Long-term renal function and cardiovascular disease risk in obese kidney donors

Bariatric Surgery in Severely Obese Kidney Donors Before Kidney Transplantation: A Retrospective Study

BACKGROUND

Bariatric surgery (BS) is the optimal approach for sustained weight loss and may alter donation candidacy in potential donors with obesity. We evaluated the long-term effects of nephrectomy after BS on metabolic profile, including body mass index, serum lipids and diabetes, and kidney function of donors.

METHODS

This was a single-center retrospective study. Live kidney donors who underwent BS before nephrectomy were matched for age, gender, and body mass index with patients who underwent BS alone and with donors who underwent nephrectomy alone. Estimated glomerular filtration rate (eGFR) was calculated according to Chronic Kidney Disease Epidemiology Collaboration and adjusted to individual body surface area to create absolute eGFR.

RESULTS

Twenty-three patients who underwent BS before kidney donation were matched to 46 controls who underwent BS alone. At the last follow-up, the study group showed significantly worse lipid profile with low-density lipoprotein of 115 ± 25 mg/dL versus the control group with low-density lipoprotein of 99 ± 29 mg/dL ( P  = 0.036) and mean total cholesterol of 191 ± 32 versus 174 ± 33 mg/dL ( P  = 0.046). The second control group of matched nonobese kidney donors (n = 72) had similar serum creatinine, eGFR, and absolute eGFR as the study group before nephrectomy and 1 y after the procedure. At the end of follow-up, the study group had significantly higher absolute eGFR compared with the control group (86 ± 21 versus 76 ± 18 mL/min; P  = 0.02) and similar serum creatinine and eGFR.

CONCLUSIONS

BS before live kidney donation is a safe procedure that could increase the donor pool and improve their health in the long run. Donors should be encouraged to maintain their weight and avoid adverse lipid profile and hyperfiltration.

Change in Body Mass Index and Attributable Risk of New-Onset Hypertension Among Obese Living Kidney Donors

OBJECTIVE

To examine whether body mass index (BMI) changes modify the association between kidney donation and incident hypertension.

BACKGROUND

Obesity increases hypertension risk in both general and living kidney donor (LKD) populations. Donation-attributable risk in the context of obesity, and whether weight change modifies that risk, is unknown.

METHODS

Nested case-control study among 1558 adult LKDs (1976-2020) with obesity (median follow-up: 3.6 years; interquartile range: 2.0-9.4) and 3783 adults with obesity in the Coronary Artery Risk Development in Young Adults (CARDIA) and Atherosclerosis Risk in Communities (ARIC) studies (9.2 y; interquartile range: 5.3-15.8). Hypertension incidence was compared by donor status using conditional logistic regression, with BMI change investigated for effect modification.

RESULTS

Overall, LKDs and nondonors had similar hypertension incidence [incidence rate ratio (IRR): 1.16, 95% confidence interval (95% CI): 0.94-1.43, P =0.16], even after adjusting for BMI change (IRR: 1.25, 95% CI: 0.99-1.58, P =0.05). Although LKDs and nondonors who lost >5% BMI had comparable hypertension incidence (IRR: 0.78, 95% CI: 0.46-1.34, P =0.36), there was a significant interaction between donor and >5% BMI gain (multiplicative interaction IRR: 1.62, 95% CI: 1.15-2.29, P =0.006; relative excess risk due to interaction: 0.90, 95% CI: 0.24-1.56, P =0.007), such that LKDs who gained weight had higher hypertension incidence than similar nondonors (IRR: 1.83, 95% CI: 1.32-2.53, P <0.001).

CONCLUSIONS

Overall, LKDs and nondonors with obesity had similar hypertension incidence. Weight stability and loss were associated with similar hypertension incidence by donor status. However, LKDs who gained >5% saw increased hypertension incidence versus similar nondonors, providing support for counseling potential LKDs with obesity on weight management postdonation.

Recommendations for living donor kidney transplantation

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

Donor obesity and weight gain after transplantation: two still overlooked threats to long-term graft survival

The effect of donor obesity on kidney transplantation success has long been an overlooked clinical research area. Even though there is no strict guideline in most countries prohibiting donation from obese individuals, most candidates with a body mass index >35-40 kg/m² are rejected due to concerns regarding long-term renal functional deterioration in the donor. The effects of excessive fat mass on renal function and allograft survival have been analysed by several longitudinal and follow-up studies. These studies have documented the deleterious effect on long-term graft outcomes of excessive body mass in living kidney donors and de novo obesity or pre-existing obesity worsening after transplantation on kidney outcomes. However, there is a paucity of clinical trials aimed at countering overweight and obesity in living and deceased kidney donors and in transplant patients. In this review we will briefly discuss the mechanism whereby fat excess induces adverse kidney outcomes and describe the effects on graft function and survival in living obese donors.

Risks for donors associated with living kidney donation: meta-analysis

BACKGROUND

Living kidney donation risk is likely to differ according to donor's demographics. We aimed to analyse the effects of age, sex, body mass index (BMI) and ethnicity.

METHODS

A systematic review and meta-analysis was undertaken of the effects of preoperative patient characteristics on donor kidney function outcomes, surgical complications, and hypertension.

RESULTS

5129 studies were identified, of which 31 met the inclusion criteria, mainly from the USA and Europe. The estimated glomerular filtration rate (eGFR) in donors aged over 60 years was a mean of 9.54 ml per min per 1.73 m2 lower than that of younger donors (P < 0.001). Female donors had higher relative short- and long-term survival. BMI of over 30 kg/m2 was found to significantly lower the donor's eGFR 1 year after donation: the eGFR of obese donors was lower than that of non-obese patients by a mean of -2.70 (95 per cent c.i. -3.24 to -2.15) ml per min per 1.73 m2 (P < 0.001). Obesity was also associated with higher blood pressure both before and 1 year after donation, and a higher level of proteinuria, but had no impact on operative complications. In the long term, African donors were more likely to develop end-stage renal disease than Caucasians.

CONCLUSION

Obesity and male sex were associated with inferior outcomes. Older donors (aged over 60 years) have a larger eGFR decline than younger donors, and African donors have a higher incidence of ESRD than Caucasians.

Practice Patterns in the Acceptance of Medically Complex Living Kidney Donors with Obesity, Hypertension, Family History of Kidney Disease, or Donor-Recipient Age Discrepancy

Background  To assess the practice patterns of the acceptance of medically complex living kidney donors (MCLKDs).

Methods  We distributed a survey to nephrologists and transplant surgeons (TS) across the world through major international transplant societies. The survey contained questions regarding obesity, abnormal blood glucose profile, mild hypertension, donor-recipient age discrepancy, or family history of kidney disease of unknown etiology.

Results  In total, 239 respondents from 29 countries (42% were nephrologists and 58% were TS).

Most respondents would allow donations from obese donors, especially if they intended to lose weight but would be cautious if these donors had abnormal blood glucose or family history of diabetes mellitus. In hypertensive donors, future pregnancy plans mattered in decisions regarding the acceptance of female donors. Most respondents would allow young donors but would be more cautious if they had a future risk of hypertension or a family history of kidney disease of unknown etiology. They would also allow donations from an older person if prolonged waiting time was anticipated. We found multiple areas of consensus of practice among the diverse members of international transplant societies, with some interesting variations among nephrologists and TS.

Conclusions  This survey highlights the practice patterns of the acceptance of MCLKDs among the international community. In the absence of clear guidelines, this survey provides additional information to counsel kidney donors with these conditions.

Hypertension and obesity in living kidney donors

Over the past few decades, the shortage in the kidney donor pool as compared to the increasing number of candidates on the kidney transplant waitlist led to loosening of kidney donors’ acceptance criteria. Hypertension and obesity represent risk factors for chronic kidney disease, both in native kidneys and those in kidney transplant recipients. While great progress has been made in kidney transplantation from living donors to benefit the recipient survival and quality of life, progress has been slow to fully risk-characterize the donors. This review critically reassesses the current state of understanding regarding the risk of end-stage kidney disease in those donors with obesity, hypertension or both. Accurate risk assessment tools need to be developed urgently to fully understand the risk glomerular filtration rate compensation failure in the remaining kidney of the donors.

Feasible kidney donation with living marginal donors, including diabetes mellitus

Objectives

To compare the donor outcomes of living donor kidney transplantation between standard donors (SDs) and marginal donors (MDs) including diabetic patients (MD + DM).

Methods

MDs were defined according to Japanese guideline criteria: (a) age >70‐years, (b) blood pressure ≤130/80 mmHg on hypertension medicine, (c) body mass index >25 to ≤32 kg/m², (d) 24‐h creatinine clearance ≥70 to <80 ml/min/1.73 m², and (e) hemoglobin A1c > 6.2 or ≤6.5 with oral diabetic medicine. Fifty‐three of 114 donors were MDs. We compared donor kidney functions until 60 months postoperatively.

Results

No kidney function parameters were different between SDs and MDs. When comparing SD and MD + DM, MD + DM had a lower postoperative eGFR (48 vs. 41 (1 (month), p = .02), 49 vs. 40 (12, p < .01), 48 vs. 42 (24, p = .04), 47 vs. 38 (36, p = .01)) and the percentage of residual eGFR (SD vs. MD + DM: 63 vs. 57 (1 (month), p < .01), 63 vs. 57 (2, p < .01), 64 vs. 56 (12, p < .01), 63 vs. 57 (24, p < .01), 63 vs. 52 (36, p = .02)). However, when MD with a single risk factor of DM was compared to SD, the difference disappeared. Nine out of 12 (75%) MD + DM had ≥2 risk factors.

Conclusions

Although long‐term observation of donor kidney function is necessary, careful MD + DM selection had the potential to expand the donor pool.

The relationship between serum uric acid levels and development of obesity in living kidney donors after donor nephrectomy

BACKGROUND

Hyperuricaemia plays a role in the pathogenesis of obesity and related metabolic disorders. The aim of this study to investigate the relationship between pre-donation serum uric acid (SUA) level and obesity development after nephrectomy in living kidney donors.

METHODS

Living donors of kidney transplants between 1998 and 2019 were evaluated. Donors with less than 1 year of follow-up were excluded from the study. The participants were divided into two groups according to last control body mass index (BMI) (obese; ≥ 30 kg/m² and nonobese; <30 kg/m² ) and median baseline SUA level (<4.6 mg/dL and ≥4.6 mg/dL).

RESULTS

In the included 240 donors, the mean follow-up was 50 ± 44 (12-216) months. The mean age was 47 ± 11 (19-82) years, and 46.6% of donors were male. At last control, the percentage of obese donors had increased significantly compared to pre-donation time (22.5% vs 33.8%; P < .001) and last control obese donors had both higher baseline SUA (5.1 ± 1.4 vs 4.5 ± 1.2; P < .01) and BMI (30.7 ± 2.6 vs 24.8 ± 3.0; P < .001). Cox regression analysis showed that there is an independent relationship between the baseline SUA level and development of obesity (odds ratio: 1.30 [CI; 1.12-1.50]; P < .001). In Kaplan-Meier analysis, the development of obesity was significantly higher in kidney donors with high SUA level.

CONCLUSION

Living kidney donors (LKD) have a tendency to obesity after nephrectomy. Preoperative serum uric acid level gives important information in LKDs that it could foresee the development of obesity after donation.

Obesity is a risk factor for progression to kidney transplant waitlisting after liver transplantation

BACKGROUND

Non-alcoholic steatohepatitis has emerged as a leading cause of cirrhosis, and obesity-associated comorbidities, including renal disease, have increased in prevalence. Obesity predisposes the kidney to hyperfiltration injury, potentially impairing acute kidney injury recovery. Identification of patients at risk for renal dysfunction is impeded by poor performance of renal function estimating equations among cirrhotics. To better understand obesity among cirrhotics and renal disease progression, we examined likelihood of kidney transplantation (KT) waitlisting after liver transplant alone (LTA) by obesity class.

METHODS

68 607 LTA recipients were identified in SRTR (2005-2018). Fine and Gray competing risks models were used to analyze likelihood of KT waitlisting.

RESULTS

27.4% of recipients were obese (BMI ≥ 30 kg/m² ) and were 10% more likely to require KT waitlisting (aHR: 1.10, 95%CI: 1.01-1.20). Risk was highest among recipients with Classes II and III obesity (BMI: ≥35 kg/m² ) (aHR: 1.37, 95%CI: 1.17-1.56). Moreover, recipients with Classes II and III obesity were 57% more likely to require KT waitlisting within one year post-LTA (aHR: 1.57, 95%CI: 1.18-2.10) compared to non-obese recipients.

DISCUSSION

These findings suggest obesity was a risk factor for renal recovery failure and/or renal disease progression post-LTA and may confound identification of renal dysfunction and/or prediction of renal recovery among cirrhotics.

Mayo Adhesive Probability (MAP) score of non-donated kidney aids in predicting post-operative renal function following donor nephrectomy

Background

To examine the association of preoperative Mayo Adhesive Probability (MAP) scores in the donor (MAP_d) and non-donor kidneys (MAP_nd) with post-donation renal function.

Methods

Three hundred thirty-one patients undergoing hand assisted laparoscopic donor nephrectomy (HALDN) were reviewed. MAP_d and MAP_nd were obtained. Estimated glomerular filtration rate (eGFR) was recorded preoperatively and at 1 day, 1 month, and 6 months postoperatively.

Results

Two hundred females and 131 males were evaluated with median BMI 26.4 kg/m² (range 17.1–39.6) and median age 45 years (range 19–78). MAP_d score was 0 for 231 patients (69.8%) and > 0 for 100 patients (30.2%). MAP_nd score was 0 for 234 patients (70.7%) and > 0 for 97 patients (29.3%). The median preoperative eGFR was 86.6 ml/min/1.73m² (range 48.8–138.4). After adjusting for preoperative eGFR, BMI, ASA score, and kidney sidedness, postoperative eGFR was associated with MAP score in the non-donated kidney (p = 0.014) but not in the donated kidney (p = 0.24). Compared to donors with MAP_nd = 0, donors with a MAP_nd > 0, mean eGFR was − 2.33 ml/min/1.73m² lower at postoperative day 1 (95% CI − 4.24 to − 0.41, p = 0.018), − 3.02 ml/min/1.73m² lower at 1 month (95% CI − 5.11 to − 0.93, p = 0.005), and − 2.63 ml/min/1.73m² lower at 6 months postoperatively (95% CI − 5.01 to − 0.26, p = 0.030).

Conclusions

MAP score > 0 in the non-donated kidney is associated with worse renal function in the 6 months following HALDN.

Bariatric surgery for prospective living kidney donors with obesity?

The obesity epidemic has gripped the transplant community. With nearly 40% of adults in the United States being obese (BMI ≥30 kg/m² ) and 20% being morbidly obese (BMI ≥35 kg/m² ), the implications for both donors and recipients of solid organs continue to grow.¹ Nowhere is this more impactful than the candidacy of living kidney donors (LKDs). As increasing numbers of obese adults present for LKD consideration and evidence of inferior outcomes among obese LKDs grows, transplant surgeons will become progressively challenged by how to manage these patients in the clinic. Therefore, we offer this Personal Viewpoint to the transplant surgery community in order to review the current impact of obesity on living kidney donation, highlight what weight-loss interventions have already been attempted, and discuss the role that referral for weight-loss interventions including bariatric surgery might have going forward.

Implications of excess weight on kidney donation: Long-term consequences of donor nephrectomy in obese donors

BACKGROUND

An elevated body mass index (>30 kg/m²) has been a relative contraindication for living kidney donation; however, such donors have become more common. Given the association between obesity and development of diabetes, hypertension, and end-stage renal disease, there is concern about the long-term health of obese donors.

METHODS

Donor and recipient demographics, intraoperative parameters, complications, and short- and long-term outcomes were compared between contemporaneous donors-obese donors (body mass index ≥30 kg/m²) versus nonobese donors (body mass index <30 kg/m²).

RESULTS

Between the years 1975 and 2014, we performed 3,752 donor nephrectomies; 656 (17.5%) were obese donors. On univariate analysis, obese donors were more likely to be older (P < .01) and African American (P < .01) and were less likely to be a smoker at the time of donation (P = .01). Estimated glomerular filtration rate at donation was higher in obese donors (115 ± 36 mL/min/1.73m²) versus nonobese donors (97 ± 22 mL/min/1.73m²; P < .001). There was no difference between groups in intraoperative and postoperative complications; but intraoperative time was longer for obese donors (adjusted P < .001). Adjusted postoperative length of stay (LOS) was longer (adjusted P = .01), but after adjustment for donation year, incision type, age, sex, and race, there were no differences in short-term (<30 days) and long-term (>30 days) readmissions. Estimated glomerular filtration rate and rates of end-stage renal disease were not significantly different between donor groups >20 years after donation (P = .71). However, long-term development of diabetes mellitus (adjusted hazard ratio (HR) 3.14; P < .001) and hypertension (adjusted hazard ratio (HR) 1.75; P < .001) was greater among obese donors and both occurred earlier (diabetes mellitus: 12 vs 18 years postnephrectomy; hypertension: 11 vs 15 years).

CONCLUSION

Obese donors develop diabetes mellitus and hypertension more frequently and earlier than nonobese donors after donation, raising concerns about increased rates of end-stage renal disease.

Long-Term Consequences of Complex Living Renal Donation: Is It Safe?

INTRODUCTION

As there is a paucity of literature regarding the long-term outcomes of complex living donors, we conducted this study to assess the effect of kidney donation on the complex living kidney donor.

MATERIALS AND METHODS

This retrospective study was conducted in Narayan Health Hospital, Kolkata, Eastern India. The cohort consisted of complex living kidney donors who donated kidneys between the years 2007 and 2012. All donors were 60 years old or older, or were younger than 60 years and had comorbidities like hypertension and obesity. After a minimum follow-up of 5 years, all donors underwent evaluation. Data pertaining to hypertension, new-onset diabetes, body mass index (BMI), estimated glomerular filtration rate (eGFR) and albuminuria, and cardiac events were compared from the time of donation till 5 years post-transplant.

RESULTS AND DISCUSSION

We found a statistically significant increase in blood pressure, number of antihypertensives used, and mean BMI at follow-up. Diabetes mellitus was developed in 22.3% of donors. The mean GFR also decreased significantly at follow-up. There were 42 elderly donors (≥60 years) and 23 ≤ 59 years of age. There was a significant fall of eGFR in both groups, but the percentage fall was similar in both groups. A significant percentage of donors developed proteinuria, the majority being hypertensives.

CONCLUSION

Procurement of kidneys from marginal donors should be done cautiously, and donors should be assessed for morbidity and mortality in the future, as we found a statistically significant deterioration in renal function, blood pressure, and BMI over long-term follow-up.

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.

Live donor study - implications of kidney donation on cardiovascular risk with a focus on lipid parameters including lipoprotein a

In this prospective observational cohort study, we evaluate the change in cardiovascular risk parameters, with a focus on lipids, in live kidney donors 1 year post donation. Body mass index, systolic/diastolic blood pressure, kidney function (chromium-51 ethylenediaminetetraacetic acid estimated glomerular filtration) and lipid parameters were measured at baseline and 1 year. Data on 87 live kidney donors were collected. Body mass index increased from 26.5 ± 2.7 pre to 27.4 ± 3.0 kg/m(2) post donation (p < 0.0001). Chromium-51 ethylenediaminetetraacetic acid estimated glomerular filtration decreased from 111.8 ± 20.0 pre to 72.1 ± 13.1 mL/min/1.73 m(2) post donation (p < 0.0001). Serum triglyceride levels increased from 0.8 (interquartile range 0.6-1.3) pre to 1.0 mmol/L (interquartile range 0.7-1.6) post donation (p = 0.0004). Statin use increased from 11.5% pre to 21% post donation (p < 0.005). Low-density lipoprotein remained stable, and other lipids (high-density lipoprotein, apolipoprotein B and lipoprotein a) did not change post donation.

Long-Term Body Mass Index Trends After Living-Donor Nephrectomy

OBJECTIVES

As the demand for kidney transplant allografts has increased, many centers are expanding the upper limit of acceptable body mass index for kidney donors. However, obesity is a risk factor for developing renal disease. Our goal was to quantify body mass index trends in donor nephrectomy patients and to institute nutrition counseling to promote sustainable weight loss to reduce the risk of metabolic syndrome-derived renal dysfunction.

MATERIALS AND METHODS

Ninety patients who underwent donor nephrectomy between 2007 and 2012 consented to having height and weight data collected at multiple time points. After data collection, each patient underwent a standardized nutrition counseling session. One year later, body mass index was reassessed.

RESULTS

Preoperatively, 52% of the patients were overweight or obese. The percentage of overweight and obese patients remained stable for 2 years after surgery. However, at 3, 4, and 5 years after surgery, these rates increased to 59%, 69%, and 91%. Each patient was counseled about obesity-related comorbidities and provided information about lifestyle modification. One year later, 94% of previously overweight patients and 82% of previously obese patients had a decrease in mean body mass index from 27.2 ± 4.0 kg/m2 to 25.1 ± 3.6 kg/m2.

CONCLUSIONS

Living-donor nephrectomy patients are at risk of developing obesity, similar to the adult population. Nutrition counseling may be beneficial to help normalize body mass index in patients who have become overweight or obese to potentially prevent obesity-related comorbidities. All patients were evaluated by a nutrition specialist after surgery to review our donor nephrectomy nutrition brochure. Body mass index monitoring and primary care follow-up appear to be appropriate surveillance methods.

Selection and Postoperative Care of the Living Donor

Live organ donors typically consult their primary care providers when considering live donation and then return for follow-up after surgery and for ongoing primary care. Live liver and kidney transplants are performed routinely as a method to shorten the waiting time for a recipient, provide a healthy organ for transplant, and increase recipient survival. Careful medical and psychosocial evaluation of the potential donor is imperative to minimize harm. This evaluation must be performed by an experienced live donor medical team. Routine health care with careful attention to weight maintenance, cardiovascular health, and prevention of diabetes and hypertension is paramount.

Donor Contraindications to Living Kidney Donation: A Single-Center Experience

OBJECTIVE

Kidney transplantation is the treatment of choice in end-stage renal disease. In Turkey, the inadequate cadaveric donor supply has resulted in transplantation from living kidney donors (LKD) in 80% of transplant operations. LKD candidates undergo a thorough general medical evaluation and are approved to donate their kidneys only if no contraindication is found. In our study we aimed to investigate the reasons and rate of denial for living kidney donation in our center.

METHODS

We included all LKD candidates who applied to our center between June 2012 to June 2014. Demographic data, rate of rejection, and the reasons for denial to organ donation were analyzed retrospectively.

RESULTS

Of the 97 LKD candidates included in the study, 60 (62%) were unable to donate their kidneys. Among the reasons for denial were hypertension with target organ damage in 30% (n = 18), immunologic reasons in 23% (n = 14), impaired renal function in 20% (n = 12) cardiovascular reasons 13.3% (n = 8), diabetes mellitus in 10% (n = 6), malignity in 10% (n = 6), obesity (body mass index > 35 kg/m(2)) in 5% (n = 3), and miscellaneous in 18.3% (n = 11). There were >1 reasons in 13 candidates.

CONCLUSIONS

The problems detected in donor candidates offer a possibility for early detection of disorders and increased awareness.

LOng-term follow-up after liVE kidney donation (LOVE) study: a longitudinal comparison study protocol

Background

The benefits of live donor kidney transplantation must be balanced against the potential harm to the donor. Well-designed prospective studies are needed to study the long-term consequences of kidney donation.

Methods

The “LOng-term follow-up after liVE kidney donation” (LOVE) study is a single center longitudinal cohort study on long-term consequences after living kidney donation. We will study individuals who have donated a kidney from 1981 through 2010 in the Erasmus University Medical Center in Rotterdam, The Netherlands. In this time period, 1092 individuals donated a kidney and contact information is available for all individuals. Each participating donor will be matched (1:4) to non-donors derived from the population-based cohort studies of the Rotterdam Study and the Study of Health in Pomerania. Matching will be based on baseline age, gender, BMI, ethnicity, kidney function, blood pressure, pre-existing co-morbidity, smoking, the use of alcohol and highest education degree. Follow-up data is collected on kidney function, kidney-related comorbidity, mortality, quality of life and psychological outcomes in all participants.

Discussion

This study will provide evidence on the long-term consequences of live kidney donation for the donor compared to matched non-donors and evaluate the current donor eligibility criteria.

Trial registration

Dutch Trial Register NTR3795.

Weight trends in United States living kidney donors: Analysis of the UNOS database

AIM: To analyze the national trends associated with body mass index (BMI) and living kidney donation.

METHODS: Forty-seven thousand seven hundred and five adult living kidney donors as reported to the Organ Procurement and Transplantation Network from 1999 to 2011 were analyzed using their pre-donation BMI. Predictor variables of interest included age, gender, ethnicity, relationship, education status, and transplant region.

RESULTS: Sixteen thousand nine hundred and seventy-one of the living kidney donors were normal weight (35.6%); 19337 were overweight (40.5%); 9007 were mildly obese (18.9%); 1992 were moderate to morbidly obese (4.2%). Overweight and mildly obese kidney donors have increased through time by 12% and 20% every 5 years, respectively (P < 0.05). Donors 35-49 years of age, hispanic males or females and black females, those with high school diploma or general Education Degree, and biologically related or partner/spouses were more likely to be obese.

CONCLUSION: Over the past 13 years, the majority of living kidney donors have spanned the overweight to obese categories. Paralleling the national rise is an increase in overweight and mildly obese kidney donors. A fair number of moderate to morbidly obese living kidney donors are still allowed to donate.

Choosing the order of deceased donor and living donor kidney transplantation in pediatric recipients: a Markov decision process model

BACKGROUND

Most pediatric kidney transplant recipients eventually require retransplantation, and the most advantageous timing strategy regarding deceased and living donor transplantation in candidates with only 1 living donor remains unclear.

METHODS

A patient-oriented Markov decision process model was designed to compare, for a given patient with 1 living donor, living-donor-first followed if necessary by deceased donor retransplantation versus deceased-donor-first followed if necessary by living donor (if still able to donate) or deceased donor (if not) retransplantation. Based on Scientific Registry of Transplant Recipients data, the model was designed to account for waitlist, graft, and patient survival, sensitization, increased risk of graft failure seen during late adolescence, and differential deceased donor waiting times based on pediatric priority allocation policies. Based on national cohort data, the model was also designed to account for aging or disease development, leading to ineligibility of the living donor over time.

RESULTS

Given a set of candidate and living donor characteristics, the Markov model provides the expected patient survival over a time horizon of 20 years. For the most highly sensitized patients (panel reactive antibody > 80%), a deceased-donor-first strategy was advantageous, but for all other patients (panel reactive antibody < 80%), a living-donor-first strategy was recommended.

CONCLUSIONS

This Markov model illustrates how patients, families, and providers can be provided information and predictions regarding the most advantageous use of deceased donor versus living donor transplantation for pediatric recipients.

Obesity Correlates With Glomerulomegaly But Is Not Associated With Kidney Dysfunction Early After Donation

BACKGROUND

Body mass index (BMI) is a convenient measure used to assess obesity and is used to select candidates for kidney donation. Glomerulomegaly is an early indicator of obesity-related kidney disease. Whether obesity assessment by BMI best reflects underlying glomerulomegaly and is predictive of adverse changes in renal function postdonation is unclear.

METHODS

We performed a retrospective study on a cohort of 1065 living donors at the Mayo Clinic in Rochester; obesity measures by BMI and by computed tomography were compared between 20 donors with largest to 20 donors with the smallest glomerular volumes (on implantation biopsy). In addition, the change in kidney function postdonation (mean 7 months) was compared across BMI groups (<25, 25-29, 30-34, ≥35 kg/m²) in about 500 donors.

RESULTS

We observed that larger glomerular volume was more strongly associated with BMI per standard deviation (SD) (odds ratio [OR] =5.0, P = 0.002) than waist circumference/height² per SD (OR = 3.9, P = 0.02), visceral fat/height² per SD (OR = 2.4, P = 0.02), subcutaneous fat/height² per SD (OR = 2.0, P = 0.06), renal hilar fat/height² per SD (OR = 1.6, P = 0.19), or peri/pararenal fat/height² per SD (OR = 1.5, P = 0.23). Postdonation changes in glomerular filtration rate, blood pressure, and albuminuria were similar across BMI categories.

CONCLUSIONS

The BMI outperforms various computed tomography measures of abdominal fat in detecting obesity-related glomerulomegaly. Despite this strong association with glomerulomegaly, short-term renal function outcomes are similar across BMI categories. Long-term follow-up is required to definitively define the impact of obesity on kidney function after donation.

Risk factors for perioperative complications in hand-assisted laparoscopic donor nephrectomy

Living donor kidney transplant is the preferred treatment for end-stage renal disease; however, the shortage of kidney donors remains a big problem. One of the major reasons for the shortage of living donors is the risk of potentially serious surgical complications of a procedure in which the donor has no personal medical benefit. Therefore it is important to understand the risk factors for perioperative complications associated with donor nephrectomy. Hand-assisted laparoscopic donor nephrectomy is the preferred approach for kidney procurement in many medical centers. This review gives an overview of the risk factors in donor nephrectomy and more specifically in hand-assisted laparoscopic donor nephrectomy.

Long term prospective assessment of living kidney donors: single center experience

Virtually, all studies reporting the outcomes of living kidney donation beyond the first year from donation were retrospective. In this prospective study, the outcome of 81 consecutive living kidney donors was thoroughly evaluated. Clinical, laboratory, and radiological assessments were carried out at predonation (basal), 3, 6, 12, and 24 months after donation. The mean age at time of donation was 37.8 ± 9.8 years and the majority was females (75.3%). The mean BMI increased significantly after donation (P < 0.04). The mean serum creatinine levels (mg/dl) were 0.75 ± 0.14, 1.01 ± 0.22, 0.99 ± 0.21, 0.98 ± 0.20, and 0.94 ± 0.20 (P < 0.0001). Likewise, the mean levels of measured creatinine clearance (mL/min) were 148.8 ± 35.7, 94.7 ± 26.6, 95.5 ± 24.6, 96.7 ± 20.2, and 101.6 ± 26.2 (P < 0.0001). The mean 24 hours urinary protein excretion (gm/dL) were 0.09 ± 0.03, 0.19 ± 0.18, 0.16 ± 0.09, 0.18 ± 0.25, and 0.17 ± 0.12 (P < 0.0001). There were significant increases in the means of the longitudinal and transverse diameters of the remaining kidney over time (P < 0.001). Out of 42 female donors, eleven female donors have got successful postdonation pregnancies. There were no reported surgical complications, either intra- or postoperative. Long-term follow-up is necessary for all living kidney donors through local institutional and world registries. This trial is registered with ClinicalTrials.gov NCT00813579.

Shifting paradigms in eligibility criteria for live kidney donation: a systematic review

As the organ shortage increases, inherently the demand for donor kidneys continues to rise. Thus, live kidney donation is essential for increasing the donor pool. In order to create successful expansion, extended criteria live kidney donors should be considered. This review combines current guidelines with all available literature in this field, trying to seek and establish the optimal extended criteria. Comprehensive searches were carried out in major databases until November 2013 to search for articles regarding older age, overweight and obesity, hypertension, vascular anomalies/multiplicity, nulliparous women, and minors as donors. Of the 2079 articles found, 152 fell within the scope of the review. Five major guidelines were included and reviewed. Based on the literature search, live kidney donation in older donors (up to 70 years of age) seems to be safe as outcome is comparable to younger donors. Obese donors have comparable outcome to lean donors, in short- and mid-term follow-up. Since little literature is available proving the safety of donation of hypertensive donors, caution is advised. Vascular multiplicity poses no direct danger to the donor and women of childbearing age can be safely included as donors. Although outcome after donation in minors is shown to be comparable to adult donors, they should only be considered if no other options exist. We conclude that the analyzed factors above should not be considered as absolute contraindications for donation.

The Outcomes of Living Kidney Donation from Medically Complex Donors: Implications for the Donor and the Recipient

Living kidney donation is an important option for patients with end-stage renal disease (ESRD), and has improved life expectancy and quality for patients otherwise requiring maintenance dialysis or deceased-donor transplantation. Given the favorable outcomes of live donation and the shortage of organs to transplant, individuals with potentially unfavorable demographic and clinical characteristics are increasingly being permitted to donate kidneys. While this trend has successfully expanded the live donor pool, it has raised concerns as to which acceptance criteria are safe. This review aims to summarize the existing literature on the outcomes of transplantation from medically complex, living kidney donors, including both donor and recipient outcomes when available.

Effect of A Reduction in glomerular filtration rate after NEphrectomy on arterial STiffness and central hemodynamics: rationale and design of the EARNEST study

Background

There is strong evidence of an association between chronic kidney disease (CKD) and cardiovascular disease. To date, however, proof that a reduction in glomerular filtration rate (GFR) is a causative factor in cardiovascular disease is lacking. Kidney donors comprise a highly screened population without risk factors such as diabetes and inflammation, which invariably confound the association between CKD and cardiovascular disease. There is strong evidence that increased arterial stiffness and left ventricular hypertrophy and fibrosis, rather than atherosclerotic disease, mediate the adverse cardiovascular effects of CKD. The expanding practice of live kidney donation provides a unique opportunity to study the cardiovascular effects of an isolated reduction in GFR in a prospective fashion. At the same time, the proposed study will address ongoing safety concerns that persist because most longitudinal outcome studies have been undertaken at single centers and compared donor cohorts with an inappropriately selected control group.

Hypotheses

The reduction in GFR accompanying uninephrectomy causes (1) a pressure-independent increase in aortic stiffness (aortic pulse wave velocity) and (2) an increase in peripheral and central blood pressure.

Methods

This is a prospective, multicenter, longitudinal, parallel group study of 440 living kidney donors and 440 healthy controls. All controls will be eligible for living kidney donation using current UK transplant criteria. Investigations will be performed at baseline and repeated at 12 months in the first instance. These include measurement of arterial stiffness using applanation tonometry to determine pulse wave velocity and pulse wave analysis, office blood pressure, 24-hour ambulatory blood pressure monitoring, and a series of biomarkers for cardiovascular and bone mineral disease.

Conclusions

These data will prove valuable by characterizing the direction of causality between cardiovascular and renal disease. This should help inform whether targeting reduced GFR alongside more traditional cardiovascular risk factors is warranted. In addition, this study will contribute important safety data on living kidney donors by providing a longitudinal assessment of well-validated surrogate markers of cardiovascular disease, namely, blood pressure and arterial stiffness. If any adverse effects are detected, these may be potentially reversed with the early introduction of targeted therapy. This should ensure that kidney donors do not come to long-term harm and thereby preserve the ongoing expansion of the living donor transplant program (NCT01769924).

Obesity and metabolic syndrome in kidney transplantation

The epidemic of obesity and metabolic syndrome (MS) contributes to the rapid growth of chronic kidney disease (CKD) and end-stage renal disease (ESRD). There is a reverse epidemiology, known as the "obesity paradox," in ESRD patients receiving maintenance dialysis. Obese patients are routinely referred for kidney transplant, and they have more surgical and medical complications than non-obese patients. However, compared to dialysis, kidney transplant provides a survival benefit for obese patients. After kidney transplant, obese patients tend to gain more body weight, and non-obese patients can develop new-onset obesity/MS. Obesity/MS is not only associated with serious morbidities, but also compromises the long-term graft and patient survival. The immunosuppressive drugs commonly used as maintenance therapy, including corticosteroids, calcineurin inhibitors and mammalian target-of-rapamycin inhibitors, contribute to obesity/MS. Development of novel immunosuppressive drugs free of metabolic adverse effects is needed, so that the full potential and benefits of kidney transplantation can be realized.

Obesity as a barrier to living kidney donation: a center-based analysis

BACKGROUND

Obesity is a major epidemic and may present a significant barrier to living kidney donation. The purpose of our study was to determine the frequency of obesity as an exclusion factor and assess how often these donors lose weight and donate.

METHODS

A single center, retrospective analysis of 104 potential living kidney donors between 2008 and 2012.

RESULTS

Of the 104 donors, 19 (18%) had a normal body mass index (BMI) of <25. Eighty-five of the 104 (82%) donors spanned the overweight to morbidly obese classifications. Thirty-eight (37%) were overweight (BMI 25-29.9). Twenty-four (23%) were categorized as class I obesity (BMI 30-34.9), 17 (16%) as class II obesity (BMI 35-39.9), and six (6%) as class III obesity (BMI >40). There were a total of 23 donors (22%) who were considered moderately and morbidly obese (BMI >35). Of these, only three (13%) succeeded at losing weight and donating.

CONCLUSIONS

Obesity may be a frequent barrier to living kidney donation, directly leading to exclusion as a potential kidney donor in about one in five instances. Successful weight loss leading to donation appears to be infrequent, suggesting need to address obesity in the donor population.

Renal function and cardiovascular outcomes after living donor nephrectomy in the UK: quality and safety revisited

OBJECTIVE

To determine renal function and cardiovascular outcomes after living donor nephrectomy (LDN). Living donor kidney transplantation has become established as the treatment of choice for end-stage renal failure. Benefits to the recipient have to be balanced against perioperative and long-term health risks to the donor.

SUBJECTS/PATIENTS AND METHODS

The UK Transplant Registry (UKTR) was used to identify 4586 living donors who had donated a kidney for transplantation in the UK between 2001 and 2008. This study was conducted with the consent and support of the NHS Blood and Transplant (NHSBT) Kidney and Pancreas Research Group.

RESULTS

The mean glomerular filtration rate (GFR) fell from 103 mL/min/1.73 m(2) before LDN to 58 mL/min/1.73 m(2) 1 year after LDN. At 1 year after LDN 60% of donors had a GFR of <60 mL/min/1.73 m(2). A GFR of <60 mL/min/1.73 m(2) after LDN was associated with older age, females, lower GFR before LDN, White ethnicity, earlier LDN period, unrelated donor type and body mass index of >25 kg/m(2). Over a 2-year period after LDN there was an overall mortality rate of 0.39%, cardiovascular death in one patient (mortality rate of 0.02%) and a major cardiovascular event rate of 0.44%.

CONCLUSION

In this study we show that mild renal dysfunction is common after LDN; however, due to the short duration of follow-up we are unable to comment on whether this subsequently leads to an increased risk of developing of cardiovascular disease.

Does a nephron deficit exacerbate the renal and cardiovascular effects of obesity?

It has been hypothesized that a reduced nephron endowment exacerbates the hypertensive and renal effects of obesity. We therefore examined the impact of diet-induced obesity on renal structure and function, and arterial pressure in a genetic model of reduced nephron endowment, the GDNF Heterozygous (HET) mouse. 6wk-old male GDNF WT and HET mice were placed on control or high fat (HFF) diet for 20 weeks. 24 hr arterial pressure, heart rate and activity (radiotelemetry), creatinine clearance and albumin excretion were measured, and kidneys collected (histopathology, collagen content). Bodyweights of HFF WT (50.6±1.2 g) and HET (48.8±1.4 g) mice were ∼14 g greater than control mice (37.3±1.3 g, 36.4±1.1 g respectively; Pdiet<0.001). Obesity led to significantly greater 24 hr MAP (Pdiet<0.001), heart rate (Pdiet<0.01) and lower locomotor activity (Pdiet<0.01) in HET and WT mice. Whilst there was no significant impact of genotype on 24 hr MAP response to obesity, night-time MAP of obese HET mice was significantly greater than obese WT mice (122.3±1.6 vs 116.9±1.3 mmHg; P<0.05). 24 hr creatinine clearance was 50%, and albumin excretion 180% greater in obese WT and HET mice compared to controls (Pdiet<0.05) but this response did not differ between genotypes. Obesity induced glomerulomegaly, glomerulosclerosis, tubulointerstitial expansion and increased collagen accumulation (total, collagen I, V and IV; Pdiet<0.001). Obese GDNF HET mice had exacerbated total renal collagen (P<0.01), and greater levels of the collagen I subtype compared to kidneys of obese WT mice. In summary, obese nephron-deficient GDNF HET mice were able to maintain the high creatinine clearances of obese WT mice but at the expense of higher MAP and greater renal fibrosis. Whilst modest, our findings support the hypothesis that a reduced nephron endowment increases the susceptibility to obesity-induced kidney disease and hypertension.

L-arginine or tempol supplementation improves renal and cardiovascular function in rats with reduced renal mass and chronic high salt intake

AIM

Early life reduction in nephron number and chronic high salt intake cause development of renal and cardiovascular disease, which has been associated with oxidative stress and nitric oxide (NO) deficiency. We investigated the hypothesis that interventions stimulating NO signalling or reducing oxidative stress may restore renal autoregulation, attenuate hypertension and reduce renal and cardiovascular injuries following reduction in renal mass and chronic high salt intake.

METHODS

Male Sprague-Dawley rats were uninephrectomized (UNX) or sham-operated at 3 weeks of age and given either a normal-salt (NS) or high-salt (HS) diet. Effects on renal and cardiovascular functions were assessed in rats supplemented with substrate for NO synthase (L-Arg) or a superoxide dismutase mimetic (Tempol).

RESULTS

Rats with UNX + HS developed hypertension and displayed increased renal NADPH oxidase activity, elevated levels of oxidative stress markers in plasma and urine, and reduced cGMP in plasma. Histological analysis showed signs of cardiac and renal inflammation and fibrosis. These changes were linked with abnormal renal autoregulation, measured as a stronger tubuloglomerular feedback (TGF) response. Simultaneous treatment with L-Arg or Tempol restored cGMP levels in plasma and increased markers of NO signalling in the kidney. This was associated with normalized TGF responses, attenuated hypertension and reduced signs of histopathological changes in the kidney and in the heart.

CONCLUSION

Reduction in nephron number during early life followed by chronic HS intake is associated with oxidative stress, impaired renal autoregulation and development of hypertension. Treatment strategies that increase NO bioavailability, or reduce levels of reactive oxygen species, were proven beneficial in this model of renal and cardiovascular disease.

Systematic review and meta-analysis of the relation between body mass index and short-term donor outcome of laparoscopic donor nephrectomy

In this era of organ donor shortage, live kidney donation has been proven to increase the donor pool; however, it is extremely important to make careful decisions in the selection of possible live donors. A body mass index (BMI) above 35 is generally considered as a relative contraindication for donation. To determine whether this is justified, a systematic review and meta-analysis were carried out to compare perioperative outcome of live donor nephrectomy between donors with high and low BMI. A comprehensive literature search was performed in MEDLINE, Embase, and CENTRAL (the Cochrane Library). All aspects of the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement were followed. Of 14 studies reviewed, eight perioperative donor outcome measures were meta-analyzed, and, of these, five were not different between BMI categories. Three found significant differences in favor of low BMI (29.9 and less) donors with significant mean differences in operation duration (16.9 min (confidence interval (CI) 9.1-24.8)), mean difference in rise in serum creatinine (0.05 mg/dl (CI 0.01-0.09)), and risk ratio for conversion (1.69 (CI 1.12-2.56)). Thus, a high body mass index (BMI) alone is no contraindication for live kidney donation regarding short-term outcome.

Expanded Criteria Living Donors: How Far Can We Go?

In an effort to expand the deceased donor pool, transplant centers have accepted expanded criteria donors as appropriate for many of the patients in the deceased donor pool. Translating this into the living donor pool is more complex. One must consider not only the quality of the organ procured but the consequences that the nephrectomy might have on the living donors for the rest of their lives. This review examines the available data on higher risk donors and the appropriateness, or lack thereof, of accepting them as kidney donors.

Long-term outcomes of kidney donors

PURPOSE OF REVIEW

Living kidney donors face a unique decision of self-sacrifice that is not without potential risk. The purpose of this review is to highlight existing research regarding the perioperative morbidity, mortality and long-term outcomes of living kidney donors.

RECENT FINDINGS

Recent studies of long-term donor survival have affirmed that the life expectancy for living kidney donors is excellent and their risk of end-stage renal disease (ESRD) is not increased. Long-term health outcomes for living donors representing minority groups, however, may not be as favorable. Recent studies conclude that African-American and Hispanic donors, similarly to nondonors of the same race, are at higher risk of developing chronic kidney disease (CKD), hypertension, and diabetes mellitus. Outcomes in medically complex donors have also generated considerable attention, and the evidence on outcomes among otherwise healthy obese and older donors appears to be reassuring.

SUMMARY

Living kidney donation is a superior transplantation option for many individuals with ESRD. The survival and health consequences of living donation have proven to be excellent. These favorable outcomes stem from careful screening measures, and further research endeavors are needed to ensure long-term living donor safety in high-risk donors.

Creatinine-based estimations of kidney function are unreliable in obese kidney donors

Accurate assessment of kidney function by measurement of glomerular filtration rate (GFR) is essential to the risk assessment of prospective living kidney donors. We evaluated the performance of various estimating equations for creatinine clearance (Cockcroft-Gault), GFR (Modification of Diet in Renal Disease, Chronic Kidney Disease Epidemiology Collaboration), and 24-hour urine collections for creatinine clearance in obese potential kidney donors. We evaluated 164 potential kidney donors including 49 with a BMI of 30–35 and 32 with a BMI >35 that have completed a routine living donor evaluation with a measured GFR. All the estimating equations performed poorly in obese donors. While 24-hour urine collections performed better, only 15% had an adequate 24-hour urine collection. Since obese kidney donors may be at higher than average risk for kidney failure, accurate assessment of kidney function in these donors is crucial to ensure their long-term health postdonation.