Association of the Metabolic Syndrome and Long-Term Renal Function in Kidney Donors

Recommendations for living donor kidney transplantation

This Guide for Living Donor Kidney Transplantation (LDKT) has been prepared with the sponsorship of the Spanish Society of Nephrology (SEN), the Spanish Transplant Society (SET), and the Spanish National Transplant Organization (ONT). It updates evidence to offer the best chronic renal failure treatment when a potential living donor is available. The core aim of this Guide is to supply clinicians who evaluate living donors and transplant recipients with the best decision-making tools, to optimise their outcomes. Moreover, the role of living donors in the current KT context should recover the level of importance it had until recently. To this end the new forms of incompatible HLA and/or ABO donation, as well as the paired donation which is possible in several hospitals with experience in LDKT, offer additional ways to treat renal patients with an incompatible donor. Good results in terms of patient and graft survival have expanded the range of circumstances under which living renal donors are accepted. Older donors are now accepted, as are others with factors that affect the decision, such as a borderline clinical history or alterations, which when evaluated may lead to an additional number of transplantations. This Guide does not forget that LDKT may lead to risk for the donor. Pre-donation evaluation has to centre on the problems which may arise over the short or long-term, and these have to be described to the potential donor so that they are able take them into account. Experience over recent years has led to progress in risk analysis, to protect donors' health. This aspect always has to be taken into account by LDKT programmes when evaluating potential donors. Finally, this Guide has been designed to aid decision-making, with recommendations and suggestions when uncertainties arise in pre-donation studies. Its overarching aim is to ensure that informed consent is based on high quality studies and information supplied to donors and recipients, offering the strongest possible guarantees.

Changes in cardiometabolic risk factors and metabolic syndrome over time in living kidney donors: a retrospective cohort study

BACKGROUND

permissibility in the selection of living kidney donors (LKD) with one or more cardiometabolic risk factors (CMRFs) and/or metabolic syndrome (MS) is an increasingly frequent practice worldwide. These factors, together with kidney donation specifically, are known to be associated with an increased risk of chronic kidney disease (CKD).

METHODS

we analyzed the frequency of CMRFs and MS before and after kidney donation in LKD. In the secondary analysis, we associated CMRFs and MS with renal function. The SPSS V22.0 software was used.

RESULTS

we analyzed 110 LKD patients, with a mean age of 35.05 ± 10.5 years: 63 (57.3 %) men and 47 (42.7 %) women. Patients were followed for 25 ± 17.48 months after nephrectomy. Prior to donation, 62 patients (56.4 %) had MS, and the presence of one to six CMRFs was 19.1 %, 32 %, 18.2 %, 17.3 %, 3.6 %, and 0.9 %, respectively. During follow-up, in donors, the incidence of overweight increased from 48.2 % to 52.7 %, (p < 0.01); that of obesity increased from 11.8 % to 20.9 % (p < 0.01); that of hyperuricemia increased from 17.3 % to 26.4 %, (p < 0.01); that of hypercholesterolemia increased from 24.5 % to 33.6 % (p < 0.01); and that of hypertriglyceridemia increased from 47.3 % to 50.9 % (p < 0.01), while the incidence of MS decreased from 56.4 % to 51.8 % (p < 0.01). A logistic regression analysis showed that the presence of CMRFs did not show any association with glomerular filtration rates below 60 mL/min/1.73 m2.

CONCLUSION

LKD had a high frequency of CMRFs and MS at the time of donation, and over time, the incidence of CMRFs significantly increased. Because these factors, together with kidney donation, could be associated with an increased risk of CKD, we must evaluate protocols for LKD and consider stricter criteria in the selection of LKD, with an emphasis on follow-up protocols to address CMRFs and MS.

Metabolic Syndrome, a Real Barrier for Living Kidney Donor Transplant

INTRODUCTION

Renal transplantation is the optimal renal replacement therapy. In Mexico, most of the kidney transplants are from living donors. It is essential to identify conditions that increase the risk of developing chronic kidney disease (CKD) in donors, such as metabolic syndrome (MS).

MATERIALS AND METHODS

In retrospect from January 2008 to December 2018, the donation protocols for renal transplantation of the Hospital Central Sur Alta Especialidad "Picacho" were reviewed, classifying all the cases of donors by nephrectomy or no nephrectomy and describing the demographic characteristics, prevalence of metabolic diseases, and cause of rejection of the protocol.

RESULTS

A total of 178 donors were studied: 82 women (46%), 96 men (54%), mean age of 42 years, average body mass index (BMI) 27.9 kg/m², glomerular filtration rate (GFR) by Chronic Kidney Disease Epidemiology Collaboration 99 mL/min, 59 patients with grade I and II obesity (BMI ≥ 30 kg/m²), and 1 patient with morbid obesity (BMI ≥ 40 kg/m²). A total of 39 patients (22%) underwent nephrectomy and 139 (78%) did not. The following characteristics and alterations were found: Of the 139 patients who did not undergo nephrectomy, 91 had metabolic disorders, 20 had low GFR, 21 had albuminuria, and 4 recipients received cadaveric transplants, 3 due to critical conditions of the recipient. The metabolic alterations in the rejected donors were as follows: MS 54 (59%), prediabetes 55 (39%), newly diagnosed hypertension 70 (76%), diabetes mellitus 20 (14%), obesity 47 (51.6%), dyslipidemia 76 (83%), hyperuricemia 17 (12%).

DISCUSSION

The prevalence of MS in apparently healthy donors is similar to that of other studies in Mexico. Both MS and its components are independently associated with an increased risk of cardiovascular disease and CKD. It has been shown that these donors have a greater degree of glomerular and interstitial fibrosis; therefore, diagnosis, prevention, and timely treatment in this group are important.

Preoperative Comorbidities and Outcomes of Medically Complex Living Kidney Donors

Introduction

Recent reports have described an increased risk of renal disease in living kidney donors compared with the general population. However, these reports do not detail the outcomes of medically complex living donors (MCLDs) with preoperative comorbidities (PCs), such as hypertension, dyslipidemia, glucose intolerance, and obesity. Analysis of living donors with end-stage renal disease (ESRD) has shown that these PCs may contribute significantly to the development of ESRD. We aimed to evaluate the effect of PCs on postoperative renal function and mortality in MCLDs.

Methods

Between January 2008 and December 2016, 807 living-donor kidney transplants were performed in our unit. Of these, 802 donors completed postoperative follow-up of >5 months. Donors were stratified into 4 groups based on the number of PCs present: healthy living donors (HLDs) with no PCs (n = 214) or MCLDs with 1 PC (n = 302), 2 PCs (n = 196), or 3 PCs (n = 90) (denoted MCLD [PC 1], MCLD [PC 2], or MCLD [PC 3], respectively). We compared pathology observation data from baseline biopsy, postoperative estimated glomerular filtration rate (eGFR), postoperative urinary protein concentration, and mortality between HLD and MCLD groups.

Results

Interstitial fibrosis, tubular atrophy, glomerulosclerosis, and arteriolosclerosis were more frequent in MCLDs (PC 3) than in HLDs. No significant differences were identified between HLDs and MCLDs in terms of postoperative eGFR and short-term mortality. Overt proteinuria and ESRD were not observed.

Conclusions

Appropriate postdonation management of MCLDs with PCs may result in similar outcomes as for HLDs.

Impact of screening for metabolic syndrome on the evaluation of obese living kidney donors

BACKGROUND

We report our experience with metabolic syndrome screening for obese living kidney donor candidates to mitigate the long-term risk of CKD.

METHODS

We retrospectively reviewed 814 obese (BMI≥30) and 993 nonobese living kidney donor evaluations over 12 years. Using logistic regression, we explored interactions between social/clinical variables and candidate acceptance before and after policy implementation.

RESULTS

Obese donor candidate acceptance decreased after metabolic syndrome screening began (56.3%, 46.3%, p < 0.01), while nonobese candidate acceptance remained similar (59.6%, 59.2%, p = 0.59). Adjusting for age, gender, race, BMI, and number of prior evaluations, acceptance of obese candidates decreased significantly more than nonobese (p = 0.025). In candidates without metabolic syndrome, there was no significant change in how age, sex, race, or BMI affected a donor candidate's probability of acceptance.

CONCLUSION

Metabolic syndrome screening is a simple stratification tool for centers with liberal absolute BMI cut-offs to exclude potentially higher-risk obese candidates.

The liver and the kidney: two critical organs influencing the atherothrombotic risk in metabolic syndrome

The increased atherothrombotic risk in patients with metabolic syndrome (MetS) has been classically explained by the multiplicative effect of systemic concomitant pro-atherosclerotic factors. In particular, centripetal obesity, dyslipidaemia, glucose intolerance, hypertension (differently combined in the diagnosis of the disease) would be expected to act as classical cardiovascular risk conditions underlying accelerated atherogenesis. In order to better understand specific atherosclerotic pathophysiology in MetS, emerging evidence focused on the alterations in different organs that could serve as both pathophysiological targets and active players in the disease. Abnormalities in adipose tissue, heart and arteries have been widely investigated in a variety of basic research and clinical studies in MetS. In this narrative review, we focus on pathophysiological activities of the liver and kidney. Considering its key role in metabolism and production of soluble inflammatory mediators (such as C-reactive protein [CRP]), the liver in MetS has been shown to be altered both in its structure and function. In particular, a relevant amount of the fat accumulated within this organ has been shown to be associated with different degrees of inflammation and potential insulin resistance. In humans, non-alcoholic fatty liver disease (NAFLD) has been described as the hepatic manifestation of MetS. In an analogous manner, epidemiological evidence strongly suggested a "guilty" association between MetS and chronic kidney disease (CKD). Some biomarkers of hepatic (such as C-reactive protein, TNF-alpha or other cytokines) and renal diseases (such as uric acid) associated with MetS might be particularly useful to better manage and prevent the atherothrombotic risk.

Association of metabolic syndrome with kidney function and histology in living kidney donors

The selection of living kidney donors is based on a formal evaluation of the state of health. However, this spectrum of health includes subtle metabolic derangements that can cluster as metabolic syndrome. We studied the association of metabolic syndrome with kidney function and histology in 410 donors from 2005 to 2012, of whom 178 donors were systematically followed after donation since 2009. Metabolic syndrome was defined as per the NCEP ATPIII criteria, but using a BMI > 25 kg/m(2) instead of waist circumference. Following donation, donors received counseling on lifestyle modification. Metabolic syndrome was present in 50 (12.2%) donors. Donors with metabolic syndrome were more likely to have chronic histological changes on implant biopsies than donors with no metabolic syndrome (29.0% vs. 9.3%, p < 0.001). This finding was associated with impaired kidney function recovery following donation. At last follow-up, reversal of metabolic syndrome was observed in 57.1% of donors with predonation metabolic syndrome, while only 10.8% of donors developed de novo metabolic syndrome (p < 0.001). In conclusion, metabolic syndrome in donors is associated with chronic histological changes, and nephrectomy in these donors was associated with subsequent protracted recovery of kidney function. Importantly, weight loss led to improvement of most abnormalities that define metabolic syndrome.

Practice patterns in evaluation of living kidney donors in United Network for Organ Sharing-approved kidney transplant centers

INTRODUCTION

The current pattern of evaluation for living kidney donors was investigated.

METHODS

We designed a 37-question electronic survey to collect information about living kidney donor evaluation. Of the 181 United Network for Organ Sharing (UNOS)-approved centers, 72 responded. Survey responses were coded and downloaded into SPSS. Data was expressed as means and standard deviations or the percentage of centers with specific responses.

RESULTS

66% of the centers used a cut-off of <80 ml/min for exclusion of living kidney donors. 24-hour urine measuring creatinine clearance (CrCl) was the most common screening method for glomerular filtration rate (GFR) assessment in potential living donors. 56% of the centers excluded donors with blood pressure (BP) >140/90, whereas 22.7 and 7.1% excluded patients with pre-hypertension with a cut-off BP of 130/85 and 120/80, respectively. 66% of the centers used 24-hour urine creatinine to assess for proteinuria. 20% of the centers accepted living kidney donors with microalbuminuria and 84% accepted patients with a history of nephrolithiasis. 24% of the centers reported use of formal cognitive testing of potential living donors.

DISCUSSION

There were significant variations in exclusion criteria based on GFR, history of kidney stones, body mass index, BP and donors with urinary abnormalities. The definitions for hematuria and proteinuria were variable. There is a need for uniformity in selection and for a living donor registry. We also recommend raising the cut-off for estimated GFR to 90 ml/min to account for 10-15% overestimation when CrCl is used.