predicting mGFR with good accuracy (mean bias 2.56 mL/min/1.73 m2, R2 = 0.29, root mean square error = 11.61) and precision [bias interquartile range (IQR) 14 mL/min/1.73 m2] in the external validation cohort. This model also performed well in donors with pre-donation eGFR <90 mL/min/1.73 m2 [bias 0.35 mL/min/1.73 m2 (IQR 10)], in donors with a negative post-donation mGFR slope [bias 4.75 mL/min/1.73 m2 (IQR 13)] and in donors >65 years of age [bias 0.003 mL/min/1.73 m2 (IQR 9)].

CONCLUSIONS

We developed a novel post-donation mGFR prediction model based on pre-donation serum creatinine, age and sex.

Living kidney donor evaluation is associated with early identification of life-changing diagnoses in potentially healthy donor candidates

BACKGROUND

In order to ensure eligibility for living kidney donation, donor candidates undergo a thorough medical evaluation. This process might reveal hitherto undetected medical conditions, leading to refusal of the kidney donor candidate. Detection of such conditions may, however, also have a lifesaving effect. We report on 13 years of data from our living donor transplantation program on kidney donor candidates who were diagnosed with major medical conditions during evaluation.

MATERIALS AND METHODS

We performed a retrospective analysis of living kidney donor candidates who attended our transplant center between January, 2007 and December, 2019. The main focus was on newly diagnosed medical conditions that required immediate medical attention and their prognostic significance.

RESULTS

Of the 436 donor candidates who were evaluated for living kidney donation at our transplant center, 192 (44%) were accepted, while 244 (56%) were excluded from donation. Interestingly, 81 (33.1%) of the ineligible donor candidates were newly diagnosed as having a medical condition that required immediate attention. While 45 (18.5%) candidates were newly diagnosed with diabetes or prediabetes, 12 (4.9%) candidates had hitherto undetected malignancies, 10 candidates (4.1%) cardiac disease, five (2.0%) hypertension with end-organ damage, and four (1.6%) suffered from kidney disease. The remaining four candidates (1.6%) were diagnosed with gastrointestinal diseases, and one candidate (.4%) had an endocrine disorder.

CONCLUSION

A comprehensive evaluation process for living kidney donation facilitates the identification of life-changing diagnoses in a significant proportion of candidates and secures immediate medical attention.

Changing landscape of living kidney donation and the role of telemedicine

PURPOSE OF REVIEW

There has been a decline in living kidney donation over the last two decades. Donors from low-income families or racial/ethnic minorities face greater disproportionate geographic, financial, and logistical barriers to completing lengthy and complex evaluations. This has contributed to the decreased proportion of these subgroups. The authors view telemedicine as a potential solution to this problem.

RECENT FINDINGS

Since the initial decline of donors in 2005, biologically related donors have experienced a lack of growth across race/ethnicity. Conversely, unrelated donors have emerged as the majority of donors in recent years across race/ethnicity, except for unrelated black donors. Disparities in access to living kidney donation persist. Telemedicine using live-video visits can overcome barriers to access transplant centers and facilitate care coordination. In a U.S. survey, nephrologists, surgeons, coordinators, social workers, and psychologists/psychologists across transplant centers are favorably disposed to use telemedicine for donor evaluation/follow-up beyond the coronavirus disease 2019 pandemic. However, with the waning of relaxed telemedicine regulations under the Public Health Emergency, providers perceive payor policy and out-of-state licensing as major factors hindering telemedicine growth prospects.

SUMMARY

Permanent federal and state policies that support telemedicine services for living kidney donation can enhance access to transplant centers and help overcome barriers to donor evaluation.

Recommendations for living donor kidney transplantation

This Guide for Living Donor Kidney Transplantation (LDKT) has been prepared with the sponsorship of the Spanish Society of Nephrology (SEN), the Spanish Transplant Society (SET), and the Spanish National Transplant Organization (ONT). It updates evidence to offer the best chronic renal failure treatment when a potential living donor is available. The core aim of this Guide is to supply clinicians who evaluate living donors and transplant recipients with the best decision-making tools, to optimise their outcomes. Moreover, the role of living donors in the current KT context should recover the level of importance it had until recently. To this end the new forms of incompatible HLA and/or ABO donation, as well as the paired donation which is possible in several hospitals with experience in LDKT, offer additional ways to treat renal patients with an incompatible donor. Good results in terms of patient and graft survival have expanded the range of circumstances under which living renal donors are accepted. Older donors are now accepted, as are others with factors that affect the decision, such as a borderline clinical history or alterations, which when evaluated may lead to an additional number of transplantations. This Guide does not forget that LDKT may lead to risk for the donor. Pre-donation evaluation has to centre on the problems which may arise over the short or long-term, and these have to be described to the potential donor so that they are able take them into account. Experience over recent years has led to progress in risk analysis, to protect donors' health. This aspect always has to be taken into account by LDKT programmes when evaluating potential donors. Finally, this Guide has been designed to aid decision-making, with recommendations and suggestions when uncertainties arise in pre-donation studies. Its overarching aim is to ensure that informed consent is based on high quality studies and information supplied to donors and recipients, offering the strongest possible guarantees.

Long-term Medical Outcomes of Living Kidney Donors

Historically, to minimize risks, living kidney donors have been highly selected and healthy. Operative risks are well-defined, yet concern remains about long-term risks. In the general population, even a mild reduction in glomerular filtration rate (GFR) is associated with cardiovascular disease, chronic kidney disease, and end-stage kidney disease (ESKD). However, reduction in GFR in the general population is due to kidney or systemic disease. Retrospective studies comparing donors with matched general population controls have found no increased donor risk. Prospective studies comparing donors with controls (maximum follow-up, 9 years) have reported that donor GFR is stable or increases slightly, whereas GFR decreases in controls. However, these same studies identified metabolic and vascular donor abnormalities. There are a few retrospective studies comparing donors with controls. Each has limitations in selection of the control group, statistical analyses, and/or length of follow-up. One such study reported increased donor mortality; 2 reported a small increase in absolute risk of ESKD. Risk factors for donor ESKD are similar to those in the general population. Postdonation pregnancies are also associated with increased risk of hypertension and preeclampsia. There is a critical need for long-term follow-up studies comparing donors with controls from the same era, geographic area, and socioeconomic status who are healthy, with normal renal function on the date matching the date of donation, and are matched on demographic characteristics with the donors. These data are needed to optimize donor candidate counseling and informed consent.

The altruistic elderly, a valuable but unrecognised kidney donor group. A case report of an 85-year-old unspecified kidney donor

Background

Kidney transplantation is the definitive treatment for end stage renal disease (ESRD), offering improved quality of life and survival benefit over remaining on dialysis. There is, however, a prevailing significant mismatch between patients awaiting transplantation and available donor kidneys. Over time, initial stringent donor criteria have broadened and organs from extended criteria donors (ECDs) and older donors are now being accepted for transplantation. The spectrum of living donors has also undergone a change from close family members to an increasingly non-related, non-directed altruistic donors, newly classified as ‘unspecified’ donors. Unspecified elderly donors could be a potential untapped resource to expanding the kidney donor pool globally.

Case Presentation

We present a case of an 85 year and 8 months old individual, who donated to an unrelated non-directed matched recipient in the national deceased donor transplant waiting list with excellent donor and recipient outcomes at 7 years.

Conclusion

To our knowledge she is one of the oldest reported unspecified living kidney donors in the world to date. This case illustrates that elderly donors in good health can come forward to donate, knowing that it is safe and valuable. Once the immediate perioperative challenges after kidney donation are managed, elderly donors rarely encounter long term sequelae. We therefore report this case to increase awareness and refocus attention of transplant teams on elderly donors as a potential untapped group to help address the organ shortage problem in renal transplantation.

Prostanoid receptors in hyperfiltration-mediated glomerular injury: Novel agonists and antagonists reveal opposing roles for EP2 and EP4 receptors

Increased fluid-flow shear stress (FFSS) contributes to hyperfiltration-induced podocyte and glomerular injury resulting in progression of chronic kidney disease (CKD). We reported that increased FFSS in vitro and in vivo upregulates PGE2 receptor EP2 (but not EP4 expression), COX2-PGE₂ -EP2 axis, and EP2-linked Akt-GSK3β-β-catenin signaling pathway in podocytes. To understand and use the disparities between PGE2 receptors, specific agonists, and antagonists of EP2 and EP4 were used to assess phosphorylation of Akt, GSK3β and β-catenin in podocytes using Western blotting, glomerular filtration barrier function using in vitro albumin permeability (P_alb ) assay, and mitigation of hyperfiltration-induced injury in unilaterally nephrectomized (UNX) mice at 1 and 6 months. Results show an increase in P_alb by PGE₂ , EP2 agonist (EP2^AGO ) and EP4 antagonist (EP4^ANT ), but not by EP2 antagonist (EP2^ANT ) or EP4 agonist (EP4^AGO ). Pretreatment with EP2^ANT blocked the effect of PGE₂ or EP2^AGO on P_alb . Modulation of EP2 and EP4 also induced opposite effects on phosphorylation of Akt and β-Catenin. Individual agonists or antagonists of EP2 or EP4 did not induce significant improvement in albuminuria in UNX mice. However, treatment with a combination EP2^ANT  + EP4^AGO for 1 or 6 months caused a robust decrease in albuminuria. EP2^ANT  + EP4^AGO combination did not impact adaptive hypertrophy or increased serum creatinine. Observed differences between expression of EP2 and EP4 on the glomerular barrier highlight these receptors as potential targets for intervention. Safe and effective mitigating effect of EP2^ANT  + EP4^AGO presents a novel opportunity to delay the progression of hyperfiltration-associated CKD as seen in transplant donors.

A prediction model with lifestyle factors improves the predictive ability for renal replacement therapy: a cohort of 442 714 Asian adults

Background

There are limited renal replacement therapy (RRT) prediction models with good performance in the general population. We developed a model that includes lifestyle factors to improve predictive ability for RRT in the population at large.

Methods

We used data collected between 1996 and 2017 from a medical screening in a cohort comprising 442 714 participants aged 20 years or over. After a median follow-up of 13 years, we identified 2212 individuals with end-stage renal disease (RRT, n: 2091; kidney transplantation, n: 121). We built three models for comparison: model 1: basic model, Kidney Failure Risk Equation with four variables (age, sex, estimated glomerular filtration rate and proteinuria); model 2: basic model + medical history + lifestyle risk factors; and model 3: model 2 + all significant clinical variables. We used the Cox proportional hazards model to construct a points-based model and applied the C statistic.

Results

Adding lifestyle factors to the basic model, the C statistic improved in model 2 from 0.91 to 0.94 (95% confidence interval: 0.94, 0.95). Model 3 showed even better C statistic value i.e., 0.95 (0.95, 0.96). With a cut-off score of 33, model 3 identified 3% of individuals with RRT risk in 10 years. This model detected over half of individuals progressing to RRT, which was higher than the sensitivity of cohort participants with stage 3 or higher chronic kidney disease (0.53 versus 0.48).

Conclusions

Our prediction model including medical history and lifestyle factors improved the predictive ability for end-stage renal disease in the general population in addition to chronic kidney disease population.

Clinical Trial Considerations in Developing Treatments for Early Stages of Common, Chronic Kidney Diseases: A Scientific Workshop Cosponsored by the National Kidney Foundation and the US Food and Drug Administration

In the past decade, advances in the validation of surrogate end points for chronic kidney disease (CKD) progression have heightened interest in evaluating therapies in early CKD. In December 2020, the National Kidney Foundation sponsored a scientific workshop in collaboration with the US Food and Drug Administration (FDA) to explore patient, provider, and payor perceptions of the value of treating early CKD. The workshop reviewed challenges for trials in early CKD, including trial designs, identification of high-risk populations, and cost-benefit and safety considerations. Over 90 people representing a range of stakeholders including experts in clinical trials, nephrology, cardiology and endocrinology, patient advocacy organizations, patients, payors, health economists, regulators and policy makers attended a virtual meeting. There was consensus among the attendees that there is value to preventing the development and treating the progression of early CKD in people who are at high risk for progression, and that surrogate end points should be used to establish efficacy. Attendees also concluded that cost analyses should be holistic and include aspects beyond direct savings for treatment of kidney failure; and that safety data should be collected outside/beyond the duration of a clinical trial. Successful drug development and implementation of effective therapies will require collaboration across sponsors, patients, patient advocacy organizations, medical community, regulators, and payors.

Approach to genetic testing to optimize the safety of living donor transplantation in Alport syndrome spectrum

Alport syndrome spectrum can be considered as a group of genetic diseases affecting the major basement membrane collagen type IV network in various organs including the ear, eye, and kidney. The living donor candidate evaluation is an ever-changing landscape. Recently, next-generation sequence (NGS) panels have become readily available and provide opportunities to genetically screen recipient and donor candidates for collagen network gene variants. In this review, our aim is to provide a comprehensive update on the role of genetic testing for the evaluation of potential living kidney donors to kidney candidates with Alport syndrome spectrum. We examine the utility of genetic testing in the evaluation of potential donors for recipients with Alport syndrome spectrum, and discuss risks and unresolved challenges. Suggested algorithms in the context of related and unrelated donation are offered. In contemporary practice, an approach to the evaluation of living donor candidates for transplant candidates with Alport syndrome spectrum can incorporate genetic testing in algorithms tailored for donor-recipient relationship status. Ongoing research is needed to inform optimal practice.

Short-term Outcome of Danish Kidney Donors: Postoperative Complications and Labor Affiliation

BACKGROUND

Living kidney donation is safe and effective, but disincentives to donation include risk of short- and long-term complications, which need to be addressed in order to ensure care of live kidney donors.

METHODS

From January 1, 2016 to December 31, 2019, 123 living kidney donors (LKDs) underwent LKD nephrectomy at Aarhus University Hospital, Aarhus, Denmark. Data from The Scandiatransplant registry and patient records were reviewed in order to identify short-term postoperative complications within 90 days after donation, as well as affiliation to the labor market and health data at follow-up. The Clavien-Dindo classification of surgical complications with modifications by Kocak et al was used to categorize minor and major complications.

RESULTS

There were available data for 119 of 123 LKDs. Of these, 25 (21%) developed minor complications and 4 (3%) developed major complications. Ninety LKDs (76%) had an uneventful course without any complications. The most common complications were pain and nausea that required additional medical treatment. Seventy-two of the 82 LKDs working before donation had returned to work within 3 months after donor nephrectomy. No one retired or became disabled as a result of being a live kidney donor.

CONCLUSIONS

Short-term follow up of the LKDs showed that most donors experienced an uneventful course and that the frequency of major complications was low. Donation did not seem to impact the ability to resume work. At the 90-day follow-up the majority of donors with both minor and major complications resumed work and reported full convalescence at the same level as donors without any complications. Nine of the LKDs (8%), all women, were out of work for >3 months with the main reason being fatigue.

Understanding Structural Racism as a Barrier to Living Donor Kidney Transplantation and Transplant Care

Recent Findings

Black and Hispanic patients carry higher burden of kidney disease, yet have lower access to LDKT. Until recently, these differences were thought to be due to medical co-morbidities and variation in transplant center practices. However, recent studies have shown that systemic and structural inequities related to race may be one of the major drivers.

Purpose of Review

In this paper, we examine the definition of race and systemic racism, then describe patient-, transplant center–, and society-level barriers to LDKT. We identify how social determinants, cultural biases and mistrust in medical system, influence behaviors, and provider racial profiling affects all phases of transplant evaluation. Finally, we discuss initiatives to overcome some of these barriers, starting from federal government, national organizations, transplant centers, and community partners.

Summary

Examining structural biases in transplant practices is an important step to developing solutions to address disparities in health care access and outcomes for patients who need and receive transplants.

Long-Term Follow-up of Over 600 Living Related Kidney Donors: Single-Center Experience

OBJECTIVES

Kidney transplant is the treatment of choice in patients with end-stage renal disease because it offers improved survival and better quality of life. Although most epidemiologic studies have suggested that living kidney donors have a minimal lifetime risk of developing end-stage renal disease, long-term complications and physiologic and psychologic sequelae resulting from donation remain unclear. Here, we examined the long-term results of living-related kidney donors who donated kidneys at the Başkent University Ankara Hospital over the past 25 years.

MATERIALS AND METHODS

We were able to examine 607 kidney transplant donors (mean age of 52.03 ± 11.54 years) who were seen at our center from 1986 to 2021 and who agreed to a general health evaluation. Collected data included donor age, sex, blood type, body mass index, duration after donation, blood pressure measurements, biochemical parameters, abdominal ultrasonograph for size, structure, and renal blood flow of the solitary kidney, comorbid conditions, chronic drug use, and surgical procedures after donation.

RESULTS

Mean time after donation was 10.4 ± 3.2 years. Twenty-four donors (3.9%) were diagnosed with diabetes and 21 (3.4%) with thyroid disease, 64 (10.5%) developed hypertension, and 48 (8.8%) developed atherosclerotic cardiovascular disease. Obesity was found to be an increasing problem in our donor population, with 174 (28.6%) developing mild to moderate obesity (body mass index >25 kg/m2). Older age, obesity, smoking, and hyperlipidemia were found to be the major and independent risk factors of both hypertension and atherosclerotic cardiovascular disease in donors. None of our donors developed endstage renal disease.

CONCLUSIONS

Obesity and hypertension were the most common comorbidities that developed in our kidney donor population. Our principle is to avoid unrelated and nondirected donors because of the possible long-term complications. Unrelated donors may be desperate if a family member needs donation in the future.