Albumin Turnover in Peritoneal and Hemodialysis

Single-pool model urea clearance index is associated with sarcopenia and nutritional status in patients undergoing maintenance hemodialysis: a cross-sectional study

BACKGROUND

The single-pool model urea clearance index (single-pool Kt/Vurea; spKt/V) is the most commonly used method for dialysis adequacy assessment. However, only a few studies have examined the relationship between spKt/V values and parameters related to sarcopenia and nutritional status. This study aimed to evaluate whether the spKt/V is an indicator of sarcopenia and nutritional status in patients undergoing maintenance hemodialysis (MHD).

METHODS

A total of 142 patients were included in this single-center, cross-sectional study. Venous blood samples were collected shortly before the hemodialysis session. The adequacy of dialysis in patients receiving MHD was assessed using spKt/V. Sarcopenia was identified according to the Asian Working Group for Sarcopenia (2019) definition. Receiver operating characteristic curve and area under the curve were used to evaluate the predictive value of spKt/V in sarcopenia. Univariate and multivariate binary logistic regression analyses were used to determine the association between spKt/V and sarcopenia and nutritional status.

RESULTS

The mean spKt/V level was 1.3 ± 0.2, the prevalence of sarcopenia was 15.5% in patients on MHD. The best cutoff value of spKt/V in sarcopenia was 1.45 for both sexes, 1.33 and 1.45 for men and women, respectively (P < 0.05). The multivariate binary logistic regression shown that the spKt/V was independently positively associated with sarcopenia (OR = 122.88, 95% CI = 0.64-0.87, P = 0.002). Grouping spKt/V by the best cutoff value, when spKt/V ≥ 1.45, the OR of sarcopenia was 11.75 (95% CI = 3.16-43.67, P < 0.001). Subgroup analyses showed that when spKt/V ≥ 1.33 in men and spKt/V ≥ 1.45 in woman, the OR of sarcopenia was 9.73 (95% CI = 2.25-42.11, P = 0.002) and 14.52 (95% CI = 1.06-199.67, P = 0.045), respectively.

CONCLUSIONS

The present study showed that spKt/V was an important influencing factor of sarcopenia and malnutrition in Asian patients on MHD.

Experimental hemodialysis in diet-induced ketosis and the potential use of dialysis as an adjuvant cancer treatment

Numerous in vivo studies on the ketogenic diet, a diet that can induce metabolic conditions resembling those following extended starvation, demonstrate strong outcomes on cancer survival, particularly when combined with chemo-, radio- or immunological treatments. However, the therapeutic application of ketogenic diets requires strict dietary adherence from well-informed and motivated patients, and it has recently been proposed that hemodialysis might be utilized to boost ketosis and further destabilize the environment for cancer cells. Yet, plasma ketones may be lost in the dialysate-lowering blood ketone levels. Here we performed a single 180-min experimental hemodialysis (HD) session in six anesthetized Sprague-Dawley rats given ketogenic diet for five days. Median blood ketone levels pre-dialysis were 3.5 mmol/L (IQR 2.2 to 5.6) and 3.8 mmol/L (IQR 2.2 to 5.1) after 180 min HD, p = 0.54 (95% CI - 0.6 to 1.2). Plasma glucose levels were reduced by 36% (- 4.5 mmol/L), p < 0.05 (95% CI - 6.7 to - 2.5). Standard base excess was increased from - 3.5 mmol/L (IQR - 4 to - 2) to 0.5 mmol/L (IQR - 1 to 3), p < 0.01 (95% CI 2.0 to 5.0). A theoretical model was applied confirming that intra-dialytic glucose levels decrease, and ketone levels slightly increase since hepatic ketone production far exceeds dialytic removal. Our experimental data and in-silico modeling indicate that elevated blood ketone levels during ketosis are maintained during hemodialysis despite dialytic removal.

Association of Circulating Trimethylamine-N Oxide With Malnutrition and the Risk of Coronary Artery Disease in Patients With Maintenance Hemodialysis

OBJECTIVES

Malnutrition is a serious complication frequently observed in dialysis patients. Therefore, nutrition status evaluation and the early identification of malnutrition are clinically important. Trimethylamine N-oxide (TMAO) is reportedly associated with deteriorating metabolic profiles and cardiovascular diseases. The aim of our study was to investigate correlations between circulating TMAO levels and malnutrition and the risk of major adverse cardiovascular events in patients on maintenance hemodialysis.

METHODS

This retrospective observational study involved 228 subjects. Fasting plasma TMAO levels were detected using liquid chromatography-tandem mass spectrometry.

RESULTS

TMAO levels were significantly elevated in patients with malnutrition (8728.78 ± 704.12 ng/mL) when compared with those without (6532.1 ± 570.41 ng/mL, P < .01). TMAO levels were positively correlated with Subjective Global Assessment scores (ρ = 0.56, P = .02) and were independent risk factors for malnutrition after adjustment for multiple traditional risk factors (odds ratio = 2.07, 95% confidence interval: 1.41-3.62, P < .01). Furthermore, TMAO levels were good predictors of major adverse cardiovascular events in a 2-year follow-up period (area under the curve = 0.68, P < .01) and accuracy was increased to 74% when TMAO levels were combined with Subjective Global Assessment scores (area under the curve = 0.74, P = .02).

CONCLUSIONS

Elevated TMAO levels were independently associated with a risk of malnutrition and cardiovascular disease, and could be a useful predictive biomarker for risk stratification and cardiovascular disease management for patients on dialysis.

Predictive role of fluctuating biochemical parameters for mortality in hemodialysis patients

INTRODUCTION

High inflammation parameters like CRP and low albumin levels are considered as risk factors in CKD stage 5 patients. Due to dynamic changes in these parameters, there is evidence of an association between their variation and mortality in hemodialysis patients.

METHODS

We retrospectively analyzed 153 patients on chronic hemodialysis. Dialysis-specific biochemical parameters were measured at three-month intervals over a 42-month period. Fluctuations were calculated as the percentage change in two subsequent measurements.

RESULTS

Median age was 70 years. 41.10% of the patients died over the study period. Higher fluctuation rates in albumin and CRP were significantly associated with a higher mortality rate. Regression analysis revealed that only the fluctuations in albumin proved to be a predictive variable for the end point "death". If the fluctuation in albumin increases by 1%, the mortality risk rises by 22%.

CONCLUSION

Fluctuations in albumin are of predictive importance in patients on chronic hemodialysis.

Muscle Status Response to Oral Nutritional Supplementation in Hemodialysis Patients With Protein Energy Wasting: A Multi-Center Randomized, Open Label-Controlled Trial

Background: Muscle wasting, observed in patients with end-stage kidney disease and protein energy wasting (PEW), is associated with increased mortality for those on hemodialysis (HD). Oral nutritional supplementation (ONS) and nutrition counseling (NC) are treatment options for PEW but research targeting muscle status, as an outcome metric, is limited.

Aim: We compared the effects of combined treatment (ONS + NC) vs. NC alone on muscle status and nutritional parameters in HD patients with PEW.

Methods: This multi-center randomized, open label-controlled trial, registered under ClinicalTrials.gov (Identifier no. NCT04789031), recruited 56 HD patients identified with PEW using the International Society of Renal Nutrition and Metabolism criteria. Patients were randomly allocated to intervention (ONS + NC, n = 29) and control (NC, n = 27) groups. The ONS + NC received commercial renal-specific ONS providing 475 kcal and 21.7 g of protein daily for 6 months. Both groups also received standard NC during the study period. Differences in quadriceps muscle status assessed using ultrasound (US) imaging, arm muscle area and circumference, bio-impedance spectroscopy (BIS), and handgrip strength (HGS) methods were analyzed using the generalized linear model for repeated measures.

Results: Muscle indices as per US metrics indicated significance (p < 0.001) for group × time interaction only in the ONS + NC group, with increases by 8.3 and 7.7% for quadriceps muscle thickness and 4.5% for cross-sectional area (all p < 0.05). This effect was not observed for arm muscle area and circumference, BIS metrics and HGS in both the groups. ONS + NC compared to NC demonstrated increased dry weight (p = 0.039), mid-thigh girth (p = 0.004), serum prealbumin (p = 0.005), normalized protein catabolic rate (p = 0.025), and dietary intakes (p < 0.001), along with lower malnutrition–inflammation score (MIS) (p = 0.041). At the end of the study, lesser patients in the ONS + NC group were diagnosed with PEW (24.1%, p = 0.008) as they had achieved dietary adequacy with ONS provision.

Conclusion: Combination of ONS with NC was effective in treating PEW and contributed to a gain in the muscle status as assessed by the US, suggesting that the treatment for PEW requires nutritional optimization via ONS.

Potential relationship between eGFRcystatin C /eGFRcreatinine -ratio and glomerular basement membrane thickness in diabetic kidney disease

Diabetic kidney disease (DKD) is a leading cause of end-stage renal disease and renal replacement therapy worldwide. A pathophysiological hallmark of DKD is glomerular basal membrane (GBM) thickening, whereas this feature is absent in minimal change disease (MCD). According to fundamental transport physiological principles, a thicker GBM will impede the diffusion of middle-molecules such as cystatin C, potentially leading to a lower estimated GFR (eGFR) from cystatin C compared to that of creatinine. Here we test the hypothesis that thickening of the glomerular filter leads to an increased diffusion length, and lower clearance, of cystatin C. Twenty-nine patients with a kidney biopsy diagnosis of either DKD (n = 17) or MCD (n = 12) were retrospectively included in the study. GBM thickness was measured at 20 separate locations in the biopsy specimen and plasma levels of cystatin C and creatinine were retrieved from health records. A modified two-pore model was used to simulate the effects of a thicker GBM on glomerular water and solute transport. The mean age of the patients was 52 years, and 38% were women. The mean eGFRcystatin C /eGFRcreatinine -ratio was 74% in DKD compared to 98% in MCD (p < 0.001). Average GBM thickness was strongly inversely correlated to the eGFRcystatin C /eGFRcreatinine -ratio (Pearson's r = -0.61, p < 0.01). Two-pore modeling predicted a eGFRcystatin C /eGFRcreatinine -ratio of 78% in DKD. We provide clinical and theoretical evidence suggesting that thickening of the glomerular filter, increasing the diffusion length of cystatin C, lowers the eGFRcystatin C /eGFRcreatinine -ratio in DKD.

Understanding Development of Malnutrition in Hemodialysis Patients: A Narrative Review

Hemodialysis (HD) majorly represents the global treatment option for patients with chronic kidney disease stage 5, and, despite advances in dialysis technology, these patients face a high risk of morbidity and mortality from malnutrition. We aimed to provide a novel view that malnutrition susceptibility in the global HD community is either or both of iatrogenic and of non-iatrogenic origins. This categorization of malnutrition origin clearly describes the role of each factor in contributing to malnutrition. Low dialysis adequacy resulting in uremia and metabolic acidosis and dialysis membranes and techniques, which incur greater amino-acid losses, are identified modifiable iatrogenic factors of malnutrition. Dietary inadequacy as per suboptimal energy and protein intakes due to poor appetite status, low diet quality, high diet monotony index, and/or psychosocial and financial barriers are modifiable non-iatrogenic factors implicated in malnutrition in these patients. These factors should be included in a comprehensive nutritional assessment for malnutrition risk. Leveraging the point of origin of malnutrition in dialysis patients is crucial for healthcare practitioners to enable personalized patient care, as well as determine country-specific malnutrition treatment strategies.

Intravascular albumin loss is strongly associated with plasma volume withdrawal in dialysis patients

INTRODUCTION

Low circulating albumin closely predicts mortality in end-stage renal disease (ESRD) patients. The cause(s) of hypoalbuminemia (hALB) in ESRD patients remains to be elucidated. The aim of the present study was to determine the role of plasma volume (PV) withdrawal in the reduction of total circulating albumin and essential blood solutes induced by hemodialysis (HD).

METHODS

PV determined with high-precision automated carbon monoxide-rebreathing, total circulating as well as concentration of plasma albumin and electrolytes were assessed prior to and after 4-hour HD in 10 ESRD patients.

FINDINGS

Baseline PV ranged from 3.5 to 6.2 l. After HD, PV was decreased by 689 ± 566 mL (-16%) (P = 0.004). Total circulating albumin was largely reduced after HD (170.8 ± 35.1 vs. 146.1 ± 48.9 g, P = 0.008), while albumin concentration was unaltered. According to a strong linear relationship (r = 0.91, P < 0.001), one-third of total circulating albumin is lost from the intravascular compartment for every liter of PV removed. Similar results were found regarding Na⁺ and Ca²⁺ electrolytes.

DISCUSSION

Total circulating albumin, but not albumin concentration, is substantially reduced by HD in proportion to the amount of PV removed from the circulation. This study highlights the potential contributing role of PV withdrawal to hALB in ESRD patients.

Optimized vs. Standard Automated Peritoneal Dialysis Regimens (OptiStAR): study protocol for a randomized controlled crossover trial

Background

It has been estimated that automated peritoneal dialysis (APD) is currently the fastest growing renal replacement therapy in the world. However, in light of the growing number of diabetic patients on peritoneal dialysis (PD), the unwanted glucose absorption during APD remains problematic. Recent results, using an extended 3-pore model of APD, indicated that large reductions in glucose absorption are possible by using optimized bi-modal treatment regimens, having “UF cycles” using a higher glucose concentration, and “Clearance cycles” using a low concentration or, preferentially, no glucose. The present study is designed to test the theoretical prediction of a lower glucose absorption using these novel regimes.

Methods

This study is a randomized single-center, open-label, prospective study. Prevalent PD patients between 18 and 75 years old without known catheter problems or recent peritonitis are eligible for inclusion. Patients are allocated to a first treatment session of either standard APD (6 × 2 L 1.36% over 9 h) or optimized APD (7 × 2 L 2.27% + 5 × 2 L 0.1% over 8 h). A second treatment session using the other treatment will be performed in a crossover fashion. Samples of the dialysis fluid will be taken before and after the treatment, and the volume of the dialysate before and after the treatment will be carefully assessed. The primary endpoint is difference in glucose absorption between the optimized and standard treatment. Secondary endpoints are ultrafiltration, sodium removal, Kt/V urea, and Kt/V Creatinine. The study will be closed when a total of 20 patients have successfully completed the interventions or terminated according to interim analysis. A Monte Carlo power analysis shows that the study has 80% power to detect a difference of 10 g (in line with that of theoretical results) in glucose absorption between the two treatments in 10 patients.

Discussion

The present study is the first clinical investigation of optimized bi-modal treatments proposed by recent theoretical studies.

Trial registration

ClinicalTrials.gov identifier: NCT04017572. Registration date: July 12, 2019, retrospectively registered.

Fushen Granule, A Traditional Chinese Medicine, ameliorates intestinal mucosal dysfunction in peritoneal dialysis rat model by regulating p38MAPK signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Fushen Granule (FSG) is a Chinese medicinal formular prepared in hospital to treat intestinal mucosal dysfunction induced by peritoneal dialysis (PD). However, the mechanisms of this formular has not been studied yet.

AIM OF THE STUDY

The present study was designed to investigate the effect of FSG against intestinal dysfunction during PD treatment and explore the potential mechanisms using a rat PD model.

METHODS AND METHODS

In the present study, the effect of FSG on improving intestinal mucosal architecture injury was intuitively shown by hematoxylin-eosin staining, the serum levels of DAO and D-lactate were measured to evaluate the intestinal permeability by the DAO Assay Kit and D-Lactic Acid ELISA Kit. The expression of the intestinal mucosal barrier related inflammation factor by real-time PCR. The main effective constituents of FSG were characterized by UPLC/Q-TOF analysis, and the targets and pathways of the constituents were predicted via TCMSP database and IPA. the activation of p38MAPK signaling pathway by western blotting.

RESULTS

HE staining results showed that FSG protected against intestinal mucosal injury in pathology in PD rats. FSG decreased the intestinal mucosal permeability by increasing the transepithelial electrical resistance (TER) level and decreasing the intestinal clearance of fluorescein-isothiocyanate dextran (FD4) and the level of D-lactate and diamine oxidase (DAO). FSG significantly decreased the expression of ICAM-1, IL-1β, iNOS and TNF-α, and further inhibited the activation of p38MAPK signaling pathway via down-regulating the expression of P-p38MAPK and up-regulating the expression of DUSP1, occludin, and ZO-1.

CONCLUSION

This study demonstrates that FSG ameliorated intestinal mucosal dysfunction in PD by decreasing expression of pro-inflammatory cytokines and inhibiting the activation of p38MAPK signaling pathway. The results provide a promising basis for the alternative medicine treatment of intestinal mucosal dysfunction in PD.

Changes in serum albumin concentrations during transition to dialysis and subsequent risk of peritonitis after peritoneal dialysis initiation: a retrospective cohort study

BACKGROUND

Evidence shows that lower serum albumin concentrations are associated with the risk of peritoneal dialysis (PD)-related peritonitis. However, little is known regarding its relationship and magnitude of change before PD initiation and peritonitis risk.

METHODS

We performed a multicenter retrospective cohort study on 1169 adult cases of PD in Thailand. The associations of serum albumin at concentration (< 2.5, 2.5-3.5, > 3.5 [reference] g/dL) and changes (unchanged + 0.1 to - 0.1 [reference], decrease or increase > 0.1 g/dL) over 3- and 6-month before PD initiation with PD-related peritonitis were examined. Time-to-first and longitudinal rates of peritonitis were examined using the multivariable Cox proportional hazards model and Poisson regression analyses, respectively.

RESULTS

At baseline PD initiation, patients with serum albumin concentration < 2.5 and 2.5-3.5 g/dL had an adjusted hazard ratio (HR) of 1.69 and 2.0 times higher peritonitis (vs. > 3.5 g/dL), respectively. Compared to the unchanged group, patients with a decrease and increase in serum albumin concentrations during transitioning to dialysis were significantly associated with higher and lower risk of peritonitis, adjusted HR of 2.25 (95% confidence interval [CI] 1.85-2.75) and 0.53 (95% CI 0.42-0.68) over three-month, and 1.43 (95% CI 1.15-1.79) and 0.64 (95% CI 0.52-0.79) over six-month, respectively. Similar trends of longitudinal rates of serum albumin concentrations and peritonitis risk were observed.

CONCLUSIONS

Serum albumin concentrations at PD initiation and its magnitude of change during the transition to dialysis are strongly associated with subsequent risk of peritonitis. Further studies are required on strategies modifying serum albumin concentration during the transition to PD.

Serum albumin and mortality in patients with HIV and end-stage renal failure on peritoneal dialysis

Background

Peritoneal dialysis (PD) is an easily implementable dialysis modality in end-stage renal disease (ESRD). PD may improve access to renal replacement therapy in low- and middle-income countries; however, these countries have a higher prevalence of protein-energy wasting in patients and poorer socioeconomic conditions. We evaluated the effects of HIV infection on serum albumin levels in ESRD patients starting continuous ambulatory PD (CAPD) and mortality outcomes.

Methods

We conducted a single-center prospective cohort study of consecutive incident CAPD patients recruited from two hospitals in Durban, South Africa, from September 2012 to February 2015. Seventy HIV-negative and 70 HIV-positive ESRD patients were followed monthly for serum albumin levels and mortality events during the first 18 months of CAPD therapy.

Results

The HIV-positive cohort recorded 28 deaths (40%) among patients with a functional CAPD catheter at 18 months and 13 deaths (18.6%) in the HIV-negative cohort (p = 0.005). The mean serum albumin levels were lower in the HIV-positive cohort than in the HIV-negative cohort during the 18-month follow-up. The mean difference in serum albumin levels between the two cohorts was 4.24 g/L (95% confidence interval [CI] 2.02–6.46, p<0.001) at baseline and 3.99 g/L (95% CI 1.19–6.79, p = 0.006) at 18 months. HIV-positive status (adjusted regression coefficient -2.84, CI -5.00–-0.67, p = 0.011), diabetes (adjusted coefficient -2.85; CI, -5.58–-0.12; p = 0.041), and serum C-reactive protein and blood hemoglobin levels were independent predictors of serum albumin levels on multivariable linear regression. Baseline serum albumin <25 g/L (subdistribution-hazard ratio [SHR] 13.06, 95% CI 3.09–55.14, p<0.001) and CD4⁺ cell count <200 cells/μL (SHR 3.2, CI 1.38–7.45, p = 0.007) were independent predictors of mortality in our competing risk model.

Conclusions

HIV infection can adversely affect serum albumin levels in ESRD patients managed with CAPD, while low baseline serum albumin levels and impaired immunity reliably predict mortality.

Sustained, delayed, and small increments in glomerular permeability to macromolecules during systemic ET-1 infusion mediated via the ETA receptor

Emerging evidence indicates that endogenous production of endothelin (ET)-1, a 21-amino acid peptide vasoconstrictor, plays an important role in proteinuric kidney disease. Previous studies in rats have shown that chronic administration of ET-1 leads to increased glomerular albumin leakage. The underlying mechanisms are, however, currently not known. Here, we used size-exclusion chromatography to measure glomerular sieving coefficients for neutral FITC-Ficoll (molecular Stokes-Einstein radius: 15-80 Å, molecular weight: 70 kDa/400 kDa) in anesthetized male Sprague-Dawley rats (n = 12) at baseline and at 5, 15, 30, and 60 min after intravenous administration of ET-1. In separate experiments, ET-1 was given together with the selective ET type A (ET_A) or ET type B (ET_B) receptor antagonists JKC-301 and BQ-788, respectively. At both 15 and 30 min postadministration, the glomerular sieving coefficient for macromolecular Ficoll (70 Å) was significantly increased to 4.4 × 10^-5 ± 0.7 × 10^-5 (P = 0.024) and 4.5 × 10^-5 ± 0.8 × 10^-5 (P = 0.007), respectively, compared with baseline (2.2 × 10^-5 ± 0.4 ×10^-5). Decreased urine production after ET-1 prevented the use of higher doses of ET-1. Data analysis using the two-pore model indicated changes in large-pore permeability after ET-1, with no changes in the small-pore pathway. Administration of ET_A blocker abrogated the permeability changes induced by ET-1 at 30 min, whereas blockade of ET_B receptors was ineffective. Mean arterial pressure was only significantly increased at 60 min, being 123 ± 4 mmHg compared with 111 ± 2 mmHg at baseline (P = 0.02). We conclude that ET-1 evoked small, delayed, and sustained increases in glomerular permeability, mediated via the ET_A receptor.

Computer Simulations of Continuous Flow Peritoneal Dialysis Using the 3-Pore Model-A First Experience

Background:Continuous flow peritoneal dialysis (CFPD) is performed using a continuous flux of dialysis fluid via double or dual-lumen PD catheters, allowing a higher dialysate flow rate (DFR) than conventional treatments. While small clinical studies have revealed greatly improved clearances using CFPD, the inability to predict ultrafiltration (UF) may confer a risk of potentially harmful overfill. Here we performed physiological studies of CFPD in silico using the extended 3-pore model.Method:A 9-h CFPD session was simulated for: slow (dialysate to plasma creatinine [D/P crea] < 0.6), fast (D/P crea > 0.8) and average (0.6 ≤ D/P crea ≤ 0.8) transporters using 1.36%, 2.27%, or 3.86% glucose solutions. To avoid overfill, we applied a practical equation, based on the principle of mass-balance, to predict the UF rate during CFPD treatment.Results:Increasing DFR > 100 mL/min evoked substantial increments in small- and middle-molecule clearances, being 2 - 5 times higher compared with a 4-h continuous ambulatory PD (CAPD) exchange, with improvements typically being smaller for average and slow transporters. Improved UF rates, exceeding 10 mL/min, were achieved for all transport types. The β₂-microglobulin clearance was strongly dependent on the UF rate and increased between 60% and 130% as a function of DFR. Lastly, we tested novel intermittent-continuous regimes as an alternative strategy to prevent overfill, being effective for 1.36% and 2.27%, but not for 3.86% glucose.Conclusion:While we find substantial increments in solute and water clearance with CFPD, previous studies have shown similar improvements using high-volume tidal automated PD (APD). Lastly, the current in silico results need confirmation by studies in vivo.

Hemodialysis access type is associated with blood pressure variability and echocardiographic changes in end-stage renal disease patients

Arteriovenous fistula (AVF) strategy has been recommended in clinical guidelines for a long time due to the survival benefits associated with it. However, the underlying mechanism still needs to be explored. This retrospective cohort study included 611 patients who received hemodialysis in West China Hospital Medical Center between January 1, 2014 and December 31, 2014. Patient characteristics, dialysis parameters, and 1-year blood pressure records were collected at baseline. Echocardiographic changes and clinical outcomes were assessed during the 59-month follow-up. Our study showed that fistulas were associated with lower long-term systolic blood pressure (SBP) standard deviation (SD) (P < 0.0001), lower long-term SBP residual metric (P < 0.0001), and lower intradialytic SBP residual (P = 0.001). Fistulas were also associated with a higher but non-significant proportion of the newly developed left ventricular (LV) hypertrophy (8.29% vs. 6.78%, P = 0.116) and increased LV volume (8.29% vs. 4.52%, P = 0.139), as well as a lower proportion of the newly developed left ventricular ejection fraction (LVEF) dysfunction (1.62% vs. 2.82%, P = 0.586). After a median of 59-month follow-up, catheter group showed a higher risk of cardiovascular events (hazard ratio [HR] 1.21; 95% confidence interval [95%CI] 1.01-1.52), all-cause infection (HR 1.25; 95%CI 1.07-1.47), and access-related infection (HR 2.88; 95%CI 1.76-4.68). However, the advantage of fistulas only retained in low-albumin subgroup (serum albumin < 40 g/l) except for access-related infections. Our results suggested the possible attribution of BPV and other patient factors to fistula-associated survival benefits.

Differences in Dialysis Efficacy Have Limited Effects on Protein-Bound Uremic Toxins Plasma Levels over Time

The protein-bound uremic toxins para-cresyl sulfate (pCS) and indoxyl sulfate (IS) are associated with cardiovascular disease in chronic renal failure, but the effect of different dialysis procedures on their plasma levels over time is poorly studied. The present prospective, randomized, cross-over trial tested dialysis efficacy and monitored pre-treatment pCS and IS concentrations in 15 patients on low-flux and high-flux hemodialysis and high-convective volume postdilution hemodiafiltration over six weeks each. Although hemodiafiltration achieved by far the highest toxin removal, only the mean total IS level was decreased at week three (16.6 ± 12.1 mg/L) compared to baseline (18.9 ± 13.0 mg/L, p = 0.027) and to low-flux dialysis (20.0 ± 12.7 mg/L, p = 0.021). At week six, the total IS concentration in hemodiafiltration reached the initial values again. Concentrations of free IS and free and total pCS remained unaltered. Highest beta₂-microglobulin elimination in hemodiafiltration (p < 0.001) led to a persistent decrease of the plasma levels at week three and six (each p < 0.001). In contrast, absent removal in low-flux dialysis resulted in rising beta₂-microglobulin concentrations (p < 0.001). In conclusion, this trial demonstrated that even large differences in instantaneous protein-bound toxin removal by current extracorporeal dialysis techniques may have only limited impact on IS and pCS plasma levels in the longer term.

Clinical Significance of Phase Angle in Non-Dialysis CKD Stage 5 and Peritoneal Dialysis Patients

Background: Fluid overload and protein-energy wasting (PEW) are common in patients with end-stage renal disease (ESRD) and lead to a poor prognosis. We aimed to evaluate the volume and nutritional status of ESRD patients and to determine the clinical significance of phase angle (PhA). Methods: This study was a cross-sectional comparison of bioimpedance spectroscopy (BIS) findings in patients with non-dialysis chronic kidney disease (CKD) stage 5 (CKD5-ND, N = 80) and age/sex-matched peritoneal dialysis patients (PD, N = 80). PEW was defined as a PhA less than 4.5°. Results: The PhA was found to be positively associated with a geriatric nutritional risk index (GNRI, r = 0.561, p < 0.001), lean tissue index (LTI, r = 0.473, p < 0.001), and albumin (r = 0.565, p < 0.001) while OH/ECW (r = −0.824, p < 0.001) showed an inverse correlation. The CKD5-ND group had more overhydration (p = 0.027). The PD group had significantly higher PhA (p = 0.023), GNRI (p = 0.005), hemoglobin (p < 0.001), and albumin (p = 0.003) than the CKD5-ND group. The cut-off values predicting PEW were found to be 3.55 g/dL for albumin, 94.9 for GNRI, and 12.95 kg/m² for LTI in PD patients. Conclusions: This study demonstrated that PhA could be used as a marker to reflect nutritional status in patients with ESRD. Since BIS can inform both volume and nutritional status, regular monitoring will provide the basis for active correction of fluid overload and nutritional supplementation, which may improve outcomes in patients with ESRD.

The Diet and Haemodialysis Dyad: Three Eras, Four Open Questions and Four Paradoxes. A Narrative Review, Towards a Personalized, Patient-Centered Approach

The history of dialysis and diet can be viewed as a series of battles waged against potential threats to patients' lives. In the early years of dialysis, potassium was identified as "the killer", and the lists patients were given of forbidden foods included most plant-derived nourishment. As soon as dialysis became more efficient and survival increased, hyperphosphatemia, was identified as the enemy, generating an even longer list of banned aliments. Conversely, the "third era" finds us combating protein-energy wasting. This review discusses four questions and four paradoxes, regarding the diet-dialysis dyad: are the "magic numbers" of nutritional requirements (calories: 30-35 kcal/kg; proteins > 1.2 g/kg) still valid? Are the guidelines based on the metabolic needs of patients on "conventional" thrice-weekly bicarbonate dialysis applicable to different dialysis schedules, including daily dialysis or haemodiafiltration? The quantity of phosphate and potassium contained in processed and preserved foods may be significantly different from those in untreated foods: what are we eating? Is malnutrition one condition or a combination of conditions? The paradoxes: obesity is associated with higher survival in dialysis, losing weight is associated with mortality, but high BMI is a contraindication for kidney transplantation; it is difficult to limit phosphate intake when a patient is on a high-protein diet, such as the ones usually prescribed on dialysis; low serum albumin is associated with low dialysis efficiency and reduced survival, but on haemodiafiltration, high efficiency is coupled with albumin losses; banning plant derived food may limit consumption of "vascular healthy" food in a vulnerable population. Tailored approaches and agreed practices are needed so that we can identify attainable goals and pursue them in our fragile haemodialysis populations.