Effect of age and dialysis vintage on obesity paradox in long-term hemodialysis patients

Association of Frailty with Postoperative Survival and Outcomes Following Hemodialysis Vascular Access Creation

BACKGROUND

The literature suggests that for patients to experience the purported advantages of an arteriovenous fistula (AVF) over arteriovenous graft (AVG), a minimum survival of 18 months is required. With the vascular access guideline shift away from "Fistula First" toward shared decision making, patient survival after vascular access creation is a major factor to consider in optimal access selection. The objective of this study is to examine outcomes of vascular access in patients with short survival and factors associated with short survival, including frailty.

METHODS

We performed a retrospective review of 200 access procedures performed between August 2018 and November 2020 at a single institution. Maturation was defined as the date when the surgeon deemed the access ready to be used for dialysis. A modified Risk Analysis Index (RAI) score was used to calculate frailty.

RESULTS

Within 3 years after access creation, 55 (27.5%) patients were recorded as dead (mortality within 3 years of access creation [3YMORT]). In the 3YMORT group, 5 did not follow-up with the surgeon prior to death and 22/34 (65%) of AVF versus 15/16 (94%) of AVGs were deemed mature prior to death (P = 0.03). Of the accesses that matured, the median days to maturation for AVF was 69 (interquartile range [IQR] 53, 87) versus 28 (IQR 18, 32) for AVG (P < 0.001). Patients in the 3YMORT group were older (70.6 vs. 63.4, P = 0.004) and had a lower body mass index (24.8 vs. 27.4, P = 0.03). Patients in the 3YMORT group had higher prevalence of dysrhythmia (35% vs. 15%, P = 0.002), chronic obstructive pulmonary disorder (20% vs. 10%, P = 0.048) and dialysis dependence at the time of access creation (91% vs. 75%, P = 0.01). There was no significant difference in sex, white race, Hispanic ethnicity, coronary artery disease, congestive heart failure, previous coronary artery bypass graft or percutaneous coronary intervention, diabetes, hypertension, and peripheral arterial disease between the 2 groups. The 3YMORT group had a significantly higher prevalence of frailty (78% vs. 49%, P = 0.0002). Patients categorized as frail by the RAI had a significantly higher risk of 3YMORT (odds ratio [OR] 3.74, 95% confidence interval [CI] 1.82-7.66) compared to nonfrail patients. Patients categorized as very frail by the RAI had an even higher risk of 3YMORT (OR 4.20, 95% CI 1.95-9.05), compared to nonfrail patients.

CONCLUSIONS

Patients with short life expectancy after vascular access creation may have high rates of AVF nonmaturation and longer time to maturation. Factors associated with high risk of mortality within 3 years of vascular access creation correlate well with factors included in the RAI frailty score. Patients who are frail or very frail may be appropriate candidates for AVG creation over AVF considering their high risk for short life expectancy.

Obesity-associated Inflammation and Alloimmunity

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

Early Detection of Inflammation and Malnutrition and Prediction of Acute Events in Hemodialysis Patients through PINI (Prognostic Inflammatory and Nutritional Index)

Protein-energy wasting and inflammation are major risk factors for complications in hemodialysis patients. As these risk factors are triggered by a pro-inflammatory state, oxidative stress and hemodynamic dysfunction, which overlap in hemodialyzed subjects, we aimed to assess the efficacy of a cost-effective and straightforward screening tool, the Prognostic Inflammatory and Nutritional Index (PINI), in regularly screening maintenance hemodialysis (MHD) patients, to detect early signs of inflammation and malnutrition. A 12-month follow-up was carried out on a cohort of 102 adult patients undergoing maintenance dialysis, during which the Prognostic Inflammatory and Nutritional Index (PINI) was calculated using the formula alpha1-Acid Glycoprotein (AGP) × C-reactive protein (CRP)/albumin (ALB) × transthyretin (TTR). A PINI score < 1 was considered normal. The patients were stratified based on their PINI score: 66 patients (64.70%) had a normal score, below 1, while 36 patients (35.30%) had a PINI score ≥ 1. Despite the absence of clinical evidence of inflammation at enrollment, the latter group exhibited higher levels of CRP. During the follow-up period, all patients with a PINI score ≥ 1 experienced at least one acute event, compared to only 6% of patients with a normal PINI score, which presented COVID-19 infection as an acute event. The evaluation of the PINI can effectively identify the silent malnutrition-inflammation syndrome and predict the risk of acute events. This straightforward test appears to be a rapid tool that is independent of the examiner's experience and subjectivity, thereby potentially reducing hospitalization costs.

[Use of cinacalcet in secondary hyperparathyroidism: assessment of nutritional, lipid and inflammatory status in chronic kidney disease]

Introduction

Introduction: observations in cell lines suggest that the use of cinacalcet could be associated with increase in body fat, inflammatory state, and alteration in lipid metabolism. However, when scaling the model to the clinical level, the occurrence of these effects is unknown. Objectives: to analyze the effect of cinacalcet therapy on anthropometric, inflammatory and lipid parameters in renal patients with secondary hyperparathyroidism (SHPT). Methods: observational study with two approaches. The retrospective study included 89 patients who started cinacalcet treatment since 2018 with a maximum follow-up of 36 months. Body mass index (BMI) variables, waist circumference, tricipital skinfold, parathyroid hormone (PTH), and biochemical profile were analyzed. The prospective study included 52 patients who started cinacalcet treatment since 2020 with a 12-month follow-up. BMI, PTH, lipid profile, and PCR variables were analyzed. Results: in the retrospective study, BMI was 27 kg/m2, with 62 % overweight and 65 % of patients with high cardiovascular risk. Cinacalcet reduced PTH by 12 % after six months (p < 0.01) and serum calcium decreased by 3.4 % at the end of follow-up (p = 0.04). According to the prospective study, BMI was 26.8 kg/m2, with 60 % overweight. PTH decreased by 8.4 % after six months. Total cholesterol, LDL cholesterol, and triglycerides decreased by 6.8 %, 12.5 %, and 5.5 %, respectively, at the end of follow-up. Conclusions: the prevalent nutritional status is excess weight. In patients with SHPT, cinacalcet improves PTH control without causing changes in anthropometric, lipid, and inflammatory parameters.

Clinical Significance of Nutritional Status, Inflammation, and Body Composition in Elderly Hemodialysis Patients-A Case-Control Study

Nutritional and inflammatory disorders are factors that increase the risk of adverse clinical outcomes and mortality in elderly hemodialysis (HD) patients. This study aimed to examine nutritional and inflammation status as well as body composition in older adults on HD compared to matched controls. A case-control study was conducted on 168 older participants (84 HD patients (cases) and 84 controls) age- and sex-matched. Demographic, clinical, anthropometric, and laboratory parameters were collected from medical records. The primary outcome was nutritional status assessment using a combination of nutritional and inflammatory markers along with the geriatric nutritional risk index (GNRI). Sarcopenic obesity (SO) was studied by the combined application of anthropometric measures. Body composition and hydration status were assessed by bioelectrical impedance analysis (BIA). Univariate and multivariate regression analyses were performed to identify nutritional and inflammatory independent risk indicators in elderly HD patients and controls. A significantly high prevalence of nutritional risk measured by the GNRI was found in HD patients (32.1%) compared to controls (6.0%) (p < 0.001). Elderly HD patients were overweight and had lower percent arm muscle circumference, phase angle (PA), serum albumin (s-albumin), as well as higher percent extracellular body water (ECW%) and serum C-reactive protein (s-CRP) than controls (all at least, p < 0.01). SO was higher in HD patients (15.50%) than in controls (14.30%). By multi-regression analyses, age < 75 years (OR: 0.119; 95%CI: 0.036 to 0.388), ECW% (OR: 1.162; 95%CI: 1.061 to 1.273), PA (OR: 0.099; 95%CI: 0.036 to 0.271), as well as BMI, s-albumin ≥ 3.8 g/dL, and lower s-CRP were independently related between cases and controls (all at least, p < 0.05). Elderly HD patients had increased nutritional risk, SO, inflammation, overhydration, and metabolic derangements compared to controls. This study highlights the importance of identifying nutritional risk along with inflammation profile and associated body composition disorders in the nutritional care of elderly HD patients. Further studies are needed to prevent nutritional disorders in elderly HD patients.

Obesity and Kidney Transplantation-How to Evaluate, What to Do, and Outcomes

Obesity is a growing issue that is spreading worldwide; its prevalence is ever increasing in patients with end-stage renal disease and represents a potential barrier to transplantation. The lack of unanimous guidelines exacerbates the current disparity in treatment, which can affect outcomes, leading to a significantly longer time on the waiting list. Multidisciplinary and multimodal management (encompassing several healthcare professionals such as nephrologists, transplant physicians and surgeons, primary care providers, and nurses) is of paramount importance for the optimal management of this patient population in a continuum from waitlisting to transplantation. Development of this guideline followed a standardized protocol for evidence review. In this review, we report on our clinical experience in transplantation of obese patients; strategies to manage this condition, including bariatric surgery, suitable timing for transplantation among this patient population, and clinical experience in robotic sleeve gastrectomy; and simultaneous robotic kidney transplantation to achieve optimal outcomes.

Individualization of the Dosage Regimen of Erythropoietin is Crucial in End-stage Renal Disease Patients

The objective of this study was to understand the utilization pattern of erythropoietin in end-stage renal disease patients, along with the effect of body weight and sex on the patients' responses. In this retrospective single-center study, 120 patients were included who were on a once weekly (n = 79), twice weekly (n = 37), or thrice weekly (n = 4) regimen. The doses of erythropoiesis-stimulating agents (ESA) were collected, and the erythropoietin resistance index (ERI) was determined. The Kruskal-Wallis test was used to evaluate the dose schedules, and the once-weekly regimen produced a greater response (P = 0.001). The asymptotic significance of Pearson's Chi-square-test equating the mean ERI and body mass index (BMI) was 0.034. No statistically significant correlation was estimated between sex and mean ERI (P = 0.201). Our study demonstrated that the once-weekly regimen dominated over the others in terms of efficacy, and individuals with a higher BMI were found to respond better to the ESA therapy.

An investigation of low-protein diets' qualification rates and an analysis of their short-term effects for patients with CKD stages 3-5: a single-center retrospective cohort study from China

BACKGROUND

The feasibility and efficacy of low-protein diets (LPD) treatment in chronic kidney disease (CKD) is controversial. Based on the characteristics of the Chinese diet, we observe the qualification rates and short-term clinical effects of LPD for CKD patients in our center.

METHODS

This is a retrospective cohort study. CKD stages 3-5 patients who were regularly followed up 5 times (over 2 years) and treated with LPD were included. We collected clinical data to observe the changes in LPD qualification rates and divided patients into LPD and non-LPD group according to the average dietary protein intake (DPI) of 5 follow-up time points and compared the changes in primary and secondary outcome measures between the two groups.

RESULTS

We analyzed data from 161 eligible CKD stages 3-5 patients. From baseline to the 5th follow-up time point, the LPD qualification rates of all patients were 11.80%, 35.40%, 47.82%, 53.43% and 54.04%, respectively. For primary outcome measures, the urine protein/creatinine ratio (UPCR) decreased more in the LPD group than in the non-LPD group [Median (interquartile range, IQR) of the difference between the 5th follow-up time point and baseline: 0.19 (- 0.01-0.73) vs. 0.10 (- 0.08-0.27), P < 0.001]. We constructed three classes of mixed linear models (model I, II, III). The UPCR slopes were all negative in the LPD group and positive in the non-LPD group (P < 0.001). Meanwhile, in model I, the estimate glomerular filtration rate(eGFR) decline slope in the LPD group was lower than that in the non-LPD group [slope (standard error): - 1.32 (0.37) vs. - 2.35 (0.33), P = 0.036]. For secondary outcome measures, body mass index (BMI) triglycerides (TG), body weight, and fat free mass (FFM) showed stable statistical differences in the comparison of LPD and non-LPD groups, with greater declines in the former.

CONCLUSION

The results of this study suggest that LPD treatment can reduce UPCR in patients with CKD stages 3-5, and may also delay the decline in eGFR. Meanwhile, it also reduces BMI, TG, body weight, and FFM, thus the need to prevent malnutrition in clinical implementation.

Cardiovascular Risk and Diseases in Patients With and Without Leptin-Melanocortin Pathway Variants

OBJECTIVE

To study differences in cardiovascular risk factors and diseases between patients with and without genetic variants in the leptin-melanocortin pathway.

METHODS

A cross-sectional study of patients with a history of severe obesity genotyped in June 2019 as participants of the Mayo Clinic Biobank was conducted in March 2022 to assess differences in cardiovascular risk and diseases between carriers of a heterozygous variant in the leptin-melanocortin pathway and noncarriers. Cardiovascular risk factors included hypertension, diabetes, dyslipidemia, and smoking. Cardiovascular disease includes coronary artery disease, peripheral artery disease, and cerebrovascular accidents. Patients with a history of bariatric surgery were excluded. We used logistic regression models to estimate the odds ratio and 95% CI, adjusting for age, body mass index (BMI), and sex.

RESULTS

Among a total of 168 carriers (8%; 121 [72%] female; mean [SD] age, 65.1 [14.9] years; BMI, 44.0 [7.4] kg/m2) and 2039 noncarriers (92%; 1446 [71%] female; mean [SD] age, 64.9 [14.4] years; BMI, 42.9 [6.6] kg/m2), carriers had higher prevalence odds of hypertension (odds ratio, 3.26; 95% CI, 2.31 to 4.61; P<.001) and reported higher number of cardiovascular risk factors compared with noncarriers (2.4 [1.1] vs 2.0 [1.1]; P<.001). There were no significant differences in the adjusted odds associated with diabetes, dyslipidemia, smoking, or cardiovascular disease.

CONCLUSION

Despite having similar body weight and BMI, carriers of heterozygous variants in the leptin-melanocortin pathway had higher rates of hypertension than noncarriers. These findings point to an association between hypertension and leptin-melanocortin pathway variants.

Effects of oral non-protein calorie supplements on nutritional status among maintenance hemodialysis patients with protein-energy wasting: a multi-center randomized controlled trial

Protein-energy wasting (PEW) is prevalent in maintenance hemodialysis (MHD) patients, and is one of the major risk factors for poor outcomes and death. This study aimed to investigate the effects of non-protein calorie supplements on the nutritional status of MHD patients with PEW. MHD patients with PEW were enrolled in this multi-center, open-label, randomized controlled trial. Then, they were randomly assigned to the intervention group to receive the non-protein calorie supplements containing 280 kcal of energy every day for 6 months or the control group to complete all aspects of the study without receiving supplements. Patients in both groups received dietary counselling from dietitians. Data on nutritional assessments, anthropometric measurements, blood analysis and dietary recall were collected at the baseline and at six months from both groups. Statistical analyses were performed using analysis of covariance (ANCOVA) adjusted for sex and baseline values. Ninety-two MHD patients completed the study. A significant increase in the subjective global assessment (SGA) score was found in the intervention group compared with the control group (4.88 ± 1.41 vs. 4.40 ± 1.16, p = 0.044). The ratio of PEW patients (diagnosed with SGA ≤5) in the intervention group (61.2%) was also significantly lower than that in the control group (83.7%) (p < 0.001). Moreover, significant improvements in body mass index (20.81 ± 2.46 kg m^-2vs. 19.51 ± 2.60 kg m^-2, p < 0.001), nutrition risk screening 2002 (2.45 ± 1.40 vs. 3.12 ± 1.37, p = 0.038), mid-upper arm circumference (23.30 ± 2.78 cm vs. 21.75 ± 2.87 cm, p = 0.001), and mid-arm muscle circumference (20.51 ± 2.32 cm vs. 19.06 ± 2.92 cm, p = 0.005) were observed in the intervention group compared with the control group. Patients in the intervention group took in more dietary energy than the control group (26.96 ± 4.75 kcal per kg body weight per day vs. 24.33 ± 2.68 kcal per kg body weight per day, p < 0.001). In conclusion, non-protein calorie supplements may improve the nutritional status of MHD patients with PEW.

Screening of malnutrition with malnutrition inflammation score and geriatric nutritional risk index in hemodialysis patients

BACKGROUND AND AIMS

Screening malnutrition, which is the most common complication in hemodialysis patients, is extremely important for these patients. Malnutrition inflammation score (MIS) and geriatric nutritional risk index (GNRI) are malnutrition screening tests used in hemodialysis patients in recent years. The purposes of this study are to evaluate the nutritional status of hemodialysis patients with different screening tests and to determine the cutoff values for this disease-specific MIS and GNRI.

METHODS

The study was conducted with 194 adult patients including 98 males and 96 females whose mean age was 53.1 ± 10.96. Subjective global assessment (SGA) and MIS tests were applied, and the GNRI value was calculated for screening malnutrition. MIS and GNRI cutoff values were obtained by adopting the SGA scores as a standard and drawing a receiver operating characteristic curve. The tatistical Package for the Social Sciences-22.0 package program was used in the analysis.

RESULTS

According to SGA, 70.7% of the patients were nourished, 21.1% were mildly-moderately malnourished, and 8.2% were found to be severely malnourished. The optimal cutoff value predicted for malnutrition was 6.5 points (94.7% sensitivity and 98.5% specificity) for MIS and 86.0 points (64.9% sensitivity and 62.8% specificity) for GNRI. Based on these cutoff values, 28.9% of the patients were determined to be malnourished according to MIS and 45.4% according to GNRI.

CONCLUSION

In conclusion, screening tests are very important in the early identification of malnutrition in hemodialysis patients. This study was conducted to evaluate the malnutrition of hemodialysis patients with different screening tests. At the end of the study, the availability of MIS was found to be high in detecting malnutrition in hemodialysis patients because of its high accuracy and sensitivity of MIS. The cutoff points we identified for both MIS and GNRI are thought to facilitate the determination of malnutrition.

Profile of Obesity and Comorbidities and their Correlation among Hemodialysis Patients, Elbasan

INTRODUCTION: Nowadays, obesity is an enormous problem in the public health of undeveloped countries and developing countries. Being overweight, especially obesity in internal organs contributes to increased risk of metabolic and cardiovascular complications in patients with chronic kidney disease. There is no complete data available in our country on the correlation between obesity and comorbidity diseases among persons undergoing dialysis. So we do not know how BMI affects Diabetic or Cardio Vascular Disease (CVD) patients among dialysis patients. We, therefore, undertook this study to evaluate the association of obesity with mobility in hemodialysis patients at the Elbasan dialysis center. METHODOLOGY: This cross-sectional study was performed in 160 patients who have undergone the dialysis process at Elbasan Dialysis Center for three years (2016-2018). A standardized questionnaire was adopted to obtain data from all patients. The subjects were divided a priory into 4 categories based on the body mass index (BMI) (underweight <19, normal 19-25, pre-obese 25-30 and obese ≥30 kg/m2). Software SPSS version 20.0 is used to analyze and evaluate the data. Kaplan-Meier estimate were used to find the correlation between BMI with their prognostic abilities like cardiovascular disease and Diabetes Mellitus Type 2. We have considered statistically significant every p value less than 0.05. RESULT: Over all 160 patients, the men presented the highest number of cases compared to female 73.1% and 26.9% respectively. The mean age resulted 52.7 ± 15.6 years and age groups 50-59 years old and 60-69 years old with 29.4% and 34.3% respectively were the most frequent in this study. About the category of BMI index 8.8% patients resulted underweight, 45% were in normal weight, 28.2% were pre-obese and 6.6% were obese. We observed significant correlations between BMI and some of the demographic data such as: gender, age, place of residence, educational level, smoking and alcohol consumption for p <0.05. Changes in patient survival rates between BMI with DMT2 and cardiovascular disease are not statistically significant (long range p> 0.05). In terms of mortality, a strong significant correlation was observed with the age of 50-69 years and with the index of hemoglobin, urea and creatinine after dialysis with p value <0.05. CONCLUSION: In the paradoxical epidemiology, the overweight becomes chronic on hemodialysis patients and serves as a protective factor which is associated with better survival, but we weren`t found significant association between the BMI and some of the variables analyzed. This study presents a small number of chronic patients on hemodialysis center in Elbasan city. There is a need to better understand the reverse epidemiological causes in individuals on dialysis, which can help us improve the poor outcome in this population.

Survival bias may explain the appearance of the obesity paradox in hip fracture patients

Patients with low-energy hip fractures do not follow the obesity paradox as previously reported. In datasets where injury mechanism is not available, the use of age >50 years (as opposed to commonly used >65 years) as a surrogate for a low-energy hip fracture patients may be a more robust inclusion criterion.  PURPOSE: In elderly patients with a hip fracture, limited data suggests that obese patients counterintuitively have improved survival compared to normal-weight patients. This "obesity paradox" may be the byproduct of selection bias. We hypothesized that the obesity paradox would not apply to elderly hip fracture patients.

METHODS

The National Surgical Quality Improvement Project dataset identified 71,685 hip fracture patients ≥50 years-of-age with complete body mass index (BMI) data that underwent surgery. Patients were stratified into under and over 75-year-old cohorts (n=18,956 and 52,729, respectively). Within each age group, patients were stratified by BMI class and compared with respect to preoperative characteristics and 30-day mortality. Significant univariate characteristics (p<0.1) were included in multivariate analysis to determine the independent effect of obesity class on 30-day mortality (p<0.05).

RESULTS

Multivariate analysis of <75-year-old patients with class-III obesity were more likely to die within 30-days than similarly aged normal-weight patients (OR 1.91, CI 1.06-3.42, p=0.030). Multivariate analysis of ≥75-year-old overweight (OR 0.69, CI 0.62-0.77, p<0.001), class-I obese (OR 0.62, CI 0.51-0.74, p<0.001), or class-II obese (OR=0.69, CI 0.50-0.95, p=0.022) patients were less likely to die within 30-days when compared to similarly aged normal-weight patients.

CONCLUSIONS

Our data suggest that obesity is a risk factor for mortality in low-energy hip fracture patients, but the appearance of the "obesity paradox" in elderly hip fracture patients results from statistical bias that is only evident upon subgroup analysis.

Bariatric surgery prior to transplantation and risk of early hospital re-admission, graft failure, or death following kidney transplantation

Bariatric surgery has been shown to be safe in the dialysis population. Whether bariatric surgery before kidney transplantation influences posttransplant outcomes has not been examined nationally. We included severely obese (BMI >35) dialysis patients between 18 and 70 years who received a kidney transplant according to the US Renal Data System. We determined the association between history of bariatric surgery and risk of 30-day readmission, graft failure, or death after transplantation using multivariable logistic, Fine-Gray, and Cox models. We included 12 573 patients, of whom 503 (4%) received bariatric surgery before transplantation. Median age at transplant was 53 years; 42% were women. Overall, history of bariatric surgery was not statistically significantly associated with graft failure (HR 1.02; 95% CI 0.77-1.35) or death (HR 1.10; 95% CI 0.84-1.45). However, sleeve gastrectomy (vs. no bariatric surgery) was associated with lower risk of graft failure (HR 0.39; 95% CI 0.16-0.95). In conclusion, history of bariatric surgery prior to kidney transplantation was not associated with allograft or patient survival, but findings varied by surgery type. Sleeve gastrectomy was associated with better graft survival and should be considered in severely obese transplant candidates receiving dialysis.

KDOQI US Commentary on the 2020 KDIGO Clinical Practice Guideline on the Evaluation and Management of Candidates for Kidney Transplantation

Evaluation of patients for kidney transplant candidacy is a comprehensive process that involves a detailed assessment of medical and surgical issues, psychosocial factors, and patients' physical and cognitive abilities with an aim of balancing the benefits of transplantation and potential risks of surgery and long-term immunosuppression. There is considerable variability among transplant centers in their approach to evaluation and decision-making regarding transplant candidacy. The 2020 KDIGO (Kidney Disease: Improving Guidelines Outcome) clinical practice guideline on the evaluation and management of candidates for kidney transplantation provides practice recommendations that can serve as a useful reference guide to transplant professionals. The guideline, covering a broad range of topics, was developed by an international group of experts from transplant and nephrology through a review of literature published until May 2019. A work group of US transplant nephrologists convened by NKF-KDOQI (National Kidney Foundation-Kidney Disease Quality Initiative) chose key topics for this commentary with a goal of presenting a broad discussion to the US transplant community. Each section of this article has a summary of the key KDIGO guideline recommendations, followed by a brief commentary on the recommendations, their clinical utility, and potential implementation challenges. The KDOQI work group agrees broadly with the KDIGO recommendations but also recognizes and highlights the decision-making challenges that arise from lack of high-quality evidence and the need to balance equity with utility of organ transplantation.

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

Background

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

Methods

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

Results

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

Conclusions

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

Supplementary Information

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

Bariatric Surgery and Long-term Survival in Patients With Obesity and End-stage Kidney Disease

Importance

Obesity rates in patients with end-stage kidney disease are rising, contribute to excess morbidity, and limit access to kidney transplant. Despite this, there continues to be controversy around the use of bariatric surgery in this patient population.

Objective

To determine whether bariatric surgery is associated with improvement in long-term survival among patients with obesity and end-stage kidney disease.

Design, Setting, and Participants

Retrospective cohort study and secondary analysis of previously collected data from the United States Renal Data System registry (2006-2015). We used Cox proportional hazards analysis to evaluate differences in outcomes for patients receiving bariatric surgery (n = 1597) compared with a matched cohort of nonsurgical patients (n = 4750) receiving usual care. Data were analyzed between September 3, 2019, and November 13, 2019.

Exposure

Receipt of bariatric surgery.

Main Outcomes and Measures

All-cause mortality at 5 years. Secondary outcomes included disease-specific mortality and incidence of kidney transplant.

Results

Surgical and nonsurgical control patients had similar age, demographics, and comorbid disease burden. The mean (SD) age was 49.8 (11.2) years for surgical patients vs 51.7 (11.1) years for nonsurgical patients. Six hundred fifteen surgical patients (38.5%) were black vs 1833 nonsurgical patients (38.6%). Surgery was associated with lower all-cause mortality at 5 years compared with usual care (cumulative incidence, 25.6% vs 39.8%; hazard ratio, 0.69, 95% CI, 0.60-0.78). This was driven by lower mortality from cardiovascular causes at 5 years for patients undergoing bariatric surgery compared with nonsurgical control patients (cumulative incidence, 8.4% vs 17.2%; hazard ratio, 0.51; 95% CI, 0.41-0.65). Bariatric surgery was also associated with an increase in kidney transplant at 5 years (cumulative incidence, 33.0% vs 20.4%; hazard ratio, 1.82; 95% CI, 1.58-2.09). However, at 1 year, bariatric surgery was associated with higher all-cause mortality compared with usual care (cumulative incidence, 8.6% vs 7.7%; hazard ratio, 1.45; 95% CI, 1.13-1.85).

Conclusions and Relevance

Among patients with obesity and end-stage kidney disease, bariatric surgery was associated with lower all-cause mortality compared with usual care. Bariatric surgery was also associated with an increase in kidney transplant. Bariatric surgery may warrant further consideration in the treatment of patients with obesity and end-stage kidney disease.

Elevated serum uric acid and risk of cardiovascular or all-cause mortality in maintenance hemodialysis patients: A meta-analysis

BACKGROUND AND AIMS

Studies have shown inconsistent results about the association between serum uric acid (SUA) levels and mortality in hemodialysis patients. We performed this meta-analysis to determine whether higher SUA values comprised a risk factor of cardiovascular or all-cause mortality in maintenance hemodialysis patients.

METHODS AND RESULTS

Pubmed, Embase and the Cochrane library were searched up to August 31, 2020 for the longitudinal studies that investigated the association between the elevated SUA and cardiovascular or all-cause mortality risk in maintenance hemodialysis patients. Pooled adjusted hazard ratios (HR) and corresponding 95% confidence interval (CI) were calculated using a random-effects model. We included 10 studies with an overall sample of 264,571 patients with hemodialysis in this meta-analysis. Patients with the highest SUA were associated with a decreased risk of cardiovascular mortality (HR = 0.72, 95% CI 0.59-0.87) compared with patients with the lowest SUA after adjustment for potential confounders in a random effects model. Moreover, for each increase of 1 mg/dl of SUA, the overall risks of all-cause and cardiovascular mortality decreased by 6% and 9%, respectively (HR = 0.94, 95% CI 0.90-0.99; HR = 0.91, 95% CI 0.89-0.94).

CONCLUSION

Elevated SUA levels are strongly and independently associated with lower risk of cardiovascular mortality in maintenance hemodialysis patients. More designed studies, especially randomized controlled trials, should be conducted to determine whether high SUA levels is an independent risk factor of all-cause mortality in hemodialysis patients.

Changes in metabolic syndrome status affect the incidence of end-stage renal disease in the general population: a nationwide cohort study

Few studies have investigated the impact of a change in metabolic syndrome (MetS) components on clinical renal outcomes in the general population. Using nationally representative data from the Korean National Health Insurance System, 13,310,924 subjects who underwent two health examinations over 2 years and were free from end-stage renal disease (ESRD) from 2009 to 2012 were followed to the end of 2016. The subjects were divided into four groups according to the change in MetS components between the two visits over 2 years: no MetS (–/–), post-MetS (–/+), pre-MetS (+/–), and both MetS (+/+). After a median follow up of 5.11 years, 18,582 incident ESRD cases were identified. In the multivariate adjusted model, the hazard ratio (HR) and 95% confidence interval (CI) for the development of ESRD in the both-MetS (+/+) group compared with the no-MetS (–/–) group was 5.65 (95% CI, 5.42–5.89), which was independent of age, sex, and baseline estimated glomerular filtration rate. Additionally, the HR for the pre-MetS (+/–) group versus the no-MetS (–/–) group was 2.28 (2.15–2.42). In subgroup analysis according to renal function, the impact of a change in MetS on the incidence of ESRD was more pronounced in individuals with advanced renal dysfunction. Subjects with resolved MetS components had a decreased risk of ESRD, but not as low as those that never had MetS components. This provides evidence supporting the strategy of modulating MetS in the general population to prevent the development of ESRD.

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.

Body mass index and trajectories of cognitive decline among older Korean adults

Objectives: This study examined the relationship between body mass index (BMI) and trajectories of cognitive decline among older Korean adults.Methods: Participants were a nationally representative sample of 5126 Korean adults aged 60 or older from the Korean Longitudinal Study of Aging (KLoSA: 2006-2014). The main outcome variable, cognitive function, was measured with the Korean Mini-Mental State Examination (K-MMSE). According to the BMI values, respondents were divided into four groups at each wave: underweight (<18.5 kg/m²), healthy weight (18.5-22.9 kg/m²), overweight (23.0-24.9 kg/m²), and obese (≥25.0 kg/m²). Growth curve modeling was used to analyze the relationship of interest.Results: The growth curve modeling revealed that, regardless of BMI values, cognitive functioning declined as participants aged, and the rate of cognitive decline accelerated with age. After adjusting for all covariates, older Korean adults who were underweight displayed steeper declines in cognitive functioning, compared to those with a healthy weight. Conversely, overweight or obese older adults showed a much slower cognitive decline as they aged, after adjusting for covariates.Conclusion: Compared to people with a healthy BMI, people with a low BMI may be at risk for cognitive dysfunction, whereas a high BMI could function as a protective factor for cognitive dysfunction in older adulthood. Future research examining the mechanism for these trajectories are needed. Implications for research and clinical practice are discussed.

Sleeve Gastrectomy Compared with Gastric Bypass for Morbidly Obese Patients with End Stage Renal Disease: a Decision Analysis

INTRODUCTION

The use of bariatric surgery has increased for morbidly obese patients with end stage renal disease (ESRD) for whom listing on the waitlist is often restricted until a certain BMI threshold is achieved. Effective weight loss for this population improves access to life-saving renal transplantation. However, it is unclear whether sleeve gastrectomy (SG) vs Roux-en-Y gastric bypass (RYGB) is a more effective therapy for these patients.

METHODS

A decision analytic Markov state transition model was created to simulate the life of morbidly obese patients with ESRD who were deemed ineligible to be waitlisted for renal transplantation unless they achieved a BMI less than 35 kg/m². Life expectancy following weight management (MWM), RYGB, and SG were estimated. Base case patients were defined as having a pre-intervention BMI of 45 kg/m². Sensitivity analysis of initial BMI was performed. Markov parameters were extracted from literature review.

RESULTS

RYGB improved survival compared with SG and MWM. RYGB patients had higher rates of transplantation, leading to improved mean long-term survival. Base case patients who underwent RYGB gained 1.3 additional years of life compared with patient's who underwent SG and 2.6 additional years of life compared with MWM.

CONCLUSIONS

RYGB improves access to renal transplantation and thereby increases long-term survival compared with SG and MWM. The use of SG may be incongruent with the goal of improving access to renal transplantation for morbidly obese patients.

Body mass index and albumin levels are prognostic factors for long-term survival in elders with limited performance status

Elderly long-term care facility residents typically have musculoskeletal conditions that may lead to long-term disability and increased mortality. Our main objective was to explore the relationship between body mass index (BMI), albumin levels, and mortality in elderly individuals with limited performance status. Among 182 participants (mean age, 78.8 years; 57% women), 11%, 64%, and 25% had serum albumin levels of <2.8, 2.8-3.5, and >3.5 g/dL, respectively. After multivariate adjustments, diastolic blood pressure >90 mmHg was associated with all-cause mortality [hazard ratio (HR) = 2.08, 95% confidence interval (CI) = 1.13-3.82; P = 0.018]. In addition, BMI <18.5 kg/m2 and albumin level <2.8 g/dL associated with higher mortality than BMI = 18.5-24 kg/m2 and albumin level > 3.5 g/dL (HR = 1.80, 95% CI = 1.11-2.94 and HR = 2.54, 95% CI 1.22-5.30, respectively; P = 0.018 and 0.013, respectively). Highest mortality was noted in participants with albumin levels <2.8 g/dL and BMIs <18.5 kg/m2 (HR = 6.12, 95% CI = 1.85-20.21, P = 0.003). Combined hypoalbuminemia (albumin level < 2.8 g/dL) and low BMI (<18.5 kg/m2) may be a useful prognostic indicator of high mortality risk in elderly individuals with limited performance status.

Obesity in kidney transplantation

The prevalence of obesity among patients with chronic kidney disease continues to increase as a reflection of the trend observed in the general population. Factors affecting the access to the waiting list and the transplantability of this specific population will be analysed. From observational studies, kidney transplantation in obese patients carries an increased risk of surgical complications compared to the nonobese population; therefore, many centres have been reluctant to proceed with transplantation, despite this treatment modality confers a survival advantage over dialysis. As a consequence, obese patients continue to face decreased access to the waiting list, with a lower likelihood of being transplanted and higher waiting times when compared to the nonobese candidates. In this review will be described the current strategies for treatment of obesity in different settings (pretransplant, at transplant and post-transplant). Obesity represents a risk factor for surgical complications but not a contraindication for kidney transplantation; outcomes could be greatly improved with its multidisciplinary and multimodal treatment. The modern technology with minimally invasive techniques, mainly using robotic platform, allows a reduction in the surgical complications rate, with graft and patient survival rates comparable to the nonobese counterpart.

Association of Body Mass Index and Outcome in Acutely Ill Patients With Chronic Kidney Disease Requiring Intensive Care Therapy

OBJECTIVE

An association of body mass index (BMI) and outcome, the "obesity paradox," has been described in patients with chronic kidney disease (CKD) and end-stage renal disease. We sought to assess whether a potential beneficial effect of a high body mass is also seen in CKD patients with critical illness.

METHODS

In a retrospective analysis of a prospectively collected database of 123,416 patients from 107 Austrian intensive care units (ICUs) in whom BMI was available, the association of 6 groups of BMI and hospital mortality was assessed in 12,206 patients with CKD 3-5 by univariate and multivariate logistic regression analyses.

RESULTS

Patients with CKD were sicker, had a longer ICU stay, and had a higher ICU and hospital mortality than those without. The association of BMI and outcome in CKD patients indicated a U-shaped curve with the highest mortality in patients with BMI <20 and ≥40, and the lowest with a BMI between ≥25 and <40. This relationship was also significant in a multivariate analysis adjusted for severity of illness assessed by Simplified Acute Physiology Score III score, age, gender, admission diagnosis, and pre-existing comorbidities. It was not found in patients with CKD 5 on renal replacement therapy, in patients below 60 years of age, and those with diabetes mellitus requiring insulin treatment.

CONCLUSIONS

BMI is associated with better outcomes in CKD 3-5 patients who have acquired acute intermittent diseases and are admitted to an ICU, but not those requiring renal replacement therapy. This higher tolerance to acute disease processes may in part explain the "obesity paradox" observed in CKD patients.

Chronic Kidney Disease and the Adiposity Paradox: Valid or Confounded?

OBJECTIVE

Obesity, defined by body mass index (BMI), is associated with lower mortality risk in patients with chronic kidney disease (CKD). BMI and % body fat (%BF) are confounded by muscle mass, while DXA derived fat mass index (FMI) overcomes this limitation. We compared the associations between obesity and mortality in persons with CKD using multiple estimates of adiposity, and determined whether muscle mass, inflammation and weight loss modify these associations.

METHODS

Obesity was defined using BMI and DXA-derived FMI and %BF cut-offs in 2,852 NHANES participants with CKD from 1999-2006 and linked to the National Death Index with follow up through 2011. Cox proportional hazards models assessed associations between mortality and measures of obesity.

RESULTS

Obesity based on FMI and continuous variables, FMI, BMI and %BF were associated with lower mortality. The protective association of obesity was less pronounced among participants with higher muscle mass and was no longer significant after adjustment for prior weight loss. Inflammation did not modify these associations.

CONCLUSIONS

We observed lower mortality associated with higher fat mass, particularly among persons with lower muscle mass. The prevalence of >10% weight loss was half as common among obese compared to non-obese participants and confounded these associations.

Racial and Ethnic Disparities in the Obesity Paradox

Obesity is a major risk factor for cardiovascular disease and worse survival in the general population. However, in patients with end-stage renal disease (ESRD), higher body mass index and indexes of body fat and muscle are associated with better survival. Furthermore, these associations, which some have described as the obesity paradox, are more consistent in African American patients being treated with hemodialysis when compared with other racial-ethnic groups. This is in view of data indicating that although the rate of progression to ESRD is faster in African American patients, they have a survival advantage after transition to ESRD when compared with their white counterparts. These observations indicate that there may be significant interaction between race/ethnicity and association of body mass index with outcomes in patients with ESRD. In addition, it is possible that mechanisms underlying improved survival in African American hemodialysis patients are partly related to the association of body mass index with outcomes observed in this patient population. Some of these potential mechanisms may include comparatively reduced risk for protein-energy wasting and malnutrition, possible salutary effects of factors that play a role in energy preservation, resistance to deleterious effects of inflammation, and enhanced muscle mass and body composition. Given that ESRD is associated with significantly increased risk for morbidity and mortality, understanding the pathophysiologic mechanisms responsible for the obesity paradox across race-ethnic populations might help identify potential therapeutic targets that can be used to improve survival in this patient population.

Relationship Among Denture Status, Remaining Teeth Number, and Malnutrition in Patients With Chronic Kidney Disease

The purpose of the present study was to evaluate the relationship among the denture status, number of remaining teeth, and malnutrition in patients with chronic kidney disease (CKD). Seventy-three patients (43 men/30 women) who required hemodialysis were included in the study. Weight and height, Kt/V, urea reduction ratio, midweek interdialytic weight gain, ultrafiltration volume, and erythropoietin dosage were determined for all patients. Laboratory measurements and predialysis blood samples for biomarkers were collected within the monthly routine tests. Dental examination focused on the denture status and total number of remaining teeth. Denture status were classified into two groups as prosthesis group (patients have prosthesis) and no prosthesis group (patients do not have any kind of prosthesis). And also, patients were assigned to one of four categories based on the number of remaining natural teeth: (i) edentulous, (ii) 1-7 teeth, (iii) 8-19 teeth, and (iv) >20 teeth. The data were statistically analyzed (a = 0.05). Body mass index values were increased in the prosthesis patients. Serum albumin levels of the CKD patients were under the reference value (3.8 g/dL) both in prosthesis and no prosthesis groups. Patients who have eight and more teeth showed higher serum albumin levels, and patients who had 1-7 teeth showed lower serum albumin levels in prosthesis group. CKD patients' nutritional habits were affected by denture status (having prosthesis or not). The number of the remaining teeth in prosthesis group affected the serum albumin levels of CKD patients.

Malnutrition, inflammation, progression of vascular calcification and survival: Inter-relationships in hemodialysis patients

Background and aims

Malnutrition and inflammation are closely linked to vascular calcification (VC), the severity of which correlate with adverse outcome. However, there were few studies on the interplay between malnutrition, inflammation and VC progression, rather than VC presence per se. We aimed to determine the relationship of malnutrition, inflammation, abdominal aortic calcification (AAC) progression with survival in hemodialysis (HD) patients.

Methods

Malnutrition and inflammation were defined as low serum albumin (< 40 g/L) and high hs-CRP (≥ 28.57 nmol/L), respectively. We defined AAC progression as an increase in AAC score using lateral lumbar radiography at both baseline and one year later. Patients were followed up to investigate the impact of AAC progression on all-cause and cardiovascular mortality.

Results

AAC progressed in 54.6% of 97 patients (mean age 58.2±11.7 years, 41.2% men) at 1-year follow-up. Hypoalbuminemia (Odds ratio 3.296; 95% confidence interval 1.178–9.222), hs-CRP (1.561; 1.038–2.348), low LDL-cholesterol (0.976; 0.955–0.996), and the presence of baseline AAC (10.136; 3.173–32.386) were significant risk factors for AAC progression. During the mean follow-up period of 5.9 years, 38(39.2%) patients died and 27(71.0%) of them died of cardiovascular disease. Multivariate Cox regression analysis adjusted for old age, diabetes, cardiovascular history, and hypoalbuminemia determined that AAC progression was an independent predictor of all-cause mortality (2.294; 1.054–4.994).

Conclusions

Malnutrition and inflammation were significantly associated with AAC progression. AAC progression is more informative than AAC presence at a given time-point as a predictor of all-cause mortality in patients on maintenance HD.

Time-varying effects of body mass index on mortality among hemodialysis patients: Results from a nationwide Korean registry

Background

Unlike patterns observed in the general population, obesity is associated with better survival among hemodialysis patients, which could be explained by reverse causation or illness-related weight loss. However, the time-varying effect of body mass index (BMI) on hemodialysis survival has not been investigated. Therefore, this study investigated the time-varying effect of BMI on mortality after starting hemodialysis.

Methods

In the present study, we examined Korean Society of Nephrology data from 16,069 adult patients who started hemodialysis during or after the year 2000. Complete survival data were obtained from Statistics Korea. Survival analysis was performed using Cox regression and a non-proportional hazard fractional polynomial model.

Results

During the median follow-up of 8.6 years, 9,272 patients (57.7%) died. Compared to individuals with normal BMI (18.5–24.9 kg/m²), the underweight group (< 18.5 kg/m²) had a higer mortality hazard ratio (HR, 1.292; 95% confidence interval [CI], 1.203–1.387; P < 0.001) and the overweight group (25.0–29.9 kg/m²) had a lower mortality HR (0.904; 95% CI, 0.829–0.985; P = 0.022). The underweight group had increasing HRs during the first 3 to 7 years after starting hemodialysis, which varied according to age group. The young obese group (< 40 years old) had a U-shaped temporal trend in their mortality HRs, which reflected increased mortality after 7 years.

Conclusion

The obese hemodialysis group had better survival during the early post-dialysis period, although the beneficial effect of obesity disappeared 7 years after starting hemodialysis. The young obese group also had an increased mortality HR after 7 years.

Impact of body mass index on short-term and long-term survival in prevalent hemodialysis patients

INTRODUCTION

Numerous studies showed that higher body mass index (BMI) is associated with better survival in hemodialysis (HD) patients. Most of them evaluated short-term mortality. It has been suggested that presence of inflammation may be a key modifier of relationship between BMI and mortality in incident HD patients. We examined whether presence of inflammation modifies the association between BMI and mortality in both short-term and long-term follow-up in a large group of prevalent HD patients.

METHODS

A total of 3.252 HD patients from 41 HD centers were enrolled; the patients were divided into quartiles based on time-averaged BMI (Q1 < 21.5, Q2 21.5 to <24.3, Q3 24.3 to <27.4, Q4 ≥ 27.4 kg/m² ). Inflammation status was defined as present (inflamed) (C-reactive protein (CRP) ≥1.0 mg/dL and/or serum albumin ≤3.5 g/dL) or absent (noninflamed).

FINDINGS

During 7 years of follow-up 1386 patients (42.6%) died. Compared to noninflamed patients, inflamed patients in the lowest BMI quartile showed 5-fold increased risk for mortality in the short-term (95% confidence interval [CI] 2.82-9.22, P < 0.001) and 3-fold in the long-term (95%CI 2.42-4.27, P < 0.001) compared to the highest BMI quartile. Whereas, inflamed patients in the highest BMI quartile experienced 2-fold increased risk in short-term (95%CI 1.17-3.74, P = 0.01) and 1.68-fold increased risk in long-term (95%CI 1.30-2.18, P < 0.001) than in noninflamed patients. The protective effect of BMI for overall mortality was present in all age groups, in both genders, in patient with and without diabetes. BMI was not a mortality predictor in patients with HD duration more than 76 months at baseline. The protective effect of BMI was observed in all albumin tertiles. In patients in the lowest CRP tertile, BMI was not associated with mortality.

DISCUSSION

Higher BMI is associated with lower short-term and long-term mortality risk, especially in patients with inflammation in a prevalent HD population.

Observational Evidence for Unintentional Weight Loss in All-Cause Mortality and Major Cardiovascular Events: A Systematic Review and Meta-Analysis

The obesity paradox has been described in several observational cohorts and meta-analysis. However, evidence of the intentionality of weight loss in all-cause deaths and major cardiovascular events (MACE) in prospective cohorts is unclear. We analysed whether involuntary weight loss is associated with increased cardiovascular events and mortality. In a systematic review, we searched multiple electronic databases for observational studies published up to October 2016. Studies reporting risk estimates for unintentional weight loss compared with stable weight in MACE and mortality were included. Fifteen studies met the selection criteria, with a total of 178,644 participants. For unintentional weight loss, we found adjusted risk ratios (RRs) with confidence intervals (CIs) of 1.38 (95% CI: 1.23, 1.53) and 1.17 (95% CI: 0.98, 1.37) for all-cause mortality and MACE, respectively. Participants with comorbidities, overweight and obese populations, and older adults yielded RRs (95% CI) of 1.49 (1.30, 1.68), 1.11 (1.04, 1.18), and 1.81 (1.59, 2.03), respectively. Unintentional weight loss had a significant impact on all-cause mortality. We found no protective effect of being overweight or obese for unintentional weight loss and MACE.

Prescribing Hemodialysis or Hemodiafiltration: When One Size Does Not Fit All the Proposal of a Personalized Approach Based on Comorbidity and Nutritional Status

There is no simple way to prescribe hemodialysis. Changes in the dialysis population, improvements in dialysis techniques, and different attitudes towards the initiation of dialysis have influenced treatment goals and, consequently, dialysis prescription. However, in clinical practice prescription of dialysis still often follows a "one size fits all" rule, and there is no agreed distinction between treatment goals for the younger, lower-risk population, and for older, high comorbidity patients. In the younger dialysis population, efficiency is our main goal, as assessed by the demonstrated close relationship between depuration (tested by kinetic adequacy) and survival. In the ageing dialysis population, tolerance is probably a better objective: "good dialysis" should allow the patient to attain a stable metabolic balance with minimal dialysis-related morbidity. We would like therefore to open the discussion on a personalized approach to dialysis prescription, focused on efficiency in younger patients and on tolerance in older ones, based on life expectancy, comorbidity, residual kidney function, and nutritional status, with particular attention placed on elderly, high-comorbidity populations, such as the ones presently treated in most European centers. Prescription of dialysis includes reaching decisions on the following elements: dialysis modality (hemodialysis (HD) or hemodiafiltration (HDF)); type of membrane (permeability, surface); and the frequency and duration of sessions. Blood and dialysate flow, anticoagulation, and reinfusion (in HDF) are also briefly discussed. The approach described in this concept paper was developed considering the following items: nutritional markers and integrated scores (albumin, pre-albumin, cholesterol; body size, Body Mass Index (BMI), Malnutrition Inflammation Score (MIS), and Subjective Global Assessment (SGA)); life expectancy (age, comorbidity (Charlson Index), and dialysis vintage); kinetic goals (Kt/V, normalized protein catabolic rate (n-PCR), calcium phosphate, parathyroid hormone (PTH), beta-2 microglobulin); technical aspects including vascular access (fistula versus catheter, degree of functionality); residual kidney function and weight gain; and dialysis tolerance (intradialytic hypotension, post-dialysis fatigue, and subjective evaluation of the effect of dialysis on quality of life). In the era of personalized medicine, we hope the approach described in this concept paper, which requires validation but has the merit of providing innovation, may be a first step towards raising attention on this issue and will be of help in guiding dialysis choices that exploit the extraordinary potential of the present dialysis "menu".

Lower body mass index and mortality in older adults starting dialysis

Lower body mass index (BMI) has consistently been associated with mortality in elderly in the general and chronic disease populations. Remarkably, in older incident dialysis patients no association of BMI with mortality was found. We performed an in-depth analysis and explored possible time-stratified effects of BMI. 908 incident dialysis patients aged ≥65 years of the NECOSAD study were included, and divided into tertiles by baseline BMI (<23.1 (lower), 23.1–26.0 (reference), ≥26.0 (higher) kg/m²). Because the hazards changed significantly during follow-up, the effect of BMI was modeled for the short-term (<1 year) and longer-term (≥1 year after dialysis initiation). During follow-up (median 3.8 years) 567 deaths occurred. Lower BMI was associated with higher short-term mortality risk (adjusted-HR 1.63 [1.14–2.32] P = 0.007), and lower longer-term mortality risk (adjusted-HR 0.81 [0.63–1.04] P = 0.1). Patients with lower BMI who died during the first year had significantly more comorbidity, and worse self-reported physical functioning compared with those who survived the first year. Thus, lower BMI is associated with increased 1-year mortality, but conditional on surviving the first year, lower BMI yielded a similar or lower mortality risk compared with the reference. Those patients with lower BMI, who had limited comorbidity and better physical functioning, had better survival.

The Incidence and Pathophysiology of the Obesity Paradox: Should Peritoneal Dialysis and Kidney Transplant Be Offered to Patients with Obesity and End-Stage Renal Disease?

PURPOSE OF REVIEW

To educate nephrologists and primary-care physicians about the incidence, pathophysiology, and survival benefits of the obesity paradox in end-stage renal disease (ESRD). This review also discusses the future of kidney transplant and peritoneal dialysis in obese dialysis patients.

RECENT FINDINGS

Obesity paradox in ESRD was first reported three decades ago, and since then, there have been several epidemiological studies that confirmed the phenomenon. Regardless of the anthropometric indices used to define obesity in ESRD patients, these markers serve to predict the dialysis patient's survival. The pathophysiology of obesity paradox tends to be multifactorial. Recent cohort studies demonstrated a survival benefit in all race and ethnic groups, but Hispanics and blacks experienced increased survival rates when compared to non-Hispanic whites. Obese dialysis patients should be offered peritoneal dialysis, especially if they are new to dialysis and have an adequate renal residual function. Several studies have shown that the benefit of receiving kidney transplant in obese patients exceeds the risks. The robotic-assisted kidney transplant (RAKT) procedure is the latest innovation that could offer hope for obese dialysis patients who have been denied or are waiting for kidney transplant. The obesity paradox phenomenon in ESRD is a unique illustration of survival benefit in a population that has a high overall annual mortality. Peritoneal dialysis should be encouraged for obese patients who have preserved residual renal function. Kidney transplant centers should encourage RAKT utilization in obese dialysis patients instead of denying them a kidney transplant.

Obesity Paradox in Advanced Kidney Disease: From Bedside to the Bench

While obesity is associated with a variety of complications including diabetes, hypertension, cardiovascular disease and premature death, observational studies have also found that obesity and increasing body mass index (BMI) can be linked with improved survival in certain patient populations, including those with conditions marked by protein-energy wasting and dysmetabolism that ultimately lead to cachexia. The latter observations have been reported in various clinical settings including end-stage renal disease (ESRD) and have been described as the "obesity paradox" or "reverse epidemiology", engendering controversy. While some have attributed the obesity paradox to residual confounding in an effort to "debunk" these observations, recent experimental discoveries provide biologically plausible mechanisms in which higher BMI can be linked to longevity in certain groups of patients. In addition, sophisticated epidemiologic methods that extensively adjusted for confounding have found that the obesity paradox remains robust in ESRD. Furthermore, novel hypotheses suggest that weight loss and cachexia can be linked to adverse outcomes including cardiomyopathy, arrhythmias, sudden death and poor outcomes. Therefore, the survival benefit observed in obese ESRD patients can at least partly be derived from mechanisms that protect against inefficient energy utilization, cachexia and protein-energy wasting. Given that in ESRD patients, treatment of traditional risk factors has failed to alter outcomes, detailed translational studies of the obesity paradox may help identify innovative pathways that can be targeted to improve survival. We have reviewed recent clinical evidence detailing the association of BMI with outcomes in patients with chronic kidney disease, including ESRD, and discuss potential mechanisms underlying the obesity paradox with potential for clinical applicability.

Impact of Obesity on Modality Longevity, Residual Kidney Function, Peritonitis, and Survival Among Incident Peritoneal Dialysis Patients

BACKGROUND

The prevalence of severe obesity, often considered a contraindication to peritoneal dialysis (PD), has increased over time. However, mortality has decreased more rapidly in the PD population than the hemodialysis (HD) population in the United States. The association between obesity and clinical outcomes among patients with end-stage kidney disease remains unclear in the current era.

STUDY DESIGN

Historical cohort study.

SETTING & PARTICIPANTS

15,573 incident PD patients from a large US dialysis organization (2007-2011).

PREDICTOR

Body mass index (BMI).

OUTCOMES

Modality longevity, residual renal creatinine clearance, peritonitis, and survival.

RESULTS

Higher BMI was significantly associated with shorter time to transfer to HD therapy (P for trend < 0.001), longer time to kidney transplantation (P for trend < 0.001), and, with borderline significance, more frequent peritonitis-related hospitalization (P for trend = 0.05). Compared with lean patients, obese patients had faster declines in residual kidney function (P for trend < 0.001) and consistently achieved lower total Kt/V over time (P for trend < 0.001) despite greater increases in dialysis Kt/V (P for trend < 0.001). There was a U-shaped association between BMI and mortality, with the greatest survival associated with the BMI range of 30 to < 35kg/m2 in the case-mix adjusted model. Compared with matched HD patients, PD patients had lower mortality in the BMI categories of < 25 and 25 to < 35kg/m2 and had equivalent survival in the BMI category ≥ 35kg/m2 (P for interaction = 0.001 [vs < 25 kg/m2]). This attenuation in survival difference among patients with severe obesity was observed only in patients with diabetes, but not those without diabetes.

LIMITATIONS

Inability to evaluate causal associations. Potential indication bias.

CONCLUSIONS

Whereas obese PD patients had higher risk for complications than nonobese PD patients, their survival was no worse than matched HD patients.

Risk of hospitalization associated with body mass index and weight changes among prevalent haemodialysis patients

The impact of body mass index (BMI) and body weight on hospitalization rates in haemodialysis patients is unknown. This study hypothesizes that being either underweight or obese is associated with a higher hospitalization rate. Observational study of 6296 European haemodialysis patients with prospective data collection and follow-up every six months for three years (COSMOS study). The risk of being hospitalized was estimated by a time-dependent Cox regression model and the annual risk (incidence rate ratios, IRR) by Poisson regression. We considered weight loss, weight gain and stable weight. Weight change analyses were also performed after patient stratification according to their baseline BMI. A total of 3096 patients were hospitalized at least once with 9731 hospitalizations in total. The hospitalization incidence (fully adjusted IRR 1.28, 95% CI [1.18-1.39]) was higher among underweight patients (BMI <20kg/m²) than patients of normal weight (BMI 20-25kg/m²), while the incidence of overweight (0.88 [0.83-0.93]) and obese patients (≥30kg/m², 0.85 [0.79-0.92]) was lower. Weight gain was associated with a reduced risk of hospitalization. Conversely, weight loss was associated with a higher hospitalization rate, particularly in underweight patients (IRR 2.85 [2.33-3.47]). Underweight haemodialysis patients were at increased risk of hospitalization, while overweight and obese patients were less likely to be hospitalized. Short-term weight loss in underweight individuals was associated with a strikingly high hospitalization rate.

The Relationship between Body Mass Index and Organism-Specific Peritonitis

Background

Obesity is increasingly prevalent worldwide, and a greater number of patients initiate renal replacement therapy with a high body mass index (BMI). This study aimed to evaluate the association between BMI and organism-specific peritonitis.

Methods

All adult patients who initiated peritoneal dialysis (PD) in Australia between January 2004 and December 2013 were included. Data were accessed through the Australia and New Zealand Dialysis and Transplant (ANZDATA) Registry. The co-primary outcomes of this study were time to first organism-specific peritonitis episode, specifically gram-positive, gram-negative, culture-negative, and fungal. Secondary outcomes were individual rates of organism-specific peritonitis for the same 4 microbiological categories.

Results

There were 7,381 peritonitis episodes among the 8,343 incident PD patients evaluated. After multivariable adjustment, obese patients (BMI 30 – 34.9 kg/m2) had an increased risk of fungal peritonitis (adjusted hazard ratio [HR] 1.69, 95% confidence interval [CI] 1.18 – 2.42), very obese patients (BMI ≥ 35 kg/m2) had a significantly higher risk of gram-positive peritonitis (HR 1.15, 95% CI 1.02 – 1.30), while both obese and very obese patients experienced significantly higher risks of gram-negative peritonitis (HR 1.29, 95% CI 1.11 – 1.50 and HR 1.30, 95% CI 1.08 – 1.57, respectively) compared with patients with normal BMI (20 – 24.9 kg/m2). Obesity and severe obesity were independently associated with increased incidence rate ratios of all forms of organism-specific peritonitis with a non-significant trend for severe obesity and gram-negative peritonitis association.

Conclusion

Among Australian patients, obesity and severe obesity are associated with significantly increased rates of gram-positive, gram-negative, fungal, and culture-negative peritonitis.

Longitudinal Weight Change During CKD Progression and Its Association With Subsequent Mortality

BACKGROUND

Few studies have investigated the changes in weight that may occur over time among adults with the progression of chronic kidney disease (CKD). Whether such weight changes are independently associated with death after the onset of end-stage renal disease has also not been rigorously examined.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

We studied 3,933 participants of the Chronic Renal Insufficiency Cohort (CRIC) Study, a longitudinal cohort of patients with CKD. We also performed similar analyses among 1,067 participants of the African American Study of Kidney Disease and Hypertension (AASK).

PREDICTORS

Estimated glomerular filtration rate (eGFR) and weight change during CKD.

OUTCOME

Weight and all-cause mortality after dialysis therapy initiation.

RESULTS

During a median follow-up of 5.7 years in CRIC, weight change was not linear. Weight was stable until cystatin C-based eGFR (eGFRcys) decreased to <35mL/min/1.73m2; thereafter, weight declined at a mean rate of 1.45 kg (95% CI, 1.19-1.70) for every 10 mL/min/1.73m2 decline in eGFRcys. Among the 770 CRIC participants who began hemodialysis or peritoneal dialysis therapy during follow-up, a >5% annualized weight loss after eGFR decreased to <35mL/min/1.73m2 was associated with a 54% higher risk for death after dialysis therapy initiation (95% CI, 1.17-2.03) compared with those with more stable weight (annualized weight changes within 5% of baseline) in adjusted analysis. Similar findings were observed in the AASK.

LIMITATIONS

Inclusion of research participants only; inability to distinguish intentional versus unintentional weight loss.

CONCLUSIONS

Significant weight loss began relatively early during the course of CKD and was associated with a substantially higher risk for death after dialysis therapy initiation. Further studies are needed to determine whether interventions to optimize weight and nutritional status before the initiation of dialysis therapy will improve outcomes after end-stage renal disease.

Body Mass Index Change and Hospitalization Risk in Elderly Hemodialysis Patients: Results from Japanese Dialysis Outcomes and Practice Patterns Study

BACKGROUND

Short-term weight gains and losses are associated with a lower and higher mortality risk, respectively, in patients undergoing hemodialysis (HD). However, little is known about their association with the risk of subsequent hospitalization.

METHODS

In a prospective cohort of 1,804 HD patients aged ≥65 years enrolled in the Japanese Dialysis Outcomes and Practice Patterns Study phases 3 (2005-2008) and 4 (2009-2011), we examined the associations between changes in body mass index (BMI) over a 4-month baseline period (<-3%, -3 to <-1%, -1 to <1% [reference], 1 to <3%, and ≥3%) and subsequent risk of all-cause, cardiovascular, and noncardiovascular hospitalization using Cox models with adjustment for potential confounders.

RESULTS

During a median follow-up of 1.2 years, we noted 1,028 incident hospitalizations for any cause, including 275 and 753 hospitalizations for cardiovascular and noncardiovascular causes, respectively. An L-shaped association was observed between BMI change and all-cause hospitalization. The multivariable-adjusted hazard ratios (HRs; 95% CI) of all-cause hospitalization associated with BMI changes of <-3%, -3 to <-1%, 1 to <3%, and ≥3% (vs. -1 to <1%) were 1.29 (1.01-1.65), 1.22 (0.98-1.51), 1.04 (0.83-1.29), and 1.10 (0.83-1.45), respectively. Qualitatively similar associations were present for cardiovascular-related hospitalization (corresponding HRs [95% CI]: 1.58 [1.06-2.37], 1.09 [0.75-1.58], 0.99 [0.72-1.36], and 0.91 [0.51-1.64], respectively) but not for noncardiovascular-related hospitalization (corresponding HRs [95% CI]: 1.19 [0.90-1.57], 1.26 [0.99-1.59], 1.06 [0.84-1.35], and 1.18 [0.86-1.63], respectively).

CONCLUSIONS

Decreases in BMI over a relatively short-term period were independently associated with higher risk of subsequent hospitalization, particularly cardiovascular-related hospitalization, among elderly HD patients.

Long-Term Survivor Characteristics in Hemodialysis Patients with Type 2 Diabetes

BACKGROUND

Data concerning long-term mortality predictors among large, purely diabetic hemodialysis collectives are scarce.

METHODS

We used data from a multicenter, prospective, randomized trial among 1,255 hemodialysis patients with type 2 diabetes mellitus (T2DM) and its observational follow-up study. The association of 10 baseline candidate variables with mortality was assessed by Cox proportional hazards regression.

RESULTS

Overall, 103 participants survived the median follow-up of 11.5 years. Significant predictors of mortality were age (hazard ratio [HR] 1.03, 95% CI 1.02-1.04), cardiovascular (HR 1.42, 95% CI 1.25-1.62) and peripheral vascular disease (HR 1.55, 95% CI 1.36-1.76), higher hemoglobin A1c (HbA1c; HR 1.08, 95% CI 1.03-1.14), and loss of self-dependency (HR 1.20, 95% CI 1.03-1.39). Higher albumin (HR 0.72, 95% CI 0.59-0.89) and body mass index (BMI; HR 0.98, 95% CI 0.96-0.99) had protective associations. There was no significant association with sex, diabetes duration, and cerebrovascular diseases. Subgroup analyses by age and diabetes duration showed stronger associations of cardiovascular disease, HbA1c, albumin, BMI, and loss of self-dependency in younger patients and/or shorter diabetes duration. Loss of self-dependency and energy resources (albumin, BMI) increased mortality more severely in women, whilst the impact of cardiovascular and peripheral vascular diseases was more pronounced in men.

CONCLUSION

Long-term mortality risk in patients with T2DM on hemodialysis was associated with higher age, vascular diseases, HbA1c, loss of self-dependency, and low energy resources. Interestingly, it does not vary between sexes. Further individualized prognosis estimation and therapy should strongly depend on age, diabetes duration, and gender.

Modeling longitudinal data and its impact on survival in observational nephrology studies: tools and considerations

Nephrologists and kidney disease researchers are often interested in monitoring how patients' clinical and laboratory measures change over time, what factors may impact these changes, and how these changes may lead to differences in morbidity, mortality, and other outcomes. When longitudinal data with repeated measures over time in the same patients are available, there are a number of analytical approaches that could be employed to describe the trends and changes in these measures, and to explore the associations of these changes with outcomes. Researchers may choose a streamlined and simplified analytic approach to examine trajectories with subsequent outcomes such as estimating deltas (subtraction of the last observation from the first observation) or estimating per patient slopes with linear regression. Conversely, they could more fully address the data complexity by using a longitudinal mixed model to estimate change as a predictor or employ a joint model, which can simultaneously model the longitudinal effect and its impact on an outcome such as survival. In this review, we aim to assist nephrologists and clinical researchers by reviewing these approaches in modeling the association of longitudinal change in a marker with outcomes, while appropriately considering the data complexity. Namely, we will discuss the use of simplified approaches for creating predictor variables representing change in measurements including deltas and patient slopes, as well more sophisticated longitudinal models including joint models, which can be used in addition to simplified models based on the indications and objectives of the study as warranted.

Obesity and the risk of cardiovascular and all-cause mortality in chronic kidney disease: a systematic review and meta-analysis

Background

Obesity is a risk factor for cardiovascular disease and death in people without chronic kidney disease (CKD), but the effect of obesity in people with CKD is uncertain.

Methods

Medline and Embase (from inception to January 2015) were searched for cohort studies measuring obesity by body mass index (BMI), waist:hip ratio (WHR) and/or waist circumference (WC) and all-cause and cardiovascular mortality or events in patients with any stage of CKD. Data were summarized using random effects models. Meta-regression was conducted to assess sources of heterogeneity.

Results

Of 4065 potentially eligible citations, 165 studies ( n = 1 534 845 participants) were analyzed. In studies that found a nonlinear relationship, underweight people with CKD (3-5) on hemodialysis experienced an increased risk of death compared with those with normal weight. In transplant recipients, excess risk was observed at levels of morbid obesity (>35 kg/m 2 ). Of studies that found the relationship to be linear, a 1 kg/m 2 increase in BMI was associated with a 3 and 4% reduction in all-cause and cardiovascular mortality in patients on hemodialysis, respectively {adjusted hazard ratio [HR] 0.97 [95% confidence interval (CI) 0.96-0.98] and adjusted HR 0.96 (95% CI 0.92-1.00)}. In CKD Stages 3-5, for every 1 kg/m 2 increase in BMI there was a 1% reduction in all-cause mortality [HR 0.99 (95% CI 0.0.97-1.00)]. There was no apparent association between obesity and mortality in transplanted patients or those on peritoneal dialysis. Sparse data for WHR and WC did not allow further analyses.

Conclusions

Being obese may be protective for all-cause mortality in the predialysis and hemodialysis populations, while being underweight suggests increased risk, but not in transplant recipients.

Higher Adiposity Is Associated With Slower Cognitive Decline in Hypertensive Patients: Secondary Analysis of the China Stroke Primary Prevention Trial

BACKGROUND

Obesity is a risk factor for many diseases. However, the potential association between adiposity and cognitive decline in hypertensive patients is inconclusive. We performed a secondary data analysis of the CSPPT (China Stroke Primary Prevention Trial) to examine whether adiposity is correlated with longitudinal cognitive performance in hypertensive adults.

METHODS AND RESULTS

The analysis included 16 791 patients in the CSPPT who received at least 2 cognitive assessments by the Mini-Mental State Examination (MMSE) during the follow-up (median, 4.5 years; interquartile range, 4.2-4.8 years). Outcomes included changes in MMSE scores and cognitive impairment (defined as MMSE score less than education-specific cutoff point). A marked reduction in MMSE scores at the final (compared with at the 1-year) follow-up was apparent in both men (n=4838; mean [SD] score, 0.41 [3.62]) and women (n=7190; mean [SD] score, 1.07 [4.61]; both P<0.001). Analysis using a mixed-effects model revealed an association between higher body mass index with less MMSE decline, even after controlling for demographics and comorbidities (men, β=0.0134 [SE, 0.0036]; women, β=0.0133 [SE, 0.0034]; both P<0.001). A total of 1037 men (15.3%) and 3317 women (33.1%) developed cognitive impairment. In multivariable Cox regression analyses, being obese in men (11.3% versus 18.0%; hazard ratio, 0.75; 95% confidence interval, 0.60-0.94) and women (30.1% versus 36.5%; hazard ratio, 0.82; 95% confidence interval, 0.74-0.91) was a protective factor against cognitive impairment compared with normal body mass index.

CONCLUSIONS

Higher adiposity is independently associated with slower cognitive decline in Chinese hypertensive adults.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00794885 CSPPT.

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.