The survival benefit of kidney transplantation in obese patients

Kidney Transplant Candidacy: Addressing Common Medical and Psychosocial Barriers to Transplant

Improving access to kidney transplants remains a priority for the transplant community. However, many medical, psychosocial, geographic, and socioeconomic barriers exist that prevent or delay transplantation for candidates with certain conditions. There is a lack of consensus regarding how to best approach many of these issues and barriers, leading to heterogeneity in transplant centers' management and acceptance practices for a variety of pretransplant candidate issues. In this review, we address several of the more common contemporary patient medical and psychosocial barriers frequently encountered by transplant programs. The barriers discussed here include kidney transplant candidates with obesity, older age, prior malignancy, cardiovascular disease, history of nonadherence, and cannabis use. Improving understanding of how to best address these specific issues can empower referring providers, transplant programs, and patients to address these issues as necessary to progress toward eventual successful transplantation.

Exploring the nexus: The place of kidney diseases within the cardiovascular-kidney-metabolic syndrome spectrum

Cardiovascular-kidney-metabolic (CKM) syndrome and chronic kidney disease (CKD) are two significant comorbidities affecting a large proportion of the general population with considerable crosstalk. In addition to substantial co-incidence of CKD and CKM syndrome in epidemiological studies, clinical and pre-clinical studies have identified similar pathophysiological pathways leading to both entities. Patients with CKM syndrome are more prone to develop acute kidney injury and CKD, while therapeutic alternatives and their success rates are considerably lower in such patient groups. Nevertheless, the association between CKM syndrome and CKD or ESKD is bidirectional rather than being a cause-effect relationship as patients with CKD are also prone to develop peripheral insulin resistance, high blood pressure, and dyslipidemia. Furthermore, such patients are less likely to receive kidney transplantation in addition to the higher allograft dysfunction risk. We hereby aim to evaluate the association in-between kidney diseases and CKM syndrome, including epidemiological data, pre-clinical studies with pathophysiological pathways, and potential therapeutic perspectives.

Obesity-associated Inflammation and Alloimmunity

Obesity is a worldwide health problem with a rapidly rising incidence. In organ transplantation, increasing numbers of patients with obesity accumulate on waiting lists and undergo surgery. Obesity is in general conceptualized as a chronic inflammatory disease, potentially impacting alloimmune response and graft function. Here, we summarize our current understanding of cellular and molecular mechanisms that control obesity-associated adipose tissue inflammation and provide insights into mechanisms affecting transplant outcomes, emphasizing on the beneficial effects of weight loss on alloimmune responses.

Economic evaluation of weight loss and transplantation strategies for kidney transplant candidates with obesity

Novel antiobesity medications, particularly glucagon-like peptide-1 receptor agonists (GLP-1RAs), have expanded weight loss (WL) options for kidney transplantation (KT) candidates with obesity beyond lifestyle modifications and bariatric surgery. However, varying effectiveness, risk profiles, and costs make strategy choices challenging. To aid decision-making, we used a Markov model to examine the cost-effectiveness of different WL strategies over a 10-year horizon. A target WL of 15% of total body weight was used for the base case scenario, and we compared these strategies to a "liberal" KT strategy of transplanting candidates with obesity. Outcomes included costs (2023 US dollars), quality-adjusted life years, and incremental cost-effectiveness ratios. In analysis, a liberal KT strategy was favored over lifestyle modifications and GLP-1RAs. Among WL strategies, bariatric surgery was the most effective and cost the least, whereas lifestyle modification had the highest cumulative costs and was the least effective. Compared to liberal KT, bariatric surgery costs $45 859 per quality-adjusted life year gained. GLP-1RAs were favored over bariatric surgery only when drug costs were below $5000 per year (base cost $12 077). In conclusion, for KT candidates with obesity, a liberal KT strategy and bariatric surgery are preferred over lifestyle modifications alone and GLP-1RAs based on outcomes and cost-effectiveness.

Treatment of Type 2 Diabetes Mellitus in Advanced Chronic Kidney Disease for the Primary Care Physician

Diabetes mellitus (DM) is a common cause of chronic kidney disease (CKD), leading to the need for renal replacement therapy (RRT). RRT includes hemodialysis (HD), peritoneal dialysis (PD), kidney transplantation (KT), and medical management. As CKD advances, the management of DM may change as medication clearance, effectiveness, and side effects can be altered due to decreasing renal clearance. Medications like metformin that were safe to use early in CKD may build up toxic levels of metabolites in advanced CKD. Other medications, like sodium-glucose co-transporter 2 inhibitors, which work by excreting glucose in the urine, may not be able to work effectively in advanced CKD due to fewer working nephrons. Insulin breakdown may take longer, and both formulation and dosing may need to be changed to avoid hypoglycemia. While DM control contributes to CKD progression, effective DM control continues to be important even after patients have been placed on RRT. Patients on RRT are frequently taken care of by a team of providers, including the primary care physician, both in and outside the hospital. Non-nephrologists who are involved with the care of a patient treated with RRT need to be adept at managing DM in this population. This paper aims to outline the management of type 2 DM in advanced CKD.

Approach to weight management in patients with advanced chronic kidney disease in a real-life clinical setting

Objective

Excess adiposity represents a risk factor for chronic kidney disease (CKD) and progression to end-stage kidney disease. Anti-Obesity Medications (AOMs) are vastly underutilized in patients with advanced CKD because of concerns related to safety and efficacy. This study was conducted to evaluate the real-world approach to weight management and the efficacy and safety of AOMs in people with advanced CKD.

Methods

This is a retrospective analysis of individuals with Body Mass Index (BMI) ≥ 27 kg/m2 and eGFR ≤ 30 mL/min/1.73 m2 referred to an academic medical weight-management program between 01/2015 and 09/2022. Evaluation of weight-management approaches, body weight change, treatment-related side effects, and reasons for treatment discontinuation were reported.

Results

Eighty-nine patients met inclusion criteria, 16 were treated with intensive lifestyle modifications (ILM) alone and 73 with AOMs (all treated with glucagon-like peptide-1 receptor agonist [GLP1-RA] +/- other AOMs) along with ILM. Patients treated with AOMs had a longer duration of on-treatment follow-up (median 924 days) compared to (93 days) the ILM group. Over 75% of patients treated with AOMs lost ≥5% body weight versus 25% of those treated with ILM. Only 15% of patients treated with AOMs discontinued therapy due to treatment-related side effects.

Conclusion

In patients with obesity and advanced CKD, GLP-1RA-based anti-obesity treatment was well-tolerated, effective, and led to durable weight reduction.

Surgical Complications Following Renal Transplantation in a Large Institutional Cohort

Background

Successful renal transplantation (RTx) relies on immunosuppression and an optimal surgical course with few surgical complications. Studies reporting the postoperative complications after RTx are heterogeneous and often lack systematic reporting of complications. This study aims to describe and identify postoperative short-term and long-term complications after RTx in a large institutional cohort and identify risk factors for a complicated surgical course.

Methods

The study is a retrospective single-center cohort of 571 recipients who underwent living or deceased donor open RTx between 2014 and 2021. Data were collected on background information and perioperative and postoperative data. Complications were defined as short-term (<30 d) or long-term (>30 d) after transplantation and graded according to the Clavien-Dindo classification. Multivariable logistic regression was performed to evaluate risk factors for serious short-term complications and multivariable time-dependent Cox regression to evaluate risk factors for long-term complications.

Results

A total of 351 patients received a graft from a deceased donor, and 144 of these grafts were on perfusion machine before transplantation. One or more short-term complications occurred in 345 (60%) patients. Previous RTx was associated with short-term Clavien-Dindo >2 complications in recipients (odds ratio = 2.08; 95% confidence interval [CI], 1.18-3.69; P = 0.01). Being underweight (body mass index <18.5) in combination with increasing age increased the odds of short-term Clavien-Dindo >2 and vascular complications. Increasing blood loss per 100 mL was associated with increased odds of short-term Clavien-Dindo >2 (odds ratio = 1.11; 95% CI, 1.01-1.21; P = 0.032). No associations were found for long-term complications after RTx. The 5-y cumulative incidence of graft loss was 12.6% (95% CI, 8.9-16.3).

Conclusions

Short-term complications are common after RTx, and risk factors for severe short-term complications include previous RTx, increasing age, and low body mass index. No risk factors were identified for severe long-term complications. Further studies should explore whether new surgical techniques can reduce surgical complications in RTx.

Evaluating site-of-care-related racial disparities in kidney graft failure using a novel federated learning framework

OBJECTIVES

Racial disparities in kidney transplant access and posttransplant outcomes exist between non-Hispanic Black (NHB) and non-Hispanic White (NHW) patients in the United States, with the site of care being a key contributor. Using multi-site data to examine the effect of site of care on racial disparities, the key challenge is the dilemma in sharing patient-level data due to regulations for protecting patients' privacy.

MATERIALS AND METHODS

We developed a federated learning framework, named dGEM-disparity (decentralized algorithm for Generalized linear mixed Effect Model for disparity quantification). Consisting of 2 modules, dGEM-disparity first provides accurately estimated common effects and calibrated hospital-specific effects by requiring only aggregated data from each center and then adopts a counterfactual modeling approach to assess whether the graft failure rates differ if NHB patients had been admitted at transplant centers in the same distribution as NHW patients were admitted.

RESULTS

Utilizing United States Renal Data System data from 39 043 adult patients across 73 transplant centers over 10 years, we found that if NHB patients had followed the distribution of NHW patients in admissions, there would be 38 fewer deaths or graft failures per 10 000 NHB patients (95% CI, 35-40) within 1 year of receiving a kidney transplant on average.

DISCUSSION

The proposed framework facilitates efficient collaborations in clinical research networks. Additionally, the framework, by using counterfactual modeling to calculate the event rate, allows us to investigate contributions to racial disparities that may occur at the level of site of care.

CONCLUSIONS

Our framework is broadly applicable to other decentralized datasets and disparities research related to differential access to care. Ultimately, our proposed framework will advance equity in human health by identifying and addressing hospital-level racial disparities.

Engineering Equity Into the Promise of Xenotransplantation

Two of the greatest challenges facing kidney transplantation are the lack of donated organs and inequities in who receives a transplant. Xenotransplantation holds promise as a treatment approach that could solve the supply problem. Major advances in gene-editing procedures have enabled several companies to raise genetically engineered pigs for organ donation. These porcine organs lack antigens and have other modifications that should reduce the probability of immunological rejection when transplanted into humans. The US Food and Drug Administration and transplantation leaders are starting to chart a path to test xenotransplants in clinical trials and later integrate them into routine clinical care. Here we provide a framework that industry, regulatory authorities, payers, transplantation professionals, and patient groups can implement to promote equity during every stage in this process. We also call for immediate action. Companies developing xenotransplant technology should assemble patient advocacy boards to bring the concerns of individuals with end-stage kidney disease to the forefront. For trials, xenotransplantation companies should partner with transplant programs with substantial patient populations of racial and ethnic minority groups and that have reciprocal relationships with those communities. Those companies and transplant programs should reach out now to those communities to inform them about xenotransplantation and try to address their concerns. These actions have the potential to make these communities full partners in the promise of xenotransplantation.

Does obesity really affect renal transplantation outcomes?

INTRODUCTION

Kidney transplantation is the treatment of choice for patients with stage 5 chronic kidney disease (CKD). About 60% of CKD patients are overweight or obese at the time of kidney transplantation, and post-transplant obesity occurs in 50% of patients, with a weight gain of 10% in the first year and high risk of cardiovascular mortality. Obesity is associated with an increased risk of delayed graft function (DGF), acute rejection, surgical complications, graft loss and mortality. The aim of this study is to assess the clinical evolution of obese and overweight patients that have received a kidney transplant, based on short- and long-term complications associated with a higher BMI.

MATERIAL AND METHODS

A descriptive, observational, cross-sectional study was conducted with 104 kidney or pancreas-kidney transplant patients between March 2017 and December 2020, with a follow-up until April 2021. For comparative analysis, patients were grouped according to BMI.

RESULTS

Mean age was of 56.65 years, 60.6% male and 39.4 % female. Overweight patients experienced prolonged surgeries, more surgical wound dehiscence, delayed graft function, hernias, proteinuria and more indications for renal biopsies. Additionally, obese patients displayed more DGF, indications for renal biopsies, proteinuria, development of diabetes mellitus, atrial fibrillation and needed prolonged hospital stays.

CONCLUSIONS

Despite a high prevalence of comorbidity in the overweight and/or obese population, we found no reduction in patient and/or graft survival. However, longer follow-up is needed.

Bariatric Surgery as a Bridge to Facilitate Renal Transplantation in Patients with End-Stage Renal Disease

PURPOSE

Renal transplantation (RT) is not recommended above BMI 40 kg/m2 as post-operative risks (delayed graft function, wound complications) are increased. Bariatric surgery (BS) results in sustained long-term weight loss. However, renal failure (RF) patients are theoretically higher risk candidates. We aim to investigate the safety of BS in patients with RF and the effect of BS on access to renal transplantation.

METHODS

We reviewed data from 31 patients with RF referred for BS between 2013 and 2021. We compared the outcomes of patients with RF who underwent BS to those who were referred but did not undergo BS. Controls matched for age/BMI/comorbidity (MC) but without RF were used for comparison.

RESULTS

Of 31 patients referred, 19 proceeded with BS (68% female, median age 52 years, BMI 46.2 ± 4.9 kg/m2) and 12 did not (58% female, median age 58, mean BMI 41.5 ± 4.1). Excess body weight loss (EBWL) was 71.2% ± 20.2% at 2 years in RF patients versus 66.0% ± 28.0% in MC patients. In the operated group, 11/19 (58%) patients reached their treatment target (six transplanted, five placed on waiting list) versus 3/12 (25%) in unoperated patients (three transplanted). There was no difference in perioperative complications between RF and MC groups. Long-term, there were seven deaths amongst RF patients (two operated, five unoperated), none amongst the MC group.

CONCLUSION

BS in patients with RF increased access to RT and was safe and effective. We therefore recommend consideration of BS in patients with obesity and RF in specialised units.

Obesity in Renal Transplantation

Obesity has surged as a formidable global public health concern, with its prevalence nearly tripling over the past 40 years. Concurrently, the burden of kidney disease remains substantial, with obesity emerging as a significant risk factor. Transplantation is a life-saving intervention for patients with end-stage kidney disease living with obesity. However, it introduces a dual-edged sword, decreasing the risk of mortality related to dialysis while still leaving cardiovascular disease as one of the leading causes of death in transplant recipients. The relationship between obesity and transplantation is a multifaceted challenge demanding concerted efforts from health-care providers, researchers, and policymakers to navigate. While transplantation offers hope and improved quality of life for many, the weight of obesity cannot be underestimated. This review provides a comprehensive assessment of the intricate interplay between obesity and transplantation, with a particular focus on kidney transplantation. Through this review article, we want to reiterate the critical role of weight management, lifestyle modifications, and medical interventions in optimizing transplantation outcomes for individuals with obesity. By comprehensively addressing these issues, we aim to contribute to the development of a holistic approach that minimizes the risks while maximizing the benefits of transplantation for this vulnerable population.

Impact of Obesity on Kidney Transplant Outcomes in Older Adults

BACKGROUND

The prevalence of obesity in older patients undergoing kidney transplantation is increasing. Older age and obesity are associated with higher risks of complications and mortality post-transplantation. The optimal management of this group of patients remains undefined.

METHODS

We retrospectively analyzed the United Network for Organ Sharing database of adults ≥70 years of age undergoing primary kidney transplant from January 1, 2014, to December 31, 2022. We examined patient and graft survival stratified by body mass index (BMI) in 3 categories, <30 kg/m2, 30 to 35 kg/m2, and >35 kg/m2. We also analyzed other risk factors that impacted survival.

RESULTS

A total of 14,786 patients ≥70 years underwent kidney transplantation. Of those, 9,731 patients had a BMI <30 kg/m2, 3,726 patients with a BMI of 30 to 35 kg/m2, and 1,036 patients with a BMI >35 kg/m2. During the study period, there was a significant increase in kidney transplants in patients ≥70 years old across all BMI groups. Overall, patient survival, death-censored graft survival, and all-cause graft survival were lower in obese patients compared with nonobese patients. Multivariable analysis showed worse patient survival and graft survival in patients with a BMI of 30 to 35 kg/m2, a BMI >35 kg/m2, a longer duration of dialysis, diabetes mellitus, and poor functional status.

CONCLUSION

Adults ≥70 years should be considered for kidney transplantation. Obesity with a BMI of 30 to 35 kg/m2 or >35 kg/m2, longer duration of dialysis, diabetes, and functional status are associated with worse outcomes. Optimization of these risk factors is essential when considering these patients for transplantation.

Surgical complications and graft survival in kidney transplant recipients according to CT-scans evaluation

INTRODUCTION

Obesity is a risk factor for significant surgical complications following kidney transplantation. We examined morphometric parameters other than the body mass index (BMI) that could predict surgical complications and determine their impact on graft survival.

MATERIALS

Kidney transplantations performed at our center between 2012 and 2019 were retrospectively evaluated. Data for visceral adipose tissue (VAT), subcutaneous adipose tissue, psoas surface, abdominal perimeter (AP), and vessel-to-skin distance (VSK) were collected from pre-transplant computed tomography (CT) scans. The primary outcome was the occurrence of surgical complications within 1 year of transplantation; the secondary outcome was graft survival.

RESULTS

We included 321 (88%) of 364 kidney transplant recipients, of which 154 (46.5%) patients experienced some form of surgical complication in the 1st year of follow-up. Univariate analysis revealed that higher VAT (P=0.004), VSK (P=0.007), and AP (P=0.01) values were potential risk factors for early postoperative morbidity. However, none of these factors were significant in the multivariate analysis. Concerning the secondary outcome, while the univariate analysis identified higher VAT (P=0.001) value as a risk factor, in the multivariate analysis only delayed graft function demonstrated a significant impact on graft survival (P=0.002).

CONCLUSIONS

Although morphological parameters showed greater accuracy in predicting surgical complications in univariate analysis, these results were not significant in multivariate analysis. Moreover, these factors were not significantly associated with graft survival. Therefore, routine application of analyses based on these parameters, regardless of BMI, may not be useful.

LEVEL OF EVIDENCE: 5

Effect of Recipient Body Mass Index on Kidney Transplantation Outcomes: A Systematic Review and Meta-analysis by the Transplant Committee from the French Association of Urology

CONTEXT

The impact of recipient obesity on kidney transplantation (KT) outcomes remains unclear.

OBJECTIVE

The aim of this study was to perform a systematic review and meta-analysis to appraise all available evidence on the outcomes of KT in obese patients (body mass index [BMI] ≥30 kg/m2) versus nonobese patients (BMI <30 kg/m2).

EVIDENCE ACQUISITION

A systematic review and meta-analysis was performed. Search was conducted in the MEDLINE OvidSP, Web of Science, Google Scholar, Embase, and Cochrane databases to identify all studies reporting the outcomes of KT in obese versus nonobese recipients.

EVIDENCE SYNTHESIS

Fifty-two articles met the inclusion criteria. Delayed graft function and surgical complications were significantly higher in obese recipients (delayed graft function: relative risk [RR]: 1.44, 95% confidence interval [CI]: 1.32-1.57, p < 0.01; surgical complications: RR: 1.74, 95% CI: 1.36-2.22, p < 0.0001). Five-year patient survival (RR: 0.96, 95% CI: 0.92-1.00, p = 0.01), 10-yr patient survival (RR: 0.90, 95% CI: 0.84-0.97, p = 0.006), and 10-yr graft survival (RR: 0.87, 95% CI: 0.79-0.96, p = 0.01) were significantly inferior in the obese group.

CONCLUSIONS

KT in obese recipients was associated with lower patient and graft survival, and higher delayed graft function, acute rejection, and medical and surgical complications than nonobese recipients. In the current situation of organ shortage and increasing prevalence of obesity, ways to optimize KT in this setting should be investigated.

PATIENT SUMMARY

Compared with nonobese population, kidney transplantation in obese recipients has inferior patient and graft survival, and higher medical and surgical complications.

Review of prognostic factors for kidney transplant survival

Transplantation is the most effective treatment for end-stage chronic kidney disease, as this procedure prolongs and improves the patient's quality of life. One of the key problems is the risk of graft rejection. The purpose of this research was to identify and analyse prognostic factors that will prevent rejection. In particular, the prognostic factors grouped by methods of synthesis, generalisation and statistical processing with calculation and graphical representation of hazard ratio and correlation coefficient were grouped, namely: age of donor and recipient, time of cold kidney ischaemia, duration of preoperative dialysis, body mass index, presence of concomitant diseases (diabetes mellitus, hypertension), primary causes causing transplantation. Several molecular genetic and biochemical prognostic markers (transcription factors, immunocompetent cell signalling and receptors, cytostatin C, creatinine, citrate, lactate, etc.) are annotated. It has been demonstrated that creatinine reduction rate determines the risk of rejection, displaying the dynamics of cystatin C and creatinine changes in the postoperative period. Young recipients who underwent prolonged preoperative dialysis were identified as having the highest risk of rejection. Diabetes and hypertension bear a non-critical but commensurately equal risk of rejection. The survival rate of the graft is better when transplanted from a living donor than from a deceased donor. A correlation between cold ischaemia time, body mass index and the probability of graft failure has been proven, namely, the greater the donor and recipient body mass index and the longer the cold ischaemia time, the lower the chance of successful long-term organ acclimation. The data obtained can be used as prognostic factors for graft accommodation at different intervals after surgery.

When There is No Guidance From the Guidelines: Renal Transplantation in Recipients With Class III Obesity

Whilst renal transplantation is the optimal treatment for many patients with end-stage kidney disease, the latest international guidelines are unable to make recommendations for the management of patients with end-stage kidney stage kidney disease and Class III Obesity (BMI ≥40 kg/m2). Data on all adult patients receiving a kidney-only-transplant in the UK between 2015-2021 were analysed from a prospectively collected database and interrogated across a range of parameters. We then analysed in detail the outcomes of patients transplanted at the highest-volume unit. There were 22,845 renal transplants in the study time-period; just 44 (0.2%) were performed in recipients with a BMI ≥40 kg/m2. Most transplant centres did not transplant any patients in this category. In the centre with the highest volume, there were 21 transplants (9 living donor) performed in 20 individuals (13 male, median age 46 years). One-year patient and death-censored graft survival was 95% and 85%. Successful transplantation is possible in patients with BMI ≥40 kg/m2 but carries additional risk. Obesity should not be the sole factor considered when deciding on transplant suitability. Restricting transplantation to a small number of high-volume centres in each country should be considered to optimize outcomes.

Obesity and Kidney Transplantation-How to Evaluate, What to Do, and Outcomes

Obesity is a growing issue that is spreading worldwide; its prevalence is ever increasing in patients with end-stage renal disease and represents a potential barrier to transplantation. The lack of unanimous guidelines exacerbates the current disparity in treatment, which can affect outcomes, leading to a significantly longer time on the waiting list. Multidisciplinary and multimodal management (encompassing several healthcare professionals such as nephrologists, transplant physicians and surgeons, primary care providers, and nurses) is of paramount importance for the optimal management of this patient population in a continuum from waitlisting to transplantation. Development of this guideline followed a standardized protocol for evidence review. In this review, we report on our clinical experience in transplantation of obese patients; strategies to manage this condition, including bariatric surgery, suitable timing for transplantation among this patient population, and clinical experience in robotic sleeve gastrectomy; and simultaneous robotic kidney transplantation to achieve optimal outcomes.

Comparable kidney transplant outcomes in selected patients with a body mass index ≥ 40: A personalized medicine approach to recipient selection

INTRODUCTION

Many kidney transplant (KT) centers decline patients with a body mass index (BMI) ≥40 kg/m2 . This study's aim was to evaluate KT outcomes according to recipient BMI.

METHODS

We performed a single-center, retrospective review of adult KTs comparing BMI ≥40 patients (n = 84, BMI = 42 ± 2 kg/m2 ) to a matched BMI < 40 cohort (n = 84, BMI = 28 ± 5 kg/m2 ). Patients were matched for age, gender, race, diabetes, and donor type.

RESULTS

BMI ≥40 patients were on dialysis longer (5.2 ± 3.2 years vs. 4.1 ± 3.5 years, p = .03) and received lower kidney donor profile index (KDPI) kidneys (40 ± 25% vs. 53 ± 26%, p = .003). There were no significant differences in prevalence of delayed graft function, reoperations, readmissions, wound complications, patient survival, or renal function at 1 year. Long-term graft survival was higher for BMI ≥40 patients, including after adjusting for KDPI (BMI ≥40: aHR = 1.79, 95% CI = 1.09-2.9). BMI ≥40 patients had similar BMI change in the first year post-transplant (delta BMI: BMI ≥ 40 +.9 ± 3.3 vs. BMI < 40 +1.1 ± 3.2, p = .59).

CONCLUSIONS

Overall outcomes after KT were comparable in BMI ≥40 patients compared to a matched cohort with lower BMI with improved long-term graft survival in obese patients. BMI-based exclusion criteria for KT should be reexamined in favor of a more individualized approach.

Obesity is Associated With Delayed Graft Function in Kidney Transplant Recipients: A Paired Kidney Analysis

Obesity is increasingly prevalent among candidates for kidney transplantation. Existing studies have shown conflicting post-transplant outcomes for obese patients which may relate to confounding bias from donor-related characteristics that were unaccounted for. We used ANZDATA Registry data to compare graft and patient survival between obese (BMI >27.5 kg/m2 Asians; >30 kg/m2 non-Asians) and non-obese kidney transplant recipients, while controlling for donor characteristics by comparing recipients of paired kidneys. We selected transplant pairs (2000-2020) where a deceased donor supplied one kidney to an obese candidate and the other to a non-obese candidate. We compared the incidence of delayed graft function (DGF), graft failure and death by multivariable models. We identified 1,522 pairs. Obesity was associated with an increased risk of DGF (aRR = 1.26, 95% CI 1.11-1.44, p < 0.001). Obese recipients were more likely to experience death-censored graft failure (aHR = 1.25, 95% CI 1.05-1.49, p = 0.012), and more likely to die with function (aHR = 1.32, 95% CI 1.15-1.56, p = 0.001), versus non-obese recipients. Long-term patient survival was significantly worse in obese patients with 10- and 15-year survival of 71% and 56% compared to 77% and 63% in non-obese patients. Addressing obesity is an unmet clinical need in kidney transplantation.

Post-kidney transplant body mass index trajectories are associated with graft loss and mortality

BACKGROUND

Early post-kidney transplantation (KT) changes in physiology, medications, and health stressors likely impact body mass index (BMI) and likely impact all-cause graft loss and mortality.

METHODS

We estimated 5-year post-KT (n = 151 170; SRTR) BMI trajectories using an adjusted mixed effects model. We estimated long-term mortality and graft loss risks by 1-year BMI change quartile (decrease [1st quartile]: change < -.07 kg/m2 /month; stable [2nd quartile]: -.07 ≤ change ≤ .09 kg/m2 /month; increase [3rd, 4th quartile]: change > .09 kg/m2 /month) using adjusted Cox proportional hazards models.

RESULTS

BMI increased in the 3 years post-KT (.64 kg/m2 /year, 95% CI: .63, .64) and decreased in years 3-5 (-.24 kg/m2 /year, 95% CI: -.26, -.22). 1-year post-KT BMI decrease was associated with elevated risks of all-cause mortality (aHR = 1.13, 95% CI: 1.10-1.16), all-cause graft loss (aHR = 1.13, 95% CI: 1.10-1.15), death-censored graft loss (aHR = 1.15, 95% CI: 1.11-1.19), and mortality with functioning graft (aHR = 1.11, 95% CI: 1.08-1.14). Among recipients with obesity (pre-KT BMI≥30 kg/m2 ), BMI increase was associated with higher all-cause mortality (aHR = 1.09, 95% CI: 1.05-1.14), all-cause graft loss (aHR = 1.05, 95% CI: 1.01-1.09), and mortality with functioning graft (aHR = 1.10, 95% CI: 1.05-1.15) risks, but not death-censored graft loss risks, relative to stable weight. Among individuals without obesity, BMI increase was associated with lower all-cause graft loss (aHR = .97, 95% CI: .95-.99) and death-censored graft loss (aHR = .93, 95% CI: .90-.96) risks, but not all-cause mortality or mortality with functioning graft risks.

CONCLUSIONS

BMI increases in the 3 years post-KT, then decreases in years 3-5. BMI loss in all adult KT recipients and BMI gain in those with obesity should be carefully monitored post-KT.

Obesity and kidney transplantation

PURPOSE OF REVIEW

Obesity has reached epidemic proportions in the United States. It is a risk factor for developing, among others, heart disease, stroke, type 2 diabetes, and chronic kidney disease (CKD), and thus a major public health concern and driver of healthcare costs. Although the prevalence of obesity in the CKD/end-stage kidney disease population is increasing, many obese patients are excluded from the benefit of kidney transplant based on their BMI alone. For this reason, we sought to review the experience thus far with kidney transplantation in obese patients and associated outcomes.

RECENT FINDINGS

Obesity is associated with a lower rate of referral and waitlisting, and lower likelihood of kidney transplantation. Despite increased risk for early surgical complications and delayed graft function, experience from multiple centers demonstrate a clear survival benefit of transplantation over dialysis in most obese patients, and comparable graft and patient survival rates to nonobese recipients.

SUMMARY

Data suggest that long-term transplant outcomes among obese recipients are similar to those among nonobese. Strategies to achieve pretransplant weight reduction and minimally invasive surgical techniques may further improve results of kidney transplantation in obese recipients.

The Fat Kidney

PURPOSE OF REVIEW

The purpose of this review is to summarize the current evidence on the role of obesity in the development and progression of chronic kidney disease and the current evidence on nutritional, pharmacological, and surgical strategies for the management of individuals with obesity and chronic kidney disease.

RECENT FINDINGS

Obesity can hurt the kidney via direct pathways, through the production of pro-inflammatory adipocytokines, and indirectly due to systemic complications of obesity, including type 2 diabetes mellitus and hypertension. In particular, obesity can damage the kidney through alterations in renal hemodynamics resulting in glomerular hyperfiltration, proteinuria and, finally, impairment in glomerular filtratation rate. Several strategies are available for weight loss and maintenance, such as the modification of lifestyle (diet and physical activity), anti-obesity drugs, and surgery therapy, but there are no clinical practice guidelines to manage subjects with obesity and chronic kidney disease. Obesity is an independent risk factor for the progression of chronic kidney disease. In subjects with obesity, weight loss can slow down the progression of renal failure with a significant reduction in proteinuria and improvement in glomerular filtratation rate. Specifically, in the management of subjects with obesity and chronic renal disease, it has been shown that bariatric surgery can prevent the decline in renal function, while further clinical studies are needed to evaluate the efficacy and safety on the kidney of weight reducing agents and the very low-calorie ketogenic diet.

The Importance Of Avoiding Time-Dependent Bias When Testing The Prognostic Value Of An Intervening Event - Two Acute Cellular Rejection Examples In Intestinal Transplantation

In testing the prognostic value of the occurrence of an intervening event (clinical event that occurs post-transplant), 3 proper statistical methodologies for testing its prognostic value exist (time dependent covariate, landmark, and semi-Markov modelling methods). However, time-dependent bias has appeared in many clinical reports, whereby the intervening event is statistically treated as a baseline variable (as if it occurred at transplant). Using a single-center cohort of 445 intestinal transplant cases to test the prognostic value of 1^st acute cellular rejection (ACR) and severe (grade of) ACR on the hazard rate of developing graft loss, we demonstrate how the inclusion of such time-dependent bias can lead to severe underestimation of the true hazard ratio (HR). The (statistically more powerful) time dependent covariate method in Cox's multivariable model yielded significantly unfavorable effects of 1^st ACR (P<.0001; HR=2.492) and severe ACR (P<.0001; HR=4.531). In contrast, when using the time-dependent biased approach, multivariable analysis yielded an incorrect conclusion for the prognostic value of 1^st ACR (P=.31, HR=0.877, 35.2% of 2.492) and a much smaller estimated effect of severe ACR (P=.0008; HR=1.589; 35.1% of 4.531). In conclusion, this study demonstrates the importance of avoiding time-dependent bias when testing the prognostic value of an intervening event.

Addressing sex-based disparities in solid organ transplantation in the United States - a conference report

Solid organ transplantation provides the best treatment for end-stage organ failure, but significant sex-based disparities in transplant access exist. On June 25, 2021, a virtual multidisciplinary conference was convened to address sex-based disparities in transplantation. Common themes contributing to sex-based disparities were noted across kidney, liver, heart, and lung transplantation, specifically the existence of barriers to referral and wait listing for women, the pitfalls of using serum creatinine, the issue of donor/recipient size mismatch, approaches to frailty and a higher prevalence of allosensitization among women. In addition, actionable solutions to improve access to transplantation were identified, including alterations to the current allocation system, surgical interventions on donor organs, and the incorporation of objective frailty metrics into the evaluation process. Key knowledge gaps and high-priority areas for future investigation were also discussed.

Factors associated with frailty in kidney transplant recipients: A cross-sectional study

BACKGROUND

Frailty is prevalent in kidney transplant recipients and associated with multiple health care challenges. The association between frailty and outcomes has been extensively studied in kidney transplant recipients, but the status of frailty and its associated factors are not well studied, hindering efforts to develop strategies to improve care and reduce frailty.

OBJECTIVES

To identify the factors that are associated with frailty in kidney transplant recipients comprehensively.

DESIGN AND PARTICIPANTS

The associated factors of frailty were explored by a cross-sectional study of 185 kidney transplant recipients.

MEASUREMENTS

Data were collected using the general information questionnaire, the Charlson comorbidity index, the Pittsburgh Sleep Quality Index, the Hospital Anxiety and Depression Scale, the Connor-Davidson Resilience Scale, the Perceived Social Support Scale and the Tilburg Frailty Indicator. Data were analyzed using the multiple linear regression analysis.

RESULTS

A total of 75 (40.5%) kidney transplant recipients were assessed as frail by Chinese TFI. Age (β = 0.228), time post-transplant (β = 0.055), sleep quality (β = 0.224) and psychological resilience (β = -0.038) entered the final multiple regression equation and accounted for 41.8% of the total frailty variation (R²  = 0.418, F = 21.31, p < 0.05).

CONCLUSIONS

Frailty was common among kidney transplant recipients. Old age, long time after transplantation, poor sleep quality and low psychological resilience were main associated factors for frailty. Integrated care interventions are therefore needed for this vulnerable population to prevent or delay frailty.

Robotic kidney transplantation from deceased donors: a single-center experience

Robotic-assisted kidney transplant (RAKT) has proven to be a successful approach for patients with elevated body mass index (BMI). To date, a paucity of studies comprehensively analyzing the clinical outcomes of RAKT by using the grafts from deceased donors exists. This was a single-center retrospective analysis of RAKT from deceased donor kidneys (n = 93) from 2009 to 2021. The cohort was divided into 3 groups on the basis of recipient BMI (BMI ≤ 41.2 vs BMI 41.2-44.5 vs BMI ≥ 44.5 kg/m², n = 31). Delayed graft function was significantly higher in the group with the highest BMI (BMI ≤ 41.2 vs BMI 41.2-44.5 vs BMI ≥ 44.5 kg/m², 12.5% vs 10% vs 45.16%, P = .001). Graft survival after 12 months of follow-up was significantly lower in the group with BMI of ≥44.5 kg/m² (BMI ≤ 41.2 vs BMI 41.2-44.5 vs BMI ≥ 44.5 kg/m², 93.7% vs 100% vs 83.9%. P = .05). For BMI, the relative risk of patient survival was 1.10 for each increase in a BMI in the range of 5 (CI 95%, 0.98-1.21). Death-censored graft survival after 5 years was significantly better than the UNOS-matched cohort (dRAKT vs match, 86.2% vs 68.9%, P = .03). This single-center analysis shows that RAKT can be performed safely; however, caution should be used when matching marginal kidneys with patients with high BMI.

Outcomes of kidney transplant recipients who underwent pre-transplant bariatric surgery for severe obesity: a long-term follow-up study

BACKGROUND

Kidney transplantation (KT) is the preferred therapy for end-stage renal disease (ESRD). While a major cause for ESRD, obesity is also a key obstacle to candidacy for KT. Bariatric surgery, particularly sleeve gastrectomy (SG), is increasingly used to improve access to KT in patients with obesity, but the literature especially on outcomes post-KT remains lacking. We aimed to provide a long-term follow-up analysis of efficacy and outcomes of a previously described cohort of patients with obesity, who had SG as a means for access to KT.

METHODS

This is a single-center retrospective follow-up study of 32 patients with advanced chronic kidney disease or ESRD, who were referred and underwent SG between 2013 and 2018 as an access strategy to KT. The primary outcome was successful KT. Ninety-day outcomes, long-term graft function, and changes in weight and obesity-related comorbidities after KT were assessed. Descriptive statistics are presented as count (percentage) or median (interquartile range).

RESULTS

At baseline, 18 (56%) were male with a median age and BMI of 51 (11) years and 42.3 (5.2) kg/m², respectively. Median follow-up time post-SG was 53 (58) months. At last follow-up, 23 (72%) patients received KT. Median time to KT was 16 (20) months and BMI was 34.0 (5.1) kg/m² at time of transplant. At KT, 13 (57%) and 20 (87%) had diabetes and hypertension, respectively. Median follow-up post-KT was 16 (47) months. There was one graft loss requiring return to dialysis. At 5-year post-KT, median serum creatinine was 136 (66) µmol/l. At last follow-up post-KT, median BMI remained at 33.7 (7.6) kg/m². Among patients with diabetes and hypertension, 7/13 (54%) and 5/20 (25%) had either improvement or remission of their comorbidities, respectively.

CONCLUSION

SG is an effective strategy to improve access to KT in patients with severe obesity. Transplant recipients also continue to benefit from sustained weight loss and improved related comorbidities that may positively impact their graft function after KT.

Pretransplant BMI Should Be <25 in Japanese Kidney Transplant Recipients: A Single-Center Experience

BACKGROUND

The aim of this study was to determine the appropriate body mass index (BMI) in Japanese kidney transplant (KTx) recipients. We analyzed the effects of pre- and post-transplant (Tx) obesity on graft and patient survival, perioperative complications, post-transplant diabetes mellitus (PTDM), and cardiovascular disease (CVD) in Japanese KTx recipients.

METHODS

This retrospective study included 269 recipients who underwent KTx from 2008 through 2020 at Niigata University Hospital. Obesity was defined as a body mass index (BMI) ≥25 kg/m². We examined the association between pre- and post-Tx obesity and graft survival, patient survival, the incidence of PTDM and CVD, and perioperative surgical complications.

RESULTS

The graft survival rate was lower in the pre-Tx BMI ≥25 kg/m² group, although there was no significant difference in patient survival. There was no difference in graft and patient survival between the post-Tx BMI ≥25 kg/m² group and the <25 kg/m² group. A pre-Tx BMI ≥25 kg/m² was an independent risk factor for biopsy-proven allograft rejection. New-onset DM after transplantation was significantly more common in the BMI ≥25 kg/m² group than in the BMI <25 kg/m² group (36% vs 13%; P = .002). The incidence of CVD was significantly higher in the post-Tx BMI ≥30 kg/m² group than in the BMI <30 kg/m² group (50% vs 11%; P = .023). There were no differences in surgical operating time, intraoperative blood loss, or perioperative complications between the obese and non-obese groups.

CONCLUSION

Pre-Tx BMI ≥25 kg/m² may be a risk factor for allograft rejection and graft loss. Post-Tx BMI should be <25 kg/m² to reduce the risk for PTDM.

Trends, Social Context, and Transplant Implications of Obesity Among Incident Dialysis Patients in the United States

BACKGROUND

Kidney transplant programs have variable thresholds to accept obese candidates. This study aimed to examine trends and the social context of obesity among United States dialysis patients and implications for kidney transplant access.

METHODS

We performed a retrospective cohort study of 1 084 816 adults who initiated dialysis between January 2007 and December 2016 using the United States Renal Data System data. We estimated national body mass index (BMI) trends and 1-y cumulative incidence of waitlisting and death without waitlisting by BMI category (<18.5 kg/m 2 , ≥18.5 and <25 kg/m 2 [normal weight], ≥25 and <30 kg/m 2 [overweight], ≥30 and <35 kg/m 2 [class 1 obesity], ≥35 and <40 kg/m 2 [class 2 obesity], and ≥40 kg/m 2 [class 3 obesity]). We then used Fine-Gray subdistribution hazard regression models to examine associations between BMI category and 1-y waitlisting with death as a competing risk and tested for effect modification by End Stage Renal Disease (ESRD) network, patient characteristics, and neighborhood social deprivation index.

RESULTS

The median age was 65 (interquartile range 54-75) y, 43% were female, and 27% were non-Hispanic Black. From 2007 to 2016, the adjusted prevalence of class 1 obesity or higher increased from 31.9% to 38.2%. Class 2 and 3 obesity but not class 1 obesity were associated with lower waitlisting rates relative to normal BMI, especially for younger individuals, women, those of Asian race, or those living in less disadvantaged neighborhoods ( pinteraction < 0.001 for all).

CONCLUSIONS

Obesity prevalence is rising among US incident dialysis patients. Relative to normal BMI, waitlisting rates with class 2 and 3 obesity were lower and varied substantially by region, patient characteristics, and socioeconomic context.

Textbook Outcome as a Quality Metric in Living and Deceased Donor Kidney Transplantation

BACKGROUND

Quality in kidney transplantation is measured using 1-year patient and graft survival. Because 1-year patient and graft survival exceed 95%, this metric fails to measure a spectrum of quality. Textbook outcomes (TO) are a composite quality metric offering greater depth and resolution. We studied TO after living donor (LD) and deceased donor (DD) kidney transplantation.

STUDY DESIGN

United Network for Organ Sharing data for 69,165 transplant recipients between 2013 and 2017 were analyzed. TO was defined as patient and graft survival of 1 year or greater, 1-year glomerular filtration rate of greater than 40 mL/min, absence of delayed graft function, length of stay of 5 days or less, no readmissions during the first 6 months, and no episodes of rejection during the first year after transplantation. Bivariate analysis identified characteristics associated with TO, and covariates were incorporated into multivariable models. Five-year conditional survival was measured, and center TO rates were corrected for case complexity to allow center-level comparisons.

RESULTS

The national average TO rates were 54.1% and 31.7% for LD and DD transplant recipients. The hazard ratio for death at 5 years for recipients who did not experience TO was 1.92 (95% CI 1.68 to 2.18, p ≤ 0.0001) for LD transplant recipients and 2.08 (95% CI 1.93 to 2.24, p ≤ 0.0001) for DD transplant recipients. Center-level comparisons identify 18% and 24% of centers under-performing in LD and DD transplantation. High rates of TO do not correlate with transplantation center volume.

CONCLUSION

Kidney transplant recipients who experience TO have superior long-term survival. Textbook outcomes add value to the current standards of 1-year patient and graft survival.

Preoperative blood pressure and risk of delayed graft function in deceased donor kidney transplantation

BACKGROUND

In kidney transplantation, delayed graft function (DGF) is associated with increased morbidity and a higher risk of graft failure. Prior research suggests that chronic hypotension increases DGF risk, but the relationship of preoperative blood pressure to DGF is unclear.

METHODS

In this single center study of adult deceased donor kidney transplant recipients transplanted between 2015 and 2019, we evaluated the question of whether preoperative mean arterial pressure (MAP) affected DGF risk. Additionally, we investigated whether the risk of DGF was moderated by certain donor and recipient characteristics. For recipient characteristics associated with increased DGF risk and preoperative MAP, we performed a mediation analysis to estimate the proportion of DGF risk mediated through preoperative MAP.

RESULTS

Among 562 deceased donor kidney recipients, DGF risk decreased as preoperative MAP increased, with a 2% lower risk per 1 mm Hg increase in MAP. This increased risk was similar, with no statistically significant interaction effect between preoperative MAP and donor (donation after circulatory death) and recipient characteristics (diabetes, body mass index, and use of anti-hypertensive medications). Preoperative MAP was negativity correlated with recipient BMI and duration of pre transplant dialysis. On mediation analysis, MAP accounted for 12% and 16% of the DGF risk associated with recipient BMI and pre-transplant dialysis duration, respectively.

CONCLUSION

In deceased donor kidney transplantation, each 1 mm Hg increase in preoperative MAP was associated with 2% lower DGF risk. Preoperative MAP was influenced by recipient BMI and dialysis duration, and likely contributes to some of the high DGF risk from obesity and long dialysis vintage.

Guiding Kidney Transplantation Candidates for Effective Weight Loss: A Clinical Cohort Study

BACKGROUND

Obesity is increasingly common in kidney transplant candidates and may limit access to transplantation. Obesity and diabetes are associated with a high risk for post-transplant complications. The best approach to weight loss to facilitate active transplant listing is unknown, but bariatric surgery is rarely considered due to patient- and physician-related apprehension, among other factors.

METHODS

We aimed to determine the magnitude of weight loss, listing, and transplant rates in 28 candidates with a mean BMI of 44.4±4.6 kg/m² and diabetes treated conservatively for 1 year post weight-loss consultations (group 1). Additionally, we evaluated 15 patients (group 2) who met the inclusion criteria but received bariatric intervention within the same time frame. All patients completed a multidisciplinary weight management consultation with at least 1 year of follow-up.

RESULTS

In the conservatively managed group (group 1), the mean weight at the time of initial consultation was 126.5±18.5 kg, and the mean BMI was 44.4±4.6 kg/m². At 1 year post weight-loss consultation, the mean weight decreased by 4.4±8.2 kg to 122.9±17 kg, and the mean BMI was 43±4.8 kg/m², with a total mean body weight decrease of 3% (P=0.01). Eighteen patients (64%) did not progress to become candidates for active listing/transplantation during the follow-up time of 4±2.9 years, with 15 (54%) subsequently developing renal failure/diabetes-related comorbidities prohibitive for transplantation. In contrast, mean total body weight decreased by 19% at 6 months post bariatric surgery, and the mean BMI was 34.2±4 and 32.5±3.7 kg/m² at 6 and 12 months, respectively. Bariatric surgery was strongly associated with subsequent kidney transplantation (HR=8.39 [95% CI 1.71 to 41.19]; P=0.009).

CONCLUSIONS

A conservative weight-loss approach involving multidisciplinary consultation was ineffective in most kidney transplant candidates with diabetes, suggesting that a more proactive approach is needed.

Pretransplant BMI Significantly Affects Perioperative Course and Graft Survival after Kidney Transplantation: A Retrospective Analysis

Background. The number of kidney transplant recipients (KTRs) with overweight and obesity is increasing. It was shown that obesity is related to inferior patient and graft survival. We aimed to analyze intraoperative parameters and postoperative short and long-term course of kidney transplantation (KT) in body mass index (BMI)-stratified cohorts of KTRs. Methods. A retrospective analysis of a prospectively built database of 433 KTRs from 2014 to 2017 from a single transplant center was performed. The objective of the study was to analyze the association between BMI at the time of transplantation with intraoperative parameters, adverse events in early postoperative course, and the overall mortality and graft loss in BMI-stratified cohorts: normal (18.5 and 24.9 kg/m2), overweight (25−29.9 kg/m2) and obese (≥30 kg/m2). Results. Obesity was related to longer total procedure time (p = 0.0025) and longer warm ischemia time (p = 0.0003). The postoperative course in obese patients was complicated by higher incidence of DGF (delayed graft function), early surgical complications (defined as surgical complications <30 days from KT), reoperation rate, vascular complications, incidence of lymphocele and wound dehiscence. There was no difference between the normal weight and overweight KTRs. The one-month kidney function (p = 0.0001) and allograft survival (p = 0.029) were significantly inferior in obese patients with no difference between normal weight and overweight patients. One-year death-censored graft survival was better in patients with BMI < 30 (88.6 vs. 94.8% p = 0.05). BMI was a significant predictor of graft loss in univariate (p = 0.04) but not in multivariate analysis (p = 0.09). Conclusion. Pretransplant obesity significantly affects the intraoperative and postoperative course of kidney transplantation and graft function and survival. The course of transplantation of overweight is comparable to normal BMI KTRs, and presumably pretransplant weight reduction to the BMI < 30 kg/m2 may improve the short-term postoperative course of transplantation as well as may improve graft survival. Thus, pretransplant weight reduction in obese KTRs may significantly improve the results of kidney transplantation. Metabolic surgery may play a role in improving results of KT.

Whole-exome sequencing identified mutational profiles of urothelial carcinoma post kidney transplantation

Kidney transplantation is a lifesaving option for patients with end-stage kidney disease. In Taiwan, urothelial carcinoma (UC) is the most common de novo cancer after kidney transplantation (KT). UC has a greater degree of molecular heterogeneity than do other solid tumors. Few studies have explored genomic alterations in UC after KT. We performed whole-exome sequencing to compare the genetic alterations in UC developed after kidney transplantation (UCKT) and in UC in patients on hemodialysis (UCHD). After mapping and variant calling, 18,733 and 11,093 variants were identified in patients with UCKT and UCHD, respectively. We excluded known single-nucleotide polymorphisms (SNPs) and retained genes that were annotated in the Catalogue of Somatic Mutations in Cancer (COSMIC), in the Integrative Onco Genomic cancer mutations browser (IntOGen), and in the Cancer Genome Atlas (TCGA) database of genes associated with bladder cancer. A total of 14 UCKT-specific genes with SNPs identified in more than two patients were included in further analyses. The single-base substitution (SBS) profile and signatures showed a relative high T > A pattern compared to COMSIC UC mutations. Ingenuity pathway analysis was used to explore the connections among these genes. GNAQ, IKZF1, and NTRK3 were identified as potentially involved in the signaling network of UCKT. The genetic analysis of posttransplant malignancies may elucidate a fundamental aspect of the molecular pathogenesis of UCKT.

Balancing Equity and Efficiency in Kidney Allocation: An Overview

Organs for transplantation are a scarce resource. Markedly, the transplant community's primary challenge is the stark disparity between the number of patients awaiting deceased donor organ transplants and the rate at which organs become available. However, the allocation of a limited number of organs poses another constant challenge: maintaining an equilibrium between renal transplant utility and equity, that is, striking a balance between the utilitarian argument of medical efficiency and the principle of equity. In this comprehensive overview, the authors delve into the challenge of maintaining an acceptable balance between equity and efficiency and elaborate on some of the factors that might inform a decisionmaker's evaluation of the extent to which a given allocation scheme is efficient or equitable.

Effect of pre and post-transplant body mass index on pediatric kidney transplant outcomes

Introduction

Kidney transplantation (KT) has been established as an efficient treatment of end stage renal disease (ESRD) with the advantage of allowing the patient to live a nearly healthy life. We aimed to determine whether pre-transplant body mass index (BMI) affects renal allograft function and survival in pediatric KT recipients.

Methods

cross sectional cohort study included 50 post KT recipients (more than 3 years) with an age range of 10 to 15 years, regularly following at the Kidney Transplantation Outpatient Clinic, Cairo University Children’s Hospital, were subjected to a detailed history and physical examination, laboratory investigation in the form of fasting blood glucose (FBG),oral glucose tolerance test (OGTT), lipid profile, hemoglobin A1c (HbA1c) and microalbuminuria.

Results

Pre- post- kidney transplant BMI has significant positive correlation with graft rejection episodes, HbA1c, FBG, BMI post-KT, total cholesterol, triglycerides, and low-density lipoprotein (p < 0.01). There was a statistically significant negative correlation between the mean difference of BMI (post – pre) and graft survival in years (p = 0.036). Obese patients displayed lower survival compared with non-obese subjects at 5 years, but this was statistically not significant (p-value = 0.165).

Conclusion

obesity is an independent risk factor for graft loss and patient death in kidney transplantation. Careful patient selection with pre-transplantation weight reduction is mandatory to reduce the rate of early post-transplantation complications and to improve long-term outcomes.

The application of body mass index-based eligibility criteria may represent an unjustified barrier to renal transplantation in people with obesity

The prevalence of both obesity and end-stage kidney disease is increasing. In many centres, obesity is considered a relative contraindication to kidney transplantation due to an association with short- and longer-term adverse outcomes. This leads to delayed transplant waitlisting and longer organ waiting times for people with obesity. This review evaluates whether intentional pre-transplant weight loss in people with obesity improves kidney transplant outcomes. There are currently no data showing that non-surgical weight loss of 10% or more improves graft or patient survival over 4-5 years. Outcomes from bariatric surgery cohorts have been generally neutral or favourable after pre-transplant weight loss of ~25%. Given the survival benefit of kidney transplantation compared to maintenance dialysis, and the difficulty of achieving and maintaining weight loss, the common practice of recommending weight loss to achieve arbitrary targets prior to waiting list activation needs to be carefully considered.

Robotic Kidney Transplant: The Modern Era Technical Revolution

Since the mid 20th century, transplantation has been a fast-developing field of contemporary medicine. The technical aspects of transplant operations were developed in the 1950s, with little significant change for >50 y. Those techniques allowed completion of various organ transplants and successful patient outcomes, but they also carried the inherent disadvantages of open surgery, such as postoperative pain, wound complications and infections, and prolonged length of hospital stay. The introduction and adoption of minimally invasive surgical techniques in the early 1990s to various surgical specialties including general, gynecologic, and urologic surgery led to significant improvements in postoperative patient care and outcomes. Organ transplantation, with its precision demanding vascular anastomoses, initially had been considered infeasible to accomplish with conventional laparoscopic devices. The institution of robotic surgical technology in the late 1990s and its subsequent wide utilization in fields of surgery changed its accessibility and acceptance. With the steady camera, 3D views, and multidirectional wrist motions, surgical robotics opened new horizons for technically demanding surgeries such as transplantation to be completed in a minimally invasive fashion. Furthermore, the hope was this technique could find a niche to treat patients who otherwise are not deemed surgical candidates in many fields including transplantation. Here in, robotics in kidney transplantation and its ability to help provide equity through access to transplantation will be discussed.

Surgical Wound Dehiscence in Kidney Transplantation: Risk Factors and Impact on Graft Survival

BACKGROUND

Surgical wound dehiscence (SWD) is a frequent complication after kidney transplantation (KT) but there is not enough evidence of its impact on graft survival.

METHODS

A retrospective cohort study including all KT patients with SWD in our center from January 2015 to July 2020 was performed. A case-control study was performed and for each case of SWD, 2 controls were selected (2:1). To identify risk factors for SWD, a logistic regression analysis was carried out and a multivariable Cox regression was used to describe risk factors for graft survival.

RESULTS

In our center, 503 KT were performed, and 39 patients presented SWD. They were older (62.1 vs 57.1 years; P = .030), most had diabetes mellitus (59% vs 28.6%; P = .002) and their body mass index was higher (31 vs 26.9 kg/m²; P < .001). In multivariable logistic regression analysis, diabetes mellitus (P = .024) and a body mass index ≥30 kg/m² at time of transplantation (P = .018) were predictors of SWD. A higher rate of delayed graft function was described in SWD (P = .013) and it was associated with a longer hospital stay (20.9 vs 15 days; P = .004). Graft survival was lower in patients with SWD (P = .036). In multivariable Cox regression analysis, time in renal replacement therapy (P = .020) and SWD (P = .028) were predictors of shorter graft survival.

CONCLUSION

SWD is a risk factor for graft survival. The presence of diabetes mellitus and a higher body mass index are predictors for the appearance of this complication.

Management of obesity in kidney transplant candidates and recipients: A clinical practice guideline by the Descartes working group of ERA

The clinical practice guideline Management of Obesity in Kidney Transplant Candidates and Recipients was developed to guide decision-making in caring for people with end-stage kidney disease (ESKD) living with obesity. The document considers the challenges in defining obesity, weighs interventions for treating obesity in kidney transplant candidates as well as recipients and reflects on the impact of obesity on the likelihood of wait-listing as well as its effect on transplant outcomes. It was designed to inform management decisions related to this topic and provide the backdrop for shared decision-making. This guideline was developed by the European Renal Association’s Developing Education Science and Care for Renal Transplantation in European States working group. The group was supplemented with selected methodologists to supervise the project and provide methodological expertise in guideline development throughout the process. The guideline targets any healthcare professional treating or caring for people with ESKD being considered for kidney transplantation or having received a donor kidney. This includes nephrologists, transplant physicians, transplant surgeons, general practitioners, dialysis and transplant nurses. Development of this guideline followed an explicit process of evidence review. Treatment approaches and guideline recommendations are based on systematic reviews of relevant studies and appraisal of the quality of the evidence and the strength of recommendations followed the Grading of Recommendations Assessment, Development and Evaluation approach. Limitations of the evidence are discussed and areas of future research are presented.

Obesity Management in Kidney Transplant Candidates: Current Paradigms and Gaps in Knowledge

In this review, we discuss the increasing prevalence of obesity among people with chronic and end-stage kidney disease (ESKD) and implications for kidney transplant (KT) candidate selection and management. Although people with obesity and ESKD receive survival and quality-of-life benefits from KT, most KT programs maintain strict body mass index (BMI) cutoffs to determine transplant eligibility. However, BMI does not distinguish between visceral adiposity, which confers higher cardiovascular risks and risks of perioperative and adverse posttransplant outcomes, and muscle mass, which is protective in ESKD. Furthermore, requirements for patients with obesity to lose weight before KT should be balanced with the findings of numerous studies that show weight loss is a risk factor for death among patients with ESKD, independent of starting BMI. Data suggest that KT is associated with survival benefits relative to remaining on dialysis for candidates with obesity although recipients without obesity have higher delayed graft function rates and longer transplant hospitalization durations. Research is needed to determine the optimal body composition metrics for KT candidacy assessments and risk stratification. In addition, ESKD-specific obesity management guidelines are needed that will address the neurologic, behavioral, socioeconomic, and physical underpinnings of this increasingly common disease.

But Why Weight: Understanding the Implications of Obesity in Kidney Transplant

Obesity is increasing in prevalence among candidates for kidney transplant. Understanding the influence of obesity on candidate evaluation, surgical risk, peritransplant management, and post-transplant outcomes is critical to ensuring equitable access to transplant for this growing population.

Impact of obesity in kidney transplantation: a prospective cohort study from French registries between 2008 and 2014

BACKGROUND

The access of obese patients to kidney transplantation is limited despite several studies showing that obese transplant recipients had a better survival rate than those undergoing dialysis. The aim of this study was to compare patient and graft survival rates and post-renal transplant complications in obese patients and non-obese patients and to assess the effect of pre-transplant weight loss in obese patients on transplant outcomes.

METHODS

We carried out a prospective cohort study using two French registries REIN and CRISTAL on 7 270 kidney transplant patients between 2008 and 2014 in France. We compared obese patients with non-obese patients and obese patients who lost more than 10% of weight before the transplant (Obese WL and Obese nWL).

RESULTS

The mean BMI in our obese patients was 32 kg/m2. Graft survival was lower in obese patients than in non-obese patients (HR = 1.40, IC 95% [1.09; 1.78], P = 0.007) whereas patient survival was similar (HR = 0.94, IC 95% [0.73; 1.23], P = 0.66). Graft survival was significantly lower in Obese WL than in Obese nWL (HR = 2.17, CI 95% [1.02; 4.63], P = 0.045) whereas patient survival was similar in the two groups (HR = 0.79, IC 95% [0.35; 1.77], P = 0.56).

CONCLUSION

Grade I obesity does not seem to be a risk factor for excess mortality after kidney transplantation and should not be an obstacle to having access to a graft. Weight loss before a kidney transplant in this patients should not be essential for registration on waiting list.

Robot-assisted kidney transplantation is a safe alternative approach for morbidly obese patients with end-stage renal disease

BACKGROUND

Many centres deny obese patients with a body mass index (BMI) >35 access to kidney transplantation due to increased intraoperative and postoperative complications.

METHODS

From August 2017 to December 2019, 73 consecutive cases of kidney transplantation in morbidly obese patients were enrolled at a single university at the initiation of a robotic transplant surgery program. Outcomes of patients who underwent robotic assisted kidney transplant (RAKT) were compared to frequency-matched patients undergoing open kidney transplant (OKT).

RESULTS

A total of 24 morbidly obese patients successfully underwent RAKT, and 49 obese patients received an OKT. The RAKT group developed fewer surgical site infections (SSI) than the OKT group. Graft function, creatinine, and glomerular filtration rate (GFR) were similar between groups 1 year after surgery. Graft and patient survival were 100% for both groups.

CONCLUSIONS

RAKT offers a safe alternative for morbidly obese patients, who may otherwise be denied access to OKT.

Obesity and bariatric surgery in kidney transplantation: A clinical review

Obesity is increasing worldwide, and this has major implications in the setting of kidney transplantation. Patients with obesity may have limited access to transplantation and increased posttransplant morbidity and mortality. Most transplant centers incorporate interventions aiming to target obesity in kidney transplant candidates, including dietary education and lifestyle modifications. For those failing nutritional restriction and medical therapy, the use of bariatric surgery may increase the transplant candidacy of patients with obesity and end-stage renal disease (ESRD) and may potentially improve the immediate and late outcomes. Bariatric surgery in ESRD patients is associated with weight loss ranging from 29.8% to 72.8% excess weight loss, with reported mortality and morbidity rates of 2% and 7%, respectively. The most commonly performed bariatric surgical procedures in patients with ESRD and in transplant patients are laparoscopic sleeve gastrectomy (LSG) and laparoscopic Roux-en-Y gastric bypass. However, the correct timing of bariatric surgery and the ideal type of surgery have yet to be determined, although pretransplant LSG seems to be associated with an acceptable risk-benefit profile. We review the impact of obesity on kidney transplant candidates and recipients and in potential living kidney donors, exploring the potential impact of bariatric surgery in addressing obesity in these populations, thereby potentially improving posttransplant outcomes.

Obesity as an isolated contraindication to kidney transplantation in the end-stage renal disease population: A cohort study

OBJECTIVE

The aim of this study was to characterize end-stage renal disease (ESRD) patients with obesity as their only contraindication to listing and to quantify wait-list and transplant access.

METHODS

Using the US Renal Data System, a retrospective cohort study of incident dialysis cases (2012 to 2014) was performed. The primary outcomes were time to wait-listing and time to transplantation.

RESULTS

Of 157,572 dialysis patients not already listed, 39,844 had BMI as their only demonstrable transplant contraindication. They tended to be younger, female, and Black. Compared with patients with BMI < 35, those with BMI 35 to 39.9, 40 to 44.9, and ≥45 were, respectively, 15% (adjusted hazard ratio [aHR] 0.85; 95% CI: 0.83-0.88; p < 0.001), 45% (aHR 0.55; 95% CI: 0.52-0.57; p < 0.001), and 71% (aHR 0.29; 95% CI: 0.27-0.31; p < 0.001) less likely to be wait-listed. Wait-listed patients with BMI 35 to 39.9 were 24% less likely to achieve transplant (aHR 0.76; 95% CI: 0.72-0.80; p < 0.0001), BMI 40 to 44.9 were 21% less likely (aHR 0.79; 95% CI: 0.72-0.86; p < 0.0001), and BMI ≥ 45 were 15% less likely (aHR 0.85; 95% CI: 0.75-0.95; p = 0.004) compared with patients with BMI < 35.

CONCLUSIONS

Obesity was the sole contraindication to wait-listing for 40,000 dialysis patients. They were less likely to be wait-listed. For those who were, they had a lower likelihood of transplant. Aggressive weight-loss interventions may help this population achieve wait-listing and transplant.