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.

National Attitudes Toward Living Kidney Donation in the United States: Results of a Public Opinion Survey

Rationale & Objective

Understanding national attitudes about living kidney donation will enable us to identify and address existing disincentives to living kidney donation. We performed a national survey to describe living kidney donation perceptions, perceived factors that affect the willingness to donate, and analyzed differences by demographic subgroups.

Study Design

The survey items captured living kidney donation awareness, living kidney donation knowledge, willingness to donate, and barriers and facilitators to living kidney donation.

Setting & Population

We surveyed 802 US adults (aged 25-65 years) in June 2021, randomly selected from an online platform with diverse representation.

Analytical Approach

We developed summed, scaled indices to assess the association between the living kidney donation knowledge (9 items) and the willingness to donate (8 items) to self-reported demographic characteristics and other variables of interest using analysis of variance. All other associations for categorical questions were calculated using Pearson's χ2 and Fisher exact tests. We inductively evaluated free-text responses to identify additional barriers and facilitators to living kidney donation.

Results

Most (86.6%) of the respondents reported that they might or would definitely consider donating a kidney while they were still living. Barriers to living kidney donation included concerns about the risk of the surgery, paying for medical expenses, and potential health effects. Facilitators to living kidney donation included having information on the donation surgery's safety, knowing that the donor would not have to pay for medical expenses related to the donation, and hearing living kidney donation success stories. Awareness of the ability to participate in kidney-paired donation was associated with a higher willingness to donate.

Limitations

Potential for selection bias resulting from the use of survey panels and varied incentive amounts, and measurement error related to respondents' attention level.

Conclusions

Most people would consider becoming a living kidney donor. Increased rates of living kidney donation may be possible with investment in culturally competent educational interventions that address risks associated with donating, policies that reduce financial disincentives, and communication campaigns that raise awareness of kidney-paired donation and living kidney donation.

'It is a life changing experience': The experiences of living kidney donors who live in rural Australia

INTRODUCTION

A growing body of research has examined the physical, psychological, social and financial impacts of living kidney donation. However, little is known about the unique experiences or additional burdens faced by living donors from regional or remote locations.

OBJECTIVE

To explore the experiences of living kidney donors who live outside metropolitan centres and to determine how support services could be orientated to better meet their unique needs.

DESIGN/SETTING/PARTICIPANTS

Seventeen living kidney donors participated in semistructured telephone interviews. Qualitative data were analysed using thematic analysis.

FINDINGS

Eight themes were identified: (1) donor's emotional well-being is influenced by the recipient's outcome, (2) varied levels of access to medical support and other important services in rural areas, (3) travel takes a toll on time, finances and well-being, (4) varied level of financial impact, (5) medical, emotional and social challenges, (6) both lay and health professional support is valued, (7) varied levels of knowledge and experiences accessing information and (8) a worthwhile experience overall.

CONCLUSION

Despite many challenges, and travel adding to the complexity, rural living kidney donors generally consider it to be a worthwhile experience. The provision of additional emotional, practical and educational support would be welcomed by this group.

Relationship between cortical and medullary thickness and glomerular filtration rate among living kidney donors

The relationship between the kidney cortex and medulla is not well understood in healthy populations. This study characterised the relationship between cortical/medullary thickness and measured glomerular filtration rate (GFR) in 390 living kidney donors. A positive relationship was observed between medullary, but not cortical, thickness and GFR. We propose that this reflects a correlation between juxtamedullary nephron number and GFR.

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.

Controversies in Living Kidney Donation

The most precious gift that can be given is, arguably, a living organ to a person in need of replacement because of failure of that organ. Kidney transplantation remains the best modality of renal replacement therapy and there is an ever-increasing demand for organ donation. The inability of cadaveric organ donation to meet the needs of the increasing numbers of patients on global waiting lists highlights the important needs for alternate sources for kidneys such as those from living kidney donation. However, living donor kidney transplantation has been a focus of intense debate, with ethical concerns and controversies emanating from operating on an individual who does not need, and is put at a small but quantifiable risk from, the surgical intervention. Furthermore, health care systems across the world also are funded with different levels of national and individual affordability, leading to health inequalities for the sick and risks of exploitation for the poor, especially through commercialization of transplantation. This article highlights some of these contemporary ethical concerns and controversies in living organ donation.

Vignette-Based Reflections to Inform Genetic Testing Policies in Living Kidney Donors

Family history of kidney disease increases risk of end-stage kidney disease (ESKD) in donors. Pre-donation genetic testing is recommended in evaluation guidelines and regulatory policy. Collaborating across several institutions, we describe cases to illustrate the utility as well as practical issues in incorporating genetic testing in transplant protocols. Case 1 is from 2009, before pervasive genetic testing. A healthy 27-year-old Caucasian male had an uneventful donor evaluation for his mother, who had early onset ESKD of unclear cause. He participated in paired-exchange kidney donation, but developed progressive kidney disease and gout over the next 10 years. A uromodulin gene mutation (NM_003361.3(UMOD):c.377 G>A p.C126Y) was detected and kidney biopsy showed tubulointerstitial kidney disease. The patient subsequently required kidney transplantation himself. Case 2 was a 36-year-old African American female who had an uneventful kidney donor evaluation. She underwent gene panel-based testing to rule out ApolipoproteinL1 risk variants, for which was negative. Incidentally, a sickle-cell trait (NM_000518.5(HBB):c.20A>T p.Glu7Val) was noted, and she was declined for kidney donation. This led to significant patient anguish. Case 3 was a 26-year-old Caucasian female who underwent panel-based testing because the potential recipient, her cousin, carried a variant of uncertain significance in the hepatocyte nuclear factor-1-β (HNF1B) gene. While the potential donor did not harbor this variant, she was found to have a likely pathogenic variant in complement factor I (NM_000204.4(CFI):c.1311dup:p.Asp438Argfs*8), precluding kidney donation. Our cases emphasize that while genetic testing can be invaluable in donor evaluation, transplant centers should utilize detailed informed consent, develop care pathways for secondary genetic findings, and share experience to develop best practices around genetic testing in donors.

Evaluating a Living Donor With Rheumatoid Arthritis for a Recipient With End-Stage Renal Disease From Antineutrophil Cytoplasmic Antibodies Associated Vasculitis

A 60-year-old Caucasian female with sero-positive rheumatoid arthritis (RA) was evaluated as a potential kidney donor for her brother-in-law with end-stage kidney disease (ESKD) secondary to c-antineutrophil cytoplasmic antibody (c-ANCA) associated vasculitis (AAV) and membranous nephropathy (MN). With little to no data supporting or contradicting this unique scenario, in addition to the varying viewpoints expressed by the different specialists, our multidisciplinary transplant committee encountered a difficult decision of whether to approve a candidate with RA for a living kidney donation or not. As a result, we carried out a careful literature review addressing aspects of recipients' outcomes following kidney transplants from a living donor with RA, especially when the recipient has AAV, living donor's short- and long-term outcomes post kidney donation, renal disease in AAV and RA, and maintenance of disease remission.

The Evaluation of Kidney Function in Living Kidney Donor Candidates

Living kidney donors incur a small increased risk of ESKD, of which predonation GFR is an important determinant. As a result, kidney function assessment is central to the donor candidate evaluation and selection process. This article reviews the different methods of GFR assessment, including eGFR, creatinine clearance, and measured GFR, and the current guidelines on GFR thresholds for donor acceptance. eGFR obtained using the 2009 CKD Epidemiology Collaboration equation that, although the best of estimating estimations, tends to underestimate levels and has limited accuracy, especially near-normal GFR values. In the United States, the Organ Procurement and Transplantation Network policy on living donation mandates either measured GFR or creatinine clearance as part of the evaluation. Measured GFR is considered the gold standard, although there is some variation in performance characteristics, depending on the marker and technique used. Major limitations of creatinine clearance are dependency on accuracy of timed collection, and overestimation as a result of distal tubular creatinine secretion. GFR declines with healthy aging, and most international guidelines recommend use of age-adapted selection criteria. The 2017 Kidney Disease: Improving Global Outcomes Guideline for the Evaluation and Care of Living Kidney Donors diverges from other guidelines and recommends using absolute cutoff of <60 ml/min per 1.73m² for exclusion and ≥90 ml/min per 1.73m² for acceptance, and determination of candidacy with intermediate GFR on the basis of long-term ESKD risk. However, several concerns exist for this strategy, including inappropriate acceptance of younger candidates due to underestimation of risk, and exclusion of older candidates whose kidney function is in fact appropriate for age. The role of cystatin C and other newer biomarkers, and data on the effect of predonation GFR on not just ESKD risk, but also advanced CKD risk and cardiovascular outcomes are needed.

Podometrics in Japanese Living Donor Kidneys: Associations with Nephron Number, Age, and Hypertension

BACKGROUND

Podocyte depletion, low nephron number, aging, and hypertension are associated with glomerulosclerosis and CKD. However, the relationship between podometrics and nephron number has not previously been examined.

METHODS

To investigate podometrics and nephron number in healthy Japanese individuals, a population characterized by a relatively low nephron number, we immunostained single paraffin sections from 30 Japanese living-kidney donors (median age, 57 years) with podocyte-specific markers and analyzed images obtained with confocal microscopy. We used model-based stereology to estimate podometrics, and a combined enhanced-computed tomography/biopsy-specimen stereology method to estimate nephron number.

RESULTS

The median number of nonsclerotic nephrons per kidney was 659,000 (interquartile range [IQR], 564,000-825,000). The median podocyte number and podocyte density were 518 (IQR, 428-601) per tuft and 219 (IQR, 180-253) per 10⁶μm³, respectively; these values are similar to those previously reported for other races. Total podocyte number per kidney (obtained by multiplying the individual number of nonsclerotic glomeruli by podocyte number per glomerulus) was 376 million (IQR, 259-449 million) and ranged 7.4-fold between donors. On average, these healthy kidneys lost 5.63 million podocytes per kidney per year, with most of this loss associated with glomerular loss resulting from global glomerulosclerosis, rather than podocyte loss from healthy glomeruli. Hypertension was associated with lower podocyte density and larger podocyte volume, independent of age.

CONCLUSIONS

Estimation of the number of nephrons, podocytes, and other podometric parameters in individual kidneys provides new insights into the relationships between these parameters, age, and hypertension in the kidney. This approach might be of considerable value in evaluating the kidney in health and disease.

Education Priorities and What Matters to Those Considering Living Kidney Donation

INTRODUCTION

Although informed consent content elements are prescribed in detailed regulatory guidance, many live kidney donors describe feeling underprepared and under informed. The goal of this pilot study was to explore the educational components needed to support an informed decision-making process for living kidney donors.

METHODS/APPROACH

A qualitative description design was conducted with thematic analysis of 5 focus groups with 2 cohorts: living kidney donor candidates (n = 11) and living kidney donors (n = 8).

FINDINGS

The educational components needed to engage in an informed decision-making process were: 1) contingent upon, and motivated by, personal circumstances; 2) supported through explanation of risks and benefits; 3) enhanced by understanding the overall donation experience; and 4) personalized by talking to another donor.

DISCUSSION

Tailoring education to meet the needs for fully informed decision-making is essential. Current education requirements, as defined by regulatory bodies, remain challenging to transplant teams attempting to ensure fully informed consent of living kidney donor candidates. Information on the emotional, financial, and overall life impact is needed, along with acknowledgement of relational ties driving donor motivations and the hoped-for recipient outcomes. Discussion of care practices, and access to peer mentoring may further strengthen the informed decision-making process.

Kidney exchange strategies: new aspects and applications with a focus on deceased donor-initiated chains

Kidney paired donation (KPD) is a valuable way to overcome immunological incompatibility in the context of living donation, and several strategies have been implemented to boost its development. In this article, we reviewed the current state of the art in this field, with a particular focus on advanced KPD strategies, including the most recent idea of initiating living donor (LD) transplantation chains with a deceased donor (DD) kidney, first applied successfully in 2018. Since then, Italy has been running a national programme in which a chain-initiating kidney is selected from a DD pool and allocated to a recipient with an incompatible LD, and the LD's kidney is transplanted into a patient on the waiting list (WL). At this stage, since the ethical and logistic issues have been managed appropriately, KPD starting with a DD has proved to be a feasible strategy. It enables transplants in recipients of incompatible pairs without the need for desensitizing and also benefits patients on the WL who are allocated chain-ending kidneys from LDs (prioritizing sensitized patients and those on the WL for longer).

Prescription patterns of opioids and non-steroidal anti-inflammatory drugs in the first year after living kidney donation: An analysis of U.S. Registry and Pharmacy fill records

We examined a novel database linking national donor registry identifiers to records from a US pharmaceutical claims warehouse (2007-2015) to describe opioid and NSAID prescription patterns among LKDs during the first year postdonation, divided into three periods: 0-14 days, 15-182 days, and 183-365 days. Associations of opioid and NSAID prescription fills with baseline factors were examined by logistic regression (adjusted odds ratio, LCL aORUCL ). Among 23,565 donors, opioid prescriptions were highest during days 0-14 (36.6%), but 12.6% of donors filled opioids during days 183-365. NSAID prescriptions rose from 0.5% during days 0-14 to 3.3% during days 183-365. Women filled opioids more commonly than men, and black donors filled both opioids and NSAIDs more commonly than white donors. After covariate adjustment, significant correlates of opioid prescription fills during days 183-365 included obesity (aOR,1.24 1.381.53 ), less than college education (aOR,1.19 1.311.43 ), smoking (aOR,1.33 1.451.58 ), and nephrectomy complications (aOR,1.11 1.291.49 ). NSAID prescription fills in year 1 were not associated with differences in estimated glomerular filtration rate, incidence of proteinuria or new-onset hypertension at the first and second year postdonation. Prescription fills for opioids and NSAIDs for LKDs varied with demographic and clinic traits. Future work should examine longer-term outcome implications to help inform safe analgesic regimen choices after donation.

Use of Dietary Supplements in Living Kidney Donors: A Critical Review

Dietary supplement use is high among US adults, with the intention by users to promote overall health and wellness. Kidney donors, who are selected based on their overall good health and wellness, can have high utilization rates of dietary supplements. We provide a framework for the evaluation of living kidney donors and use of dietary supplements. In this review, dietary supplements will include any orally administered dietary or complementary nutritional products, but excluding micronutrients (vitamins and minerals), food, and cannabis. Use of dietary supplements can influence metabolic parameters that mask future risk for chronic illness such as diabetes and hypertension. Dietary supplements can also alter bleeding risk, anesthesia and analgesic efficacy, and safety in a perioperative period. Finally, postdonation monitoring of kidney function and risk for supplement-related nephrotoxicity should be part of a kidney donor educational process. For practitioners evaluating a potential kidney donor, we provide a list of the most commonly used herbal supplements and the effects on evaluation in a predonation, perioperative donation, and postoperative donation phase. Finally, we provide recommendations for best practices for integration into a comprehensive care plan for kidney donors during all stages of evaluation. We recommend avoidance of dietary supplements in a kidney donor population, although there is a paucity of data that identifies true harm. Rather, associations, known mechanisms of action, and common sense suggest that we avoid use in this population.

Canadian Society of Transplantation and Canadian Society of Nephrology Commentary on the 2017 KDIGO Clinical Practice Guideline on the Evaluation and Care of Living Kidney Donors

Purpose of review:

To review an international guideline on the evaluation and care of living kidney donors and provide a commentary on the applicability of the recommendations to the Canadian donor population.

Sources of information:

We reviewed the 2017 Kidney Disease: Improving Global Outcomes (KDIGO) Clinical Practice Guideline on the Evaluation and Care of Living Kidney Donors and compared this guideline to the Canadian 2014 Kidney Paired Donation (KPD) Protocol for Participating Donors.

Methods:

A working group was formed consisting of members from the Canadian Society of Transplantation and the Canadian Society of Nephrology. Members were selected to have representation from across Canada and in various subspecialties related to living kidney donation, including nephrology, surgery, transplantation, pediatrics, and ethics.

Key findings:

Many of the KDIGO Guideline recommendations align with the KPD Protocol recommendations. Canadian researchers have contributed to much of the evidence on donor evaluation and outcomes used to support the KDIGO Guideline recommendations.

Limitations:

Certain outcomes and risk assessment tools have yet to be validated in the Canadian donor population.

Implications:

Living kidney donors should be counseled on the risks of postdonation outcomes given recent evidence, understanding the limitations of the literature with respect to its generalizability to the Canadian donor population.

Long-term Mortality Risks Among Living Kidney Donors in Korea

RATIONALE & OBJECTIVE

Living kidney donors may have a higher risk for death and kidney failure. This study aimed to investigate the long-term mortality experience of living kidney donors compared with members of the general public in Korea who underwent voluntary health examinations.

STUDY DESIGN

Cohort study.

SETTING & PARTICIPANTS

We first calculated standardized mortality ratios for 1,292 Korean living kidney donors who underwent donor nephrectomy between 1982 and 2016 and 72,286 individuals who underwent voluntary health examinations between 1995 and 2016. Next we compared survival between the 1,292 living kidney donors and a subgroup of the health examination population (n=33,805) who had no evident contraindications to living kidney donation at the time of their examinations. Last, a matched comparator group was created from the health examination population without apparent contraindication to donation by matching 4,387 of them to donors (n=1,237) on age, sex, body mass index, estimated glomerular filtration rate, urine dipstick albumin excretion, previously diagnosed hypertension and diabetes, and era.

EXPOSURES

Donor nephrectomy.

OUTCOMES

All-cause mortality and other clinical outcomes after kidney donation.

ANALYTICAL APPROACH

First, standardized mortality ratios were calculated separately for living kidney donors and the health examination population standardized to the general population. Second, we used Cox regression analysis to compare mortality between living kidney donors versus the subgroup of the health examination population without evident donation contraindications. Third, we used Cox regression analysis to compare mortality between living kidney donors and matched comparators from the health examination population without apparent contraindication to donation.

RESULTS

The living kidney donors and health examination population had excellent survival rates compared with the general population. 52 (4.0%) of 1,292 kidney donors died during a mean follow-up of 12.3±8.1 years and 1,072 (3.2%) of 33,805 in the health examiner subgroup without donation contraindications died during a mean follow-up of 11.4±6.1 years. Donor nephrectomy did not elevate the hazard for mortality after multivariable adjustment in kidney donors and the 33,805 comparators (adjusted HR, 1.01; 95% CI, 0.71-1.44; P=0.9). Moreover, living donors showed a similar mortality rate compared with the group of matched healthy comparators.

LIMITATIONS

Donors from a single transplantation center. Residual confounding owing to the observational study design.

CONCLUSIONS

Kidney donors experienced long-term rates of death comparable to nondonor comparators with similar health status.

Why do not all living kidney donor candidates proceed to donation?

There are national and international guidelines for donor workup and acceptance criteria of potential living kidney donor candidates (LKDC), but there is significant variation in clinical practice. We examined our local practice in assessing potential LKDC against current guidelines; nearly all of our accepted donors met these guidelines. LKDC who did not proceed to donation had an identified health issue (60%), the presence of risk factors for long-term end-stage kidney disease (17%), social (13%) or immunological reasons (7%).

In sickness and in health: Living HIV positive kidney donation from a wife to her husband, with 7 years' post-transplant follow-up

Human immunodeficiency virus (HIV) infection was traditionally considered an absolute contraindication for kidney transplantation. After the introduction of ART, several studies have demonstrated comparable patient and graft outcomes between HIV-negative and HIV-positive kidney recipients. The US Congress passed the HIV Organ Policy Equity (HOPE) Act in 2013, which permits research in the area of HIV-positive to HIV-positive transplantation. HIV-infected living donation is also permitted under the HOPE Act. However, there is a concern regarding the safety of kidney donation in an HIV-infected person, given the risk of renal disease associated with HIV infection. We report here the case of successful kidney transplantation from HIV-positive living donor to HIV-positive recipient performed in our center on July 2012. To the best of our knowledge, this is the earliest case done in this medical context to be reported in the literature, therefore, potentially carrying several important messages to the transplantation community. In the present case, the living-donor kidney transplant was performed between a married couple infected with same strain of HIV-1, both on effective ART with efficiently suppressed viral replication and satisfactory pre-transplantation immune status.

Can Split Renal Volume Assessment by Computed Tomography Replace Nuclear Split Renal Function in Living Kidney Donor Evaluations? A Systematic Review and Meta-Analysis

Background:

As part of their living kidney donor assessment, all living donor candidates complete a computed tomography (CT) angiogram, but some also receive a nuclear renogram for split renal function (SRF%).

Objective:

We considered whether split renal volume (SRV%) assessed by CT can predict SRF%.

Design:

Systematic review and meta-analysis.

Setting:

Living donor candidates undergoing evaluation as potential living kidney donors.

Patients:

Living donor candidates who received both a nuclear renogram for split function and CT for SRV as part of their living donor work-up.

Measurements:

Split renal volume from CT scans and SRF from nuclear renography.

Methods:

We performed a systematic review and meta-analysis of the literature, abstracting data and digitizing plots where possible. We searched Medline, EMBASE, and the Cochrane Library. We added data from donor candidates assessed in London, Ontario from 2013 to 2016. We used fixed and random-effects models to pool Fisher’s z-transformed Pearson’s correlation coefficient (r). We conducted random-effects meta-regression on digitized and aggregate data. Studies were restricted to living kidney donors or living donor candidates.

Results:

After pooling 19 studies (n = 1479), we obtained a pooled correlation of r = 0.74 (95% confidence interval [CI] = 0.61-0.82). By linear regression using individual-level data, we observed a 0.76% (95% CI = 0.71-0.81) increase in SRF% for every 1% increase in SRV%. Split renal volume had a specificity of 88% for discriminating SRF at a threshold that could influence the decision of which kidney is to be removed (between-kidney difference ≥10%). Predonation SRV and SRF both moderately predicted kidney function 6 to 12 months after donation: r = 0.75 for SRV and r = 0.73 for SRF; Δr = 0.05 (–0.02, 0.13).

Limitations:

Most studies were retrospective and measured SRV and SRF only on selected living donor candidates. Efficiency gains in removing the SRF from the evaluation will depend on the transplant program.

Conclusion:

Split renal volume has the potential to replace SRF for some candidates. However, it is uncertain whether it can do so reliably and routinely across different transplant centers. The impact on clinical decision-making needs to be assessed in well-designed prospective studies.

Trial registration:

The digitized data are registered with Mendeley Data (doi10.17632/dyn2bfgxxj.2).

Perioperative Complications During Living Donor Nephrectomy: Results From a Multicenter Cohort Study

BACKGROUND

While living kidney donation is considered safe in healthy individuals, perioperative complications can occur due to several factors.

OBJECTIVE

We explored associations between the incidence of perioperative complications and donor characteristics, surgical technique, and surgeon's experience in a large contemporary cohort of living kidney donors.

DESIGN

Living kidney donors enrolled prospectively in a multicenter cohort study with some data collected retrospectively after enrollment was complete (eg, surgeon characteristics).

SETTING

Living kidney donor centers in Canada (n = 12) and Australia (n = 5).

PATIENTS

Living kidney donors who donated between 2004 and 2014 and the surgeons who performed the living kidney donor nephrectomies.

MEASUREMENTS

Operative and hospital discharge medical notes were collected prospectively, with data on perioperative (intraoperative and postoperative) information abstracted from notes after enrollment was complete. Complications were graded using the Clavien-Dindo system and further classified into minor and major. In 2016, surgeons who performed the nephrectomies were invited to fill an online survey on their training and experience.

METHODS

Multivariable logistic regression models with generalized estimating equations were used to compare perioperative complication rates between different groups of donors. The effect of surgeon characteristics on the complication rate was explored using a similar approach. Poisson regression was used to test rates of overall perioperative complications between high- and low-volume centers.

RESULTS

Of the 1421 living kidney donor candidates, 1042 individuals proceeded with donation, where 134 (13% [95% confidence interval (CI): 11%-15%]) experienced 142 perioperative complications (55 intraoperative; 87 postoperative). The most common intraoperative complication was organ injury and the most common postoperative complication was ileus. No donors died in the perioperative period. Most complications were minor (90% of 142 complications [95% CI: 86%-96%]); however, 12 donors (1% of 1042 [95% CI: 1%-2%]) experienced a major complication. No statistically significant differences were observed between donor groups and the rate of complications. A total of 43 of 48 eligible surgeons (90%) completed the online survey. Perioperative complication rates did not vary significantly by surgeon characteristics or by high- versus low-volume centers.

LIMITATIONS

Operative and discharge reporting is not standardized and varies among surgeons. It is possible that some complications were missed. The online survey for surgeons was completed retrospectively, was based on self-report, and has not been validated. We had adequate statistical power only to detect large effects for factors associated with a higher risk of perioperative complications.

CONCLUSIONS

This study confirms the safety of living kidney donation as evidenced by the low rate of major perioperative complications. We did not identify any donor or surgeon characteristics associated with a higher risk of perioperative complications.

TRIAL REGISTRATIONS

NCT00319579: A Prospective Study of Living Kidney Donation (https://clinicaltrials.gov/ct2/show/NCT00319579)NCT00936078: Living Kidney Donor Study (https://clinicaltrials.gov/ct2/show/NCT00936078).

Assessment of renal function in living kidney donors before and after nephrectomy: A Japanese prospective, observational cohort study

OBJECTIVE

To investigate the utility of estimated glomerular filtration rate for assessing kidney function in living kidney donors before and after nephrectomy.

METHODS

A total of 101 donors underwent inulin clearance measurements before and 1 year after nephrectomy. The mean of three inulin clearance values was used as the measured glomerular filtration rate. Estimated glomerular filtration rate based on serum creatinine and cystatin C levels was calculated using the Japanese estimated glomerular filtration rate equation, Chronic Kidney Disease Epidemiology Collaboration formula and new full age spectrum equation. Age-adjusted chronic kidney disease was defined as glomerular filtration rate <75 mL/min/1.73m² for donors aged <40 years, <60 mL/min/1.73m² for donors aged 40-65 years and <45 mL/min/1.73m² for donors aged >65 years.

RESULTS

The postoperative measured glomerular filtration rate <60 mL/min/1.73m² and age-adjusted chronic kidney disease rate were 36.0% and 27.0%, respectively. In younger donors (aged <50 years), postoperative measured glomerular filtration rate <60 mL/min/1.73m² and age-adjusted chronic kidney disease rates were 5.3% and 26.3%, respectively. In older donors (aged >70 years), postoperative measured glomerular filtration rate <60 mL/min/1.73m² and age-adjusted chronic kidney disease rates were 75.0% and 33.3%, respectively. Donor age and measured glomerular filtration rate were significant predictors of postoperative measured glomerular filtration rate. The Japanese estimated glomerular filtration rate equation based on creatinine and cystatin C showed the strongest correlation with measured glomerular filtration rate. However, the Japanese estimated glomerular filtration rate equation based on creatinine overestimated the prevalence of measured glomerular filtration rate <60 mL/min/1.73m² , whereas the Japanese estimated glomerular filtration rate based on cystatin C underestimated it.

CONCLUSIONS

Aged donors might have an increased risk of lower glomerular filtration rate after donor nephrectomy; post-surgery, long-term monitoring of renal function is recommended. Measurement of glomerular filtration rate should be carried out for donors, especially pre-surgery. A more precise glomerular filtration rate equation is required in the future.

Risk of subsequent health disorders among living kidney donors

Few studies have investigated the risk of physiological sequelae in living kidney donors (KDs). We conducted a population-based cohort study using the National Health Insurance Research Database of Taiwan, which covers more than 99% of citizens.We comprehensively investigated the risk of medical disorders after kidney donation in living KDs using a maximum follow-up of 13 years. From January 1997 to December 2010, 1081 living KDs and 1082 age- and sex-matched non-KDs were eligible. Primary outcomes comprised end-stage renal disease, chronic kidney disease, stroke, cancer, acute myocardial infarction, acute renal failure (ARF), and diabetes.The adjusted hazard ratios (HRs) for developing ARF, diabetes, hyperlipidemia, hypertension, cancer, end-stage renal disease, acute myocardial infarction, and stroke were similar between the KD and non-KD cohorts (P > .05). Although differences in the adjusted HRs of ARF were nonsignificant, the cumulative incidence rate of ARF 13 years after donation was 7.48 per 1000 person-years in the KD cohort compared with 3.46 in the matched non-KD cohort. The incidence rate ratio for ARF between donors and nondonors significantly increased to 2.16 (95% confidence interval, 1.61-2.71).Living KDs experienced no significant health disorders following kidney donation but should be alert to the higher incidence rate of ARF.

Assessing the Attitudes and Perceptions Regarding the Use of Mobile Health Technologies for Living Kidney Donor Follow-Up: Survey Study

BACKGROUND

In 2013, the Organ Procurement and Transplantation Network began requiring transplant centers in the United States to collect and report postdonation living kidney donor follow-up data at 6 months, 1 year, and 2 years. Despite this requirement, <50% of transplant centers have been able to collect and report the required data. Previous work identified a number of barriers to living kidney donor follow-up, including logistical and administrative barriers for transplant centers and cost and functional barriers for donors. Novel smartphone-based mobile health (mHealth) technologies might reduce the burden of living kidney donor follow-up for centers and donors. However, the attitudes and perceptions toward the incorporation of mHealth into postdonation care among living kidney donors are unknown. Understanding donor attitudes and perceptions will be vital to the creation of a patient-oriented mHealth system to improve living donor follow-up in the United States.

OBJECTIVE

The goal of this study was to assess living kidney donor attitudes and perceptions associated with the use of mHealth for follow-up.

METHODS

We developed and administered a cross-sectional 14-question survey to 100 living kidney donors at our transplant center. All participants were part of an ongoing longitudinal study of long-term outcomes in living kidney donors. The survey included questions on smartphone use, current health maintenance behaviors, accessibility to health information, and attitudes toward using mHealth for living kidney donor follow-up.

RESULTS

Of the 100 participants surveyed, 94 owned a smartphone (35 Android, 58 iPhone, 1 Blackberry), 37 had accessed their electronic medical record on their smartphone, and 38 had tracked their exercise and physical activity on their smartphone. While 77% (72/93) of participants who owned a smartphone and had asked a medical question in the last year placed the most trust with their doctors, nurses, or other health care professionals regarding answering a health-related question, 52% (48/93) most often accessed health information elsewhere. Overall, 79% (74/94) of smartphone-owning participants perceived accessing living kidney donor information and resources on their smartphone as useful. Additionally, 80% (75/94) perceived completing some living kidney donor follow-up via mHealth as useful. There were no significant differences in median age (60 vs 59 years; P=.65), median years since donation (10 vs 12 years; P=.45), gender (36/75, 36%, vs 37/75, 37%, male; P=.57), or race (70/75, 93%, vs 18/19, 95%, white; P=.34) between those who perceived mHealth as useful for living kidney donor follow-up and those who did not, respectively.

CONCLUSIONS

Overall, smartphone ownership was high (94/100, 94.0%), and 79% (74/94) of surveyed smartphone-owning donors felt that it would be useful to complete their required follow-up with an mHealth tool, with no significant differences by age, sex, or race. These results suggest that patients would benefit from an mHealth tool to perform living donor follow-up.

Overweight young female kidney donors have low renal functional reserve postdonation

Maintenance of adequate renal function after living kidney donation is important for donor outcome. Overweight donors, in particular, may have an increased risk for end-stage kidney disease (ESKD), and young female donors have an increased preeclampsia risk. Both of these risks may be associated with low postdonation renal functional reserve (RFR). Because we previously found that higher body mass index (BMI) was associated with lower postdonation RFR, we now studied the relationship between BMI and RFR in young female donors. RFR, the rise in glomerular filtration rate (GFR) (¹²⁵I-iothalamate clearance) during dopamine, was measured in female donors (<45 yr) before and after kidney donation. Donors who are overweight (BMI >25) and nonoverweight donors were compared by Student's t-test; the association was subsequently explored with regression analysis. We included 105 female donors [age 41 (36-44) median(IQR)] with a BMI of 25 (22-27) kg/m². Predonation GFR was 118 (17) ml/min [mean(SD)] rising to 128 (19) ml/min during dopamine; mean RFR was 10 (10) ml/min. Postdonation GFR was 76 (13) ml/min, rising to 80 (12); RFR was 4 (6) ml/min ( P < 0.001 vs. predonation). In overweight donors, RFR was fully lost after donation (1 ml/min vs. 10 ml/min predonation, P < 0.001), and BMI was inversely associated with RFR after donation, independent of confounders (standardized β 0.37, P = 0.02). Reduced RFR might associate with the risk of preeclampsia and ESKD in kidney donors. Prospective studies should explore whether RFR is related to preeclampsia and whether BMI reduction before conception is of benefit to overweight female kidney donors during and after pregnancy.

Effect of unilateral nephrectomy on urinary angiotensinogen levels in living kidney donors: 1 year follow-up study

Background:

Urinary angiotensinogen (uAGT) has recently been proposed as a marker of kidney injury and activated intrarenal renin–angiotensin system. We investigated the effects of living donor nephrectomy on uAGT levels, blood pressure, estimated glomerular filtration rate, proteinuria and compensatory hypertrophy in the remaining kidney of living kidney donors.

Methods:

Twenty living kidney donors were included in the study and followed for 1 year. uAGT levels were measured with enzyme-linked immunosorbent assay preoperatively and postoperatively at the 15th day, 1, 6 and 12 months.

Results:

Four donors were excluded from the study due to lack of data. The mean baseline estimated glomerular filtration rate was 98 ± 15 ml/min/1.73 m². Serum creatinine, uAGT/creatinine, uAGT/protein levels were higher and estimated glomerular filtration rate was lower than baseline values at all time periods. Urinary protein/creatinine levels increased after donor nephrectomy, but after 6 months they returned to baseline values. Renal volume increased after nephrectomy, but these changes did not show any correlation with uAGT/creatinine, uAGT/protein, estimated glomerular filtration rate or systolic/diastolic blood pressures. uAGT/creatinine at 6 months and urinary protein/creatinine ratio at 12 months showed a positive correlation (P=0.008, r=0.639).

Conclusion:

After donor nephrectomy, increasing uAGT levels can be the result of activation of the intrarenal renin–angiotensin system affecting the compensatory changes in the remaining kidney. The long-term effects of increased uAGT levels on the remaining kidney should be examined more closely in future studies.

Electronic messaging and communication with living kidney donors

New regulations require living kidney donor (LKD) follow-up for 2 years, but donor retention remains poor. Electronic communication (eg, text messaging and e-mail) might improve donor retention. To explore the possible impact of electronic communication, we recruited LKDs to participate in an exploratory study of communication via telephone, e-mail, or text messaging postdonation; communication through this study was purely optional and did not replace standard follow-up. Of 69 LKDs recruited, 3% requested telephone call, 52% e-mail, and 45% text messaging. Telephone response rate was 0%; these LKDs were subsequently excluded from analysis. Overall response rates with e-mail or text messaging at 1 week, 1 month, 6 months, 1 year, and 2 years were 94%, 87%, 81%, 72%, and 72%. Lower response rates were seen in African Americans, even after adjusting for age, sex, and contact method (incidence rate ratio (IRR) nonresponse _2.07 5.81_16.36 , P = .001). Text messaging had higher response rates than e-mail (IRR nonresponse _0.11 0.28_0.71 , P = .007). Rates of nonresponse were similar by sex (IRR 0.68, P = .4) and age (IRR 1.00, P > .9). In summary, LKDs strongly preferred electronic messaging over telephone and were highly responsive 2 years postdonation, even in this nonrequired, nonincentivized exploratory research study. These electronic communication tools can be automated and may improve regulatory compliance and postdonation care.

Follow-up rates of living kidney donor in Japan: A single center study

Long-term follow-up of kidney donors is needed not only for the individual donor's benefit but also to establish analyzable databases to improve the selection criteria for future donors. We collected data including the date of transplantation, the date of the last follow-up, donor's age, sex, their relationship to the recipient, renal function, proteinuria, and the prevalence of hypertension. Of 124 donors, 52 donors were not being followed up. The mean duration of follow-up was 4.3 ± 3.6 years. Follow-up rates were 83.9%, 74.6%, and 59.2% at 1 year, 2 years, and 5 years postdonation, respectively. Of those not being followed up, 75% dropped out. Follow-up rates did not differ between parent and spouse donors 5 years (57.1% vs. 71.4%; P = 0.4) postdonation. Similarly, follow-up rates at 5 years did not differ between donors aged 60 years or older and those younger than 60 (57.5% vs. 61.3%; P = 0.6). Of 72 donors being followed up, 75.0% had estimated glomerular filtration rate of <60 mL/min/1.73 m², 8.3% had proteinuria, and 41.7% had hypertension requiring medication. There is a limitation to the endeavor of each transplant center to follow-up all their donors. Long-term donor follow-up in Japan requires a national registration system and mandates transplant center participation.

A meta-analysis of renal outcomes in living kidney donors

Given the increased burden of end-stage renal disease (ESRD), renal outcomes of kidney donation by living donors are of particular interest. PubMed, ProQuest, MEDLINE, EMBASE, Chinese national knowledge infrastructure, and Wanfang databases were searched for clinical outcomes of living kidney donors (LKDs) including renal death, ESRD, proteinuria/albuminuria, and renal function after donation. We included 62 studies from 19 countries involving 114,783 kidney donors and nondonors to evaluate the renal consequences less than 6 months, 6 months to 5 years, 5 to 10 years, and 10 years onward after donation. The pooled data showed that uninephrectomy significantly decreased glomerular filtration rate and creatinine clearance rate in parallel with increased serum creatinine concentration (all P < 0.05). The drastic changes in renal function occurred within 6 months rather than 5 to 10 years after donation. Ten years and onward, rate of proteinuria/albuminuria increased gradually: microalbuminuria from 5.3% to 20.9%, proteinuria from 4.7% to 18.9%, and overt proteinuria from 2.4% to 5.7% (all P < 0.05). Prevalence of ESRD was 1.1%. All-cause mortality was 3.8% and all the renal deaths on average occurred 10 years postnephrectomy. LKDs might have aggravated glomerular filtration and creatinine clearance within 6 months after donation. Five years and onward, albuminuria, proteinuria, ESRD, and death might be the major concerns of LKDs. Long-term studies may clarify the survival time after donation.

Detection and Clinical Patterns of Nephron Hypertrophy and Nephrosclerosis Among Apparently Healthy Adults

BACKGROUND

Even among ostensibly healthy adults, there is often mild pathology in the kidney. The detection of kidney microstructural variation and pathology by imaging and the clinical pattern associated with these structural findings is unclear.

STUDY DESIGN

Cross-sectional (clinical-pathologic correlation).

SETTING & PARTICIPANTS

Living kidney donors at Mayo Clinic (Minnesota and Arizona sites) and Cleveland Clinic 2000 to 2011.

PREDICTORS

Predonation kidney function, risk factors, and contrast computed tomographic scan of the kidneys. These scans were segmented for cortical volume and medullary volume, reviewed for parenchymal cysts, and scored for kidney surface roughness.

OUTCOMES

Nephrosclerosis (glomerulosclerosis, interstitial fibrosis/tubular atrophy, and arteriosclerosis) and nephron size (glomerular volume, mean profile tubular area, and cortical volume per glomerulus) determined from an implantation biopsy of the kidney cortex at donation.

RESULTS

Among 1,520 living kidney donors, nephrosclerosis associated with increased kidney surface roughness, cysts, and smaller cortical to medullary volume ratio. Larger nephron size (nephron hypertrophy) associated with larger cortical volume. Nephron hypertrophy and larger cortical volume associated with higher systolic blood pressure, glomerular filtration rate, and urine albumin excretion; larger body mass index; higher serum uric acid level; and family history of end-stage renal disease. Both nephron hypertrophy and nephrosclerosis associated with older age and mild hypertension. The net effect of both nephron hypertrophy and nephrosclerosis associating with cortical volume was that nephron hypertrophy diminished volume loss with age-related nephrosclerosis and fully negated volume loss with mild hypertension-related nephrosclerosis.

LIMITATIONS

Kidney donors are selected on health, restricting the spectrum of pathologic findings. Kidney biopsies in living donors are a small tissue sample leading to imprecise estimates of structural findings.

CONCLUSIONS

Among apparently healthy adults, the microstructural findings of nephron hypertrophy and nephrosclerosis differ in their associations with kidney function, macrostructure, and risk factors.

Outcomes of living kidney donors with medullary sponge kidney

BACKGROUND

Patients with medullary sponge kidney (MSK) commonly encounter recurrent nephrolithiasis. The existing knowledge on safety of donors with MSK has not been studied.

METHODS

We conducted a retrospective cohort study at a tertiary referral hospital to assess the outcomes of living kidney donors with MSK. All adults with MSK (N = 26) who underwent nephrectomy as living kidney donors between January 2000 and September 2014 were included. Non-donors with MSK (N = 78) were randomly selected by matching the year of birth and the comorbidity score with a ratio of 1:3 for comparison.

RESULTS

The incident rates of symptomatic stone were 0.7, 0.4 and 4.9 events/100 patient-years in donors, recipients and non-donors, respectively. After adjusting for history of kidney stones and baseline estimated glomerular filtration rate (eGFR), the kidney stone-related event was significantly lower in donors than in non-donors (hazard ratio 0.14; 95% confidence interval 0.01-0.66). One recipient of MSK living donor had symptomatic stone at median follow-up time of 8.4 years (interquartile range 5.6-12.4 years). None of MSK donors had hypercalciuria, hypocitraturia or hyperoxaluria prior to kidney donation. At 5 years after the index surgery date, there was no significant difference in eGFR between donors and non-donors (76.1 versus 70.9 mL/min/1.73 m², P = 0.12).

CONCLUSIONS

These findings are reassuring for the safety of MSK kidney donors with normal kidney function, low kidney stone risk and no significant comorbidity.

Risk of kidney stones with surgical intervention in living kidney donors

A kidney stone in a person with a solitary kidney requires urgent attention, which may result in surgical and/or hospital attention. We conducted a matched retrospective cohort study to determine if living kidney donors compared to healthy nondonors have a higher risk of: (i) kidney stones with surgical intervention, and (ii) hospital encounters for kidney stones. We reviewed all predonation charts for living kidney donations from 1992 to 2009 at five major transplant centers in Ontario, Canada, and linked this information to healthcare databases. We selected nondonors from the healthiest segment of the general population and matched 10 nondonors to every donor. Of the 2019 donors and 20 190 nondonors, none had evidence of kidney stones prior to cohort entry. Median follow-up time was 8.4 years (maximum 19.7 years; loss to follow-up <7%). There was no difference in the rate of kidney stones with surgical intervention in donors compared to nondonors (8.3 vs. 9.7 events/10 000 person-years; rate ratio 0.85; 95% confidence interval [CI] 0.47-1.53). Similarly there was no difference in the rate of hospital encounters for kidney stones (12.1 vs. 16.1 events/10 000 person-years; rate ratio 0.75; 95% CI 0.45-1.24). These interim results are reassuring for the safety of living kidney donation.

Demographic, metabolic, and blood pressure characteristics of living kidney donors spanning five decades

While cautious criteria for selection of living kidney donors are credited for favorable outcomes, recent practice changes may include acceptance of less than ideal donors. To characterize trends in donor acceptance, the Renal and Lung Living Donors Evaluation (RELIVE) Study evaluated 8,951 kidney donors who donated between 1963 and 2007 at three major U.S. transplant centers. Over the study interval, there was an increase in the percentage of donors >40 years old from 38% to 51%; donors >60 years varied between 1% and 4%. The proportion of donors with obesity increased from 8% to 26% and with glucose intolerance from 9% to 25%. The percentage of hypertensive donors was consistent (5-8%). Accepted donors ≥60 years old were more likely to have obesity, glucose intolerance, and/or hypertension compared to younger donors (p<0.0001). Our results demonstrate important trends in acceptance of older and more obese donors. The fraction of older donors accepted with glucose intolerance or hypertension remains small and for the majority includes mild elevations in glucose or blood pressure that were previously classified as within normal limits.

Medical and non-medical factors that affect voluntary living-related kidney donation: A single-center study

The aim was to evaluate the patients with chronic kidney disease stage 5 (CKD 5) and their prospective renal transplant donors with regard to their renal replacement choices, and to assess the medical and non-medical factors that affect living-related renal donor selection. Over 24 months, consecutive patients with CKD 5 and their relatives were interviewed at presentation. Reasons for the choice of modality were analyzed; the prospective recipients and their donors were again interviewed separately and the medical and nonmedical factors that affected the donor selection were determined. A total of 1257 patients were enrolled. Conservative therapy, maintenance dialysis, and renal transplantation were chosen by 513 (40.8%), 320 (25.5%), and 424 (33.7%) patients, respectively. Only socioeconomic status affected the modality chosen. The age, gender, and donor availability did not emerge as significant factors. Patients or donors were likely to withdraw from transplant evaluation due to the absence of a voluntary donor, presence of a male donor, coercion not to donate, and the absence of reimbursement. The commonest cause of rejection of a donor was blood group incompatibility (45.8%), followed by diabetes mellitus (DM) or risk of DM (24%), renal disease (5.9%), hypertension (5.5%), and persistent cross-match positivity (5.1%). To improve donation rates, the donor's spouse should be involved in the early stages of donor evaluation, financial support for the recipient has to be improved, and the apprehensions about complications of nephrectomy among the donors need to be alleyed. Male donors are at increased risk of leaving the program in the evaluation phase.