Insulin Sensitivity After Living Donor Nephrectomy

BACKGROUND

The kidney is essential for glucose and insulin metabolism. Living kidney donors (LKDs) experience a reduction in glomerular filtration rate of 25 to 30 mL/min after donor nephrectomy. Little is known about the effect of glomerular filtration rate decline on insulin sensitivity in LKDs.

METHODS

We conducted a prospective pilot study on 9 LKDs (N = 9) who underwent dynamic metabolic testing (mixed meal tolerance test) to measure proxies of insulin sensitivity (homeostatic model assessment of insulin resistance, the area under curve [AUC] for insulin/glucose ratio, and Matsuda insulin sensitivity index) before and 3 months after donor nephrectomy. The primary outcome was the change in insulin sensitivity indices (delta [post-nephrectomy - pre-nephrectomy]).

RESULTS

Four of the donors had a body mass index (BMI) between 32.0 and 36.7 predonation. Post-donor nephrectomy, compared with prenephrectomy values, median insulin AUC increased from 60.7 to 101.7 hr*mU/mL (delta median 33.3, P = .04) without significant change in median glucose AUC levels from 228.9 to 209.3 hr*mg/dL (delta median 3.2, P = .77). There was an increase in the median homeostatic model assessment of insulin resistance from 2 to 2.9 (delta median 0.8, P = .03) and the AUC insulin/glucose ratio from 30.9 to 62.1 pmol/mmol (delta median 17.5, P = .001), whereas the median Matsuda insulin sensitivity index decreased from 5.9 to 2.9 (delta median -2, P = .05). The changes were more pronounced in obese (BMI >32) donors.

CONCLUSION

LKDs appear to have a trend toward a decline in insulin sensitivity post-donor nephrectomy in the short term, especially in obese donors (BMI >32). Further investigation with a larger sample size and longer follow-up is needed.

Prevalence and risk factors of hypertension following nephrectomy in living kidney donors

Living donor kidney transplantation is the treatment of choice for the patients with end-stage renal disease, especially where deceased donor programs are limited. There are limited data on the outcomes of living kidney donors (LKD) from developing countries, especially from North Africa. The aim of this study is to evaluate the prevalence of hypertension (HTN) in LKD and to analyze its risk factors. This is a longitudinal monocentric study, and the donors who underwent nephrectomy for donation between 2006 and 2015 were included. Ninety-two donors were assessed. The mean age at the time of nephrectomy was 42.8 ± 10 years (21-68 years). The sex ratio was 0.6. At the time of donation, the median systolic blood pressure was 120 mm Hg and the median diastolic blood pressure was 70 mm Hg. HTN was noted in 4% of donors. The median follow-up duration was 26 months. Two years after donation, the prevalence of HTN was 28% in the study group (8% male and 20% female). The mean time to development of HTN was 16 months. Associations between HTN after donation and the cardiovascular family history, age >40 years, HTN, obesity, android obesity, glomerular filtration rate GFR <90 mL/min/1.73 m², perioperative HTN, and dyslipidemia were noted. The multivariate analysis showed that obesity at the time of donation was a risk factor for HTN (odds ratio = 4.8; P = 0.04). Obese donor [body mass index (BMI) ≥30)] has higher risk of HTN after nephrectomy than nonobese donor.

Ethical issues relating to renal transplantation from prediabetic living donor

Background

In Mexico, diabetes mellitus is the main cause of end − stage kidney disease, and some patients may be transplant candidates. Organ supply is limited because of cultural issues. And, there is a lack of standardized clinical guidelines regarding organ donation. These issues highlight the tension surrounding the fact that living donors are being selected despite being prediabetic. This article presents, examines and discusses using the principles of non-maleficience, autonomy, justice and the constitutionally guaranteed right to health, the ethical considerations that arise from considering a prediabetic person as a potential kidney donor.

Discussion

Diabetes is an absolute contraindication for donating a kidney. However, the transplant protocols most frequently used in Mexico do not consider prediabetes as exclusion criteria. In prediabetic persons there are well known metabolic alterations that may compromise the long − term outcomes of the transplant if such donors are accepted. Even so, many of them are finally included because there are not enough donor candidates. Both, families and hospitals face the need to rapidly accept prediabetic donors before the clinical conditions of the recipient and the evolution of the disease exclude him/her as a transplant candidate; however, when using a kidney potentially damaged by prediabetes, neither the donor’s nor the recipient’s long term health is usually considered.

Considering the ethical implication as well as the clinical and epidemiological evidence, we conclude that prediabetic persons are not suitable candidates for kidney donation. This recommendation should be taken into consideration by Mexican health institutions who should rewrite their transplant protocols.

Summary

We argue that the decision to use a kidney from a living donor known to be pre-diabetic or from those persons with family history of T2DM, obesity, hypertension, or renal failure, should be considered unethical in Mexico if the donor bases the decision to donate on socially acceptable norms rather than informed consent as understood in modern medicine.

Nutrition assessment and counseling of the medically complex live kidney donor

Kidney transplantation is the preferred option for patients with end-stage renal disease facing the need for dialysis because it provides maximum survival benefit. The number of people seeking kidney transplantation greatly exceeds available deceased donor organs. Organs from live donors provide a survival advantage over organs from deceased donors while also broadening the pool of available organs. The purpose of this review is to discuss the clinical guidelines that pertain to live kidney organ donation and to describe the nutrition evaluation and care of live kidney donors. The process for living kidney donation is dictated by policies centered on protecting the donor. In a perfect world, the living donor would present with a flawless medical examination and a benign family health history. The obesity epidemic has emerged as a major health concern. Live donor programs are faced with evaluating increasing numbers of obese candidates. These "medically complex donors" may present with obesity and its associated comorbid conditions, including hypertension, impaired glycemic control, and kidney stone disease. The dietitian's role in the live donor program is not well defined. Participation in the living donor selection meeting, where details of the evaluation are summarized, provides a platform for risk stratification and identification of donors who are at increased lifetime risk for poor personal health outcomes. Guiding the donor toward maintenance of a healthy weight through diet and lifestyle choices is a legitimate goal to minimize future health risks.

Renal transplantation from elderly living donors

Acceptance of elderly living kidney donors remains controversial due to the higher incidence of comorbidity and greater risk of postoperative complications. This is a review of publications in the English language between 2000 and 2013 about renal transplantation from elderly living donors to determine trends and effects of donation, and the outcomes of such transplantation. The last decade witnessed a 50% increase in living kidney donor transplants, with a disproportionate increase in donors >60 years. There is no accelerated loss of kidney function following donation, and the incidence of established renal failure (ERF) and hypertension among donors is similar to that of the general population. The overall incidence of ERF in living donors is about 0.134 per 1000 years. Elderly donors require rigorous assessment and should have a predicted glomerular filtration rate of at least 37.5 mL/min/1.73 m(2) at the age of 80. Though elderly donors had lower glomerular filtration rate before donation, proportionate decline after donation was similar in both young and elderly groups. The risks of delayed graft function, acute rejection, and graft failure in transplants from living donors >65 years are significantly higher than transplants from younger donors. A multicentred, long-term, and prospective database addressing the outcomes of kidneys from elderly living donors is recommended.

Living donor practices in the United States

Living kidney donation is a common procedure in the United States. Substantial variation exists between transplant centers in their protocols and exclusion criteria for potential living donors. In the absence of clinical trial data to guide decisions about exclusion criteria, knowledge of current practices is an important first step in guiding the formulation of donor protocols and future studies. Certain trends in living donation practices have become apparent from surveys of transplant programs over the past few decades. Over the past 25 years, opposition to living unrelated donation in the United States has gone from strong to essentially nonexistent. With respect to donor age, programs have become less strict regarding upper age limits but stricter regarding younger donor candidates. Protocols regarding kidney function, blood pressure, and diabetes screening also continue to evolve. Although donor follow-up is mandated by the Organ Procurement and Transplantation Network for 2 years after donation, a majority of donors are lost to follow-up by 1 year. The most commonly cited barriers to donor follow-up include donor inconvenience, cost issues including reimbursement to care providers, and direct and indirect costs to donors. In this article, we review the current knowledge about living donor practices in the United States.

Approach to the pretransplant evaluation of the living kidney donor

Evaluation of the potential kidney donor is a complex activity that differs substantially from other types of preoperative assessments. The well being of the donor, who derives no medical benefit from this surgery, must be assured in both the short term and long term, and the potential adverse consequences to the recipient must be determined as well. The criteria that must be met for a person to donate a kidney are rigorous and include medical, social, psychosocial, ethical, and legal issues. Donor evaluation can be divided into assessments to protect the health and safety of the donor and assessments to protect the health and safety of the recipient. This article provides an approach to evaluating a donor, focusing on the complex issues that an evaluator is faced with. A careful assessment of risks and benefits to both the donor and recipient can lead to favorable outcomes.