Retrospective analysis of the impact of severe obesity on kidney transplant outcomes

Obesity-associated Inflammation and Alloimmunity

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

Metabolic Risk Profile and Graft Function Deterioration 2 Years After Kidney Transplant

Importance

Studies exploring the association of body weight and metabolic status with graft function deterioration (GFD) after kidney transplantation have produced inconsistent findings. Few studies have examined whether metabolically healthy overweight or obesity (MHO) may contribute to GFD.

Objective

To evaluate associations of overweight or obesity and metabolic disorders with GFD in recipients of kidney transplant.

Design, Setting, and Participants

This multicenter retrospective cohort study was conducted from January 1, 2020, through June 30, 2021, with a follow-up period of 2 years after kidney transplantation. Participants included adult recipients of cadaveric kidney transplant in 4 transplantation centers in China. Participants were classified as 4 metabolic phenotypes according to their BMI and metabolic status. Data were analyzed from July to August 2023.

Exposures

Overweight and obesity were characterized by body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) of 24 or greater. Metabolic disorder was identified by existence of a minimum of 2 of 4 conditions: hypertension, hyperglycemia, increased triglyceride, and decreased high-density lipoprotein cholesterol.

Main Outcome and Measures

The main outcome was GFD, defined as a decrease in estimated glomerular filtration rate of at least 25% within 6 months to 2 years after transplant.

Results

A total of 1260 adult recipients of cadaveric kidney transplant (mean [SD] age, 43.97 [11.51] years; 755 [59.92%] male) were included in the study, and 127 (10.08%) participants experienced the primary outcome of GFD during follow-up. After accounting for confounding factors in multivariable analyses, overweight or obesity (odds ratio [OR], 1.64; 95% CI, 1.10-2.44; P = .02) and metabolic disorder (OR, 1.71; 95% CI, 1.12-2.63; P = .01) were associated with increased risk of GFD. The MHO subgroup exhibited a greater risk for GFD (OR, 2.37; 95% CI, 1.01-5.57; P = .048) compared with participants who did not have overweight or obesity or metabolic disorder. All components of metabolic disorder, with the exception of elevated triglyceride, were associated with GFD. There was a dose-response association of number of metabolic disorder components (OR per 1 additional condition, 1.40; 95% CI, 1.20-1.63; P < .001) and BMI (OR per 1-unit increase, 1.90; 95% CI, 1.03-1.15; P = .002) with increased risk for GFD. A nonlinear association was observed between BMI and risk of GFD.

Conclusions and Relevance

In this cohort study of recipients of cadaveric kidney transplant, individuals with overweight or obesity or metabolic disorder had a significantly higher risk of experiencing GFD. Individuals with MHO had an elevated risk for graft function deterioration. Additional studies with larger sample size and longer follow-up are necessary to validate our findings.

The Impact and Effectiveness of Weight Loss on Kidney Transplant Outcomes: A Narrative Review

Obesity is a worldwide epidemic that leads to several non-communicable illnesses, including chronic kidney disease (CKD). Diet and lifestyle modifications have shown a limited impact in the treatment of obesity. Because the group of end-stage renal disease (ESRD) patients examined in this study had limited access to kidney transplantation (KT), patients with obesity were thought to be at an increased risk of intraoperative and postoperative KT complications. Although bariatric surgery (BS) is now recognized as the gold standard treatment for morbid obesity, its role in ESRD or kidney transplant patients remains unknown. It is critical to know the correlation between weight loss and complications before and after KT, the impact of the overall graft, and patients' survival. Hence, this narrative review aims to present updated reports addressing when to perform surgery (before or after a KT), which surgical procedure to perform, and again, if strategies to avoid weight regain must be specific for these patients. It also analyzes the metabolic alterations produced by BS and studies its cost-effectiveness pre- and post-transplantation. Due to the better outcomes found in KT recipients, the authors consider it more convenient to perform BS before KT. However, more multicenter trials are required to provide a solid foundation for these recommendations in ERSD patients with obesity.

Abdominal Organ Transplantation: Noteworthy Literature in 2022

This review highlights noteworthy literature published in 2022 pertinent to anesthesiologists and critical care physicians caring for patients undergoing abdominal organ transplantation. We begin by exploring the impacts that the COVID-19 pandemic has had across the field of abdominal organ transplantation, including the successful use of grafts procured from COVID-19-infected donors. In pancreatic transplantation, we highlight several studies on dexmedetomidine and ischemia-reperfusion injury, equity in transplantation, and medical management, as well as studies comparing pancreatic transplantation to islet cell transplantation. In our section on intestinal transplantation, we explore donor selection. Kidney transplantation topics include cardiovascular risk management, obesity, and intraoperative management, including fluid resuscitation, dexmedetomidine, and sugammadex. The liver transplantation section focuses on clinical trials, systematic reviews, and meta-analyses published in 2022 and covers a wide range of topics, including machine perfusion, cardiovascular issues, renal issues, and coagulation/transfusion.

Obesity and kidney transplantation

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

Body mass index affects kidney transplant outcomes: A cohort study over 5 years using a steroid sparing protocol

BACKGROUND

There is controversy regarding the suitability of high body mass index (BMI) candidates accessing the transplant waitlist.

PATIENTS AND METHODS

Observational study on consecutive kidney transplant recipients undergoing surgery between January 2014 and March 2016 at our center. Patients were stratified according to BMI. Survival outcomes and graft function were analyzed to investigate the effect of donor's and recipient's demographic characteristics.

RESULTS

396 kidney transplant recipients: 260 males, mean age 51.8 ± 15.9 years, followed up for a mean time of 5.86 ± 2.29 years. Mean BMI 26.2 ± 5.1. BMI class 1 (20 ≤ BMI ≤ 24.9) n=133, class 2 (25 ≤ BMI ≤ 29.9) n= 155, class 3 (30 ≤ BMI ≤34.9) n=53, class 4 (BMI ≥ 35) n=21, class V (BMI ≤ 19.9) n=34. Patient survival was not significantly different according to the recipient's BMI class (p=0.476); graft survival was affected (p=0.031), as well as graft function up to 2 years post-transplant and at 4 years follow up (p=0.016). At logistic regression the factors independently associated with graft loss were only donor's age (p=0.05) and BMI class of the recipient (p=0.002).

CONCLUSIONS

Obesity did not impact on patient's survival but affected graft function and graft loss.