The urea reduction ratio and serum albumin concentration as predictors of mortality in patients undergoing hemodialysis

Pregnancy in Chronic Dialysis: A Review and Analysis of the Literature

Pregnancy is uncommon in end-stage renal failure, particularly in patients requiring dialysis. We reviewed the literature from 1965 to date, seeking an optimal way of dialyzing pregnant women after encountering one such patient.

Methods

We searched the English literature by cross-referencing “pregnancy” with “hemo-” or “peritoneal dialysis” and “renal failure”. Eighty-six pregnancies worldwide were found to which we added one case of our own. Various independent factors were studied against gestational age at delivery using uni- and multivariate analysis. These factors included mother's age, previous delivery, diagnoses of renal disease, dialysis duration prior to pregnancy, gestational age at onset of dialysis, dialysis type, level of hemoglobin during pregnancy, BUN and creatinine targets, BUN/creatinine ratio, dialysis intensity at the beginning and end of pregnancy, influence of erythropoietin and dialysis complications.

Results

Of the 87 pregnancies, 12% resulted in stillbirths, 9% of neonates died prior to discharge. The mean gestational age at delivery was 32 ± 5 weeks, and the mean birth weight 1604 ± 652 g. Two congenital abnormalities and one twin pregnancy were reported. 48% of deliveries were premature. Pre-eclampsia was reported in 11%, and worsening hypertension in 17%. CAPD was used in 25 and hemodialysis in 62 patients. Fetal survival was similar in both cases (72% vs 82%), although incidence of various dialysis complications differed. The conventional dialysis goals of a low target BUN level and hemoglobin for pregnant patients were not factors in predicting fetal outcome. The number of hemodialyses/week were negatively correlated (R = -0.35, P = 0.061), but the hours of dialysis positively correlated (R = 0.42, p = 0.035) to gestational age. Fetal survival was independently influenced by creatinine level [564 µmol/L when baby survived vs 788 µmol/L when baby died (p = 0.021)], BUN/creatinine ratio (50 vs 30, p = 0.053), and hours of dialysis (5.6 hrs vs 3.6 hrs, p=0.013). There was no relation of either frequency or volume of peritoneal dialysis exchanges to gestational age or fetal survival.

Conclusions

Greater attention to a high intake of protein (>1.5 g/kg) and higher dose of hemodialysis, achieved by longer, every other day dialysis, may be the optimal approach to pregnant patients on hemodialysis. Our first attempt to define the goal of hemodialysis is to keep the predialysis creatinine below 600 mmol/L and the protein intake high enough so the predialysis BUN level is >25 mmol/L. There are no clear guidelines on how to best perform CAPD.

Mass Balance Index: An Index for Adequacy of Dialysis and Nutrition

Determining adequacy of dialysis has remained a problem for the nephrologist despite the results of the National Cooperative Dialysis Study published more than 20 years ago. Urea Kinetics Modelling (UKM) which requires computer data entry is time-consuming for the dialysis staff but is the only method that has been rigorously studied. Furthermore, it is unclear today what value of Kt/V represents ideal dialysis; the technique is subject to a number of errors associated with estimation of dialyser clearance (K) and volume of distribution of urea (V) but it is useful for calculating protein catabolic rate (PCR). Methods that use urea reduction ratios (URR) is widely used because it is simpler but not always accurate and suffer from an inability to calculate PCR. Direct dialysis quantification (DDQ) can overcome a number of these problems but it is too cumbersome for routine use. Simpler methods to determine dialysateside kinetics have the advantage of solving a number of these problems and also facilitate the calculation of PCR to determine the patient's nutritional state. In our study, we have demonstrated that by taking two dialysate samples at the beginning and at the end of dialysis (2-DSM), it is possible to determine total urea removal (TUR) which is equivalent to DDQ. By taking blood samples after dialysis and before the next dialysis, it is possible to calculate the total urea generated (TUG). The ratio of TUR/TUG will provide an index of dialysis which places emphasis on removal of solute that has accumulated in the inter-dialytic interval thus re-establishing a state of equilibrium. We refer to this index as the Mass Balance Index (MBI). The MBI is also useful in helping to identify those patients whose PCR is inadequate since the mean MBI for patients with an nPCR <0.8 was 0.93 ± 0.03 vs 1.08 ± 0.02 in those with a PCR >0.8. In these two groups of patients the Kt/V was not significantly different, 1.49 ± 0.07 vs 1.53 ± 0.06, p -0.64. We suggest that the emphasis for adequacy of dialysis should shift away from Kt/V to maintaining a state of equilibrium by removing the solutes that accumulate between dialysis and by identifying those patients with an inadequate PCR.

Factors Affecting Npcr in Hemodialysed Patients

The determination of dialysis adequacy is difficult and definitions are in a state of flux (Lindsay). In fact, after fifteen years from the introduction of urea kinetics into clinical practice, nephrologists still do not agree on recognizing the real utility of it. Gotch and Sargent in their mechanistic analysis of the NCDS indicated that the dose of small molecules removal could be defined by Kt/V urea. The results of the NCDS were depicted in a three-variable plot in which six domains could be seen. Several reports have documented malnutrition as being frequently present in patients on maintenance hemodialysis. It is generally accepted that a suboptimal nutritional status is associated with an increased morbidity and may adversely affect rehabilitation and the quality of life. In 1989 Lindsay et al showed that low levels of Kt/V corresponded with low levels of nPCR and found a direct correlation between the two parameters. On this basis, they suggested the hypothesis of nPCR dependence on Kt/V. The Authors showed a good correlation (r=0.73) between nPCR and Kt/V in 55 patients. This work aims to evaluate the correlation between Kt/V and nPCR, real age and dialytic age in a dialytic population in Southern Italy, during a long period of observation (six years, follow up 2,692 months). One hundred and thirty-four patients were studied in six years of observation. Follow up: 2692 months. Twenty-six patients died during the observation period. The simple regression analysis of nPCR vs. Kt/V, real age and dialytic age was performed in 63 anuric patients. nPCR showed a statistical difference (p<0.01) versus reall age, but no difference versus dialytic age and Kt/V. Our research data show that increasing Kt/V administration does not modify the nPCR of patients with initial and steady low protein intake over a medium time of observation. The same happens in patients with initial and steady high protein intake, when decreasing Kt/V administration in a short period of observation. We confirm that nPCR and Kt/V do not show any mathematical correlation in short and medium times of observation. It is also stressed by the simple regression analysis of data for a selected population of anuric uremics on dialysis thrice weekly for long observation times (between three and six years). Variance analysis (in 8 patients who had used all the membranes) showed differences between Kt/V and dialytic age, but not nPCR and real age. Kt/V and biocompatibility do not appear to be correlated directly with nPCR, because other factors are important in determining the general well-being in uremic patients. Such factors have to be considered when prescribing the dialytic “dose” and in clinically evaluating a uremic patient.

Individual differences in biocompatibility responses to hemodialysis

There are very few reports in the literature on individual differences in the response to dialysis treatment. We studied the influence of the individual patient, dialysis membrane quality, blood-flow (Qb) and surface area on leukocyte activation and complement generation (C3a) during 234 hemodialysis treatments using Cuprophan (CU), hemophane (HE) and polyamide (PA) dialyzers. The most common reaction was a decrease in leukocyte count and an increase in C3a after 15 minutes of treatment. Leukocyte overshoot by the end of dialysis was observed at high Qb for all three membranes but at low Qb only during CU treatments. The reaction patterns were influenced by the quality of the membrane, area and Qb. Analysis of each individual patient showed for a large number of treatments reaction patterns corresponding to those described in the literature. However, some patients reacted differently. In four patients (20%), the nadir in leukocyte count and maximum in C3a concentration was reached considerably later during CU-dialysis. Three patients were devoid of pronounced early leukocyte response but presented with the late overshoot during CU-dialysis. Three other patients reacted with an early drop in leukocyte count and a rapid increase in C3a generation during PA treatments but not during HE treatments. Three other patients reacted vice versa. A particular mode of dialysis treatment may thus be biocompatible for some patients but not necessarily for all. In the case biocompatibility is desired the individual response to the particular dialysis mode needs to be identified. The underlying mechanisms warrant further studies.

Protein Carbamylation in Peritoneal Dialysis and the Effect of Low Glucose Plus Amino Acid Solutions

Protein carbamylation is a post-translational urea-driven protein modification associated with mortality. Free amino acids (AAs) competitively inhibit protein carbamylation and parenteral AA therapy reduces carbamylation in hemodialysis (HD) patients. Peritoneal dialysis (PD) yields differences in urea clearance and AA balance compared with HD, but the influence of PD and intraperitoneal AA solutions on carbamylation is unclear. Thus, we first measured carbamylated albumin (C-Alb; a marker of carbamylation load) in 100 diabetic HD patients frequency-matched by age, sex, and race to 98 diabetic PD subjects from the IMPENDIA trial, which originally compared the metabolic effects of low-glucose PD solutions (incorporating icodextrin and AAs) to a control group (dextrose-only solutions). We then determined the effects of the AA-enriched PD solutions by measuring the 6-month change in C-Alb within the IMPENDIA cohort by treatment allocation (48 treated vs 50 controls). Peritoneal dialysis patients, when compared with HD patients, had higher baseline urea and higher C-Alb. Among IMPENDIA participants, there was no difference in C-Alb change in either arm, but treated subjects showed a trend towards increased carbamylation. Treated subjects also demonstrated an increase in urea, possibly explaining the carbamylation trend. In summary, carbamylation levels in PD patients appeared higher than in matched HD patients. A regimen of AA and low-glucose PD solutions did not reduce C-Alb in IMPENDIA subjects.

Prognostic Impact of Serum Albumin Concentration for Neurologically Favorable Outcome in Patients Treated with Targeted Temperature Management After Out-of-Hospital Cardiac Arrest: A Multicenter Prospective Study

To assess whether serum albumin concentration measured upon hospital arrival was useful as an early prognostic biomarker for neurologically favorable outcome in out-of-hospital cardiac arrest (OHCA) patients treated with target temperature management (TTM). This prospective, multicenter observational study (The CRITICAL Study) carried out between July 1, 2012 and December 31, 2014 in Osaka Prefecture, Japan involving 13 critical care medical centers (CCMCs) and one non-CCMC with an emergency department. This study included patients ≥18 years of age who underwent an OHCA, for whom resuscitation was attempted by Emergency Medical Services personnel and were then transported to participating institutions, and who were then treated with TTM. Based on the serum albumin concentration upon hospital arrival, involved patients were divided into four quartiles (Q1-Q4) defined as Q1 (<3.0 g/dL), Q2 (≥3.0, <3.4 g/dL), Q3 (≥3.4, <3.8 g/dL), and Q4 (≥3.8 g/dL). The primary outcome of this study was 1-month survival with neurologically favorable outcome defined by cerebral performance category 1 or 2. During the study period, a total of 327 were eligible for our analysis. The overall proportion of neurologically favorable outcome was 33.0% (108/327). The Q4 group had the highest proportion of neurologically favorable outcome (52.5% [48/91]), followed by Q3 (34.5% [30/87]), Q2 (27.3% [21/77]), and Q1 (12.5% [9/72]). The multivariable logistic regression analysis demonstrated that the proportion of neurologically favorable outcome was significantly higher in the Q4 group than that in the Q1 group (adjusted odds ratio 10.39; 95% confidence interval 3.36-32.17). The adjusted proportion of neurologically favorable outcome increased in a stepwise fashion across increasing quartiles (p < 0.001). In this study, higher serum albumin concentration upon hospital arrival had a positive association with neurologically favorable outcome after OHCA in a dose-dependent manner.

Hemoglobin Normalization Results in Lower Dialysis Dose, Despite High Dialysate Flow. Single Needle Offers Inadequate Dialysis

Anemia correction by erythropoietin favorably affects dialysis outcome but may also reduce dialysis efficiency increasing morbidity and mortality. Single needle dialysis (SN) and high dialysate flow (DF) are dialysis variations. We studied the effect of hemoglobin (Hb) normalization on dialysis adequacy under high DF. We also compared double needle (DN) and SN dialysis efficiency. Seventeen stable anuric patients (13 M, 4 F), aged 62 (40–90), on hemodialysis for 48 months (8–204), were studied in two, 6 months apart, periods of low (A) and high Hb (B), during a midweek 4 h dialysis with DN and SN. DF was 500 in A and 800ml/min in B. Rebound urea samples, 20 min post dialysis, were used for computer calculated double pool urea kinetics.

Hb levels were 128±8 g/L (B) vs. 119±14 g/L (A), P<0.03. Despite the use of higher DF less dialysis was delivered in B vs. A, under DN or SN (DN: URR 64.8±5.8 vs. 69.7±5.2%, Kt/Vequil. 1.09±0.19 vs. 1.26±0.21, nPCR 1.37±0.29 vs. 1.60±0.36g/kg/day, changes <0.001, SN: URR 49.7±7.5% vs. 52.6±8.8%, Kt/Vequil. 0.74±0.16 vs. 0.82±0.23, nPCR 1.05±0.33 vs. 1.20±0.31, changes NS). SN was found significantly (P<0.001) less efficient than DN in A and B. Serum creatinine drop was significantly (P<0.001) less in both periods with SN vs. DN. Hb (SN in B) correlated inversely to Kt/V (r = –0.5705, P<0.02) and URR (r = –0.6432, P=0.005).

Hb correction to normality is associated with a decrease in dialysis efficiency. The use of high dialysate flow does not compensate for this loss. SN delivers inadequate dialysis independently of dialysate flow or hemoglobin concentration.

Aberrant cortical thickness in neurologically asymptomatic patients with end-stage renal disease

PURPOSE

The aim of this study is to investigate the morphology of cortical gray matter in patients with end-stage renal disease (ESRD) and the relationship between cortical thickness and kidney function.

PATIENTS AND METHODS

Three-dimensional high-resolution brain structural magnetic resonance imaging data were collected from 35 patients with ESRD (28 men, 18-61 years old) and 40 age- and gender-matched healthy controls (HCs, 32 men, 22-58 years old). Vertex-wise analysis was then performed to compare the brains of the patients with ESRD with those of HCs to identify abnormalities in the brains of the former. Multiple biochemical measures of renal metabolin, vascular risk factors, general cognitive ability, and dialysis duration were correlated with brain morphometry alterations for the patients.

RESULTS

Patients with ESRD showed lesser cortical thickness than the HCs. The most significant cluster with decreased cortical thickness was found in the right prefrontal cortex (P<0.05, random-field theory correction). In addition, the four local peak vertices in the prefrontal cluster were lateral prefrontal cortex (Peaks 1 and 2), medial prefrontal cortex (Peak 3), and ventral prefrontal cortex (Peak 4). Significant negative correlations were observed between the cortical thicknesses of all four peak vertices and blood urea nitrogen; a negative correlation, between the cortical thickness in three of four peaks and serum creatinine; and a positive correlation, between cortical thickness in the medial prefrontal cortex (Peak 3) and hemoglobin.

CONCLUSION

These results provided compelling evidence for cortical abnormality of ESRD patients and suggested that kidney function may be the key factor for predicting changes of brain tissue structure.

Impact of risk factors on functional status in maintenance hemodialysis patients

Objectives

To survey by measuring patient’s functional status which is crucial when end-stage renal disease patients begin a dialysis program. The influence of the disease on patients can be examined by the measurement of Karnofsky Performance Status (KPS) scores, together with a quality of life survey, and clinical variables.

Methods

The details for the dataset in the study were collected from patients receiving regular hemodialysis (HD) in one hospital, which were available retrospectively for 1166 patients during the 5-year study period. KPS scores were applied for quantifying functional status. To identify risk factors for functional status, clinical factors including demographics, laboratory data, and HD vintage were selected. This study applied a classification and regression tree approach (CART) and logistic regression to determine risk factors on functional impairment among HD patients.

Results

Ten risk factors were identified by CART and regression model (age, primary kidney disease subclass, treatment years, hemoglobin, albumin, creatinine, phosphorus, intact parathyroid hormone, ferritin, and cardiothoracic ratio). The results of logistic regression with selected interaction models showed older age or higher hematocrit, blood urea nitrogen, and glucose levels could significantly increase the log-odds of obtaining low KPS scores at in-person visits.

Conclusions

In interaction results, the combination of older age with higher albumin level and higher creatinine level with longer HD treatment years could significantly decrease the log-odds of a low KPS score assessment during in-person visits. Age, hemoglobin, albumin, urea, creatinine levels, primary kidney disease subclass, and HD duration are the major determinants for functional status in HD patients.

Electronic supplementary material

The online version of this article (10.1186/s40001-017-0298-1) contains supplementary material, which is available to authorized users.

Online measurement of hemodialysis adequacy using effective ionic dialysance of sodium-a review of its principles, applications, benefits, and risks

Dialysis dose is an important determinant of clinical outcomes in patients with end stage renal disease on maintenance dialysis. In clinical practice dialysis dose is monitored at least monthly by urea clearance based on Urea Kinetic Modeling. Online clearance monitoring using effective ionic dialysance (EID) of sodium (Na⁺ ) is available on some hemodialysis machines. This paper reviews the background, methodology, additional applications, and potential risks associated with EID. Effective ionic dialysance provides a reliable, real-time, noninvasive, and inexpensive measurement of dialysis dose during an ongoing hemodialysis (HD) session to allow interventions and assess the impact of these changes on clearance. Surveillance of vascular access flow rates can be used to screen for access dysfunction and refer for interventions. There is a concern that EID measurements may cause Na⁺ loading because of high dialysate Na⁺ used during these measurements, however, mathematical models, in vitro experiments, and clinical studies in patients on maintenance HD do not show any evidence of Na⁺ loading during EID measurements. We cannot rule out the possibility of nonosmotic Na⁺ accumulation in the skin because no published literature exists on this topic as it pertains to clearance measurements based on EID of Na⁺ .

Hypoalbuminemia and Clinical Outcomes: What is the Mechanism behind the Relationship?

Albumin has a number of important physiologic functions, which include maintaining oncotic pressure, transporting various agents (fatty acids, bile acids, cholesterol, metal ions, and drugs), scavenging free oxygen radicals, acting as an antioxidant, and exerting an antiplatelet effect. Hypoalbuminemia in adults, defined by an intravascular albumin level of <3.5 g/dL, is associated with poor postoperative outcomes in patients undergoing surgical intervention. Although the relationship of hypoalbuminemia and poor surgical outcome has been known for many years, the pathophysiology behind the relationship is unclear. Three theoretical constructs might explain this relationship. First, albumin might serve as a nutritional marker, such that hypoalbuminemia represents poor nutritional status in patients who go on to experience poor postoperative outcomes. Second, albumin has its own pharmacologic characteristics as an antioxidant or transporter, and therefore, the lack of albumin might result in a deficiency of those functions, resulting in poor postoperative outcomes. Or third, albumin is known to be a negative acute phase protein, and as such hypoalbuminemia might represent an increased inflammatory status of the patient, potentially leading to poor outcomes. A thorough review of the literature reveals the fallacy of these arguments and fails to show a direct cause and effect between low albumin levels per se and adverse outcomes. Interventions designed solely to correct preoperative hypoalbuminemia, in particular intravenous albumin infusion, do little to change the patient's course of hospitalization. While surgeons may use albumin levels on admission for their prognostic value, they should avoid therapeutic strategies whose main endpoint is correction of this abnormality.

Associations of adiponectin and leptin levels with protein-energy wasting, in end stage renal disease patients

OBJECTIVE

The aim of the study was to examine the prevalence of protein-energy wasting (PEW) in hemodialysis (HD) and peritoneal dialysis (PD) patients in our center and determine whether adiponectin and leptin are involved in the development of PEW.

DESIGN

Prospective (18 months).

SETTING

University Hospital of Heraklion, Crete, Greece.

SUBJECTS

Seventy-four end-stage-renal-disease patients, 47 on HD and 27 on PD.

MAIN OUTCOME MEASURES

At three sequential time points (baseline, 6 and 18 months) anthropometric, nutritional and inflammatory status data were collected. Serum adiponectin and leptin were also assessed at each time point. Patients were allocated to 3 strata according to PEW severity (0, 1-2 and ≥3 criteria for PEW).

RESULTS

Adiponectin and leptin levels were greater among PD compared to HD patients (p≤0.035). Adiponectin levels were incrementally greater across increasing strata of PEW (p≤0.002). Leptin showed the opposite trend, with lower levels in malnourished patients and higher levels in patients with zero PEW criteria (p≤0.042). Alterations of adiponectin levels during the observation period were dependent on PEW stratum (p≤0.021) and mode of dialysis (p≤0.002), after adjustment for age, dialysis vintage, gender and fat mass index. Particularly, adiponectin levels increased over time in HD patients with ≥3 criteria for PEW, whereas adiponectin levels decreased in PD patients with ≥3 criteria for PEW throughout the study. Leptin alterations over time were not affected by dialysis mode or PEW stratification.

CONCLUSIONS

Our study provides evidence that increased adiponectin and decreased leptin levels are independently associated with PEW and thus, poor prognosis.

The additional benefit of weighted subjective global assessment (SGA) for the predictability of mortality in incident peritoneal dialysis patients: A prospective study

Although subjective global assessment (SGA) is a widely used tool for nutritional investigation, the scores are dependent on the inspectors' subjective opinions, and there are only few studies that directly assessed the usefulness of SGA and modified SGA in incident peritoneal dialysis (PD) patients. A total of 365 incident PD patients between 2009 and 2015 were enrolled and measured with SGA and calculated using serum albumin and total iron binding capacity (TIBC) levels for weighted SGA. Cox analyses were performed to delineate the association between SGA or weighted SGA and all-cause mortality, and a receiver-operating characteristic was conducted to reveal the additional benefit of weighted SGA on predicting adverse clinical outcomes. The Kaplan-Meier curve showed that the cumulative survival rate in patients with "Good nutrition" (G1) was significantly higher compared to those with "Mild to severe malnutrition" (G2). G2 was significantly associated with an increase in the mortality even after adjusting for several covariates compared with G1. Moreover, a 1-unit increase in weighted SGA was also significantly correlated with mortality after adjustment of the same covariates, while G2 was not significantly associated with an increase in the mortality among young-aged (under 65 years) groups. Meanwhile, a 1-unit increase in weighted SGA was significantly related to an increase in mortality in all the subgroup analyses. Furthermore, the AUCs of weighted SGAs in all groups were significantly increased compared with those of SGA alone. In conclusions, the evaluation of nutritional status based on SGA in incident PD patients might be useful for predicting mortality. However, weighted SGA with serum albumin and TIBC can provide additional predictive power for mortality compared with SGA alone in incident PD patients.

Characterization and Correction of Olfactory Deficits in Kidney Disease

Patients with CKD suffer from food aversion, anorexia, and malnutrition. Although olfaction has a significant role in determining food flavor, our understanding of olfactory impairment and of the olfaction-nutrition axis in patients with kidney disease is limited. We quantified odor identification, odor threshold, and subjective odor perception in a cohort (n=161) comprising 36 participants with CKD, 100 participants with ESRD, and 25 controls. We investigated olfaction-nutrition associations in these participants and examined a novel intervention to improve olfaction in ESRD. The mean odor identification score was lower in patients with CKD (75.6%±13.1%; P=0.02) and ESRD (66.8%±15.1%; P<0.001) than in controls (83.6%±11.4%). Patients with ESRD exhibited higher odor threshold than the remaining participants exhibited. All groups had similar scores for subjective smell assessment. In multivariable adjusted analyses, kidney disease associated with increased odds of odor identification deficits (odds ratio, 4.80; 95% confidence interval, 1.94 to 11.89). A reduction in odor identification score was associated with higher subjective global assessment score and lower serum total cholesterol, LDL cholesterol, and albumin concentrations. We found no associations between odor threshold and nutritional parameters. In a proof of concept, 6-week, open-label clinical trial, intranasal theophylline (an epithelial membrane transport and proton secretion activator) increased odor identification score in five out of seven (71%) patients with ESRD. In conclusion, patients with kidney disease have olfactory deficits that may influence their nutritional status. Our preliminary results regarding olfactory improvement using intranasal theophylline warrant confirmation in a randomized controlled trial.

Does Whey Protein Supplementation Improve the Nutritional Status in Hypoalbuminemic Peritoneal Dialysis Patients?

Limited data are available regarding the effects of whey protein on the nutritional status of the peritoneal dialysis population. This study evaluated the effects of whey protein supplementation for 12 weeks on the nutritional status in hypoalbuminemic peritoneal dialysis patients. Thirty-six stable adult patients on maintenance peritoneal dialysis with serum albumin levels <3.5 g/dL were enrolled in the study and were divided into two groups similar in their serum albumin and normalized protein equivalent of total nitrogen appearance (nPNA). Nineteen patients were instructed to receive 1.2 g/kg per day of protein diet and additional whey protein supplement at a dose of 25% of the instructed daily protein diet (whey protein group), and 17 patients were instructed to receive 1.2 g/kg per day protein diet without additional whey protein supplementation (control group). Nutritional status was assessed using two measures: nPNA and lean tissue mass index (LTI) obtained by whole-body bioimpedance spectroscopy technique. In the whey protein group serum albumin and nPNA significantly increased from baseline to week 6 (P < 0.001, P = 0.034; respectively) and from week 6 to week 12 (P < 0.001, P = 0.001; respectively); LTI significantly increased from week 6 to week 12 (P = 0.022). Compared to the control group at week 12, serum albumin, nPNA and LTI values were significantly higher in the whey protein group (P < 0.001, P = 0.002, P = 0.001; respectively). This study demonstrated for the first time that oral supplementation with whey protein improves nutritional status and is well tolerated in hypoalbuminemic PD patients.

Quantification and Dosing of Renal Replacement Therapy in Acute Kidney Injury: A Reappraisal

BACKGROUND/AIMS

Delivered dialysis therapy is routinely measured in the management of patients with end-stage renal disease; yet, the quantification of renal replacement prescription and delivery in acute kidney injury (AKI) is less established. While continuous renal replacement therapy (CRRT) is widely understood to have greater solute clearance capabilities relative to intermittent therapies, neither urea nor any other solute is specifically employed for CRRT dose assessments in clinical practice at present. Instead, the normalized effluent rate is the gold standard for CRRT dosing, although this parameter does not provide an accurate estimation of actual solute clearance for different modalities.

METHODS

Because this situation has created confusion among clinicians, we reappraise dose prescription and delivery for CRRT.

RESULTS

A critical review of RRT quantification in AKI is provided.

CONCLUSION

We propose an adaptation of a maintenance dialysis parameter (standard Kt/V) as a benchmark to supplement effluent-based dosing of CRRT. Video Journal Club "Cappuccino with Claudio Ronco" at http://www.karger.com/?doi=475457.

Assessing value-based health care delivery for haemodialysis

RATIONALE, AIMS AND OBJECTIVES

Disparities in haemodialysis outcomes among centres have been well-documented. Besides, attempts to assess haemodialysis results have been based on non-comprehensive methodologies. This study aimed to develop a comprehensive methodology for assessing haemodialysis centres, based on the value of health care. The value of health care is defined as the patient benefit from a specific medical intervention per monetary unit invested (Value = Patient Benefit/Cost). This study assessed the value of health care and ranked different haemodialysis centres.

METHOD

A nephrology quality management group identified the criteria for the assessment. An expert group composed of stakeholders (patients, clinicians and managers) agreed on the weighting of each variable, considering values and preferences. Multi-criteria methodology was used to analyse the data. Four criteria and their weights were identified: evidence-based clinical performance measures = 43 points; yearly mortality = 27 points; patient satisfaction = 13 points; and health-related quality of life = 17 points (100-point scale). Evidence-based clinical performance measures included five sub-criteria, with respective weights, including: dialysis adequacy; haemoglobin concentration; mineral and bone disorders; type of vascular access; and hospitalization rate. The patient benefit was determined from co-morbidity-adjusted results and corresponding weights. The cost of each centre was calculated as the average amount expended per patient per year.

RESULTS

The study was conducted in five centres (1-5). After adjusting for co-morbidity, value of health care was calculated, and the centres were ranked. A multi-way sensitivity analysis that considered different weights (10-60% changes) and costs (changes of 10% in direct and 30% in allocated costs) showed that the methodology was robust. The rankings: 4-5-3-2-1 and 4-3-5-2-1 were observed in 62.21% and 21.55%, respectively, of simulations, when weights were varied by 60%.

CONCLUSIONS

Value assessments may integrate divergent stakeholder perceptions, create a context for improvement and aid in policy-making decisions.

Higher Ultrafiltration Rate Is Associated with Longer Dialysis Recovery Time in Patients Undergoing Conventional Hemodialysis

BACKGROUND

Increased mortality and morbidity are reported in association with high ultrafiltration rate (UFR) and with long dialysis recovery time (DRT). We studied the association between UFR and DRT.

METHODS

This is a cross-sectional, observational study was conducted. Patients on thrice-weekly hemodialysis (HD) with self-reported DRT between August and December 2014 were included. We examined the association of 30-day average UFR with recovery time.

RESULTS

The total number of patients included in this study was 2,689. DRT in categories of immediate recovery, >0-≤2, >2-≤6, >6-≤12, and >12 h, were reported in 27, 28, 17, 9, and 20% of the patients respectively. In multivariable analysis, longer DRT was associated with female gender, non-black race, higher body weight, lower serum albumin, chronic heart failure, cerebrovascular disease, missed dialysis sessions, higher pre-dialysis systolic blood pressure, and larger UF volume. Compared to UFR of <10, UFR ≥13 mL/kg/h was associated with longer DRT, OR of 1.16 (95% CI 0.99-1.36), and 1.28 (95% CI 1.06-1.54) in the unadjusted and the adjusted analyses respectively. Intradialytic hypotension was also associated with longer DRT in the unadjusted (per 10% higher frequency, OR 1.04 [95% CI 1.01-1.07]) and adjusted analyses (OR 1.03 [95% CI 1.00-1.07]).

CONCLUSION

Long recovery time is common after HD. Rapid fluid removal is associated with longer DRT.

A Practical Standardized Composite Nutrition Score Based on Lean Tissue Index: Application in Nutrition Screening and Prediction of Outcome in Hemodialysis Population

OBJECTIVE

Rapid screening and monitoring of nutritional status is mandatory in hemodialysis population because of the increasingly encountered nutritional problems. Considering the limitations of previous composite nutrition scores applied in this population, we tried to develop a standardized composite nutrition score (SCNS) using low lean tissue index as a marker of protein wasting to facilitate clinical screening and monitoring and to predict outcome.

DESIGN AND METHODS

This retrospective cohort used 2 databases of dialysis populations from Taiwan between 2011 and 2014. First database consisting of data from 629 maintenance hemodialysis patients was used to develop the SCNS and the second database containing data from 297 maintenance hemodialysis patients was used to validate this developed score.

RESULTS

SCNS containing albumin, creatinine, potassium, and body mass index was developed from the first database using low lean tissue index as a marker of protein wasting. When applying this score in the original database, significantly higher risk of developing protein wasting was found for patients with lower SCNS (odds ratio 1.38 [middle tertile vs highest tertile, P < .0001] and 2.40 [lowest tertile vs middle tertile, P < .0001]). The risk of death was also shown to be higher for patients with lower SCNS (hazard ratio 4.45 [below median level vs above median level, P < .0001]). These results were validated in the second database.

CONCLUSION

We developed an SCNS consisting of 4 easily available biochemical parameters. This kind of scoring system can be easily applied in different dialysis facilities for screening and monitoring of protein wasting. The wide application of body composition monitor in dialysis population will also facilitate the development of specific nutrition scoring model for individual facility.

Associations of Dietary Protein and Energy Intakes With Protein-Energy Wasting Syndrome in Hemodialysis Patients

Introduction

The associations of dietary protein and/or energy intakes with protein or energy wasting in patients on maintenance hemodialysis are controversial. We examined these in the Hemodialysis (HEMO) Study.

Methods

In 1487 participants in the HEMO Study, baseline dietary protein intake (grams per kilogram per day) and dietary energy intake (kilocalories per kilograms per day) were related to the presence of the protein-energy wasting (PEW) syndrome at month 12 (defined as the presence of at least 1 criteria in 2 of the 3 categories of low serum chemistry, low body mass, and low muscle mass) in logistic regression models. In additional separate models, protein intake estimated from equilibrated normalized protein catabolic rate (enPCR) was also related to the PEW syndrome.

Results

Compared with the lowest quartile, the highest quartile of baseline dietary protein intake was paradoxically associated with increased risk of the PEW syndrome at month 12 (odds ratio [OR]: 4.11; 95% confidence interval [CI]: 2.79-6.05). This relationship was completely attenuated (OR: 1.35; 95% CI: 0.88-2.06) with adjustment for baseline body weight, which suggested mathematical coupling. Results were similar for dietary energy intake. Compared with the lowest quartile of baseline enPCR, the highest quartile was not associated with the PEW syndrome at 12 months (OR: 0.78; 95% CI: 0.54-1.12).

Discussion

These data do not support the use of dietary protein intake or dietary energy intake criteria in the definition of the PEW syndrome in patients on maintenance hemodialysis.

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.

Association of low serum albumin concentration and adverse cardiovascular events in stable coronary heart disease

OBJECTIVE

Coronary heart disease (CHD) is a leading cause of death in developed countries. Exploration of indicators to identify high risk individuals who develop adverse outcomes despite stable baseline condition is important. This study is to evaluate the association between serum albumin concentration and cardiovascular (CV) outcomes in individuals of stable CHD.

METHODS

Seven-hundred-thirty-four participants from Biosignature study, a nationwide prospective cohort study aimed to identity risk factors among patients with stable CHD, were enrolled for analysis. They were divided into low serum albumin group (baseline albumin concentration <3.5g/dL, n=98) and normal albumin group (baseline albumin concentration ≥3.5g/dL, n=636). The relations between baseline albumin and adverse CV outcomes within 18months of follow-up were analyzed.

RESULTS

Compared baseline characteristics with normal albumin group, subjects in low albumin group are older, having more diabetic patients, lower hemoglobin level, lower estimated glomerular filtration rate, lower total cholesterol level, lower left ventricular ejection fraction, and higher blood glucose. While there is no significant difference of total CV events between two groups, low serum albumin concentration is associated with an increased risk of all-cause mortality (10.2% vs. 0.5%, p<0.001) and hard CV events (7.1% vs. 1.4%, p<0.001). The association remains significant after adjustments for confounders (all-cause mortality, HR: 6.81, 95% CI: 1.01-45.62; hard CV events, HR: 3.68, 95% CI: 1.03-13.19).

CONCLUSIONS

Low serum albumin concentration (<3.5g/dL) worsens prognosis of patients with stable CHD.

Risk factors for mortality in patients undergoing hemodialysis: A systematic review and meta-analysis

BACKGROUND

No consensus exists regarding the factors influencing mortality in patients undergoing hemodialysis (HD). This meta-analysis aimed to evaluate the impact of various patient characteristics on the risk of mortality in such patients.

METHODS

PubMed, Embase, and Cochrane Central were searched for studies evaluating the risk factors for mortality in patients undergoing HD. The factors included age, gender, diabetes mellitus (DM), body mass index (BMI), previous cardiovascular disease (CVD), HD duration, hemoglobin, albumin, white blood cell, C-reactive protein (CRP), parathyroid hormone, total iron binding capacity (TIBC), iron, ln ferritin, adiponectin, apolipoprotein A1 (ApoA1), ApoA2, ApoA3, high-density lipoprotein (HDL), total cholesterol, hemoglobin A1c (HbA1c), serum phosphate, troponin T (TnT), and B-type natriuretic peptide (BNP). Relative risks with 95% confidence intervals were derived. Data were synthesized using the random-effects model.

RESULTS

Age (per 1-year increment), DM, previous CVD, CRP (higher versus lower), ln ferritin, adiponectin (per 10.0μg/mL increment), HbA1c (higher versus lower), TnT, and BNP were associated with an increased risk of all-cause mortality. BMI (per 1kg/m² increment), hemoglobin (per 1d/dL increment), albumin (higher versus lower), TIBC, iron, ApoA2, and ApoA3 were associated with reduced risk of all-cause mortality. Age (per 1-year increment), gender (women versus men), DM, previous CVD, HD duration, ln ferritin, HDL, and HbA1c (higher versus lower) significantly increased the risk of cardiac death. Albumin (higher versus lower), TIBC, and ApoA2 had a beneficial impact on the risk of cardiac death.

CONCLUSIONS

Multiple markers and factors influence the risk of mortality and cardiac death in patients undergoing HD.

Consequences of increasing convection onto patient care and protein removal in hemodialysis

INTRODUCTION

Recent randomised controlled trials suggest that on-line hemodiafiltration (OL-HDF) improves survival, provided that it reaches high convective volumes. However, there is scant information on the feasibility and the consequences of modifying convection volumes in clinics.

METHODS

Twelve stable dialysis patients were treated with high-flux 1.8 m2 polysulphone dialyzers and 4 levels of convection flows (QUF) based on GKD-UF monitoring of the system, for 1 week each. The consequences on dialysis delivery (transmembrane pressure (TMP), number of alarms, % of achieved prescribed convection) and efficacy (mass removal of low and high molecular weight compounds) were analysed.

RESULTS

TMP increased exponentially with QUF (p<0.001 for N >56,000 monitoring values). Beyond 21 L/session, this resulted into frequent TMP alarms requiring nursing staff interventions (mean ± SEM: 10.3 ± 2.2 alarms per session, p<0.001 compared to lower convection volumes). Optimal convection volumes as assessed by GKD-UF-max were 20.6 ± 0.4 L/session, whilst 4 supplementary litres were obtained in the maximum situation (24.5 ± 0.6 L/session) but the proportion of sessions achieving the prescribed convection volume decreased from 94% to only 33% (p<0.001). Convection increased high molecular weight compound removal and shifted the membrane cut-off towards the higher molecular weight range.

CONCLUSIONS

Reaching high convection volumes as recommended by the recent RCTs (> 20L) is feasible by setting an HDF system at its optimal conditions based upon the GKD-UF monitoring. Prescribing higher convection volumes resulted in instability of the system, provoked alarms, was bothersome for the nursing staff and the patients, rarely achieved the prescribed convection volumes and increased removal of high molecular weight compounds, notably albumin.

Associations of Protein-Energy Wasting Syndrome Criteria With Body Composition and Mortality in the General and Moderate Chronic Kidney Disease Populations in the United States

Introduction

It is unknown whether the criteria used to define protein−energy wasting (PEW) syndrome in dialysis patients reflect protein or energy wasting in the general and moderate CKD populations.

Methods

In 11,834 participants in the 1999 to 2004 National Health and Nutrition Examination Survey, individual PEW syndrome criteria and the number of PEW syndrome categories were related to lean body and fat masses (measured by dual-energy absorptiometry) using linear regression in the entire cohort and CKD subpopulation.

Results

Serum chemistry, body mass, and muscle mass PEW criteria tended to be associated with lower lean body and fat masses, but the low dietary protein and energy intake criteria were associated with significantly higher protein and energy stores. When the number of PEW syndrome categories was defined by nondietary categories alone, there was a monotonic inverse relationship with lean body and fat masses and a strong positive relationship with mortality. In contrast, when dietary category alone was present, mean body mass index was in the obesity range; the additional presence of 2 nondietary categories was associated with lower body mass index and lower lean body and fat masses. Thus, the association of a dietary category plus 2 additional nondietary categories with lower protein or energy stores was driven by the presence of the 2 nondietary categories. Results were similar in CKD subgroup.

Discussion

Hence, a definition of PEW syndrome without dietary variables has face validity and reflects protein or energy wasting.

Protein and Energy Depletion in Chronic Hemodialysis Patients: Clinical Applicability of Diagnostic Tools

Protein and energy depletion states are common and associated with increased morbidity and mortality in chronic hemodialysis (CHD) patients. Therefore, proper use of diagnostic tools to assess depleted states in CHD patients is critical. Assessment of protein and energy status can be done by an array of methodologies that include simple estimates of the visceral and somatic pools of protein to more refined techniques to measure protein and energy balance. The nutritional and metabolic derangements in the CHD population are highly complex and can be confounded by multiple comorbidities and fluid shifts between body compartments. Therefore, assessment of protein and energy status in CHD patients requires a wide range of methodologies that not only identify depleted states but also monitor nutrition therapy and predict clinical outcome. Most important, these methods require cautious and individualized interpretation in order to minimize the interference of comorbid conditions frequently observed in the CHD population. Currently, there is not a single method that can be considered the gold standard for assessment of protein and energy status in CHD patients. Therefore, a combination of methods is recommended. In this review, we describe available methods to assess protein and energy status, with special considerations pertaining to CHD patients.

The association between physical activity and mortality among patients undergoing maintenance hemodialysis

The aim of this study was to assess whether physical activity can predict mortality in patients undergoing maintenance hemodialysis (MHD). This observational study enrolled 317 patients undergoing MHD from Shanxi Provincial People Hospital and the Second Affiliated Hospital of Xi'an Medical University from February to June 2012. Physical activity was measured by using the Human Activity Profile (HAP) and the Stanford 7-day Physical Activity Recall Questionnaire (PAR). Exercise or not, maximal activity score (MAS), adjusted activity score (AAS), light physical activities, moderate physical activities, and the PAR value were significantly associated with mortality among patients undergoing MHD. The patients with higher scores of maximal activity score (MAS), adjusted activity score (AAS), and PAR value; more hours of the light physical activities; and moderate physical activities have the lower mortality. Through multivariate Cox regression analysis, adjusting for age, MAS, PAR value, and light physical activities can predict the mortality among patients undergoing MHD (P < .05), and the relative risk values were 0.44, 0.69, and 0.66, respectively. Baseline physical activities are independent predictors of mortality in patients undergoing hemodialysis.

Clinical outcomes and quality of life in hemodialysis diabetic patients versus non-diabetics

Background

Diabetes is the leading cause of end stage renal disease (ESRD) worldwide.

Objectives

We compared the clinical outcomes in diabetic patients on hemodialysis (HD) with non-diabetics.

Patients and Methods

Adult maintenance HD patients (N= 532) from 9 HD facilities were enrolled to this prospective cohort study in September 2012. Causes of death, hospitalization, and HD exit were recorded in a median 28 months follow up period.

Results

Forty-one percent of patients were diabetic. Diabetic patients compared to non-diabetics had significantly higher age (62.2 ± 11.2 versus 53.1 ± 16.7 years), lower dialysis duration (median: 23 versus 30 months), more cardiovascular comorbidities (64% versus 28%) , higher C-reactive protein (CRP) levels (median: 3.80 versus 2.25 mg/L), lower serum albumin (3.86 ± 0.35 versus 3.93 ± 0.35 g/dL), lower intact parathyroid hormone (iPTH) (median: 272 versus 374 ρg/mL), higher serum triglyceride (167 ± 91 versus 139 ± 67 mg/dL) and low density lipoprotein (LDL) (82.5 ± 24.5 versus 77.5 ± 23.8 mg/dL), and worse short form health survey (SF36) score (45.7 ± 20.9 versus 52.7 ± 20.5). Annual admission rate was higher in diabetics (median: 0.86 versus 0.43) and diabetic foot involved 16% of their admissions. Transplantation rate was 4 and 9 per 100 patient years in diabetics and non-diabetics, respectively. Death rate was two folds higher in diabetics (24 versus 12 per 100 patient years). Cardiovascular diseases ( ± infections/other causes) comprised 80.5% of death in diabetics and 54.5% in non-diabetics. In Cox regression proportional hazard multivariate analysis, hazard risk of death in diabetics was 1.9 times higher than non-diabetics.

Conclusions

Clinical outcomes and health related quality of life (HRQOL) are much worse in diabetic compared to non-diabetic HD patients mainly due to more frequent of cardiovascular diseases (CVDs).

The relationship between dialysis adequacy and serum uric acid in dialysis patients; a cross-sectional multi-center study in Iranian hemodialysis centers

Introduction: Uric acid is one of the most significant uremic toxins accumulating in chronic renal failure patients treated with standard dialysis. Its clearance has not any exact relation with urea and creatinine clearance.

Objectives: The aim of this study was to investigate the relationship between adequacy of dialysis and serum level of uric acid in dialysis patients of some dialysis centers in Iran.

Patients and Methods: In this study 1271 hemodialysis patients who have been treated for more than 3 months were evaluated. Their information and examinations from their files in all over the country were gathered and analyzed using SPSS versin18.0.

Results: In this study, a significant relationship between dialysis duration and serum level of uric acid was not detected, however, a significant relationship between patients Kt/V and uric acid (R=0.43, P=0.029) was seen. Patients who had higher adequacy of dialysis had a higher level of plasma uric acid.

Conclusion: For better controlling of plasma uric acid level of hemodialysis patients, increasing of the adequacy of dialysis or its duration is not effective. Other modalities of decreasing of serum uric acid like, changing diet or lifestyle or medical therapy may be necessary.

Continuous Ambulatory Peritoneal Dialysis in Patients with HIV and End-Stage Renal Failure

♦ BACKGROUND: This study aimed to evaluate the differences in continuous ambulatory peritoneal dialysis (CAPD)-related outcomes according to human immunodeficiency virus (HIV) status of end-stage renal failure patients. ♦ METHODS: This prospective cohort study included 70 HIV-negative and 70 HIV-positive consecutive patients with renal failure who underwent dialysis with newly inserted Tenckhoff catheters between September 2012 and February 2015. Patients were followed up monthly at a central renal clinic for 1 year or until the primary endpoints of technique failure or death. ♦ RESULTS: Technique failure rates were similar (HIV-negative: 0.270 episodes/person-year; HIV-positive: 0.298 episodes/person-year; hazard ratio [HR], 1.09; 95% confidence interval [CI], 0.51 - 2.32; p = 0.822). However, there were fewer HIV-positive patients with complete 1-year follow-up with a patent catheter (42.9% vs 58.6% in the HIV-negative cohort; p = 0.063) owing to their higher all-cause mortality rate (0.55 vs 0.25 deaths/person-year, respectively; HR, 2.11; CI, 1.07 - 4.14; p = 0.031). Cluster of differentiation 4 count (CD4) < 200/μL (HR, 5.39; CI, 2.20 - 13.21; p < 0.001) and unsuppressed viral load (HR, 3.63; CI 1.72 - 7.67; p = 0.001) were associated with increased mortality hazards. Rates of first peritonitis were 0.616 (HIV-negative) and 1.668 (HIV-positive) episodes/person-year (HR, 2.38; CI, 1.46 - 3.89; p = 0.001). All-cause admission rates were 1.52 (HIV-negative) and 2.97 (HIV-positive) hospital admissions/person-year (HR, 1.66; CI, 1.12 - 2.48; p = 0.013). ♦ CONCLUSION: Although HIV-seropositive status of patients on CAPD did not adversely influence technique failure rates or patency at 1 year, uncontrolled HIV infection may be associated with increased relative risk of mortality and morbidity.

Changes in urine volume and serum albumin in incident hemodialysis patients

INTRODUCTION

Hypoalbuminemia is a predictor of poor outcomes in dialysis patients. Among hemodialysis patients, there has not been prior study of whether residual kidney function or decline over time impacts serum albumin levels. We hypothesized that a decline in residual kidney function is associated with an increase in serum albumin levels among incident hemodialysis patients.

METHODS

In a large national cohort of 38,504 patients who initiated hemodialysis during 1/2007-12/2011, we examined the association of residual kidney function, ascertained by urine volume and renal urea clearance, with changes in serum albumin over five years across strata of baseline residual kidney function, race, and diabetes using case-mix adjusted linear mixed effects models.

FINDINGS

Serum albumin levels increased over time. At baseline, patients with greater urine volume had higher serum albumin levels: 3.44 ± 0.48, 3.50 ± 0.46, 3.57 ± 0.44, 3.59 ± 0.45, and 3.65 ± 0.46 g/dL for urine volume groups of <300, 300-<600, 600-<900, 900-<1,200, and ≥1,200 mL/day, respectively (P_trend  < 0.001). Over time, urine volume and renal urea clearance declined and serum albumin levels rose, while the baseline differences in serum albumin persisted across groups of urinary volume. In addition, the rate of decline in residual kidney function was not associated with the rate of change in albumin.

DISCUSSION

Hypoalbuminemia in hemodialysis patients is associated with lower residual kidney function. Among incident hemodialysis patients, there is a gradual rise in serum albumin that is independent of the rate of decline in residual kidney function, suggesting that preservation of residual kidney function does not have a deleterious impact on serum albumin levels.

Factors associating with oxygenation of lower-limb muscle tissue in hemodialysis patients

AIM

To evaluate the lower-limb muscle oxygenation in hemodialysis (HD) patients and identify the factors associating with muscle oxygenation.

METHODS

Sixty-seven HD patients (53 men and 14 women; mean age, 67.1 ± 1.2 years; mean HD duration, 5.6 ± 0.9 years) were recruited. In addition, 15 healthy individuals (nine men and six women; mean age, 38.2 ± 4.6 years) were recruited as the control group. Lower-limb muscle regional saturation of oxygen (rSO₂) was monitored on the lateral side of the gastrocnemius muscle before HD using an INVOS 5100C (Covidien Japan, Tokyo, Japan), which utilizes near-infrared spectroscopy. Here, we evaluated the association between lower-limb muscle rSO₂ and clinical parameters.

RESULTS

The rSO₂ values were significantly lower in patients undergoing HD than in healthy individuals (50.0% ± 1.7% vs 76.8% ± 2.5%, P < 0.001). Lower-limb muscle rSO₂ showed significant positive correlations with diastolic blood pressure, blood urea nitrogen concentration, serum creatinine concentration, serum potassium concentration, serum inorganic phosphate concentration, and serum albumin concentration as well as negative correlation with HD duration. We conducted a multiple linear regression analysis using parameters that were significantly correlated with the lower-limb muscle rSO₂ in a simple linear regression analysis. Multiple regression analysis demonstrated that lower-limb muscle rSO₂ was independently associated with serum inorganic phosphate (standardized coefficient: 0.27) and serum albumin concentrations (standardized coefficient: 0.24). In addition, there were no differences in lower-limb muscle rSO₂ between diabetic and non-diabetic HD patients. This study has several limitations. Firstly, its sample size was relatively small. Secondly, we could not evaluate the association between lower-limb muscle rSO₂ and calculated nutritional markers, including normalized protein catabolic rate and body mass index, anthropometric measurements representing nutritional status, and the severity of protein-energy wasting. Finally, we did not routinely examine the arterial vascular status of HD patients without symptoms of peripheral artery disease. As such, it is possible that some HD patients with subclinical peripheral artery disease may have been included in this study.

CONCLUSION

In HD patients, the oxygenation of lower-limb muscle tissue was associated with serum inorganic phosphate and albumin concentrations, both of which represent nutritional status.

More Dialysis Has Not Proven Much Better

Patients maintained on standard three times weekly hemodialysis have a high mortality rate and a limited quality of life. Some of this illness is due to systemic diseases that have caused kidney failure, and thus may be irreversible. But we presume that imperfect replacement of normal kidney function by dialysis contributes importantly. Patients on hemodialysis are subject to fluctuations in extracellular fluid volume and inorganic ion concentrations and their plasma levels of many organic waste solutes remain very high. It is thus natural to suppose that their health could be improved by increasing the intensity of dialysis treatment. But despite a great deal of work over the past 20 years, evidence that such improvement can be obtained is generally lacking. Specific benefits can indeed be achieved. Patients who cannot control their intradialytic weight gains or plasma phosphate levels with standard therapy can benefit from extending treatment time. But we cannot promise the average patient that longer or more frequent treatment will reduce mortality or improve the quality of life.

Association between Low Dietary Protein Intake and Geriatric Nutrition Risk Index in Patients with Chronic Kidney Disease: A Retrospective Single-Center Cohort Study

Reduced dietary protein intake in malnourished patients with chronic kidney disease (CKD) may be associated with adverse clinical outcomes, which may mask any efficacy of a low-protein diet. The study included 126 patients with CKD who attended a dedicated dietary counseling clinic in 2005-2009 and were systematically followed until January 2015. Of these patients, 20 (15.9%) had moderate or severe nutrition-related risk of geriatric nutritional risk index (GNRI) < 92; these patients were more likely to be older, have a greater proteinuria, and have lower body mass index and serum albumin concentration. Dietary protein intake was significantly lower in older patients (r = -0.33, p < 0.001) and those with lower glomerular filtration rate (r = 0.47, p < 0.001). The non-protein to nitrogen calorie ratio was independently associated with GNRI. Reduced GNRI was significantly associated with mortality (hazard ratio (HR) = 4.94; 95% confidence interval (CI) = 1.61-15.42, p = 0.012) and cardiovascular events (HR = 9.37; 95% CI = 2.49-37.34, p = 0.006), but not with adverse renal outcomes. Restricting protein intake may be harmful to patients with any nutrition-related risk, suggesting that improvement of nutritional status should be a high priority.

Longitudinal Changes in Protein Carbamylation and Mortality Risk after Initiation of Hemodialysis

BACKGROUND AND OBJECTIVES

Carbamylation describes a post-translational protein modification associated with adverse outcomes in ESRD, but the risk implications of changes in carbamylation over time are not well understood.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We investigated the 1-year natural history of protein carbamylation in patients initiating maintenance hemodialysis and determined the prognostic value of longitudinal carbamylation changes in relation to mortality. In a nested patient-control study, we measured serial carbamylated albumin concentrations in select participants from a large incident dialysis cohort followed from 2004 to 2005 (n=10,044); 122 individuals who survived at least 90 days but died within 1 year of initiating hemodialysis (patients) were randomly selected along with 244 individuals who survived for at least 1 year (controls; matched for demographics). Carbamylated albumin concentration was measured using plasma collected at dialysis initiation and every subsequent 90-day period until 1 year or death.

RESULTS

Baseline carbamylated albumin concentration was similar between controls and patients (mean±SD; 18.9±0.7 and 19.8±1.1 mmol/mol, respectively; P=0.94). From dialysis initiation to day 90, carbamylated albumin concentration markedly fell in all patients, with controls -9.9±0.8 mmol/mol (P<0.001) and patients -10.0±1.2 mmol/mol (P<0.001). Adjusted repeated measures analysis of carbamylated albumin concentration from dialysis initiation to 1 year or death showed that the mean change (95% confidence interval) in carbamylated albumin concentration from baseline to final measure differed significantly between groups (-9.3; 95% confidence interval, -10.8 to -7.7 for controls and -6.3; 95% confidence interval, -7.7 to -2.8 for patients; P<0.01). There were no such between-group differences in blood urea levels, Kt/V, or normalized protein catabolic rate. Mortality prediction assessed using c statistics showed that carbamylated albumin concentration, when modeled continuously as the difference from baseline to final, improved a fully adjusted model from 0.76 to 0.87 (P=0.03).

CONCLUSIONS

Protein carbamylation decreased with dialysis initiation, and a greater reduction over time was associated with a lower risk for mortality. Carbamylation changes were able to predict individuals' mortality risk beyond traditional variables, including markers of dialysis adequacy and nutrition.

Functional and Cognitive Impairment, Frailty, and Adverse Health Outcomes in Older Patients Reaching ESRD-A Systematic Review

BACKGROUND AND OBJECTIVES

Older patients reaching ESRD have a higher risk of adverse health outcomes. We aimed to determine the association of functional and cognitive impairment and frailty with adverse health outcomes in patients reaching ESRD. Understanding these associations could ultimately lead to prediction models to guide tailored treatment decisions or preventive interventions.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We searched MEDLINE, Embase, Web of Science, CENTRAL, CINAHL, PsycINFO, and COCHRANE for original studies published until February 8, 2016 reporting on the association of functional or cognitive impairment or frailty with adverse health outcome after follow-up in patients reaching ESRD either with or without RRT.

RESULTS

Of 7451 identified citations, we included 30 articles that reported on 35 associations. Mean age was >60 years old in 73% of the studies, and geriatric conditions were highly prevalent. Twenty-four studies (80%) reported on functional impairment, seven (23%) reported on cognitive impairment, and four (13%) reported on frailty. Mortality was the main outcome measure in 29 studies (97%), and one study assessed functional status trajectory. In 34 of 35 (97%) associations reported, functional or cognitive impairment or frailty was significantly and independently associated with adverse health outcomes. The majority of studies (83%) were conducted in selected patient populations, mainly patients on incident dialysis.

CONCLUSIONS

Functional and cognitive impairment and frailty in patients reaching ESRD are highly prevalent and strongly and independently associated with adverse health outcomes, and they may, therefore, be useful for risk stratification. More research into their prognostic value is needed.

An association between time-varying serum albumin level and the mortality rate in maintenance haemodialysis patients: a five-year clinical cohort study

BACKGROUND

Until now, no long-term studies relating serum albumin level to mortality rate in prevalent haemodialysis (HD) patients have been conducted. We aimed to examine the association between serum albumin level and mortality over a 5-year period.

METHODS

This study included 781 patients who received maintenance HD in a large, hospital-facilitated HD centre. Five-year medical records (2009-2013) were retrospectively reviewed, and the cut-off level for serum albumin level was set at 3.5 g/dL. The analysed albumin levels were expressed as time-averaged levels (first 24-month data) and albumin target reach rate over the first 2-year interval. Univariate and multivariate Cox proportional hazard regression models were used to examine the hazard function of the all-cause and cardiovascular mortality of the study participants in the subsequent 3-year period (2011-2013).

RESULTS

Compared to those with a 100 % albumin reach rate (3.5 g/dL), the participants with 75- < 100, 50- < 75, and 1- < 50 % albumin reach rates exhibited significantly increased risk for all-cause mortality (HR 1.72, 95 % CI 1.19-2.47; HR 3.14, 95 % CI 1.91-5.16; HR 3.66, 95 % CI 2.18-6.16, respectively). A similar trend for all-cause mortality was demonstrated in participants with time-averaged albumin levels <4 g/dL (HR 1.57, 95 % CI 1.00-2.46 for 3.5-4.0 g/dL; HR 3.66, 95 % CI 2.11-6.32 for <3.5 g/dL). Compared to a 100 % albumin reach rate, the 50- < 75 and 1- < 50 % groups (HR 4.28, 95 % CI 1.82-10.01; HR 3.23, 95 % CI 1.22-8.54 respectively) showed significantly higher cardiovascular mortality rates. Similarly, participants with a time-averaged serum albumin level <3.5 g/dL exhibited a higher risk for cardiovascular mortality (HR 3.24, 95 % CI: 1.23-8.56).

CONCLUSIONS

This long-term study demonstrated that higher reach rates of serum albumin levels and higher time-averaged serum albumin levels are associated with a lower mortality rate in patients undergoing maintenance HD.