Obesity and kidney transplantation

Kidney Transplant: More than Immunological Problems

Kidney transplantation (KT) represents a pivotal intervention for patients with chronic kidney disease (CKD), significantly improving survival and quality of life. However, KT recipients face an array of non-immunological complications, collectively amplifying cardiovascular (CV) and metabolic risks. This review explores the intersection of cardio-metabolic syndrome and KT, emphasizing the recently introduced cardiovascular-kidney-metabolic (CKM) syndrome. CKM syndrome integrates metabolic risk factors, CKD, and CV disease, with KT recipients uniquely predisposed due to immunosuppressive therapies and pre-existing CKD-related risks. Key issues include post-transplant hypertension, obesity, dyslipidemia, post-transplant diabetes mellitus (PTDM), and anemia. Immunosuppressive agents such as corticosteroids, calcineurin inhibitors, and mTOR inhibitors contribute significantly to these complications, exacerbating metabolic dysfunction, insulin resistance, and lipid abnormalities. For instance, corticosteroids and calcineurin inhibitors heighten the risk of PTDM, while mTOR inhibitors are strongly associated with dyslipidemia. These pharmacologic effects underscore the need for tailored immunosuppressive strategies. The management of these conditions requires a multifaceted approach, including lifestyle interventions, pharmacological therapies like SGLT2 inhibitors and GLP-1 receptor agonists, and close monitoring. Additionally, emerging therapies hold promise in addressing metabolic complications in KT recipients. Proactive risk stratification and early intervention are essential to mitigating CKM syndrome and improving outcomes. This comprehensive review highlights the importance of integrating cardio-metabolic considerations into KT management, offering insights into optimizing long-term recipient health and graft survival.

Deceased donor urinary Dickkopf-3 associates with future allograft function following kidney transplantation

Predicting future kidney allograft function is challenging. Novel biomarkers, such as urinary Dickkopf-3 (uDKK3), may help guide donor selection and improve allograft outcomes. In this prospective multicenter pilot trial, we investigated whether donor uDKK3 reflects organ quality and is associated with future allograft function. We measured uDKK3/crea ratios (uDKK3/crea) from 95 deceased and 46 living kidney donors. Prenephrectomy uDKK3/crea levels were 100× higher in deceased than in living donors (9888 pg/mg vs 113 pg/mg; P < .001). Among deceased donor transplantations, recipients were stratified by their corresponding uDKK3/crea donor levels ranging below (group A, n = 68) or above (group B, n = 65) median. The primary end point of best estimated glomerular filtration rate (eGFR) within the first 3 months after kidney transplantation was superior in group A (56.3 mL/min/1.73 m2) than that in group B (44.2 mL/min/1.73 m2; P = .0139). Second, the composite clinical end point consisting of death, allograft failure or eGFR decline >50% occurred less frequent in group A. By mixed linear regression modeling, donor uDKK3/crea remained an independent predictor of eGFR after transplantation, with a slope of -4.282 mL/min/1.73 m2 per logarithmic increase in donor uDKK3/crea. In summary, uDKK3 may serve as a noninvasive, donor-dependent biomarker for assessing organ quality and future allograft function.

The use of virtual reality-assisted interventions on psychological well-being and treatment adherence among kidney transplant recipients: A randomized controlled study

This randomized controlled trial aims to investigate the effects of educational and psychological interventions on the health outcomes of patients suffering from chronic diseases. We recruited 372 patients and randomly assigned them to one of two intervention arms during the trial, which lasted for a year. Both groups participated in a 12-month intervention program, where the intervention group received health education and supportive psychological therapy utilizing virtual reality (VR) technology, while the control group received conventional health education guidance. Statistical analysis showed that compared to the control group, the intervention group demonstrated significant improvements (p < 0.05) in depression assessment scores, compliance scores, and Barthel functional scoring. However, the two groups had no significant difference in the incidence of complications and health knowledge mastery. Additionally, the intervention group had fewer hospitalization days than the control group, with statistically significant differences. The research results prove that targeted intervention effectively improves medication adherence, patient awareness, and reduces patient hospitalization days, which is particularly important for managing chronic diseases.

The evaluation of kidney transplant candidates prior to waitlisting: a scoping review

Before patients with kidney failure can undergo kidney transplantation, their suitability is assessed through a transplantation work-up. Variation in the transplantation work-up could contribute to inefficiency and inequality in accessing the transplant waiting list and kidney transplantation. We conducted a scoping review on the evaluation of kidney transplant candidates prior to waitlisting, investigating: (i) content of the transplantation work-up; (ii) contraindications to waitlisting; and (iii) organization of the transplantation work-up. A systematic search was conducted in Ovid Medline and Ovid EMBASE in collaboration with a medical information specialist. Studies investigating practice patterns since 2013 related to the evaluation of adults receiving their first kidney graft from a deceased donor were included. Results from 20 studies showed substantial variation in the evaluation of kidney transplant candidates. The content of the transplantation work-up differed between studied centers, yet common domains included screening for infections, heart disease, peripheral artery disease, and malignancy. Commonly reported contraindications to waitlisting were obesity and age-related factors. However, strict cut-off for BMI and age were used less. The organization of the transplantation work-up differed across studied centers with regard to referral and waitlisting decisions, screening and prioritization, and the setting of the transplantation work-up. Literature on the evaluation of kidney transplant candidates is limited, but our findings suggest substantial variation in pre-waitlisting practices among centers. This may contribute to differences in kidney transplantation access and outcomes between countries. Further research on pre-transplantation practices, specifically regarding the standardization of the transplantation work-up, is needed.

Mental and Physical Readiness for Weight Loss After Abdominal Organ Transplant

INTRODUCTION

Readiness to incorporate healthy lifestyle practices is not studied in posttransplant patients. We evaluate physical and mental readiness for a weight-loss guided lifestyle intervention.

METHODS

12 kidney and 12 liver transplant patients were given a Fitbit and weighing scale for 12 mo. Twelve patients received group sessions on lifestyle modifications. Mental readiness was assessed using Patient Activation Measurement-13, Physical Activity, Process of Change, and Weight Stages of Change. Physical readiness was assessed using Fatigue, Resistance, Ambulation, Illness, and Loss of Weight, and Short Physical Performance Battery questionnaires. Weight change, group session attendance, device usage, and readiness were analyzed.

RESULTS

23 patients (12 kidney, 11 liver), 57 y (46.2-67.5), 75% male, 24.9 (15.7-43.2) months posttransplant) completed the study. Twenty-two patients had robust physical readiness, and high Fitbit usage (>80%). Ten patients (43%) lost ≥2.5% (moderate) of body weight, including 4 (17.3%) losing >5% total weight (high). 13 patients lost ≤2.5% or gained weight (maintenance). High loss and target group session attendance groups had the highest use of Processes of Change.

CONCLUSIONS

Posttransplant patients are physically ready for a weight-loss guided lifestyle intervention and show high usage of the Fitbit device. Higher mental readiness associates with higher weight loss.

A holistic review of sodium intake in kidney transplant patients: More questions than answers

Kidney transplantation (KT) is the best treatment option for end-stage kidney disease (ESKD). Acute rejection rates have decreased drastically in recent years but chronic kidney allograft disease (CKAD) is still an important cause of allograft failure and return to dialysis. Thus, there is unmet need to identify and reverse the cause of CKAD. Additionally, cardiovascular events after KT are still leading causes of morbidity and mortality. One overlooked potential contributor to CKAD and adverse cardiovascular events is increased sodium/salt intake in kidney transplant recipients (KTRs). In general population, the adverse effects of high sodium intake are well known but in KTRs, there is a paucity of evidence despite decades of experience with KT. Limited research showed that sodium intake is high in most KTRs. Moreover, excess sodium intake is associated with elevated blood pressure and albuminuria in some studies involving KTRs. There is also experimental evidence suggesting that increased sodium intake is associated with histologic graft damage. Critical knowledge gaps still remain, including the exact amount of sodium restriction needed in KTRs to optimize outcomes and allograft survival. Additionally, best methods to measure sodium intake and practices to follow-up are not clarified in KTRs. To meet these deficits, prospective long term studies are warranted in KTRs. Moreover, preventive measures must be determined and implemented both at individual and societal levels to achieve sodium restriction in KTRs.

Timing Considerations for Sleeve Gastrectomy in Kidney Transplant Patients: A Single Center Evaluation

Current scientific literature is deficient in detailing the optimal timing for conducting bariatric surgery in relation to kidney transplantation. In this study, we performed a retrospective evaluation of kidney transplant recipients with BMI >35 kg/m2. It aimed to provide data on those who received both sleeve gastrectomy (SG) and kidney transplantation (KT) simultaneously, as well as on patients who underwent SG and KT at different times, either before or after. In addition, the acceptance levels of the bariatric surgery among different scenarios were assessed. Our findings demonstrated that combined KT and SG led to successful weight loss, in contrast to undergoing kidney transplant alone, while maintaining comparable rates of graft and patient survival. Weight loss was similar between recipients who had a combined operation and those who underwent SG following the transplant. Additionally, over a median time frame of 1.7 years, patients who underwent SG before KT exhibited a statistically significant reduction in BMI at the time of the transplant. Notably, our study highlights that patients offered the combined procedure were significantly more likely to undergo SG compared to those for whom SG was presented at a different operative time than the transplant.

Cardiometabolic comorbidities and complications of obesity and chronic kidney disease (CKD)

Obesity and chronic kidney disease are two ongoing progressive clinical pandemics of major public health and clinical care significance. Because of their growing prevalence, chronic indolent course and consequent complications both these conditions place significant burden on the health care delivery system especially in developed countries like the United States. Beyond the chance coexistence of both of these conditions in the same patient based on high prevalence it is now apparent that obesity is associated with and likely has a direct causal role in the onset, progression and severity of chronic kidney disease. The causes and underlying pathophysiology of this are myriad, complicated and multi-faceted. In this review, continuing the theme of this special edition of the journal on " The Cross roads between Endocrinology and Nephrology" we review the epidemiology of obesity related chronic kidney disease (ORCKD), and its various underlying causes and pathophysiology. In addition, we delve into the consequent comorbidities and complications associated with ORCKD with particular emphasis on the cardio metabolic consequences and then review the current body of evidence for available strategies for chronic kidney disease modulation in ORCKD as well as the potential unique role of weight reduction and management strategies in its improvement and risk reduction.

Obesity is associated with a higher incidence of rejection in patients on belatacept: A pooled analysis from the BENEFIT/BENEFIT-EXT clinical trials

Though belatacept is administered with a weight-based dosing schema, there has been higher clearance reported in obese patients. Therefore, we evaluated the association between body mass index (BMI) and transplant outcomes in kidney transplant recipients who were randomized to cyclosporine- or belatacept-based immunosuppression in the BENEFIT and BENEFIT-EXT randomized clinical trials. A total of 666 and 543 patients underwent randomization and transplantation in BENEFIT and BENEFIT-EXT, respectively, of which 1056 had complete data and were included in this analysis. Patients were grouped categorically according to BMI: <25, 25 to <30, and ≥30 kg/m2. BMI did influence both the incidence and severity of acute rejection. Obese patients with BMI >30 kg/m2 in the low intensity belatacept group experienced significantly more rejection at 12 months than did patients with BMI <25 kg/m2 or BMI 25 to <30 kg/m2. In both the moderate intensity belatacept and low intensity belatacept groups, obese patients with BMI >30 kg/m2 experienced significantly more severe acute rejection than did patients with BMI < 25 kg/m2 or BMI 25 to <30 kg/m2. These results suggest that obese kidney transplant recipients are at an increased risk for acute rejection when under belatacept-based immunosuppression when compared to nonobese patients.

KDOQI Commentary on the KDIGO 2022 Update to the Clinical Practice Guideline for Diabetes Management in CKD

The Kidney Disease: Improving Global Outcomes (KDIGO) guideline for diabetes management in chronic kidney disease (CKD) was updated in 2022, just 2 years after the previous update. The need for this rapid update is reflective of the recent and unprecedented positive results of numerous clinical trials aimed at reducing kidney and cardiovascular morbidity and mortality in people with diabetes. The Kidney Disease Outcomes Quality Initiative (KDOQI) work group for diabetes in CKD, convened by the National Kidney Foundation, provides herein a commentary on these changes, particularly the implications for health care in the United States. Changes to the KDIGO guideline mirror the evolution of sodium/glucose cotransporter 2 (SGLT2) inhibitors and glucagon-like peptide 1 receptor agonists from purely antihyperglycemic agents to cardiorenal-metabolic therapeutics, and the lower estimated glomerular filtration rate of≥20mL/min/1.73m2 for SGLT2 inhibitor initiation. New data have also brought the addition of the first-in-class, Federal Drug Administration-approved nonsteroidal mineralocorticoid receptor antagonist finerenone as an agent to reduce cardiorenal end points. While there has been significant progress in innovation, there remain serious challenges to implementation, particularly in the United States where inequities in insurance coverage and high costs limit their use, particularly in vulnerable populations, ultimately widening health care disparities.

The Relationship Between Weight Indices and Blood Levels of Immunosuppressive Drugs in Renal Transplant Recipients

Background

Calcineurin inhibitors and mammalian target of rapamycin (mTOR) inhibitors are essential for maintaining transplanted organs. However, determining the appropriate dosage and predicting blood concentrations of these drugs based solely on net body weight may be inadequate. Previous studies have presented contradictory results regarding the impact of obesity on drug concentrations and transplant success.

Objectives

This study aims to evaluate various weight indices to identify the most reliable indicator of weight that correlates with the blood levels of drugs used in organ transplantation.

Methods

This retrospective descriptive study included patients from nephrology clinics affiliated with Isfahan University of Medical Sciences who were taking calcineurin and/or mTOR inhibitor drugs. Data extracted from medical records included demographic and clinical information, such as height, weight, and various weight indices (total/ideal/adjusted body weight, lean body mass (LBM), Body Mass Index, and predicted normal weight), as well as blood levels of immunosuppressive drugs at each patient's visit. The dosages of each drug (mg/kg) were analyzed to determine which weight indices best correlated with the obtained blood concentrations, using the Generalized Estimating Equation (GEE) model with logistic regression, an independent correlation matrix, and a binary distribution for data analysis.

Results

The study analyzed the medical records of 71 patients. Trough (C0) concentrations of drugs were evaluated in relation to each weight index, and odds ratios (OR) were calculated for statistical comparison. All weight indices increased the likelihood of achieving appropriate concentrations for cyclosporine, tacrolimus, and sirolimus. Drug dosing based on LBM (OR: 1.028), ideal body weight (OR: 1.075), and total body weight (OR: 1.041) showed the strongest correlations with achieving proper blood levels for cyclosporine, tacrolimus, and sirolimus, respectively.

Conclusions

Integrating various weight indices for calculating individualized doses (mg/kg) of each immunosuppressive drug increases the likelihood of achieving appropriate blood concentrations. However, the optimal weight index varies for each drug. Further studies, particularly those incorporating therapeutic drug monitoring (TDM) plans in transplant centers, are warranted to validate and generalize these findings, providing a potential avenue for improving immunosuppressive therapy and enhancing transplant outcomes.

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.

Obesity-Related Kidney Disease: Current Understanding and Future Perspectives

Obesity is a serious chronic disease and an independent risk factor for the new onset and progression of chronic kidney disease (CKD). CKD prevalence is expected to increase, at least partly due to the continuous rise in the prevalence of obesity. The concept of obesity-related kidney disease (OKD) has been introduced to describe the still incompletely understood interplay between obesity, CKD, and other cardiometabolic conditions, including risk factors for OKD and cardiovascular disease, such as diabetes and hypertension. Current therapeutics target obesity and CKD individually. Non-pharmacological interventions play a major part, but the efficacy and clinical applicability of lifestyle changes and metabolic surgery remain debatable, because the strategies do not benefit everyone, and it remains questionable whether lifestyle changes can be sustained in the long term. Pharmacological interventions, such as sodium-glucose co-transporter 2 inhibitors and the non-steroidal mineralocorticoid receptor antagonist finerenone, provide kidney protection but have limited or no impact on body weight. Medicines based on glucagon-like peptide-1 (GLP-1) induce clinically relevant weight loss and may also offer kidney benefits. An urgent medical need remains for investigations to better understand the intertwined pathophysiologies in OKD, paving the way for the best possible therapeutic strategies in this increasingly prevalent disease complex.