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

Use of a new end-stage kidney disease risk calculator in the Kidney Disease Improving Global Outcomes guideline to evaluate the impact of different living kidney donor candidate assessments

AIM

The Kidney Disease Improving Global Outcomes (KDIGO) guideline recommends the incorporation of a new risk calculator that quantifies the end-stage kidney disease (ESKD) risk based on a composite profile of risk factors in living kidney donor candidates (LKDC). We compared the ESKD risk estimates in previously declined versus accepted LKDC to evaluate the predictive capacity and potential impact of this tool.

METHODS

Baseline 15 year and lifetime ESKD risk estimates without donation were calculated using the risk calculator for LKDC assessed from two centres between 2007 and 2015. LKDC suitability based on the proposed KDIGO and the existing Caring for Australasians with Renal Impairment national guidelines was compared.

RESULTS

Median 15 year ESKD risk was 0.14% (IQR 0.09-0.31%) in declined LKDC (n=59) versus 0.10% (0.07-0.14%) in accepted LKDC (n=89) (P<0.001). Lifetime risk was similar: 0.39% (0.23-0.80%) versus 0.35% (0.22-0.56%), respectively; however, declined LKDC had a higher 98% risk percentile value (8.19% vs 1.02%) and were more likely to exceed a 1% ESKD risk threshold (15% vs 1%; P<0.01). The calculator captured reasons for declining donation in only 39% of LKDC; 46.9% of LKDC with Caring for Australasians with Renal Impairment contraindications were reclassified as having an acceptable (≤1%) lifetime risk and no KDIGO contraindications, primarily related to a lower pre-donation glomerular filtration rate or controlled hypertension with obesity.

CONCLUSION

Declined LKDC had a higher 15 year but similar lifetime ESKD risk. However, the calculator successfully differentiated declined LKDC with a lifetime risk >1%. This risk calculator appears to complement but not replace clinical evaluation.

Living kidney donation from people at risk of nephrolithiasis, with a focus on the genetic forms

Deciding whether to accept a donor with nephrolithiasis is a multifaceted task because of the challenge of finding enough suitable donors while at the same time ensuring the safety of both donors and recipients. Until not long ago, donors with a history of renal stones or with stones emerging during screening on imaging were not considered ideal, but recent guidelines have adopted less stringent criteria for potential donors at risk of stones. This review goes through the problems that need to be approached to arrive at a wise clinical decision, balancing the safety of donors and recipients with the need to expand the organ pool. The risk of declining renal function and worsening stone formation is examined. Documents (consensus statements, guidelines, etc.) on this issue released by the most important medical societies and organizations are discussed and compared. Specific problems of living kidney donation associated with certain systemic (chronic hypercalcemia due to CYP24A1 gene mutations, primary hyperoxaluria, APRT deficiency) and renal (medullary sponge kidney, cystinuria, distal renal tubular acidosis, Dent's disease, Bartter syndrome, familial hypomagnesemia with hypercalciuria and nephrocalcinosis) Mendelian disorders that cause nephrolithiasis are also addressed.

Glomerular filtration rate: new age- and gender- specific reference ranges and thresholds for living kidney donation

BACKGROUND

There is a need for a large, contemporary, multi-centre series of measured glomerular filtration rates (mGFR) from healthy individuals to determine age- and gender-specific reference ranges for GFR. We aimed to address this and to use the ranges to provide age- and gender-specific advisory GFR thresholds considered acceptable for living kidney donation.

METHODS

Individual-level data including pre-donation mGFR from 2974 prospective living kidney donors from 18 UK renal centres performed between 2003 and 2015 were amalgamated. Age- and gender-specific GFR reference ranges were determined by segmented multiple linear regression and presented as means ± two standard deviations.

RESULTS

Males had a higher GFR than females (92.0 vs 88.1 mL/min/1.73m2, P < 0.0001). Mean mGFR was 100 mL/min/1.73m2 until 35 years of age, following which there was a linear decline that was faster in females compared to males (7.7 vs 6.6 mL/min/1.73m2/decade, P = 0.013); 10.5% of individuals aged > 60 years had a GFR < 60 mL/min/1.73m2. The GFR ranges were used along with other published evidence to provide advisory age- and gender-specific GFR thresholds for living kidney donation.

CONCLUSIONS

These data suggest that GFR declines after 35 years of age, and the decline is faster in females. A significant proportion of the healthy population over 60 years of age have a GFR < 60 mL/min/1.73m2 which may have implications for the definition of chronic kidney disease. Age and gender differences in normal GFR can be used to determine advisory GFR thresholds for living kidney donation.

Comparison of accepted and unaccepted living kidney donors: one-center experience

BACKGROUND

Kidney transplantation from living donors (LD) has stagnated in many countries. This study aimed to check whether correction of LD selection practice could increase the number of kidney transplantations.

METHODS

From January 2003 to December 2012, 241 potential adult LD were evaluated in our hospital. Outcome (mortality and end-stage renal disease-ESRD) of accepted LD (182) was compared with unaccepted (59) donors.

RESULTS

Mortality of LD was comparable with that for the standardized Serbian population (SMR = 1.104; 95% CI (0.730-1.606). Among evaluated potential LD, almost every fourth had been unaccepted, but reasons were modifiable in 42.4% of them. In pre-donation period unaccepted donors were significantly older, measured glomerular filtration rate was lower, with higher 15-year and lifelong projected ESRD risks than accepted donors. Despite this, ten years outcome of both groups LD was similar: none of LD developed ESRD, 9.8% of accepted and 11.8% of unaccepted LD died (p = .803).

CONCLUSIONS

During an average of 101 months of follow-up mortality of accepted LD did not differ significantly as compared to the age standardized Serbian population and none of them developed ESRD. In examination of potential LD, the use of accurate and precise methods for kidney function estimation and the evaluation of risk for ESRD and mortality as well as treatment of modifiable contraindications for kidney donation are necessary.

Pre- and postdonation kidney function in donors of a kidney paired donation with unique criteria for donor glomerular filtration rate - a longitudinal cohort analysis

Baseline predonation estimated GFR (eGFR) appears to predict the risk of postdonation chronic kidney disease in live donors. New KIDGO guidelines recommend an eGFR ≥90 ml/min/1.73 m² as an acceptable level of glomerular filtration rate (GFR) for kidney donation. In the Australian Paired Kidney Exchange (AKX) program, all donors with a raw measured GFR (mGFR) ≥80 ml/min are deemed suitable for donation, but the significance of this selection indicator is unclear. We analysed the first 129 live donors in the AKX program with at least 1-year follow-up linking records in the AKX database and ANZDATA. There were 73 male and 56 female donors; mean (±SD) age was 53 ± 11 years. Predonation eGFR was 94 ± 13 ml/min/1.73 m² , mGFR 99 ± 17 ml/min/1.73 m² and raw mGFR 108 ± 18 ml/min. Baseline eGFR was <80 ml/min/1.73 m² in 19 donors, and <90 ml/min/1.73 m² in 42 donors. At 1 year postdonation eGFR was 68 ± 15 ml/min/1.73 m² and the predicted eGFR at 30 years postdonation was on average 50 (29-83) ml/min/1.73 m² . The hypothetical mean age at end-stage kidney disease was estimated to be 145 (95% CI 120-263) years. Over 30% of AKX live donors would have been excluded from donation using KDIGO guidelines. Using AKX donor guidelines, the majority of donors with predicted eGFR <30 ml/min/1.73 m² 30-year postdonation were aged ≥50 years. Long-term outcome data on AKX donors with low eGFR will need careful monitoring.

Renal function up to the 5th decade of life after nephrectomy in childhood: A literature review

The aim of the present study was to find out if in children ablation of 50% of renal mass may be associated with a progressive renal damage (Brenner's hypothesis). We collected 1035 adult or adolescent survivors who underwent nephrectomy for unilateral oncological or non-oncological causes during childhood. Stratification of all survivors for age revealed that the number of subjects with blood hypertension and/or renal dysfunction (glomerular filtration rate < 90 mL/min per 1.73 m² ) to be significantly higher in survivors ≥30 years old in comparison with younger patients. Available data on long-term renal function after nephrectomy during childhood support the Brenner's hypothesis.

The Risk in Living Kidney Donation

This article examines two questions. (1) If prospective living kidney donors knew of the lifetime risk of end-stage renal disease (ESRD) in their remaining kidney, then would they be as willing to give it up? and (2) What should transplant organizations and physicians be telling those who express an interest in donating a kidney about risk? Based on the principle that prospective donors must be fully informed of the risk, I raise the issue of a possible obstacle to closing the gap between the availability and need of transplantable kidneys. Some strategies are offered to address this problem.

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.

Lifetime risk of end-stage kidney disease in living donors for paediatric kidney transplant recipients in Australia and New Zealand - a retrospective study

Living kidney donors (LKD) for paediatric kidney transplant recipients (KTR) have a heightened motivation to donate for emotional reasons and the clear health benefits to the KTR. We hypothesized that the cohort of LKD for paediatric KTR (LKD-P) includes motivated young parents with a higher lifetime end-stage kidney disease (ESKD) risk compared to adult KTR (LKD-A). Data from the Australia and New Zealand Dialysis and Transplant LKD Registry (2004-2015) was analysed to compare baseline characteristics and predonation ESKD risk in LKD-P (n = 315) versus LKD-A (n = 3448). LKD-P were younger (median age 42 vs. 50 years; P < 0.001) and had a marginally higher lifetime ESKD risk (median 0.44% vs. 0.40%; P < 0.01), with a similar proportion of LKD exceeding 1% risk threshold (5.4% vs. 5.6%; P = NS). Compared to grandparents as LKD-P, parents (median age 41 vs. 59 years; P < 0.001) had a higher lifetime ESKD (0.44% vs. 0.25%; P < 0.001). Although unique benefits to paediatric KTR justify the minor increase in lifetime ESKD risk in young parents, carefully selected grandparents are an alternative LKD-P option, allowing parents to donate for subsequent transplants.

Apolipoprotein L1 and Chronic Kidney Disease Risk in Young Potential Living Kidney Donors

OBJECTIVE

The aim of this study was to develop a novel chronic kidney disease (CKD) risk prediction tool for young potential living kidney donors.

SUMMARY OF BACKGROUND DATA

Living kidney donor selection practices have evolved from examining individual risk factors to a risk calculator incorporating multiple characteristics. Owing to limited long-term data and lack of genetic information, current risk tools lack precision among young potential living kidney donors, particularly African Americans (AAs).

METHODS

We identified a cohort of young adults (18-30 years) with no absolute contraindication to kidney donation from the longitudinal cohort study Coronary Artery Risk Development in Young Adults. Risk associations for CKD (estimated glomerular filtration rate <60 mL/min/1.73 m) were identified and assigned weighted points to calculate risk scores.

RESULTS

A total of 3438 healthy adults were identified [mean age 24.8 years; 48.3% AA; median follow-up 24.9 years (interquartile range: 24.5-25.2)]. For 18-year olds, 25-year projected CKD risk varied by ethnicity and sex even without baseline clinical and genetic abnormalities; risk was 0.30% for European American (EA) women, 0.52% for EA men, 0.52% for AA women, 0.90% for AA men. Among 18-year-old AAs with apolipoprotein L1 gene (APOL1) renal-risk variants without baseline abnormalities, 25-year risk significantly increased: 1.46% for women and 2.53% for men; among those with 2 APOL1 renal-risk variants and baseline abnormalities, 25-year risk was higher: 2.53% to 6.23% for women and 4.35% to 10.58% for men.

CONCLUSIONS

Young AAs were at highest risk for CKD, and APOL1 renal-risk variants drove some of this risk. Understanding the genetic profile of young AA potential living kidney donors in the context of baseline health characteristics may help to inform candidate selection and counseling.

Outcomes of Kidney Donors over 60 Years Old: A Single-Center Cohort Study

AIM

To evaluate outcomes and post-donation kidney function of older living kidney donors (LKD).

METHODS

Retrospective analysis of prospective database including all consecutive LKD undergoing laparoscopic nephrectomy in a single center (09/1998-12/2013). LKD aged ≥60 years were compared to younger LKD. Renal function assessed by creatinine levels and estimated glomerular filtration rates (eGFR). Surgical complications classified according to the Clavien-Dindo classification. Bivariate and multivariate analyses using linear mixed effect models were performed to determine factors (age, gender, hypertension status, BMI, choice of better functioning kidney for donation) that might impinge on renal function after donation.

RESULTS

213 LKD were identified: 49 older (median age: 66 years, range: 60-79) and 164 younger (median age: 46, range: 25-59). Mean operative time (149 vs. 152 min, p = 0.69), conversion to laparotomy (n = 1 vs. 3, p = 0.92), grade III-IV complications (n = 4 vs. 2, p = 0.36) were similar. Older had more grade I-II complications (n = 18 vs. 4, p < 0.001). Despite similar pre-donation eGFR (80 vs. 84 ml/min/1.73 m²), older donors presented significantly lower eGFR during inpatient period (46 vs. 51 ml/min/1.73 m², p = 0.0003), at 1 month (51 vs. 58 ml/min/1.73 m², p = 0.002) and at 1 year (54 vs. 62 ml/min/1.73 m², p = 0.001). Multivariate analysis adjusted to gender, hypertension status, BMI and choice of better functioning kidney for donation showed that at 1 year, age ≥60 affected renal function by a coefficient of 0.91 (p < 0.001).

CONCLUSION

Despite renal function improvement after discharge, LKD ≥ 60 years presented lower eGFR than younger at one year and had more grade I-II surgical complications.

Perceptions, motivations, and concerns about living organ donation among people living with HIV

Recent changes to United States law now permit people living with HIV (PLWH) to donate organs to HIV-infected (HIV+) recipients under research protocols. PLWH may have unique motivations for and concerns about living donation and understanding them is critical to ensuring the integrity of this novel approach to organ transplantation. We conducted in-depth interviews with PLWH from an urban HIV clinic who had previously indicated their willingness to be a living donor. Interviews elicited information on their motivations, perceived benefits, and concerns regarding living donation. Codes were identified inductively and then organized into themes and subthemes. Two coders independently analyzed the interviews and reconciled differences in coding by consensus. Thematic saturation was reached after 20 interviews. Motivations for living donation among PLWH included an altruistic desire to help others as well as HIV-specific motivations including solidarity with potential recipients and a desire to overcome HIV-related stigma. Perceived benefits of living donation included gratification from saving or improving the recipient's life and conferring a sense of normalcy for the HIV+ donor. Concerns about donation included the possibility of a prolonged recovery period, organ failure, and transmission of another strain of the virus to the recipients. PLWH had unique motivations, perceived benefits, and concerns about living donation in addition to those previously identified in the general population. These unique factors should be addressed in research protocols, informed consent processes, and the education and training of independent living donor advocates so that these endeavors are ethically sound.

Did parents have it right all along? Parents, risk, and living kidney donation: Revisiting the arguments for and against parental living donation of kidneys

Historically, living kidney donation has been justified in part by our belief that living donors face minimal risks of subsequent disease. Recent research has brought that presumption into question, particularly for younger donors including parents. In light of this finding, we re-examine many of the traditional arguments both for and against the practice of parental living kidney donation. We then propose an alternative framework in which the burden of having a child with end-stage kidney disease can be considered as an illness experienced by the potential donor parent. We believe this allows a more straightforward, as well as more accurate, assessment of the risks and benefits of donation for the potential parental donor. This assessment might then be used to best inform the decision whether or not to proceed with kidney donation using a shared decision-making model, while reflecting the appropriate ethical roles of both the potential donor and the transplantation program.

Risk of ESRD in prior living kidney donors

We studied End-Stage Renal Disease (ESRD) in living kidney donors (LKDs) who donated in the United States between 1994 and 2016 (n = 123 526), using Organ Procurement and Transplantation Network and Centers for Medicare and Medicaid Services data. Two hundred eighteen LKDs developed ESRD, with a median of 11.1 years between donation and ESRD. Absolute 20-year risk was low but not uniform, with risk associated with race, age, and sex and increasing exponentially over time. LKDs had increased risk of ESRD if they were male (adjusted hazard ratio [aHR]: 1.75, 95% confidence interval [95%CI]: 1.33-2.31), had higher BMI (aHR: 1.34 per 5 kg/m² , 95%CI: 1.10-1.64) or lower estimated GFR (aHR: 0.89 per 10 mL/min, 95% CI: 0.80-0.99), were first-degree relatives of the recipient (parent: [aHR: 2.01, 95% CI: 1.26-3.21]; full sibling [aHR: 1.87, 95%CI: 1.23-2.84]; identical twin [aHR: 19.79, 95%CI: 7.65-51.24]), or lived in lower socioeconomic status neighborhoods at donation (aHR: 0.87 per $10k increase; 95%CI: 0.77-0.99). We found a significant interaction between donation age and race, with higher risk at older ages for white LKDs (aHR: 1.26 per decade, 95%CI: 1.04-1.54), but higher risk at younger ages for black LKDs (aHR: 0.75 per decade, 95%CI: 0.57-0.99). These findings further inform risk assessment of potential LKDs.

Serum potassium and adverse outcomes across the range of kidney function: a CKD Prognosis Consortium meta-analysis

Aims

Both hypo- and hyperkalaemia can have immediate deleterious physiological effects, and less is known about long-term risks. The objective was to determine the risks of all-cause mortality, cardiovascular mortality, and end-stage renal disease associated with potassium levels across the range of kidney function and evaluate for consistency across cohorts in a global consortium.

Methods and results

We performed an individual-level data meta-analysis of 27 international cohorts [10 general population, 7 high cardiovascular risk, and 10 chronic kidney disease (CKD)] in the CKD Prognosis Consortium. We used Cox regression followed by random-effects meta-analysis to assess the relationship between baseline potassium and adverse outcomes, adjusted for demographic and clinical characteristics, overall and across strata of estimated glomerular filtration rate (eGFR) and albuminuria. We included 1 217 986 participants followed up for a mean of 6.9 years. The average age was 55 ± 16 years, average eGFR was 83 ± 23 mL/min/1.73 m2, and 17% had moderate- to-severe increased albuminuria levels. The mean baseline potassium was 4.2 ± 0.4 mmol/L. The risk of serum potassium of >5.5 mmol/L was related to lower eGFR and higher albuminuria. The risk relationship between potassium levels and adverse outcomes was U-shaped, with the lowest risk at serum potassium of 4-4.5 mmol/L. Compared with a reference of 4.2 mmol/L, the adjusted hazard ratio for all-cause mortality was 1.22 [95% confidence interval (CI) 1.15-1.29] at 5.5 mmol/L and 1.49 (95% CI 1.26-1.76) at 3.0 mmol/L. Risks were similar by eGFR, albuminuria, renin-angiotensin-aldosterone system inhibitor use, and across cohorts.

Conclusions

Outpatient potassium levels both above and below the normal range are consistently associated with adverse outcomes, with similar risk relationships across eGFR and albuminuria.

Mortality in Living Kidney Donors With ESRD: A Propensity Score Analysis Using the United States Renal Data System

Introduction

In recent years, data have emerged on the outcomes of living kidney donors who develop end-stage renal disease (ESRD). We aimed to evaluate mortality rates in kidney donors who had initiated dialysis compared with a propensity-matched cohort of dialysis patients without previous kidney donation.

Methods

We used the United States Renal Data System (USRDS) and abstracted 274 previous living kidney donors between 1995 and 2009. There were 609,398 individuals on dialysis without kidney donation. We used propensity score matching to identify 258 donors and 258 nondonors. The time-dependent Cox proportional hazards model was used to compare survival between the 2 matched cohorts.

Results

In the propensity score−matched cohort, mortality was lower in donors compared with nondonors (19% vs. 49%; P < 0.0001). The time-dependent Cox proportional hazards model demonstrated that donors had significantly lower mortality compared with nondonors 0 to 5 years since start of dialysis (hazard ratio [HR]: 0.17; 95% confidence interval [CI] 0.11−0.27; P < 0.0001) and with nondonors 5 to 10 years on dialysis (HR: 0.34; 95% CI: 0.19−0.63; P < 0.001). We were unable to estimate the difference between the 2 groups after 10 years on dialysis with any precision (HR: 0.51; 95% CI: 0.18−1.42; P = 0.20) due to the small sample size.

Conclusion

We observed a lower mortality rate in living kidney donors with ESRD compared with matched nondonors. This data should guide clinicians in the informed consent process with prospective donors.

Long-term risks of kidney living donation: review and position paper by the ERA-EDTA DESCARTES working group

Two recent matched cohort studies from the USA and Norway published in 2014 have raised some concerns related to the long-term safety of kidney living donation. Further studies on the long-term risks of living donation have since been published. In this position paper, Developing Education Science and Care for Renal Transplantation in European States (DESCARTES) board members critically review the literature in an effort to summarize the current knowledge concerning long-term risks of kidney living donation to help physicians for decision-making purposes and for providing information to the prospective live donors. Long-term risk of end-stage renal disease (ESRD) can be partially foreseen by trying to identify donors at risk of developing ‘de novo’ kidney diseases during life post-donation and by predicting lifetime ESRD risk. However, lifetime risk may be difficult to assess in young donors, especially in those having first-degree relatives with ESRD. The study from Norway also found an increased risk of death after living donor nephrectomy, which became visible only after >15 years of post-donation follow-up. However, these findings are likely to be largely the result of an overestimation due to the confounding effect related to a family history of renal disease. DESCARTES board members emphasize the importance of optimal risk–benefit assessment and proper information to the prospective donor, which should also include recommendations on health-promoting behaviour post-donation.

Does Low Birthweight Have an Impact on Living Kidney Donor Outcomes?

INTRODUCTION

Because nearly 30,000 people worldwide become living kidney donors each year, donor safety is of the utmost importance. Recent studies have shown that living kidney donation is associated with an increased relative risk for end-stage renal disease (ESRD). It is essential to determine which donors will be more likely to develop ESRD. One of the risk factors for ESRD in living kidney donors is hypertension and, because there are studies demonstrating that low birthweight is a risk factor for developing hypertension in adult life, we hypothesized that donors with low birthweight may be at higher risk of developing renal disease after donation.

METHODS

Seventy-three living kidney donors were examined. Donors were divided into 2 cohorts: a group with low birthweight and group with normal birthweight. We checked whether the donor birthweight has an impact on the outcome of donor renal function and on the development of hypertension.

RESULTS

Hypertension was observed statistically more frequent in the group with low birthweight (P = .003).

CONCLUSION

Glomerular filtration rate before kidney donation was found to be lower in the low-birthweight group.

Temporal trends, center-level variation, and the impact of prevalent state obesity rates on acceptance of obese living kidney donors

The impact of pre-donation obesity on long-term outcomes of living kidney donors remains controversial. Published guidelines offer varying recommendations regarding BMI (kg/m² ) thresholds for donor acceptance. We examined temporal and center-level variation in BMI of accepted donors across US transplant centers. Using national transplant registry data, we performed multivariate hierarchical logistic regression modeling using pairwise comparisons (overweight, BMI: 25-29.9; mildly obese, BMI: 30-34.9; very obese, BMI: ≥35; versus normal BMI: 18.5-24.9). Metrics of heterogeneity, including median odds ratio (MOR), were calculated. Among 90 013 living kidney donors, 2001-2016, proportions who were very obese decreased and proportions who were mildly obese or overweight increased. Significant center-level heterogeneity was noted in BMI of accepted donors; the MOR varied from 1.10 for overweight to 1.93 for very obese donors. At centers located in the 10 states with the highest general population obesity rates, adjusted odds of very obese donor status were 185% higher (reference: normal BMI) than in states with the lowest obesity rates. Although there is a declining trend in acceptance of very obese living kidney donors, variation across centers is significant. Furthermore, local population obesity rates may affect the decision to accept obese individuals as donors.

History of Childhood Kidney Disease and Risk of Adult End-Stage Renal Disease

BACKGROUND

The long-term risk associated with childhood kidney disease that had not progressed to chronic kidney disease in childhood is unclear. We aimed to estimate the risk of future end-stage renal disease (ESRD) among adolescents who had normal renal function and a history of childhood kidney disease.

METHODS

We conducted a nationwide, population-based, historical cohort study of 1,521,501 Israeli adolescents who were examined before compulsory military service in 1967 through 1997; data were linked to the Israeli ESRD registry. Kidney diseases in childhood included congenital anomalies of the kidney and urinary tract, pyelonephritis, and glomerular disease; all participants included in the primary analysis had normal renal function and no hypertension in adolescence. Cox proportional-hazards models were used to estimate the hazard ratio for ESRD associated with a history of childhood kidney disease.

RESULTS

During 30 years of follow-up, ESRD developed in 2490 persons. A history of any childhood kidney disease was associated with a hazard ratio for ESRD of 4.19 (95% confidence interval [CI], 3.52 to 4.99). The associations between each diagnosis of kidney disease in childhood (congenital anomalies of the kidney and urinary tract, pyelonephritis, and glomerular disease) and the risk of ESRD in adulthood were similar in magnitude (multivariable-adjusted hazard ratios of 5.19 [95% CI, 3.41 to 7.90], 4.03 [95% CI, 3.16 to 5.14], and 3.85 [95% CI, 2.77 to 5.36], respectively). A history of kidney disease in childhood was associated with younger age at the onset of ESRD (hazard ratio for ESRD among adults <40 years of age, 10.40 [95% CI, 7.96 to 13.59]).

CONCLUSIONS

A history of clinically evident kidney disease in childhood, even if renal function was apparently normal in adolescence, was associated with a significantly increased risk of ESRD, which suggests that kidney injury or structural abnormality in childhood has long-term consequences.

Risk Factors for Prognosis in Patients With Severely Decreased GFR

Introduction

Patients with chronic kidney disease (CKD) and estimated glomerular filtration rate (eGFR) <30 ml/min per 1.73 m² (corresponding to CKD stage G4+) comprise a minority of the overall CKD population but have the highest risk for adverse outcomes. Many CKD G4+ patients are older with multiple comorbidities, which may distort associations between risk factors and clinical outcomes.

Methods

We undertook a meta-analysis of risk factors for kidney failure treated with kidney replacement therapy (KRT), cardiovascular disease (CVD) events, and death in participants with CKD G4+ from 28 cohorts (n = 185,024) across the world who were part of the CKD Prognosis Consortium.

Results

In the fully adjusted meta-analysis, risk factors associated with KRT were time-varying CVD, male sex, black race, diabetes, lower eGFR, and higher albuminuria and systolic blood pressure. Age was associated with a lower risk of KRT (adjusted hazard ratio: 0.74; 95% confidence interval: 0.69–0.80) overall, and also in the subgroup of individuals younger than 65 years. The risk factors for CVD events included male sex, history of CVD, diabetes, lower eGFR, higher albuminuria, and the onset of KRT. Systolic blood pressure showed a U-shaped association with CVD events. Risk factors for mortality were similar to those for CVD events but also included smoking. Most risk factors had qualitatively consistent associations across cohorts.

Conclusion

Traditional CVD risk factors are of prognostic value in individuals with an eGFR <30 ml/min per 1.73 m², although the risk estimates vary for kidney and CVD outcomes. These results should encourage interventional studies on correcting risk factors in this high-risk population.

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

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

Renal cortical volume: High correlation with pre- and post-operative renal function in living kidney donors

BACKGROUND

CT volumetry has previously been proposed as an alternative to scintigraphy for the evaluation of pre-donation split renal function and the prediction of post-donation renal function in living kidney donors. The aim of our study was to retrospectively assess the relevance of three CT volumetry techniques for estimating pre-donation kidney function and predicting the risk for chronic kidney disease (CKD) at 1-year post-nephrectomy in a French cohort of living donors using isotopic measures of kidney function.

METHODS

Kidney volume was quantified pre-donation for 105 donors using three methods total parenchymal three-dimensional renal volume (3DRV), total parenchymal renal volume contouring (RVCt), and renal cortical volume (RCoV). Subjects also had a 51Cr-EDTA scintigraphy to measure glomerular filtration rate (mGFR) pre-donation and 1-year after donation. For each volume, we tested for association with mGFR using univariate regression models, and computed receiver operating characteristics analyses to assess their predictive potential of post-donation CKD.

RESULTS

Our population was composed of healthy subjects, who were predominantly female (69%) with a median age at donation of 51yo. Median mGFR was 102 mL/min/1.73 m² at pre-donation and 66 mL/min/1.73 m² 1-year after nephrectomy. The pre-donation median volume of the preserved kidney was 156 cm³, 163 cm³ and 99 cm³ for the 3DRV, RVCt and RCoV methods respectively, with a high correlation observed between each technique (R > 0.84). For all methods, total kidney volume was significantly associated with pre-donation mGFR (P < 0.001). Preserved kidney volume was also strongly correlated with post-donation mGFR (P < 0.0001), with the strongest correlation observed for RCoV (R = 0.60 vs. R = 0.39 and R = 0.51 for 3DRV and RVCt, respectively). Finally, the RCoV method yielded the best predictive value of 1-year post-donation CKD (AUC = 0.80 vs. AUC = 0.76 and 0.70 for RVCt and 3DRV, respectively).

CONCLUSIONS

In our cohort of healthy donors with measured kidney function, cortical volumetry (RCoV) appears as the best volumetric technique to use as a surrogate to scintigraphy for estimating pre-donation split renal function and predicting post-donation renal outcomes.

Chronic kidney disease

Chronic kidney disease (CKD) is defined by persistent urine abnormalities, structural abnormalities or impaired excretory renal function suggestive of a loss of functional nephrons. The majority of patients with CKD are at risk of accelerated cardiovascular disease and death. For those who progress to end-stage renal disease, the limited accessibility to renal replacement therapy is a problem in many parts of the world. Risk factors for the development and progression of CKD include low nephron number at birth, nephron loss due to increasing age and acute or chronic kidney injuries caused by toxic exposures or diseases (for example, obesity and type 2 diabetes mellitus). The management of patients with CKD is focused on early detection or prevention, treatment of the underlying cause (if possible) to curb progression and attention to secondary processes that contribute to ongoing nephron loss. Blood pressure control, inhibition of the renin-angiotensin system and disease-specific interventions are the cornerstones of therapy. CKD complications such as anaemia, metabolic acidosis and secondary hyperparathyroidism affect cardiovascular health and quality of life, and require diagnosis and treatment.

The Adoption of a One-Day Donor Assessment Model in a Living Kidney Donor Transplant Program: A Quality Improvement Project

BACKGROUND

Survival of kidney transplants and their recipients is significantly better after living donor than after deceased donor transplantation. However, historically, Northern Ireland has had a low rate of living donor kidney transplantation. The length and complexity of donor evaluation has been one of the main factors contributing to this pattern.

STUDY DESIGN

Quality improvement project.

SETTINGS & PARTICIPANTS

All people in Northern Ireland expressing an interest in becoming a living kidney donor between 2010 and 2015.

QUALITY IMPROVEMENT INTERVENTION

Potential donors deemed to be suitable after a screening questionnaire attended a comprehensive 1-day evaluation including all investigations that had been previously been implemented across multiple clinical visits.

OUTCOME

Change in rate of living donor transplantation following the quality improvement intervention.

MEASUREMENTS

Demographic data and reasons for nondonation.

RESULTS

431 potential donors underwent a 1-day assessment, with 284 (66%) ultimately donating and 12 (3%) still active in the program. Of the 135 (31%) potential donors who did not donate, 48 were unsuitable due to medical or surgical issues, 2 became pregnant, and 18 withdrew. For 38 (9%) potential donors, intended recipients found an alternative living or deceased donor transplant. For 29 (6%) potential donors, the transplantation did not proceed because of recipient-related issues. The annual rate of living donor kidney transplantation in Northern Ireland increased from a mean of 4.3 per million population (pmp) between 2000 and 2009 to 32.6 pmp between 2011 and 2015.

LIMITATIONS

Single geographical region with a potentially unrepresentative population and health care organization. Retrospective observational study. Paucity of data from the preintervention period.

CONCLUSIONS

Following implementation of a 1-day assessment process, we observed a considerable and sustained increase in the rate of living donor kidney transplantation. Making donor evaluation easier holds promise to increase the number of living donor kidney transplants, potentially optimizing outcomes for both recipients and donors.

Socio-sanitary profile and information for living kidney donors and recipients in three Andalusian hospitals

BACKGROUND

Information provided by health professionals to potential donors and recipients is essential for an autonomous and objective decision to make a living kidney donation.

OBJECTIVES

To determine the characteristics of the information received by living kidney donors and recipients, to find out their socio-sanitary profile, their socio-demographics, financial and labour characteristics, health and the caregiving activity of these donors and recipients.

METHODS

Observational, descriptive and cross-sectional study of the population of living kidney donors and recipients from the University Hospitals Puerta del Mar (Cádiz), Virgen del Rocío (Seville), and the University Hospital Complex of Granada, between 08/04/2014 and 08/06/2015.

RESULTS AND CONCLUSIONS

According to the 40 living kidney donors and their 40 recipients surveyed, it is mainly nephrologists who make people aware and provide information about living kidney donation. Almost half of recipients require more information so the evaluation processes and pre-donation information should be updated. In general, the living kidney donor is female, aged 50, with primary/secondary education, lives with a partner and is related to the kidney recipient. Also, the living kidney donor is in paid employment, is overweight, perceives her health as very good or good, and does not smoke or drink alcohol. However, the typical living kidney recipient is male, aged 44 and has completed secondary school studies and vocational training. Furthermore, he does not work, perceives his health as good or regular, and he is an independent person for activities of daily living.

Apolipoprotein L1 Gene Effects on Kidney Transplantation

The pathogenesis of many common etiologies of nephropathy has been informed by recent molecular genetic breakthroughs. It now is apparent that the ethnic disparity in the risk for nondiabetic chronic kidney disease between African Americans and European Americans is explained largely by variation in the apolipoprotein L1 gene (APOL1). The presence of two APOL1 renal risk variants markedly increases an individual's risk for kidney disease. In transplantation, kidneys from deceased African Americans with two APOL1 renal risk variants have shorter survival intervals after engraftment, regardless of the ethnicity of the recipient. Precision medicine will transform the clinical practice of nephrology and kidney transplantation, and play an important role in the allocation of kidneys from deceased and living kidney donors with recent African ancestry. This article reviews existing data on APOL1 in deceased-donor and living-donor kidney transplantation. It considers the impact of including APOL1 genotyping in decisions on the allocation and discard of deceased-donor kidneys, as well as the selection of living donors.

Lifetime risk of renal replacement therapy in Europe: a population-based study using data from the ERA-EDTA Registry

Background

Upcoming KDIGO guidelines for the evaluation of living kidney donors are expected to move towards a personal risk-based evaluation of potential donors. We present the age and sex-specific lifetime risk of renal replacement therapy (RRT) for end-stage renal disease in 10 European countries.

Methods

We defined lifetime risk of RRT as the cumulative incidence of RRT up to age 90 years. We obtained RRT incidence rates per million population by 5-year age groups and sex using data from the European Renal Association-European Dialysis and Transplant Association (ERA-EDTA) Registry, and used these to estimate the cumulative incidence of RRT, adjusting for competing mortality risk.

Results

Lifetime risk of RRT varied from 0.44% to 2.05% at age 20 years and from 0.17% to 1.59% at age 70 years across countries, and was twice as high in men as in women. Lifetime RRT risk decreased with age, ranging from an average of 0.77% to 0.44% in 20- to- 70-year-old women, and from 1.45% to 0.96% in 20- to- 70-year-old men. The lifetime risk of RRT increased slightly over the past decade, more so in men than in women. However, it appears to have stabilized or even decreased slightly in more recent years.

Conclusions

The lifetime risk of RRT decreased with age, was lower in women as compared with men of equal age and varied considerably throughout Europe. Given the substantial differences in lifetime risk of RRT between the USA and Europe, country-specific estimates should be used in the evaluation and communication of the risk of RRT for potential living kidney donors.

[Outcome of living kidney donors for transplantation]

Nowadays, several treatments exist to treat terminal chronic renal failure. Best results for the recipients are obtained with kidney transplantation concerning mortality and quality of life. Transplantation is also the cheaper option for society. Living kidney donation raises the issue of the becoming of the donor, an absolutely healthy subject who gets to a surgical procedure. The becoming of living kidney donors has been compared with the one of controls subjects in several studies. The evaluations focused on the complications of nephrectomy in the short and long-term: kidney failure, hypertension, proteinuria, possibility of pregnancy, quality of life, and mortality. The first results did not show any risk linked to kidney donation, compared to general population. However, since 2013, kidney donors were found at higher risk for kidney failure and even for mortality, compared with controls selected like donor candidates. The risk of kidney donation is nevertheless acceptable and minimal, on the condition of rigorous selection of candidates and regular follow-up.

Living Kidney Donor Cancellation at King Hussein Medical Center

OBJECTIVES

Living-related kidney donation is the main source of renal grafts in Jordan, since kidneys from deceased donors are scarce. Although the Jordanian community accepts the idea of kidney donation to family members, not all potential donors manage to complete the required psychologic and medical evaluations. We review the causes of kidney-donation cancellation and suggest options to increase the number of available organs.

MATERIALS AND METHODS

We performed a retrospective chart review of all potential living-related kidney donors at King Hussein Medical Center between January 2008 and June 2016.

RESULTS

Of 642 potential donors, 366 (57%) were male and 276 (43%) were female, ranging in age from 18 to 66 years with a mean age of 37 years. A total of 384 (59.8%) eventually donated a kidney. A donor issue was the cause of cancellation in 143 (22.3%), whereas 47 (32.9%) had a risk for renal impairment after donation (eg, hematuria, proteinuria, stones, multiple renal cysts, scarred kidney, congenital malformation, recurrent urinary tract infection), and 30 (21%) had blood group or immunologic incompatibilities. Fifteen (10.5%) withdrew during the evaluation process, 13 (9%) had hypertension, 10 (7%) had a high body mass index, 8 (5.6%) were diabetic or prediabetic, 7 (4.9%) were surgically unsuitable, 4 (2.8%) had hepatitis B virus infection, 4 (2.8%) were pregnant, 3 (2.1%) had significant cardiovascular disease, 1 (0.7%) had splenomegaly with lymph node enlargement, and 1 (0.7%) had thyroiditis.

CONCLUSIONS

Cancellation of kidney donation in Jordan is mainly for medical reasons, the most common being renal issues. Paired donation between blood group and immunologically incompatible duos may increase the number of organs available, as may good psychologic assessment and counseling of those likely to change their mind. Support should be provided for donors who drop out of donation for any cause, especially for renal and vascular issues.

Considering Tangible Benefit for Interdependent Donors: Extending a Risk-Benefit Framework in Donor Selection

From its infancy, live donor transplantation has operated within a framework of acceptable risk to donors. Such a framework presumes that risks of living donation are experienced by the donor while all benefits are realized by the recipient, creating an inequitable distribution that demands minimization of donor risk. We suggest that this risk-tolerance framework ignores tangible benefits to the donor. A previously proposed framework more fully considers potential benefits to the donor and argues that risks and benefits must be balanced. We expand on this approach, and posit that donors sharing a household with and/or caring for a potential transplant patient may realize tangible benefits that are absent in a more distantly related donation (e.g. cousin, nondirected). We term these donors, whose well-being is closely tied to their recipient, "interdependent donors." A flexible risk-benefit model that combines risk assessment with benefits to interdependent donors will contribute to donor evaluation and selection that more accurately reflects what is at stake for donors. In so doing, a risk-benefit framework may allow some donors to accept greater risk in donation decisions.

Anesthesia Management of Organ Donors

The shortage of suitable organs is the biggest obstacle for transplants. At present, most organs for transplant in the United States are from donation after neurologic determination of death (brain death). Potential organs for transplant need to maintain their viability during a series of insults, including the original disease, physiologic derangements during the dying process, ischemia, and reperfusion. Proper donor management before, during, and after procurement has potential to increase the number and quality of organs from donors. Anesthesiologists need to understand the physiologic derangements associated with brain death and the updated donor management during the periprocurement period.

Impact of screening for metabolic syndrome on the evaluation of obese living kidney donors

BACKGROUND

We report our experience with metabolic syndrome screening for obese living kidney donor candidates to mitigate the long-term risk of CKD.

METHODS

We retrospectively reviewed 814 obese (BMI≥30) and 993 nonobese living kidney donor evaluations over 12 years. Using logistic regression, we explored interactions between social/clinical variables and candidate acceptance before and after policy implementation.

RESULTS

Obese donor candidate acceptance decreased after metabolic syndrome screening began (56.3%, 46.3%, p < 0.01), while nonobese candidate acceptance remained similar (59.6%, 59.2%, p = 0.59). Adjusting for age, gender, race, BMI, and number of prior evaluations, acceptance of obese candidates decreased significantly more than nonobese (p = 0.025). In candidates without metabolic syndrome, there was no significant change in how age, sex, race, or BMI affected a donor candidate's probability of acceptance.

CONCLUSION

Metabolic syndrome screening is a simple stratification tool for centers with liberal absolute BMI cut-offs to exclude potentially higher-risk obese candidates.

Lifetime risks of kidney donation: a medical decision analysis

OBJECTIVE

This study estimated the potential loss of life and the lifetime cumulative risk of end-stage renal disease (ESRD) from live kidney donation.

DESIGN

Markov medical decision analysis.

SETTING

USA.

PARTICIPANTS

40-year-old live kidney donors of both sexes and black/white race.

INTERVENTION

Live donor nephrectomy.

MAIN OUTCOME AND MEASURES

Potential remaining life years lost, quality-adjusted life years (QALYs) lost and added lifetime cumulative risk of ESRD from donation.

RESULTS

Overall 0.532-0.884 remaining life years were lost from donating a kidney. This was equivalent to 1.20%-2.34% of remaining life years (or 0.76%-1.51% remaining QALYs). The risk was higher in male and black individuals. The study showed that 1%-5% of average-age current live kidney donors might develop ESRD as a result of nephrectomy. The added risk of ESRD resulted in a loss of only 0.126-0.344 remaining life years. Most of the loss of life was predicted to be associated with chronic kidney disease (CKD) not ESRD. Most events occurred 25 or more years after donation. Reducing the increased risk of death associated with CKD had a modest overall effect on the per cent loss of remaining life years (0.72%-1.9%) and QALYs (0.58%-1.33%). Smoking and obesity reduced life expectancy and increased overall lifetime risks of ESRD in non-donors. However the percentage loss of remaining life years from donation was not very different in those with or without these risk factors.

CONCLUSION

Live kidney donation may reduce life expectancy by 0.5-1 year in most donors. The development of ESRD in donors may not be the only measure of risk as most of the predicted loss of life predates ESRD. The study identifies the potential importance of following donors and treating risk factors aggressively to prevent ESRD and to improve donor survival.