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

The safety of a low-protein diet in older adults with advanced chronic kidney disease

BACKGROUND

A low-protein diet (LPD) is recommended to patients with advanced chronic kidney disease (CKD), whereas geriatric guidelines recommend a higher amount of protein. The aim of this study was to evaluate the safety of LPD treatment in older adults with advanced CKD.

METHODS

The EQUAL study is a prospective, observational study including patients ≥65 years of age with an incident estimated glomerular filtration rate <20 ml/min/1.73 m2 in six European countries with follow-up through 6 years. Nutritional status was assessed by a 7-point subjective global assessment (SGA) every 3-6 months. Prescribed diet (g protein/kg of bodyweight) was recorded on every study visit; measured protein intake was available in three countries. Time to death and decline in nutritional status (SGA decrease of ≥2 points) were analysed using marginal structural models with dynamic inverse probability of treatment and censoring weights.

RESULTS

Of 1738 adults (631 prescribed LPD at any point during follow-up), there were 1319 with repeated SGA measurements, of which 267 (20%) decreased in SGA ≥2 points and 565 (32.5%) who died. There was no difference in survival or decrease in nutritional status for patients prescribed a LPD ≤0.8 g/kg ideal bodyweight {odds ratio [OR] for mortality 1.15 [95% confidence interval (CI) 0.86-1.55)] and OR for decrease in SGA 1.11 [95% CI 0.74-1.66]} in the adjusted models. In patients prescribed a LPD <0.6 g/kg ideal bodyweight, the results were similar. There was a significant interaction with LPD and older age >75 years, lower SGA and higher comorbidity burden for both mortality and nutritional status decline.

CONCLUSIONS

In older adults with CKD approaching end-stage kidney disease, a traditional LPD prescribed and monitored according to routine clinical practice in Europe appears to be safe.

Kidney Transplant Candidacy: Addressing Common Medical and Psychosocial Barriers to Transplant

Improving access to kidney transplants remains a priority for the transplant community. However, many medical, psychosocial, geographic, and socioeconomic barriers exist that prevent or delay transplantation for candidates with certain conditions. There is a lack of consensus regarding how to best approach many of these issues and barriers, leading to heterogeneity in transplant centers' management and acceptance practices for a variety of pretransplant candidate issues. In this review, we address several of the more common contemporary patient medical and psychosocial barriers frequently encountered by transplant programs. The barriers discussed here include kidney transplant candidates with obesity, older age, prior malignancy, cardiovascular disease, history of nonadherence, and cannabis use. Improving understanding of how to best address these specific issues can empower referring providers, transplant programs, and patients to address these issues as necessary to progress toward eventual successful transplantation.

Risk Factors for Potential Drug-Drug Interactions in Patients on Chronic Peritoneal Dialysis

INTRODUCTION

The prevalence of potential drug-drug interactions (pDDIs) is becoming a major safety concern, as it has been previously linked to a significant number of adverse drug events and could have serious consequences for patients, including death. This is especially relevant for patients with chronic renal failure, as they are particularly vulnerable to drug-drug interactions. The aim of this study was to evaluate the prevalence and associated factors of pDDIs in patients receiving chronic peritoneal dialysis.

METHODS

An observational, cross-sectional study was conducted on consecutive peritoneal dialysis patients attending four tertiary care hospitals for regular monthly examination. The primary outcome was the number of pDDIs identified using Lexicomp. Potential predictors were determined using multiple linear regression.

RESULTS

Total number of patients included in the study was 140. The results showed that pDDIs were highly prevalent, especially in patients who use antiarrhythmics (p = 0.001), have diabetes mellitus (p = 0.001), recently started peritoneal dialysis (p = 0.003), or have higher number of prescribed drugs (p < 0.001). Number of prescribed drugs (p < 0.001) remained a significant predictor of high-risk pDDIs in addition to the female gender (p = 0.043).

CONCLUSION

Clinicians should be particularly cautious when prescribing multiple medications to high-risk patients, such as peritoneal dialysis patients, to mitigate the risk of drug-drug interactions and associated adverse health outcomes.

Body Mass Index and Clinical and Health Status Outcomes in Chronic Coronary Disease and Advanced Kidney Disease in the ISCHEMIA-CKD Trial

OBJECTIVE

This study aimed to assess whether an obesity paradox (lower event rates with higher body mass index [BMI]) exists in participants with advanced chronic kidney disease (CKD) and chronic coronary disease in the International Study of Comparative Health Effectiveness of Medical and Invasive Approaches (ISCHEMIA)-CKD, and whether BMI modified the effect of initial treatment strategy.

METHODS

Baseline BMI was analyzed as both a continuous and categorical variable (< 25, ≥ 25 to < 30, ≥ 30 kg/m2). Associations between BMI and the primary outcome of all-cause death or myocardial infarction (D/MI), and all-cause death, cardiovascular death, and MI individually were estimated. Associations with health status were also evaluated using the Seattle Angina Questionnaire-7, the Rose Dyspnea Scale, and the EuroQol-5D Visual Analog Scale.

RESULTS

Body mass index ≥ 30 kg/m2 vs < 25 kg/m2 demonstrated increased risk for MI (hazard ratio [HR] [95% confidence interval] = 1.81 [1.12-2.92]) and for D/MI (HR 1.45 [1.06-1.96]) with a HR for MI of 1.22 (1.05-1.40) per 5 kg/m2 increase in BMI in unadjusted analysis. In multivariate analyses, a BMI ≥ 30 kg/m2 was marginally associated with D/MI (HR 1.43 [1.00-2.04]) and greater dyspnea throughout follow-up (P < .05 at all time points). Heterogeneity of treatment effect between baseline BMI was not evident for any outcome.

CONCLUSIONS

In the ISCHEMIA-CKD trial, an obesity paradox was not detected. Higher BMI was associated with worse dyspnea, and a trend toward increased D/MI and MI risk. Larger studies to validate these findings are warranted.

Kidney Function and Physical Performance Decline: The Brain in Kidney Disease (BRINK) Cohort Study

Rationale & Objective

Patients with kidney failure have poor physical performance, but its trajectory is less clear. We examined physical function over the course of kidney disease, including the transition to dialysis.

Study Design

Observational cohort.

Setting & Participants

Community-dwelling adults aged ≥45 years in the Brain in Kidney Disease (BRINK) cohort study.

Predictors

Estimated glomerular filtration rate (eGFR) and urine albumin to creatinine ratio (UACR).

Outcomes

Change in physical performance using the Short Physical Performance Battery (SPPB) (primary) and gait speed (secondary).

Analytical Approach

Linear mixed effects regression models.

Results

The analytical cohort included 562 participants with mean age of 69.3 (SD, 9.8) years followed for up to 63 months. In total, 49.8% were women. In addition, 79.9% self-identified as White, and 15.3% self-identified as Black. In total, 48.8% had diabetes. Mean eGFR at baseline was 48.1 (SD, 24.3) mL/min/1.73 m2. In unadjusted analysis, lower eGFR was associated with greater decline in SPPB score (P trend < 0.001). The decline in SPPB score was larger among participants with lower eGFR, with a gradient from -0.15 (95% CI, -0.23 to -0.07) points per year for participants with eGFR ≥60 mL/min/1.73 m2 to -0.56 (95% CI, -0.84 to -0.27) for participants with eGFR <15 mL/min/1.73 m2 and -0.61 (95% CI, -0.90 to -0.33) after dialysis initiation. In covariate-adjusted models, SPPB did not continue to decline after dialysis initiation. In secondary analyses evaluating change in gait speed, gait speed continued to decline after dialysis initiation. Higher UACR was also associated with a greater decline in SPPB score and gait speed in unadjusted and adjusted models.

Limitations

Small number of participants started dialysis.

Conclusions

We found a graded association of chronic kidney disease stage and albuminuria with decline in physical performance. The decline in SPPB was not accelerated after dialysis initiation in covariate-adjusted models, whereas gait speed continued to decline.

Weight change in chronic kidney disease: Association with mortality and kidney function

Background

Excess body weight is a risk factor for the progression of chronic kidney disease (CKD), but weight loss in CKD has been associated with higher mortality. Consequently, blanket weight loss recommendations in this population are controversial. Little data is available on the patterns of weight-change in CKD. The authors aimed to describe weight-changes in moderate/severe CKD and explore associations with mortality and renal endpoints in patients with overweight and obesity.

Methods

Non-dialysis Canberra Hospital patients with estimated glomerular filtration (eGFR) < 60 mL/min/1.73 m2 and body mass index (BMI) ≥25 kg/m2 were followed for up to 5.5 years. Weight-change ≥5% was considered clinically significant. The renal endpoint was defined as the commencement of dialysis or transplant or a ≥40% fall in eGFR. Relationships between weight-change in the first year of follow-up and mortality or the renal endpoint were assessed using Cox-regression.

Results

Three hundred ten patients (median age 75, median BMI 31 kg/m2) were identified. 68% had Stage-4 CKD at baseline. Over 4.4-years median follow-up, 128 died and 140 had significant weight-change. During the first year of follow-up, 42 patients lost and 23 gained ≥5% body weight, of whom only 3 had intentionally lost weight. On multivariate regression, significant weight loss/gain at 1-year was associated with 2.74 (p < 0.0005) and 2.67 (p = 0.003) hazard of subsequent death and with 2.51 (p = 0.004) and 2.20 (p = 0.05) hazard of the renal endpoint respectively. There was no association between baseline eGFR and subsequent weight change.

Conclusions

Patients with moderate/severe CKD experience significant weight-change, but this has no relationship to baseline kidney function. Significant weight-change is associated with higher subsequent mortality and loss of kidney function, but this association is likely significantly affected by confounding.

Lipid parameters, adipose tissue distribution and prognosis prediction in chronic kidney Disease patients

BACKGROUND

Lipid management in clinic is critical to the prevention and treatment of Chronic kidney disease (CKD), while the manifestations of lipid indicators vary in types and have flexible association with CKD prognosis.

PURPOSE

Explore the associations between the widely used indicators of lipid metabolism and their distribution in clinic and CKD prognosis; provide a reference for lipid management and inform treatment decisions for patients with non-dialysis CKD stage 3-5.

METHODS

This is a retrospective cohort study utilizing the Self-Management Program for Patients with Chronic Kidney Disease Cohort (SMP-CKD) database of 794 individuals with CKD stages 3-5. It covers demographic data, clinical diagnosis and medical history collection, laboratory results, circulating lipid profiles and lipid distribution assessments. Primary endpoint was defined as a composite outcome(the initiation of chronic dialysis or renal transplantation, sustained decline of 40% or more in estimated glomerular filtration rate (eGFR), doubled of serum creatinine (SCr) from the baseline, eGFR less than 5 mL/min/1.73m2, or all-cause mortality). Exposure variables were circulating lipid profiles and lipid distribution measurements. Association were assessed using Relative risks (RRs) (95% confidence intervals (CIs)) computed by multivariate Poisson models combined with least absolute shrinkage and selection operator (LASSO) regression according to categories of lipid manifestations. The best model was selected via akaike information criterion (AIC), area under curve (AUC), receiver operating characteristic curve (ROC) and net reclassification index (NRI). Subgroup analysis and sensitivity analysis were performed to assess the interaction effects and robustness..

RESULTS

255 individuals reached the composite outcome. Median follow-up duration was 2.03 [1.06, 3.19] years. Median age was 58.8 [48.7, 67.2] years with a median eGFR of 33.7 [17.6, 47.8] ml/min/1.73 m2. Five dataset were built after multiple imputation and five category-based Possion models were constructed for each dataset. Model 5 across five datasets had the best fitness with smallest AIC and largest AUC. The pooled results of Model 5 showed that total cholesterol (TC) (RR (95%CI) (per mmol/L) :1.143[1.023,1.278], P = 0.018) and percentage of body fat (PBF) (RR (95%CI) (per percentage):0.976[0.961,0.992], P = 0.003) were significant factors of composite outcome. The results indicated that comprehensive consideration of lipid metabolism and fat distribution is more critical in the prediction of CKD prognosis..

CONCLUSION

Comprehensive consideration of lipid manifestations is optimal in predicting the prognosis of individuals with non-dialysis CKD stages 3-5.

Body mass index and weight change are associated with mortality in chronic kidney disease: A retrospective cohort study using a Japanese medical claims database

OBJECTIVES

This study aimed to investigate body mass index (BMI) and rate of weight change associated with adverse outcomes in Asian patients with chronic kidney disease.

METHODS

A retrospective cohort study was performed between April 2014 and June 2022 using the administrative claims database compiled by the Japan Medical Data Center. Patients were defined as individuals with comorbidities with chronic kidney disease stages 3 to 5 on admission and were aged ≥40 y with BMI at admission and BMI information from a previous admission 3 to 12 mo earlier. Restricted cubic spline analysis and thin-plate smoothed spline analysis were performed.

RESULTS

A total of 10 802 individuals were analyzed. The mean age was 74.6 ± 11.3 y, number of men was 7175 (66.4%), and 2115 (19.6%) deaths were recorded. Smoothed splines for BMI found that low BMI was associated with high hazard ratio (HR) (BMI = 18.5 kg/m2; HR = 1.3 [1.2-1.4]). Smoothed splines of weight change found higher HR with increasing rate of weight change for both weight gain and loss (weight change rate = -10%; HR = 1.4 [1.3-1.5]; weight change rate = 10%; HR = 1.2 [1.1-1.3]). In thin-plate smoothed spline analysis, the U-curve had a higher odds ratio as BMI decreased in patients with or without dialysis and as the degree of weight change increased.

CONCLUSIONS

We found trends in BMI and rate of weight change associated with mortality in Asian patients with chronic kidney disease.

Association Between Weight Change During Adulthood and Chronic Kidney Disease: Results from a National Survey 2011-2018

Purpose

This study aimed to investigate the intricate relationship between weight change patterns and the onset of chronic kidney disease (CKD). Although obesity is recognized as a predisposing factor for CKD, the dynamics of weight fluctuation and its impact on CKD development are not well-defined. By analyzing data from the National Health and Nutrition Examination Survey (NHANES) spanning 2011 to 2018, we sought to elucidate the association between weight trajectories and CKD risk.

Patients and Methods

We included participants aged ≥40 years, employing body mass index (BMI) measurements at three life stages-baseline, age 25, and a decade preceding baseline-to categorize weight change patterns. Logistic regression was employed to evaluate the association of these patterns with CKD onset, adjusting for potential confounders.

Results

The study encompassed 12,284 participants, with 2893 individuals diagnosed with CKD. Transitioning from normal weight to obesity and staying obese throughout adulthood were found to increase the risk of developing CKD. These associations remained consistent after adjusting for covariates but were statistically insignificant after adjusting for comorbidities. Notably, individuals transitioning from obesity to normal weight from age 25 to baseline and from 10 years before baseline to baseline demonstrated significant correlations with CKD but not between age 25 and 10 years before baseline.

Conclusion

Obesity, weight gain throughout adulthood, and weight loss in middle-to-late adulthood are associated with an increased risk of CKD. This emphasizes the importance of long-term weight change patterns and maintaining a healthy weight throughout adulthood.

Obesity Weight Loss Phenotypes in CKD: Findings From the Chronic Renal Insufficiency Cohort Study

Introduction

Although people with chronic kidney disease (CKD) and obesity have important motivations to lose weight, weight loss is also associated with health risks. We examined whether patterns of change in systolic blood pressure (SBP), serum albumin level, and fat-free mass (FFM) can help to differentiate between healthy and high-risk weight loss in this population.

Methods

Using data from the Chronic Renal Insufficiency Cohort Study (CRIC), we estimated a joint multivariate latent class model with 6 classes to identify distinct trajectories of body mass index (BMI), albumin, and SBP among participants with obesity (BMI ≥30 kg/m2 at baseline), accounting for informative missingness from death. In a secondary analysis, we fit a 6-class model with BMI and FFM.

Results

Among 2831 participants (median baseline BMI 35.6, interquartile range [IQR] 32.4-40.0 kg/m2), median follow-up was 6.8 (IQR 4.8-12.9) years, median age was 61 (IQR 54-67) years, 53% were male, 50% were non-Hispanic Black, and 82% were trying to control or lose weight at baseline. Latent classes were associated with mortality risk (5-year cumulative incidence of mortality 6.8% and 1.5% in class 6 and 3, respectively). Class 6 had the highest mortality rate and was characterized by early, steep BMI loss, early serum albumin decline, and late SBP increase. In the secondary analysis, a class characterized by steep BMI and FFM loss was associated with the highest death risk.

Conclusions

Among adults with CKD and obesity, BMI loss with concomitant serum albumin or FFM loss was associated with a high risk of death.

Chronic Kidney Disease and Obesity

There is a pandemic of obesity worldwide and in Europe up to 30% of the adult population is already obese. Obesity is strongly related to the risk of CKD, progression of CKD, and end-stage renal disease (ESRD), also after adjustment for age, sex, race, smoking status, comorbidities, and laboratory tests. In the general population, obesity increases the risk of death. In nondialysis-dependent CKD patients, the association between body mass index and weight with mortality is controversial. In ESRD patients, obesity is paradoxically associated with better survival. There are only a few studies investigating changes in weight in these patients and in most weight loss was associated with higher mortality. However, it is not clear if weight change was intentional or unintentional and this is an important limitation of these studies. Management of obesity includes life-style interventions, bariatric surgery, and pharmacotherapy. In the last 2 years, a long-acting glucagon-like peptide-1 (GLP-1) receptor agonist and GLP-1 and glucose-dependent insulinotropic polypeptide receptor agonist were shown to be effective in managing weight loss in non-CKD patients, but we are awaiting results of more definitive studies in CKD patients.

[Unintentional weight loss in chronic kidney disease]

If the causes of unintended weight loss are already diverse in pre-dialysis patients, at the stage of dialysis requirement a variety of other causes are added. Both stages share a trend towards loss of appetite and nausea, whereby uremic toxins certainly do not represent the only cause. In addition, both stages involve increased catabolism and therefore a higher calorie requirement. In the dialysis stage, protein loss (more in peritoneal dialysis than in hemodialysis) and the sometimes extensive dietary restrictions (low potassium, low phosphate, fluid restriction) are added. The problem of malnutrition, especially in dialysis patients, has been increasingly recognized in recent years, and there is a trend towards improvement. Initially, the causes of weight loss were subsumed under the terms protein energy wasting (PEW), which emphasized the protein loss in dialysis, and malnutrition-inflammation-atherosclerosis (MIA) syndrome, which highlighted chronic inflammation in dialysis patients; however, a variety of other factors contribute to weight loss, which are better described by the term chronic disease-related malnutrition (C-DRM). Weight loss is the most significant factor in recognizing malnutrition, as pre-existing obesity (especially type II diabetes mellitus) often makes the recognition more difficult. In the future, the increasing use of glucagon-like peptide 1 (GLP-1) agonists for weight loss could also lead to weight loss being perceived as intentional rather than distinguishing between intentional fat loss and unintentional loss of muscle mass.

The Impact of BMI Changes on the Incidence of Glomerular Hematuria in Korean Adults: A Retrospective Study Based on the NHIS-HEALS Cohort

Obesity and recurrent hematuria are known risk factors for chronic kidney disease. However, there has been controversy on the association between obesity and glomerular hematuria. This study aimed to investigate the association between body mass index (BMI) and weight change and recurrent and persistent hematuria in glomerular disease using a large-scale, population-based Korean cohort. Data were collected from the National Health Insurance Service-National Health Screening Cohort. Cox proportional hazards regression analysis was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for recurrent and persistent hematuria in glomerular disease according to the BMI group. Compared with the BMI 23-25 kg/m² group, the HR (95% CI) for incident recurrent and persistent hematuria in glomerular disease was 0.921 (0.831-1.021) in the BMI <23 kg/m² group, 0.915 (0.823-1.018) in the BMI 25-30 kg/m² group, and 1.151 (0.907-1.462) in the BMI ≥30 kg/m² group. Compared with the stable weight group, the HRs (95% CIs) for incident recurrent and persistent hematuria in glomerular disease were 1.364 (1.029-1.808) and 0.985 (0.733-1.325) in the significant weight loss and gain groups, respectively. Despite adjusting for confounders, this result remained significant. Baseline BMI was not associated with the risk of incident recurrent and persistent hematuria in glomerular disease. Weight loss greater than 10% was associated with the incidence of recurrent and persistent hematuria in glomerular disease. Therefore, maintaining an individual's weight could help prevent recurrent and persistent hematuria in glomerular disease in middle-aged and older Korean adults.

SRDA: Mobile Sensing based Fluid Overload Detection for End Stage Kidney Disease Patients using Sensor Relation Dual Autoencoder

Chronic kidney disease (CKD) is a life-threatening and prevalent disease. CKD patients, especially endstage kidney disease (ESKD) patients on hemodialysis, suffer from kidney failures and are unable to remove excessive fluid, causing fluid overload and multiple morbidities including death. Current solutions for fluid overtake monitoring such as ultrasonography and biomarkers assessment are cumbersome, discontinuous, and can only be performed in the clinic. In this paper, we propose SRDA, a latent graph learning powered fluid overload detection system based on Sensor Relation Dual Autoencoder to detect excessive fluid consumption of EKSD patients based on passively collected bio-behavioral data from smartwatch sensors. Experiments using real-world mobile sensing data indicate that SRDA outperforms the state-of-the-art baselines in both F1 score and recall, and demonstrate the potential of ubiquitous sensing for ESKD fluid intake management.

Changes in body composition in relation to estimated glomerular filtration rate and physical activity in predialysis chronic kidney disease

Background

Early body composition changes, associated with physical inactivity and disease advancement are devastating for patient-related outcomes in predialysis chronic kidney disease (CKD), thus warranting a detailed analysis of body composition beyond conventional measures.

Methods

The study included 40 subjects diagnosed with CKD; recruited between January to May 2021. Body composition was measured using the multifrequency analyzer, InBody 770. International Physical Activity Questionnaire-Short Form was used to assess physical activity. Suitable statistical analyses were performed using SPSS 21.0.

Results

The mean age of the subjects was 58.68 ± 12.24 years. Sarcopenic obesity was prevalent in 62.5% of the subjects. Body mass index under identified obesity by 15% compared to percent body fat, especially in subjects with low muscle mass. The decline in a unit of estimated glomerular filtration rate (eGFR) significantly correlated with a decrease in weight (p = 0.02), body fat mass (p = 0.05), visceral fat area (p = 0.05), and phase angle (p = 0.01) with marginal changes in waist-hip ratio and extracellular water/total body water. The effect of physical activity on skeletal muscle mass was homogeneous between low and moderate levels, but significantly different from high activity level.

Conclusion

Changes in fat and fluid compartment were associated with eGFR decline, whereas higher physical activity positively affected body composition.

Association of Intra-individual Differences in Estimated GFR by Creatinine Versus Cystatin C With Incident Heart Failure

RATIONALE & OBJECTIVE

Lower estimated glomerular filtration rate (eGFR) is associated with heart failure (HF) risk. However, eGFR based on cystatin C (eGFRcys) and creatinine (eGFRcr) may differ substantially within an individual. The clinical implications of these differences for risk of HF among persons with chronic kidney disease (CKD) are unknown.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

4,512 adults with CKD and without prevalent HF who enrolled in the Chronic Renal Insufficiency Cohort (CRIC) Study.

EXPOSURE

Difference in GFR estimates (eGFRdiff; ie, eGFRcys minus eGFRcr).

OUTCOME

Incident HF hospitalization.

ANALYTICAL APPROACH

Fine-Gray proportional subhazards regression was used to investigate the associations of baseline, time-updated, and slope of eGFRdiff with incident HF.

RESULTS

Of 4,512 participants, one-third had eGFRcys and eGFRcr values that differed by over 15 mL/min/1.73 m2. In multivariable-adjusted models, each 15 mL/min/1.73 m2 lower baseline eGFRdiff was associated with higher risk of incident HF hospitalization (hazard ratio [HR], 1.20 [95% CI, 1.07-1.34]). In time-updated analyses, those with eGFRdiff less than -15 mL/min/1.73 m2 had higher risk of incident HF hospitalization (HR, 1.99 [95% CI, 1.39-2.86]), and those with eGFRdiff ≥15 mL/min/1.73 m2 had lower risk of incident HF hospitalization (HR, 0.67 [95% CI, 0.49-0.91]) compared with participants with similar eGFRcys and eGFRcr. Participants with faster declines in eGFRcys relative to eGFRcr had higher risk of incident HF (HR, 1.49 [95% CI, 1.19-1.85]) compared with those in whom eGFRcys and eGFRcr declined in parallel.

LIMITATIONS

Entry into the CRIC Study was determined by eGFRcr, which constrained the range of baseline eGFRcr-but not eGFRcys-values.

CONCLUSIONS

Among persons with CKD who have large differences between eGFRcys and eGFRcr, risk for incident HF is more strongly associated with eGFRcys. Diverging slopes between eGFRcys and eGFRcr over time are also independently associated with risk of incident HF.

Nomogram model for predicting early onset of chronic kidney disease using color Doppler region of interest technique

PURPOSE

The risk factors of chronic kidney disease were analyzed by using the region of interest quantitative technology of color Doppler combined with QLab software, and a Nomogram was established to conduct an individualized assessment of patients with chronic kidney disease.

METHODS

A total of 500 patients with chronic kidney disease diagnosed in our hospital from June 2019 to March 2021 were selected as the chronic kidney disease group, and 300 healthy patients during the same period were selected as the control group. Univariate analysis was performed on the test indexes and the vascularity index, flow index, and vascularization flow index measured by the color doppler region of interest quantitative technique. The above meaningful indicators were included in the Logistics regression analysis to obtain the independent risk factors of early chronic kidney disease. The independent risk factors were imported into R software to draw a Nomogram model for predicting early chronic kidney disease and evaluate the model.

RESULTS

Single factor analysis results suggest age, hypertension, diabetes, hyperlipidemia, disease of heart head blood-vessel, body mass index, vascularity index, flow index, and vascularization flow index, fasting blood sugar, triglyceride, total cholesterol, urea nitrogen, creatinine, uric acid, glomerular filtration rate differences statistically significant (P < 0.05). Logistics regression analysis showed that hypertension, diabetes, flow index, and vascularization flow index, urea nitrogen, and albumin were independent risk factors for the early occurrence of chronic kidney disease. The C-index of this Nomogram using independent risk factors is 0.896 (95%CI 0.862-0.930), which indicates that the Nomogram has good discriminant power. The receiver operating curve of the histograph was area under the curve (AUC) 0.884 (95%CI 0.860-0.908). The receiver operator characteristic curve (ROC) of urea nitrogen, albumin, flow index, and vascularization flow index were evaluated. The results indicated that the best cutoff value of urea nitrogen was 5.9 mmol/L, flow index was 14.67, vascularization flow index was 4.6, and albumin was 40.26 g/L.

CONCLUSION

In the prediction of chronic kidney disease I-II stage, the quantitative technique of color Doppler region of interest has certain diagnostic value. The model established in this study has good discriminative power and can be applied to clinical practice, giving certain indicative significance.

Self-reported Physical Activity and Cardiovascular Events in Adults With CKD: Findings From the CRIC (Chronic Renal Insufficiency Cohort) Study

RATIONALE & OBJECTIVE

In the general population, there is an association between higher levels of physical activity and lower risk for cardiovascular events and mortality, but this relationship has not been well evaluated in chronic kidney disease (CKD). We investigated the association between self-reported physical activity and outcomes in a CKD cohort.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

3,926 participants in the Chronic Renal Insufficiency Cohort (CRIC) Study.

EXPOSURE

Time-updated self-reported physical activity assessed by (1) quartile of moderate-to-vigorous physical activity (MVPA) and (2) meeting guideline-recommended level of physical activity (categorized as active, meeting guidelines; active, not meeting guidelines; or inactive).

OUTCOME

Atherosclerotic events (myocardial infarction, stroke, or peripheral artery disease), incident heart failure, and all-cause and cardiovascular death.

ANALYTICAL APPROACH

Cox proportional hazards regression.

RESULTS

At baseline, compared with the lowest MVPA quartile, those in the highest quartile were more likely to be younger, male, not have prevalent cardiovascular disease, and have higher estimated glomerular filtration rate. Overall, 51% met the physical activity guidelines; of those who did not, 30% were inactive. During the median follow-up period of 13.4 years, there were 772 atherosclerotic events, 848 heart failure events, and 1,553 deaths, and 420 cardiovascular deaths. Compared with the participants in the lowest MVPA quartile, the highest quartile had a lower risk of atherosclerotic events (HR, 0.64 [95% CI, 0.51-0.79]), incident heart failure (HR, 0.71 [95% CI, 0.58-0.87]), and all-cause and cardiovascular death (HRs of 0.54 [95% CI, 0.46-0.63] and 0.47 [95% CI, 0.35-0.64], respectively). The findings were similar for analyses evaluating recommended level of physical activity.

LIMITATIONS

Self-reported physical activity may result in some degree of misclassification.

CONCLUSIONS

Higher self-reported physical activity was associated with lower risk of cardiovascular events and mortality in CKD patients, which may have important implications for clinical practice and the design of interventional studies.

PLAIN-LANGUAGE SUMMARY

In this long-term study of 3,926 adults with chronic kidney disease, we found that individuals with higher levels of physical activity were less likely to experience an atherosclerotic event (for example, a heart attack, stroke, or peripheral arterial disease), new-onset heart failure, and death as compared with those with lower levels of physical activity. The findings were similar for the analyses evaluating adherence to guideline-recommended level of physical activity (that is, for more than 150 minutes per week), and they strengthen the evidence supporting the current guideline recommendations.

The relationship between anthropometric indicators and health-related quality of life in a community-based adult population: A cross-sectional study in Southern China

Background

This study was designed to analyze the relationship of waist circumference (WC), body mass index (BMI), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), relative fat mass (RFM), lipid accumulation product (LAP) and health-related quality of life (HRQoL) in the community-dwelling population of southern China and to explore the independent contribution of socio-demographic characteristics, number of chronic diseases and anthropometric indicators to HRQoL in that population.

Methods

This community-based cross-sectional survey studied 2,663 adults aged 18 years and older. HRQoL was assessed by the 3-level EuroQol 5-dimensional scale (EQ-5D-3L), and HRQoL were calculated using the Chinese EQ-5D-3L value set. The outcome variable was the EQ-5D-3L score (HRQoL). Cluster regression was used to analyse the independent contribution of each obesity indicator to HRQoL.

Results

A total of 2,663 people participated in this study, and their mean EQ-5D-3L score was 0.938 ± 0.072. In this study, according to the results of the one-way ANOVA, HRQoL was significantly different between the groups of WHtR, WHR, RFM and LAP, respectively. The independent contributions of socio-demographic factors, number of chronic diseases and anthropometric measures to HRQoL in the whole population accounted for 76.2, 7.9, and 15.9% of the total effect, respectively.

Conclusion

RFM and LAP were found to have a previously unreported negative impact on HRQoL in a community-dwelling population. In future studies, RFM and LAP could be used as new indicators of obesity to predict quality of life in humans.

Normal weight and waist obesity indicated by increased total body fat associated with all-cause mortality in stage 3–5 chronic kidney disease

Patients with chronic kidney disease (CKD) demonstrate a survival benefit with a high body mass index (BMI); this is the obesity paradox. Central obesity has a higher prognostic value than BMI, even in those with normal weight. Whether total body fat percentage (TBF%) provides more information than BMI and waist circumference (WC) remains unknown. We included 3,262 Asian patients with stage 3–5 CKD and divided these patients by TBF% and waist-to-height ratio (WHtR) quartiles (Q1–Q4). TBF% was associated with BMI, WC, nutritional markers, and C-reactive protein. In all patients, BMI but not TBF% or WHtR demonstrated a survival paradox. In patients with BMI &lt;25 kg/m2, but not in those with BMI ≥ 25 kg/m2, TBF% Q4 and WHtR Q4 were associated with all-cause mortality, with hazard ratios [HRs; 95% confidence intervals (CIs)] of 2.35 (1.31–4.22) and 1.38 (1.06–1.80), respectively. The HRs of TBF% Q4 for all-cause mortality were 2.90 (1.50–5.58) in patients with a normal WC and 3.81 (1.93–7.50) in patients with normal weight and normal WC (All P for interaction &lt; 0.05). In conclusion, TBF% can predict all-cause mortality in patients with advanced CKD and a normal weight, normal WC, or both.

Modifiable Lifestyle Behaviors and CKD Progression: A Narrative Review

Living a healthy lifestyle is one of the safest and most cost-effective ways to improve one's quality of life and prevent and/or manage chronic disease. As such, current CKD management guidelines recommend that patients adhere to a healthy diet, perform ≥150 minutes per week of physical activity, manage their body weight, abstain from tobacco use, and limit alcohol. However, there are limited studies that investigate the relationship between these lifestyle factors and the progression of CKD among people with established CKD. In this narrative review, we examine the reported frequencies of health lifestyle behavior engagement among individuals with non-dialysis-dependent CKD and the existing literature that examines the influences of diet, physical activity, weight management, alcohol consumption, and tobacco use on the progression of CKD, as measured by decline in GFR, incident ESKD, or elevated proteinuria or albuminuria in individuals with CKD. Many of the available studies are limited by length of follow-up and small sample sizes, and meta-analyses were limited because the studies were sparse and had heterogeneous classifications of behaviors and/or referent groups and of CKD progression. Further research should be done to determine optimal methods to assess behaviors to better understand the levels at which healthy lifestyle behaviors are needed to slow CKD progression, to investigate the effect of combining multiple lifestyle behaviors on important clinical outcomes in CKD, and to develop effective techniques for behavior change. Despite the lack of evidence of efficacy from large trials on the ability of lifestyle behaviors to slow CKD progression, maintaining a healthy lifestyle remains a cornerstone of CKD management given the undisputed benefits of healthy lifestyle behaviors on cardiovascular health, BP control, and survival.

Association of Intraindividual Difference in Estimated Glomerular Filtration Rate by Creatinine vs Cystatin C and End-stage Kidney Disease and Mortality

Importance

As cystatin C is increasingly adopted to estimate glomerular filtration rate (eGFR), clinicians will encounter patients in whom cystatin C-based eGFR (eGFRcys) and creatinine-based eGFR (eGFRcr) differ widely. The clinical implications of these differences, eGFRdiffcys-cr, are unknown.

Objective

To evaluate the associations of eGFRdiffcys-cr with end-stage kidney disease (ESKD) and mortality among individuals with chronic kidney disease (CKD).

Design, Setting, and Participants

This is a prospective cohort study of 4956 individuals with mild to moderate CKD from 7 clinical centers in the United States who enrolled in the Chronic Renal Insufficiency Cohort (CRIC) Study between 2003 to 2018. Statistical analyses were completed in December 2021.

Exposures

eGFRdiffcys-cr (eGFRcys - eGFRcr) was calculated at baseline and annually thereafter for 3 years. Because 15 mL/min/1.73 m2 represents a clinically meaningful difference in eGFR that also distinguishes CKD stages, eGFRdiffcys-cr was categorized as: less than -15 mL/min/1.73 m2, -15 to 15 mL/min/1.73 m2, and 15 mL/min/1.73 m2 or greater.

Main Outcomes and Measures

The outcomes of ESKD, defined as initiation of maintenance dialysis or receipt of a kidney transplant, and all-cause mortality were adjudicated from study entry until administrative censoring in 2018.

Results

Among 4956 participants with mean (SD) age of 59.5 (10.5) years, 2152 (43.4%) were Black, 515 (10.4%) were Hispanic, and 2113 (42.6%) were White. There were 2156 (43.5%) women and 2800 (56.5%) men. At baseline, eGFRcys and eGFRcr values differed by more than 15 mL/min/1.73 m2 in one-third of participants (1638 participants [33.1%]). Compared with participants with similar baseline eGFRcys and eGFRcr (eGFRdiffcys-cr -15 to 15 mL/min/1.73 m2), those in whom eGFRcys was substantially lower than eGFRcr (eGFRdiffcys-cr < -15 mL/min/1.73 m2) had a higher risk of mortality (hazard ratio [HR], 1.86; 95% CI, 1.40-2.48) while those with eGFRdiffcys-cr of 15 mL/min/1.73 m2 or greater had lower risks of ESKD (subHR [SHR], 0.73; 95% CI, 0.59-0.89) and mortality (HR, 0.68; 95% CI, CI 0.58-0.81). In time-updated analyses, participants with eGFRdiffcys-cr less than -15 mL/min/1.73 m2 had higher risks of ESKD (SHR, 1.83; 95% CI, 1.10-3.04) and mortality (HR, 3.03; 95% CI, 2.19-4.19) compared with participants with similar eGFRcys and eGFRcr. Conversely, participants with eGFRdiffcys-cr of 15 mL/min/1.73 m2 or greater had lower risks of ESKD (SHR, 0.50; 95% CI, 0.35-0.71) and mortality (HR, 0.58; 95% CI, 0.45-0.75). Longitudinal changes in eGFRdiffcys-cr were associated with mortality risk. Compared with participants who had similar slopes by eGFRcys and eGFRcr, those with smaller eGFRcr declines had an 8-fold increased mortality risk (HR, 8.20; 95% CI, 6.37-10.56), and those with larger apparent declines by eGFRcr had a lower mortality risk (HR, 0.14; 95% CI, 0.08-0.24).

Conclusions and Relevance

These findings suggest that large differences between eGFRcys and eGFRcr were common in persons with CKD. These differences and their changes over time may be informative of ESKD and mortality risks, warranting monitoring of both eGFRcys and eGFRcr in this high-risk population.

Trajectories of Nutritional Parameters Before and After Prescribed Oral Nutritional Supplements: A Longitudinal Cohort Study of Patients With Chronic Kidney Disease Not Requiring Dialysis

Background:

The association between oral nutritional supplement use and nutritional parameters among patients with nondialysis chronic kidney disease (CKD-ND) with or at high risk of undernutrition/protein-energy wasting has not been previously studied. The definition of patient subgroups most likely to benefit from oral nutritional supplementation (ONS) is also an area where more research is needed.

Objective:

To assess nutritional parameter trajectories among patients with CKD-ND prescribed oral nutritional supplements in British Columbia, and to compare trajectories by nutritional phenotype.

Design:

Longitudinal cohort study, pre-post design.

Setting:

Multidisciplinary CKD clinics across British Columbia.

Patients:

A total of 3957 adult patients with CKD-ND, who entered multidisciplinary CKD clinics during 2010 to 2019, met criteria for oral nutritional supplement prescription based on dietitian assessment, and received ≥1 oral nutritional supplement prescription.

Measurements:

Longitudinal nutritional parameters, including body mass index (BMI), serum albumin, serum bicarbonate, serum phosphate, and neutrophil-to-lymphocyte ratio (NLR).

Methods:

Using linear mixed models, slopes for nutritional and inflammation parameters were assessed in the 2-year periods before and after the first oral nutritional supplement prescription. Hierarchical cluster analysis was applied to identify nutritional phenotypes using baseline data, and slope analysis was repeated by cluster.

Results:

In the pre-oral-nutritional-supplement period, declines in BMI (−0.87 kg/m2/year, 95% confidence interval [CI]: −0.99 to −0.75), albumin (−1.11 g/L/year, 95% CI: −1.27 to −0.95), and bicarbonate (−0.49 mmol/L/year; 95% CI: −0.59 to −0.39), and increases in NLR (+0.79/year; 95% CI: 0.60 to 0.98) and phosphate (+0.05 mmol/L/year; 95% CI: 0.04 to 0.06) were observed. Following oral nutritional supplement prescription, there were statistically significant increases in BMI slope (+0.91 kg/m2/year, P < .0001), albumin slope (+0.82 g/L/year, P < .0001), and phosphate slope (+0.02 mmol/L/year, P = .005), as well as a decline in NLR slope of −0.55/year ( P < .0001). There was no significant change in bicarbonate slope. Cluster analysis identified 5 distinct phenotypes. The cluster with the highest mean baseline NLR and lowest mean BMI demonstrated the greatest number of improvements in nutritional parameter slopes in the post-oral-nutritional-supplement period.

Limitations:

Possibility of residual confounding. Data on dietary intake, muscle mass, and nutritional scoring systems were not available in the registry.

Conclusions:

Among patients with CKD-ND prescribed oral nutritional supplements, there were improvements in nutrition/inflammation parameters over time following the first ONS prescription. The heterogeneity in response to ONS by cluster subgroup suggests an individualized approach to nutritional management may be beneficial.

Undernutrition and Hypoleptinemia Modulate Alloimmunity and CMV-specific Viral Immunity in Transplantation

BACKGROUND

Immunological mechanisms linking undernutrition to infection and the alloimmune response are poorly understood in transplantation. We aimed to determine how undernutrition and hypoleptinemia impact T-cell allospecific and cytomegalovirus (CMV) viral-specific immunity in a murine model.

METHODS

Fed, fasted for 48 h (model of undernutrition), and fasted with leptin injections (leptin rescue), C57BL/6 mice received skin grafts from either C57BL/6 (syngeneic) or BALB/c (allogeneic) mice donors. Allograft rejection and survival were monitored. Fed, fasted, and leptin rescue C57BL/6 mice were inoculated with murine cytomegalovirus (mCMV). Mouse spleens were retrieved for T-cell flow cytometry analysis, mCMV DNA extraction, and quantitative polymerase chain reaction. Serum leptin levels were measured with ELISA.

RESULTS

Fasted mice had prolonged rejection-free and graft survival compared with fed mice (P = 0.0002 and P = 0.043). Leptin administration did not alter rejection-free survival or allograft failure. CD8+ central memory T cell and CD8+ effector T cell proportions were significantly lower in fasted mice receiving allogeneic skin transplants compared with fed mice (P = 0.0009 and P = 0.0015). Fasted mice had higher viral loads (P = 0.0028) and impaired mCMV-specific interferon-gamma-producing CD8+ T cells (P = 0.0007), which improved with leptin rescue (P = 0.032).

CONCLUSIONS

Undernutrition and its associated hypoleptinemia correlated with impaired allospecific and viral-specific immunities. Leptin administration decreased mCMV viral burden and increased mCMV-specific T-cell immunity, however, it did not increase rejection or worsen graft survival in complete major histocompatibility complex-mismatched skin allografts. Leptin may be a potential adjunctive therapy for CMV viremia in undernourished transplant recipients.

Obesity Management in Kidney Transplant Candidates: Current Paradigms and Gaps in Knowledge

In this review, we discuss the increasing prevalence of obesity among people with chronic and end-stage kidney disease (ESKD) and implications for kidney transplant (KT) candidate selection and management. Although people with obesity and ESKD receive survival and quality-of-life benefits from KT, most KT programs maintain strict body mass index (BMI) cutoffs to determine transplant eligibility. However, BMI does not distinguish between visceral adiposity, which confers higher cardiovascular risks and risks of perioperative and adverse posttransplant outcomes, and muscle mass, which is protective in ESKD. Furthermore, requirements for patients with obesity to lose weight before KT should be balanced with the findings of numerous studies that show weight loss is a risk factor for death among patients with ESKD, independent of starting BMI. Data suggest that KT is associated with survival benefits relative to remaining on dialysis for candidates with obesity although recipients without obesity have higher delayed graft function rates and longer transplant hospitalization durations. Research is needed to determine the optimal body composition metrics for KT candidacy assessments and risk stratification. In addition, ESKD-specific obesity management guidelines are needed that will address the neurologic, behavioral, socioeconomic, and physical underpinnings of this increasingly common disease.

Increased Risk of Chronic Kidney Disease Associated With Weight Gain in Healthy Adults: Insight From Metabolic Profiles and Body Composition

Objective: Obesity is an established risk factor for kidney damage. In this study, we explored the long-term association of changes in body mass index (BMI) over time with incident chronic kidney disease (CKD).

Methods: For this analysis, 5,393 middle-aged adults without comorbidities in the Korean Genome and Epidemiology Study (KoGES) were included. Group-based trajectory modeling was used to determine the patterns of BMI change (decreasing, stable, and increasing BMI) between baseline and year 4. The primary outcome was the subsequent development of CKD from year 4. A multivariable Cox proportional hazards model was constructed to determine the risk of incident CKD according to BMI trajectories.

Results: During 55,327 person-years, incident CKD occurred in 354 (6.5%) participants; 6.0, 6.1, and 7.8 per 1,000 person-years across the trajectories, respectively (P = 0.005). In the multivariable-adjusted Cox proportional hazards model, the increasing BMI trajectory was associated with a 1.4-fold [hazard ratio (HR), 1.41; 95% CI, 1.06–1.87] a higher risk of incident CKD compared with stable BMI trajectory. This association was stronger for overweight and obese individuals. The HRs for CKD development in these two groups were 1.6 (95% CI, 1.06–1.87) and 2.2 (95% CI, 1.40–3.48), respectively. While the increasing BMI group was gaining weight, there were concomitant increases in blood pressure, insulin resistance, serum concentrations of total cholesterol, triglyceride, and high-sensitivity C-reactive protein (hs-CRP), and fat mass, but high-density lipoprotein (HDL)-cholesterol level and muscle-to-fat (MF) ratio decreased.

Conclusion: Weight gain is associated with an increased risk of incident CKD in healthy adults. This association is attributed to worsening metabolic profiles and increasing fat mass.

Frailty in Pancreas Transplantation

There are a variety of definitions and criteria used in clinical practice to define frailty. In the absence of a gold-standard definition, frailty has been operationally defined as meeting 3 out of 5 phenotypic criteria indicating compromised function: low grip strength, low energy, slowed walking speed, low physical activity, and unintentional weight loss. Frailty is a common problem in solid organ transplant candidates who are in the process of being listed for a transplant, as well as after transplantation. Patients with diabetes or chronic kidney disease (CKD) are known to be at increased risk of being frail. As pancreas transplantation is exclusively performed among patients with diabetes and the majority of them also have CKD, pancreas transplant candidates and recipients are at high risk of being frail. Sarcopenia, fatigue, low walking speed, low physical activity, and unintentional weight loss, which are some of the phenotypes of frailty, are very prevalent in this population. In various solid organs, frail patients are less likely to be listed or transplanted and have high waitlist mortality. Even after a transplant, they have increased risk of prolonged hospitalization, readmission, and delayed graft function. Given the negative impact of frailty on solid organ transplants, we believe that frailty would have a similar or even worse impact on pancreas transplantation. Due to the paucity of data specifically among pancreas transplant recipients, here we include frailty data from patients with CKD, diabetes, and various solid organ transplant recipients.

Risk Factors Influencing the Outcomes of Kidney Re-Transplantation

BACKGROUND Our kidney transplant waitlist includes 20% re-transplantations (TX2). Knowing what to expect is a clinical obligation. MATERIAL AND METHODS We compared graft and patient survival of all 162 TX2 patients, transplanted 2000 to 2009, with 162 patients after first transplantation (TX1) matched for age, sex, living/non-living donation, and transplantation date. Patient follow-up was 10 years. RESULTS TX2 graft and patient survivals were inferior to TX1 (p<0.001 and p=0.047). TX2 patients had a longer cumulative dialysis vintage, more human leucocyte antigen (HLA) mismatches, more panel-reactive HLA antibodies, more often received induction therapy with rabbit-antithymocyte globulin (rATG), and had a lower body mass index (all p<0.05). Death from infection and graft failure by rejection was more frequent after TX2 (both p<0.05) but not after TX1. Multivariable Cox regression analysis revealed that both cohorts had graft failure and death risk associated with infection and cardiovascular disease, and graft failure by humoral rejection. However, only TX2 patients had an additional risk of graft failure with early inferior graft function and of patient death with ≥2 comorbidities. Moreover, Kaplan-Meier analysis showed that TX2 and not TX1 patients had a lower graft and patient survival associated with infection and with ≥2 comorbidities (all p<0.05). CONCLUSIONS Re-transplantation is associated with worse graft outcomes mainly because of immunologic and graft-quality reasons, although the high number of comorbidities and infection severities aside from cardiovascular disease drive mortality. The more frequent rATG induction of TX2 patients could promote infection by enhancing immunosuppression. By addressing comorbidities, outcomes could possibly be improved.

Patient-Reported Measures and Lifestyle Are Associated With Deterioration in Nutritional Status in CKD Stage 4-5: The EQUAL Cohort Study

OBJECTIVE

The aim of this study was to explore the changes in nutritional status before dialysis initiation and to identify modifiable risk factors of nutritional status decline in older adults with advanced renal disease.

DESIGN AND METHODS

The European Quality Study on treatment in advanced chronic kidney disease (EQUAL) is a prospective, observational cohort study involving six European countries. We included 1,103 adults >65 years with incident estimated glomerular filtration rate <20 mL/min/1.73 m² not on dialysis, attending nephrology care. Nutritional status was assessed with the 7-point Subjective Global Assessment tool (7-p SGA), patient-reported outcomes with RAND-36 and the Dialysis Symptom Index. Logistic regression was used to estimate the associations between potential risk factors and SGA decline.

RESULTS

The majority of the patients had a normal nutritional status at baseline, 28% were moderately malnourished (SGA ≤5). Overall, mean SGA decreased by -0.18 points/year, (95% confidence interval -0.21; -0.14). More than one-third of the study participants (34.9%) deteriorated in nutritional status (1 point decline in SGA) and 10.9% had a severe decline in SGA (≥2 points). The proportion of patients with low SGA (≤5) increased every 6 months. Those who dropped in SGA also declined in estimated glomerular filtration rate and mental health score. Every 10 points decrease in physical function score increased the odds of decline in SGA by 23%. Lower physical function score at baseline, gastrointestinal symptoms, and smoking were risk factors for impaired nutritional status. There was an interaction between diabetes and physical function on SGA decline.

CONCLUSIONS

Nutritional status deteriorated in more than one-third of the study participants during the first year of follow-up. Lower patient-reported physical function, more gastrointestinal symptoms, and current smoking were associated with decline in nutritional status.

Pre-Kidney Transplant Unintentional Weight Loss Leads to Worse Post-Kidney Transplant Outcomes

BACKGROUND

Weight loss before kidney transplant (KT) is a known risk factor for weight gain and mortality; however, whereas unintentional weight loss is a marker of vulnerability, intentional weight loss might improve health. We tested whether pre-KT unintentional and intentional weight loss have differing associations with post-KT weight gain, graft loss, and mortality.

METHODS

Among 919 KT recipients from a prospective cohort study, we used adjusted mixed effects models to estimate post-KT BMI trajectories, and Cox models to estimate death-uncensored graft loss, death-censored graft loss, and all-cause mortality by one-year pre-KT weight change category [stable weight (change≤5%), intentional weight loss (loss>5%), unintentional weight loss (loss>5%), and weight gain (gain>5%)].

RESULTS

Mean age was 53 years, 38% were Black, and 40% were female. In the pre-KT year, 62% of recipients had stable weight, 15% had weight gain, 14% had unintentional weight loss, and 10% had intentional weight loss. In the first three years post-KT, BMI increases were similar among those with pre-KT weight gain and intentional weight loss, and lower compared to those with unintentional weight loss (difference +0.79 kg/m2/year, 95% CI: 0.50-1.08 kg/m2/year, p < 0.001). Only unintentional weight loss was independently associated with higher death-uncensored graft loss (adjusted Hazard Ratio [aHR]=1.80, 95% CI:1.23-2.62), death-censored graft loss (aHR=1.91, 95% CI:1.12-3.26) and mortality (aHR=1.72, 95% CI:1.06-2.79) relative to stable pre-KT weight.

CONCLUSIONS

This study suggests that unintentional, but not intentional, pre-KT weight loss is an independent risk factor for adverse post-KT outcomes.

Rapid Weight Change Over Time Is a Risk Factor for Adverse Outcomes in Patients With Predialysis Chronic Kidney Disease: A Prospective Cohort Study

OBJECTIVE

Both obesity and being underweight are risk factors for adverse outcomes in chronic kidney disease (CKD) patients. However, the effects of longitudinal weight changes on patients with predialysis CKD have not yet been studied. In this study, we analyzed the effects of weight change over time on the adverse outcomes in predialysis CKD population.

METHODS

Longitudinal data from a multicenter prospective cohort study (KNOW-CKD) were analyzed. In a total of 2,022 patients, the percent weight change per year were calculated using regression analysis and the study subjects were classified into five categories: group 1, ≤ -5%/year; group 2, -5< to ≤ -2.5%/year; group 3, -2.5< to <2.5%/year; group 4, 2.5≤ < 5%/year; and group 5, ≥5%/year. The incidences of end-stage renal disease (ESRD) and the composite outcome of cardiovascular disease (CVD) and death were calculated in each group and compared to group 3 as reference.

RESULTS

During a median 4.4 years of follow-up, 414 ESRD, and 188 composite of CVD and mortality events occurred. Both weight gain and loss were independent risk factors for adverse outcomes. There was a U-shaped correlation between the degree of longitudinal weight change and ESRD (hazard ratio 3.61, 2.15, 1.86 and 3.66, for group 1, 2, 4 and 5, respectively) and composite of CVD and death (hazard ratio 2.92, 2.15, 1.73 and 2.54, respectively), when compared to the reference group 3. The U-shape correlation was most prominent in the subgroup of estimated glomerular filtration rate <45 mL/min/1.73 m².

CONCLUSION

Both rapid weight gain and weight loss are associated with high risk of adverse outcomes, particularly in the advanced CKD.

Hand Grip and Leg Muscle Strength in Hemodialysis Patients and Its Determinants

BACKGROUND

Chronic kidney disease is associated with chronic inflammation and progressive loss of peripheral muscle strength and the ability to exercise, and these changes are highly pronounced in patients receiving hemodialysis (HD). We evaluated hand grip strength (HGS) and leg muscle strength (LMS) in patients receiving HD and attempted to identify factors associated with muscle strength.

METHODS

We screened HGS (opposite the fistula side) and LMS (both sides) in HD patients at a single center (n = 112) by using digital hand and leg dynamometers (T.K.K. 5401 and 5710e/5715, Takei Scientific Instruments Co. Ltd., Niigata, Japan).

RESULTS

The mean age of patients was 62.6 years, and 73.2% of the patients were male. Diabetes was the cause of kidney failure in 50% of the patients, and the median HD vintage was 34 months. A total of 77.7% of patients reported that they participated in regular home-based exercise, and 29.5% of patients regularly participated in hospital-based resistance exercise. HGS and LMS showed good correlation (r = 0.715, P < 0.001). HGS (25.1 vs. 17.0 kg) and LMS (30.1 vs. 20.4 kg) were greater in males (P < 0.001 and P < 0.001, respectively) than in females. Older patients (≥ 60 years) showed less LMS than younger patients in both males and females (P = 0.012 and P = 0.037, respectively), but HGS did not differ according to age. Patients performing regular home- or hospital-based exercise showed higher HGS than those who did not exercise (24.2 vs. 18.6 kg, P = 0.011), but LMS was not significantly different (29.3 vs. 23.6 kg, P = 0.185). Multiple linear regression analysis proved that male sex, younger age, and any type of exercise were factors associated with improved HGS and LMS. Groups of older age (≥ 60 years), male sex, and shorter duration of HD (< median) benefitted more from exercise.

CONCLUSION

Sex, age, and exercise were the most important determinants of muscle strength in HD patients. We need to encourage patients to engage in regular home or group exercise from the beginning of dialysis and introduce new feasible forms of exercise for HD patients.

Positive and Negative Aspects of Sodium Intake in Dialysis and Non-Dialysis CKD Patients

Sodium intake theoretically has dual effects on both non-dialysis chronic kidney disease (CKD) patients and dialysis patients. One negatively affects mortality by increasing proteinuria and blood pressure. The other positively affects mortality by ameliorating nutritional status through appetite induced by salt intake and the amount of food itself, which is proportional to the amount of salt under the same salty taste. Sodium restriction with enough water intake easily causes hyponatremia in CKD and dialysis patients. Moreover, the balance of these dual effects in dialysis patients is likely different from their balance in non-dialysis CKD patients because dialysis patients lose kidney function. Sodium intake is strongly related to water intake via the thirst center. Therefore, sodium intake is strongly related to extracellular fluid volume, blood pressure, appetite, nutritional status, and mortality. To decrease mortality in both non-dialysis and dialysis CKD patients, sodium restriction is an essential and important factor that can be changed by the patients themselves. However, under sodium restriction, it is important to maintain the balance of negative and positive effects from sodium intake not only in dialysis and non-dialysis CKD patients but also in the general population.

Body Composition Changes Following Dialysis Initiation and Cardiovascular and Mortality Outcomes in CRIC (Chronic Renal Insufficiency Cohort): A Bioimpedance Analysis Substudy

Rationale & Objective

Bioelectrical impedance analysis (BIA) provides a noninvasive assessment of body composition. BIA measures of nutritional (phase angle) and hydration (vector length) status are associated with survival among individuals with chronic kidney disease (CKD), including those receiving maintenance dialysis. However, little is known regarding changes in these parameters with CKD following the high-risk transition to maintenance dialysis.

Study Design

Observational study.

Settings & Participants

427 adults enrolled in the Chronic Renal Insufficiency Cohort (CRIC) Study, with BIA measurements performed within 1 year before and after initiation of maintenance dialysis.

Exposures

We calculated the changes in vector length and phase angle for patients with CKD transitioning to maintenance dialysis.

Outcomes

We examined the association of changes in vector length and phase angle during the transition to maintenance dialysis with risk for all-cause mortality or nonfatal myocardial infarction, stroke, or heart failure, adjusting for demographics, comorbid conditions, and nutritional parameters.

Results

Mean age was 58 ± 12 years and mean estimated glomerular filtration rate using the CKD Epidemiology Collaboration equation before dialysis initiation was 17.0 ± 8.7 mL/min/1.73 m². After covariate adjustment, mean changes in vector length and phase angle were 18 (95% CI, 7 to 30) Ω/m and -0.6  (95% CI, -1.3  to 0.1 ), respectively. Changes in both BIA parameters were not associated with risk for heart failure, stroke, myocardial infarction, or all-cause mortality: HR, 1.02 (95% CI, 0.91-1.14) per 1-SD increment in change for vector length and HR, 1.11 (95% CI, 0.88-1.41) per 1-SD increment in change for phase angle.

Limitations

Observational study, relatively small sample size.

Conclusions

In a multicenter cohort of patients with CKD who progressed to kidney failure, the transition to maintenance dialysis was associated with changes in body composition reflecting poorer cellular integrity and improved volume control. However, these longitudinal changes were not associated with adverse clinical events after dialysis initiation.

Physiologically based pharmacokinetic model of renally cleared antibacterial drugs in Chinese renal impairment patients

To preliminarily develop physiologically based population models for Chinese renal impairment patients and to evaluate the prediction performance of new population models by renally cleared antibacterial drugs. First, demographic data and physiological parameters of Chinese renal impairment patients were collected, and then the coefficients of the relative demographic and physiological equation were recalibrated to construct the new population models. Second, drug‐independent parameters of ceftazidime, cefodizime, vancomycin, and cefuroxime were collected and verified by Chinese healthy volunteers, Caucasian healthy volunteers, and Caucasian renal impairment population models built in Simcyp. Finally, the newly developed population models were applied to predict the plasma concentration of four antibacterial drugs in Chinese renal impairment patients. The new physiologically based pharmacokinetic (PBPK) population models can predict the main pharmacokinetic parameters, including area under the plasma concentration–time curve extrapolated to infinity (AUC_inf), renal clearance (CL_r), and peak concentration (C_max), of ceftazidime, cefodizime, vancomycin, and cefuroxime following intravenous administrations with less than twofold error in mild, moderate, and severe Chinese renal impairment patients. The accuracy and precision of the predictions were improved compared with the Chinese healthy volunteers and Caucasian renal impairment population models. The PBPK population models were preliminarily developed and the first‐step validation results of four antibacterial drugs following intravenous administration showed acceptable accuracy and precision. The population models still need more systematic validation by using more drugs and scenarios in future studies to support their applications on dosage recommendation for Chinese renal impairment patients.

Caloric Intake in Renal Patients: Repercussions on Mineral Metabolism

The aim of this paper is to review current knowledge about how calorie intake influences mineral metabolism focussing on four aspects of major interest for the renal patient: (a) phosphate (P) handling, (b) fibroblast growth factor 23 (FGF23) and calcitriol synthesis and secretion, (c) metabolic bone disease, and (d) vascular calcification (VC). Caloric intake has been shown to modulate P balance in experimental models: high caloric intake promotes P retention, while caloric restriction decreases plasma P concentrations. Synthesis and secretion of the phosphaturic hormone FGF23 is directly influenced by energy intake; a direct correlation between caloric intake and FGF23 plasma concentrations has been shown in animals and humans. Moreover, in vitro, energy availability has been demonstrated to regulate FGF23 synthesis through mechanisms in which the molecular target of rapamycin (mTOR) signalling pathway is involved. Plasma calcitriol concentrations are inversely proportional to caloric intake due to modulation by FGF23 of the enzymes implicated in vitamin D metabolism. The effect of caloric intake on bone is controversial. High caloric intake has been reported to increase bone mass, but the associated changes in adipokines and cytokines may as well be deleterious for bone. Low caloric intake tends to reduce bone mass but also may provide indirect (through modulation of inflammation and insulin regulation) beneficial effects on bone. Finally, while VC has been shown to be exacerbated by diets with high caloric content, the opposite has not been demonstrated with low calorie intake. In conclusion, although prospective studies in humans are needed, when planning caloric intake for a renal patient, it is important to take into consideration the associated changes in mineral metabolism.

Therapeutic potential of human induced pluripotent stem cells and renal progenitor cells in experimental chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) is a global public health problem. Cell therapy using pluripotent stem cells represents an attractive therapeutic approach for the treatment of CKD.

METHODS

We transplanted mitomycin C (MMC)-treated human induced pluripotent stem cells (hiPSCs) and renal progenitor cells (RPCs) into a CKD rat model system. The RPC and hiPSC cells were characterized by immunofluorescence and qRT-PCR. Untreated 5/6 nephrectomized rats were compared to CKD animals receiving the same amount of MMC-treated hiPSCs or RPCs. Renal function, histology, and immunohistochemistry were evaluated 45 days post-surgery.

RESULTS

We successfully generated hiPSCs from peripheral blood and differentiated them into RPCs expressing renal progenitor genes (PAX2, WT1, SIX2, and SALL1) and podocyte-related genes (SYNPO, NPHS1). RPCs also exhibited reduced OCT4 expression, confirming the loss of pluripotency. After cell transplantation into CKD rats, the body weight change was significantly increased in both hiPSC and RPC groups, in comparison with the control group. Creatinine clearance (CCr) was preserved only in the hiPSC group. Similarly, the number of macrophages in the kidneys of the hiPSC group reached a statistically significant reduction, when compared to control rats. Both treatments reduced positive staining for the marker α-smooth muscle actin. Histological features showed decreased tubulointerstitial damage (interstitial fibrosis and tubular atrophy) as well as a reduction in glomerulosclerosis in both iPSC and RPC groups.

CONCLUSIONS

In conclusion, we describe that both MMC-treated hiPSCs and RPCs exert beneficial effects in attenuating CKD progression. Both cell types were equally efficient to reduce histological damage and weight loss caused by CKD. hiPSCs seem to be more efficient than RPCs, possibly due to a paracrine effect triggered by hiPSCs. These results demonstrate that the use of MMC-treated hiPSCs and RPCs improves clinical and histological CKD parameters, avoided tumor formation, and therefore may be a promising cell therapy strategy for CKD.

Underweight Increases the Risk of End-Stage Renal Diseases for Type 2 Diabetes in Korean Population: Data From the National Health Insurance Service Health Checkups 2009-2017

OBJECTIVE

There is a controversy over the association between obesity and end-stage renal disease (ESRD) in people with or without type 2 diabetes; therefore, we examined the effect of BMI on the risk of ESRD according to glycemic status in the Korean population.

RESEARCH DESIGN AND METHODS

The study monitored 9,969,848 participants who underwent a National Health Insurance Service health checkup in 2009 from baseline to the date of diagnosis of ESRD during a follow-up period of ∼8.2 years. Obesity was categorized by World Health Organization recommendations for Asian populations, and glycemic status was categorized into the following five groups: normal, impaired fasting glucose (IFG), newly diagnosed diabetes, diabetes <5 years, and diabetes ≥5 years.

RESULTS

Underweight was associated with a higher risk of ESRD in all participants after adjustment for all covariates. In the groups with IFG, newly diagnosed type 2 diabetes, diabetes duration <5 years, and diabetes ≥5 years, the hazard ratio (HR) of the underweight group increased with worsening glycemic status (HR 1.431 for IFG, 2.114 for newly diagnosed diabetes, 4.351 for diabetes <5 years, and 6.397 for diabetes ≥5 years), using normal weight with normal fasting glucose as a reference. The adjusted HRs for ESRD were also the highest in the sustained underweight group regardless of the presence of type 2 diabetes (HR 1.606 for nondiabetes and 2.14 for diabetes).

CONCLUSIONS

Underweight showed more increased HR of ESRD according to glycemic status and diabetes duration in the Korean population. These associations also persisted in the group with sustained BMI during the study period.

Effect of caloric restriction on phosphate metabolism and uremic vascular calcification

Caloric restriction (CR) is known to have multiple beneficial effects on health and longevity. To study the effect of CR on phosphorus metabolism and vascular calcification (VC), rats were fed normal or restricted calories (67% of normal). The phosphorus content of the diets was adjusted to provide equal phosphorus intake independent of the calories ingested. After 50 days of CR, rats had negative phosphorus balance, lower plasma phosphorus, glucose, triglycerides, and leptin, and higher adiponectin than rats fed normal calories. Uremia was induced by 5/6 nephrectomy (Nx). After Nx, rats were treated with calcitriol (80 ng/kg ip every other day) and high-phosphorus diets (1.2% and 1.8%). No differences in aortic calcium content were observed between rats that ate normal or restricted calories before Nx in either rats that received 1.2% phosphorus (11.5 ± 1.7 vs. 10.9 ± 2.1 mg/g tissue) or in rats that received 1.8% phosphorus (12.5 ± 2.3 vs. 12.0 ± 2.9 mg/g of tissue). However, mortality was significantly increased in rats subjected to CR before Nx in both the 1.2% phosphorus groups (75% vs. 25%, P = 0.019) and 1.8% phosphorus groups (100% vs. 45%, P < 0.001). After calcitriol administration was stopped and phosphorus intake was normalized, VC regressed rapidly, but no significant differences in aortic calcium were detected between rats that ate normal or restricted calories during the regression phase (5.7 ± 2.7 and 5.2 ± 1.5 mg/g tissue). In conclusion, CR did not prevent or ameliorate VC and increased mortality in uremic rats.

Approaches to Obesity Management in Dialysis Settings: Renal Dietitian Perspectives

OBJECTIVES

Over 40% of individuals in the United States with end-stage kidney disease have obesity. Little is known about renal dietitian perspectives on obesity management in the setting of dialysis dependence.

DESIGN AND METHODS

An online 21-item survey was distributed to 118 renal dietitians via individual outreach and a professional organization e-mail listserv. Four themes were explored: the burden of obesity among dialysis patients, concepts of healthy weight loss, weight loss approaches, and challenges of obesity management in dialysis settings. Respondents were asked to rank approaches and biomarkers for obesity management from 0 (least important or not used) to 100 (most important). Free text fields were provided in each category for additional comments.

RESULTS

Thirty-one renal dietitians responded to the survey (26% response rate). The majority of respondents (90%) indicated that access to kidney transplantation was the main reason that dialysis patients with obesity desired weight loss. Calorie restriction was rated as the most common weight loss approach, and dry weight as the most important weight loss biomarker. Nearly 40% of respondents do not alter their nutritional approach when dialysis patients with obesity are losing weight, and 42% of respondents do not monitor changes in waist circumference. Exercise, diet counseling, and stress management were variably prioritized as weight loss management strategies. Barriers to obesity management in dialysis settings included lack of time, lack of training in weight loss counseling, and gaps in current renal nutritional guidelines.

CONCLUSION

Despite the high prevalence of obesity among individuals with end-stage kidney disease, the results of this survey suggest that current approaches to obesity management in dialysis settings are highly variable. Many renal dietitians lack time to counsel patients on healthy weight loss strategies. Nutritional guidelines are also needed to support people with dialysis dependence and obesity who desire or require weight loss.

The transition clinic in chronic kidney disease care

People with advanced chronic kidney disease and evidence of progression have a high risk of renal replacement therapy. Specialized transition clinics could offer a better option for preparing these patients for dialysis, transplantation or conservative care. This review focuses on the different aspects of such transition clinics. We discuss which patients should be referred to these units and when referral should take place. Patient involvement in the decision-making process is important and requires unbiased patient education. There are many themes, both patient-centred and within the healthcare structure, that will influence the process of shared decision-making and the modality choice. Aspects of placing an access for haemodialysis and peritoneal dialysis are reviewed. Finally, we discuss the importance of pre-emptive transplantation and a planned dialysis start, all with a focus on multidisciplinary collaboration at the transition clinic.

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.

Association Between Weight Loss Before Deceased Donor Kidney Transplantation and Posttransplantation Outcomes

RATIONALE & OBJECTIVE

There is debate on whether weight loss, a hallmark of frailty, signals higher risk for adverse outcomes among recipients of deceased donor kidney transplantation (DDKT).

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

Using national Organ Procurement and Transplantation Network data, we included all DDKT recipients in the United States between December 4, 2004, and December 3, 2014, who were adults (aged ≥ 18 years) when listed for DDKT.

EXPOSURES

Relative pre-DDKT weight change as a continuous predictor and categorized as <5% weight change from listing to DDKT, ≥5% to <10% weight loss, ≥10% weight loss, ≥5% to <10% weight gain, and ≥10% weight gain.

OUTCOMES

We examined 3 post-DDKT outcomes: (1) transplant hospitalization length of stay (LOS) in days, (2) all-cause graft failure, and (3) mortality.

ANALYTIC APPROACH

Unadjusted fractional polynomial methods, multivariable log-gamma models, and multivariable Cox proportional hazards models.

RESULTS

Among 94,465 recipients of DDKT, median pre-DDKT weight change was 0 (interquartile range, -3.5 to +3.9) kg. There were nonlinear unadjusted associations between relative pre-DDKT weight loss and longer transplant hospitalization LOS, higher all-cause graft loss, and higher mortality. Compared with recipients with <5% pre-DDKT weight change (n = 49,366; 52%), recipients who lost ≥10% of their listing weight (n = 10,614; 11%) had 0.66 (95% CI, 0.23-1.09) days longer average transplant hospitalization LOS (P = 0.003), 1.11-fold higher graft loss (adjusted HR [aHR], 1.11; 95% CI, 1.06-1.17; P < 0.001), and 1.18-fold higher mortality (aHR, 1.18; 95% CI, 1.11-1.25; P < 0.001) independent of recipient, donor, and transplant factors. Pre-DDKT dialysis exposure, listing body mass index category, and waiting time modified the association of pre-DDKT weight change with hospital LOS (interaction P < 0.10), but not with all-cause graft loss and mortality.

LIMITATIONS

Unmeasured confounders and inability to identify volitional weight change. Also, the higher significance level set to increase the power of detecting interactions with the fixed sample size may have resulted in increased risk for type 1 error.

CONCLUSIONS

DDKT recipients with ≥10% pre-DDKT weight loss are at increased risk for adverse outcomes and may benefit from augmented support post-DDKT.

Longitudinal Physical Activity Change During Hemodialysis and Its Association With Body Composition and Plasma BAIBA Levels

Rationale: Low physical activity is frequent in end stage renal disease. We evaluated the longitudinal change in physical activity and its barriers in hemodialysis (HD) patients and the association between the patterns of physical activity change, body composition, and beta-aminoisobutyric acid (BAIBA), as circulating myokine.

Methods: This is an observational study, where HD patients were considered in a 24-month follow-up. We assessed overtime the change of physical inactivity and its barriers by validated questionnaires, body composition by bioimpedance analysis, muscle strength by hand-dynamometer, and plasma BAIBA levels by liquid chromatography spectrometry. Parametric and non-parametric analyses were performed, as appropriate.

Results: Out of the 49 patients studied at baseline, 39 completed the first-year follow-up, and 29 completed the second year. At month 12, active patients had higher intracellular water (ICW) (P = 0.001) and cellular mass (P < 0.001), as well as at month 24 (P = 0.012, P = 0.002; respectively) with respect to inactive. A significant reduction in ICW was shown at month 12 (P = 0.011) and month 24 (P = 0.014) in all patients. The barrier “reduced walking ability” was more frequent in inactive patients with respect to active at month 12 (P = 0.003) and at month 24 (P = 0.05). At month 24, plasma BAIBA levels were higher among active patients with respect to inactive (P = 0.043) and a correlation was seen between muscle strength and ICW (r = 0.51, P = 0.005); normalizing BAIBA per body mass index, we found it lower with respect to baseline (P = 0.004), as well as after correcting per ICW (P = 0.001), as marker of muscle mass.

Conclusion: A high prevalence of physical inactivity persisted during a 24-month follow-up in this cohort. We found an association between physical activity and a decline in marker of muscularity and reduced plasma BAIBA levels.

Kidney cachexia or protein-energy wasting in chronic kidney disease: facts and numbers

BACKGROUND

Weight loss and homeostatic disturbances of both energy and protein balances are characteristics of several illnesses including cancer, heart failure, and chronic kidney disease (CKD). Different definitions have been used to describe this deleterious process. The term protein-energy wasting (PEW) has been proposed for CKD patients by the International Society of Renal Nutrition and Metabolism.

METHODS

We searched the publication in Medline from February 2008 to September 2018 using PEW or cachexia in their title.

RESULTS

Since its inception, the term PEW has been exceptionally successful, highlighted by 327 original publications referenced in PubMed over 10 years. Using this classification, several studies have confirmed that PEW is among the strongest predictors of mortality in CKD patients [hazard ratio of 3.03; confidence interval of 1.69-5.26 in 1068 haemodialysis patients and 1.40 (1.04-1.89) in 1487 non-dialysed patients across PEW stages 0 to 4]. Based on this classification, prevalence of PEW is 28% to 54% among 16 434 adults undergoing maintenance dialysis. PEW prevalence increases when renal function declines, that is, from <2% in CKD stages 1-2 to 11-54% in CKD stages 3-5. A more general definition of cachexia for all chronic diseases proposed by the Society on Sarcopenia, Cachexia and Wasting Disorders was also published concurrently. In the CKD area, we found 180 publications using 'cachexia' underlining that some confusion or overlap may exist. The definitions of PEW and cachexia are somewhat similar, and the main difference is that a loss of body weight >5% is a mandatory criterion for cachexia but supportive for PEW.

CONCLUSIONS

The recent understanding of cachexia physiopathology during CKD progression suggests that PEW and cachexia are closely related and that PEW corresponds the initial state of a continuous process that leads to cachexia, implicating the same metabolic pathways as in other chronic diseases. Despite the success of the definition of PEW, using a more uniform term such as 'kidney disease cachexia' could be more helpful to design future research through collaborative groups of researchers with focus on cachexia.

Effects of Variability in Blood Pressure, Glucose, and Cholesterol Concentrations, and Body Mass Index on End-Stage Renal Disease in the General Population of Korea

Aim: Metabolic parameters, such as blood pressure, glucose, lipid levels, and body weight, can interact with each other, and this clustering of metabolic risk factors is related to the progression to end-stage renal disease (ESRD). The effect of variability in metabolic parameters on the risk of ESRD has not been studied previously. Methods: Using nationally representative data from the Korean National Health Insurance System, 8,199,135 participants who had undergone three or more health examinations between 2005 and 2012 were included in this analysis. Intraindividual variability in systolic blood pressure (SBP), fasting blood glucose (FBG), total cholesterol (TC), and body mass index (BMI) was assessed by examining the coefficient of variation, variability independent of the mean, and average real variability. High variability was defined as the highest quartile of variability and low variability was defined as the lower three quartiles of variability. Results: Over a median (5–95%) of 7.1 (6.5–7.5) years of follow-up after the variability assessment period, 13,600 (1.7/1000 person-years) participants developed ESRD. For each metabolic parameter, an incrementally higher risk of ESRD was observed for higher variability quartiles compared with the lowest quartile. The risk of ESRD was 46% higher in the highest quartile of SBP variability, 47% higher in the highest quartile of FBG variability, 56% higher in the highest quartile of BMI variability, and 108% higher in the highest quartile of TC variability. Compared with the group with low variability for all four parameters, the group with high variability for all four parameters had a significantly higher risk for incident ESRD (hazard ratio (HR) 4.12; 95% CI 3.72–4.57). Conclusions: Variability in each metabolic parameter was an independent predictor of the development of ESRD among the general population. There was a composite effect of the variability in additional metabolic parameters on the risk of ESRD.

Precision Medicine for Nutritional Management in End-Stage Kidney Disease and Transition to Dialysis

Chronic kidney disease (CKD) is a global public health burden. Dialysis is not only costly but may not be readily available in developing countries. Even in highly developed nations, many patients may prefer to defer or avoid dialysis. Thus, alternative options to dialysis therapy or to complement dialysis are needed urgently and are important objectives in CKD management that could have huge clinical and economic implications globally. The role of nutritional therapy as a strategy to slow CKD progression and uremia was discussed as early as the late 19th and early 20th century, but was only seriously explored in the 1970s. There is a revival of interest recently owing to encouraging data as well as the increase of precision medicine with an emphasis on a personalized approach to CKD management. Although part of the explanation for the inconclusive data may relate to variations in study design and dietary prescription, diversity in genetic make-up, variations in the non-nutritional management of CKD, intra-individual variations in responses to dietary and nondietary treatment, psychosocial factors, and dietary compliance issues, these all may contribute to the heterogeneous data and responses. This brings in the evolving concept of precision medicine, in which disease management should be tailored and individualized according not only to clinical manifestations but also to the genetic make-up and biologic responses to therapy, which may vary depending on genetic composition. Precision nutrition management also should take into account patient demographics, social, psychological, education, and compliance factors, which all may influence the therapeutic needs and responses to the nutritional therapy prescribed. In this review, we provide a novel concept of precision medicine in nutritional management in end-stage kidney disease with a transition to dialysis and propose how this may be the way forward for nutritional therapy in the CKD population.

Energy-Dense Diets and Mineral Metabolism in the Context of Chronic Kidney Disease⁻Metabolic Bone Disease (CKD-MBD)

The aim of this paper is to review current knowledge about the interactions of energy-dense diets and mineral metabolism in the context of chronic kidney disease–metabolic bone disease (CKD-MBD). Energy dense-diets promote obesity and type II diabetes, two well-known causes of CKD. Conversely, these diets may help to prevent weight loss, which is associated with increased mortality in advanced CKD patients. Recent evidence indicates that, in addition to its nephrotoxic potential, energy-dense food promotes changes in mineral metabolism that are clearly detrimental in the context of CKD-MBD, such as phosphorus (P) retention, increased concentrations of fibroblast growth factor 23, decreased levels of renal klotho, and reduction in circulating concentrations of calcitriol. Moreover, in uremic animals, a high fat diet induces oxidative stress that potentiates high P-induced vascular calcification, and these extraskeletal calcifications can be ameliorated by oral supplementation of vitamin E. In conclusion, although energy-dense foods may have a role in preventing undernutrition and weight loss in a small section of the CKD population, in general, they should be discouraged in patients with renal disease, due to their impact on P load and oxidative stress.