Mediterranean style diet is associated with low risk of new-onset diabetes after renal transplantation

Bridging the Gap Between CKD Management Paradigms in Transplant and Nontransplant Settings: Published Evidence, Challenges, and Perspectives

Kidney transplantation (KT) is the best treatment for patients with kidney failure, associated with improved survival and quality of life compared with maintenance dialysis. However, despite constant improvements in the assessment and management of the alloimmune response, KT patients frequently demonstrate a reduced estimated glomerular filtration rate. Therefore, the usual complications of chronic kidney disease (CKD), such as anemia, hypertension, metabolic acidosis, hyperkalemia, or persistent secondary hyperparathyroidism, are highly prevalent after KT. However, their underlying mechanisms are different in the transplant setting (compared with the nontransplanted CKD population), and management recommendations are based on relatively poor-quality data. In recent years, new therapies have emerged, significantly improving kidney and cardiovascular outcomes of non-KT patients with CKD. Whether those new drugs could improve the outcomes of KT patients has largely been under investigated so far. In this review, we will address the challenges of the management of a KT patient with a reduced estimated glomerular filtration rate, cover the published evidence, and highlight the critical knowledge gaps.

New-Onset Diabetes Mellitus after Kidney Transplantation

New-Onset Diabetes Mellitus after Transplantation (NODAT) emerges as a prevalent complication post-kidney transplantation, with its incidence influenced by variations in NODAT definitions and follow-up periods. The condition's pathophysiology is marked by impaired insulin sensitivity and β-cell dysfunction. Significant risk factors encompass age, gender, obesity, and genetics, among others, with the use of post-transplant immunosuppressants intensifying the condition. NODAT's significant impact on patient survival and graft durability underscores the need for its prevention, early detection, and treatment. This review addresses the complexities of managing NODAT, including the challenges posed by various immunosuppressive regimens crucial for transplant success yet harmful to glucose metabolism. It discusses management strategies involving adjustments in immunosuppressive protocols, lifestyle modifications, and pharmacological interventions to minimize diabetes risk while maintaining transplant longevity. The importance of early detection and proactive, personalized intervention strategies to modify NODAT's trajectory is also emphasized, advocating for a shift towards more anticipatory post-transplant care.

International consensus on post-transplantation diabetes mellitus

Post-transplantation diabetes mellitus (PTDM) remains a leading complication after solid organ transplantation. Previous international PTDM consensus meetings in 2003 and 2013 provided standardized frameworks to reduce heterogeneity in diagnosis, risk stratification and management. However, the last decade has seen significant advancements in our PTDM knowledge complemented by rapidly changing treatment algorithms for management of diabetes in the general population. In view of these developments, and to ensure reduced variation in clinical practice, a 3rd international PTDM Consensus Meeting was planned and held from 6-8 May 2022 in Vienna, Austria involving global delegates with PTDM expertise to update the previous reports. This update includes opinion statements concerning optimal diagnostic tools, recognition of prediabetes (impaired fasting glucose and/or impaired glucose tolerance), new mechanistic insights, immunosuppression modification, evidence-based strategies to prevent PTDM, treatment hierarchy for incorporating novel glucose-lowering agents and suggestions for the future direction of PTDM research to address unmet needs. Due to the paucity of good quality evidence, consensus meeting participants agreed that making GRADE (Grading of Recommendations, Assessment, Development, and Evaluations) recommendations would be flawed. Although kidney-allograft centric, we suggest that these opinion statements can be appraised by the transplantation community for implementation across different solid organ transplant cohorts. Acknowledging the paucity of published literature, this report reflects consensus expert opinion. Attaining evidence is desirable to ensure establishment of optimized care for any solid organ transplant recipient at risk of, or who develops, PTDM as we strive to improve long-term outcomes.

Diet quality and cardiovascular outcomes: A systematic review and meta-analysis of cohort studies

AIMS

To evaluate relationships between diet quality and cardiovascular outcomes.

METHODS

Six databases were searched for studies published between January 2007 and October 2021. Eligible studies included cohort studies that assessed the relationship between a priori diet quality and cardiovascular disease mortality and morbidity in adults. The Academy of Nutrition and Dietetics Checklist was used to assess the risk of bias. Study characteristics and outcomes were extracted from eligible studies using standardised processes. Data were summarised using risk ratios for cardiovascular disease incidence and mortality with difference compared for highest versus lowest diet quality synthesised in meta-analyses using a random effects model.

RESULTS

Of the 4780 studies identified, 159 studies (n = 6 272 676 adults) were included. Meta-analyses identified a significantly lower cardiovascular disease incidence (n = 42 studies, relative risk 0.83, 95% CI 0.82-0.84, p < 0.001) and mortality risk (n = 49 studies, relative risk 0.83, 95% CI 0.82-0.84, p < 0.001) among those with highest versus lowest diet quality. In sensitivity analyses of a high number of pooled studies (≥13 studies) the Mediterranean style diet patterns and adherence to the heart healthy diet guidelines were significantly associated with a risk reduction of 15% and 14% for cardiovascular disease incidence and 17% and 20% for cardiovascular disease mortality respectively (p < 0.05).

CONCLUSIONS

Higher diet quality is associated with lower incidence and risk of mortality for cardiovascular disease however, significant study heterogeneity was identified for these relationships.

Immunosuppressive Therapy and Nutritional Status of Patients after Kidney Transplantation: A Protocol for a Systematic Review

(1) Background: Kidney transplantation is widely recognized as the most effective method of treating end-stage renal disease. Immunosuppressive therapy plays a pivotal role in the treatment of kidney transplant patients, encompassing all patients (except identical twins), and is administered from organ transplantation until the end of its function. The aim of this systematic review is to identify the evidence of the association between immunosuppressive therapy and nutritional status of patients following kidney transplantation. (2) Methods: This protocol has been designed in line with Preferred Items for Systematic Reviews (PRISMA-P). Our search encompasses several databases, including MEDLINE (via PubMed), EMBASE (Elsevier), Scopus and Web of Science. We intend to include observational studies (cross-sectional, case-control, and cohort designs), randomized controlled trials (RCTs), as well as completed and ongoing non-randomized study designs. We will confine our search to studies published in English within the past decade (from inception to 17 February 2023). Qualitative studies, case studies, and conference reports will be excluded. The selection process will be done in Covidence by two independent reviewers. Data extraction will be conducted using a standardized MS Excel template version 16.0. Quality assessment of included studies will be performed using the Cochrane Risk of Bias tool for randomized trials (RoB2), or the Risk of Bias in Non-randomized Studies of Interventions (ROBINS-I) tool. Risk-of-bias plots will be generated using the web application Robvis. Relevant data that have been extracted from eligible studies will be presented in a narrative synthesis. We expect the studies to be too heterogeneous to perform subgroup analyses. (3) Conclusion: This systematic review will offer insights into the evidence regarding association between immunosuppressive therapy and nutritional status of adult patients (18 years of age or older) within the initial year following kidney transplantation. To our knowledge, there is no systematic review addressing that question.

Triglyceride-Glucose Index and Cardiovascular Events in Kidney Transplant Recipients

Introduction

Kidney transplant recipients (KTRs) have an increased risk of cardiovascular (CV) events (CVEs) compared with the general population. The impact of insulin resistance on CV risk after transplantation is not well defined.

Methods

We tested whether triglyceride-glucose (TyG) index, a surrogate marker of insulin resistance, may predict posttransplant CVEs in a cohort of 715 consecutive KTRs all included 1 year after transplant.

Results

Follow-up was 9.1 ± 4.6 years. Mean TyG at inclusion was 4.75 ± 0.29 (median, 4.73 [4.14-5.84]). In multiple regression analysis, having a TyG above the median value was associated with higher body mass index (BMI), low high-density lipoprotein (HDL) cholesterol level, and greater urinary protein excretion. A total of 127 CVEs (17.7%) occurred during the study period. In univariate analysis, TyG was strongly associated with CVE occurrence (hazard ratio [HR] 2.06, 95% CI 1.42-3.50, for each increase of 0.1 in TyG, P < 0.001). The best predictive value was 4.87 (HR 6.32, 95% CI 3.30-12.11, P < 0.001). The risk of CVE gradually increased with higher TyG index (quartile 2, HR 1.71, 95% CI 0.84-5.20, P = 0.139; quartile 3, HR 3.12, 95% CI 1.61-6.02, P < 0.001; quartile 4, HR 7.46, 95% CI 4.03-13.80, P < 0.001, vs. quartile 1). TyG remained associated with CVE in multivariate analysis (HR 2.11, 95% CI 1.22-3.68, for each increase of 0.1 in TyG, P < 0.001).

Conclusion

Insulin resistance, as measured by the TyG index is strongly associated with CVE in KTRs. Improving insulin sensitivity seems to be a major issue to prevent CV morbidity and mortality in this high-risk population.

Vegetable Intake, but Not Fruit Intake Is Inversely Associated With Fasting Plasma Glucose in Kidney Transplant Recipients

BACKGROUND

The association between dietary intake and glycemic control has been extensively investigated in type 2 diabetes. However, little is known about this association in kidney transplant recipients (KTRs).

METHODS

We performed an observational study involving 263 adult KTRs with a functioning allograft for at least 1 year at the outpatient clinic of the Hospital from November 2020 to March 2021. Dietary intake was assessed by food frequency questionnaire. Linear regression analyses were performed to evaluate the association between fruit and vegetable intake and fasting plasma glucose.

RESULTS

The vegetable and fruit intake were 238.24 g/d (102.38-416.67) and 511.94 g/d (321.19-849.05), respectively. The fasting plasma glucose was 5.15 ± 0.95 mmol/L. The linear regressions revealed that vegetable intake, but not fruit intake was inversely associated with fasting plasma glucose in KTRs (adjusted R2 = 0.203, P < .001). The clear dose-response relation was observed. Moreover, each 100 g increase in vegetable intake was associated with 11.6% reduction of fasting plasma glucose.

CONCLUSIONS

Vegetable intake, but not fruit intake, is inversely associated with fasting plasma glucose in KTRs.

Cardiovascular disease risk factors and lifestyle modification strategies after pediatric kidney transplantation: what are we dealing with, and what can we target?

Kidney transplantation in pediatric patients can lead to partial improvement of some of the cardiometabolic parameters that increase the risk for cardiovascular disease (CVD) in patients with chronic kidney disease. However, even after restoration of kidney function, transplant recipients remain at risk for CVD due to the continual presence of traditional and non-traditional risk factors, including the side effects of immunosuppression and chronic inflammation. This educational review describes the prevalence of CVD risk factors in pediatric kidney transplant recipients and presents available evidence for therapeutic lifestyle changes and other non-pharmacologic strategies that can be used to improve traditional and modifiable CVD risk factors. Although trial-grade evidence for interventions that improve CVD in pediatric kidney transplant recipients is limited, potential strategies include lowering dietary sodium and saturated fat intake and increasing physical activity levels. Intensive follow-up may help patients achieve guideline-recommended goals for reducing their overall CVD risk.

Adherence to Mediterranean Diet in Individuals on Renal Replacement Therapy

Patients on renal replacement therapy are typically subject to several dietary restrictions; however, this approach has been questioned in recent years, with some suggesting that the Mediterranean diet might be beneficial. Data on the adherence to this diet and factors that influence it are scarce. We conducted a web survey among individuals on renal replacement therapy (dialysis or kidney transplant, KT) using the MEDI-LITE questionnaire to assess adherence to the Mediterranean diet and dietary habits in this population. Adherence to the Mediterranean diet was generally low, and significantly lower among participants on dialysis versus KT recipients (19.4% vs. 44.7%, p < 0.001). Being on dialysis, adopting fluid restrictions, and having a basic level of education were predictors of low adherence to the Mediterranean diet. Consumption of foods typically included in the Mediterranean diet, including fruit, legumes, fish, and vegetables, was generally low, particularly among those on dialysis. There is a need for strategies to improve both the adherence to and the quality of the diet among individuals on renal replacement therapy. This should be a shared responsibility between registered dietitians, physicians, and the patient.

Diabetic Kidney Disease in Post-Transplant Diabetes Mellitus: Causes, Treatment and Outcomes

Kidney transplant recipients are a unique subgroup of chronic kidney disease patients due to their single functioning kidney, immunosuppressive agent usage, and long-term complications related to transplantation. Post-transplant diabetes mellitus (PTDM) has a significant adverse effect on renal outcomes in particular. As transplantations enable people to live longer, cardiovascular morbidity and mortality become more prevalent, and PTDM is a key risk factor for these complications. Although PTDM results from similar risk factors to those of type 2 diabetes, the conditions differ in their pathophysiology and clinical features. Transplantation itself is a risk factor for diabetes due to chronic exposure to immunosuppressive agents. Considering current evidence, this article describes the risk factors, pathogenesis, diagnostic criteria, prevention strategies, and management of PTDM. The therapeutic options are discussed regarding their safety and potential drug-drug interactions with immunosuppressive agents.

Interventions Against Posttransplantation Diabetes: A Scientific Rationale for Treatment Hierarchy Based on Literature Review

Posttransplant diabetes (PTD) is a common medical complication after solid organ transplantation. Because of adverse outcomes associated with its development and detrimental impact on long-term survival, strategies to prevent or manage PTD are critically important but remain underresearched. Treatment hierarchies of antidiabetic therapies in the general population are currently being revolutionized based on cardiovascular outcome trials, providing evidence-based rationale for optimization of medical management. However, opportunities for improving medical management of PTD are challenged by 2 important considerations: (1) translating clinical evidence data from the general population to underresearched solid organ transplant cohorts and (2) targeting treatment based on primary underlying PTD pathophysiology. In this article, the aim is to provide an overview of PTD treatment options from a new angle. Rationalized by a consideration of underlying PTD pathophysiological defects, which are heterogeneous among diverse transplant patient cohorts, a critical appraisal of the published literature and summary of current research in progress will be reviewed. The aim is to update transplant professionals regarding medical management of PTD from a new perspective tailored therapeutic intervention based on individualized characteristics. As the gap in clinical evidence between management of PTD versus type 2 diabetes widens, it is imperative for the transplant community to bridge this gap with targeted clinical trials to ensure we optimize outcomes for solid organ transplant recipients who are at risk or develop PTD. This necessary clinical research should help efforts to improve long-term outcomes for solid transplant patients from both a patient and graft survival perspective.

Associations between Advanced Glycation End Products, Body Composition and Mediterranean Diet Adherence in Kidney Transplant Recipients

There is limited evidence on the associations between dietary patterns, body composition, and nonclassical predictors of worse outcomes such as advanced glycation end products (AGE) in kidney transplant recipients (KTRs). The aim of this cross-sectional study was to determine the level of AGE-determined cardiovascular (CV) risk in Dalmatian KTRs and possible associations between AGE, adherence to the Mediterranean diet (MeDi), and nutritional status. Eighty-five (85) KTRs were enrolled in this study. For each study participant, data were collected on the level of AGE, as measured by skin autofluorescence (SAF), Mediterranean Diet Serving Score (MDSS), body mass composition, anthropometric parameters, and clinical and laboratory parameters. Only 11.76% of the participants were adherent to the MeDi. Sixty-nine percent (69%) of KTRs had severe CV risk based on AGE, while 31% of KTRs had mild to moderate CV risk. The results of the LASSO regression analysis showed that age, dialysis type, dialysis vintage, presence of CV and chronic kidney disease, C- reactive protein level, urate level, percentage of muscle mass, and adherence to recommendations for nuts, meat, and sweets were identified as positive predictors of AGE. The negative predictors for AGE were calcium, phosphate, cereal adherence according to the MeDi, and trunk fat mass. These results demonstrate extremely low adherence to the MeDi and high AGE levels related CV risk in Dalmatian KTRs. Lifestyle interventions in terms of CV risk management and adherence to the MeDi of KTRs should be taken into consideration when taking care of this patient population.

Obesity and Lifestyle Habits among Kidney Transplant Recipients

Background: Obesity may negatively impact clinical outcomes in kidney transplant (KT) recipients. Limited information is available on the prevalence of obesity in this population, and on the lifestyle habits associated with obesity. Methods: we conducted an online, anonymous survey to assess of the proportion of KT recipients with obesity, adherence to the Mediterranean diet (i.e., a dietary regimen with proven renal and cardiovascular outcomes) using the MEDI-Lite questionnaire, and level of physical activity using the International Physical Activity Questionnaire (IPAQ) short form among KT recipients. Results: 255 KT recipients participated. Median (25th−75th quartile) age was 56.0 (48.0; 62.0) years, 43.9% female, median BMI 23.9 (21.6; 26.5) kg/m2. The proportion of KT recipients with obesity was 9.8% (95% confidence interval, 6.4 to 14.1%). Adequate adherence to the Mediterranean diet (Medi-Lite score >9) was overall low (44.7%; 40.0 vs. 45.2% in those with or without obesity, respectively; p = 0.618). In participants with obesity the Medi-Lite score inversely correlated with BMI (R = −0.45; p < 0.025). Overall, 30.6% of participants had a low level of physical activity (44.0 vs. 29.1% of those with or without obesity, respectively; p = 0.125). The amount of energy expended walking was significantly lower among participants with obesity (462 (0.0; 1436) vs. 1056 (433; 2005) METs/week, p = 0.017). Conclusions: the burden of obesity among KT recipients is similar to that of the general population. Adherence to the Mediterranean diet was generally low, and nearly one-third of participants had a low level of physical activity. Building specialized multidisciplinary teams to manage obesity in KT recipients is urgently needed.

Interconnectedness between periodontitis stage, oral hygiene habits, adherence to the Mediterranean diet and nutritional status in Dalmatian kidney transplant recipients: a cross-sectional study

The aim of this cross-sectional study was to determine the associations between the Mediterranean diet (MeDi), nutritional status parameters, muscle strength, and periodontal status in Dalmatian kidney transplant recipients (KTRs). 89 KTRs were included in this analysis, 40 (45%) women, with a mean age of 61 years (IQR = 13) and a mean time since kidney transplantation of 5 years (IQR = 6.6). An OHIP-14 questionnaire and questionnaire-based periodontal history were obtained from all participants, a comprehensive periodontal examination was performed. Body composition data, anthropometric and clinical parameters were collected for each study participant. The Mediterranean Diet Serving Score (MDSS) was used to assess MeDi adherence, and handgrip strength was measured with a hand dynamometer. Our results showed low adherence to MeDi in KTRs (28%) and almost 50% of KTRs suffer from severe forms of periodontitis. We also found a low OHIP-14 score and poor oral hygiene habits. KTRs with a less severe form of periodontitis had higher muscle mass and handgrip strength. MDSS score was associated with a higher number of teeth, and everyday cereal intake was inversely associated with the periodontitis stage. Our results demonstrate the associations between nutritional status, muscle strength, dietary habits, and periodontal health in Dalmatian KTRs.

Association between Adherence to the Mediterranean Diet and Risk of Type 2 Diabetes: An Updated Systematic Review and Dose-Response Meta-Analysis of Prospective Cohort Studies

Despite earlier meta-analyses on the association between adherence to a Mediterranean diet (MD) and risk of diabetes, there is no comprehensive and updated study assessing this issue. Furthermore, no earlier study has examined the nonlinear dose-response relation between consumption of an MD and risk of diabetes. The current systematic review and meta-analysis was conducted to investigate the linear and nonlinear dose-response relation between MD and incidence of diabetes. Using relevant keywords, electronic searches for prospective studies were conducted in ISI Web of Science, PubMed, and Scopus until January 2022. The reported HRs or ORs in the primary studies were regarded as RRs. The overall effect was calculated using a random-effects model that accounts for between-study variability. The potential nonlinear dose-response associations were tested using a 2-stage hierarchical regression model. Based on 16 prospective studies (with 17 effect sizes), we found that the greatest adherence to the MD was significantly associated with a reduced risk of diabetes (pooled RR: 0.83; 95% CI: 0.77, 0.90; I2 = 79%, P ≤ 0.001). Based on linear dose-response analysis, each 1-score increase in the Mediterranean diet score was associated with a 3% decreased risk of diabetes (HR = 0.97; 95% CI: 0.96, 0.98; P < 0.001). A nonlinear relation (P-nonlinearity = 0.001) was also observed between MD score and risk of type 2 diabetes. Even modest adherence to the MD was linked to a decreased incidence of type 2 diabetes. The protocol is also registered in the International Prospective Register Of Systematic Reviews (PROSPERO) database (https://www.crd.york.ac.uk/PROSPERO/; registration ID: CRD 42021265332).

Ultra-processed foods and risk of all-cause mortality in renal transplant recipients

BACKGROUND

Renal transplant recipients (RTRs) have a 6-fold higher risk of mortality than age- and sex-matched controls. Whether high consumption of ultra-processed foods is associated with survival in RTRs is unknown.

OBJECTIVES

We aimed to study the association between high consumption of ultra-processed foods and all-cause mortality in stable RTRs.

METHODS

We conducted a prospective cohort study in adult RTRs with a stable graft. Dietary intake was assessed using a validated 177-item FFQ. Food items were categorized according to the NOVA classification system and the proportion ultra-processed foods comprised of total food weight per day was calculated.

RESULTS

We included 632 stable RTRs (mean ± SD age: 53.0 ± 12.7 y, 57% men). Mean ± SD consumption of ultra-processed foods was 721 ± 341 g/d (28% of total weight of food intake), whereas the intake of unprocessed and minimally processed foods, processed culinary ingredients, and processed foods accounted for 57%, 1%, and 14%, respectively. During median follow-up of 5.4 y [IQR: 4.9-6.0 y], 129 (20%) RTRs died. In Cox regression analyses, ultra-processed foods were associated with all-cause mortality (HR per doubling of percentage of total weight: 2.13; 95% CI: 1.46, 3.10; P < 0.001), independently of potential confounders. This association was independent from the quality of the overall dietary pattern, expressed by the Mediterranean Diet Score (MDS) or Dietary Approaches to Stop Hypertension (DASH) score. When analyzing ultra-processed foods by groups, only sugar-sweetened beverages (HR: 1.21; 95% CI: 1.05, 1.39; P = 0.007), desserts (HR: 1.24; 95% CI: 1.02, 1.49; P = 0.03), and processed meats (HR: 1.87; 95% CI: 1.22, 2.86; P = 0.004) were associated with all-cause mortality.

CONCLUSIONS

Consumption of ultra-processed foods, in particular sugar-sweetened beverages, desserts, and processed meats, is associated with a higher risk of all-cause mortality after renal transplantation, independently of low adherence to high-quality dietary patterns, such as the Mediterranean diet and the DASH diet.This trial was registered at clinicaltrials.gov as NCT02811835.

Prevention of Post-Transplant Diabetes Mellitus: Towards a Personalized Approach

Post-transplant diabetes is a frequent complication after transplantation. Moreover, patients suffering from post-transplant diabetes have increased cardiovascular morbidity and reduced survival. Pathogenesis mainly involves beta-cell dysfunction in presence of insulin resistance. Both pre- and post-transplant risk factors are well-described, and some of them may be corrected or prevented. However, the frequency of post-transplant diabetes has not decreased in recent years. We realized a critical appraisal of preventive measures to reduce post-transplant diabetes.

Mediterranean dietary pattern and the risk of type 2 diabetes: a systematic review and dose-response meta-analysis of prospective cohort studies

PURPOSE

Previous meta-analyses assessed the association of adherence to the Mediterranean dietary pattern (MedDiet) with the risk of type 2 diabetes (T2D). Since then, new large-scale cohort studies have been published. In addition, dose-response relation was not previously investigated and the certainty of evidence was not assessed. We aimed to explore the dose-response relationship between adherence to the MedDiet and the risk of T2D.

METHODS

We did a systematic search using PubMed, Scopus, and ISI Web of Science upto April 2021 for prospective cohort studies of the relationship between adherence to the MedDiet and the risk of T2D in the general population. The summary relative risks (RR) and 95%CI were estimated by applying a random-effects model.

RESULTS

Fourteen prospective cohort studies (410,303 participants and 41,466 cases) were included. There was an inverse association for the highest versus lowest category of adherence to the MedDiet (RR: 0.79, 95%CI 0.72, 0.88; I² = 82%, n = 14; Risk difference:  - 21 per 1000 person, 95%CI  - 28,  - 12; GRADE = moderate certainty), and for a 2-point increment in the MedDiet adherence score (RR: 0.86, 95%CI 0.82, 0.91; n = 13). The RR remained significant after controlling for important confounders and in almost all subgroups, especially subgroups defined by geographical region. We observed an inverse linear association between MedDiet adherence score and T2D incidence.

CONCLUSION

Adherence to the MedDiet was inversely related to T2D risk in a dose-response manner. Adherence to a Mediterranean-style diet may be a good advice for the primary prevention of T2D.

REGISTRY AND REGISTRY NUMBER

PROSPERO (CRD42021246589).

Nutritional and dietary interventions to prolong renal allograft survival after kidney transplantation

PURPOSE OF REVIEW

Diet plays an important role in slowing progression of chronic kidney disease in native and transplanted kidneys. There is limited evidence on the association on dietary intake with renal allograft function. Mechanisms of major nutrients and dietary patterns with focusing on a plant-based diet related to kidney transplant health and longevity are reviewed.

RECENT FINDINGS

High dietary protein intake may adversely affect renal allograft. Low protein plant-focused diets such as Dietary Approaches to Stop Hypertension, plant-dominant low-protein diet and Mediterranean diets appear associated with favorable outcomes in slowing renal allograft function decline. The mechanism may be related to a change in renal hemodynamic by decreasing glomerular hyperfiltration from low dietary protein intake and plant-based ingredients. Recent observational studies of association between dietary protein intake and kidney allograft outcomes are conflicting. Although strong evidence is still lacking, a low protein diet of 0.6-0.8 g/kg/day with at least 50% of the protein source from plant-based components in kidney transplant recipients with stable kidney allograft function should be considered as the dietary target.

SUMMARY

Dietary intervention with low-protein plant-focused meals may improve outcomes in kidney transplant recipients, but the evidence remains limited and further studies are warranted.

Associations between Depression, Nutritional Status and Mediterranean Diet in Dalmatian Kidney Transplant Recipients

Depression has been addressed as a predictor of worse outcomes in kidney transplant recipients (KTRs). Nutritional status plays a great role in treatment of this population. The Mediterranean diet (MeDi) has been associated with lower levels of depressive symptoms. The aim of this cross-sectional study was to determine the rate of depression and its correlations to nutritional status and dietary habits according to the MeDi in Dalmatian KTRs. We included 115 KTRs, and data about body composition and anthropometric, laboratory and clinical parameters were obtained for each study participant. The Beck Depression Inventory-II (BDI-II) questionnaire was used to assess depressive symptoms and the Mediterranean Diet Serving Score (MDSS) was used to assess adherence to the MeDi. We found the presence of depressive symptoms in 21.73% of the Dalmatian KTRs. BDI-II score was reciprocally associated with fat mass, trunk visceral fat, anthropometric parameters of obesity, triglyceride levels and olive oil consumption. Inverse associations were found between BDI-II score and skeletal muscle mass, handgrip strength, MCV, hemoglobin levels and consumption of fish and white meat, as suggested by the MeDi. Our results showed the interconnections between nutritional status, dietary habits and depression in Dalmatian KTRs.

Polyphenols and Novel Insights Into Post-kidney Transplant Complications and Cardiovascular Disease: A Narrative Review

Kidney transplantation is the preferred treatment for end-stage kidney disease. It is, however, not devoid of complications. Delayed graft function related to ischemia-reperfusion injury (IRI), calcineurin inhibitor (CNI) nephrotoxicity, diabetes, and a particularly high-rate cardiovascular disease (CVD) risk, represent important complications following kidney transplantation. Oxidative stress and chronic low-grade inflammation are mechanisms of disease incompletely abrogated in stable kidney transplant recipient (KTR), contributing to the occurrence of these complications. Polyphenols, bioactive compounds with recognized antioxidant and anti-inflammatory properties have been strongly associated with prevention of CVD in the general population and have been shown to decrease IRI and antagonize CNI nephrotoxicity in animal experimental models, therefore they may have a role in prevention of complications in KTR. This narrative review aims to summarize and discuss current evidence on different polyphenols for prevention of complications, particularly prevention of CVD in KTR, pointing toward the need of further studies with potential clinical impact.

Novel management of diabetes in kidney transplantation

PURPOSE OF REVIEW

Posttransplant diabetes mellitus (PTDM) is a prevalent complication in kidney transplant recipients, and has been associated with worse short-term and long-term outcomes.

RECENT FINDINGS

While hyperglycemia is frequently seen in the early posttransplant period because of surgical stress, infection, and use of high-dose steroids, the diagnosis of PTDM should be established after patients are clinically stable and on stable maintenance immunosuppression. In the early posttransplant period, hyperglycemia is typically treated with insulin, and pilot data have suggested potential benefit of lower vs. higher glycemic targets in this setting. Growing data indicate lifestyle modifications, including dietary interventions, physical activity, and mitigation of obesity, are associated with improved posttransplant outcomes. While there are limited data to support a first-line antidiabetic medication for PTDM, more established pharmacotherapies such as sulfonylureas, meglitinides, and dipetidyl peptidase IV inhibitors are commonly used. Given recent trials showing the benefits of sodium-glucose cotransporter 2 inhibitors and glucagon-like peptide 1 receptor agonists upon kidney outcomes in nontransplant patients, further study of these agents specifically in kidney transplant recipients are urgently needed.

SUMMARY

Increasing evidence supports a multidisciplinary approach, including lifestyle modification, obesity treatment, judicious immunosuppression selection, and careful utilization of novel antidiabetic therapies in PTDM patients.

A Qualitative Study of Clinician Barriers and Enablers to Implementing the Mediterranean Dietary Pattern with Kidney and Liver Transplant Recipients

INTRODUCTION

Solid organ transplant recipients experience greater cardiometabolic risk than the general population. Following a Mediterranean dietary pattern has been shown to reduce cardiometabolic risk. This study aimed to assess multidisciplinary clinician perspectives of routine nutrition care for kidney and liver transplant recipients and barriers and enablers to implementation of the Mediterranean dietary pattern.

METHODS

Semi-structured individual interviews were conducted with clinicians in a metropolitan health service at tertiary/quaternary transplant centres involved in longer-term management of kidney and liver transplants recipients. Audio-recorded interviews were transcribed verbatim and analysed using thematic content analysis.

FINDINGS

Nineteen clinicians (9 medical officers, 5 dietitians, 3 nurses and 2 other allied health professionals) were interviewed. Four themes with 11 subthemes were identified: the Mediterranean dietary pattern is not part of routine care (there are competing clinical priorities; healthy eating principles aligned with but not the full dietary pattern are recommended); variation in knowledge and acceptance of this dietary approach (variances in information sources and degree of knowledge of Mediterranean dietary pattern clinical evidence); nutrition advice is influenced by service delivery and culture (there is lack of consistent nutrition advice; limited consultation time; and reliance on existing patient education resources); and patient-centred care influences decisions on nutrition advice (clinicians do not know how to recommend this dietary pattern in a patient-centred manner).

DISCUSSION

The Mediterranean dietary pattern is not considered part of routine post-transplant nutrition care. To be implemented in these services intervention strategies which address the identified barriers and potential enablers need to be considered.

Diabetes mellitus in dialysis and renal transplantation

Diabetes mellitus is the commonest cause of end-stage kidney failure worldwide and is a proven and significant risk factor for the development of cardiovascular disease. Renal impairment has a significant impact on the physiology of glucose homeostasis as it reduces tissue sensitivity to insulin and reduces insulin clearance. Renal replacement therapy itself affects glucose control: peritoneal dialysis may induce hyperglycaemia due to glucose-rich dialysate and haemodialysis often causes hypoglycaemia due to the relatively low concentration of glucose in the dialysate. Autonomic neuropathy which is common in chronic kidney disease (CKD) and diabetes increases the risk for asymptomatic hypoglycaemia. Pharmacological options for improving glycaemic control are limited due to alterations to drug metabolism. Impaired glucose tolerance and diabetes are also common in the post-kidney-transplant setting and increase the risk of graft failure and mortality. This review seeks to summarise the literature and tackle the intricacies of glycaemic management in patients with CKD who are either on maintenance haemodialysis or have received a kidney transplant. It outlines changes to glycaemic targets, monitoring of glycaemic control, the use of oral hypoglycaemic agents, the management of severe hyperglycaemia in dialysis and kidney transplantation patients.

Dietary interventions on the prevention and management of diabetes in post-kidney transplantation - A systematic review

Post-transplant diabetes mellitus is associated with long-term immunosuppression and weight gain, and is related to an increased risk of cardiovascular disease, accelerated loss of graft and increased mortality. There is an absence of strong evidence-based dietary guidelines for the prevention and management of post-transplant diabetes mellitus in kidney transplant recipients. The aim of this study was to systematically review all dietary evidence for kidney transplant recipients on clinical outcomes relating to diabetes, patient-reported outcomes and economic outcomes. A comprehensive literature search was conducted in August 2020 using the databases Medline, Embase, CENTRAL and CINAHL. Studies were critically appraised using Cochrane risk of bias tools and GRADE. A total of 12 studies and 1928 participants were included. Four papers focused on diet and exercise, one paper on diet only, two papers on magnesium supplementation, one paper on magnesium and fibre intake, two papers on Mediterranean diet, one paper on marine n-3 fatty acid supplementation and one paper on fruit and vegetable intake. There were no significant effects on outcomes relating to dietary counselling, magnesium supplementation, magnesium and fibre intake or marine n-3 fatty acid supplementation. Low-quality evidence supports the Mediterranean diet in reducing the risk of post-transplant diabetes mellitus and fasting plasma glucose levels. Low-quality evidence suggests vegetable intake being associated with a lower risk of post-transplant diabetes mellitus. This review demonstrates limited evidence for dietary interventions in the prevention and management of diabetes in post-kidney transplantation. The findings suggest that further high-quality research with robust study designs is required.

Mediterranean Diet Adherence and Nutritional Status in Dalmatian Kidney Transplant Recipients-Are They Related?

The aim of this study was to evaluate adherence to Mediterranean diet (MeDi) and possible correlation of MeDi adherence and nutritional status parameters in Dalmatian kidney transplant recipients (KTRs). One hundred and sixteen KTRs were included in this study. Data about Mediterranean Diet Serving Score (MDSS), body mass composition, anthropometric parameters, clinical and laboratory parameters were collected for each study participant. The results showed 25% adherence to the MeDi in Dalmatian KTRs. MDSS showed association with higher serum albumin and phosphorus level and higher skeletal muscle mass. Also, significant association between diabetic status and MDSS was found. Adherence to olive oil intake suggested by the MeDi showed significant association with lower level of triglycerides and adherence to nuts suggestions was associated with lower level of fat mass. Following MeDi recommendations for consumption of other foods (cereals, potato, eggs, vegetables, fruits and dairy) were also associated with body mass composition parameters and laboratory findings. In conclusion, low adherence to the MeDi in Dalmatian KTRs raises high concerns. The results showed that MeDi can have favorable effects on nutritional status in KTRs. A structured nutritional approach is needed to enhance adherence to the MeDi and prevent possible adverse effects in this patient population.

Metabolic syndrome-related dietary pattern and risk of mortality in kidney transplant recipients

BACKGROUND AND AIMS

Presence of the metabolic syndrome (MetS) importantly contributes to excess mortality in kidney transplant recipients (KTRs). However, it is unclear which dietary factors drive the adverse role of MetS in KTRs. We aimed to define a dietary pattern that maximally explained the variation in MetS components, and to investigate the association between this MetS-related dietary pattern (MetS-DP) and all-cause mortality in KTRs.

METHODS AND RESULTS

We included 429 adult KTRs who had a functioning graft ⩾1 year. A MetS-DP was constructed using habitual dietary intake derived from a 177-item food frequency questionnaire. We used reduced rank regression (RRR), and defined the six components of MetS (waist circumference, systolic blood pressure, diastolic blood pressure, serum triglycerides, HbA1c, and HDL cholesterol) as response variables and 48 food groups as predictor variables. We evaluated the association between the MetS-DP and all-cause mortality using multivariable Cox regression analysis. The MetS-DP was characterized by high intakes of processed meat and desserts, and low intakes of vegetables, tea, rice, fruits, milk, and meat substitutes. During a mean follow-up of 5.3 ± 1.2 years, 63 KTRs (14.7%) died. Compared to the lowest tertile of the Mets-DP score, those with the greatest adherence had a more than 3-fold higher risk of all-cause mortality (hazard ratio [HR] = 3.63; 95% confidence interval [CI], 1.70-7.74, P < 0.001), independent of potential confounders.

CONCLUSIONS

We identified a MetS-related dietary pattern which was independently associated with all-cause mortality in KTRs. The association between this dietary pattern and all-cause mortality was mediated by MetS. Clinical trial reg. no. NCT02811835.

Modelling the Cost-Effectiveness of Implementing a Dietary Intervention in Renal Transplant Recipients

Background: The Dietary Approach to Stop Hypertension (DASH) and potassium supplementation have been shown to reduce the risk of death with a functioning graft (DWFG) and renal graft failure in renal transplant recipients (RTR). Unfortunately, a key problem for patients is the adherence to these diets. The aim of this study is to evaluate the cost-effectiveness and budget impact of higher adherence to either the DASH or potassium supplementation. Methods: A Markov model was used to simulate the life course of 1000 RTR in the Netherlands. A societal perspective with a lifetime time horizon was used. The potential effect of improvement of dietary adherence was modelled in different scenarios. The primary outcomes are the incremental cost-effectiveness ratio (ICER) and the budget impact. Results: In the base case, improved adherence to the DASH diet saved 27,934,786 and gained 1880 quality-adjusted life years (QALYs). Improved adherence to potassium supplementation saved €1,217,803 and gained 2901 QALYs. Both resulted in dominant ICERs. The budget impact over a five-year period for the entire Dutch RTR population was €8,144,693. Conclusion: Improving dietary adherence in RTR is likely to be cost-saving and highly likely to be cost-effective compared to the current standard of care in the Netherlands.

Current Pharmacological Intervention and Medical Management for Diabetic Kidney Transplant Recipients

Hyperglycemia after kidney transplantation is common in both diabetic and non-diabetic patients. Both pretransplant and post-transplant diabetes mellitus are associated with increased kidney allograft failure and mortality. Glucose management may be challenging for kidney transplant recipients. The pathophysiology and pattern of hyperglycemia in patients following kidney transplantation is different from those with type 2 diabetes mellitus. In patients with pre-existing and post-transplant diabetes mellitus, there is limited data on the management of hyperglycemia after kidney transplantation. The following article discusses the nomenclature and diagnosis of pre- and post-transplant diabetes mellitus, the impact of transplant-related hyperglycemia on patient and kidney allograft outcomes, risk factors and potential pathogenic mechanisms of hyperglycemia after kidney transplantation, glucose management before and after transplantation, and modalities for prevention of post-transplant diabetes mellitus.

Metabolic Consequences of Solid Organ Transplantation

Metabolic complications affect over 50% of solid organ transplant recipients. These include posttransplant diabetes, nonalcoholic fatty liver disease, dyslipidemia, and obesity. Preexisting metabolic disease is further exacerbated with immunosuppression and posttransplant weight gain. Patients transition from a state of cachexia induced by end-organ disease to a pro-anabolic state after transplant due to weight gain, sedentary lifestyle, and suboptimal dietary habits in the setting of immunosuppression. Specific immunosuppressants have different metabolic effects, although all the foundation/maintenance immunosuppressants (calcineurin inhibitors, mTOR inhibitors) increase the risk of metabolic disease. In this comprehensive review, we summarize the emerging knowledge of the molecular pathogenesis of these different metabolic complications, and the potential genetic contribution (recipient +/- donor) to these conditions. These metabolic complications impact both graft and patient survival, particularly increasing the risk of cardiovascular and cancer-associated mortality. The current evidence for prevention and therapeutic management of posttransplant metabolic conditions is provided while highlighting gaps for future avenues in translational research.

Food Literacy Is Associated With Adherence to a Mediterranean-Style Diet in Kidney Transplant Recipients

OBJECTIVES

Adherence to a Mediterranean-style diet is associated with improved health outcomes in kidney transplant recipients (KTR). However, poor dietary habits, including excessive sodium intake, are common in KTR, indicating difficulties with incorporating a healthy diet into daily life. Food literacy is identified as potential facilitator of a healthy diet, but the precise relationship between food literacy and dietary intake in KTR has not been investigated. This study examined food literacy levels in KTR and its association with adherence to a Mediterranean-style diet and sodium intake.

METHODS

This cross-sectional study is part of the TransplantLines Cohort and Biobank Study. Food literacy was measured with the Self-Perceived Food Literacy (SPFL) questionnaire. Dietary intake assessment with food frequency questionnaires was used to calculate the Mediterranean Diet Score. Sodium intake was based on the 24-hour urinary sodium excretion rate. Associations of SPFL with Mediterranean Diet Score and sodium intake were assessed with univariable and multivariable linear regression analyses.

RESULTS

In total, 148 KTR (age 56 [48-66]; 56% male) completed the SPFL questionnaire with a mean SPFL score of 3.63 ± 0.44. Higher SPFL was associated with a higher Mediterranean Diet Score in KTR (β = 1.51, 95% confidence interval 0.88-2.12, P ≤ .001). Although KTR with higher food literacy tended to have a lower sodium intake than those with lower food literacy (P = .08), the association of food literacy with sodium intake was not significant in a multivariable regression analysis (β = 0.52 per 10 mmol/24-hour increment, 95% confidence interval -1.79 to 2.83, P = .66).

CONCLUSIONS

Higher levels of food literacy are associated with better adherence to a Mediterranean-style diet in KTR. No association between food literacy and sodium intake was found. Further studies are needed to determine if interventions on improving food literacy contribute to a healthier diet and better long-term outcomes in KTR.

Patients' Experiences of Life Challenges After Liver Transplantation: A Qualitative Study

Patients experience a new life with different challenges after liver transplantation (LT). Identifying these challenges can facilitate the improvement of their quality of life. This study aimed to explore patients’ experiences of post-LT life challenges. This qualitative study was performed in 2019 through the content analysis approach. Participants were liver transplant recipients purposively recruited from a LT clinic. Semistructured interviews were conducted for data collection. Data were analyzed through Graneheim and Lundman’s conventional content analysis approach. Meaning units were identified and coded, and the codes were grouped into subcategories and categories according to their similarities. In total, 18 transplant recipients were interviewed. Their age mean was 51 years and their transplant age ranged from 4 months to 12 years. Their post-LT life challenges were categorized into 4 main categories, that is, self-care deficit, the need for seeking information, fears and concerns, and hope–despair duality. Nurses and members of LT team are recommended to assess transplant recipients’ life challenges and develop comprehensive plans for managing their challenges and problems and improving their quality of life.

Organ donation and transplantation: a multi-stakeholder call to action

Although overall donation and transplantation activity is higher in Europe than on other continents, differences between European countries in almost every aspect of transplantation activity (for example, in the number of transplantations, the number of people with a functioning graft, in rates of living versus deceased donation, and in the use of expanded criteria donors) suggest that there is ample room for improvement. Herein we review the policy and clinical measures that should be considered to increase access to transplantation and improve post-transplantation outcomes. This Roadmap, generated by a group of major European stakeholders collaborating within a Thematic Network, presents an outline of the challenges to increasing transplantation rates and proposes 12 key areas along with specific measures that should be considered to promote transplantation. This framework can be adopted by countries and institutions that are interested in advancing transplantation, both within and outside the European Union. Within this framework, a priority ranking of initiatives is suggested that could serve as the basis for a new European Union Action Plan on Organ Donation and Transplantation.

Physical Activity and the Development of Post-Transplant Diabetes Mellitus, and Cardiovascular- and All-Cause Mortality in Renal Transplant Recipients

(1) Background: Little is currently known about the health impacts of daily-life moderate-to-vigorous physical activity (MVPA) in relation to the development of post-transplant diabetes mellitus (PTDM) and the long-term survival of renal transplant recipients (RTRs). (2) Methods: We analyzed self-reported data on MVPA within non-occupational and occupational domains, estimated with the SQUASH questionnaire, from a prospective cohort study of RTRs (n = 650) with a functioning graft exceeding 1 year. PTDM diagnoses were based on plasma glucose levels (≥126 mg/dL), HbA1c (≥6.5%), and the use of antidiabetic medication. Mortality data were retrieved from patient files up to the end of September 2015. (3) Results: During a median follow-up period of 5.3 years, 50 patients (10%) developed PTDM and 129 (19.8%) died. Of these deaths, 53 (8.9%) were caused by cardiovascular disease. Cox regression analyses showed that higher MVPA levels among patients were associated with a lower risk of PTDM (hazard ratio (HR); 95% confidence interval (95%CI) = 0.49; 0.25–0.96, p = 0.04), cardiovascular- (0.34; 0.15–0.77, p = 0.01), and all-cause mortality (0.37; 0.24–0.58, p < 0.001) compared with No-MVPA patients, independently of age, sex, and kidney function parameters. Associations of MVPA with cardiovascular and all-cause mortality remained significant and materially unchanged following further adjustments made for transplant characteristics, lifestyle factors, metabolic parameters, medication use, and creatinine excretion (muscle mass). However, the association between MVPA and PTDM was no longer significant after we adjusted for metabolic confounders and glucose levels. (4) Conclusion: Higher MVPA levels are associated with long-term health outcomes in RTRs.

Mediterranean Style Diet and Kidney Function Loss in Kidney Transplant Recipients

BACKGROUND AND OBJECTIVES

Despite improvement of short-term graft survival over recent years, long-term graft survival after kidney transplantation has not improved. Studies in the general population suggest the Mediterranean diet benefits kidney function preservation. We investigated whether adherence to the Mediterranean diet is associated with kidney outcomes in kidney transplant recipients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We included 632 adult kidney transplant recipients with a functioning graft for ≥1 year. Dietary intake was inquired using a 177-item validated food frequency questionnaire. Adherence to the Mediterranean diet was assessed using a nine-point Mediterranean Diet Score. Primary end point of the study was graft failure and secondary end points included kidney function decline (doubling of serum creatinine or graft failure) and graft loss (graft failure or death with a functioning graft). Cox regression analyses were used to prospectively study the associations of the Mediterranean Diet Score with study end points.

RESULTS

During median follow-up of 5.4 (interquartile range, 4.9-6.0) years, 76 participants developed graft failure, 119 developed kidney function decline, and 181 developed graft loss. The Mediterranean Diet Score was inversely associated with all study end points (graft failure: hazard ratio [HR], 0.68; 95% confidence interval [95% CI], 0.50 to 0.91; kidney function decline: HR, 0.68; 95% CI, 0.55 to 0.85; and graft loss: HR, 0.74; 95% CI, 0.63 to 0.88 per two-point increase in Mediterranean Diet Score) independent of potential confounders. We identified 24-hour urinary protein excretion and time since transplantation to be an effect modifier, with stronger inverse associations between the Mediterranean Diet Score and kidney outcomes observed in participants with higher urinary protein excretion and participants transplanted more recently.

CONCLUSIONS

Adherence to the Mediterranean diet is associated with better kidney function outcomes in kidney transplant recipients.

Barriers and Facilitators of Fruit and Vegetable Consumption in Renal Transplant Recipients, Family Members and Healthcare Professionals-A Focus Group Study

Low fruit and vegetable consumption is associated with poor outcomes after renal transplantation. Insufficient fruit and vegetable consumption is reported in the majority of renal transplant recipients (RTR). The aim of this study was to identify barriers and facilitators of fruit and vegetable consumption after renal transplantation and explore if certain barriers and facilitators were transplant-related. After purposive sampling, RTR (n = 19), their family members (n = 15) and healthcare professionals (n = 5) from a Dutch transplant center participated in seven focus group discussions (three each for RTR and family members, one with healthcare professionals). Transcripts were analyzed using social cognitive theory as conceptual framework and content analysis was used for identification of themes. Transplant-related barriers and facilitators were described separately. In categorizing barriers and facilitators, four transplant-related themes were identified: transition in diet (accompanied by, e.g., fear or difficulties with new routine), physical health (e.g., recovery of uremic symptoms), medication (e.g., cravings by prednisolone) and competing priorities after transplantation (e.g., social participation activities). Among the generic personal and environmental barriers and facilitators, food literacy and social support were most relevant. In conclusion, transplant-related and generic barriers and facilitators were identified for fruit and vegetable consumption in RTR. The barriers that accompany the dietary transition after renal transplantation may contribute to the generally poorer fruit and vegetable consumption of RTR. These findings can be used for the development of additional nutritional counseling strategies in renal transplant care.

Vitamin B12 status in kidney transplant recipients: association with dietary intake, body adiposity and immunosuppression

The aim of the present study was to evaluate the prevalence of vitamin B12 (B12) deficiency in kidney transplant recipients (KTR) and its possible association with B12 dietary intake, body adiposity and immunosuppressive drugs. In this cross-sectional study, we included 225 KTR, aged 47·50 (sd 12·11) years, and 125 (56 %) were men. Serum levels of B12 were determined by chemiluminescent microparticle intrinsic factor assay and the cut-off of 200 pg/ml was used to stratify KTR into B12-sufficient or B12-deficient group. B12 dietary intake was evaluated by three 24 h dietary recalls and was considered adequate when ≥2·4 μg/d. Body adiposity was estimated after taking anthropometric measures and using the dual-energy X-ray absorptiometry (DXA) method. B12 deficiency was seen in 14 % of the individuals. B12-deficient group, compared with the B12-sufficient group, exhibited lower intake of B12 (median 2·42 (interquartile range (IQR) 1·41-3·23) v. 3·16 (IQR 1·94-4·55) μg/d, P = 0·04) and higher values of waist circumference (median 96·0 (IQR 88·0-102·5) v. 90·0 (IQR 82·0-100·0) cm, P = 0·04). When the analysis included only women, B12 deficiency was associated with higher total and central body adiposity measurements obtained with anthropometry (BMI, body adiposity index, waist and neck circumferences) and DXA (total and trunk body fat). Among individuals with adequate intake of B12, the deficiency of this vitamin was more frequently seen in those using mycophenolate mofetil (MMF) (17 %) v. azathioprine (2 %), P = 0·01. In conclusion, the prevalence of B12 deficiency in KTR was estimated as 14 % and was associated with reduced intake of B12 as well as higher adiposity, especially in women, and with the use of MMF.

Plasma Malondialdehyde and Risk of New-Onset Diabetes after Transplantation in Renal Transplant Recipients: A Prospective Cohort Study

New-onset diabetes after transplantation (NODAT) is a frequent complication in renal transplant recipients (RTR). Although oxidative stress has been associated with diabetes mellitus, data regarding NODAT are limited. We aimed to prospectively investigate the long-term association between the oxidative stress biomarker malondialdehyde (measured by high-performance liquid chromatography) and NODAT in an extensively phenotyped cohort of non-diabetic RTR with a functioning graft ≥1 year. We included 516 RTR (51 ± 13 years-old, 57% male). Median plasma malondialdehyde (MDA) was 2.55 (IQR, 1.92-3.66) µmol/L. During a median follow-up of 5.3 (IQR, 4.6-6.0) years, 56 (11%) RTR developed NODAT. In Cox proportional-hazards regression analyses, MDA was inversely associated with NODAT, independent of immunosuppressive therapy, transplant-specific covariates, lifestyle, inflammation, and metabolism parameters (HR, 0.55; 95% CI, 0.36-0.83 per 1-SD increase; p < 0.01). Dietary antioxidants intake (e.g., vitamin E, α-lipoic acid, and linoleic acid) were effect-modifiers of the association between MDA and NODAT, with particularly strong inverse associations within the subgroup of RTR with relatively higher dietary antioxidants intake. In conclusion, plasma MDA concentration is inversely and independently associated with long-term risk of NODAT in RTR. Our findings support a potential underrecognized role of oxidative stress in post-transplantation glucose homeostasis.

Dietary Approach to Stop Hypertension (DASH) diet and risk of renal function decline and all-cause mortality in renal transplant recipients

Renal transplant recipients (RTR) are at risk of decline of graft function and premature mortality, with high blood pressure as an important risk factor for both. To study the association of the Dietary Approach to Stop Hypertension (DASH) diet with these adverse events, we conducted a prospective cohort study of adult RTR. Dietary data were collected using a validated 177-item food frequency questionnaire and an overall DASH-score was obtained. We included 632 stable RTR (mean ± standard deviation age 53.0 ± 12.7 years, 57% men). Mean DASH score was 23.8 ± 4.7. During median follow-up of 5.3 (interquartile range, 4.1-6.0) years, 119 (18.8%) RTR had renal function decline, defined as a combined endpoint of doubling of serum creatinine and death-censored graft failure, and 128 (20.3%) died. In Cox-regression analyses, RTR in the highest tertile of the DASH score had lower risk of both renal function decline (hazard ratio [HR] = 0.57; 95% confidence interval [CI], 0.33-0.96, P = .03) and all-cause mortality (HR = 0.52; 95%CI, 0.32-0.83, P = .006) compared to the lowest tertile, independent of potential confounders. Adherence to a DASH-style diet is associated with lower risk of both renal function decline and all-cause mortality. These results suggest that a healthful diet might benefit long-term outcome in RTR.

Post-transplantation diabetes in kidney transplant recipients: an update on management and prevention

Post-transplantation diabetes mellitus (PTDM) may severely impact both short- and long-term outcomes of kidney transplant recipients in terms of graft and patient survival. However, PTDM often goes undiagnosed is underestimated or poorly managed. A diagnosis of PTDM should be delayed until the patient is on stable maintenance doses of immunosuppressive drugs, with stable kidney graft function and in the absence of acute infections. Risk factors for PTDM should be assessed during the pre-transplant evaluation period, in order to reduce the likelihood of developing diabetes. The oral glucose tolerance test is considered as the gold standard for diagnosing PTDM, whereas HbA1c is not reliable during the first months after transplantation. Glycaemic targets should be individualised, and comorbidities such as dyslipidaemia and hypertension should be treated with drugs that have the least possible impact on glucose metabolism, at doses that do not interact with immunosuppressants. While insulin is the preferred agent for treating inpatient hyperglycaemia in the immediate post-transplantation period, little evidence is available to guide therapeutic choices in the management of PTDM. Metformin and incretins may offer some advantage over other glucose-lowering agents, particularly with respect to risk of hypoglycaemia and weight gain. Tailoring immunosuppressive regimens may be of help, although maintenance of good kidney function should be prioritised over prevention/treatment of PTDM. The aim of this narrative review is to provide an overview of the available evidence on management and prevention of PTDM, with a focus on the available therapeutic options.

Renal sulfate reabsorption in healthy individuals and renal transplant recipients

Inorganic sulfate is essential for normal cellular function and its homeostasis is primarily regulated in the kidneys. However, little is known about renal sulfate handling in humans and particularly in populations with impaired kidney function such as renal transplant recipients (RTR). Hence, we aimed to assess sulfate reabsorption in kidney donors and RTR. Plasma and urinary sulfate were determined in 671 RTR and in 251 kidney donors. Tubular sulfate reabsorption (TSR) was defined as filtered load minus sulfate excretion and fractional sulfate reabsorption (FSR) was defined as 1-fractional excretion. Linear regression analyses were employed to explore associations of FSR with baseline parameters and to identify the determinants of FSR in RTR. Compared to kidney donors, RTR had significantly lower TSR (15.2 [11.2-19.5] vs. 20.3 [16.7-26.3] μmol/min), and lower FSR (0.56 [0.48-0.64] vs. 0.64 [0.57-0.69]) (all P < 0.001). Kidney donation reduced both TSR and FSR by circa 50% and 25% respectively (both P < 0.001). In RTR and donors, both TSR and FSR associated positively with renal function. In RTR, FSR was independently associated with urinary thiosulfate (β = -0.18; P = 0.002), growth hormone (β = 0.12; P = 0.007), the intakes of alcohol (β = -0.14; P = 0.002), methionine (β = -0.34; P < 0.001), cysteine (β = -0.41; P < 0.001), and vitamin D (β = -0.14; P = 0.009). In conclusion, TSR and FSR are lower in RTR compared to kidney donors and both associated with renal function. Additionally, FSR is determined by various dietary and metabolic factors. Future research should determine the mechanisms behind sulfate handling in humans and the prognostic value of renal sulfate reabsorption in RTR.

Lifestyle intervention to improve quality of life and prevent weight gain after renal transplantation: Design of the Active Care after Transplantation (ACT) randomized controlled trial

BACKGROUND

Low physical activity and reduced physical functioning are common after renal transplantation, resulting in a reduced quality of life. Another common post-transplantation complication is poor cardio-metabolic health, which plays a main role in long-term outcomes in renal transplant recipients (RTR). It is increasingly recognized that weight gain in the first year after transplantation, especially an increase in fat mass, is a highly common contributor to cardio-metabolic risk. The aim of this study is to compare the outcomes of usual care to the effects of exercise alone, and exercise combined with dietary counseling, on physical functioning, quality of life and post-transplantation weight gain in RTR.

METHODS

The Active Care after Transplantation study is a multicenter randomized controlled trial with three arms in which RTR from 3 Dutch hospitals are randomized within the first year after transplantation to usual care, to exercise intervention (3 months supervised exercise 2 times per week followed by 12 months active follow-up), or to an exercise + diet intervention, consisting of the exercise training with additional dietary counseling (12 sessions over 15 months by a renal dietician). In total, 219 participants (73 per group) will be recruited. The primary outcome is the subdomain physical functioning of quality of life, (SF-36 PF). Secondary outcomes include other evaluations of quality of life (SF-36, KDQOL-SF, EQ-5D), objective measures of physical functioning (aerobic capacity and muscle strength), level of physical activity, gain in adiposity (body fat percentage by bio-electrical impedance assessment, BMI, waist circumference), and cardiometabolic risk factors (blood pressure, lipids, glucose metabolism). Furthermore, data on renal function, medical history, medication, psychological factors (motivation, kinesiophobia, coping style), nutrition knowledge, nutrition intake, nutrition status, fatigue, work participation, process evaluation and cost-effectiveness are collected.

DISCUSSION

Evidence on the effectiveness of an exercise intervention, or an exercise + diet intervention on physical functioning, weight gain and cardiometabolic health in RTR is currently lacking. The outcomes of the present study may help to guide future evidence-based lifestyle care after renal transplantation.

TRIAL REGISTRATION

Number: NCT01047410 .