Long-term Medical Outcomes of Living Kidney Donors

Living Kidney Donation: A Narrative Review of Mid- and Long-term Psychosocial Outcomes

Living kidney donors make a significant contribution to alleviating the organ shortage. The aim of this article is to provide an overview of mid- and long-term (≥12 mo) living donor psychosocial outcomes and highlight areas that have been understudied and should be immediately addressed in both research and clinical practice. We conducted a narrative review by searching 3 databases. A total of 206 articles were included. Living donors can be divided into those who donate to an emotionally or genetically related person, the so-called directed donors, or to an emotionally or genetically unrelated recipient, the so-called nondirected donors. The most commonly investigated (bio)psychosocial outcome after living donation was health-related quality of life. Other generic (bio)psychological outcomes include specific aspects of mental health such as depression, and fatigue and pain. Social outcomes include financial and employment burdens and problems with insurance. Donation-specific psychosocial outcomes include regret, satisfaction, feelings of abandonment and unmet needs, and benefits of living kidney donation. The experience of living donation is complex and multifaceted, reflected in the co-occurrence of both benefits and burden after donation. Noticeably, no interventions have been developed to improve mid- or long-term psychosocial outcomes among living donors. We highlight areas for methodological improvement and identified 3 areas requiring immediate attention from the transplant community in both research and clinical care: (1) recognizing and providing care for the minority of donors who have poorer long-term psychosocial outcomes after donation, (2) minimizing donation-related financial burden, and (3) studying interventions to minimize long-term psychosocial problems.

Living Donor Nephrectomy: Analysis of Trends and Outcomes From a Contemporary National Dataset

OBJECTIVE

To analyze the temporal trends and perioperative and long-term outcomes of living donor kidney nephrectomy in the United States.

METHODS

The PearlDiverTM Mariner database (Pearl-Diver Technologies, Colorado Springs, CO, USA) was used for our retrospective analysis. The data were identified using ICD-9/10 codes, as well as CPT codes. Continuous and categorical variables were compared using 2-sided tests. Multivariate logistic regression analysis was conducted to identify predictors of 5-year ESRD.

RESULTS

A total of 6333 patients were identified (median age 54, IQR 46-62 years) from 2010 to April 2022. A greater percentage of living donor nephrectomies were performed by general surgeons (56.1%), followed by transplant surgeons (16.5%) and urologists (14.7%). Unfortunately, physician specialty was not reported for the remaining patients. The MIS exceeded open surgery in each specialty group and inpatient setting. The significant predictors of ESRD were male, preoperative DM and hypertension, tobacco smoking, perioperative AKI and younger age at the time of kidney donation.

CONCLUSION

MIS represents the main surgical approach for organ procurement. A meticulous selection process for donors and subsequent close monitoring are necessary to minimize the putative consequences of donor nephrectomy.

Aortic stiffness after living kidney donation: a systematic review and meta-analysis

OBJECTIVES

Increased aortic stiffness measured with carotid-femoral pulse wave velocity (cf-PWV) has been associated with adverse cardiovascular outcomes. Some studies have reported increased cf-PWV in living kidney donors after nephrectomy. This review aimed to determine the effects of living kidney donation on cf-PWV, glomerular filtration rate (GFR), systolic blood pressure (SBP), diastolic blood pressure (DBP) and their differences versus non-nephrectomised healthy individuals.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Electronic databases (MEDLINE, EMBASE, Cochrane Central databases, Cochrane Register of Controlled Trials, Cochrane Methodology Register, Health Technology Database, Technologies in Health, EBM Reviews, ProQuest and 'Grey Matters Light'). Databases were searched from inception to December 2022.

ELIGIBILITY CRITERIA

We searched for studies that measured cf-PWV in living kidney donors before and/or after nephrectomy. Non-nephrectomised healthy individuals included as controls were the comparators. Studies that provided age-adjusted cf-PWV reference values in normotensive healthy individuals were also included.

OUTCOME MEASURES

We evaluated the mean differences in cf-PWV, GFR and BP before-and-after nephrectomy and their mean differences versus non-nephrectomised healthy comparators. We also explored differences in yearly adjusted cf-PWV changes between donors and normotensive healthy individuals.

DATA EXTRACTION/SYNTHESIS

Two independent reviewers extracted data and assessed risk of bias (Risk of Bias tool for non-Randomised studies: ROBINS-I) and quality of evidence (GRADE). Pooled effect estimates were calculated using the inverse variance method and analysed with random effect models.

RESULTS

Nine interventional (652 donors; 602 controls) and 6 reference studies (6278 individuals) were included. cf-PWV increased at 1-year postdonation (p=0.03) and was on average 0.4 m/s (95% CI 0.07; 0.60) higher than in healthy controls (p=0.01). These differences were non-significant 5 years postnephrectomy (p=0.54). GFR decreased after nephrectomy (p<0.001) and remained reduced compared with healthy controls (p<0.001), but SBP and DBP were not significantly different (p≥0.14). Yearly changes in cf-PWV postnephrectomy were similar to age-adjusted reference values in healthy normotensive individuals (p=0.76).

CONCLUSIONS

Aortic stiffness increases independent of BP 1 year after kidney donation, but the long-term effects seem minimal. These findings may impact future consent of prospective living kidney donors.

PROSPERO REGISTRATION NUMBER

CRD42020185551.

Potassium-Alkali-Enriched Diet, Hypertension, and Proteinuria following Uninephrectomy

Key Points

A K-alkali–enriched diet blunted post-uninephrectomy hypertension and facilitated acid clearance by suppressing Na+ reabsorption. Uninephrectomy-associated proteinuria could be attributed to elevated single-nephron GFR and downregulation of megalin, which reduced fractional protein endocytosis.

Background

Losing or donating a kidney is associated with risks of developing hypertension and albuminuria. Few studies address mechanisms or interventions. We investigate the potential benefits of a K+- alkali–enriched diet and the mechanisms underlying proteinuria.

Methods

Male Sprague Dawley rats were fed either a 2% NaCl+0.95% KCl diet (HNa-LK) or a 0.74% NaCl+3% K+-alkali diet (HK-alk) for 3 weeks before uninephrectomy and then maintained on respective diets for 12 weeks. BP (by tail-cuff), urine, blood, and kidney proteins were analyzed before and after uninephrectomy.

Results

Before uninephrectomy, HK-alk–fed versus HNa-LK–fed rats exhibited similar BPs and plasma [K+], [Na+], but lower proximal (NHE3, sodium bicarbonate cotransporter 1, NaPi2) and higher distal (NCC, ENaC, and pendrin) transporter abundance, a pattern facilitating K+ and HCO3− secretion. After uninephrectomy, single-nephron GFR increased 50% and Li+ clearance doubled with both diets; in HK-alk versus HNa-LK, the increase in BP was less and ammoniagenesis was lower, abundance of proximal tubule transporters remained lower, ENaC-α fell, and NCCp increased, consistent with K+ conservation. After uninephrectomy, independent of diet, albuminuria increased eight-fold and abundance of endocytic receptors was reduced (megalin by 44%, disabled homolog 2 by 25%–35%) and kidney injury molecule-1 was increased.

Conclusions

The K-alkali–enriched diet blunted post-uninephrectomy hypertension and facilitated acid clearance by suppressing proximal Na+ transporters and increasing K+-alkali secretion. Furthermore, uninephrectomy-associated proteinuria could be attributed, at least in part, to elevated single-nephron GFR coupled with downregulation of megalin, which reduced fractional protein endocytosis and Vmax.

Podcast

This article contains a podcast at https://dts.podtrac.com/redirect.mp3/www.asn-online.org/media/podcast/JASN/2024_07_31_ASN0000000000000420.mp3

Risk of new onset hyperuricemia and chronic kidney disease after living kidney donation through propensity score matching analysis

Living kidney donors have been regarded as those people having earned the healthiest status level after having undergone scrutiny. Although one's post-donation GFR is expected to fall to 50% of their pre-donation value, it is well documented that there is a compensatory increase in GFR which subsequently reaches approximately 60-70% of the donor's pre-donation value. Data regarding gout/hyperuricemia in living kidney donors has remained scarce until now. This study involved kidney donors enrolled within the years 2000 to 2017, where those who were selected to be matched to those in group of case cohort by age, year of index date, gender and co-morbidity were considered as the control cohort. During the 17-year study period 2,716 participants were enrolled. Results revealed that kidney donors experienced a risk of new onset gout/ hyperuricemia (adjusted HR = 1.73; 95%CI = 1.27, 2.36), and new onset CKD (adjusted HR = 6.7; 95% CI = 4.4, 10.21) were found to be higher in kidney donors. Our findings suggest that people after kidney donation are significantly associated with a higher risk of new onset gout/hyperuricemia. Clinical professionals therefore need to be cautious of new onset gouy/hyperuricemia after donation surgery.

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.

Worsening of Diabetes Control Measures and Decreased Kidney Function in Pre-Diabetic Kidney Donors Compared to Non-Diabetic Donors Whose BMI Before Kidney Donation was Above 30

BACKGROUND

The incidence of end-stage renal disease has increased dramatically over the past two decades. Kidney transplantation is the best treatment option for individuals with end-stage renal disease, and living donor kidney transplantation has significant advantages over deceased donor kidney transplantation. Although there are criteria for assessing living kidney donors, different medical centers handle certain medical problems differently. The aim of this study is to investigate how kidney donation affects renal biochemical indicators, blood pressure measurements, and glucose control in healthy young female adults without diabetes compared to a pre-diabetic group.

METHODS

A prospective cohort study recruited 142 female kidney donors, who were divided into two cohorts based on their diabetic history (pre-diabetic and non-diabetic). The participants were monitored for seven years after kidney donation. Key clinical and biochemical markers were measured before and after donation.

RESULTS

The pre-diabetic group had higher mean values for blood pressure readings, body mass indices, Oral Glucose Tolerance Test, HbA1c (DCCT) (%), serum creatinine levels, proteinuria, and lower e-GFR compared to those in the non-diabetic group. All these findings were statistically significant.

CONCLUSIONS

Pre-diabetic donors are at an increased risk for many adverse clinical and biochemical outcomes, including hypertension, glucose tolerance, and worsening kidney function tests and should be advised that their condition may worsen over time and can result in end-organ complications. If the donors decide to proceed, they should be closely and frequently monitored during both the short- and long-term periods.

The psychology, legality, ethics and medical aspects of organ donation by minors

Any individual who has not attained the chronological age of legal majority as per national law is termed a minor. The concept of living donation (LD) has always been a subject of ethical debate and further compounding the controversy is the question of LD by minors. The decision for a minor to donate poses a special challenge as it involves a close family unit of parent-child relationship. Such an emotionally loaded situation wherein questions of attachment, perceived duties, moral obligation are likely to cloud a truly informed consent on the part of the minor to donation, who may find themselves in a vulnerable position. Furthermore, a minor's cognitive ability to comprehend the gravity of LD and when required defy parental coercion need to be elucidates before a minor is accepted for LD. Experts have set out stringent conditions which need to be met prior to the exceptional circumstance that a minor is considered for organ donation. Such donations should require parental permission, child's assent and the involvement of a paediatric-trained donor advocacy team. This article debates the question of minors acting as live donors from ethical, medical, psychosocial and legal viewpoints with an aim to present internationally defined circumstances when a minor may morally participate as a LD, thereby laying the foundation for future deliberations in this regard using traditional metrics to juxtapose divergent courses of action.

The Ultrasound Renal Stress Test for the Assessment of Functional Renal Reserve in Kidney Transplantation: A Pilot Study in Living Donors

In the evolving landscape of nephrology and kidney transplants, assessing renal functional reserve (RFR) in living kidney donors is essential for ensuring donor safety and successful transplantation. This study explores the use of the Intra-Parenchymal Renal Resistive Index Variation (IRRIV) test, a novel non-invasive method, to measure RFR in living donors. Our observational study included 11 participants undergoing living kidney donations, evaluated using the IRRIV-based Renal Stress Test (RST) before and 12 months post-nephrectomy. The study demonstrated significant changes in creatinine and eGFR CKD-EPI levels post-donation, with an average creatinine rise from 69 to 97 µmol/L and a reduction in eGFR from 104 to 66 mL/min/1.73 m2. These variations align with the expected halving of nephron mass post-nephrectomy and the consequent recruitment of RFR and hyperfiltration in the remaining nephrons. This pilot study suggests that the IRRIV-based RST is a practical, safe, and reproducible tool, potentially revolutionizing the assessment of RFR in living kidney donors, with implications for broader clinical practice in donor eligibility evaluation, even in borderline renal cases. Furthermore, it confirms the feasibility of RST in living kidney donors and allows us to assess the sample size in 48 donors for a future study.

"You don't know what you don't know": A qualitative study of informational needs of patients, family members, and living donors to inform transplant system metrics

INTRODUCTION

Informational needs and potential use of transplant metrics, especially among patients, remain understudied and a critical component of the transplant community's commitment to patient-centered care. We sought to understand the perspectives and needs of patients, family members/caregivers, living donors, and deceased donor family members.

METHODS

We examined decision-making experiences and perspectives on the needs of these stakeholder groups for data about the national transplant system among 58 participants of 14 focus groups and 6 interviews.

RESULTS

Three major themes emerged: 1) informational priorities and unmet needs (transplantation system processes, long-term outcomes data, prelisting data, patient-centered outcomes, and ability to compare centers and regions); 2) challenges obtaining relevant and trustworthy information (patient burden and effort, challenges with medical jargon, and difficulty finding trustworthy information); and 3) burden of facing the unknown (stress and anxiety leading to difficulty processing information, challenges facing the transplant journey when you "don't know what you don't know").

CONCLUSION

Patient, family member, and living donor participation in shared decision-making has been limited by inadequate access to patient-centered information. New metrics and patient-facing data presentations should address these content gaps using best practices to improve understanding and support shared decision-making.

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.

The Number and Size of Individual Kidney Medullary Pyramids is Associated with Clinical Characteristics, Kidney Biopsy Findings, and CKD Outcomes among Kidney Donors

SIGNIFICANCE STATEMENT

Segmentation of multiple structures in cross-sectional imaging is time-consuming and impractical to perform manually, especially if the end goal is clinical implementation. In this study, we developed, validated, and demonstrated the capability of a deep learning algorithm to segment individual medullary pyramids in a rapid, accurate, and reproducible manner. The results demonstrate that cortex volume, medullary volume, number of pyramids, and mean pyramid volume is associated with patient clinical characteristics and microstructural findings and provide insights into the mechanisms that may lead to CKD.

BACKGROUND

The kidney is a lobulated organ, but little is known regarding the clinical importance of the number and size of individual kidney lobes.

METHODS

After applying a previously validated algorithm to segment the cortex and medulla, a deep-learning algorithm was developed and validated to segment and count individual medullary pyramids on contrast-enhanced computed tomography images of living kidney donors before donation. The association of cortex volume, medullary volume, number of pyramids, and mean pyramid volume with concurrent clinical characteristics (kidney function and CKD risk factors), kidney biopsy morphology (nephron number, glomerular volume, and nephrosclerosis), and short- and long-term GFR <60 or <45 ml/min per 1.73 m 2 was assessed.

RESULTS

Among 2876 living kidney donors, 1132 had short-term follow-up at a median of 3.8 months and 638 had long-term follow-up at a median of 10.0 years. Larger cortex volume was associated with younger age, male sex, larger body size, higher GFR, albuminuria, more nephrons, larger glomeruli, less nephrosclerosis, and lower risk of low GFR at follow-up. Larger pyramids were associated with older age, female sex, larger body size, higher GFR, more nephrons, larger glomerular volume, more nephrosclerosis, and higher risk of low GFR at follow-up. More pyramids were associated with younger age, male sex, greater height, no hypertension, higher GFR, lower uric acid, more nephrons, less nephrosclerosis, and a lower risk of low GFR at follow-up.

CONCLUSIONS

Cortex volume and medullary pyramid volume and count reflect underlying variation in nephron number and nephron size as well as merging of pyramids because of age-related nephrosclerosis, with loss of detectable cortical columns separating pyramids.

Medical-ethical guidelines: Living donation of solid organs

No abstract available.