Changes in Body Weight Before and After Kidney Donation

Pros and cons of live kidney donation in prediabetics: A critical review and way forward

There is shortage of organs, including kidneys, worldwide. Along with deceased kidney transplantation, there is a significant rise in live kidney donation. The prevalence of prediabetes (PD), including impaired fasting glucose and impaired glucose tolerance, is on the rise across the globe. Transplant teams frequently come across prediabetic kidney donors for evaluation. Prediabetics are at risk of diabetes, chronic kidney disease, cardiovascular events, stroke, neuropathy, retinopathy, dementia, depression and nonalcoholic liver disease along with increased risk of all-cause mortality. Unfortunately, most of the studies done in prediabetic kidney donors are retrospective in nature and have a short follow up period. There is lack of prospective long-term studies to know about the real risk of complications after donation. Furthermore, there are variations in recommendations from various guidelines across the globe for donations in prediabetics, leading to more confusion among clinicians. This increases the responsibility of transplant teams to take appropriate decisions in the best interest of both donors and recipients. This review focuses on pathophysiological changes of PD in kidneys, potential complications of PD, other risk factors for development of type 2 diabetes, a review of guidelines for kidney donation, the potential role of diabetes risk score and calculator in kidney donors and the way forward for the evaluation and selection of prediabetic 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.

Weight trends in living kidney donors suggest predonation counselling alone lacks a sustainable effect on weight loss: a single centre cohort study

Living kidney donors are at risk of long-term end-stage renal disease, and obesity is an independent risk factor. In our centre, predonation counselling of obese donors concentrates on lifestyle modifications, particularly weight loss and exercise. Whether these recommendations have a sustainable effect after donation remains unknown. We conducted a retrospective analysis of all donors who proceeded to donation between 2012 and 2016. Donors' body mass index (BMI) was compared between predefined time points using matched pair analysis. Among 303 donors included, 15% were obese at initial assessment. Obese donors were observed to lose weight by the time of donation (mean BMI difference 1.32 kg/m² , P < 0.001), but bounced back to their initial weight at one-year postdonation (mean BMI difference + 1.47 kg/m² , P < 0.001), which was maintained at two-year postdonation. While 71% of obese donors lost weight by the time of donation, 56% of them gained that weight back at one year. Our findings underline the success of predonation counselling on lifestyle modification in highly motivated obese donors, although additional strategies are required to sustain weight loss. The impact of weight gain on long-term risk needs further evaluation. Living donor programmes should provide continued support with lifestyle modifications after donation.

Metabolic, cardiovascular, and substance use evaluation of living kidney donor candidates: US practices in 2017

We surveyed US transplant centers to assess practices regarding the evaluation and selection of living kidney donors based on metabolic, cardiovascular, and substance use risk factors. Our companion article describes renal aspects of the evaluation. Response rate was 31%. Compared with 2005, programs have become more accepting of hypertensive candidates: 65% in 2017% vs 41% in 2005 consider candidates with hypertension well controlled with 1 medication. One notable exception is black hypertensive candidates, who are frequently excluded regardless of severity. The most common body mass index (BMI) cutoff remains 35 kg/m² , and fewer programs now consider candidates with BMI >40 kg/m² . A 2-hour oral glucose tolerance test of ≥140 mg/dL remains the most common criterion for exclusion of prediabetic candidates. One quarter to one third of programs exclude based on isolated cardiac abnormalities, such as mild aortic stenosis; a similar proportion consider these candidates only if older than 50 years. Cigarette or marijuana smoking are infrequently criteria for exclusion, although 45% and 37% programs, respectively, require cessation 4 weeks prior to surgery. In addition to providing an overview of current practices in living kidney donor evaluation, our study highlights the importance of research evaluating outcomes with various comorbidities to guide practice.

The need for a living donor wellness program

PURPOSE OF REVIEW

Living donation has a tremendous impact in bridging the gap between the shortage of organs and the growing list of transplant candidates but remains underutilized as a percentage of total transplants performed. This review focuses on obesity and social determinants of health as potential barriers to the expansion of living kidney donation.

RECENT FINDINGS

The growing rate of obesity and associated metabolic syndrome make many potential donors unacceptable as donor candidates because of the future risk for developing chronic health conditions, such as hypertension and diabetes. There is also increasing evidence demonstrating socioeconomic differences and racial disparities potentially limit access to living donation in certain populations. These potentially modifiable factors are not exclusive of each other and together serve as significant contributing factors to lower rates of living donation.

SUMMARY

Living donors make sacrifices to provide the gift of life to transplant recipients, despite the potential risks to their own health. Studies describing risk factors to living donation call attention to the overall need for more action to prioritize and promote the health and well being of living donors.