Renal Transplant Wound Complications in the Modern Era of Obesity

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.

Recipient race modifies the association between obesity and long-term graft outcomes after kidney transplantation

Donor and recipient obesity (defined using body mass index [BMI]) are associated with worse outcomes after kidney transplant (KT). In adult KT recipients identified using the Scientific Registry of Transplant Recipients (2000-2017), we examined the modifying effect of recipient race on recipient obesity (BMI > 30 kg/m2) and combined donor and recipient (DR) obesity pairing, with death-censored graft loss (DCGL), all-cause graft loss (ACGL), and short-term graft outcomes using multivariable Cox proportional hazards models and logistic regression. Obesity was associated with a higher risk of DCGL in White (adjusted hazard ratio [aHR], 1.29; 95% CI, 1.25-1.35) than Black (aHR, 1.13; 95% CI, 1.08-1.19) recipients. White, but not Black, recipients with obesity were at higher risk for ACGL (aHR, 1.08; 95% CI, 1.05-1.11, for White recipients; aHR, 0.99; 95% CI, 0.95-1.02, for Black recipients). Relative to nonobese DR, White recipients with combined DR obesity experienced more DCGL (aHR, 1.38; 95% CI, 1.29-1.47 for White; aHR, 1.19; 95% CI, 1.10-1.29 for Black) and ACGL (aHR, 1.12; 95% CI, 1.07-1.17 for White; aHR, 1.00; 95% CI, 0.94-1.07 for Black) than Black recipients. Short-term obesity risk was similar irrespective of race. An elevated BMI differentially affects long-term outcomes in Black and White KT recipients; uniform BMI thresholds to define transplant eligibility are likely inappropriate.

Wound related complications and the anterior rectus sheath versus Gibson approach to kidney transplantation: A single center randomized controlled trial

INTRODUCTION

Wound related complications (WRC) are a significant source of morbidity in kidney transplant recipients, and may be mitigated by surgical approach. We hypothesize that the anterior rectus sheath approach (ARS) may decrease WRC and inpatient opiate use compared to the Gibson Approach (GA).

METHODS

This double-blinded randomized controlled trial allocated kidney transplant recipients aged 18 or older, exclusive of other procedures, 1:1 to ARS or GA at a single hospital. The ARS involves a muscle-splitting paramedian approach to the iliopsoas fossa, compared to the muscle-cutting GA. Patients and data analysts were blinded to randomization.

RESULTS

Seventy five patients were randomized to each group between August 27, 2019 and September 18, 2020 with a minimum 12 month follow-up. There was no difference in WRC between groups (p = .23). Nine (12%) and three patients (4%) experienced any WRC in the ARS and GA groups, respectively. Three and one Clavien IIIb complications occurred in the ARS and GA groups, respectively. In a multiple linear regression model, ARS was associated with decreased inpatient opioid use (β = -58, 95% CI: -105 to -12, p = .016).

CONCLUSIONS

The ARS did not provide a WRC benefit in kidney transplant recipients, but may be associated with decreased inpatient opioid use.

Obesity and renal disease: Benefits of bariatric surgery

The prevalence of obesity, a preventable and reversible condition with a high impact on health, continues to rise, especially after the COVID-19 pandemic. Severe overweight is well recognized as a risk factor for diabetes and hypertension, among other conditions, that may increase cardiovascular risk. Obesity has grown simultaneously with a rise in the prevalence of chronic kidney disease, and a pathophysiological link has been established, which explains its role in generating the conditions to facilitate the emergence and maximize the impact of the risk factors of chronic kidney disease and its progression to more advanced stages. Knowing the mechanisms involved and having different tools to reverse the overweight and its consequences, bariatric surgery has arisen as a useful and efficient method, complementary or alternative to others, such as lifestyle changes and/or pharmacotherapy. In a detailed review, the mechanisms involved in the renal consequences of obesity, the impact on risk factors, and the potential benefit of bariatric surgery at different stages of the disease and its progression are exposed and analyzed. Although the observational evidence supports the value of bariatric surgery as a renoprotective measure in individuals with obesity, diabetic or not, randomized studies are expected to establish evidence-based recommendations that demonstrate its positive risk-benefit balance as a complementary or alternative therapeutic tool.

Combined Donor-Recipient Obesity and the Risk of Graft Loss After Kidney Transplantation

Background: As the prevalence of obesity increases globally, appreciating the effect of donor and recipient (DR) obesity on graft outcomes is of increasing importance.

Methods: In a cohort of adult, kidney transplant recipients (2000–2017) identified using the SRTR, we used Cox proportional hazards models to examine the association between DR obesity pairing (body mass index (BMI) >30 kg/m2), and death-censored graft loss (DCGL) or all-cause graft loss, and logistic regression to examine risk of delayed graft function (DGF) and ≤30 days graft loss. We also explored the association of DR weight mismatch (>30 kg, 10-30 kg (D>R; D<R) and <10 kg (D = R)) with each outcome, stratifying by DR obesity pairing.

Results: Relative to non-obese DR, obese DR were highest risk for all outcomes (DCGL: HR 1.26, 95% CI 1.22–1.32; all-cause graft loss: HR 1.09, 95% CI 1.06–1.12; DGF: OR 1.98, 95% CI 1.89–2.08; early graft loss: OR 1.34, 95% CI 1.19–1.51). Donor obesity modified the risk of recipient obesity and DCGL [p = 0.001] and all-cause graft loss [p < 0.001] but not DGF or early graft loss. The known association of DR weight mismatch with DCGL was attenuated when either the donor or recipient was obese.

Conclusion: DR obesity status impacts early and late post-transplant outcomes.

Impact of Obesity in Kidney Diseases

The clinical consequences of obesity on the kidneys, with or without metabolic abnormalities, involve both renal function and structures. The mechanisms linking obesity and renal damage are well understood, including several effector mechanisms with interconnected pathways. Higher prevalence of urinary albumin excretion, sub-nephrotic syndrome, nephrolithiasis, increased risk of developing CKD, and progression to ESKD have been identified as being associated with obesity and having a relevant clinical impact. Moreover, renal replacement therapy and kidney transplantation are also influenced by obesity. Losing weight is key in limiting the impact that obesity produces on the kidneys by reducing albuminuria/proteinuria, declining rate of eGFR deterioration, delaying the development of CKD and ESKD, and improving the outcome of a renal transplant. Weight reduction may also contribute to appropriate control of cardiometabolic risk factors such as hypertension, metabolic syndrome, diabetes, and dyslipidemia which may be protective not only in renal damage but also cardiovascular disease. Lifestyle changes, some drugs, and bariatric surgery have demonstrated the benefits.

Recipient gender and body mass index are associated with early acute rejection in donation after cardiac death liver transplantation

BACKGROUND

Early acute rejection (EAR) is a common complication after liver transplantation (LT).

AIM

The aim of this study was to evaluate the incidence and risk factors of EAR in donation after cardiac death (DCD) liver transplantation recipients.

METHOD

We retrospectively analysed the data of 461 DCD liver transplants performed during the period from January 2010 to June 2016 to study the relationship between EAR and various clinical factors. EAR was defined as histologically proven acute cellular rejection occurring less than 90 days after transplantation.

RESULT

The median follow-up time for this study was 33.1 months (range: 0.03-92.8 months). Thirty-two (6.9%) patients developed EAR with a median period of 20.5 days (5-88 days) after transplantation. A multivariate analysis revealed that female recipient (hazard ratio: 2.801; P=0.024) and high recipient body mass index (BMI) (hazard ratio: 1.005; P=0.049) were two independent risk factors for early acute rejection.

CONCLUSIONS

In DCD liver transplantation, recipient female gender and high BMI were associated with a higher incidence of EAR, while the use of CD25-Ab and/or MMF had a protective effect.

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.

Computed-tomography-based predictive scores of surgical complications to help decision-making in enrolling obese patients in kidney transplantation list

This study aimed at developing scores predicting surgical complications in obese transplant recipients, based on preoperative computed tomography (CT) parameters. All consecutive patients with a body mass index (BMI) ≥ 30 kg/m² who underwent kidney transplantation between 2012 and 2019 were included. The preoperative CT parameters were assessed: total fatty surface (TFS), subcutaneous fatty surface (SFS), iliac vessel to skin distance (VSD), and abdominal perimeter (AP). Per- and postoperative complications (vascular, urinary, parietal, and digestive complications) within 30 days were listed. Predictive models of surgical complications were generated based on the results of the logistic regression. Among the 163 patients included, 53 (32.5%) experienced surgical complications. The AP was a risk factor for complications in multivariate analysis (OR: 1.050; 95% CI: 1.016-1.087; p = 0.03). Two predictive models of complications were created based on the statistical analysis: a one-variable model based on AP (sensitivity 86.8%, specificity 41.8%, area under the curve (AUC) 65.3, with a cutoff value of 107 cm) and a five-variable model based on BMI, TFS, SFS, VSD, and AP (sensitivity 73.6%, specificity 57.3%, AUC 66.2). These models, based on patient morphometric measurements, could allow predicting the occurrence of surgical complications in obese candidates for kidney transplantation.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Effect of subcutaneous tissue depth on outcomes of kidney transplantation

Although post-kidney transplant (KT) wound complications are associated with elevated body mass index (BMI), BMI is not an accurate surrogate of obesity. On the other hand, subcutaneous depth (SQD) measurement is a direct marker of truncal obesity. We examined outcomes of differing intraoperative SQD measurements in 113 KT-only recipients over 20 months. Recipients' median age was 51 years; median BMI, 28 kg/m²; and mean SQD, 2.9 cm. Patients were stratified into groups of SQD ≤2.5 cm, >2.5-5 cm, and >5 cm. An SQD of >2.5 to 5 cm correlated with a BMI of 30 kg/m² (obesity) and an SQD >5 cm correlated with a BMI >35 kg/m² (severe obesity). Degree of SQD was not associated with more frequent technical complications such as fascial dehiscence, lymphocele formation, renal artery thrombosis/stenosis, urine leak, or ureteral stenosis. However, an SQD >2.5 cm was a risk factor for requiring a wound vacuum-assisted closure device. There was no difference in graft or patient survival among the three SQD groups. Obesity, as measured directly by SQD, was not associated with increased technical complications or poor outcomes after KT. As expected, there was a higher incidence of wound complications in the higher SQD groups requiring intervention.

Weighing the waitlist: Weight changes and access to kidney transplantation among obese candidates

High body mass index is a known barrier to access to kidney transplantation in patients with end-stage kidney disease. The extent to which weight and weight changes affect access to transplantation among obese candidates differentially by race/ethnicity has received little attention. We included 10 221 obese patients waitlisted for kidney transplantation prior to end-stage kidney disease onset between 1995–2015. We used multinomial logistic regression models to examine the association between race/ethnicity and annualized change in body mass index (defined as stable [-2 to 2 kg/m²/year], loss [>2 kg/m²/year] or gain [>2 kg/m²/year]). We then used Fine-Gray models to examine the association between weight changes and access to living or deceased donor transplantation by race/ethnicity, accounting for the competing risk of death. Overall, 29% of the cohort lost weight and 7% gained weight; 46% received a transplant. Non-Hispanic blacks had a 24% (95% CI 1.12–1.38) higher odds of weight loss and 22% lower odds of weight gain (95% CI 0.64–0.95) compared with non-Hispanic whites. Hispanics did not differ from whites in their odds of weight loss or weight gain. Overall, weight gain was associated with lower access to transplantation (HR 0.88 [95% CI 0.79–0.99]) compared with maintenance of stable weight, but weight loss was not associated with better access to transplantation (HR 0.96 [95% CI 0.90–1.02]), although this relation differed by baseline body mass index and for recipients of living versus deceased donor organs. For example, weight loss was associated with improved access to living donor transplantation (HR 1.24 [95% CI 1.07–1.44]) in whites but not in blacks or Hispanics. In a cohort of obese patients waitlisted before dialysis, blacks were more likely to lose weight and less likely to gain weight compared with whites. Weight loss was only associated with improved access to living donor transplantation among whites. Further studies are needed to understand the reasons for the observed associations.

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.

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.

Abdominoplasty in Hemodialysis Patients Before Transplant

Morbid obesity in patients with chronic kidney disease is a contraindication for inclusion on the kidney transplant waitlist.Despite intentional weightloss,the persistence of the abdominal adipose panniculus poses postoperative risks, such as infection of the surgical site and seromas. We describe 2 cases of patients on hemodialysis who had a body mass index greater than 35 kg/m² who underwent abdominoplasty before transplant without perioperative complications. One patient received a living-related kidney transplant (donor was the brother) without complications.

Panniculectomy at the time of living donor renal transplantation: An 8-year experience

Panniculectomy can be performed as a prophylactic procedure preceding transplantation to enable obese patients to meet criteria for renal transplantation. No literature exists on combined renal transplant and panniculectomy surgery (LRT-PAN). We describe our 8-year experience performing LRT-PAN. A retrospective chart review of all patients who had undergone LRT-PAN from 2010 to 2018 was conducted. Data were collected on patient demographics, allograft survival and function, and postoperative course. Fifty-eight patients underwent LRT-PAN. All grafts survived, with acceptable function at 1 year. Median length of stay was 4 days with a mean operative duration of 363 minutes. The wound complication rate was 24%. Ninety-day readmission rate was 52%, with medical causes as the most common reason for readmission (45%), followed by wound (32%) and graft-related complications (23%). Body mass index, diabetes status, and previous immunosuppression did not influence wound complication rate or readmission (P = .7720, P = .0818, and P = .4830, respectively). Combining living donor renal transplant and panniculectomy using a multidisciplinary team may improve access to transplantation, particularly for the obese and postobese population. This combined approach yielded shorter-than-expected hospital stays and similar wound complication rates, and thus should be considered for patients in whom transplantation might otherwise be withheld on the basis of obesity.

The Evolution of Kidney Transplantation Surgery Into the Robotic Era and Its Prospects for Obese Recipients

Robotic-assisted kidney transplantation (RAKT) represents the most recent innovation in the evolution of kidney transplantation surgery. Vascular techniques enabling kidney transplantation have existed since the early 20th century and contributed to the first successful open kidney transplant procedure in 1954. Technical advances have since facilitated minimally invasive laparoscopic and robotic techniques in live-donor surgery, and subsequently for the recipient procedure. This review follows the development of surgical techniques for kidney transplantation, with a special focus on the advent of robotic-assisted transplantation because of its potential to facilitate transplantation of those deemed previously too obese to transplant by standard means. The different techniques, indications, advantages, disadvantages, and future directions of this approach will be explored in detail. Robot-assisted kidney transplantation may become the preferred means of transplanting morbidly obese recipients, although its availability to such recipients remains extremely limited and strategies targeting weight loss pretransplantation should never be abandoned in favor of a "RAKT-first" approach.

Abdominal wall complications following renal transplantation in adult recipients - factors associated with interventional management in one unit

Background

Abdominal wall surgical site complications following renal transplantation can be challenging to manage. A sub-group of these recipients will require operative management or advanced wound care such as negative pressure wound therapy (NPWT). The aim of this study was to determine if there were any preoperative, intraoperative and postoperative characteristics in our recipients’ cohort which were associated with the requirement for such interventions.

Methods

A retrospective review of medical records was performed for all recipients who sustained abdominal wall complications following renal transplantation at our centre from 2006 to 2016.

Results

A total of 64/828 recipients (7.7%) had abdominal wall complications. The mean weight for these patients was 84.9 kg (±16.6 kg) and the mean body mass index was 30.2 (±5.1). Forty-five recipients (70%) had a superficial wound dehiscence while nine (14%) had a complete fascial dehiscence. Operative intervention was required in 13/64 patients (20%) and was more likely to be required in the presence of a fascial dehiscence (9/9, 100%) or a wound collection (10/31, 32%) (p < 0.001, p = 0.021). NPWT was used in 17/64 patients (27%) and was more commonly required in patients with diabetes mellitus (10/24, 42%), a complete fascial dehiscence (5/9, 56%) or evidence of infection (16/44, 36%) (p = 0.039, p = 0.034, p = 0.008).

Conclusions

The requirement for either operative management or the use of NPWT in the management of abdominal wall complications following renal transplantation in our experience was more common in recipients with diabetes mellitus, and in the setting of either complete fascial dehiscence, abdominal wall wound collections and/ or infection.

Renal Transplant in Obese Patients and Impact of Weight Loss Before Surgery on Surgical and Medical Outcomes: A Single-Center Cohort Study

OBJECTIVES

Previous studies have linked obesity to poor outcomes in renal transplant recipients, prompting many transplant centers to encourage weight loss pretransplant in obese patients. Here, we performed a single-center retrospective study to assess the effects of weight loss on graft and patient outcomes.

MATERIALS AND METHODS

Data from 893 renal transplant recipients at our center from 2007 to 2011 were analyzed. First, renal transplant recipients with a history of obesity before transplant (42%) were compared with nonobese patients. Second, in the obese group, renal transplant recipients with significant weight loss (> 10%) before transplant were compared with other obese renal transplant recipients without significant weight loss.

RESULTS

Renal transplant recipients were predominantly white, with 74% having undergone living-donor transplant. Obese patients were older (56.6 vs 46.7 y old) and had more comorbidities and more surgical complications, in particular wound complications and incisional hernias, posttransplant than nonobese patients (14.7 vs 5.5%, respectively). Patient and graft survival rates were similar to those in nonobese patients. In the obese group, patient characteristics and medical or surgical complications after transplant did not differ between those with or without significant weight loss. However, obese patient and graft survival rates were lower in patients with weight loss than in obese patients without weight loss.

CONCLUSIONS

In our study, weight loss before transplant surgery in obese patients had no influence on surgical outcomes but was associated with a higher mortality rate. A prospective assessment of the impact of weight loss before surgery is needed to establish its usefulness.

The Impact of Waiting List BMI Changes on the Short-term Outcomes of Lung Transplantation

BACKGROUND

Obesity and underweight are associated with a higher postlung transplantation (LTx) mortality. This study aims to assess the impact of the changes in body mass index (BMI) during the waiting period for LTx on early postoperative outcomes.

METHODS

Medical records of 502 consecutive cases of LTx performed at our institution between 1999 and 2015 were reviewed. Patients were stratified per change in BMI category between pre-LTx assessment (candidate BMI) and transplant BMI as follows: A-candidate BMI, less than 18.5 or 18.5 to 29.9 and transplant BMI, less than 18.5; B-candidate BMI, less than 18.5 and transplant BMI, 18.5 to 29.9; C-candidate BMI, 18.5 to 29.9 and transplant BMI, 18.5 to 29.9; D-candidate BMI, 30 or greater and transplant BMI, 18.5 to 29.9; and E-candidate BMI, 30 or greater or 18.5 to 29.9 and transplant BMI, 30 or greater. Our primary outcome was in-hospital mortality and secondary outcomes were length of mechanical ventilation, intensive care unit length of stay (LOS), hospital LOS and postoperative complications.

RESULTS

BMI variation during the waiting time was common, as 1/3 of patients experienced a change in BMI category. Length of mechanical ventilation (21 days vs 9 days; P = 0.018), intensive care unit LOS (26 days vs 15 days; P = 0.035), and rates of surgical complications (76% vs 44%; P = 0.018) were significantly worse in patients of group E versus group D. Obese candidates who failed to decrease BMI less than 30 by transplant exhibited an increased risk of postoperative mortality (odds ratio, 2.62; 95% confidence interval, 1.01-6.48) compared with patients in group C. Pre-LTx BMI evolution had no impact on postoperative morbidity and mortality in underweight patients.

CONCLUSIONS

Our results suggest that obese candidates with an unfavorable pretransplant BMI evolution are at greater risk of worse post-LTx outcomes.

Obesity and access to kidney transplantation in patients starting dialysis: A prospective cohort study

Background

Obesity has been linked to poor access to medical care. Although scientific evidence suggest that kidney transplantation improves survival and quality of life in obese patients with end-stage renal disease (ESRD), few data exist on the impact of obesity on access to kidney transplantation in this population.

Objectives

We aimed to characterize the relationships between body mass index (BMI) at the start of dialysis, changes in BMI after the start of dialysis, and either access to kidney transplantation or overall mortality in dialysis or transplantation among ESRD patients.

Methods

Between 2002 and 2011, 19524 dialysis patients with ESRD were included in the study via the French nationwide Renal Epidemiology and Information Network. Data on sociodemographic factors, comorbidities and laboratory test results were recorded upon entry into the registry. BMI were obtained at the start of dialysis and then yearly. Cubic spline regression analyses provided a graphic evaluation of the relationships between BMI at the start of dialysis and outcomes. Joint models were used to evaluate the association between the change over time in BMI and outcomes.

Results

During a median follow-up of 20.3 months, 6634 patients underwent kidney transplantation. A BMI >31 kg/m² at the start of the dialysis was associated with a lower likelihood of receiving a kidney transplant, and the likelihood decreased even further with higher BMI values. For patients with BMI ≥30kg/m² at the start of the dialysis, a 1 kg/m² decrease in BMI during follow-up was associated with a 9% to 11% increase in the likelihood of receiving a transplant. There was an L-shaped relationship between BMI at the start of dialysis and overall mortality. We showed that obese patients with ESRD face barriers to the receipt of a kidney transplant without valid reasons.

Conclusion

Greater attention to this issue would improve the fairness of the organ allocation process and might improve outcomes for obese patients with ESRD.

Management of the obese kidney transplant candidate

Obesity is an increasingly common condition that can exclude end stage renal disease patients from consideration of kidney transplantation. The optimal management of obese transplant candidates is uncertain, especially the use of pharmacologic therapies or bariatric surgery. We review the rationale to consider transplantation in obese patients, the impact of obesity on access to kidney transplantation, the evidence for obese patients to lose weight loss prior to kidney transplantation, peri-operative management considerations and specific weight loss strategies prior to transplantation. We also propose an algorithm for pre-transplant management of obese transplant candidates that takes into consideration the patient's peri-operative risk, the anticipated time to transplantation and the risk of delayed graft function. Finally, we suggest a number of areas in need of further research as well as health policy considerations to improve the care of obese kidney transplant candidates.

Laparoscopic sleeve gastrectomy: gateway to kidney transplantation

BACKGROUND

The prevalence of obesity and obesity-related morbidity in end-stage renal disease patients is rising. Although it is established that obesity does not abrogate the transplant benefit with respect to lower long-term mortality and cardiovascular risk, it is associated with increased graft failure, delayed graft function, surgical complications, prolonged hospital stay, and costs.

OBJECTIVES

To examine the safety and efficacy of LSG (laparoscopic sleeve gastrectomy) in renal transplant candidates and evaluate transplant outcomes.

SETTING

Single-center prospective nonrandomized trial METHODS: We here report on a prospective single-center trial establishing a 2-step approach for obese renal transplant candidates. Patients with end-stage renal disease and a BMI (body mass index) of 35 kg/m² or higher underwent laparoscopic sleeve gastrectomy. After reaching a BMI of<35 kg/m², patients were waitlisted for kidney transplantation. Age, gender, body mass index (BMI), associated co-morbidities, cause of end-stage renal disease, surgical complications, and outcome after kidney transplantation (graft survival, incidence of delayed graft function, incidence of rejection, serum creatinine) were collected.

RESULTS

LSG was performed in 8 renal transplant candidates with a mean BMI of 38.8 kg/m² each. BMI dropped to below 35 kg/m² within a median of 3 months. Percent excess body mass index loss (%EBMIL) was 62.7% at 1 year after LSG. Within 17 months (mean) after metabolic surgery, 7 patients underwent kidney transplantation. All transplants were successful with a serum creatinine of 1.9±.8 mg/dL at discharge and stable allograft function thereafter. Mean follow-up was 3.2±1.4 years; no patient was lost to follow-up.

CONCLUSION

LSG is safe and efficacious for treatment of obesity in renal transplant candidates. Rapid and sustained weight loss and subsequent waitlisting for kidney transplantation may reduce overall and in particular posttransplant patient morbidity.

Chronic wounds should be one of Australia's National Health Priority Areas

Chronic wounds are a poorly recognised chronic disease that cause pain and suffering and cost the Australian healthcare system A $2.85 billion dollars per annum. Unlike the highly profiled and relatively well-funded chronic diseases that comprise the Australian National Health Priority Areas, chronic wounds remain a largely hidden and poorly supported problem in the Australian community. This perspective article proposes that one approach to generate action to reduce the burden of chronic wounds is to better articulate the relationship between chronic wounds and the Australian National Health Priority Areas, and to establish a profile of chronic wounds as a chronic disease of national significance in its own right. This approach has the potential to raise awareness of the significance of chronic wounds and garner support from the public, healthcare sector, research funders and policy makers to improve the outcomes for people who are living with or at risk of developing this condition and to potentially reduce expenditure in this area.

Absence of the Effect of Pretransplant Body Mass Index on Post Kidney Transplant Outcomes

CONTEXT

Obesity has been reported as risk factor for reduced posttransplant graft and patient survival and increased delayed graft function (DGF).

OBJECTIVE

The purpose of this work is to analyze the effect of body mass index (BMI) on defined transplant outcomes in patients transplanted under defined guidelines in a kidney transplant program.

DESIGN

Review of a prospectively collected database in renal transplant recipients receiving rabbit antithymocyte globulin induction, mycophenolate mofetil, tacrolimus, and early corticosteroid withdrawal between 2001 and 2011.

SETTING

This review was conducted in a single abdominal transplant program in the United States.

MAIN OUTCOME MEASURES

Primary outcome was death-censored graft survival categorized by posttransplant body mass groups. Secondary outcomes included DGF as well as patient survival.

RESULTS

Four hundred sixty seven patients were identified. No difference was observed in graft survival or DGF between BMI groups. One-year, death-censored graft survival and patient survival rates ranged from 97.5% to 100% and 96.6% to 100%, respectively. Delayed graft function was uncommon across all BMI groups, ranging from 5.3% to 9.1%, with the lowest incidence in patients with a BMI ≥ 35 kg/m(2). Biopsy-proven acute rejection rates at 1 year were similar across all groups (10.1%-14%) as were estimated glomerular filtration rates were at 1, 3, and 5 years.

CONCLUSION

Our results do not show an effect of BMI on posttransplant outcomes, suggesting that relaxation of BMI criteria may be warranted for recipient selection.

Complex kidneys for complex patients: the risk associated with transplantation of kidneys with multiple arteries into obese patients

Conflicting evidence surrounds clinical outcomes in obese individuals after transplantation; nonetheless, many are denied the opportunity to receive a transplant. Allografts with complex vascular anatomy are regularly used in both deceased and living donor settings. We established the risk of transplanting kidneys with multiple renal arteries into obese recipients. A retrospective analysis of data from 1095 patients undergoing renal transplantation between January 2004 and July 2013 at a single centre was conducted. Of these, 24.2% were obese (body mass index >30 kg/m(2)), whereas 25.1% of kidneys transplanted had multiple arteries, thereby making the transplantation of kidneys of complex anatomy into obese recipients a relatively common clinical occurrence. Vessel multiplicity was associated with inferior 1-year graft survival (85.8.% vs 92.1%, P = .004). Obese patients had worse 1-graft survival compared to those of normal BMI (86.8% vs 93.8%, P = .001). The risk of vascular complications and of graft loss within a year after transplantation were greater when grafts with multiple arteries were transplanted into obese recipients as compared to their nonobese counterparts (RR 2.00, CI 95% 1.07-3.65, and RR 1.95, CI 95% 1.02-3.65). Additionally, obese patients faced significantly higher risk of graft loss if receiving a kidney with multiple arteries compared to one of normal anatomy (RR 1.97, 95% CI 1.02-3.72). Thus, obese patients receiving complex anatomy kidneys face poorer outcomes, which should be considered when allocating organs, seeking consent, and arranging for aftercare.

Addressing morbid obesity as a barrier to renal transplantation with laparoscopic sleeve gastrectomy

Morbid obesity is a barrier to renal transplantation and is inadequately addressed by medical therapy. We present results of a prospective evaluation of laparoscopic sleeve gastrectomy (LSG) for patients failing to achieve significant weight loss with medical therapy. Over a 25-month period, 52 obese renal transplant candidates meeting NIH guidelines for metabolic surgery underwent LSG. Mean age was 50.0 ± 10.0 years with an average preoperative BMI of 43.0 ± 5.4 kg/m(2) (range 35.8-67.7 kg/m(2)). Follow-up after LSG was 220 ± 152 days (range 26-733 days) with last BMI of 36.3 ± 5.3 kg/m(2) (range 29.2-49.8 kg/m(2)) with 29 (55.8%) patients achieving goal BMI of <35 kg/m(2) at 92 ± 92 days (range 13-420 days). The mean percentage of excess weight loss (%EWL) was 32.1 ± 17.6% (range 6.7-93.8%). A segmented regression model was used to compare medical therapy versus LSG. This revealed a statistically significant increase in the BMI reduction rate (0.3 kg/m(2)/month versus 1.1 kg/m(2)/month, p < 0.0001). Patients also experienced a 40.9% decrease in anti-hypertensive medications (p < 0.001) and a 49.7% decrease in total daily insulin dose (p < 0.001). LSG is a safe and effective means for addressing obesity in kidney transplant candidates in the context of a multidisciplinary approach.

[Is obesity a barrier to kidney transplantation?]

INTRODUCTION

Kidney transplantation is the most suitable of ESRD care. The proportion of obese people is increasing in the general population and patients with kidney impairment. It is important to assess the impact of obesity on surgical complications of kidney transplantation. The aim of this retrospective study was to signify the correlation between obesity and the occurrence of postoperative urological complications during the first year.

METHODS

We conducted a retrospective study from March 1999 to December 2009. We conducted a chart review of patients undergoing kidney transplantation. The kidneys were taken from cadaveric donors. Data collected included age, weight, height, preoperative BMI; causal nephropathy, smoking, hypertension, diabetes, anticoagulation therapy. Intraoperative data included operative time (DO), cold ischemia. Urological complications were recorded during the first year after the kidney transplantation (vascular anastomotic strictures, ureterovesical stenosis, lymphorrheas, pyelonephritis, hematoma, wound infection). Statistical analysis consisted of a t-test for independent samples and univariate and multivariate logistic regression for the occurrence of complications.

RESULTS

Four hundred and twenty-two patients were transplanted in total. We excluded 20 patients. BMI and duration of surgery patients with complications were significantly different from those of patients with no complications (P=0.016 and P=0.039, respectively). Obese (n=48) had more diabetes (12.5% versus 3.7%, P=0.014), were more often smoking (35.4% versus 22%, P=0.012), had a longer DO (203.64minutes versus 182.46minutes, P=0.006), and complications (62.5% versus 50.28%, P=0.03) than patients with a BMI <30 (n=354). After adjusting for age, smoking, DO, diabetes and BMI showed that only BMI was an independent predictor of the occurrence of postoperative complications with P=0.048 and RR=1.058 [CI: 1 to 1.119]. However, there was no more transplantectomy obese (P=0.911).

CONCLUSION

Our study showed that there is a significant risk of surgical complications after kidney transplantation in obese patients. But ultimately, this does not affect graft survival because there are no more transplantectomies or return to dialysis.

LEVEL OF EVIDENCE

5.

Differential association of body mass index with access to kidney transplantation in men and women

BACKGROUND AND OBJECTIVES

Obese patients encounter barriers to medical care not encountered by lean patients, and inequities in access to care among obese patients may vary by sex. This study aimed to determine the association of body mass index (BMI) with access to kidney transplantation in men and women.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In this retrospective analysis of 702,456 incident ESRD patients aged 18-70 years (captured in the US Renal Data System between 1995 and 2007), multivariate time-to-event analyses were used to determine the association of BMI with likelihood of transplantation from any donor source, transplantation from a living donor, and transplantation from a deceased donor, as well the individual steps in obtaining a deceased donor transplant (activation to the waiting list, and transplantation after wait-listing).

RESULTS

Among women, a BMI ≥ 25.0 kg/m(2) was associated with a lower likelihood of transplantation from any donor source (hazard ratio [HR], 0.75; 95% confidence interval [95% CI], 0.73 to 0.77), transplantation from a living donor (HR, 0.75; 95% CI, 0.72 to 0.77), and transplantation from a deceased donor (HR, 0.74; 95% CI, 0.72 to 0.77). By contrast, among men, a BMI of 25.0-34.9 kg/m(2) was associated with a higher likelihood of the outcomes of transplantation from any donor source (HR, 1.08; 95% CI, 1.06 to 1.11), transplantation from a living donor (HR, 1.18; 95% CI, 1.13 to 1.22), and transplantation from a deceased donor (HR, 1.05; 95% CI, 1.02 to 1.07). Among men, the level beyond which BMI was associated with a lower likelihood of transplantation from any donor source or a living donor was ≥ 40.0 kg/m(2), and ≥ 35.0 kg/m(2) in the case of deceased donor transplantation.

CONCLUSIONS

The association of BMI with access to transplantation varies between men and women. The reasons for this difference should be further studied.

Increased recipient body mass index is associated with acute rejection and other adverse outcomes after kidney transplantation

BACKGROUND

Outcomes of kidney transplant recipients with increased body mass index (BMI) remain controversial. We studied the relationship between BMI and clinically relevant outcomes among kidney transplant recipients at a large center.

METHODS

We performed an observational cohort study of all recipients of kidney transplants at our center from January 1, 2000 to December 31, 2010 to determine if increased BMI at transplantation is associated with adverse outcomes, including delayed graft function and biopsy-proven acute rejection (BPAR). Recipient BMI was categorized as <20, 20 to 24.9 (reference), 25 to 29.9, 30 to 34.9, and ≥35 kg/m. Potential confounders were included in logistic and Cox proportional hazards models.

RESULTS

A total of 1151 patients were studied. Recipient BMI of 30 to 34.9 and ≥35 kg/m were associated with an increased risk of delayed graft function (odds ratio [95% confidence interval [CI], 1.92 [1.16-3.19] and 4.49 [2.24-9.00], respectively). BMI≥35 kg/m was also associated with an increased risk of BPAR (hazard ratio [HR; 95% CI], 2.43 [1.48-3.99]), all-cause graft failure (HR [95% CI], 1.97 [1.09-3.56]), and death-censored graft failure (HR [95% CI], 2.43 [1.07-5.51]). Adjustment for acute rejection as a time-varying covariate significantly attenuated the association with graft failure endpoints. There was no significant relation between BMI and death with graft function.

CONCLUSIONS

Increased BMI at kidney transplantation is a predictor of adverse outcomes, including BPAR. The role of pretransplantation weight reduction in improving graft and patient outcomes requires further study.

Obesity and organ transplantation: successes, failures, and opportunities

The increasing rate of societal obesity is also affecting the transplant world through obesity in candidates and donors as well as its posttransplant repercussions. Being overweight and obese has been shown to have significant effects on both short- and long-term complications as well as patient and graft survival. However, much of the comorbidity can be controlled or prevented with careful patient selection and aggressive management. A team approach to managing obesity and its comorbidities both pre- and posttransplant is essential for successful transplant outcomes. Complicating understanding the results of obesity research is the inclusion different weight categories, use of listing vs transplant weights, patient populations large enough for statistical power, and changes in transplant management, especially immunosuppression protocols, anti-infection protocols, and operative techniques. Much more research is needed regarding many elements, including safe weight loss before transplantation, prevention of weight gain after transplant, genomic influences, and the role of bariatric surgery in the transplant process.

The survival benefit of kidney transplantation in obese patients

Obese patients have a decreased risk of death on dialysis but an increased risk of death after transplantation, and may derive a lower survival benefit from transplantation. Using data from the United States between 1995 and 2007 and multivariate non-proportional hazards analyses we determined the relative risk of death in transplant recipients grouped by body mass index (BMI) compared to wait-listed candidates with the same BMI (n = 208 498). One year after transplantation the survival benefit of transplantation varied by BMI: Standard criteria donor transplantation was associated with a 48% reduction in the risk of death in patients with BMI ≥ 40 kg/m(2) but a ≥ 66% reduction in patients with BMI < 40 kg/m2. Living donor transplantation was associated with ≥ 66% reduction in the risk of death in all BMI groups. In sub-group analyses, transplantation from any donor source was associated with a survival benefit in obese patients ≥ 50 years, and diabetic patients, but a survival benefit was not demonstrated in Black patients with BMI ≥ 40 kg/m(2). Although most obese patients selected for transplantation derive a survival benefit, the benefit is lower when BMI is ≥ 40 kg/m(2), and uncertain in Black patients with BMI ≥ 40 kg/m(2).

Obesity and body composition for transplant wait-list candidacy--challenging or maintaining the BMI limits?

Most kidney transplantation programs have a maximum body mass index (BMI) above which they will not place a patient on the active waiting list. However, obesity is common among patients with end-stage renal disease (ESRD), and weight loss is difficult, resulting in many patients being denied the opportunity to be considered for a transplant. BMI limits are in place because of data that outcomes are worse among obese transplant recipients than among those with lower BMI. However, the data to suggest that patient and graft survival are affected by obesity are not consistent, and obese patients with ESRD have better survival after kidney transplantation compared with remaining on dialysis. Therefore, it is important to carefully examine the question of BMI limits to ensure that we are achieving the right balance and making the best use of donated kidneys.

Wound healing complications and the use of mammalian target of rapamycin inhibitors in kidney transplantation: a critical review of the literature

Surgical complications, including events such as lymphocele and urological complications that affect wound healing, are reported with an incidence of 15% to 32% after kidney transplantation. The experience of the surgeon and comorbidities play an important role in determining the risk of such complications occurring. Since the introduction of the inosine 5'-monophosphate dehydrogenase inhibitors (mycophenolate mofetil) to the immunosuppressive armamentarium, replacing the antimetabolite prodrug azathioprine, reports have associated certain forms of wound healing complications (wound dehiscence, impaired healing, lymphocele, and incisional hernia) with the use of these agents. When mammalian target of rapamycin (mTOR) inhibitors (sirolimus, everolimus) became available, these findings were observed increasingly, particularly in direct comparisons with inosine 5'-monophosphate dehydrogenase inhibitors. The purpose of this article was to review the reported incidence of wound healing complications from randomized clinical trials that investigated the use of sirolimus- and everolimus-based treatment regimens in de novo kidney transplantation and the information available from the U.S. Food and Drug Administration database. The clinical trials included were primarily identified using biomedical literature database searches, with additional studies added at the authors' discretion. This review summarizes these studies to consider whether modern mTOR inhibitor-based immunosuppressive regimens exert and affect wound healing after kidney transplantation.

Diet-induced obesity alters the differentiation potential of stem cells isolated from bone marrow, adipose tissue and infrapatellar fat pad: the effects of free fatty acids

Introduction

Obesity is a major risk factor for several musculoskeletal conditions that are characterized by an imbalance of tissue remodeling. Adult stem cells are closely associated with the remodeling and potential repair of several mesodermally derived tissues such as fat, bone, and cartilage. We hypothesized that obesity would alter the frequency, proliferation, multipotency, and immunophenotype of adult stem cells from a variety of tissues.

Materials and Methods

Bone marrow-derived mesenchymal stem cells (MSCs), subcutaneous adipose-derived stem cells (sqASCs), and infrapatellar fat pad-derived stem cells (IFP cells) were isolated from lean and high-fat diet induced obese mice, and their cellular properties were examined. To test the hypothesis that changes in stem cell properties were due to the increased systemic levels of free fatty acids (FFAs), we further investigated the effects of FFAs on lean stem cells in vitro.

Results

Obese mice showed a trend toward increased prevalence of MSCs and sqASCs in the stromal tissues. While no significant differences in cell proliferation were observed in vitro, the differentiation potential of all types of stem cells was altered by obesity. MSCs from obese mice demonstrated decreased adipogenic, osteogenic, and chondrogenic potential. Obese sqASCs and IFP cells showed increased adipogenic and osteogenic differentiation, but decreased chondrogenic ability. Obese MSCs also showed decreased CD105 and increased PDGFRα expression, consistent with decreased chondrogenic potential. FFA treatment of lean stem cells significantly altered their multipotency but did not completely recapitulate the properties of obese stem cells.

Conclusions

These findings support the hypothesis that obesity alters the properties of adult stem cells in a manner that depends on the cell source. These effects may be regulated in part by increased levels of FFAs, but may involve other obesity-associated cytokines. These findings contribute to our understanding of mesenchymal tissue remodeling with obesity, as well as the development of autologous stem cell therapies for obese patients.