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

The Mutual Contribution of 3-NT, IL-18, Albumin, and Phosphate Foreshadows Death of Hemodialyzed Patients in a 2-Year Follow-Up

Patients with chronic kidney disease (CKD), especially those who are hemodialyzed (HD), are at significantly high risk of contracting cardiovascular disease and having increased mortality. This study aimed to find potential death predictors, the measurement of which may reflect increased mortality in HD patients, and then combine the most promising ones in frames of a simple death risk assessment model. For this purpose, HD patients (n=71) with acute myocardial infarction in the last year (HD group) and healthy people (control group) as a comparative group (n=32) were included in the study. Various laboratory determinations and non-invasive cardiovascular tests were performed. Next, patients were followed for two years, and data on cardiovascular (CV) deaths were collected. On this basis, two HD groups were formed: patients who survived (HD-A, n=51) and patients who died (HD-D, n=20). To model HD mortality, 21 out of 90 potential variables collected or calculated from the raw data were selected. The best explanatory power (95.5%) was reached by a general linear model with four variables: interleukin 18, 3-nitrotyrosine, albumin, and phosphate. The interplay between immuno-inflammatory processes, nitrosative and oxidative stress, malnutrition, and calcium-phosphate disorders has been indicated to be essential in predicting CV-related mortality in studied HD patients. ClinicalTrials.gov Identifier: NCT05214872.

Assessing Global Kidney Nutrition Care

BACKGROUND AND OBJECTIVES

Nutrition intervention is an essential component of kidney disease management. This study aimed to understand current global availability and capacity of kidney nutrition care services, interdisciplinary communication, and availability of oral nutrition supplements.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The International Society of Renal Nutrition and Metabolism (ISRNM), working in partnership with the International Society of Nephrology (ISN) Global Kidney Health Atlas Committee, developed this Global Kidney Nutrition Care Atlas. An electronic survey was administered among key kidney care stakeholders through 182 ISN-affiliated countries between July and September 2018.

RESULTS

Overall, 160 of 182 countries (88%) responded, of which 155 countries (97%) answered the survey items related to kidney nutrition care. Only 48% of the 155 countries have dietitians/renal dietitians to provide this specialized service. Dietary counseling, provided by a person trained in nutrition, was generally not available in 65% of low-/lower middle-income countries and "never" available in 23% of low-income countries. Forty-one percent of the countries did not provide formal assessment of nutrition status for kidney nutrition care. The availability of oral nutrition supplements varied globally and, mostly, were not freely available in low-/lower middle-income countries for both inpatient and outpatient settings. Dietitians and nephrologists only communicated "sometimes" on kidney nutrition care in ≥60% of countries globally.

CONCLUSIONS

This survey reveals significant gaps in global kidney nutrition care service capacity, availability, cost coverage, and deficiencies in interdisciplinary communication on kidney nutrition care delivery, especially in lower-income countries.

Executive Summary of the Korean Society of Nephrology 2021 Clinical Practice Guideline for Optimal Hemodialysis Treatment

The Korean Society of Nephrology (KSN) has published a clinical practice guideline (CPG) document for maintenance hemodialysis (HD). The document, 2021 Clinical Practice Guideline on Optimal HD Treatment, is based on an extensive evidence-oriented review of the benefits of preparation, initiation, and maintenance therapy for HD, with the participation of representative experts from the KSN under the methodologists’ support for guideline development. It was intended to help clinicians participating in HD treatment make safer and more effective clinical decisions by providing user-friendly guidelines. We hope that this CPG will be meaningful as a recommendation in practice, but not on a regulatory rule basis, as different approaches and treatments may be used by health care providers depending on the individual patient’s condition. This CPG consists of eight sections and 15 key questions. Each begins with statements that are graded by the strength of recommendations and quality of the evidence. Each statement is followed by a summary of the evidence supporting the recommendations. There is also a link to full-text documents and lists of the most important reports so that the readers can read further (most of this is available online).

Prognostic Value of the Malnutrition-inflammation Score in Hospitalization and Mortality on Long-term Hemodialysis

OBJECTIVE

Since its development, cumulative evidence has accumulated regarding the prognostic value of the Malnutrition-Inflammation Score (MIS/Kalantar score) prognostic value; however, there is a shortage of recent and large studies with comprehensive statistical methodologies that contribute to support a higher level of evidence and a consensual cutoff. The aim of this study was to assess the strength of MIS association with hospitalization and mortality in a nationwide cohort.

METHODS

This was a historical cohort study of hemodialysis patients from 25 outpatient centers followed up for 48 months. Univariable and multivariable Cox additive regression models were used to analyze the data. The C-index was estimated to assess the performance of the final model.

RESULTS

Two thousand four hundred forty-four patients were analyzed, 59.0% males, 32.0% diabetic, and median age of 71 years (P₂₅ = 60, P₇₅ = 79). During a median period of 45-month follow-up, with a maximum of 48 months (P₂₅ = 31; P₇₅ = 48), 875 patients presented an MIS <5 (35.8%) and 860 patients (35.2%) died. The proportion of deaths was 23.1% for patients with the MIS <5 and 41.9% if the MIS ≥5 (P < .001). A total of 1,528 patients (62.5%) were hospitalized with a median time to the first hospitalization of 26 months (P₂₅ = 9; P₇₅ = 45). A new cutoff point regarding the risk of death, MIS ≥6, was identified for this study data set. In multivariable analysis for hospitalization risk, a higher MIS, higher comorbidity index, and arteriovenous graft or catheter increased the risk, whereas higher Kt/V and higher albumin had a protective effect. In multivariable analysis for mortality risk, adjusting for age, albumin, normalized protein catabolic rate, Charlson comorbidity index, interdialytic weight gain, Kt/V, diabetes, hematocrit, and vascular access, patients with the MIS ≥6 showed a hazard ratio of 1.469 (95% confidence interval: 1.262-1.711; P < .001). Higher age, higher interdialytic weight gain, higher comorbidity index, and catheter increased significantly the risk, whereas higher Kt/V, higher albumin, and higher normalized protein catabolic rate (≥1.05 g/kg/d) reduced the risk.

CONCLUSION

The MIS maintains its relevant and significant association with hospitalization and mortality.

Effect of Intradialytic Supine Ergometer Exercise on Hemodialysis Patients with Different Nutritional Status

OBJECTIVE

It is important for hemodialysis patients to exercise while their nutritional status is being monitored. This study aimed to examine the difference in physical exercise function and the effect of exercise intervention in hemodialysis patients who were divided into two groups (high-nutrition and low-nutrition groups) based on the serum albumin levels.

METHOD

A total of 26 outpatients (18 men and 8 women) undergoing hemodialysis (age: 66 ± 10 years) were included in this study. The patients' body composition data (weight, body mass index, percentage of body fat, fat-free mass, and total body water) and physical functions (grip strength, knee extensor strength, open-eyed one-legged standing time, long sitting trunk anteflexion, and 6-minute walking distance [6MWD] test) were measured. The intervention was supine ergometer exercise during hemodialysis, and the patients exercised for 30 minutes during hemodialysis thrice a week. The intervention period was three months.

RESULTS

Compared to the high-nutrition group, the low-nutrition group showed a significant decrease in muscle strength. Furthermore, long sitting trunk anteflexion in the high-nutrition group and 6MWD in the low-nutrition group improved significantly after the intervention.

CONCLUSION

The result of this study may indicate that 6MD can be improved by exercise during dialysis, regardless of nutritional status. It is said that low nutritional status has a negative impact on survival rate; thus, considering the impact on survival rate, it is hemodialysis patients with a low nutritional status that should be considered to introduce more active exercise during dialysis.

Clinical relevance of abstruse transport phenomena in haemodialysis

Haemodialysis (HD) utilizes the bidirectional properties of semipermeable membranes to remove uraemic toxins from blood while simultaneously replenishing electrolytes and buffers to correct metabolic acidosis. However, the nonspecific size-dependent transport across membranes also means that certain useful plasma constituents may be removed from the patient (together with uraemic toxins), or toxic compounds, e.g. endotoxin fragments, may accompany electrolytes and buffers of the dialysis fluids into blood and elicit severe biological reactions. We describe the mechanisms and implications of these undesirable transport processes that are inherent to all HD therapies and propose approaches to mitigate the effects of such transport. We focus particularly on two undesirable events that are considered to adversely affect HD therapy and possibly impact patient outcomes. Firstly, we describe how loss of albumin (and other essential substances) can occur while striving to eliminate larger uraemic toxins during HD and why hypoalbuminemia is a clinical condition to contend with. Secondly, we describe the origins and mode of transport of biologically active substances (from dialysis fluids with bacterial contamination) into the blood compartment and biological reactions they elicit. Endotoxin fragments activate various proinflammatory pathways to increase the underlying inflammation associated with chronic kidney disease. Both phenomena involve the physical as well as chemical properties of membranes that must be selected judiciously to balance the benefits with potential risks patients may encounter, in both the short and long term.

Higher one-year achievement rate of serum phosphate associated with lower cardiovascular mortality in hemodialysis patients

Background

Estimation of phosphate load in hemodialysis patients is always controversial in clinical practice. The aim of this study was to verify individual achievement rate of serum phosphate as the evaluation of phosphate load through investigating its impact on cardiovascular mortality in hemodialysis patients.

Methods

This was a single-center, retrospective cohort study. A total of 251 maintenance hemodialysis patients were enrolled. The individual achievement rate of serum phosphate was defined as the times of tests within the target range divided by total times of tests over a period of time. Cox regression model was used to examine the relationship between individual achievement rate of serum phosphate and cardiovascular mortality.

Results

The mean age of the study population was 61 ± 13 years old. A total of 44 (17.5%) patients died from cardiovascular disease (CVD) during a median follow-up of 65 months. Multivariable Cox analysis showed that one-year serum phosphate achievement rate of 0% (HR = 4.117, P = 0.016) and 25% (HR = 3.343, P = 0.023) increased the risk of cardiovascular mortality while the achievement rate of 50% (HR = 2.129, P = 0.162) and 75% (HR = 1.080, P = 0.902) did not, compared to the rate of 100%. Urea reduction ratio (URR) was positively, while serum intact parathyroid hormone (iPTH), alkaline phosphatase (ALP), normalized protein catabolic rate (nPCR), and total phosphate-binding capacity of drug were negatively associated with achievement in target of serum phosphate.

Conclusions

Keeping one-year achievement rate of serum phosphate higher than 50% provides significant clinical benefits in reducing cardiovascular mortality.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02547-z.

Serum Albumin Trends in Relation With Prognosis of Individuals Receiving Hemodialysis Therapy

Introduction

Hypoalbuminemia is recognized as an indication of protein-energy depletion in several disease states. According to many studies, hemodialysis (HD) patients who have decreased baseline serum albumin levels exhibit a poor prognosis. However, serum albumin does not stay at a constant level with the progress of the disease, considering that only a baseline value may not precisely reflect prognostic value. The study objective was to ascertain whether there is a link between serum albumin trajectories and all-cause mortality in incident HD patients. 

Methods

Retrospective cohort analysis was conducted in the HD unit at the University of Health Sciences, Kayseri Training and Research Hospital, Nephrology Clinic between June 19, 2010, and December 29, 2017. A total of 408 individuals aged 18 years or older, who had at least one measurement of serum albumin at baseline, were enrolled. The outcome was all-cause death. Time-dependent Cox regression and joint model were used to investigate the associations between serum albumin trend in time and the risk of all-cause mortality.

Results

Mean (SD) age was 62.17 (12.33) years, and 50.7% were male. At baseline, the mean (SD) albumin level was 3.59 (0.27). A faster decrease (per 1-SD increase in negative slope) in serum albumin levels was associated with increased risk of all-cause mortality (HR, 1.63; 95% CI, 1.08-2.84; p=0.023) in a fully adjusted joint model with slope parameterization. Also, an annual 1-SD increase in albumin level declined the hazard of all-cause mortality by 22% (HR, 0.78; 95% CI, 0.66-0.92; p=0.008) in a fully adjusted joint model with value parameterization. Similar results were obtained from time-dependent Cox models.

Conclusion

These findings suggest that longitudinal albumin evaluation, including the rate of change as a slope parameter, may be valuable for risk stratification of patients receiving HD.

Changes in practice patterns in Japan from before to after JSDT 2013 guidelines on hemodialysis prescriptions: results from the JDOPPS

BACKGROUND

The Japanese Society for Dialysis Therapy (JSDT) published in 2013 inaugural hemodialysis (HD) guidelines. Specific targets include 1.4 for single-pool Kt/V (spKt/V) with a minimum dose of 1.2, minimum dialysis session length of 4 hours, minimum blood flow rate (BFR) of 200 mL/min, fluid removal rate no more than 15 mL/kg/hr, and hemodiafiltration (HDF) therapy for certain identified symptoms. We evaluated the effect of these guidelines on actual practice in the years spanning 2005 - 2018.

METHODS

Analyses were carried out to describe trends in the above HD prescription practices from December 2005 to April 2013 (before guideline publication) to August 2018 based on prevalent patient cross-sections from approximately 60 randomly selected HD facilities participating in the Japan Dialysis Outcomes and Practice Patterns Study.

RESULTS

From April 2006 to August 2017 continual rises occurred in mean spKt/V (from 1.35 to 1.49), and percent of patients having spKt/V>1.2 (71% to 85%). Mean BFR increased with time from 198.3 mL/min (April 2006) to 218.4 mL/min (August 2017) , along with percent of patients with BFR >200 ml/min (65% to 85%). HDF use increased slightly from 6% (April 2006 and August 2009) to 8% by April 2013, but increased greatly thereafter to 23% by August 2017. In contrast, mean HD treatment time showed little change from 2006-2017, whereas mean UFR declined from 11.3 in 2006 to 8.4 mL/Kg/hour in 2017.

CONCLUSIONS

From 2006 - 2018 Japanese HD patients experienced marked improvement in reaching the spKt/V target specified by the 2013 JSDT guidelines. This may have been due to moderate increase in mean BFR even though mean HD session length did not change much. In addition, HDF use increased dramatically in this time period. Other HD delivery changes during this time, such as increased use of super high flux dialyzers, also merit study. While we cannot definitively conclude a causal relationship between the publication of the guidelines and the subsequent practice changes in Japan, those changes moved practice closer to the recommendations of the guidelines.

Toward an individualized determination of dialysis adequacy: a narrative review with special emphasis on incremental hemodialysis

INTRODUCTION

The search for the 'perfect' renal replacement therapy has been paralleled by the search for the perfect biomarkers for assessing dialysis adequacy. Three main families of markers have been assessed: small molecules (prototype: urea); middle molecules (prototype β2-microglobulin); comprehensive and nutritional markers (prototype of the simplified assessment, albumin levels; composite indexes as malnutrition-inflammation score). After an era of standardization of dialysis treatment, personalized dialysis schedules are increasingly proposed, challenging the dogma of thrice-weekly hemodialysis.

AREAS COVERED

In this review, we describe the advantages and limitations of the approaches mentioned above, focusing on the open questions regarding personalized schedules and incremental hemodialysis.

EXPERT OPINION

In the era of personalized dialysis, the assessment of dialysis adequacy should be likewise personalized, due to the limits of 'one size fits all' approaches. We have tried to summarize some of the relevant issues regarding the determination of dialysis adequacy, attempting to adapt them to an elderly, highly comorbidity population, which would probably benefit from tailor-made dialysis prescriptions. While no single biomarker allows precisely tailoring the dialysis dose, we suggest using a combination of clinical and biological markers to prescribe dialysis according to comorbidity, life expectancy, residual kidney function, and small and medium-size molecule depuration.

Serum albumin and risks of hospitalization and death: Findings from the Atherosclerosis Risk in Communities study

OBJECTIVES

To determine whether lower serum albumin in community-dwelling, older adults is associated with increased risk of hospitalization and death independent of pre-existing disease.

DESIGN

Prospective cohort study of participants in the fifth visit of the Atherosclerosis Risk in Communities (ARIC) study. Baseline data were collected from 2011 to 2013. Follow-up was available to December 31, 2017. Replication was performed in Geisinger, a health system in rural Pennsylvania.

SETTING

For ARIC, four US communities: Washington County, Maryland; Forsyth County, North Carolina; Jackson, Mississippi; and suburbs of Minneapolis, Minnesota.

PARTICIPANTS

A total of 4947 community-dwelling men and women aged 66 to 90 years.

EXPOSURE

Serum albumin.

MAIN OUTCOMES

Incident all-cause hospitalization and death.

RESULTS

Among the 4947 participants, mean age was 75.5 years (SD: 5.12) and mean baseline serum albumin concentration was 4.05 g/dL (SD: 0.30). Over a median follow-up period of 4.42 years (interquartile interval: 4.16-5.05), 553 participants (11.2%) died and 2457 participants (49.7%) were hospitalized at least once. The total number of hospitalizations was 5725. In analyses adjusted for demographics and numerous clinical characteristics, including tobacco use, obesity, frailty, cardiovascular disease, kidney disease, diabetes C-reactive protein (CRP), cognitive status, alcohol use, medication use, respiratory disease, and systolic blood pressure, 1 g/dL lower baseline serum albumin concentration was associated with higher risk of both hospitalization (incidence rate ratio [IRR]: 1.58; 95% confidence interval [CI]: 1.36-1.82; p < 0.001) and death (hazard ratio [HR]: 1.67; 95% CI: 1.24-2.24; p < 0.001). Associations were weaker with older age but not different by frailty status or level of high-sensitivity CRP. Associations between serum albumin, hospitalizations, and death were also similar in a real-world cohort of primary care patients.

CONCLUSIONS

Lower baseline serum albumin was significantly associated with increased risk of both all-cause hospitalization and death, independent of pre-existing disease. Older adults with low serum albumin should be considered a high-risk population and targeted for interventions to reduce the risk of adverse outcomes.

Clinical assessment of nutritional status using the modified quantified subjective global assessment and anthropometric and biochemical parameters in patients undergoing hemodialysis in Macao

OBJECTIVE

Malnutrition is widespread among patients undergoing hemodialysis and is linked to high morbidity and mortality rates. We evaluated the nutritional status and malnutrition markers in patients undergoing hemodialysis in Macao.

METHODS

We performed a cross-sectional analysis of 360 patients in a hemodialysis center. The modified quantitative subjective global assessment (MQSGA), anthropometric indices and related biochemical test data were used to evaluate nutritional status.

RESULTS

The sample's mean age was 63.47 ± 13.95 years. There were 210 well-nourished (58.3%), 139 mild-to-moderately malnourished (38.6%) and 11 severely malnourished (3.1%) patients. Older patients had a higher incidence of severe malnutrition, but there were no significant differences between diabetic and non-diabetic patients. Mid-arm circumference (MAC); mid-arm muscle circumference; body mass index; triceps skin fold thickness; serum albumin, creatinine and urea; and hemoglobin were all valid for assessing nutritional status. MAC and the serum albumin and creatinine concentrations significantly negatively correlated with MQSGA.

CONCLUSIONS

Malnutrition is commonplace in patients undergoing hemodialysis in Macao, but their nutritional status is not affected by diabetes. Serum creatinine, serum albumin and MAC, and especially pre-dialysis creatinine concentration, represent effective, readily available, and easily remembered screening measures of nutritional status for patients undergoing maintenance dialysis.

Comparison of two regional citrate anticoagulation modalities for continuous renal replacement therapy by a prospective analysis of safety, workload, effectiveness, and cost

BACKGROUND

Currently, regional citrate anticoagulation (RCA) is the preferred approach for continuous renal replacement therapy (CRRT), and several RCA protocols are commercially available. This study was aimed at comparing two RCA modalities for CRRT in terms of safety, workload, effectiveness, and costs.

METHODS

We prospectively evaluated two different RCA approaches in patients admitted to our intensive care unit (ICU) who needed CRRT. Patients with acute liver failure were excluded. We compared a hypertonic sodium-citrate solution 136 mmol/L added before the filter as anticoagulant during bicarbonate continuous hemodialysis (RCA-CVVHD) versus citrate-buffered replacement fluid 13.3 mmol/L infused by predilution setting in continuous venovenous hemofiltration (RCA-CVVH). Alkalosis, calcium homeostasis, nursing workload, filter lifespan, urea-creatinine metabolic control, and costs were recorded.

RESULTS

Forty-five and 31 patients who underwent RCA-CVVH and RCA-CVVHD, respectively, were included. Alkalosis-free time distributions were significantly different in favor of a higher alkalosis incidence in the RCA-CVVHD group (log-rank test χ²(1)=8.18, P=0.004). Multivariable analysis showed that RCA-CVVHD was associated with a longer filter lifespan (HR=0.47; 95% CI: 0.28-0.78), higher total cost (1362 CHF [782-1901] vs. 976 CHF [671-1353], P<0.001), and higher number of anticoagulation adjustments (9 [IQR, 4-14] vs. 2 [IQR, 1-4]). The mean urea and creatinine reduction ratios at the first 24 hours were significantly higher in the RCA-CVVHD group. Calcium homeostasis and filter downtime were similar in the two groups.

CONCLUSIONS

Pre-filter hypertonic sodium-citrate solution (136 mmol/L) results in longer filter patency and improves depuration effectiveness. However, compared to RCA-CVVHF, it causes metabolic alkalosis and increases nursing interventions and cost.

Monitoring dialysis adequacy: history and current practice

Dialysis adequacy for pediatric patients has largely followed the trends in adult dialysis by judging the success or adequacy of peritoneal or hemodialysis with urea kinetic modeling. While this provides a starting point to establish a dose of dialysis, it is clear that urea is only part of the picture. Many clinical parameters and interventions now have been identified that are just as impactful on mortality and morbidly as urea clearance. As such, our concept of adequacy is evolving to include non-urea parameters and assessing the impact that following an "adequate therapy" has on patient lives. As we move to a new era, we consider the impact these therapies have on patients and how it affects the quality of their lives; we must take these factors into consideration to achieve a therapy that is not just adequate, but livable.

Novel and Simple Criteria for Predicting Mortality of Peptic Ulcer Disease

Objective Conventional risk scores of peptic ulcer disease (PUD) are based on many parameters, and their application in clinical practice is therefore limited. The aim of this study was to establish simple and reliable criteria for predicting PUD-associated mortality. Methods A total of 499 patients with PUD were divided into 2 groups: the training cohort (n=333) and the validation cohort (n=166). To minimize selection bias due to missing values, we used imputed datasets generated by the multiple imputation method (training-cohort dataset, n=33,300; validation-cohort dataset, n=16,600). Results In the training-cohort dataset, the heart rate-to-systolic blood pressure ratio (HR/SBP) and serum albumin (s-Alb) level were significant independent predictive factors for mortality according to the multivariate analysis [HR/SBP, odds ratio (OR): 1.72; 95% confidence interval (CI), 1.06-2.80, p=0.028; s-Alb, OR: 0.23, 95% CI, 0.11-0.51, p<0.001]. The model comprising HR/SBP and s-Alb was able to detect mortality due to PUD with an area under the curve (AUC) of 0.855. In the validation-cohort dataset, this model also showed good efficacy with an AUC of 0.835. The novel criteria combining HR/SBP and s-Alb developed by a decision tree analysis showed 73.3% sensitivity and 87.6% specificity for predicting mortality in the total-cohort dataset. Our criteria were superior to the Glasgow Blatchford and Rockall scores and similar to the AIMS65 and Progetto Nazionale Emorragia Digestiva scores for predicting mortality. Conclusion The combination of the HR/SBP ratio and s-Alb level is a good predictor of mortality in patients with PUD.

Dialysis adequacy predictions using a machine learning method

Dialysis adequacy is an important survival indicator in patients with chronic hemodialysis. However, there are inconveniences and disadvantages to measuring dialysis adequacy by blood samples. This study used machine learning models to predict dialysis adequacy in chronic hemodialysis patients using repeatedly measured data during hemodialysis. This study included 1333 hemodialysis sessions corresponding to the monthly examination dates of 61 patients. Patient demographics and clinical parameters were continuously measured from the hemodialysis machine; 240 measurements were collected from each hemodialysis session. Machine learning models (random forest and extreme gradient boosting [XGBoost]) and deep learning models (convolutional neural network and gated recurrent unit) were compared with multivariable linear regression models. The mean absolute percentage error (MAPE), root mean square error (RMSE), and Spearman's rank correlation coefficient (Corr) for each model using fivefold cross-validation were calculated as performance measurements. The XGBoost model had the best performance among all methods (MAPE = 2.500; RMSE = 2.906; Corr = 0.873). The deep learning models with convolutional neural network (MAPE = 2.835; RMSE = 3.125; Corr = 0.833) and gated recurrent unit (MAPE = 2.974; RMSE = 3.230; Corr = 0.824) had similar performances. The linear regression models had the lowest performance (MAPE = 3.284; RMSE = 3.586; Corr = 0.770) compared with other models. Machine learning methods can accurately infer hemodialysis adequacy using continuously measured data from hemodialysis machines.

Effect of intestinal dialysis using polyethylene glycol on fluid balance and thirst in maintenance hemodialysis patients: A comparative study

High inter-dialytic weight gains (IDWG) and Hyperkalemia have been associated with adverse outcomes like poor quality of life and high mortality. Thirst remains an unsolved problem in hemodialysis (HD) patients. The aim of this study was to evaluate the effect of polyethylene glycol (PEG) based intestinal dialysis on IDWG, thirst and biochemical parameters. A prospective interventional evidenced based paired comparative single center study was conducted. Thirty-five anuric patients on weekly thrice HD were studied for four consecutive dialysis weeks. Before the mid-week dialysis day of week 3, Patients received 2 L PEG solution. The primary end points were change in mean relative IDWG and change in mean subjective thirst feeling as measured on visual analog scale (VAS) with secondary endpoints being change in small molecule clearance. There was significant reduction in IDWG after the therapy from 3 ± 0.81 L to 2.35 ± 0.72 (P = 0.002). The therapy also reduced the % IDWG BW from 5.1 ± 1.7% to 4.15 ± 1.6% (P = 0.017). No change in thirst was seen, that is, 6.16 ± 0.66, 6.14 ± 0.64, and 6.16 ± 0.65 (P = 0.986). A multivariate linear regression did not reveal any effect of age, gender, and co-morbidities on the reduction of IDWG and thirst. The therapy achieved a significant urea, creatinine, and potassium reduction of 8.23%, 8.13%, and 8.33% respectively with an increase in sodium levels by 0.86%. This modality reduced the IDWG, was found to be a potent treatment modality for hyperkalemia but did not affect thirst sensation even after consumption of 2 L solution.

Dialysis dose and mortality in hemodialysis: Is higher better?

BACKGROUND

The effect of dialysis dose on mortality remains unsettled. Current guidelines recommend to target a spKt/V at 1.20 to 1.40 per tri-weekly dialysis session. However, the optimal dialysis dose remains mostly disputed.

METHODS

In a nationwide registry of all incident patients receiving thrice-weekly hemodialysis, 32 283 patients had available data on dialysis dose, estimated by Kt/V and its variants Kt and Kt/A. Survival was analyzed with a multivariate Cox model and a concurrent risk model accounting for renal transplantation. A predictive model of Kt in the upper quartile was developed.

RESULTS

Regardless of the indicator, a higher dose of dialysis was consistently associated with better survival. The survival differential of Kt was the most discriminating, but marginally, compared to the survival differential according to Kt/V and Kt/A. Patient survival was higher in the upper quartile of Kt (> 69L/s), then deteriorated as the Kt decreased with a difference in survival between the upper and lower quartile of 23.6% at five years. Survival differences across Kt distribution were similar after accounting for kidney transplantation as a competing risk. Predictive factors for Kt in the upper quartile were arteriovenous fistula versus catheters and graft, hemodiafiltration versus hemodialysis, scheduled dialysis start versus emergency start, long weekly dialysis duration, spKt/V measurement versus double pool eKt/V.

CONCLUSION

Our data confirm the existence of a relationship between dialysis dose and survival, which persisted despite correcting for known confounders. A model for predicting a high dose of dialysis is proposed with practical relevance.

Genetically determined hypoalbuminemia as a risk factor for hypertension: instrumental variable analysis

Hypoalbuminemia is associated with vascular endothelial dysfunction and the development of chronic cardiovascular diseases. However, the relationship between serum albumin concentration and blood pressure changes remains controversial. Community-based longitudinal cohort data collected from Korean Genome and Epidemiology Study were used in this study. Hypoalbuminemia was defined as a serum albumin concentration of ≤ 4.0 g/dL. A total of 4325 participants were categorized into control (n = 3157) and hypoalbuminemia (n = 1168) groups. Serum albumin had a non-linear relationship with the risk of hypertension development. A genome-wide association study revealed 71 susceptibility loci associated with hypoalbuminemia. Among susceptibility loci, genetic variations at rs2894536 in LOC107986598 and rs10972486 in ATP8B5P were related to elevated blood pressure. Serum albumin (HR = 0.654, 95% CI 0.521-0.820) and polymorphisms of rs2894536 (HR = 1.176, 95% CI 1.015-1.361) and rs10972486 (HR = 1.152, 95% CI 1.009-1.316) were significant predictors of hypertension development. Increased albumin concentration instrumented by 2 hypoalbuminemia-associated SNPs (rs2894536 and rs10972486) was associated with decreased HRs for hypertension development (HR = 0.762, 95% CI 0.659-0.882 and HR = 0.759, 95% CI 0.656-0.878). Our study demonstrated that genetically determined hypoalbuminemia is a significant predictor of incipient hypertension.

Intravenous Albumin for Mitigating Hypotension and Augmenting Ultrafiltration during Kidney Replacement Therapy

Among its many functions, owing to its oversized effect on colloid oncotic pressure, intravascular albumin helps preserve the effective circulatory volume. Hypoalbuminemia is common in hospitalized patients and is found especially frequently in patients who require KRT either for AKI or as maintenance hemodialysis. In such patients, hypoalbuminemia is strongly associated with morbidity, intradialytic hypotension, and mortality. Intravenous albumin may be administered in an effort to prevent or treat hypotension or to augment fluid removal, but this practice is controversial. Theoretically, intravenous albumin administration might prevent or treat hypotension by promoting plasma refilling in response to ultrafiltration. However, clinical trials have demonstrated that albumin administration is not nearly as effective a volume expander as might be assumed according to its oncotic properties. Although intravenous albumin is generally considered to be safe, it is also very expensive. In addition, there are potential risks to using it to prevent or treat intradialytic hypotension. Some recent studies have suggested that hyperoncotic albumin solutions may precipitate or worsen AKI in patients with sepsis or shock; however, the overall evidence supporting this effect is weak. In this review, we explore the theoretical benefits and risks of using intravenous albumin to mitigate intradialytic hypotension and/or enhance ultrafiltration and summarize the current evidence relating to this practice. This includes studies relevant to its use in patients on maintenance hemodialysis and critically ill patients with AKI who require KRT in the intensive care unit. Despite evidence of its frequent use and high costs, at present, there are minimal data that support the routine use of intravenous albumin during KRT. As such, adequately powered trials to evaluate the efficacy of intravenous albumin in this setting are clearly needed.

Laboratory correlates of SARS-CoV-2 seropositivity in a nationwide sample of patients on dialysis in the U.S

Patients on dialysis are at high risk for death due to COVID-19, yet a significant proportion do survive as evidenced by presence of SARS-CoV-2 antibodies in 8% of patients in the U.S. in July 2020. It is unclear whether patients with seropositivity represent the subgroup with robust health status, who would be more likely to mount a durable antibody response. Using data from a July 2020 sample of 28,503 patients receiving dialysis, we evaluated the cross-sectional association of SARS-CoV-2 seropositivity with laboratory surrogates of patient health. In separate logistic regression models, we assessed the association of SARS-CoV-2 seropositivity with seven laboratory-based covariates (albumin, creatinine, hemoglobin, sodium, potassium, phosphate, and parathyroid hormone), across the entire range of the laboratory and in comparison to a referent value. Models accounted for age, sex, region, race and ethnicity, and county-level COVID-19 deaths per 100,000. Odds of seropositivity for albumin 3 and 3.5 g/dL were 2.1 (95% CI 1.9-2.3) and 1.3 (1.2-1.4) respectively, compared with 4 g/dL. Odds of seropositivity for serum creatinine 5 and 8 mg/dL were 1.8 (1.6-2.0) and 1.3 (1.2-1.4) respectively, compared with 12.5 mg/dL. Lower values of hemoglobin, sodium, potassium, phosphate, and parathyroid hormone were associated with higher odds of seropositivity. Laboratory values associated with poorer health status and higher risk for mortality were also associated with higher likelihood of SARS-CoV-2 antibodies in patients receiving dialysis.

Analyzing clinical characteristics of patients with different cumulative hemodialysis durations: a cross-sectional study

Background

The objective of this study was to examine the clinical characteristics of patients with different cumulative hemodialysis (HD) durations, so as to improve their survival rate.

Methods

In this cross-sectional study, we extracted background information and relevant clinical data from 145 patients who were undergoing maintenance HD three times a week at the Affiliated Hospital of Nantong University between January 1998 and January 2019. The study subjects were divided into four groups according to the duration of their HD: <5 years, 5–10 years, 10–15 years, and >15 years of HD. We collected the medical history and relevant clinical parameters for each subject, and measured the urea reduction ratio (URR), hemoglobin (Hb), serum calcium, phosphorus, parathyroid hormone (iPTH), and serum albumin (ALB) levels for each group.

Results

The average patient age was 52.06 ±  11.93 years old. The average patient age in the 10–15 years and >15 years groups was significantly lower than in the <5 years and 5–10 years groups (P = 0.002, P < 0.001, P = 0.012, and P = 0.0025, respectively). The most common cause of end-stage renal disease (ESRD) was chronic glomerulonephritis. We found no significant differences in URR, Hb, serum calcium, serum phosphorus, iPTH, and ALB levels.

Conclusion

A prolonged HD duration was related to a younger mean age at the start of HD treatment. The leading cause of ESRD was chronic glomerulonephritis. We predominantly found diabetic nephropathy in the group with a duration of <5 years cumulative HD. Most of the indexes related to hemodialysis almost satisfied the recommended values in these patients.

The Nitty-Gritties of Kt/Vurea Calculations in Hemodialysis and Peritoneal Dialysis

In advanced Chronic Kidney Disease, patients require renal replacement therapy (dialysis or transplantation) for clearance of toxins, electrolyte and acid-base balance and removal of excess fluid. Dialysis adequacy should be taken into consideration in the adjustment of the dialysis prescription. Kt/Vurea is one method of measuring dialysis adequacy that is commonly used in clinical practice. Different formulae for calculating Kt/V are available. The appropriate Kt/V formula to be used depends on the clinical scenario, as well as parameters such as gender and size of patient, frequency of dialysis, mode of dialysis (ie hemodialysis vs, peritoneal dialysis), inter-dialysis weight gain, clinical symptoms, complications (fluid overload, hyperkalemia, intolerance to dialysis, etc), and residual kidney function. Nutrition parameters including serum protein and albumin levels, vitamin B12 and β2-microglobulin levels should be factored into the assessment of dialysis adequacy. In this review, we have described how Kt/Vurea is calculated in hemodialysis and peritoneal dialysis with examples. We reviewed the available literature by searching for papers related to calculating Kt/Vurea, single pool Kt/V, double pool Kt/V, weekly Kt/V, standard Kt/V, surface area normalized Kt/V, and various equations commonly practiced in clinical practice. We found several original articles, some review articles along with detailed information from manufacturers of different dialyzers published on their websites or as package inserts. Understanding the different equations available for calculating Kt/Vurea and the application of these results in the clinical setting is important for refining patient care and for designing clinical studies.

Slipping Through the Pores: Hypoalbuminemia and Albumin Loss During Hemodialysis

Hypoalbuminemia results when compensatory mechanisms are unable to keep pace with derangements in catabolism/loss and/or decreased synthesis of albumin. Across many disease states, including chronic kidney disease (CKD), hypoalbuminemia is a well-established, independent risk factor for adverse outcomes, including mortality. In the setting of CKD, reduced serum albumin concentrations are often a manifestation of protein-energy wasting, a state of metabolic and nutritional alterations resulting in reduced protein and energy stores. The progression of CKD to kidney failure and the initiation of maintenance hemodialysis (HD) further predisposes an already at-risk population toward hypoalbuminemia such that approximately 60% of HD patients have albumin concentrations <4.0 g/dl. Albumin loss into the dialysate through the dialyzer appears to be a potentially modifiable cause of hypoalbuminemia in some patients. A group of newer dialyzers for maintenance HD-sometimes termed protein-leaking or medium cut-off membranes-aim to improve clearance of middle molecules (vs high flux dialyzers) but are associated with increased albumin losses. In this article, we will examine the impact of dialyzer selection on albumin losses during conventional HD, including the clinical relevance of such losses on serum albumin levels. Data on the clinical relevance of albumin losses during dialysis and current gaps in the evidence base are also discussed.

Measurement of serum albumin in nephrology: we need to improve

Serum albumin is a widely used biomarker in clinical nephrology. Serum albumin cut-off values are used to define disease, to predict outcome, and to guide patient care. The available commercial assays to measure serum albumin rely on different analytical principles, all with their own (analytical) specifications. This paper provides an overview of the different clinical applications of serum albumin measurements in nephrology, the (dis)advantages of the available assays and the estimates of the effects of the measurement uncertainty between different assays in clinical decision making. This paper concludes that harmonisation of serum albumin assay results are needed.

Emergent initiation of dialysis is related to an increase in both mortality and medical costs

The number of patients with end-stage renal disease (ESRD) has been increasing, with dialysis treatment being a serious economic problem. To date, no report in Japan considered medical costs spent at the initiation of dialysis treatment, although some reports in other countries described high medical costs in the first year. This study focused on patient status at the time of initiation of dialysis and examined how it affects prognosis and the medical costs. As a result, all patients dying within 4 months experienced emergent dialysis initiation. Emergent dialysis initiation and high medical costs were risk factors for death within 2 years. High C-reactive protein levels and emergent dialysis initiation were associated with increasing medical costs. Acute kidney injury (AKI) contributed most to emergent dialysis initiation followed by stroke, diabetes, heart failure, and short-term care by nephrologists. Therefore, emergent dialysis initiation was a contributing factor to both death and increasing medical costs. To avoid the requirement for emergent dialysis initiation, patients with ESRD should be referred to nephrologists earlier. Furthermore, ESRD patients with clinical histories of AKI, stroke, diabetes, or heart failure should be observed carefully and provided pre-planned initiation of dialysis.

The association of standard Kt/V and surface area-normalized standard Kt/V with clinical outcomes in hemodialysis patients

INTRODUCTION

A previous study demonstrated that the surface area-normalized standard Kt/V (SAstdKt/V) was better associated with mortality than standard Kt/V (stdKt/V). This study investigates the association of SAstdKt/V and stdKt/V with mortality, anemia, and hypoalbuminemia in a larger patient cohort with a longer follow-up period.

METHODS

We included adult patients on thrice-weekly hemodialysis in the USRDS database and excluded amputated patients. StdKt/V and SAstdKt/V were calculated from the available single-pool Kt/V. Patients were categorized into five groups according to their stdKt/V and SAstdKt/V: <2.00, 2.00-2.19, 2.20-2.39, 2.40-2.59, and ≥2.60. Hazard ratios (HR) and odds ratios (OR) were calculated using Cox and logistic regression analysis respectively.

FINDINGS

There were 507,656 patients included in the analysis. The patients had a median age of 65.5 years with a median follow-up period of 2 years. Thirty-four percent died during follow-up. HRs for mortality progressively decreased as SAstdKt/V increased in both unadjusted and adjusted models. Unlike SAstdKt/V, HRs were the lowest in the categories with stdKt/V of 2.40-2.59 and they increased in the higher stdKt/V category. The adjusted HR for SAstdKt/V vs. stdKt/V were 0.68 vs. 0.62 in the category of 2.40-2.59, and 0.63 vs. 0.73 in the category of ≥2.60. The adjusted ORs for anemia progressively decreased as SAstdKt/V increased, whereas ORs decreased to the lowest in stdKt/V category 2.40-2.59 and increased in the ≥2.60 category. The adjusted ORs for hypoalbuminemia progressively decreased as SAstdKt/V and stdKt/V increased which were both 0.45 in 2.40-2.59 category and decreased to 0.29 and 0.42 in the ≥2.60 category.

DISCUSSION

SAstdKt/V is better associated with mortality, anemia, and hypoalbuminemia than stdKt/V. SAstdKt/V is a better parameter in defining hemodialysis dosing which can be calculated by an available online tool. Further studies to determine the optimal SAstdKt/V dose required to achieve improved clinical outcomes with better cost-effectiveness are needed.

Uremic Toxins Affect Erythropoiesis during the Course of Chronic Kidney Disease: A Review

Chronic kidney disease (CKD) is a global health problem characterized by progressive kidney failure due to uremic toxicity and the complications that arise from it. Anemia consecutive to CKD is one of its most common complications affecting nearly all patients with end-stage renal disease. Anemia is a potential cause of cardiovascular disease, faster deterioration of renal failure and mortality. Erythropoietin (produced by the kidney) and iron (provided from recycled senescent red cells) deficiencies are the main reasons that contribute to CKD-associated anemia. Indeed, accumulation of uremic toxins in blood impairs erythropoietin synthesis, compromising the growth and differentiation of red blood cells in the bone marrow, leading to a subsequent impairment of erythropoiesis. In this review, we mainly focus on the most representative uremic toxins and their effects on the molecular mechanisms underlying anemia of CKD that have been studied so far. Understanding molecular mechanisms leading to anemia due to uremic toxins could lead to the development of new treatments that will specifically target the pathophysiologic processes of anemia consecutive to CKD, such as the newly marketed erythropoiesis-stimulating agents.

Alterations of Spontaneous Brain Activity in Hemodialysis Patients

Cognitive impairment is prevalent in hemodialysis end-stage renal disease (ESRD) patients. It might be associated with poor prognosis. Nevertheless, the underlying mechanisms have not been completely clarified. This study explored spontaneous brain activity in ESRD patients on hemodialysis by using the amplitude of low-frequency fluctuation (ALFF). Nineteen ESRD patients on regular hemodialysis were included in this study. Eighteen age-, sex- and education level-matched volunteers were enrolled as the healthy control group. All participants had resting-state functional MRI scanning, neuropsychological tests, and laboratory testing. ALFF was used for assessing intrinsic brain activity. Independent samples t-test was used for obtaining group differences. Spearman correlation analysis was applied to assess the association between ALFF changes, neuropsychological, and clinical indices. Compared to the healthy control group, hemodialysis patients showed decreased ALFF in the precuneus, right angular gyrus/inferior lobule as well as increased ALFF in the left parahippocampus/hippocampus and right precentral/postcentral gyrus. The ALFF abnormalities in these regions were closely associated with hemoglobin levels. Also, increased ALFF in the left parahippocampus/hippocampus showed a negative correlation with the score of long-delayed free recall. Hemodialysis patients had aberrant ALFF in the default mode network (DMN) regions, particularly in the precuneus and parahippocampus/hippocampus, which may be correlated with neuropathological mechanisms involved in hemodialysis.

Sustained low-efficiency dialysis with regional citrate anticoagulation for patients with liver impairment in intensive care unit: A single-center experience

Regional citrate anticoagulation (RCA) is a recommended method for extracorporeal circuit anticoagulation during renal replacement therapy (RRT). Increased risk of citrate accumulation by default of hepatic metabolism limits its use in liver failure patients. A Ca_tot /Ca_ion ratio ≥2.5 is established as an indirect control of plasma citrate poisoning. To investigate the safety of RCA in patients with liver impairment during sustained low-efficiency dialysis (SLED), we conducted a retrospective study of 41 patients with acute or chronic hepatocellular failure requiring RRT between January 2014 and June 2015 in the intensive care unit of the Groupe Hospitalier Sud Ile de France. Sixty-seven SLED sessions were performed. At admission, 32 (78%) patients had acute liver dysfunction and nine (22%) patients had cirrhosis with a median MELD score of 27 (IQR: 18.8, 42.0). Despite a majority of poor prognosis patients (SAPS-II (Simplified Acute Physiology Score II) score 71 [IQR: 58; 87]), with acute liver impairment as a part of multi-organ failure, no dosage of Ca_tot /Ca_ion ratio after SLED sessions exceeded the critical threshold of 2.5. Of the 63 complete sessions, neither dyscalcemia nor major dysnatremia, nor extracorporeal circuit thrombosis were noticed. Observed acid-base disturbances (16.4%) were not significantly correlated with the Ca_tot /Ca_ion ratio (P = .2155). In this retrospective study using RCA during intermittent RRT in ICU patients with severe liver dysfunction, we did not observe any citrate accumulation but monitoring of acid-base status and electrolytes remains necessary to ensure technique safety.

The Relationship between Dialysis Metrics and Patient-Reported Cognition, Fatigue, and Physical Function

Introduction

The impact of achieving hemodialysis laboratory and hemodynamic quality metrics on patient-reported outcomes (PROs) is unknown.

Objective

To determine if meeting dialysis laboratory quality of care measures is associated with improved PROs.

Methods

In this cross-sectional study, we measured the relationship between dialysis patients' Patient Reported Outcome Measurement Information System (PROMIS) scores and commonly used dialysis quality of care measures.

Results

PROMIS surveys were administered to 92 dialysis patients. The mean ± SD scores demonstrated higher fatigue (55.0 ± 9.8) and lower physical function (37.9 ± 7.9) but similar cognition (50.3 ± 10.9) compared to general population normative scores of 50 ± 10. Dialysis patients meeting Kt/V goals had no better scores than those who did not. Meeting the hemoglobin (Hgb) value of ≥10 g/dL was associated with a lower fatigue score, but no difference in cognitive or physical function scores. Meeting the serum albumin goal of ≥4.0 mg/dL was associated with a higher physical function score but made no difference for cognitive function or fatigue score. As a continuous variable, a higher Hgb was associated with lower reported fatigue (HR -1.74 95%, CI [-3.09, -0.39]), but no other measures were associated with PRO scores when adjusted for demographics and comorbidities.

Conclusions

We found little association between measures currently used to assess the quality of dialysis care and PROs. Encouraging improved utilization of PROs and incorporating PROs into quality measurements might give a more robust assessment of quality of care. Future studies should assess the benefits of this approach.

Meeting Treatment Goals in Patients on Extramural Dialysis in Health Social Security in Mexico

INTRODUCTION

For the majority of renal replacement therapy history, the main treatment option for patients with end-stage renal disease (ESRD) in Mexico has been peritoneal dialysis. However, the use of hemodialysis is overwhelmingly increasing, driving public health care institutions to subrogate this service. Even when the actual hiring model for subrogation is accurate, there is a lack of quality control points in the hemodialysis prescription, poor adherence to clinical practice guidelines, and a few or no record of outcomes in hemodialysis patients of these subrogated services. The objective of this work is to fill this information gap to allow for uniform and safe hemodialysis for patients of Mexico.

MATERIAL AND METHODS

An observational and cross-sectional study was performed, including all patients receiving chronic hemodialysis treatment in subrogated units of Mexican Social Security Institute (IMSS) in the northern region of Mexico City. Clinical and biochemical data as well as hemodialysis dose by Kt/V and urea reduction rate were collected and evaluated. To determine distribution, mean or median and SD or interquartile range were used; for nominal variables, the difference in proportions was estimated using the χ2 test; proportions were analyzed for biochemical values using the statistical package SPSS version 25.

RESULTS

In our study, >60% (485) of the patients were anemic with an average hemoglobin of 9.39 mg/dL (SD ± 1.83); serum calcium was found below 8.4 mg/dL in 51.3% (383) of patients, and only in 45.8% (342) was at an optimal level of this parameter. Only 33.5% of patients have arteriovenous fistula for dialysis access. The hemodialysis dose was optimal in >75% of patients.

CONCLUSIONS

It is necessary to enhance and monitor treatment of comorbidities in patients with ESRD in subrogated hemodialysis units in México. We observed adequate prescription of hemodialysis in a majority of patients, achieving quality control points for removal of nitrogen products. Yet, there is a lack of quality control of comorbidities; therefore, we should aim to optimize treatment for mineral-bone disorder, anemia, and nutritional status.

Nutritional Status in Peritoneal Dialysis: Nutritional Guidelines, Adequacy and the Management of Malnutrition

The positive impact of nutritional status on the health and treatment adequacy of peritoneal dialyzed patients has been well established. Protein intake is an important factor used to stratify malnutrition, with inadequate intake leading to protein-energy wasting during the course of therapy. In this review, we discuss the recommendations made by nephrological societies regarding nutrition in this population of dialysis patients. Special attention is given to the intake of protein, and recommendations on the intake of micronutrients are also discussed. Furthermore, factors that may impair nutritional intake and balance are discussed, with mention of the innovative strategies utilized to combat them. In light of inconsistent recommendations that vary between each respective society, as well as a general lack of concise information, it is our intention to call for further research regarding nutritional recommendations in peritoneal dialysis (PD), as well as to advocate for clear and accessible information for patients.

Gait speed and handgrip strength as predictors of all-cause mortality and cardiovascular events in hemodialysis patients

Background

Low physical performance in patients undergoing maintenance hemodialysis is associated with a high mortality rate. We investigated the clinical relevance of gait speed and handgrip strength, the two most commonly used methods of assessing physical performance.

Methods

We obtained data regarding gait speed and handgrip strength from 277 hemodialysis patients and evaluated their relationships with baseline parameters, mental health, plasma inflammatory markers, and major adverse clinical outcomes. Low physical performance was defined by the recommendations suggested by the Asian Working Group on Sarcopenia.

Results

The prevalence of low gait speed and handgrip strength was 28.2 and 44.8%, respectively. Old age, low serum albumin levels, high comorbidity index score, and impaired cognitive functions were associated with low physical performance. Patients with isolated low gait speed exhibited a general trend for worse quality of life than those with isolated low handgrip strength. Gait speed and handgrip strength showed very weak correlations with different determining factors (older age, the presence of diabetes, and lower serum albumin level for low gait speed, and lower body mass index and the presence of previous cardiovascular events for low handgrip strength). Patients with low gait speed and handgrip strength had elevated levels of plasma endocan and matrix metalloproteinase-7 and the highest risks for all-cause mortality and cardiovascular events among the groups (adjusted hazard ratio of 2.72, p = 0.024). Elderly patients with low gait speed and handgrip strength were at the highest risk for poor clinical outcomes.

Conclusion

Gait speed and handgrip strength reflected distinctive aspects of patient characteristics and the use of both factors improved the prediction of adverse clinical outcomes in hemodialysis patients. Gait speed seems to be a better indicator of poor patient outcomes than is handgrip strength.

Hypoalbuminemia: a price worth paying for improved dialytic removal of middle-molecular-weight uremic toxins?

Hemodiafiltration (HDF) increases the removal of middle-molecular-weight uremic toxins and may improve outcomes in patients with end-stage kidney disease (ESKD), but it requires complex equipment and comes with risks associated with infusion of large volumes of substitution solution. New high-flux hemodialysis membranes with improved diffusive permeability profiles do not have these limitations and offer an attractive alternative to HDF. However, both strategies are associated with increased albumin loss into the dialysate, raising concerns about the potential for decreased serum albumin concentrations that have been associated with poor outcomes in ESKD. Many factors can contribute to hypoalbuminemia in ESKD, including protein energy wasting, inflammation, volume expansion, renal loss and loss into the dialysate; of these factors, loss into the dialysate is not necessarily the most important. Furthermore, recent studies suggest that mild hypoalbuminemia per se is not an independent predictor of increased mortality in dialysis patients, but in combination with inflammation it is a poor prognostic sign. Thus, whether hypoalbuminemia predisposes to increased morbidity and mortality may depend on the presence or absence of inflammation. In this review we summarize recent findings on the role of dialysate losses in hypoalbuminemia and the importance of concomitant inflammation on outcomes in patients with ESKD. Based on these findings, we discuss whether hypoalbuminemia may be a price worth paying for increased dialytic removal of middle-molecular-weight uremic toxins.

Serum albumin is incrementally associated with increased mortality across varying levels of kidney function

OBJECTIVES

Serum albumin (sAlb) may be a strong predictor of longevity in the general population and in chronic kidney disease. This study aimed to determine the relationship between sAlb concentrations and mortality risk independent of kidney function.

METHODS

This was a retrospective cohort study of 31 274 adults from the 1999-2010 National Health and Nutrition Examination Survey. The estimated glomerular filtration rate (eGFR) was examined as both a confounder and modifier of the association of sAlb with mortality risk. We examined the association of sAlb (categorized as <3.8, 3.8 to <4.0, 4.0 to <4.2, 4.2 to <4.4, 4.4 to <4.6, 4.6 to <4.8, and ≥4.8 g/dL) with mortality using Cox models. Subsequently, we conducted spline analyses to estimate the association of sAlb with all-cause mortality across varying eGFR levels.

RESULTS

In unadjusted analyses, participants with incrementally lower sAlb concentrations of <4.6 g/dL had an increasingly higher mortality risk compared with those with sAlb levels ranging from 4.6 to <4.8 g/dL (reference), whereas those with higher sAlb levels of ≥4.8 g/dL had a lower mortality risk (hazard ratios [95% confidence interval]: 3.88 [3.26-4.62], 3.59 [3.01-4.27], 2.79 [2.37-3.29], 2.10 [1.79-2.48], 1.72 [1.45-2.03], and 0.71 [0.55-0.92] for sAlb concentrations of <3.8, 3.8 to <4.0, 4.0 to <4.2, 4.2 to <4.4, 4.4 to <4.6, and ≥4.8 g/dL, respectively). Adjusted analyses showed similar findings, although the association of higher sAlb levels of ≥4.8 g/dL with better survival was attenuated to the null. Spline analyses showed that participants with sAlb levels of <4.6 g/dL had higher mortality across all concentrations of eGFR, ranging from 30 to 120 mL/min/1.73 m² (reference: sAlb ≥ 4.6 g/dL).

CONCLUSIONS

Among a nationally representative U.S. cohort, a graded association was observed between lower sAlb concentrations and higher death risk, which was robust across varying levels of kidney function.

Oxidative Metabolism of Polymorphonuclear Leukocytes in Continuous Ambulatory Peritoneal Dialysis

Objective

To evaluate the oxidative metabolism of polymorphonuclear leukocytes (PMNL) in continuous ambulatory peritoneal dialysis (CAPD) patients compared with those of hemodialysis (HD) patients, chronic renal failure (CRF) patients not yet on dialysis, and healthy controls; and to discover factors contributing to the oxidative function in CAPD patients.

Patients

Thirty-five CAPD, 22 HD, 11 CRF patients were assessed; all were free from infections at the time of examination. Thirty-one healthy volunteers served as controls.

Methods

The oxidative metabolism was estimated by the production of superoxide anion, which was detected by luminol-dependent zymosan stimulated chemiluminescence (CL) with whole blood assessment. The volume of superoxide production equivalent to 1 mL of circulating blood (T-CL), that equivalent to 104 neutrophils (CL/N) and the velocity of superoxide production (V-CL), were measured as parameters for the oxidative function of PMNL.

Results

There were no differences in all CL parameters between CAPD and HD patients. T -CL and CL/N of dialysis patients were equal to controls but those of CRF patients were significantly decreased. V-CL of dialysis patients, as well as CRF patients, was smaller than that of controls but the difference was not significant. Among nutritional status, degree of anemia, dialytic efficacy and duration of dialysis in CAPD patients, only serum albumin concentration (Alb) correlated well to all CL parameters. Hypoalbuminemic patients(Alb <3.6 gldL, n=20) had significantly decreased T -CL and CL/N compared to normoalbuminemic patients(Alb ?: 3.6 g/dL, n=15), and decreased CL/N and V-CL compared to controls. No differences in CL parameters were observed between the patients with a history of peritonitis (n=15) and without a history of peritonitis (n=20).

Conclusions

Oxidative metabolism of PMNL in CAPD patients was maintained with respect to superoxide productive volume, while the oxidative velocity was relatively impaired. Furthermore, it seems that albumin has a great influence on the oxidative metabolism of PMNL in CAPD patients.

Nutritional Markers during Peritoneal Dialysis: Data from the 1998 Peritoneal Dialysis Core Indicators Study

Objective

This analysis explores the nutritional status of adult U.S. peritoneal dialysis (PD) patients.

Design

The Peritoneal Dialysis Core Indicators Study is a prospective cross-sectional prevalence survey describing the care provided to a random sample of adult U.S. PD patients.

Methods and Population

Prevalence data were collected from a national random sample of 1381 adult PD patients participating in the United States End Stage Renal Disease (ESRD) program.

Results

The median age of these patients was 55 years, 61% were Caucasian; the leading cause of ESRD was diabetes mellitus. Age, sex, size, peritoneal permeability, dialysis adequacy, and nutritional indices did not differ between patients on continuous ambulatory PD and patients on automated PD. The dialysis prescriptions employed achieved mean weekly Kt/V urea (wKt/V) and creatinine clearance (wCCr) values of 2.22 ± 0.57 and 67.8 ± 22.5 L/1.73 m2/week, respectively. The PD patients were large, with a mean body weight of 77 ± 21 kg and body mass index (BMI) of 27 ± 8.6 kg/m2. The mean serum albumin of these patients was 3.5 ± 0.51 g/dL, and 43% of values fell below the National Kidney Foundation Dialysis Outcomes Quality Initiative's desired range. The PD patients had a normalized protein equivalent of nitrogen appearance (nPNA) of 1.0 ± 0.57 g/kg/day, a normalized creatinine appearance rate (nCAR) of 17 ± 7.3 mg/kg/day, and an estimated lean body mass (%LBM) of 62% ± 18% of body weight. Serum albumin correlated positively with patient size, nCAR, and nPNA, but negatively with age, the presence of diabetes mellitus, female gender, erythropoietin dose, the creatinine dialysate-to-plasma ratio results of peritoneal equilibration testing, and the dialysis portion of the wCCr. The duration of ESRD experience correlated negatively with both serum albumin and patient size, although these relationships were complex.

Conclusion

Peritoneal dialysis patients generally have marginal serum albumin levels, a finding incongruent with alternative measures of nutritional status, such as weight, BMI, and creatinine generation. Serum albumin is reduced in patients with high peritoneal permeability ( i.e., rapid transporters) and, because these patients generally have higher than average wCCr values, serum albumin is inversely correlated with the dialysis component of the wCCr. The presumptive nutritional indicators (BMI, %LBM, nPNA, and serum albumin) provide disparate estimates, varying from 10% to 50% for the prevalence of nutritionally stressed PD patients.

Answers to All Your Questions about Peritoneal Urea Clearance and Nutrit Ion in Capd Patients

In summary, SA and a number of other indices related to nutritional status have been identified as being strongly predictive of outcome in CAPD patients. Evidence connecting these indices to KTN urea, or even to protein intake, remains limited, however. Increased dialytic dose may well increase protein intake, but neither of these parameters have been shown prospectively to raise SA, total body nitrogen, or SGA status on a consistent basis. Studies addressing this issue, however, have been few and small, and more data are required. For now, we will likely continue to deal with malnutrition by attempting to raise small solute clearance and protein intake, but we should be aware that such measures will frequently be unsuccessful, and we must pay attention to other factors, particularly comorbidity.

It is clear from this review that there are many unanswered questions relating to this topic and that, in particular, the effect of prospective increases in the dialytic dose needs to be further elucidated.

The Removal Index for Evaluation of Dialysis

Objectives

To find an index of adequacy that takes into consideration the effect of the decreasing concentration of urea nitrogen in hemodialysis (HD) and can be used before treatments to quantitate the prescriptions with the same criterion for both HD and continuous ambulatory peritoneal dialysis (CAPD).

Design

The removal index was obtained through mathematical theories and then compared with the urea index (KT/V) values of the sample patients.

Patients

Thirty-two HD and 21 CAPD patients were included. All patients were dialyzed with optimal urea index values and had been stable for at least one year.

Results

The removal index in HD (ξHD) for each dialysis was 0.62±0.07, and the normalized removal index in CAPD (ξCAPD) was 0.59±0.11. There was no statistical significance. This result is consistent with the fact that no difference of morbidity or mortality exists between these two modalities.

Conclusion

After mathematical manipulation, the removal index in HD can be presented in the form of the urea reduction ratio, which is a retrospective measure to estimate the performance of hemodialysis. This study implies that the removal index is able to facilitate the prescriptions for adequate dialysis. The removal index can also be used to explain the reason why the urea index values are always larger in HD than in CAPD.

Helicobacter Pylori Infection: A New Cause of Anorexia in Peritoneal Dialysis Patients

♦ Objective

Helicobacter pylori (HP) infection has frequently been found in dialysis patients. Chronic infections induce overproduction of pro-inflammatory substances. Inflammation has been associated with cachexia and anorexia. We explored the relationship between HP infection, anorexia, and malnutrition in peritoneal dialysis (PD) patients.

♦ Patients and Methods

The study included 48 clinically stable PD patients divided into four groups: HP+ with anorexia (group I, n = 12); HP+ without anorexia (group II, n = 4); HP- with anorexia (group III, n = 5); and HP- without anorexia (group IV, n = 27). Infection with HP was diagnosed by breath test. Anorexia was evaluated using a personal interview and an eating motivation scale (VAS). The VAS included five questions that are answered before and after eating. The questions concern desire to eat, hunger, feeling of fullness, prospective consumption, and palatability. Biochemical markers of nutrition and inflammation were also determined.

♦ Results

At baseline, group I showed lower scores for desire to eat, hunger sensation, prospective consumption, and palatability. They also showed lower lymphocyte counts, prealbumin, transferrin, serum albumin, normalized equivalent of protein–nitrogen appearance (nPNA), and residual renal function (RRF). In addition, the same group showed higher levels of C-reactive protein (CRP) and more sensation of fullness than the remaining groups. In the entire series, we found significant linear correlations between the following markers of nutrition and certain questions on the VAS: albumin with before-lunch desire to eat ( r = 0.38, p < 0.05), and prealbumin with before-lunch hunger ( r = 0.41, p < 0.05) and after-lunch hunger ( r = -0.35, p < 0.05). Negative linear correlations were found between albumin and fullness before lunch ( r = -0.45, p < 0.01), and between prealbumin and before-lunch desire to eat ( r = -0.39, p < 0.05). Negative linear correlations were also seen between CRP and albumin ( r = -0.35, p < 0.05) and between CRP and prealbumin ( r = -0.36, p < 0.05). Similarly, CRP showed a negative correlation with before-lunch desire to eat ( r = -0.38, p < 0.05) and after-lunch desire to eat ( r = -0.45, p < 0.01). After HP eradication, group I showed a significant increase in markers of nutrition and in VAS scores for almost all questions. Simultaneously, they showed a decrease in CRP level. Significant differences were also found in lymphocyte count (1105 ± 259.4 cells/mm3 vs 1330.8 ± 316 cells/mm3, p < 0.05), nPNA (0.9 ± 0.16 g/kg/day vs 1.07 ± 0.3 g/kg/day, p < 0.05), prealbumin (26.7 ± 6.5 mg/dL vs 33.9 ± 56.6 mg/dL, p < 0.01), albumin (3.48 ± 0.3 g/dL vs 3.67 ± 0.35 g/dL, p < 0.05), CRP (1.16 ± 1.14 mg/dL vs 0.88 ± 1.2 mg/dL, p < 0.054), before-lunch desire to eat (56.6 ± 6.8 vs 72.2 ± 4, p < 0.001), after-lunch desire to eat (5.4 ± 2.6 vs 12.3 ± 2, p < 0.01), hunger before lunch (55.4 ± 5.4 vs 73.1 ± 4.6, p < 0.001), hunger after lunch (5.8 ± 2.9 vs 11 ± 4, p < 0.01), fullness before lunch (36.6 ± 10.3 vs 18.7 ± 8.8, p < 0.001), consumption after lunch (5 ± 4.7 vs 17.5 ± 18, p < 0.05), and palatability (61 ± 5.3 vs 74.1 ± 4.1, p < 0.001).

♦ Conclusion

Infection with HP is associated with anorexia, inflammation, and malnutrition in PD patients. Eradication of HP significantly improves this syndrome. Residual renal function seem to have a protective effect on appetite preservation. The present study supports the hypothesis of the involvement of inflammation in the pathogenesis of malnutrition in PD patients.

Growth Hormone and Malnutrition in Dialysis Patients

Objective

To review the normal function of the growth hormone (GH) insulin-like growth factor (IGF) axis, how it is altered in end-stage renal failure, how this may contribute to malnutrition in dialysis patients, and how therapy with recombinant human growth hormone (rHuGH) and recombinant human IGF-I (rHuIGF-1)might be used to treat malnutrition in these patients.

Data Sources

Studies in the literature dealing with the GH-IGF endocrine axis and its role in uremic malnutrition.

Study Selection

Eight studies in which uremic adults were treated with either rHuGH or rHuIGF-I.

Data Extraction

Data were abstracted from all of these studies.

Results

The review shows that there are marked abnormalities of the GH-IGF axis in uremic patients and that these lead to a state of GH resistance, which can be overcome by pharmacological doses of rHuGH. A small number of clinical studies in uremic adults suggests that both rHuGH and rHuIGF-I have dramatic beneficial effects on nutritional status in these patients.

Conclusions

rHuGH and rHuIGF-I have both been shown to have a beneficial effect on nutritional status in shortterm studies on small numbers of patients. Further studies need to be done for longer periods in larger groups of patients. Areas for additional research are suggested.