Proteinuria and reduced kidney function in living kidney donors: A systematic review, meta-analysis, and meta-regression

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.

Analysis of sexual dysfunction development among male and female living kidney donors

INTRODUCTION

Living kidney donations (LKDs) face a persistent demand for patients with end-stage renal disease, emphasizing the importance of LKDs' growth and success. Although living kidney donors generally exhibit excellent survival rates, little research has explored the development of long-term sexual dysfunction following LKD.

OBJECTIVES

This study aimed to analyze differences in 5-year sexual dysfunction outcomes between male and female living kidney donors, utilizing the TriNetX database, a federated network of electronic medical records from multiple U.S. healthcare organizations.

METHODS

A propensity score-matched cohort study compared 45-year sexual dysfunction outcomes in adult male and female living kidney donors from December 2013 to December 2022. Cohorts were matched on age; sex; race and ethnicity; diabetes, cardiovascular, genitourinary, and psychiatric comorbidities; lifestyle-related factors; and medications that may impact normal sexual functioning. Primary outcomes included hazard ratio (HR) for decreased libido, sexual dysfunction (composite of male erectile dysfunction, ejaculatory disorders, vaginismus/dyspareunia, infertility, orgasmic disorders, arousal/desire disorders), and sexually transmitted diseases. Secondary outcomes assessed sex counseling and interpersonal relationship issues with spouses or partners.

RESULTS

The matched cohorts included 2315 patients each (male, female), and the mean age was 42.3 ± 12.5 years. At 5 years, male donors had a significantly higher HR for sexual dysfunction (HR, 3.768; 95% confidence interval, 1.929-7.358). Erectile dysfunction occurred in 1% of male patients, while vaginismus/dyspareunia affected <1% of female patients. Other sexual disorders, decreased libido, sexually transmitted diseases, and incidences of sexual and interspousal counseling were not significantly different.

CONCLUSION

Male living kidney donors faced a higher risk of developing sexual dysfunction 5 years after donation. While LKD remains a safe and viable alternative, clinicians and donors should be mindful of the potential association with sexual dysfunction postdonation. Further research may enhance support for the well-being of living kidney donors.

Pros and cons of live kidney donation in prediabetics: A critical review and way forward

There is shortage of organs, including kidneys, worldwide. Along with deceased kidney transplantation, there is a significant rise in live kidney donation. The prevalence of prediabetes (PD), including impaired fasting glucose and impaired glucose tolerance, is on the rise across the globe. Transplant teams frequently come across prediabetic kidney donors for evaluation. Prediabetics are at risk of diabetes, chronic kidney disease, cardiovascular events, stroke, neuropathy, retinopathy, dementia, depression and nonalcoholic liver disease along with increased risk of all-cause mortality. Unfortunately, most of the studies done in prediabetic kidney donors are retrospective in nature and have a short follow up period. There is lack of prospective long-term studies to know about the real risk of complications after donation. Furthermore, there are variations in recommendations from various guidelines across the globe for donations in prediabetics, leading to more confusion among clinicians. This increases the responsibility of transplant teams to take appropriate decisions in the best interest of both donors and recipients. This review focuses on pathophysiological changes of PD in kidneys, potential complications of PD, other risk factors for development of type 2 diabetes, a review of guidelines for kidney donation, the potential role of diabetes risk score and calculator in kidney donors and the way forward for the evaluation and selection of prediabetic kidney donors.

Consequences of kidney donation by age in Japanese living kidney donors: a single-center study

BACKGROUND

Elderly living kidney donors (LKDs) are becoming increasingly important in countries with a high prevalence of living-donor kidney transplants and an aging society. This study explored the features of elderly LKDs, focusing on their subsequent outcomes.

METHODS

This single-center, retrospective, observational study included eligible LKDs who donated their kidneys between April 2008 and July 2022. LKDs were categorized into an elderly (≥70 years at donation) or a non-elderly group (<70 years). We examined pre-operative characteristics and post-operative outcomes, such as kidney function, complications, development of end-stage kidney disease (ESKD), and mortality.

RESULTS

Of the 188 LKDs observed for a median of 5.7 years, 31 were in the elderly group (16.5%) and 157 (83.5%) were in the non-elderly group (mean age 72.5 ± 2.7 and 58.2 ± 7.3 years, respectively). No significant differences were observed in hospital stay length or peri-operative complications between groups. Both groups experienced a similar decline in post-donation estimated glomerular filtration rate (eGFR)-approximately 37%. In the elderly group, four LKDs died, and one progressed to ESKD. In the non-elderly group, two LKDs died, and none progressed to ESKD. The cause of death was not strongly suspected to be associated with the donation.

CONCLUSIONS

eGFR was maintained even in elderly LKDs post-donation. Prioritizing LKDs' safety is paramount; however, donations from elderly people would be acceptable, considering their life expectancy. This can expand the pool of living kidney donors and address the growing demand for kidney transplants.

Risk Factors for Developing Low Estimated Glomerular Filtration Rate and Albuminuria in Living Kidney Donors

Rationale & Objective

Chronic kidney disease is associated with significant morbidity and mortality in the general population, but little is known about the incidence and risk factors associated with developing low estimated glomerular filtration rate (eGFR) and moderate-severe albuminuria in living kidney donors following nephrectomy.

Study Design

Retrospective, population-based cohort study.

Setting & Participants

Kidney donors in Alberta, Canada.

Exposure

Donor nephrectomy between May 2001 and December 2017.

Outcome

Two eGFR measurements <45 mL/min/1.73 m2 or 2 measurements of moderate or severe albuminuria from 1-year postdonation onwards that were at least 90 days apart.

Analytical Approach

Associations between potential risk factors and the primary outcome were assessed using Cox proportional hazard regression analyses.

Results

Over a median follow-up period of 8.6 years (IQR, 4.7-12.6 years), 47 of 590 donors (8.0%) developed sustained low eGFR or moderate-severe albuminuria with an incidence rate of 9.2 per 1,000 person-years (95% confidence interval, 6.6-11.8). The median time for development of this outcome beyond the first year after nephrectomy was 2.9 years (IQR, 1.4-8.0 years). Within the first 4 years of follow-up, a 5 mL/min/1.73 m2 lower predonation eGFR increased the hazard of developing postdonation low eGFR or moderate-severe albuminuria by 26% (adjusted HR, 1.26; 95% CI, 1.10-1.44). Furthermore, donors were at higher risk of developing low eGFR or albuminuria if they had evidence of predonation hypertension (adjusted HR, 2.52; 95% CI, 1.28-4.96) or postdonation diabetes (adjusted HR, 4.72; 95% CI, 1.54-14.50).

Limitations

We lacked data on certain donor characteristics that may affect long-term kidney function, such as race, smoking history, and transplant-related characteristics.

Conclusions

A proportion of kidney donors at an incidence rate of 9.2 per 1,000 person-years will develop low eGFR or albuminuria after donation. Donors with lower predonation eGFR, predonation hypertension, and postdonation diabetes are at increased risk of developing this outcome.

Pregnancy in Living Kidney Donors: An Evidence-Based Review

Purpose of review

To review the current studies and guidelines on the risk of adverse pregnancy outcomes in female kidney donors.

Recent findings

Living kidney donors include a significant amount of young women of child-bearing age. Safety and possible risks of pregnancy after donation are a concern for female kidney donor candidates. Many current studies indicate a higher risk of preeclampsia in women after kidney donation. Considering the increasing number of living kidney donors, the maternal outcomes of living kidney donation is an active area of research.

Summary

Guidelines and consensus statements on the risk of pregnancy in living kidney donors recommend close monitoring of blood pressure, weight gain, and proteinuria during pregnancy. Current studies indicate an increased risk of hypertensive disorders of pregnancy in living kidney donors. Counseling and informing donor candidates about the possible risks is important.

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.

Long-term end-stage renal disease risks after living kidney donation: a systematic review and meta-analysis

BACKGROUND

Recent studies have shown that donor nephrectomy can induce renal function impairment. However, few meta-analysis studies about this have proceeded. Therefore, the objective of this systematic review and meta-analysis including all data of recent research studies was to determine whether living donor nephrectomy (LDN) could induce renal function impairment.

METHODS

By November 2020, comprehensive literature searches were performed on PubMed, Embase, and Cochrane databases. Inclusion criteria were: (1) observational studies with data about overall end-stage renal disease (ESRD) or chronic kidney disease (CKD) of living kidney donors, (2) control group consisted of people without donor nephrectomy, and (3) outcomes of studies included long-term end-stage renal disease risks after living kidney donation. Risk of Bias in Non-randomized Studies of interventions (ROBINS-I) assessment tool was used to evaluate our methodological quality.

RESULTS

The qualitative review included 11 studies and the meta-analysis included 5 studies. In the meta-analysis, the integrated overall ESRD risk was 5.57 (95% CI: 2.03-15.30). Regarding the overall risk of bias using ROBINS-I assessment tool, 0 studies was rated as "Low", 7 studies were rated as "moderate", 2 studies were rated as "Serious", and two studies were rated as "Critical".

CONCLUSIONS

Our study showed that LDN increased ESRD risk in LDN patients. However, in our meta-analysis, variables in included studies were not uniform and the number of included studies was small. To have a definite conclusion, meta-analyses of well-planned and detailed studies need to be conducted in the future.

Whole and cortical kidney volume predict 5-year post-nephrectomy eGFR in Indian living kidney donors

AIM

To study the additional utility of pre-nephrectomy whole and cortical kidney volumes (WKV, CKV) in predicting long-term post-nephrectomy kidney function in Indian living kidney donors (LKDs).

METHODS

This retrospective cohort study included all LKDs who underwent nephrectomy between 1 January 2006 and 31 December 2015 at our centre, had pre-nephrectomy height, weight and computed tomography (CT) angiography with arterial and nephrographic phase documented, and 5-year post-nephrectomy creatinine values measured. Correlation between body surface area (BSA) adjusted pre-nephrectomy total CKV, WKV and pre-nephrectomy CKD EPI eGFR; BSA-adjusted remnant pre-nephrectomy CKV (rCKV), WKV (rWKV) and 5-year post-nephrectomy CKD EPI creatinine eGFR (5yeGFRCr ); predictors of 5yeGFRCr  < 70% of pre-nephrectomy CKD EPI creatinine eGFR (pre-eGFRCr ), and an equation to predict 5yeGFRCr from pre-nephrectomy variables were calculated.

RESULTS

A total of 196 LKDs (74% female, mean age 41.7 ± 11.0 years) were included in the study. Total WKV showed higher correlation with pre-nephrectomy eGFR than CKV, the highest with CKD EPI cystatin eGFR. Remnant WKV showed higher correlation than rCKV with post-nephrectomy eGFRCr and this increased over time. Older age, lower rWKV or rCKV, higher BSA, and higher pre-eGFRCr identified LKDs with 5yeGFRCr  < 70% of pre-eGFRCr , with rCKV identifying a higher proportion (4.5%) of such LKDs. A model including rWKV or rCKV predicted 5yeGFRCr better than one including age, gender, BSA and pre-eGFRCr alone.

CONCLUSION

Inclusion of pre-nephrectomy remnant CKV and WKV into models for 5yeGFRCr and sub-optimal post-nephrectomy adaptation in Indian LKDs improves their accuracy. CKD EPI cystatin eGFR correlates better with functional renal mass.

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.

Clinical indicators of slow graft function and outcome after pediatric kidney transplantation

BACKGROUND

Lesser degrees of perioperative ischemia-reperfusion injury that does not require dialysis may nonetheless influence allograft outcomes, necessitating evaluation of suitable surrogate indicators of perioperative allograft injury.

METHODS

This retrospective analysis of pediatric kidney transplants evaluated two indicators representing pace and completeness of recovery, for association with 12-month estimated glomerular filtration rate (eGFR) and first-year rate of eGFR decline: time to creatinine nadir (TTN) and ratio of recipient/donor unadjusted GFR (uGFR_R/D ) at 1-month post-transplant. Donor, recipient, and perioperative risk factors were tested further for association with these 2 indicators.

RESULTS

179 patients (190 transplants) aged 13 (IQR 7-17) years and 56% male were included. Twelve-month eGFR was strongly associated with unadjusted GFR at 1 month (uGFR_1M , p < .001) and uGFR_R/D (p = .003), but not with TTN. None of the indicators was associated with the rate of subsequent eGFR decline after 1-month post-transplant. As a potential surrogate indicator, uGFR_1M is effectively modeled by TTN and uGFR_R/D (adjusted R²  = 0.57) and is associated with 12-month eGFR (β = 0.81 ± 0.08; p < .001). Clinical factors associated with uGFR_R/D included donor uGFR (p < .001), BSA (p = .026), age (p = .074), and recipient BSA (p < .001). Factors associated with pace of recovery (TTN) included donor uGFR (p = .018), type (p = .019), and recipient BSA (p = .022).

CONCLUSIONS

The uGFR_R/D ratio, but not TTN, is a useful indicator of perioperative allograft damage that is associated with one-year functional outcome; and uGFR_1M is a potential early surrogate outcome. Donor, recipient, and perioperative factors that are associated with slow allograft function are identified.

The Living Kidney Donor Safety Study: Protocol of a Prospective Cohort Study

Background

Living kidney donation is considered generally safe in healthy individuals; however, there is a need to better understand the long-term effects of donation on blood pressure and kidney function.

Objectives

To determine the risk of hypertension in healthy, normotensive adults who donate a kidney compared with healthy, normotensive non-donors with similar indicators of baseline health. We will also compare the 2 groups on the rate of decline in kidney function, the risk of albuminuria, and changes in health-related quality of life.

Design Participants and Setting

Prospective cohort study of 1042 living kidney donors recruited before surgery from 17 transplant centers (12 in Canada and 5 in Australia) between 2004 and 2014. Non-donor participants (n = 396) included relatives or friends of the donor, or donor candidates who were ineligible to donate due to blood group or cross-match incompatibility. Follow-up will continue until 2021, and the main analysis will be performed in 2022. The anticipated median (25th, 75th percentile, maximum) follow-up time after donation is 7 years (6, 8, 15).

Measurements

Donors and non-donors completed the same schedule of measurements at baseline and follow-up (non-donors were assigned a simulated nephrectomy date). Annual measurements were obtained for blood pressure, estimated glomerular filtration rate (eGFR), albuminuria, patient-reported health-related quality of life, and general health.

Outcomes

Incident hypertension (a systolic/diastolic blood pressure ≥ 140/90 mm Hg or receipt of anti-hypertensive medication) will be adjudicated by a physician blinded to the participant's donation status. We will assess the rate of change in eGFR starting from 12 months after the nephrectomy date and the proportion who develop an albumin-to-creatinine ratio ≥3 mg/mmol (≥30 mg/g) in follow-up. Health-related quality of life will be assessed using the 36-item RAND health survey and the Beck Anxiety and Depression inventories.

Limitations

Donation-attributable hypertension may not manifest until decades after donation.

Conclusion

This prospective cohort study will estimate the attributable risk of hypertension and other health outcomes after living kidney donation.

Pregnancy after living kidney donation, a systematic review of the available evidence, and a review of the current guidance

Understanding and communicating the risk of pregnancy complications post-living kidney donation is imperative as the majority of living kidney donors (LKD) are women of childbearing age. We aimed to identify all original research articles examining complications in post-donation pregnancies and compared the quality and consistency of related guidelines. We searched Embase, MEDLINE, PubMed, society webpages, and guideline registries for English-language publications published up until December 18, 2020. Ninety-three articles were screened from which 16 studies were identified, with a total of 1399 post-donation pregnancies. The outcome of interest, post-donation pregnancy complications, was not calculable, and only a narrative synthesis of the evidence was possible. The absolute risk of pre-eclampsia increased from ~1%-3% pre-donation (lower than the general population) to ~4%-10% post-donation (comparable to the general population). The risks of adverse fetal and neonatal outcomes were no different between post-donation and pre-donation pregnancies. Guidelines and consensus statements were consistent in stating the need to inform LKDs of their post-donation pregnancy risk, however, the depth and scope of this guidance were variable. While the absolute risk of pregnancy complications remains low post-donation, a concerted effort is required to better identify and individualize risk in these women, such that consent to donation is truly informed.

Long-term renal and cardiovascular outcome of living kidney donors: A single-center retrospective observation study

Background

The nephrectomy for donation reduces the renal parenchyma and glomerular filtration rate (GFR). It is important to understand the clinical consequences of kidney donation by a living donor.

Methods

In this single-center, observational, retrospective study, we defined the renal and cardiovascular outcomes of living kidney donors. We analyzed data of 124 donors who donated at the Kidney Transplant Center (TC) of Bari between February 2002 and December 2018. Biometric data collected at visit 0, that is, at the time of the study of the donor candidate, and at visit 1, or rather at the last nephrological checkup (October-2018/August-2019) were compared.

Results

An overall drop in GFR of 29 mL/min was observed over the analyzed period of 81+/-59 months. At visit 1, two donors developed chronic renal failure, including one in ESKD who underwent a kidney transplant. No relationship between age at donation and GFR drop was found. A trend toward an increase in obese people was reported; 28% of patients had compensated dyslipidemia and 35% were treated for hypertension. During the follow-up time, 3% had major cardiovascular events and 24% were lost to follow-up. One patient died.

Conclusion

The age of the donor does not represent a basic element for reducing GFR or for the occurrence of major cardiovascular events. Furthermore, older donor candidates, in optimal health, should not be excluded from the donation. It is important to promote careful and timely follow-up of the donor, preventing the most common clinical consequences of nephrectomy, in consideration of the poor compliance of a large part of donors over the long-term post-donation period.

Robotic-assisted laparoscopy living donor nephrectomy: Technique and results of a monocentric retrospective series

INTRODUCTION

Robot-assisted nephrectomy for living kidney donation (LKD) has been described in the literature as a safe and reproducible technique in high volume centers with extensive robotic surgery experience. Any surgical procedure in a healthy individual ought to be safe in regards to complications. The objective of this study was to evaluate the Robotic-assisted Living Donor Nephrectomy (RLDN) experience in a robotic surgery expert center.

METHODS

This is a retrospective study from 11/2011 and 12/2019. In total, 118 consecutive Living Donor (LD) kidney transplants were performed at our institution. All the procedures were performed by robotic-assisted laparoscopic approach. Extraction was performed by iliac (IE), vaginal (VE) or umbilical extraction (UE). The left kidney was preferred even if the vascular anatomy was not modal.

RESULTS

For donors: the median operative time was 120min with 50mL of blood loss. The median warm ischemia time was 4min, with a non-significant shorter duration with the UE (4min) in comparison with IE or VE (5min). Nine patients had postoperative complications including 1 grade II (blood transfusion) and 1 grade IIIb (vaginal bleeding after VE). None of our procedures were converted to open surgeries and no deaths were reported. For the recipients: 1.7% presented delayed graft function; their median GFR at 1 year was 61mL/min/1.73m².

CONCLUSION

RLDN in an expert center appears to be a safe technique. The advantages of the robot device in terms of ergonomy don't hamper the surgical outcomes. Donor, recipient and graft survivals seem comparable to the reported laparoscopic outcomes in the literature.

LEVEL OF EVIDENCE: 4

Predictive factors of glomerular filtration rate loss associated with living kidney donation: a single-center retrospective study

PURPOSE

Living kidney donors (LKD) partially compensate the initial loss of glomerular filtration rate (GFR), a phenomenon known as renal functional reserve (RFR). RFR is reduced in the elderly, a population with increased prevalence of chronic kidney disease. We hypothesized that the selected, healthy population of LKD, would specifically inform about the physiological determinants of the RFR and studied it using measured GFR (mGFR).

METHODS

We retrospectively analyzed pre-donation and post-donation mGFR in 76 LKD from Tenon Hospital (Paris, France) between 2002 and 2018. In addition to GFR measurements, we collected pre-donation morphologic parameters, demographic data, and kidney volumes.

RESULTS

Mean pre-donation mGFR was 90.11 ± 12.64 mL/min/1.73 m² and decreased to 61.26 ± 9.57 mL/min/1.73 m² 1 year after donation. Pre-donation mGFR correlated with age (p = 0.0003), total kidney volume (p = 0.0004) and pre-donation serum creatinine (p = 0.0453). Pre-donation mGFR strongly predicted 1-year post-donation mGFR. Mean RFR (increase in GFR of the remnant kidney between pre-donation and post-donation) was 36.67 ± 16.67% 1 year after donation. In the multivariate linear model, RFR was negatively correlated to total kidney volume (p = 0.02) but not with age or pre-donation serum creatinine.

CONCLUSIONS

We found that pre-donation mGFR decreases with age and identified low total kidney volume as a predictor of RFR in healthy individuals. This suggests an adaptative and reversible decrease in kidney function rather than age-related damage. Older subjects may have reduced metabolic requirements with subsequent reduction in glomerular filtration and kidney volume and preserved RFR. Therefore, low GFR in older subjects should not preclude kidney donation.

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.

Is a Patient with Paget's Disease of Bone Suitable for Living Kidney Donation?-Decision-Making in Lack of Clinical Evidence

Living donor kidney transplantation is a widely performed medical procedure. Living kidney donation requires an in-depth health assessment of candidates. The potential living kidney donor must remain healthy after kidney removal. A consequence of donation can be a decrease in glomerular filtration rate (GFR), and donors can become at risk of developing chronic kidney disease (CKD). We present a rationale for potential living kidney donor withdrawal due to Paget's disease of bone (PDB) based on a literature review. The treatment for PDB includes the use of, for example, non-steroidal anti-inflammatory drugs (NSAIDs), which can lead to acute kidney injury (AKI) as well as CKD, or bisphosphonates, which are not recommended for patients with decreased GFR.

Assessment of cognitive functioning after living kidney donation: A cross-sectional pilot study

Background

Chronic kidney disease (CKD) has emerged as a risk factor for cognitive impairment. Living kidney donation results in reduction of the donors’ renal function. This is considered acceptable in general but possible associations with cognitive function have not yet been studied.

Methods

Sixty living kidney donors (LKD), who had donated between 2003 and 2012 at Hannover Medical School, underwent neurocognitive testing including attentional and memory testing. In a cross-sectional design results were compared with data of healthy controls (n = 40) and with norm data given in the respective test manuals adjusted for age, sex, and education.

Results

The median age of the LKD was 58 (range 39–70) years and the median time since donation was 7 (range 4–14) years. The LKD did not differ from controls in most of the cognitive test results and a composite attention test sum score. However, LKD did worse than controls in tests of working memory, parallel processing of stimuli, and sustained attention. No differences were found regarding quality of life. In LKD cognitive test results correlated significantly only with educational level but not with time since transplantation, eGFR, somatic comorbidity, quality of life and levels of fatigue, distress, depression, and anxiety.

Conclusions

Our data show a fairly normal performance of LKD in most attentional and memory tests. However, our pilot study also suggests some cognitive impairment in attention tests in LKD which would need to be confirmed in longitudinal prospective studies.

JCV viruria associates with suboptimal recovery of kidney function three years after living kidney donation

ABSTRACT Introduction: Few studies have investigated pre-donation factors that could affect renal recovery after living kidney donation (LKD). We retrospectively investigated the role of John Cunningham virus (JCV) infection and other pre-donation factors on the magnitude of kidney function decline after LKD. Methods: Urine JCV viral loads, glomerular filtration rate, and blood pressure were evaluated in 60 consecutive LK donors before donation. Suboptimal compensatory hypertrophy was defined as an eGFR <60% of the pre-donation eGFR. Results: LKD (40% JCV infected) were followed for 3.2±1.6 years. No association was found between age, gender, and baseline hypertension with 1st, 2nd, 3rd, and 4th years post-donation eGFR <60% of the pre-donation eGFR. Mean eGFR recovery at the 3rd year after donation was lower in JCV infected donors vs non-infected donors (61.8% vs 71.0%, p=0.006). Conclusion: We hypothesized that JCV could shift glomeruli into a hyperfiltration state before nephrectomy, modulating the magnitude of compensatory hypertrophy after donation. Conversely, JCV might curtail the ability of the remaining kidney to promote hyperfiltration. Longer follow up is needed to determine whether JCV viruria ultimately leads to lower eGFR over time or if it is a protective factor for the remaining kidney.

OUP accepted manuscript

Background

In living kidney transplantation there are two different individuals, a healthy donor and a renal transplant recipient. This is an excellent human model to study factors that influence kidney function in the context of reduced renal mass and the adaptation of two comparable kidneys to different metabolic demands.

Methods

We analyzed the changes in measured glomerular filtration rate (GFR, iohexol) from pretransplantation to 12 months after transplantation in 30 donor–recipient pairs. Each donor was compared with his/her recipient. We defined a priori three different groups based on GFR differences at 12 months: donor > recipient (Group A; 78 ± 8 versus 57 ± 8 mL/min), donor < recipient (Group B; 65 ± 11 versus 79 ± 11 mL/min) and donor ≈ recipient (Group C; 66 ± 7 versus 67 ± 7 mL/min). Other factors like donor/recipient mismatches in body mass index (BMI), surface area and gender were evaluated.

Results

In Group A donors were mostly male and recipients were female (75% each). Donors had a higher baseline weight than their recipients. During follow-up, weight remained stable in donors but increased 7% in recipients. In Group B donors were mostly female (60%) and recipients male. At baseline, donors had a lower weight than recipients. At 12 months, weight was stable in donors but increased in recipients. In Group C donors were mostly (75%) female and recipients male. At baseline, donors had a higher BMI than their recipients. At 12 months, BMI was stable in donors but increased 14% in recipients. In multivariable analysis, higher GFR at 12 months was associated with higher baseline weight and GFR in donors and with male gender and higher baseline weight in recipients.

Conclusions

Kidneys from living donors are more ‘plastic’ than originally thought and respond to metabolic demands and weight changes of their new host. These changes should be taken into account when assessing GFR outcomes in this population.

Is It Time to Utilize Genetic Testing for Living Kidney Donor Evaluation?

Living donor kidney transplantation is an effective strategy to mitigate the challenges of solid organ shortage. However, being a living kidney donor is not without risk, as donors may encounter short- and long-term complications including the risk of developing chronic kidney disease, end-stage kidney disease, hypertension, and possible pregnancy-related complications. Although the evaluation of potential living donors is a thorough and meticulous process with the intention of decreasing the chance of complications, particularly in donors who have lifetime risk projection, risk factors for kidney disease including genetic predispositions may be missed because they are not routinely investigated. This type of testing may not be offered to patients due to variability and decreased penetrance of symptoms and lack of availability of appropriate genetic testing and genetic specialists. We report a case of a middle-aged woman with a history of gestational diabetes and preeclampsia who underwent an uneventful living kidney donation. She developed postdonation nonnephrotic range proteinuria and microscopic hematuria. Given the risk of biopsy with a solitary kidney, genetic testing was performed and revealed autosomal dominant Alport syndrome. Our case underscores the utility of genetic testing. Hopefully, future research will examine the incorporation of predonation genetic testing into living kidney donor evaluation.

Safety, clinical and laboratory characteristics of donors with thalassemia minor in living donor kidney transplant: a case series

Background

Due to the increasing demand for kidney transplants, sometimes donors with underlying medical conditions can be considered for living kidney donor transplant. Thalassemia is amongst the most common inherited disorders of hemoglobin globally, which is not restricted as an exclusion criterion. However, there is currently no study examine the safety and characteristics of kidney donors with thalassemia minor.

Methods

All eligible live kidney donors between 2016 and 2019 with thalassemia minor at a tertiary hospital were recruited. Baseline characteristics, clinical and laboratory outcomes were investigated.

Results

Fifteen donors (11 women, 55.5 ± 15.0 year-old) were included with a follow-up duration of 2 (1-4) years since operation. The most prevalent gene mutation among participants was DEL-SEA. No clinical manifestations of anemia were seen but 10 participants had mild anemia diagnosed from blood tests. Cardiovascular, liver and renal function were normal before nephrectomy. Until now, all donors are alive and maintain overall good health. Anemia condition is not affected, and the post-donation eGFR = 71.04 ± 11.54 mL/min/1.73m² is comparable to outcomes of healthy donors reported in previous studies. Two donors are at risk of proteinuria at 1-year post-transplant with A/C ratio > 30 mg/g.

Conclusions

Thalassemia minor individuals who are non-transfusion-dependent, without anemia clinical manifestations and have no contraindications to kidney donation are safe to be donors in short-term. An eGFR of at least 80 mL/min/1.73m² should be considered to avoid low post-donation eGFR, and awareness should be raised on thalassemia donors with even mild albuminuria. Nephrectomy does not worsen thalassemia.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02609-2.

Remnant renal volume can predict prognosis of remnant renal function in kidney transplantation donors: a prospective observational study

Background

Safety and survival during and after donor nephrectomy (DN) are one of the main concerns in living kidney donors (LKDs). Therefore, kidney (left/right) to be procured should be determined after considering the difficulty of DN, as well as the preservation of remnant renal function (RRF). In this prospective study, we investigated the roles of computed tomography volumetry (CTV) in split renal function (SRF) and established a predictive model for RRF in LKDs.

Methods

We assessed 103 LKDs who underwent DN at our institute. The Volume Analyzer SYNAPSE VINCENT image analysis system were used as CTV. RRF was defined as the estimated glomerular filtration rate (eGFR) 12 months after DN. The association between various factors measured by CTV and RRF were investigated, and a role of CTV on prediction for RRF was assessed.

Results

The median age and the preoperative eGFR were 58 years and 80.7 mL/min/1.73m², respectively. Each factor measured by CTV showed an association with RRF. The ratio of remnant renal volume to body surface area (RRV/BSA) could predict RRF. In addition, RRV/BSA could predict RRF more accurately when used together with age and 24-h creatinine clearance (CrCl).

Conclusions

Our findings suggest that RRV/BSA measured by CTV can play an important role in predicting RRF, and a comprehensive assessment including age and CrCl is important to determine the kidney to be procured.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02568-8.

Alterations in the Mineral Bone Metabolism of Living Kidney Donors After Uni-Nephrectomy: Prospective Observational Study

We investigated the dynamic change of mineral bone metabolism and explored factors associated with the alteration of mineral bone metabolism in the living kidney donors (LKDs) after uni-nephrectomy. One-hundred forty-four prospective LKDs who underwent kidney donation between May 2016 and September 2018 were enrolled. Laboratory evaluation regarding mineral bone metabolism including intact parathyroid hormone (iPTH), renal fractional excretion of phosphate (FEPi), and technetium-99m diethylenetriaminepentaacetate (^99mTc-DTPA) scan was performed predonation and 6 months after donation. We divided donors into two groups, the low ΔFEPi and high ΔFEPi groups, according to the change of FEPi after donation, and investigated significant risk factors associated with high ΔFEPi. At 6 months after uni-nephrectomy, estimated glomerular filtration rate (eGFR) significantly declined by 30.95 ml/min/1.73 m² (p < 0.001), but the measured GFR (mGFR) of the remaining kidney by ^99mTc-DTPA scan showed significant increase. Serum phosphorus decreased (p < 0.001), whereas FEPi (13.34–20.23%, p < 0.001) and serum iPTH (38.70–52.20 pg/ml, p < 0.001) showed significant increase. In the high ΔFEPi group, the proportion of preexisting hypertension (HTN) was higher, the baseline FEPi was lower, and the percent decline in eGFR was greater. Moreover, all of these factors were independently associated with high ΔFEPi upon multivariable logistic regression analysis. LKDs showed a significant change in mineral bone metabolism after uni-nephrectomy, especially when the donors had preexisting HTN, lower baseline FEPi, and showed greater loss of kidney function. Hence, strict monitoring of the mineral bone metabolism parameters and bone health may be required for these donors.

External Validation of a Predictive Model to Estimate Renal Function After Living Donor Nephrectomy

BACKGROUND

Transplantation from living donor nephrectomy (LDN) is the best treatment for end-stage renal disease but observed decrease in donor renal function is a major concern. The aim of this study was to externally validate a predictive model to estimate 1-y postdonation estimated glomerular filtration rate (eGFR) and risk of chronic kidney disease (CKD) in living donors.

METHODS

All LDN performed at Necker Hospital from January 2006 to May 2018 were retrospectively included. Observed eGFR (using CKD-EPI formula) at 1-y post LDN was compared with the predicted eGFR calculated with a formula developed at Toulouse-Rangueil and based on predonation eGFR and age. Pearson correlation, receiver operating characteristics curve (ROC curve), and calibration curve were used to assess external validity of the proposed prognostic model to predict postoperative eGFR and occurrence of CKD in donors.

RESULTS

Four hundred donors were evaluated with a mean postoperative eGFR of 62.1 ± 14 mL/min/1.73m2. Significant correlation (Pearson r = 0.66; P < 0.001) and concordance (Bradley-Blackwood F = 49.189; P < 0.001) were observed between predicted and observed 1-y eGFR. Area under the receiver operating characteristic curve of the model relevant accuracy was 0.86 (95% CI, 0.82-0.89).

CONCLUSIONS

This study externally validated the formula to predict 1-y postdonation eGFR. The calculator could be an accurate tool to improve the selection of living kidney donor candidate.

Clinical Impact of Subclinical Interstitial Fibrosis or Tubular Atrophy in 1-Hour Allograft Biopsy for Remnant Renal Function in Living Kidney Donors: A Prospective Observational Study

BACKGROUND

Preservation of remnant renal function (RRF) is one of the major concerns among living kidney donors (LKDs). A comprehensive assessment is needed to predict the RRF. In this prospective study, we investigated the roles of histologic findings from a 1-hour allograft biopsy in predicting the RRF.

METHODS

Our prospective study included 116 LKDs who underwent donor nephrectomy (DN) at our institute. Clinical and radiographic data were obtained from their medical charts. Renal volume parameters were calculated using the preoperative computed tomographic images in the volume analyzer SYNAPSE VINCENT image analysis system. Tissues obtained from allograft biopsy were examined. RRF was defined as the estimated glomerular filtration rate (eGFR) 12 months after DN.

RESULTS

Of 116 LKDs, 95 were finally evaluated. The median age of the LKDs at DN and the preoperative eGFR were 57 years and 80.0 mL/min/1.73 m², respectively. In the histologic analysis, 68 allografts (71.6%) had nonspecific findings involving the glomerulus, vessel, and tubulointerstitium. Interstitial fibrosis or tubular atrophy (IF/TA) was the only significant predictive factor for RRF (P = .039). No significant association was found between renal volume parameters and IF/TA, whereas remnant renal volume adjusted by body weight (RRV/BW) tended to be relatively correlated with IF/TA (P = .072). Furthermore, LKDs with subclinical IF/TA tended to have decreased RRV/BW compared with those without subclinical IF/TA (P = .088).

CONCLUSIONS

Our findings suggested that the presence of IF/TA could be a predictive factor for RRF after DN. Further research establishing the predictive model for RRF is warranted to improve the outcomes of LKDs.

Critical timing of ACEi initiation prevents compensatory glomerular hypertrophy in the remaining single kidney

Increasing evidence suggests that single in kidney states (e.g., kidney transplantation and living donation) progressive glomerulosclerosis limits kidney lifespan. Modeling shows that post-nephrectomy compensatory glomerular volume (GV) increase drives podocyte depletion and hypertrophic stress resulting in proteinuria and glomerulosclerosis, implying that GV increase could serve as a therapeutic target to prevent progression. In this report we examine how Angiotensin Converting Enzyme inhibition (ACEi), started before uninephrectomy can reduce compensatory GV increase in wild-type Fischer344 rats. An unbiased computer-assisted method was used for morphometric analysis. Urine Insulin-like growth factor-1 (IGF-1), the major diver of body and kidney growth, was used as a readout. In long-term (40-week) studies of uni-nephrectomized versus sham-nephrectomized rats a 2.2-fold increase in GV was associated with reduced podocyte density, increased proteinuria and glomerulosclerosis. Compensatory GV increase was largely prevented by ACEi started a week before but not after uni-nephrectomy with no measurable impact on long-term eGFR. Similarly, in short-term (14-day) studies, ACEi started a week before uni-nephrectomy reduced both GV increase and urine IGF-1 excretion. Thus, timing of ACEi in relation to uni-nephrectomy had significant impact on post-nephrectomy "compensatory" glomerular growth and outcomes that could potentially be used to improve kidney transplantation and live kidney donation outcomes.

Outcomes of Living Kidney Donor Candidates and Living Kidney Recipient Candidates with JC Polyomavirus and BK Polyomavirus Viruria

Introduction

Recent data have emerged about a protective association between JCV viruria and chronic kidney disease (CKD). Material and Methods. Single-center retrospective cohort study; 230 living kidney donors (LKD) candidates and 59 potential living kidney receptors (LKR) were enrolled. Plasma and urinary JCV and BKV viral loads were measured in all LKD candidates and in nonanuric LKR candidates. Twenty-six living kidney transplant surgeries were performed. LKR were followed in order to evaluate BKV and JCV viremia and urinary viral shedding after KT.

Results

In LKD candidates, JCV viruria was negatively associated with proteinuria of >200 mg/24 hours (JC viruric LKD: 12.5% vs JCV nonviruric LKD: 26.7%, p=0.021, OR:0.393; 95% CI: 0.181–0.854). In a multivariate analysis, LKD candidates with JCV viruria had a lower risk of proteinuria of >200 mg/24 hours (p=0.009, OR: 0.342, 95% CI: 0.153–0.764), in a model adjusted for age, gender, presence of hypertension, and eGFR <80 mL/min. Prevalence of JCV viruria was higher in LKD candidates when compared with LKR candidates (40.0% vs 1.7%, p < 0.001). Among the 26 LKR, 14 (53.8%) KT patients evolved with JCV viruria; 71.4% received a graft from a JCV viruric donor.

Conclusion

Our data corroborate the recent findings of an eventual protective association between JCV viruria and kidney disease, and we extrapolated this concept to a South European population.

Organ-Specific Monitoring of Solitary Kidney after Living Donation by Using Markers of Glomerular Filtration Rate and Urinary Proteins

BACKGROUND

Effective follow-up after living kidney donation is important for maintaining the renal function of the donor. We investigated whether the estimated glomerular filtration rate (eGFR) and urinary protein and enzyme levels can provide important information regarding the state of the remaining kidney after donor nephrectomy.

METHODS

Seventy-five living donations were included (prospective/retrospective) in the study. The following parameters were measured up to 1 year after donor nephrectomy: serum creatinine and cystatin C as markers of the GFR; the high-molecular-weight urinary proteins as markers of glomerular injury; and the low-molecular-weight urinary proteins and urinary enzymes as markers of tubular function.

RESULTS

One year after kidney donation, the creatinine and cystatin C values were 1.38-fold increased than their initial values, while the eGFR was 32% lower. At that time, 38% of donors had a moderate or high risk of CKD progression. The biochemical urinary glomerular and tubular kidney markers examined showed different behaviors. After a transient increase, the glomerular proteins normalized. Conversely, the detection of low-molecular-weight urinary proteins and enzymes reflected mild tubular damage at the end of the study period.

CONCLUSIONS

Our findings suggest that for the evaluation of mild tubular damage, low-molecular-weight marker proteins should be included in the urine diagnostic of a personalized living kidney donor follow-up.

Have we reached the limits in altruistic kidney donation?

Altruistic donation (unspecified donation) is an important aspect of living donor kidney transplantation. Although donation to a stranger is lawful and supported in many countries, it remains uncommon and not actively promoted. Herein, we ask the question if we have reached the limit in altruistic donation. In doing so, we examine important ethical questions that define the limits of unspecified donation, such as the appropriate balance between autonomous decision-making and paternalistic protection of the donor, the extent of outcome uncertainty and risk-benefit analyses that donors should be allowed to accept. We also consider the scrutiny and acceptance of donor motives, the potential for commercialization, donation to particular categories of recipients (including those encountered through social media) and the ethical boundaries of active promotion of unspecified kidney donation. We conclude that there is scope to increase the number of living donation kidney transplants further by optimizing existing practices to support and promote unspecified donation. A number of strategies including optimization of the assessment process, innovative approaches to reach potential donors together with reimbursement of expenses and a more specific recognition of unspecified donation are likely to lead to a meaningful increase in this type of donation.

Long-term mortality of living kidney donors: a systematic review and meta-analysis

BACKGROUND

To date, several studies have reported inconsistent findings regarding the mortality risk faced by living kidney donors and controls. Our study assessed the methodological quality of previous studies and performed an updated meta-analysis of the mortality risk.

METHODS

Comprehensive literature searches were conducted involving the PubMed, Embase, and Cochrane databases through September 2020. The search terms used included 'living donor' and 'kidney transplantation' and 'kidney donor' and 'mortality' or 'death' or 'survival'. We evaluated the risk of bias in such studies using ROBINS-I tool. Mortality risk was analyzed using OR and HR.

RESULTS

The qualitative review involved 18 studies and the meta-analysis included nine studies. We identified 3 studies with an overall risk of bias rated as "Low", 2 studies rated as "Moderate", 8 studies rated as "Serious", and 5 studies rated as "Critical". The pooled overall mortality risk in the meta-analysis was 0.984 (95% CI: 0.743, 1.302). In the subgroup analysis of HR and OR, the summary effect estimates did not reach statistical significance. The meta-regression analysis revealed that the donor group of more than 60,000 (1.836, 95% CI: 0.371, 6.410) carried a significantly high mortality risk compared with the donor group of less than 60,000 (0.810, 95% CI: 0.604, 1.086) (P = 0.007). The number of total patients was associated with slightly elevated mortality risks (0.796 for < 10,000, 0.809 for 10,000-60,000, and 1.852 for > 60,000; P < .054).

CONCLUSIONS

Current evidence based on this systematic review suggests that the methodology of previous studies was inconsistent and also carried a high risk in several aspects. Updated meta-analysis showed that the mortality risk was not significantly different. Future studies with well-designed methodology are necessary.

Is the risk of cardiovascular disease increased in living kidney donors? A Danish population-based cohort study

Reduced renal function is associated with cardiovascular disease (CVD); however, how living donor nephrectomy affects the risk of CVD remains controversial. We conducted a nationwide cohort study including living kidney donors in Denmark from 1996 to 2018 to assess the risk of hypertension, atrial fibrillation/flutter (AF), major adverse cardiovascular events (MACE; composite of myocardial infarction, ischemic stroke, and death) and death after living kidney donation. As comparisons we identified: a cohort of healthy individuals from the general population and an external blood donor cohort. We followed kidney donors (1,103 when compared with the general population cohort; 1,007 when compared with blood donors) for a median of 8 years. Kidney donors had an increased risk of initiating treatment for hypertension when compared with blood donors (standardized incidence ratio [SIR], 1.40; 95% confidence interval [CI], 1.17-1.66) but they did not have increased risk of MACE neither when compared with the general population cohort (hazard ratio, 0.68; 95% CI, 0.52-0.89) nor with blood donors (SIR, 1.17; 95% CI, 0.88-1.55). Neither did they have increased risks of AF and death. Thus, living kidney donation may be associated with increased risk of hypertension; however, we did not identify increased risks of CVD or death.

Changes in renal function and predictors affecting renal outcome of living kidney donors: a nationwide prospective cohort study

AIM

The safety of donors is an important issue in living donor kidney transplantation. We investigated serial changes in renal function and predictors affecting the renal outcome of living kidney donors.

METHODS

We obtained the data of 456 kidney donors registered to the Korean Organ Transplantation Registry from 2014 to 2016. The estimated glomerular filtration rate (eGFR) changes according to the development of incident chronic kidney disease (CKD) and factors related to CKD were analysed. CKD was defined as an eGFR <60 ml/min/1.73 m² or the presence of proteinuria or albuminuria. The change in eGFR over time was analysed using a linear mixed model.

RESULTS

At 2 years after kidney donation, 21.7% of the donors (99/456) developed CKD. Annual eGFR changes after nephrectomy were 2.2 ml/min/1.73 m² /year in donors without CKD, and - 0.4 ml/min/1.73 m² /year in donors with CKD. Higher systolic blood pressure was associated with higher risk of CKD (odds ratio [OR] 1.322 per 10 mmHg increment, 95% confidence interval [CI] 1.036-1.686, p = .025). Higher pre-donation eGFR (OR 0.906 per 1 ml/min/1.73 m² increment, 95% CI 0.876-0.936, p < .001) and higher ratio of eGFR at discharge to pre-donation (OR 0.603 per 0.1 increment, 95% CI 0.426-0.849, p = .004) were related to lower risk of CKD.

CONCLUSION

Kidney donors without incident CKD at 2 years after donation showed gradual increases in eGFR, whereas donors with CKD had relatively constant eGFR. A low ratio of eGFR at discharge after nephrectomy to baseline was a risk factor of CKD.

Increased risk of ischemic heart disease after kidney donation

Background

Previous reports suggest increased risk of hypertension and cardiovascular mortality after kidney donation. In this study we investigate the occurrence of ischaemic heart disease and cerebrovascular disease, diabetes and cancer in live kidney donors compared with healthy controls eligible for donation.

Methods

Different diagnoses were assessed in 1029 kidney donors and 16 084 controls. The diagnoses at follow-up were self-reported for the controls and registered by a physician for the donors. Stratified logistic regression was used to estimate associations with various disease outcomes, adjusted for gender, age at follow-up, smoking at baseline, body mass index at baseline, systolic blood pressure at baseline and time since the donation.

Results

The mean observation time was 11.3 years [standard deviation (SD) 8.1] for donors versus 16.4 years (SD 5.7) for controls. The age at follow-up was 56.1 years (SD 12.4) in donors versus 53.5 years (SD 11.1) in controls and 44% of donors were males versus 39.3% in the controls. At follow-up, 35 (3.5%) of the donors had been diagnosed with ischaemic heart disease versus 267 (1.7%) of the controls. The adjusted odds ratio for ischaemic heart disease was 1.64 (confidence interval 1.10–2.43; P = 0.01) in donors compared with controls. There were no significant differences for the risks of cerebrovascular disease, diabetes or cancer.

Conclusions

During long-term follow-up of kidney donors, we found an increased risk of ischaemic heart disease compared with healthy controls. This information may be important in the follow-up and selection process of living kidney donors.

Long-term risks after kidney donation: how do we inform potential donors? A survey from DESCARTES and EKITA transplantation working groups

Background

Publications from the last decade have increased knowledge regarding long-term risks after kidney donation. We wanted to perform a survey to assess how transplant professionals in Europe inform potential kidney donors regarding long-term risks. The objectives of the survey were to determine how they inform donors and to what extent, and to evaluate the degree of variation.

Methods

All transplant professionals involved in the evaluation process were considered eligible, regardless of the type of profession. The survey was dispatched as a link to a web-based survey. The subjects included questions on demographics, the information policy of the respondent and the use of risk calculators, including the difference of relative and absolute risks and how the respondents themselves understood these risks.

Results

The main finding was a large variation in how often different long-term risks were discussed with the potential donors, i.e. from always to never. Eighty percent of respondents stated that they always discuss the risk of end-stage renal disease, while 56% of respondents stated that they always discuss the risk of preeclampsia. Twenty percent of respondents answered correctly regarding the relationship between absolute and relative risks for rare outcomes.

Conclusions

The use of written information and checklists should be encouraged. This may improve standardization regarding the information provided to potential living kidney donors in Europe. There is a need for information and education among European transplant professionals regarding long-term risks after kidney donation and how to interpret and present these risks.

Factors Associated With Residual Kidney Function and Proteinuria After Living Kidney Donation in the United States

BACKGROUND

Living kidney donors are carefully screened, but despite overall good health, long-term donor outcomes have been shown to vary by predonation demographics. Since 2013, the United Network for Organ Sharing has mandated 2-year postdonation follow-up with measurements of kidney function and proteinuria.

METHODS

Using data from the Scientific Registry of Transplant Recipients, we sought to analyze donor factors associated with the percent change of kidney function from baseline (predonation) to 2-year postdonation, along with incidence of proteinuria reported within the same follow-up period.

RESULTS

Older donor age, male gender, black race, and body mass index >25 kg/m2 were independently associated with a greater percent decline in estimated glomerular filtration rate (eGFR). Male gender, black race, and higher body mass index were also independently associated with incident proteinuria. In contrast, younger donor age was associated with proteinuria, but proteinuria did not correlate with greater decline in eGFR in the overall cohort.

CONCLUSIONS

Donor factors associated with lower eGFR at 2-year postdonation were similar to those previously found to be associated with long-term risk for end-stage renal disease. Early postdonation assessment of kidney function and proteinuria may help to identify donors who are at greater risk of end-stage renal disease and who may benefit from more intense long-term monitoring.

Kidney Microstructural Features at the Time of Donation Predict Long-term Risk of Chronic Kidney Disease in Living Kidney Donors

OBJECTIVE

To determine whether microstructural features on a kidney biopsy specimen obtained during kidney transplant surgery predict long-term risk of chronic kidney disease in the donor.

PATIENTS AND METHODS

We studied kidney donors from May 1, 1999, through December 31, 2018, with a follow-up survey for the results of recent blood pressure and kidney function tests (estimated glomerular filtration rate [eGFR] and proteinuria). If not recently available, blood pressure and eGFRs were requested from a local clinic. Microstructural features on kidney biopsy at the time of donation were assessed as predictors of hypertension and kidney function after adjusting for years of follow-up, baseline age, sex, and clinical predictors.

RESULTS

There were 807 donors surveyed a mean 10.5 years after donation. An eGFR less than 45 mL/min/1.73 m2 in 6.4% (43/673) of donors was predicted by larger glomerular volume per standard deviation (odds ratio [OR], 1.48; 95% CI, 1.08 to 2.04) and nephron number below the age-specific 5th percentile (OR, 3.38; 95% CI, 1.31 to 8.72). An eGFR less than 60 mL/min/1.73 m2 in 42.5% (286/673) of donors was not predicted by any microstructural feature. Residual eGFR (postdonation/predonation eGFR) was predicted by nephron number below the age-specific 5th percentile (difference, -6.07%; 95% CI, -10.24% to -1.89%). Self-reported proteinuria in 5.1% (40/786) of donors was predicted by larger glomerular volume (OR, 1.42; 95% CI, 1.08 to 1.86). Incident hypertension in 18.8% (119/633) of donors was not predicted by any microstructural features.

CONCLUSION

Low nephron number for age and larger glomeruli are important microstructural predictors for long-term risk of chronic kidney disease after living kidney donation.

Study of Glomerulopathy in Donors after Kidney Transplantation

INTRODUCTION

Living kidney donation improves the lives of individuals with kidney failure; however, recent studies have suggested that living kidney donors may be at a relatively higher risk of reduced renal function than healthy non-donors. We therefore aimed to evaluate the clinical and pathological findings in living kidney donors who developed kidney disease.

METHODS

From January 1991 to May 2019, 1,625 live kidney donations were performed at our hospital. Among the donors, 7 developed kidney disease after donation and underwent open renal biopsy. We studied the clinical and pathological findings of these patients from their clinical records.

RESULTS

There were 3 patients with immunoglobulin A (IgA) nephropathy, 2 with membranous nephropathy, 1 with anti-neutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis, and 1 with secondary focal segmental glomerulosclerosis (FSGS). All patients with IgA nephropathy had latent IgA deposition on their baseline biopsy. One patient with membranous nephropathy demonstrated findings of membranous nephropathy on the baseline biopsy, despite being asymptomatic. All patients, except for those with ANCA-associated nephropathy and secondary FSGS, recovered from the nephritis or maintained an adequate renal function after treatment.

DISCUSSION/CONCLUSION

Baseline biopsy is necessary for assessing the renal condition of kidney donors, and these donors require long-term follow-up based on their baseline biopsy findings. If donors develop kidney disease, appropriate diagnosis and treatment are essential.

How Does the Remaining Single Kidney Cope After Contralateral Nephrectomy of the Kidney Donor? A Single-Center Cohort Study

Introduction

Immediately after kidney donation, the remaining kidney will undergo hyperfiltration and work at a higher level to compensate for the other kidney's loss. It is estimated that 70% of the baseline renal function before the donation is recovered post-donation. However, factors that determine the post-donation renal compensation are not well understood.

Methods

We conducted a retrospective study of 190 consecutive kidney donors who completed a one-year follow-up in order to predict the factors affecting the function of the remaining kidney post-contralateral nephrectomy.

Results

We enrolled 190 living kidney donors who had completed at least one year of follow-up after nephrectomy. Among the participants, 149 (78.4%) were males and 41 (21.6%) were females. The mean age of the participants was 31.33 ±7.9 years and the mean body mass index (BMI) was 25.6 ±3.9 kg/m². Before kidney donation, the mean estimated glomerular filtration rate (eGFR) and serum creatinine were 114.31 ±15.94 ml/min/1.73 m² and 71.60 ±10.62 mmol/min, respectively. At the one-year follow-up, the mean eGFR was 77.97 ±14.44 ml/min/1.73 m² and serum creatinine was 100.84 ±20.15 mmol/min. The female gender [odds ratio (OR): 20.6, 95% CI: 3.9-107.7, p: <0.001] and having a higher baseline eGFR (OR: 8.8, 95% CI: 1.6-45.8, p = 0.01) were found to be significant predictors of having a better eGFR at one year post-nephrectomy.

Conclusions

Female gender and pre-donation low serum creatinine and high eGFR were the significant predictors of better kidney function at one year post-contralateral nephrectomy. However, further studies with longer follow-up durations are needed to better assess the factors that could predict renal compensation and the renal compensation rate's suitability as a prognostic measure for long-term renal outcomes.

Pediatric Donor Glomerulopathy Is a Possible Cause of Abnormal Urinalysis in Adults Receiving Small Pediatric Donor Kidneys

Background.

Reports about prognosis of adults receiving small pediatric-donor kidneys (PDK) as compared to those receiving elder pediatric or adult donor kidneys (ADKs) are controversial. This study aimed to examine the outcomes of adults receiving small PDK and possible prognostic factors.

Methods.

The records of adults who received kidneys from donors < 10 years old at our center from July 1, 2011 to June 30, 2018 were reviewed.

Results.

A total of 121 adults were small PDK recipients. Twenty-three patients received 29 biopsies or nephrectomy between 6 and 896 days posttransplantation days. Seven patients (30.4%) had pediatric donor glomerulopathy (PDG), which developed from 113 to 615 days posttransplantation. The incidence of proteinuria and hematuria was significantly higher in the PDG group. The characteristic pathological finding in PDG was irregular lamination and splintering of the glomerular basement membrane (GBM). Donor age, donor weight, and donor kidney volume were significantly less in PDG cases compared with the non-PDG cases. For the risk factors of PDG, increasing urinary RBC count during follow-up was an independent predictor, while increasing donor age and body weight were protective factors. PDG was not a significant risk factor for Scr increasing of PDKs.

Conclusions.

PDG is a potential cause of abnormal urinalysis in adults receiving small PDKs. The pathological characteristic change of PDG is splitting and lamination of GBM. Persistent hematuria after transplantation in recipients of PDK is a predictor of PDG development.

Safe Long-Term Outcome After Kidney Donation in Older Donors: A Single-Center Experience

Background

Declining numbers of deceased donors and prolonged waiting time emphasize the importance of living kidney donation. Furthermore, because of the changing age structures with increasingly older recipients, the question of acceptance of older donors is becoming more relevant. However, sufficient long-term outcome data, especially for older donors – including histopathological analysis – are lacking. The aim of this study was to analyze the Regensburg Living Donor Cohort with regard to age <65 and ≥65 years, with a 10-year follow-up to identify attributable risk factors.

Material/Methods

All donors were analyzed for renal, cardiovascular, and pre-existing conditions at baseline and at follow-up. They were studied for predefined renal and additional end-points, eg cardiovascular ones and various stratifications such as estimated glomerular filtration rate (eGFR). Additionally, as a unique feature in such an analysis, a histopathological workup of pre-existing chronic lesions of the donated kidneys was added.

Results

On average, donors in the group <65 years were 50 years old at the time of donation compared with 68 years in the older group. Creatinine at baseline was 0.8 mg/dl in both groups, corresponding to an eGFR of 96.8±12.8 ml/min (Chronic Kidney Disease Epidemiology Collaboration [CKD-EPI]) and 83.7±10.3 ml/min (CKD-EPI). In the follow-up, donors ≥65 years showed a statistically significantly worse eGFR and a greater eGFR decline, being accompanied by more pronounced chronic histopathological lesions, eg glomerulopathy, than the control group. However, this was largely constant over the entire observation period and no donor developed an end-stage renal disease or an eGFR below 30 ml/min.

Conclusions

To summarize, living kidney donation after an intensive screening is safe even for older donors; however, a precise aftercare to ensure balanced risk profile for living donors is mandatory.

The Alteration of Pro-inflammatory Cytokines and Oxidative Stress Markers at Six-Month Post-living Kidney Donation

Donors have a higher risk of developing chronic kidney disease than the general population. Some mechanisms mediated by pro-inflammatory cytokines and oxidative stress may be involved as risk factors. The objective of the study was to evaluate the behavior of pro-inflammatory cytokines and oxidative stress markers in living renal donors with a 6-month follow-up. A single prospective cohort was performed in 88 renal donors. At the end of the follow-up, the levels of lipoperoxides, 6.52 ± 1.12 mM, and 8-isoprostanes, 63.75 ± 13.28 pg/mL, were lower than before donation, 10.20 ± 3.95 mM (p < 0.001) and 67.54 ± 9.64 pg/mL (p = 0.026), respectively. Initial levels of nitric oxide (NO), 356.09 ± 59.38 μM increased at the end of the follow-up, 467.08 ± 38.74 μM (p < 0.001). It was observed in the final determination of donors decreased activity of antioxidant enzymes superoxide dismutase (SOD), 0.74 ± 0.57 U/L and glutathione peroxidase (GPx), 556.41 ± 80.37 nmol, in comparison with the levels obtained in the initial determination, 1.05 ± 0.57 U/L (p < 0.001) and 827.93 ± 162.78 nmol (p < 0.001), respectively. The pro-inflammatory cytokines, Tumor necrosis factor alpha and interleukin-6 showed no differences at 6 months after donation. The enzyme oxoguanine glycosylase (hOGG1) responsible for repairing oxidative damage to DNA, showed a decrease in its concentration at the end of the study in donor men, 0.40 ± 0.21 ng/mL compared to the initial levels, 0.55 ± 0.32 ng/mL (p = 0.025). The marker, 8-hydroxy-2-deoxyguanosine (8-OHdG) exhibited an increase in donor men at the final determination 2.28 ± 1.99 ng/mL, compared to the concentration before donation, 1.72 ± 1.96 ng/mL (p < 0.001). We found significant changes in the markers of the oxidative state with increased NO and 8-OHdG, as well as a significant decrease in the antioxidant defenses SOD, GPx, and in the DNA repair enzyme in living renal donors after 6 months of follow-up.

Long-term compensation of renal function after donor nephrectomy

Background

Living donors are the major source of kidneys in countries with a shortage of deceased donors. Kidney donation after careful donor selection is generally accepted as a safe procedure, but the physiologic consequences after donor nephrectomy are not fully verified. In this study we retrospectively reviewed the renal function of the residual kidney in living donors.

Methods

Post-nephrectomy laboratory data of 1,175 living donors (60.7%) from 1,933 living donors who received uninephrectomy from January 1999 to December 2017 at Yonsei University, Severance Hospital, Korea were retrospectively collected. Post-nephrectomy renal function was monitored by the relative ratio of estimated glomerular filtration rate (e-GFR; pre-nephrectomy e-GFR ratio vs. post-nephrectomy e-GFR) that was calculated by the Modification of Diet in Renal Disease formula.

Results

During 36.3±37.6 months of mean follow-up, two cases (0.17%, 2/1,175) of renal failure developed. The mean e-GFR decreased to 64.3±14.2 mL/min/1.73 m² immediately after nephrectomy from 99.2±19.9 mL/min/1.73 m² of the pre-nephrectomy e-GFR. Early decrement of e-GFR was prominent in male and obese donors (body mass index >25 kg/m², P<0.05). The e-GFR ratio increased according to post-nephrectomy duration, and the mean increment degree of e-GFR ratio after nephrectomy calculated by linear regression analysis was 1.94% per year. Unlike the early decrement of e-GFR ratio after nephrectomy, donor factors such as degree of obesity and donor sex did not affect the late increment of e-GFR ratio after nephrectomy (P>0.05).

Conclusions

Our data showed that long-term compensation of the renal function after nephrectomy occurs independently of preoperative donor characteristics.

Changes in kidney function follow living donor nephrectomy

Better understanding of kidney function after living donor nephrectomy and how it differs by donor characteristics can inform patient selection, counselling, and follow-up care. To evaluate this, we conducted a retrospective matched cohort study of living kidney donors in Alberta, Canada between 2002-2016, using linked healthcare administrative databases. We matched 604 donors to 2,414 healthy non-donors from the general population based on age, sex, year of cohort entry, urban residence and the estimated glomerular filtration rate (eGFR) before cohort entry (nephrectomy date for donors and randomly assigned date for non-donors). The primary outcome was the rate of eGFR change over time (median follow-up seven years; maximum 15 years). The median age of the cohort was 43 years, 64% women, and the baseline (pre-donation) eGFR was 100 mL/min/1.73 m². Overall, from six weeks onwards, the eGFR increased by +0.35 mL/min/1.73 m² per year (95% confidence interval +0.21 to +0.48) in donors and significantly decreased by -0.85 mL/min/1.73 m² per year (-0.94 to -0.75) in the matched healthy non-donors. The change in eGFR between six weeks to two years, two to five years, and over five years among donors was +1.06, +0.64, and -0.06 mL/min/1.73 m² per year, respectively. In contrast to the steady age-related decline in kidney function in non-donors, post-donation kidney function on average initially increased by 1 mL/min/1.73 m² per year attributable to glomerular hyperfiltration, which began to plateau by five years post-donation. Thus, the average change in eGFR over time is significantly different between donors and non-donors.

Living Kidney Donor Evaluation

Long-term safety of living kidney donation (LKD), especially for young donors, has become a real matter of concern in the transplant community and may contribute to creating resistance to LKD. In this context, the criteria that govern living donor donations must live up to very demanding standards as well as adjust to this novel reality. In the first part, we review the existing guidelines published after 2010 and critically examine their recommendations to see how they do not necessarily lead to consistent and universal practices in the choice of specific thresholds for a parameter used to accept or reject a living donor candidate. In the second part, we present the emergence of a new paradigm for LKD developed in the 2017 Kidney Disease: Improving Global Outcomes guidelines with the introduction of an integrative risk-based approach. Finally, we focus on predonation renal function evaluation, a criteria that remain central in the selection process, and discuss several issues surrounding the donor candidate's glomerular filtration rate assessment.