Higher recipient body mass index is associated with post-transplant delayed kidney graft function. Kidney Int. 2011;80:218-224. [PMID: 21525853 DOI: 10.1038/ki.2011.114]

The Use of Semaglutide in Patients With Renal Failure-A Retrospective Cohort Study

OBJECTIVE

Semaglutide, a glucagon-like peptide-1 receptor agonist is approved for weight loss and diabetes treatment, but limited literature exists regarding semaglutide use in patients with advanced chronic kidney disease (CKD). Therefore, this project assessed the safety and efficacy of semaglutide among patients with estimated glomerular filtration rate (eGFR) 15-29 mL/min/1.73 m2 (CKD stage 4), eGFR<15 mL/min/1.73 m2 (CKD stage 5) or on dialysis.

METHODS

This is a retrospective electronic medical record based analysis of consecutive patients with advanced CKD (defined as CKD 4 or greater) who were started on semaglutide (injectable or oral). Data was collected between January 2018 and January 2023. Investigators verified CKD diagnosis and manually extracted data. Data were analyzed using Fisher's exact test, paired t test, linear mixed effects models and Wilcoxon signed rank test.

RESULTS

Seventy-six patients with CKD 4 or greater who initiated semaglutide were included. Most patients had a history of type 2 diabetes mellitus (96.0%), and most were males (53.9%). The mean age was 66.8 y (SD 11.5) with the mean body mass index was 36.2 (SD 7.5). The initial doses were 3 mg orally and 0.25 mg by injection. Maximum prescribed dose was 1 mg (injectable) in 28 (45.2%) patients and 14 mg (orally) in 2 (14.2%) patients. Patients received semaglutide for a median duration of 17.4 (IQR 0.43, 48.8) months. Forty-eight (63.1%) patients reported no adverse effects associated with the therapy. Mean weight decreased from 106.2 (SD 24.2) to 101.3 (SD 27.3) kg (P < .001). Eight patients (16%) with type 2 diabetes mellitus T2DM discontinued insulin after starting semaglutide. Mean hemoglobin A1c (HbA1c) decreased from 8.0% (SD 1.7) to 7.1% (SD 1.3) (P < .001). Adverse effects were the primary reason for semaglutide discontinuation (37.0%), with nausea, vomiting, and abdominal pain being the most common complaints.

CONCLUSIONS

Based on this retrospective study semaglutide appears to be tolerated by most individuals with CKD 4 or greater despite associated gastrointestinal side effects similar to those observed in patients with better kidney function and leads to an improvement of glycemic control and insulin discontinuation in patients with T2DM. Modest weight loss (approximately 4.6% of the total body weight) was observed on the prescribed doses. Larger prospective randomized studies are needed to comprehensively assess the risks and benefits of semaglutide in patients with CKD 4 or greater and obesity.

Risk factors of delayed graft function following living donor kidney transplantation: A meta-analysis

INTRODUCTION

Delayed graft function (DGF) is a common condition that necessitates dialysis during the first week after transplantation. Although DGF rarely occurs following living-donor kidney transplantation (LDKT), it may eventually lead to acute or chronic graft rejection. This study aimed to assess the risk factors for DGF in patients who underwent LDKT.

METHODS

A systematic review and meta-analysis of studies published before August 2022 was conducted using the PubMed, Science Direct, Cochrane, and Directory of Open Access Journal (DOAJ) databases. The review included studies that assessed the incidence of DGF following LDKT, and examined its risk factors, while excluding studies involving deceased donors. Potential risk factors were analyzed using pooled mean differences or odds ratios with 95% confidence intervals (CIs). Review Manager 5.3 was used for the meta-analysis.

RESULTS

Among the 13 included studies, 3685 cases of DGF were identified in a total of 113,261 patients (3.25%). Potential risk factors for DGF following LDKT were examined across several aspects, including donor, recipient, donor/recipient relationship, and immunological and intraoperative factors. The identified risk factors included older donors (P = 0.07), male recipients (P < 0.0001), higher recipient body mass index (BMI) (P < 0.0001), non-white recipients (P < 0.0001), pre-existing diabetes (P < 0.0001), pre-existing hypertension (P = 0.01), history of dialysis (P < 0.0001), re-transplantation (P = 0.004), unrelated donor/recipient (P = 0.02), ABO incompatibility (P < 0.0001), higher panel reactive antibody (PRA) levels (P < 0.0001), utilization of right kidney (P < 0.0001), and longer cold ischemia time (CIT) (P = 0.004).

CONCLUSION

Several factors related to the donor, recipient, donor/recipient relationship, and immunological and intraoperative aspects were identified as potential risk factors for the development of DGF following LDKT. Addressing and optimizing these factors may improve the long-term outcomes of LDKT.

Sleep Disorders and Dementia Risk in Older Patients with Kidney Failure: A Retrospective Cohort Study

Key Points

Older patients with kidney failure who are newly diagnosed with sleep disorders are at higher risk of developing any type of dementia, vascular dementia, and other/mixed types of dementia. For older patients with kidney failure who are diagnosed with obstructive sleep apnea, positive airway pressure therapy is an intervention that is associated with lower dementia risk.

Background

Community-dwelling older adults with sleep disorders are at higher risk of developing dementia. Greater than 50% of older patients with kidney failure experience sleep disorders, which may explain their high burden of dementia.

Methods

Among 216,158 patients (aged 66 years and older) with kidney failure (United States Renal Data System; 2008–2019), we estimated the risk of dementia (including subtypes) associated with sleep disorders using Cox proportional hazards models with propensity score weighting. We tested whether positive airway pressure (PAP) therapy was associated with reduced dementia risk among patients with obstructive sleep apnea (OSA).

Results

26.3% of patients were diagnosed with sleep disorders; these patients had a higher 5-year unadjusted cumulative incidence for any type of dementia (36.2% versus 32.3%; P < 0.001), vascular dementia (4.4% versus 3.7%; P < 0.001), and other/mixed dementia (29.3% versus 25.8%; P < 0.001). Higher risk of any type of dementia was identified in patients with insomnia (adjusted hazard ratio [aHR], 1.42; 95% confidence interval [CI], 1.34 to 1.51), sleep-related breathing disorders (SRBDs) (aHR, 1.20, 95% CI, 1.17 to 1.23), and other sleep disorders (aHR, 1.24; 95% CI, 1.11 to 1.39). Higher vascular dementia risk was observed in patients with insomnia (aHR, 1.43; 95% CI, 1.19 to 1.73) and SRBDs (aHR, 1.15; 95% CI, 1.07 to 1.24). Patients with SRBDs (aHR, 1.07; 95% CI, 1.00 to 1.15) were at higher risk of Alzheimer disease. Among patients with OSA, PAP therapy was associated with lower risk of any type of dementia (aHR, 0.82; 95% CI, 0.76 to 0.90) and vascular dementia (aHR, 0.65; 95% CI, 0.50 to 0.85).

Conclusions

Older patients with kidney failure and sleep disorders are at a higher risk of dementia. Sleep is an important modifiable factor that should be considered for targeted interventions to mitigate dementia risk in patients with kidney failure. For patients with OSA, PAP therapy is associated with lower dementia risk.

Evaluating the safety of bariatric surgery as a bridge to kidney transplant: a retrospective cohort study

BACKGROUND

Bariatric surgery has been proven safe in end-stage kidney disease (ESKD); however, few studies have evaluated whether a history of bariatric surgery impacts transplant-specific outcomes. We hypothesize that a history of bariatric surgery at the time of transplant does not adversely impact transplant-specific outcomes.

METHODS

The IBM MarketScan Commercial Claims and Encounters database was queried for patients with a history of kidney transplant between 2000 and 2021. Patients were stratified into three groups based on bariatric surgery status and body mass index (BMI) at the time of transplant: patients with obesity (O), patients without obesity (NO), and patients with a history of bariatric surgery (BS). Inverse probability of treatment weighting was used to control for confounding. Adjusted hazard ratios (aHRs) describing the risk of transplant-specific and postoperative outcomes were estimated using weighted Kaplan-Meier curves. Primary outcomes included 30-day and 1-year risk of transplant-specific outcomes. Secondary outcomes included 30-day and 1-year postoperative complications and 30-day and 1-year risk of wound-related complications.

RESULTS

We identified 14,806 patients; 128 in the BS group, 1572 in the O group, and 13,106 in the NO group. There was no difference in 30-day or 1-year risk of transplant-specific complications between the BS and NO group or the O and NO group. Patients with obesity (O) were more likely to experience wound infection (aHR 1.49, 95% CI 1.12-1.99), wound dehiscence (aHR 2.2, 95% CI 1.5-3.2), and minor reoperation (aHR 1.52, 95% CI 1.23-1.89) at 1 year. BS patients had increased risk of wound infection at 1 year (aHR 2.79, 95% CI 1.26-6.16), but were without increase in risk of minor or major reoperation.

CONCLUSION

A history of bariatric surgery does not adversely affect transplant-specific outcomes after kidney transplant. Bariatric surgery can be safely utilized to improve the transplant candidacy of patients with obesity with CKD and ESKD.

Abdominal computed tomography measurements of body composition and waitlist mortality in kidney transplant candidates

Body mass index is often used to determine kidney transplant (KT) candidacy. However, this measure of body composition (BC) has several limitations, including the inability to accurately capture dry weight. Objective computed tomography (CT)-based measures may improve pre-KT risk stratification and capture physiological aging more accurately. We quantified the association between CT-based BC measurements and waitlist mortality in a retrospective study of 828 KT candidates (2010-2022) with clinically obtained CT scans using adjusted competing risk regression. In total, 42.5% of candidates had myopenia, 11.4% had myopenic obesity (MO), 68.8% had myosteatosis, 24.8% had sarcopenia (probable = 11.2%, confirmed = 10.5%, and severe = 3.1%), and 8.6% had sarcopenic obesity. Myopenia, MO, and sarcopenic obesity were not associated with mortality. Patients with myosteatosis (adjusted subhazard ratio [aSHR] = 1.62, 95% confidence interval [CI]: 1.07-2.45; after confounder adjustment) or sarcopenia (probable: aSHR = 1.78, 95% CI: 1.10-2.88; confirmed: aSHR = 1.68, 95% CI: 1.01-2.82; and severe: aSHR = 2.51, 95% CI: 1.12-5.66; after full adjustment) were at increased risk of mortality. When stratified by age, MO (aSHR = 2.21, 95% CI: 1.28-3.83; P interaction = .005) and myosteatosis (aSHR = 1.95, 95% CI: 1.18-3.21; P interaction = .038) were associated with elevated risk only among candidates <65 years. MO was only associated with waitlist mortality among frail candidates (adjusted hazard ratio = 2.54, 95% CI: 1.28-5.05; P interaction = .021). Transplant centers should consider using BC metrics in addition to body mass index when a CT scan is available to improve pre-KT risk stratification at KT evaluation.

Exploration of wound-related complications post-kidney transplantation

An essential intervention for patients with end-stage renal disease is kidney transplantation. Nonetheless, patient outcomes are substantially affected by complications associated with postoperative wounds. The purpose of this research was to determine the prevalence, risk factors and repercussions of wound-related complications among kidney transplant recipients. A cross-sectional observational study was undertaken at Qilu Hospital of Shandong University Department of Organ Transplantation, China. Included in the study were 118 patients who had undergone kidney transplantation during the specified time period. Medical record evaluations, questionnaires and patient interviews were utilized to collect data, with an emphasis on demographics, transplant information, postoperative care and wound complications. Infection, dehiscence, lymphocoele, delayed wound healing, seroma formation and haematoma were classified as complications. The presence of comorbidities, age over 50 and living donor transplants were identified as significant risk factors for postoperative complications. The most prevalent complications observed were delayed wound healing (21.2%) and infections (16.9%) (p < 0.05). Antibiotics were found to be effective in managing infections, while prolonged conservative management was necessary for delayed wound healing. Prominent complications that recurred were infections and wound healing delays. No statistically significant correlation was observed between gender, BMI and prior transplants with the occurrence of complications (p > 0.05). The research highlighted the significance of taking into account patient-specific variables, including age and concurrent medical conditions, when conducting post-kidney transplantation treatment. The results supported the use of individualized strategies in postoperative care, particularly for populations at high risk, in order to reduce the incidence and severity of complications associated with wounds in pursuit to enhancing clinical practices and formulating focused intervention strategies to improve patient outcomes following transplantation.

Stratification of Kidney Transplant Recipients Into Five Subgroups Based on Temporal Disease Trajectories

Background

Kidney transplantation is the treatment of choice for patients with end-stage renal disease. Considerable clinical research has focused on improving graft survival and an increasing number of kidney recipients die with a functioning graft. There is a need to improve patient survival and to better understand the individualized risk of comorbidities and complications. Here, we developed a method to stratify recipients into similar subgroups based on previous comorbidities and subsequently identify complications and for a subpopulation, laboratory test values associated with survival.

Methods

First, we identified significant disease patterns based on all hospital diagnoses from the Danish National Patient Registry for 5752 kidney transplant recipients from 1977 to 2018. Using hierarchical clustering, these longitudinal patterns of diseases segregate into 3 main clusters of glomerulonephritis, hypertension, and diabetes. As some recipients are diagnosed with diseases from >1 cluster, recipients are further stratified into 5 more fine-grained trajectory subgroups for which survival, stratified complication patterns as well as laboratory test values are analyzed.

Results

The study replicated known associations indicating that diabetes and low levels of albumin are associated with worse survival when investigating all recipients. However, stratification of recipients by trajectory subgroup showed additional associations. For recipients with glomerulonephritis, higher levels of basophils are significantly associated with poor survival, and these patients are more often diagnosed with bacterial infections. Additional associations were also found.

Conclusions

This study demonstrates that disease trajectories can confirm known comorbidities and furthermore stratify kidney transplant recipients into clinical subgroups in which we can characterize stratified risk factors. We hope to motivate future studies to stratify recipients into more fine-grained, homogenous subgroups to better discover associations relevant for the individual patient and thereby enable more personalized disease-management and improve long-term outcomes and survival.

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.

Nutritional Considerations for Patients With Renal Failure Undergoing Sleeve Gastrectomy

Obesity is highly prevalent in patients with renal disease, as it contributes to or accelerates the progression of kidney disease and is frequently a barrier to kidney transplantation. Patients with renal disease have unique dietary needs due to various metabolic disturbances resulting from altered processing and clearance of nutrients. They also frequently present with physical disability, resulting in difficulty achieving adequate weight loss through lifestyle modifications. Therefore, kidney transplant candidates may benefit from bariatric surgery, particularly sleeve gastrectomy (SG), as the safest, most effective, and long-lasting weight loss option to improve comorbidities and access to transplantation. However, concerns regarding nutritional risks prevent broader dissemination of SG in this population. No specific guidelines tailored to the nutritional needs of patients with renal disease undergoing SG have been developed. Moreover, appropriate monitoring strategies and interventions for muscle loss and functional status preservation, a major concern in this at-risk population, are unknown. We aimed to summarize the available literature on the nutritional requirements of patients with renal disease seeking SG as a bridge to transplantation. We also provide insight and guidance into the nutritional management pre and post-SG.

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.

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.

Effect of glycopyrrolate on the postoperative urine output of patients following kidney transplantation: a retrospective observational study

OBJECTIVES

To compare the urine output and estimated glomerular filtration rate (eGFR) of patients postoperatively administered sugammadex or glycopyrrolate 7 days following kidney transplantation (KT).

METHODS

We retrospectively enrolled 134 consecutive patients who underwent KT under general anesthesia. Their urine output and eGFR were recorded every 24 hours between postoperative day (POD) 1 and 7. We used regression analysis to evaluate the relationship between the reversal agent administered and the outcomes of the participants.

RESULTS

The urine output and eGFR of the participants did not differ between the two groups. Multivariate analysis showed that body mass index (BMI) (odds ratio (OR) 1.21; 95% confidence interval (CI) 1.05-1.40), diabetes mellitus (OR 3.14; 95% CI 1.07-9.16), neurovascular disease (OR 7.00; 95% CI 1.61-30.42), and the duration of surgery (OR 1.01; 95% CI 1.00-1.01) were associated with lower urine output on POD 7. In addition, only BMI (OR 1.25; 95% CI 1.09-1.42) was associated with low eGFR on POD 7.

CONCLUSIONS

The urine output and eGFR of patients administered sugammadex or glycopyrrolate following KT did not differ 7 days later. Moreover, glycopyrrolate does not affect urine output or eGFR on POD 7, according to multivariate regression analysis.

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.

The association of center volume with transplant outcomes in selected high-risk groups in kidney transplantation

BACKGROUND

In context of increasing complexity and risk of deceased kidney donors and transplant recipients, the impact of center volume (CV) on the outcomes of high-risk kidney transplants(KT) has not been well determined.

METHODS

We examined the association of CV and outcomes among 285 U.S. transplant centers from 2000-2016. High-risk KT were defined as recipient age ≥ 70 years, body mass index (BMI) ≥ 35 kg/m², receiving kidneys from donors with kidney donor profile index(KDPI) ≥ 85%, acute kidney injury(AKI), hepatitisC + . Average annual CV for the specific-high-risk KT categorized in tertiles. Death-Censored-Graft-Loss(DCGL) and death at 3 months, 1, 5, and 10 years were compared between CV tertiles using Cox-regression models.

RESULTS

Two hundred fifty thousand five hundred seventy-four KT were analyzed. Compared to high CV, recipients with BMI ≥ 35 kg/m² had higher risk of DCGL in low CV(aHR = 1.11,95%CI = 1.03-1.19) at 10 years; recipients with age ≥ 70 years had higher risk of death in low CV(aHR = 1.07,95%CI = 1.01-14) at 10 years. There was no difference of DCGL or death in low CV for donors with KDPI ≥ 85%, hepatitisC + , or AKI.

CONCLUSIONS

Recipients of high-risk KT with BMI ≥ 35 kg/m² have higher risk of DCGL and recipients age ≥ 70 years have higher risk of death in low CV, compared to high CV. Future studies should identify care practices associated with CV that support optimal outcomes after KT.

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.

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.

The Predictive Value of Donor Renal Functions, Graft Weight, Recipient Body Mass Index, and Human Leucocyte Antigen Match Regarding Early Graft Functions

Background and objective Graft performance is the most important postoperative parameter for patients undergoing kidney transplantation (KTx). The renal function of the donor is reported to be correlated with graft function after KTx. The body mass index (BMI) is also one of the important parameters involved in the prediction of graft function. The aim of this retrospective study was to examine the relationship between early postoperative graft function in patients undergoing KTx and donor cystatin C and estimated glomerular filtration rate (e-GFR) levels, graft weight/recipient BMI (G/B) ratio, and human leukocyte antigen (HLA) tissue compatibility. Materials and methods A total of 215 cases (215 donors, 215 recipients) who underwent KTx at our center between January 2018 and December 2022 were included in the study. Patients' age, sex, BMI, preoperative donor serum cystatin C and e-GFR levels, HLA tissue compatibility, graft weights, and recipient creatinine levels were recorded one week postoperatively. The Kolmogorov-Smirnov test and histogram plots were used to analyze the conformity of the variables to the normal distribution and Spearman's correlation test was used to analyze the relationship between variables. Results A negative correlation was identified between recipient creatinine level and G/B ratio and donor e-GFR (r = -0.256 and -0.137, respectively). Donor cystatin C level showed a positive correlation with recipient creatinine level (r = 0.242). No significant correlation was noted in terms of tissue matching rates (p = 0.616). Conclusion Although these three parameters are correlated with early graft functions, the graft weight/recipient BMI ratio has the strongest correlation.

Obesity and Kidney Transplant Candidates: An Outcome Analysis Based on Body Mass Index

Background Obesity is a well-established risk factor for a decline in renal function and post-operative complications. Also, obese patients suffer worse outcomes such as higher rates of wound complications, longer hospital stays, and delayed graft function (DGF) when compared to nonobese patients. The correlation between having a high BMI and the postoperative outcomes of kidney transplantation has not been investigated yet in Saudi Arabia. There is scarce evidence that patients with obesity who have undergone kidney transplantation are devoid of any complications before, during, or after their procedure. Methodology A retrospective cross-sectional study was conducted using charts of nearly 142 patients in King Abdullah Specialist Children's Hospital in Riyadh, who had kidney transplant surgery in the organ transplantation department. All Obese patients with BMI >29.9 who underwent Kidney Transplant Surgery in King Abdulaziz Medical City from 2015 to 2022 were used. Details of hospital admissions were retrieved. Results A total of 142 patients fulfilling the inclusion criteria were included. There was a significant difference between patients regarding pre-surgical history where all cases (100%; 2) with class three obesity were hypertensive and on dialysis versus (77.8%; 21) and (70.4%; 19) of class two obesity and (86.7%; 98) and (78.8%; 89) of class one obesity cases, respectively (P = 0.041). Regarding medical history, hypertension was reported among 121 (85%), followed by dialysis (77%; 110), diabetes mellitus (DM) (52%; 74), dyslipidemia (24%; 35), endocrine diseases (15%; 22), and cardiovascular diseases (16%; 23). Considering post-transplant complications, 14.1% (20) of the study cases had DM (16.8% of obese class one, 3.7% of obese class two, and none of obese class three; P = 0.996) and urinary tract infection (UTI) among 7% (10) of the cases (6.2% of obese class one, 11.1% of obese class two, and none of obese class three; P = 0.996). All these differences according to patients' BMI were statistically insignificant. Conclusion Obese patients are more likely to experience difficult intraoperative management along with a complicated postoperative course due to numerous concomitant comorbidities. Post-transplant DM (PTDM) was the most prominent post-transplant complication followed by UTI. A remarkable reduction in serum creatinine and blood urea nitrogen (BUN) has been observed at the time of discharge and after six months compared to pre-transplant measurements.

Analysis of individual components of frailty: Pre-transplant grip strength is the strongest predictor of post kidney transplant outcomes

Frailty is commonly assessed during kidney transplant recipient (KTR) evaluation. However, individual frailty components may have varying impact on post-transplant outcomes. In this single-center study of 825 KTRs, we determined the association between the individual components of a modified Fried frailty score and delayed graft function (DGF), early hospital readmission (EHR), cardiovascular (CV) events, acute rejection (AR), death censored graft failure (DCGF), and death. Sum frailty ≥3 was significantly associated with EHR (aOR = 3.62; 95% CI: 1.21-10.80). Among individual components, only grip strength was significantly associated with EHR (aOR = 1.54; 95% CI: 1.03-2.31). The addition of grip strength to a model with the other four components resulted in Net Reclassification Improvement (NRI) of 20.51% (p = .01). Similarly, only grip strength was significantly associated with CV events (aOR = 1.79; 95% CI: 1.12-2.86). The addition of grip strength to a model with the other four components resulted in NRI of 27.37% (p = .006). No other frailty components were associated with the outcomes of interest. Based on our findings, handgrip strength may be an important tool while assessing frailty, mainly predicting early readmission and cardiovascular events post-transplant.

Analysis of Risk Factors for Delayed Graft Function After Kidney Transplantation

BACKGROUND

Delayed graft function (DGF) is a serious complication associated with worsening outcomes in kidney transplantation. To facilitate DGF risk reduction, this study aimed to identify the incidence and modifiable risk factors of this condition in kidney transplant patients.

METHODS

This retrospective chart review included 220 patients who underwent kidney transplants between 2012 and 2021 at our kidney transplant center. Delayed graft function was defined as the requirement of hemodialysis within a week of transplantation. Clinical data from patients with DGF and those without this condition were compared to identify risk factors of DGF.

RESULTS

Of 205 eligible patients, 20 (9.76%) developed DGF. In the univariate analysis, high hemoglobin level, deceased-donor type, and longer warm and cold ischemic times were significantly associated with DGF (P < .05). In the variable selection in logistic regression analysis, high hemoglobin level, with a cutoff value of 11.35 g/dL, and deceased-donor transplants were associated with higher DGF incidence (P < .05 for both factors).

CONCLUSIONS

Our findings newly demonstrated that DGF occurred more frequently in patients with hemoglobin level >11.35 g/dL. As such, improvement in kidney transplantation outcomes could be achieved by reducing this modifiable risk factor.

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.

Recipient obesity as a risk factor in kidney transplantation

BACKGROUND

The aim of the study was to investigate the effect of recipient obesity on the short- and long-term outcomes of patients undergoing primary kidney transplantation (KT).

PATIENTS AND METHODS

A total of 578 patients receiving primary KT in our department between 1993 and 2017 were included in the study. Patients were divided according to their body mass index (BMI) into normal weight (BMI 18.5-24.9 kg/m2; N = 304), overweight (BMI 25-29.9 kg/m2; N = 205) and obese (BMI ≥ 30 kg/m2; N = 69) groups. Their clinicopathological characteristics, outcomes, and survival rates were analyzed retrospectively.

RESULTS

Obesity was associated with an increased rate of surgical complications such as wound infection (P < 0.001), fascial dehiscence (P = 0.023), and lymphoceles (P = 0.010). Furthermore, the hospital stay duration was significantly longer in the groups with obese patients compared to normal weight and overweight patients (normal weight: 22 days, overweight: 25 days, and obese: 33 days, respectively; P < 0.001). Multivariate analysis showed that recipient obesity (BMI ≥ 30) was an independent prognostic factor for delayed graft function (DGF) (OR 2.400; 95% CI, 1.365-4.219; P = 0.002) and postoperative surgical complications (OR 2.514; 95% CI, 1.230-5.136; P = 0.011). The mean death-censored graft survival was significantly lower in obese patients (normal weight: 16.3 ± 0.6 years, overweight: 16.3 ± 0.8 years, obese 10.8 ± 1.5 years, respectively; P = 0.001). However, when using the Cox proportional hazards model, the association between recipient obesity and death-censored renal graft failure disappeared, after adjustment for important covariates, whereas the principal independent predictors of graft loss were recipient diabetes mellitus and hypertension and kidneys from donors with expanded donor criteria.

CONCLUSION

In conclusion, obesity increases the risk of DGF and post-operative surgical complications after primary KT. Appropriate risk-adapted information concerning this must be provided to such patients before KT. Furthermore, obesity-typical concomitant diseases seem to negatively influence graft survival and need to be considered after the transplantation of obese patients.

Nonlinear relationship between body mass index and clinical outcomes after kidney transplantation: A dose-response meta-analysis of 50 observational studies

BACKGROUND

Exact dose-response relationship between body mass index at transplantation and clinical outcomes after kidney transplantation remained unclear, and no specific body mass index threshold and pretransplant weight loss aim were recommended for kidney transplantation candidates among transplant centers.

METHODS

PubMed, Embase, Web of Science, and Cochrane Library were searched for literature published up to December 31, 2019. The two-stage, random effect meta-analysis was performed to estimate the dose-response relationship between body mass index and clinical outcomes after kidney transplantation.

RESULTS

Ninety-four studies were included for qualitative assessment and 50 for dose-response meta-analyses. There was a U-shaped relationship between graft loss, patient death, and body mass index. Body mass index with the lowest risk of graft loss was 25.2 kg/m², and preferred body mass index range was 22-28 kg/m². Referring to a body mass index of 22 kg/m², the risk of graft loss was 1.088, 0.981, 1.003, and 1.685 for a body mass index of 18, 24, 28, and 40 kg/m², respectively. Body mass index with the lowest risk of patient death was 24.7 kg/m², and preferred body mass index range was 22-27 kg/m². Referring to a body mass index of 22 kg/m², the patient death risk was 1.115, 0.981, 1.032, and 2.634 for a body mass index of 18, 24, 28, and 40 kg/m², respectively. J-shaped relationships were observed between body mass index and acute rejection, delayed graft function, primary graft nonfunction, and de novo diabetes. Pair-wise comparisons showed that higher body mass index was also a risk factor for cardiovascular diseases, hypertension, infection, longer length of hospital stay, and lower estimated glomerular filtration rate level.

CONCLUSION

Underweight and severe obesity at transplantation are associated with a significantly increased risk of graft loss and patient death. A target body mass index at kidney transplantation is 22-27 kg/m².

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.

Deep Learning-Based Quantification of Visceral Fat Volumes Predicts Posttransplant Diabetes Mellitus in Kidney Transplant Recipients

Background: Because obesity is associated with the risk of posttransplant diabetes mellitus (PTDM), the precise estimation of visceral fat mass before transplantation may be helpful. Herein, we addressed whether a deep-learning based volumetric fat quantification on pretransplant computed tomographic images predicted the risk of PTDM more precisely than body mass index (BMI).

Methods: We retrospectively included a total of 718 nondiabetic kidney recipients who underwent pretransplant abdominal computed tomography. The 2D (waist) and 3D (waist or abdominal) volumes of visceral, subcutaneous, and total fat masses were automatically quantified using the deep neural network. The predictability of the PTDM risk was estimated using a multivariate Cox model and compared among the fat parameters using the areas under the receiver operating characteristic curves (AUROCs).

Results: PTDM occurred in 179 patients (24.9%) during the median follow-up period of 5 years (interquartile range, 2.5–8.6 years). All the fat parameters predicted the risk of PTDM, but the visceral and total fat volumes from 2D and 3D evaluations had higher AUROC values than BMI did, and the best predictor of PTDM was the 3D abdominal visceral fat volumes [AUROC, 0.688 (0.636–0.741)]. The addition of the 3D abdominal VF volume to the model with clinical risk factors increased the predictability of PTDM, but BMI did not.

Conclusions: A deep-learning based quantification of visceral fat volumes on computed tomographic images better predicts the risk of PTDM after kidney transplantation than BMI.

Incidence Rate and Predictors of Delayed Graft Function Among Adult Kidney Transplant Recipients at a Tertiary Care Hospital in Riyadh, Saudi Arabia

Background

Delayed graft function (DGF) is the most common early postoperative complication of renal transplantation. The occurrence of DGF can lead to both early and late devastating consequences on the allograft’s survival. The risk of developing this complication can increase with certain factors that are related to both the donor and the recipient. In the present study, we aimed to detect the incidence rate of DGF among patients attending a tertiary care hospital in Riyadh, Saudi Arabia, and to investigate potential predictors of DGF.

Materials and methods

This retrospective chart review was conducted at King Abdulaziz Medical City (KAMC), a tertiary care hospital in Riyadh, Saudi Arabia. The inclusion criteria were all patients, 18 years or older, who had renal transplantation from January 1, 2016, to March 31, 2020. Patients who had a second renal transplant, or renal transplantation in a different hospital and were followed up at KAMC were excluded. Patients’ medical records were accessed using the BESTCare electronic system to obtain the patients’ demographic data. A Chi-square test was used to test for the association between a predictor and a delay in graft function.

Results

A total of 344 patients were enrolled in the present study, approximately half of whom were males (56.6%, n=189). Around one-half (49.4%) were aged between 40 and 64 years. The most common cause of renal failure was hypertension, which was found in 117 (35%) patients, followed by diabetes mellitus (DM) in 94 (28.1%) patients. Most organ donors 258 (77.2%) were alive. A total of 23 (6.9%) participants developed DGF. Mycophenolate mofetil (MMF) was found to be significantly associated with DGF (P < 0.001). Those who took MMF (5.9%) had a significantly lower rate of DGF compared to those who did not (36.4%). A significantly higher rate of DGF was seen in patients whose transplants were taken from deceased donors (15.5%) compared to living donor transplants (3.9%). Gender, age, body mass index (BMI), recipient blood type, donor blood type, and cause of renal failure were not associated with DGF.

Conclusions

Only 6.9% of the study’s participants exhibited DGF. The observed rate was lower than the ones detected in the literature. Those who took MMF had a significantly lower rate of DGF compared to those who did not. Transplants of deceased donors (15.5%) showed a significantly higher rate of DGF. Larger multicenter studies are required to further investigate DGF in a region with a high prevalence of organ failure and a higher need for transplantations, such as Saudi Arabia.

Recipient Obesity and Kidney Transplant Outcomes: A Mate-Kidney Analysis

RATIONALE & OBJECTIVE

The impact of extreme recipient obesity on long-term kidney transplant outcomes has been controversial. This study sought to evaluate the association of various levels of recipient obesity on kidney transplantation outcomes by comparing mate-kidney recipient pairs to address possible confounding effects of donor characteristics on posttransplant outcomes.

STUDY DESIGN

Nationwide observational cohort study using mate-kidney models.

SETTING & PARTICIPANTS

In analysis based on the Organ Procurement and Transplant Network/United Network of Organ Sharing database, 44,560 adult recipients of first-time deceased-donor kidney transplants from 2001 through 2016 were paired by donor.

PREDICTORS

Recipient body mass index (BMI) categorized as 18-25 (n = 12,446), >25-30 (n = 15,477), >30-35 (n = 11,144; obese), and >35 (n = 5,493; extreme obesity) kg/m².

OUTCOMES

Outcomes included patient survival, graft survival, death-censored graft survival, delayed graft function (DGF), and hospital length of stay.

ANALYTICAL APPROACH

Conditional logistic regression and stratified proportional hazards models were used to compare outcomes as odds ratios and hazard ratios (HRs), adjusted for recipient and transplant factors, using recipients with a BMI >35 kg/m² as a reference.

RESULTS

At a median follow-up of 3.9 years, adjusted odds ratios for DGF were 0.42 (95% CI, 0.36-0.48), 0.55 (95% CI, 0.48-0.62), and 0.73 (95% CI, 0.64-0.83) for BMI 18-25, >25-30, and >30-35 kg/m², respectively (P < 0.001 for all). Death-censored graft failure was less frequent for BMI ≤25 and >25-30 kg/m² (HRs of 0.66 [95% CI, 0.59-0.74] and 0.79 [95% CI, 0.70-0.88], respectively; P < 0.001 for both), but not for BMI >30-35 kg/m² (HR, 0.91 [95% CI, 0.81-1.02]; P = 0.09). Length of stay and patient survival did not differ by recipient BMI.

LIMITATIONS

Observational study with limited detail regarding potential confounders.

CONCLUSIONS

Despite an increased risk of DGF likely unrelated to donor organ quality, long-term transplant outcomes among recipients with a BMI >35 kg/m² are similar to those among recipients with a BMI >30-35 kg/m², supporting a flexible approach to kidney transplantation candidacy in candidates with extreme obesity.

Renal transplantation outcomes in obese patients: a French cohort-based study

Background

Whilst there are a number of publications comparing the relationship between body mass index (BMI) of kidney transplant recipients and graft/patient survival, no study has assessed this for a French patient cohort.

Methods

In this study, cause-specific Cox models were used to study patient and graft survival and several other time-to-event measures. Logistic regressions were performed to study surgical complications at 30 days post-transplantation as well as delayed graft function.

Results

Among the 4691 included patients, 747 patients were considered obese with a BMI level greater than 30 kg/m². We observed a higher mortality for obese recipients (HR = 1.37, p = 0.0086) and higher risks of serious bacterial infections (HR = 1.24, p = 0.0006) and cardiac complications (HR = 1.45, p < 0.0001). We observed a trend towards death censored graft survival (HR = 1.22, p = 0.0666) and no significant increased risk of early surgical complications.

Conclusions

We showed that obesity increased the risk of death and serious bacterial infections and cardiac complications in obese French kidney transplant recipients. Further epidemiologic studies aiming to compare obese recipients versus obese candidates remaining on dialysis are needed to improve the guidelines for obese patient transplant allocation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02278-1.

Obesity, Chronic Kidney Disease, and Kidney Transplantation: An Evolving Relationship

Obesity has a fundamental role in driving the global kidney disease burden. The perplexing relationship of obesity with chronic kidney disease remains debated. However, a thorough understanding of the interplay of obesity in conjunction with chronic kidney disease and appropriate management options is lacking, leading to further increases in morbidity and mortality. Moreover, underutilization of bariatric procedures and unrealistic expectations of weight reduction based on body mass index, leading to poor access to kidney transplantation, are fueling the fire. In this review, we summarize the available data related to the obesity and chronic kidney disease association and its novel management options.

Risk factors for delayed graft function and their impact on graft outcomes in live donor kidney transplantation

BACKGROUND

Delayed graft function (DGF) is a manifestation of acute kidney injury uniquely framed within the transplant process and a predictor of poor long-term graft function1. It is less common in the setting of living donor (LD) kidney transplantation. However, the detrimental impact of DGF on graft survival is more pronounced in LD2.

PURPOSE

To study the effects of DGF in the setting of LD kidney transplantation.

METHODS

We performed a retrospective analysis of LD kidney transplantations performed between 2010 and 2018 in the UNOS/OPTN database for DGF and its effect on graft survival.

RESULTS

A total of 42,736 LD recipients were identified, of whom 1115 (2.6%) developed DGF. Recipient dialysis status, male gender, diabetes, end-stage renal disease, donor age, right donor nephrectomy, panel reactive antibodies, HLA mismatch, and cold ischemia time were independent predictors of DGF. Three-year graft survival in patients with and without DGF was 89% and 95%, respectively. DGF was the greatest predictor of graft failure at three years (hazard ratio = 1.766, 95% CI: 1.514-2.059, P = 0.001) and was associated with higher rates of rejection (9% vs. 6.28%, P = 0.0003). Among patients with DGF, the graft survival rates with and without rejection were not different.

CONCLUSION

DGF is a major determinant of poor graft functional outcomes, independent of rejection.

Novel approaches to sarcopenic obesity and weight management before and after kidney transplantation

PURPOSE OF REVIEW

Although a widely recognized and complex pathophysiological condition, sarcopenic obesity remains less appreciated and may elude diagnosis and workup in both kidney transplant waitlisted candidates and kidney transplant recipients. The lack of consensus definition, and practical diagnostic tools for evaluating waitlisted candidates and transplant recipients are barriers to early detect and initiate therapeutic management for sarcopenic obesity. Although sarcopenia leads to poor clinical outcomes, posttransplant obesity yields conflicting results. Exercise and nutritional managements are common therapies for sarcopenic obese patients; however, surgery weight loss or bariatric surgery in both transplant candidates and potential living kidney donors shows promising benefits for kidney transplant access in waitlist obese candidates but may require to be selected for appropriate patients.

RECENT FINDINGS

Pathogenesis and management for sarcopenia and obesity are interconnected. The benefits of exercise to improve muscle mass and function is clear in waitlist kidney transplant candidates and transplant recipients. However, there are several barriers for those to increase exercise and improve physical activity including patient, provider, and healthcare or environmental factors. The advantages of fat mass reduction to lose weight can promote muscle mass and strength. However, epidemiological data regarding the obesity paradox in dialysis-dependent patients when overnutrition provides survival benefits for this population should be taken into account when performing weight loss especially bariatric surgery.

SUMMARY

Barriers in providing optimal care to kidney transplant waitlisted candidates and transplant recipients may partly result from underdiagnosis of sarcopenic obesity; notwithstanding that this entity has increasingly been more recognized. Mechanistic studies to better understand pathogenesis of sarcopenic obesity will help determine pathogenesis and clinical tools for diagnosis of this entity, which can facilitate further studies related to the outcomes and weight management to ultimately improve kidney transplant outcomes.

Bariatric surgery before and after kidney transplantation: long-term weight loss and allograft outcomes

BACKGROUND

Severe obesity is frequently a barrier to kidney transplantation, and kidney transplant recipients often have significant weight gain following transplantation.

OBJECTIVES

The goals of this study were to evaluate the long-term risks and benefits of bariatric surgery before and after kidney transplantation.

SETTING

University Hospital, United States.

METHODS

We performed a retrospective cohort study of 43 patients who had pretransplantation bariatric surgery and 21 patients who had posttransplantation bariatric surgery from 1994 to 2017 with propensity-score matching to identify matched controls using national registry data.

RESULTS

Body mass index at the time of transplantation was similar in patients who underwent bariatric surgery before versus after transplantation (32 versus 34 kg/m², P = .172). There was no significant difference in body mass index in the 5 years after bariatric surgery among patients who underwent bariatric surgery before versus after kidney transplantation (36 versus 32 kg/m², P = 0.814). Compared with matched controls, bariatric surgery before (n = 38) and after (n = 18) kidney transplantation was associated with a decreased risk of allograft failure (hazard ratio .31 [95% confidence interval .29-0.33] and .85 [95% confidence interval .85-.86] for pre- and posttransplant, respectively) and mortality (hazard ratio .57 [95% confidence interval .53-.61] and .80 [95% confidence interval .79-.82] for pre- and posttransplant, respectively).

CONCLUSIONS

Bariatric surgery before and after kidney transplantation results in similar maintenance of weight loss and improved long-term allograft survival compared with matched controls. Bariatric surgery appears to be a safe and reasonable approach to weight loss both before and after transplantation.

Impact of obesity on dialysis and transplant and its management

Obesity is increasing to unprecedented levels, including in the end-stage kidney disease population, where upwards of 60% of kidney transplant patients are overweight or obese. Obesity poses additional challenges to the care of the dialysis patient, including difficulties in creating vascular access and inserting Tenckhoff catheters, higher rates of catheter malfunction and peritonitis, the need for longer and/or more frequent dialysis (or peritoneal dialysis [PD] exchanges) to achieve adequate clearance, increased metabolic complications particularly with PD, and obesity is a barrier to kidney transplantation. In this article, we review special considerations in performing PD, hemodialysis and transplant in the obese patient, as well as the evidence behind medical and surgical management of obesity in dialysis patients.

Long-term outcomes in patients with obesity and renal disease after sleeve gastrectomy

Morbid obesity is a barrier to kidney transplant in patients with end-stage renal disease (ESRD). Laparoscopic sleeve gastrectomy (SG) is an increasingly considered intervention, but the safety and long-term outcomes are uncertain. We reviewed prospectively collected data on patients with ESRD and chronic kidney disease (CKD) undergoing SG from 2011 to 2018. There were 198 patients with ESRD and 45 patients with CKD (stages 1-4) who met National Institutes of Health guidelines for bariatric surgery and underwent SG; 72% and 48% achieved a body mass index of ≤ 40 and ≤ 35 kg/m² , respectively. The mean percentages of total weight loss and excess weight loss were 18.9 ± 10.8% and 38.2 ± 20.3%, respectively. SG reduced hypertension (85.8% vs 52.1%), decreased antihypertensive medication use (1.6 vs 1.0) (P < .01 each), and reduced incidence of diabetes (59.6% vs 32.5%, P < .01). Of the 71 patients with ESRD who achieved a body mass index of ≤ 40 kg/m² , 45 were waitlisted and received a kidney transplant, whereas 10 remain on the waitlist. Mortality rate after SG was 1.8 per 100 patient-years, compared with 7.3 for non-SG. Patients with stage 3a or 3b CKD exhibited improved glomerular filtration rate (43.5 vs 58.4 mL/min, P = .01). In conclusion, SG safely improves transplant candidacy while providing significant, sustainable effects on weight loss, reducing medical comorbidities, and possibly improving renal function in stage 3 patients.

Efficacy and Safety of Intra-gastric Balloon Placement in Dialyzed Patients Awaiting Kidney Transplantation

BACKGROUND

The number of obese patients who are candidates for renal transplantation has considerably increased, but obesity can be a barrier to kidney transplantation. Weight loss is often difficult through diet alone. We studied the efficacy and tolerance of the intra-gastric balloon (IGB) procedure in obese patients who were undergoing dialysis and were candidates for a renal transplantation.

PATIENTS AND METHODS

Obese patients (BMI > 30 kg/m²) who were candidates for renal transplantation were prospectively included in the study between 2010 and 2012. The balloon was inserted and removed during a gastric endoscopy under general anesthesia. The treatment lasted 6 months. The end point was a decrease in BMI after 6 months. Body impedance spectrometry (BIS) and nutritional statute were evaluated initially and then after IGB removal.

RESULTS

Seventeen patients (nine females and eight males) with a mean age of 53.4 years [19.4-69.4] were included. The decrease in body mass index (BMI) during the 6-month placement was 3 kg/m² (from 37.7 to 34.4 kg/m²). The mean weight loss was 7 kg. The mean percentage of excess weight loss after 6 months was 20.2 (± 11.4). The tolerance was good without any complications. Eleven patients underwent kidney transplantation.

CONCLUSION

IGB in obese dialyzed patients who are candidates for renal transplantation is safe and effective. However, the amount of weight loss can vary.

Regulatory T Cells in the Context of New-Onset Diabetes After Renal Transplant: A Single-Center Experience

BACKGROUND

New-onset diabetes mellitus after transplant (NODAT) is a well-known complication of renal transplant that severely affects graft and patient survival. It is necessary to explore further risk factors and reveal the underlying pathomechanism.

METHODS

Renal transplants performed between January 2010 and June 2018 were involved. Exclusion criteria were the recipient age younger than 18 years, follow-up period less than 6 months, and patients with diabetes at the time of transplant. Only primary kidney transplants were involved in our study, which totaled 223 cases. Besides donor and recipient demographic data, the type of immunosuppression, the average fasting glucose level, and T-subset profiles were compared.

RESULTS

Of 223 cases there were 33 patients (14.8%) with NODAT (17 female; mean age, 54.2 [SD, 10.3] years; mean body mass index [calculated as weight in kilograms divided by height in meters squared], 27.8 [SD, 5.1]; mean follow-up, 43.3 [SD, 25.5] months). The control group consisted of 190 patients. The average fasting blood glucose level was higher in the NODAT group vs the control group (P < .001). The average fasting blood glucose level above diabetic threshold (≥7 mmol/L) was in association with a 6-fold higher risk of NODAT (odds ratio, 5.86; 95% CI, 2.46-13.97; P < .001). Absolute value of CD4⁺CD25^brightCD127^dim regulatory T cells was lower in the NODAT group at the first month after transplant (P = .048) Immunosuppressive protocol and survival data did not differ.

CONCLUSIONS

Intensive management of the carbohydrate excursions during the early post-transplant period may decrease the incidence of NODAT. Further investigations will be required to decide whether the reduced CD4⁺CD25^brightCD127dim/regulatory T-cell count contributes the development of NODAT.

Obesity in Kidney Transplantation: Impact on Transplant Candidates, Recipients, and Donors

Obesity is now common among children and adults who are kidney transplant candidates and recipients. It is associated with an increased risk of cardiovascular disease and kidney failure. This also pertains to potential living kidney donors with obesity. Obese patients with end-stage renal disease benefit from transplantation as do nonobese patients, but obesity is also associated with more risk. A complicating factor is that obesity is also associated with increased survival on maintenance dialysis in adults, but not in children. The assessment of obesity and body habitus should be individualized. Body mass index is a common but imperfect indicator of obesity. The medical management of obesity in renal failure patients is often unsuccessful. Bariatric surgery, specifically laparoscopic sleeve gastrectomy, can result in significant weight loss with reduced morbidity, but many patients do not agree to undergo this treatment. The best approach to manage obese transplant candidates and recipients is yet unresolved.

Survival benefit in bariatric surgery kidney recipients may be mediated through effects on kidney graft function and improvement of co-morbidities: A case-control study

BACKGROUND

Data on the benefits of bariatric surgery for morbid obesity among kidney transplant recipients are scarce.

OBJECTIVE

To examine the effect of bariatric surgery on graft function and survival and on obesity-related co-morbidities.

SETTING

University hospital.

METHODS

This case-control study used retrospectively collected data of all kidney recipients who underwent bariatric surgery in our institution between November 2011 and August 2016 (n = 30, 11 females). Nonbariatric operated kidney recipients matched for age, sex, and time elapsed since transplantation served as controls (n = 50, 23 females). Main outcomes were renal function, graft loss events, mortality, and obesity-related co-morbidities.

RESULTS

The mean follow-up duration was 2.4 ± 1.3 years for both groups. At final follow-up, there was an increase in estimated glomerular filtration rates for the bariatric surgery group, and a decrease for the controls (13.4 ± 19.9 and -3.9 ± 15.8 mL/min/1.73 m², respectively, P < .001). The chronic kidney disease classification improved in 9 bariatric surgery group patients and in 6 controls (P = .1). Two patients in the bariatric surgery group and 6 controls died. Total death or graft function loss during the follow-up was 6.7% and 16.7%, respectively (P = .3). The total numbers of co-morbidities and medications were lower in the bariatric surgery patients (-.7 and -2, respectively) and higher in the controls (+.3 and +1.1; P < .001) at study closure.

CONCLUSIONS

There was an improvement in renal function, graft survival, and obesity-related co-morbidities among kidney transplant recipients who underwent bariatric surgery compared with those who did not. These findings support bariatric surgery in this population and warrant prospective studies.

Bilirubin, a new therapeutic for kidney transplant?

In patients with end-stage renal disease, kidney transplantation has been associated with numerous benefits, including increased daily activity, and better survival rates. However, over 20% of kidney transplants result in rejection within five years. Rejection is primarily due to a hypersensitive immune system and ischemia/reperfusion injury. Bilirubin has been shown to be a potent antioxidant that is capable of potentially reversing or preventing damage from reactive oxygen species generated from ischemia and reperfusion. Additionally, bilirubin has several immunomodulatory effects that can dampen the immune system to promote organ acceptance. Increased bilirubin has also been shown to have a positive impact on renal hemodynamics, which is critical post-transplantation. Lastly, bilirubin levels have been correlated with biomarkers of successful transplantation. In this review, we discuss a multitude of potentially beneficial effects that bilirubin has on kidney acceptance of transplantation based on numerous clinical trials and animal models. Exogenous bilirubin delivery or increasing endogenous levels pre- or post-transplantation may have therapeutic benefits.

Kidney allograft failure in the steroid-free immunosuppression era: A matched case-control study

We studied the causes and predictors of death-censored kidney allograft failure among 1670 kidney recipients transplanted at our center in the corticosteroid-free maintenance immunosuppression era. As of January 1, 2012, we identified 137 recipients with allograft failure; 130 of them (cases) were matched 1-1 for recipient age, calendar year of transplant, and donor type with 130 recipients with functioning grafts (controls). Median time to allograft failure was 29 months (interquartile range: 18-51). Physician-validated and biopsy-confirmed categories of allograft failure were as follows: acute rejection (21%), glomerular disease (19%), transplant glomerulopathy (13%), interstitial fibrosis tubular atrophy (10%), and polyomavirus-associated nephropathy (7%). Graft failures were attributed to medical conditions in 21% and remained unresolved in 9%. Donor race, donor age, human leukocyte antigen mismatches, serum creatinine, urinary protein, acute cellular rejection, acute antibody-mediated rejection, BK viremia, and CMV viremia were associated with allograft failure. Independent predictors of allograft failure were acute cellular rejection (odds ratio: 18.31, 95% confidence interval: 5.28-63.45) and urine protein ≥1 g/d within the first year post-transplantation (5.85, 2.37-14.45). Serum creatinine ≤1.5 mg/dL within the first year post-transplantation reduced the odds (0.29, 0.13-0.64) of allograft failure. Our study has identified modifiable risk factors to reduce the burden of allograft failure.

Is big bad or bearable? Long-term renal transplant outcomes in obese recipients

BACKGROUND

The global obesity epidemic has implications for kidney transplantation. There are conflicting reports regarding the impact of obesity on long-term post-transplant outcomes.

AIM

To explore the impact of body mass index (BMI) on long-term outcomes after kidney transplantation.

DESIGN

The association between BMI and cardiovascular disease, cancer, post-transplant diabetes mellitus, graft and recipient survival was investigated in recipients who had been transplanted at least ten years previously.

METHODS

All consecutive adult renal transplant recipients who received first, deceased donor, transplants between 1986 and 2005 in Northern Ireland were followed-up until 2016.

RESULTS

A total of 328 patients were eligible. Of them, 96 were overweight with a BMI 25.0-29.9 kg/m2, and 56 were obese with a BMI exceeding 29.9 kg/m2. Median follow-up time was 16.7 years. In multivariate analysis recipient BMI was associated with the development of post-transplant diabetes mellitus (P=0.003), but not with new cardiovascular disease (P=0.78). Cancer was less common in recipients with a higher BMI (hazard ratio (HR) 0.58, P < 0.001). BMI at the time of transplantation did not significantly influence graft (P=0.28) or recipient survival (P=0.13).

CONCLUSIONS

Increased BMI at time of transplantation is associated with an increased risk of post-transplant diabetes mellitus but not new cardiovascular disease or malignancy. Long-term graft and recipient survival is not impacted. Potential recipients should not be excluded from transplantation solely on the basis of obesity, rather it should be considered as one part of an individualized risk stratification, based on comorbidity and considering the risk of death on maintenance dialysis.

The Role of Bariatric Surgery in Abdominal Organ Transplantation-the Next Big Challenge?

Obesity is linked to inferior transplant outcome. Bariatric surgery (BS) is an established treatment of morbid obesity. We provide an overview on BS in the field of kidney (KT) and liver transplantation (LT). In end-stage renal disease (ESRD) and KT patients, BS seems safe and feasible. Complication rates were slightly higher compared to the non-transplant population, whereas weight loss and improvement of comorbidities were comparable. Sleeve gastrectomy (SG) was the preferred procedure before KT and superior to gastric bypass (GB) in regard to mortality and morbidity. If conducted after KT, both procedures showed comparable results. BS before LT was associated with high complication rates, in particular after GB. Albeit distinct complications, SG conducted after LT showed the best results. Immunosuppression (IS) changes after BS were rare.

Obesity in the Kidney Transplant Process

Obesity, which has become an increasing problem worldwide, poses a risk for kidney transplant recipients both before and after surgery. In this literature review, we studied the effects of obesity before and after kidney transplant. There are numerous studies and different opinions on the effects of obesity on graft function before and after transplant. Obesity prolongs surgery time and the ischemic process. A large cohort study of 11 836 recipients noted a close association between body mass index and delayed renal transplant and delayed graft function. However, another study found that being overweight or obese before transplant did not have any effects over the medium and long term. A 20-year follow-up study indicated that the firstyear body mass index in recipients after renal transplant had a greater effect on graft function and survival than body mass index before transplant. Still, another study found that body mass index had no effects on graft function and survival. In the study, 3-year graft function and mortality rates of morbidly obese people without diabetes, the functional status without dialysis, and living-donor transplant were reported to be much lower than in those with normal weight. In conclusion, there is no consensus on the effects of obesity before and after transplant, and it has been pointed out that more research should be done on this subject.

Laparoscopic sleeve gastrectomy improves renal transplant candidacy and posttransplant outcomes in morbidly obese patients

Morbid obesity is a barrier to kidney transplantation due to inferior outcomes, including higher rates of new-onset diabetes after transplantation (NODAT), delayed graft function (DGF), and graft failure. Laparoscopic sleeve gastrectomy (LSG) increases transplant eligibility by reducing BMI in kidney transplant candidates, but the effect of surgical weight loss on posttransplantation outcomes is unknown. Reviewing single-center medical records, we identified all patients who underwent LSG before kidney transplantation from 2011-2016 (n = 20). Post-LSG kidney recipients were compared with similar-BMI recipients who did not undergo LSG, using 2:1 direct matching for patient factors. McNemar's test and signed-rank test were used to compare groups. Among post-LSG patients, mean BMI ± standard deviation (SD) was 41.5 ± 4.4 kg/m² at initial encounter, which decreased to 32.3 ± 2.9 kg/m² prior to transplantation (P < .01). No complications, readmissions, or mortality occurred following LSG. After transplantation, one patient (5%) experienced DGF, and no patients experienced NODAT. Allograft and patient survival at 1-year posttransplantation was 100%. Compared with non-LSG patients, post-LSG recipients had lower rates of DGF (5% vs 20%) and renal dysfunction-related readmissions (10% vs 27.5%) (P < .05 each). Perioperative complications, allograft survival, and patient survival were similar between groups. These data suggest that morbidly obese patients with end-stage renal disease who undergo LSG to improve transplant candidacy, achieve excellent posttransplantation outcomes.

One-Year Outcomes of a Cohort of Renal Transplant Patients Related to BMI in a Steroid-Sparing Regimen

Background

The prevalence of overweight and obese kidney transplant recipients (KTR) has risen in parallel to the obesity epidemic that has affected the general population over the last two decades. At present, there is an ongoing debate regarding the suitability for transplantation of obese patients.

Methods

Data were prospectively collected on consecutive single organ KTR transplanted between January 2014 and March 2016. The patients were stratified according to their body mass index (BMI) using the World Health Organization classification. As a measure of allograft function Modification of Diet in Renal Disease, estimated glomerular filtration rate was used at 3, 6, and 12 months posttransplant.

Results

We included 370 KTR: 126 of 370 women; median age, 52.7 years (range, 19-77 years), followed up for a median of 19.5 ± 8.6 months. In total, 155 (41.9%) KTR were underweight or of normal BMI at transplant, whereas 148 (40%) were overweight, and 67 (18.1%) were classified as obese (47 [12.7%] class 1, 11 [3%] class 2, 9 [2.4%] class 3). Overweight and obese KTR had a higher incidence of pretransplant diabetes (P = 0.021), but no difference was found in new-onset hyperglycemia posttransplant (P = 0.35). There was also no difference in posttransplant hospital length of stay (P = 0.386). Obese and overweight KTR had a significantly lower estimated glomerular filtration rate than underweight and normal BMI KTR at 3 and 6 months posttransplant, a finding that did not persist at 1 year follow-up. Overall, 23 patients lost their grafts, and 20 patients died during follow-up. Kaplan Meier analysis showed no difference in allograft loss between the different BMI groups (log rank P = 0.7).

Conclusions

In this single-center study, which used short-term data, overweight and obese patients were shown not to have inferior outcomes regarding renal function 1 year posttransplant.

Body mass index as a predictor of outcomes among pediatric kidney transplant recipient

Controversies exist regarding the impact of obesity on patients undergoing kidney transplantation. We sought to estimate the association between BMI and patient outcomes (survival and graft function) among pediatric kidney transplant patients in the USA. We conducted a retrospective analysis of the United Network for Organ Sharing database (1987-2013), which revealed 13 014 pediatric patients (<18 years old) who underwent primary kidney transplantation. Patients were stratified into five BMI categories established by the World Health Organizations according to their Z score, which is based on age, gender and BMI. The -2, 0, and +2 categories were collapsed and served as the reference group, while the -3 (thin) and +3 (obese) categories were evaluated for differences in graft and patient survival. The survival rates between these categories were compared using the Kaplan-Meier estimator. Cox proportional hazards models were constructed to adjust for recipient and donor characteristics to estimate the risk of graft loss and mortality associated with BMI. Logistic regression models were estimated to evaluate whether there was an association between BMI and DGF. There were no differences in overall patient (P=.1655) or graft (P=.1688) survival between the severely thin, normal, and obese patients. Adjusted models also revealed no statistically significant differences in graft or patient survival. There were no differences in the odds of DGF (both unadjusted and adjusted) among the three groups. The prevalence of obesity is increasing among children who present for kidney transplant in the USA. In this national study of pediatric kidney transplant recipients, there was no difference in graft or patient survival and no differences in rates of DGF among obese children compared to normal and underweight children undergoing kidney transplantation.

Predictive Score for Posttransplantation Outcomes

BACKGROUND

Most current scoring tools to predict allograft and patient survival upon kidney transplantion are based on variables collected posttransplantation. We developed a novel score to predict posttransplant outcomes using pretransplant information including routine laboratory data available before or at the time of transplantation.

METHODS

Linking the 5-year patient data of a large dialysis organization to the Scientific Registry of Transplant Recipients, we identified 15 125 hemodialysis patients who underwent first deceased transplantion. Prediction models were developed using Cox models for (a) mortality, (b) allograft loss (death censored), and (c) combined death or transplant failure. The cohort was randomly divided into a two thirds set (Nd = 10 083) for model development and a one third set (Nv = 5042) for validation. Model predictive discrimination was assessed using the index of concordance, or C statistic, which accounts for censoring in time-to-event models (a-c). We used the bootstrap method to assess model overfitting and calibration using the development dataset.

RESULTS

Patients were 50 ± 13 years of age and included 39% women, 15% African Americans, and 36% persons with diabetes. For prediction of posttransplant mortality and graft loss, 10 predictors were used (recipients' age, cause and length of end-stage renal disease, hemoglobin, albumin, selected comorbidities, race and type of insurance as well as donor age, diabetes status, extended criterion donor kidney, and number of HLA mismatches). The new model (www.TransplantScore.com) showed the overall best discrimination (C-statistics, 0.70; 95% confidence interval [95% CI], 0.67-0.73 for mortality; 0.63; 95% CI, 0.60-0.66 for graft failure; 0.63; 95% CI, 0.61-0.66 for combined outcome).

CONCLUSIONS

The new prediction tool, using data available before the time of transplantation, predicts relevant clinical outcomes and may perform better to predict patients' graft survival than currently used tools.