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

Elevated serum interleukin-18 level is associated with all-cause mortality in stable hemodialysis patients independently of cardiac dysfunction

Background

High circulating interleukin (IL)-18 level predicts a higher hospitalization rate among dialysis patients, possibly through cardiovascular mechanisms; however, whether higher IL-18 level is associated with mortality in dialysis patients is less clear. In addition, its impacts on left ventricular (LV) function are also unknown. We conducted a cohort study to examine the impacts of IL-18 level on LV function and prognosis among clinically stable hemodialysis patients.

Methods

Clinically stable patients undergoing maintenance hemodialysis (≥3 months) were prospectively enrolled from December 2008 to January 2009, and were followed up for 31 months. The enrolled patients (41% male, 66.4±10.9 years of age) received 2-dimensional echocardiography and myocardial deformation (strain) analysis, including LV peak systolic longitudinal strain (GLS) and circumferential strain (CS). Laboratory measurements were also performed. Cox regression analysis was used to investigate prognostic factors.

Results

Seventy-five patients were stratified into 2 groups by the median value of IL-18 (654.2 pg/ml). Between these 2 groups, there was no significant difference in baseline characteristics including LV ejection fraction. The high IL-18 group had a worse LV systolic function as demonstrated by reduced GLS and CS. Seventeen patients (22.7%) died during the follow-up period. Multivariate Cox regression analysis showed that low serum albumin, the presence of hypertension, high serum IL-18, and less negative GLS (>−15%) were independently associated with all-cause mortality. No significant interaction between IL-18 and less negative GLS was noted in the final Cox model.

Conclusion

Hemodialysis patients with high IL-18 levels tend to have worse LV systolic function and higher mortality rate. However, elevated serum IL-18 level is predictive of poor prognosis among stable hemodialysis patients, independently of LV dysfunction. This suggests an additional value of IL-18 to echocardiographic study in predicting all-cause mortality, and IL-18 may be helpful in early risk stratification of hemodialysis patients.

Body composition monitor assessing malnutrition in the hemodialysis population independently predicts mortality

OBJECTIVE

Malnutrition is a known predictor of mortality in the general and hemodialysis populations. However, diagnosing malnutrition in dialysis patients remains problematic. Body composition monitoring (BCM) is currently used mainly for assessing overhydratation in hemodialysis patients, but it also offers the possibility of evaluating nutrition status. This study explored whether malnutrition diagnosed by BCM predicts mortality at up to 54 months follow-up in prevalent hemodialysis patients.

DESIGN

This was a retrospective epidemiology cohort study. Dialysis patients with baseline BCM measurement between 2008 and 2013 were enrolled. The observation period was up to 54 months follow-up.

SUBJECTS

A total sample consisted of 960 chronic hemodialysis participants.

INTERVENTION

All data were retrieved from medical records. Nutrition status was estimated by BCM; malnutrition was diagnosed as lean tissue index less than 10% of the normal value.

MAIN OUTCOME MEASURE

Cox regression was performed to identify whether low LTI predicted mortality in hemodialysis patients.

RESULTS

BCM-diagnosed malnutrition (hazard ratio [HR] 1.66; 95% confidence interval [CI] 1.1; 2.44), higher age (HR 1.05; 95% CI 1.03; 1.07), longer dialysis vintage (HR 1.00; 95% CI 1.00; 1.00), central venous catheter use (HR 1.96; 95% CI 1.28; 2.99), and low serum albumin (HR 0.91; 95% CI 0.87; 0.95) contributed significantly to the Cox regression model on mortality.

CONCLUSION

BCM-diagnosed malnutrition in chronic hemodialysis patients is an independent predictor of mortality at up to 54 months follow-up and is associated with a 1.66-fold higher risk of dying compared with normal nutrition status. Whether intervention (e.g., nutritional supplementation) might improve nutrition and reduce the higher risk of mortality in malnutrition patients on hemodialysis remains a challenge for future research.

Effect of hemoglobin variability on mortality and some cardiovascular parameters in hemodialysis patients

BACKGROUND AND OBJECTIVES

Most hemodialysis patients show hemoglobin fluctuations between low-normal and high levels. This hemoglobin variability may cause left ventricle hypertrophy and may increase mortality as well. Recently, many studies were designed to evaluate the effect of hemoglobin variability on mortality but results were conflicting. We aimed to investigate the effect of hemoglobin variability on mortality and some cardiovascular parameters in hemodialysis population.

DESIGN, SETTING, PARTICIPANTS AND MEASUREMENTS

Hundred and seventy-five prevalent hemodialysis patients classified into three hemoglobin variability groups according to their hemoglobin levels throughout 24 month observation period: Low-Normal, Low-High, Normal-High. Groups were compared in terms of laboratory, demographical data and mortality rates, initial and the end of 24 month echocardiographic data. Initial and last echocardiographic data were compared within groups in terms of left ventricle mass index increase.

RESULTS

Mortality rates and cardiovascular risk factors such as coronary heart disease, diabetes mellitus and hypertension that may affect mortality were same between three groups. There was no significant difference between three groups in terms of echocardiographic and laboratory parameters. Only Low-High group showed significant increase on left ventricle mass index when initial and last echocardiographic parameters were compared.

CONCLUSIONS

Consistent with previous studies, we found that most of the patients exhibited hemoglobin variability and our study is consistent with some of the studies that did not find any relationship between hemoglobin variability and mortality. Firstly, in this study based on objective data, it was shown that hemoglobin variability has adverse effect on left ventricle geometry independent from anemia.

The Saga of Two Centuries of Urea: Nontoxic Toxin or Vice Versa?

In the early 1700s, a substance ultimately identified as urea was reported for the first time in urine. About a century later, in 1828, synthesis of this organic compound was achieved, thus giving rise to modern organic chemistry. In parallel, physicians showed that urine comes from the kidneys and contains large amounts of urea, which is produced outside of the kidneys, establishing the humoral approach of renal physiology. Urea was the first uremic retention solute to be identified and it has been used as a marker of renal disease ever since. However, progress in the knowledge of urea metabolism has shown that it is susceptible to many extrarenal variations and, therefore, it cannot be a reliable marker of renal function. It reflects protein intake in the stable patient and has been used to assess nutrition and dialysis efficacy in renal patients. Although it has been studied for almost 200 years, its toxicity has been largely debated. An indirect toxicity occurring through carbamylation of lysine residues is now well established and some evidence from recent work also supports direct toxicity of urea, offering additional rationale for interventional prevention of uremic complications.

A plasma long-chain acylcarnitine predicts cardiovascular mortality in incident dialysis patients

Background

The marked excess in cardiovascular mortality that results from uremia remains poorly understood.

Methods and Results

In 2 independent, nested case‐control studies, we applied liquid chromatography‐mass spectrometry‐based metabolite profiling to plasma obtained from participants of a large cohort of incident hemodialysis patients. First, 100 individuals who died of a cardiovascular cause within 1 year of initiating hemodialysis (cases) were randomly selected along with 100 individuals who survived for at least 1 year (controls), matched for age, sex, and race. Four highly intercorrelated long‐chain acylcarnitines achieved the significance threshold adjusted for multiple testing (P<0.0003). Oleoylcarnitine, the long‐chain acylcarnitine with the strongest association with cardiovascular mortality in unadjusted analysis, remained associated with 1‐year cardiovascular death after multivariable adjustment (odds ratio per SD 2.3 [95% confidence interval, 1.4 to 3.8]; P=0.001). The association between oleoylcarnitine and 1‐year cardiovascular death was then replicated in an independent sample (n=300, odds ratio per SD 1.4 [95% confidence interval, 1.1 to 1.9]; P=0.008). Addition of oleoylcarnitine to clinical variables improved cardiovascular risk prediction using net reclassification (NRI, 0.38 [95% confidence interval, 0.20 to 0.56]; P<0.0001). In physiologic profiling studies, we demonstrate that the fold change in plasma acylcarnitine levels from the aorta to renal vein and from pre‐ to post hemodialysis samples exclude renal or dialytic clearance of long‐chain acylcarnitines as confounders in our analysis.

Conclusions

Our data highlight clinically meaningful alterations in acylcarnitine homeostasis at the time of dialysis initiation, which may represent an early marker, effector, or both of uremic cardiovascular risk.

Predominant gray matter volume loss in patients with end-stage renal disease: a voxel-based morphometry study

To investigate the pattern of brain volume changes in patients with end-stage renal disease (ESRD) using voxel-based morphometry (VBM) and correlation with clinical and neuropsychological (NP) tests. Fifty seven ESRD patients with no anatomical abnormalities in conventional magnetic resonance imaging [24 patients with abnormal NP scores, 16 male, 39 ± 12 years; 33 patients with normal NP scores, 23 male, 35 ± 9.7 years] and 22 age- and gender-matched healthy controls (14 male, 36 ± 10.1 years) were recruited in this study. Results from VBM analysis were analyzed with ANOVA test among 3 groups (controls, minimal nephro-encephalopathy group, non-nephro-encephalopathy group). Multiple linear regression analysis was used to investigate the effect of serum urea and creatinine, and dialysis duration on the brain volumes in ESRD patients. Correlation analysis was performed to investigate the association between NP scores with the brain volumes in ESRD patients. Compared with healthy controls, ESRD patients showed diffusely decreased gray matter volume that further decreased in the presence of encephalopathy. Multiple linear regression results showed that serum urea was negatively associated with changes in gray matter volume in many regions, while dialysis duration was negatively associated with some white matter volume changes (All P < 0.05, AlphaSim correction). NP scores correlated with some decreased gray matter volume in ESRD patients (All P < 0.05, AlphaSim correction). No correlation was found between white matter volume and any NP test scores in ESRD patients. This study found predominantly decreased gray matter volume in ESRD patients, which was associated with neurocognitive dysfunction. Serum urea level may be a risk factor for decreased gray matter in ESRD patients.

Risk factors for mortality in hemodialysis patients: two-year follow-up study

BACKGROUND

End-stage renal disease (ESRD) patients under hemodialysis (HD) have high mortality rate. Inflammation, dyslipidemia, disturbances in erythropoiesis, iron metabolism, endothelial function, and nutritional status have been reported in these patients. Our aim was to identify any significant association of death with these disturbances, by performing a two-year follow-up study.

METHODS AND RESULTS

A large set of data was obtained from 189 HD patients (55.0% male; 66.4 ± 13.9 years old), including hematological data, lipid profile, iron metabolism, nutritional, inflammatory, and endothelial (dys)function markers, and dialysis adequacy.

RESULTS

35 patients (18.5%) died along the follow-up period. Our data showed that the type of vascular access, C-reactive protein (CRP), and triglycerides (TG) are significant predictors of death. The risk of death was higher in patients using central venous catheter (CVC) (Hazard ratio [HR] = 3.03, 95% CI = 1.49-6.13), with higher CRP levels (fourth quartile), compared with those with lower levels (first quartile) (HR = 17.3, 95% CI = 2.40-124.9). Patients with higher TG levels (fourth quartile) presented a lower risk of death, compared with those with the lower TG levels (first quartile) (HR = 0.18, 95% CI = 0.05-0.58).

CONCLUSIONS

The use of CVC, high CRP, and low TG values seem to be independent risk factors for mortality in HD patients.

The impact of pretransplant hypoalbuminemia on survival in patients with leukemia who underwent allogeneic hematopoietic stem cell transplantation (alloHSCT): a nutritional problem?

OBJECTIVE

Serum albumin level is considered to be a marker reflecting the nutritional status in both healthy subjects and patients with malignancies. In this study we sought to investigate the association between pretransplantation serum albumin levels and prognosis among patients with leukemia who underwent allogeneic hematopoietic stem cell transplantation (alloHSCT).

METHODS

We retrospectively analyzed the data of 102 patients who underwent alloHSCT from 2004 to 2010. Pretransplant serum albumin, D-dimer, creatinine, and fibrinogen levels drawn within 10 days before transplantation were obtained from patient files. All parameters were divided into 2 groups: normal levels (group 1) versus abnormal levels (group 2). Our normal range of serum albumin is 3.2-5.2 g/dL; patients with pretransplantation albumin level ≥3.2 g/dL were included in group 1 versus group 2 with <3.2 g/dL.

RESULTS

The patients included 42 (41.1%) female and 60 (58.9%) male patients. The diagnoses were acute myeloblastic leukemia in 65 (63.7%) and acute lymphoblastic leukemia in 37 (36.3%). The median age was 26.0 years (range, 13-57). Univariate and multivariate analysis showed that patients with serum albumin levels <3.2 g/dL experienced significantly lower overall survival (OS) compared with ≥3.2 g/dL (hazard ratio [HR] 2.32 [range, 1.23-4.54] and HR 2.70 [range 1.38-5.26], respectively; P = .009). The median (range) OS in group 2 was 230.0 (184.0-544.0) days versus 570.5 (249.5-1,101.0) days in group 1 (P = .007). For disease free survival (DFS) evaluation, univariate and multivariate analysis showed that patients with serum albumin levels <3.2 g/dL had significantly lower values compared with patients with serum albumin ≥3.2 g/dL. (HR 2.17 [range 0.98-4.76] and HR 2.85 [range, 1.25-6.66], respectively; P = .046). The median (range) DFS in group 2 was 184.0 (61.0-524.0) days versus 445.0 (199.0-917.5) days in group 1 (P = .045). Among the patient characteristics the presence of infection was a significant independent variable for worse OS (HR 2.12 [range, 0.98-4.36], P = .036). The other parameters-age, sex, donor status, time to transplant interval, conditioning regimens, HLA status, and number of total infused CD34(+) cells-showed no significant effect on OS and DFS (P = .05).

CONCLUSIONS

Pretransplantation decreased serum albumin levels were associated with poor survival in patients with leukemia who underwent alloHSCT.

Evidence-based cardiology in hemodialysis patients

Cardiac events are the major cause of death in hemodialysis patients. Because of the paucity of randomized clinical trials (RCTs) in hemodialysis patients, most cardiovascular therapies in this population are based on observational studies or results extrapolated from studies that excluded hemodialysis patients. However, associations discovered in observational studies do not prove causality, and these studies often report surrogate outcomes rather than clinical end points. Furthermore, interventions that show effectiveness in the general population may have drastically different outcomes and side effect profiles in hemodialysis patients. This review discusses the results of RCTs undertaken recently to evaluate cardiovascular therapies in hemodialysis patients and emphasizes clinically relevant outcomes. Although some interventions have produced similar outcomes in hemodialysis patients and the general population, others have not, suggesting that the management of cardiovascular disease in hemodialysis patients may require strategies that differ from the best practice guidelines applied to general population.

Laboratory performance in albumin and total protein measurement using a commutable specimen: results of a College of American Pathologists study

CONTEXT

Discrepant results for serum constituents were observed among peer groups in the College of American Pathologists Comprehensive Chemistry Survey.

OBJECTIVES

To assess the performance of serum albumin and total protein measurement procedures and to evaluate the commutability of the conventional survey specimens.

DESIGN

A fresh frozen, off-the-clot serum sample was included along with 4 conventional survey specimens. The fresh frozen, off-the-clot serum sample was prepared in a manner expected to confer commutability with native clinical samples.

RESULTS

For the fresh frozen, off-the-clot serum sample, the mean values for 17 peer-groups were -0.07 to 0.32 g/dL from the bromocresol green albumin designated comparison method, whereas 4 VITROS (Ortho Clinical Diagnostics, Rochester, New York) peer groups differed by -0.29 to -0.37 g/dL (15 of 21 differences [71%] had P < .001). For bromocresol purple albumin methods, the mean differences from the designated comparison method from 8 peer groups were 0.25 to 0.47 g/dL (all had P < .001). For total protein methods, 23 peer group mean values were -0.07 to 0.15 g/dL from the reference measurement procedure (12 of 24 [50%] had P < .001). The Beckman (Fullerton, California) Synchron LX20 had a bias of -0.30 g/dL (P <.001). The commutability of the conventional specimens was acceptable for 23 of 24 bromocresol green method-material combinations (96%) and 13 of 16 bromocresol purple albumin method-material combinations (81%). All (100%) of the 36 method-material combinations had acceptable commutability for total protein.

CONCLUSIONS

One (2.2%) of the instrument systems (Synchron) using bromocresol green and none (0%) of the instrument systems using bromocresol purple had satisfactory total-error performance for albumin measurement. Differences in results between bromocresol green and bromocresol purple methods precluded using common reference intervals for interpreting results for serum albumin. Eight of 9 instrument systems (86.5%) had satisfactory total-error performance for total protein measurement.

Validation of Mini Nutritional Assessment Scale in peritoneal dialysis patients

INTRODUCTION

Malnutrition is a negative predictive factor for survival in end stage renal disease (ESRD) patients. Coincidence of malnutrition, inflammation and atherosclerosis (MIA syndrome) in the dialysis population is an exceptionally poor outcome event. Due to flexibility, ease of performance and reproducibility, clinical scales are of particular value in assessment of nutritional status in ESRD patients. The aim of the present study was to evaluate the clinical value of Mini Nutritional Assessment (MNA) in peritoneal dialysis (PD) patients.

MATERIAL AND METHODS

Nutritional status was assessed in 41 peritoneal dialysis patients by means of the MNA scale and malnutrition inflammation score (MIS). Some other clinical and laboratory parameters associated with nutritional status were analyzed. Patients were followed up for 30 months.

RESULTS

In the analyzed group of patients a good nutritional state was diagnosed in 22 patients (54%), risk of malnutrition in 17 (41%) and malnutrition in 2 patients (5%) based on the MNA scale. A strong correlation between MNA based nutritional status and MIS was found (r = -0.85, p < 0.01, ANOVA, p < 0.01). Differences in time on dialysis, body mass index, concentration of albumin, cholesterol and triglycerides were noted between at risk/malnourished and well-nourished (according to MNA) patients. Statistically significant factors determining survival of patients by Cox proportional hazard analysis were age (HR 1.07), being at risk/malnourished according to MNA (HR 5.7), MIS (HR 1.2), and albumin (HR 0.13).

CONCLUSIONS

The MNA scale is a valuable, clinically suitable tool for assessment of nutritional status in peritoneal dialysis patients. Risk of malnutrition and malnutrition diagnosed by MNA identifies patients at high mortality risk.

Carbamylation of serum albumin and erythropoietin resistance in end stage kidney disease

BACKGROUND AND OBJECTIVES

The mechanisms underlying erythropoietin resistance are not fully understood. Carbamylation is a post-translational protein modification that can alter the function of proteins, such as erythropoietin. The hypothesis of this study is that carbamylation burden is independently associated with erythropoietin resistance.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In a nonconcurrent prospective cohort study of incident hemodialysis patients in the United States, carbamylated albumin, a surrogate of overall carbamylation burden, in 158 individuals at day 90 of dialysis initiation and erythropoietin resistance index (defined as average weekly erythropoietin dose [U] per kg body weight per hemoglobin [g/dl]) over the subsequent 90 days were measured. Linear regression was used to describe the relationship between carbamylated albumin and erythropoietin resistance index. Logistic regression characterized the relationship between erythropoietin resistance index, 1-year mortality, and carbamylation.

RESULTS

The median percent carbamylated albumin was 0.77% (interquartile range=0.58%-0.93%). Median erythropoietin resistance index was 18.7 units/kg per gram per deciliter (interquartile range=8.1-35.6 units/kg per gram per deciliter). Multivariable adjusted analysis showed that the highest quartile of carbamylated albumin was associated with a 72% higher erythropoietin resistance index compared with the lowest carbamylation quartile (P=0.01). Increasing erythropoietin resistance index was associated with a higher risk of death (odds ratio per unit increase in log-erythropoietin resistance index, 1.69; 95% confidence interval, 1.06 to 2.70). However, the association between erythropoietin resistance index and mortality was no longer statistically significant when carbamylation was included in the analysis (odds ratio, 1.44; 95% confidence interval, 0.87 to 2.37), with carbamylation showing the dominant association with death (odds ratio for high versus low carbamylation quartile, 4.53; 95% confidence interval, 1.20 to 17.10).

CONCLUSION

Carbamylation was associated with higher erythropoietin resistance index in incident dialysis patients and a better predictor of mortality than erythropoietin resistance index.

Modeling hybrid rough set-based classification procedures to identify hemodialysis adequacy for end-stage renal disease patients

Healthcare problems observed in the majority of end-stage renal disease (ESRD) patients regarding hemodialysis (HD) treatment are serious issues for the Taiwanese healthcare services, and an interesting topic is thus the adequacy of HD therapy. This study successfully models a hybrid procedure to measure HD adequacy to assess therapeutic effects and to explore the relationship between accuracy and coverage for interested parties. The proposed model has better accuracy, a lower standard deviation, and fewer attributes than the listed methods under various evaluation criteria. The study results are useful to subsequent researchers to develop suitable applications, and to ESRD patients and their doctors to ensure satisfactory medical quality.

Changes in anthropometry and mortality in maintenance hemodialysis patients in the HEMO Study

BACKGROUND

Poor nutritional status has been associated with worse patient survival in maintenance hemodialysis patients. Anthropometric values are important nutritional measures, incorporating muscle and fat mass. However, the association of changes in anthropometry, including midarm circumference (MAC) and skinfold measurements, with mortality in hemodialysis patients remains unknown. Accordingly, we explored this association in the Hemodialysis (HEMO) Study.

STUDY DESIGN

Post hoc analysis of cohort data from a clinical trial.

SETTING & PARTICIPANTS

1,846 hemodialysis patients enrolled in the HEMO Study.

PREDICTORS

MAC and skinfold measurements.

OUTCOMES

Longitudinal changes in MAC and skinfolds were jointly modeled using repeated measures and survival modeling. Time-to-event outcomes were all-cause mortality, cardiac death and hospitalization, and infection-related death.

RESULTS

Mean MAC was 30.1 cm, and mean baseline sum of subscapular, biceps, and triceps skinfolds was 42.4 mm. During a median follow-up of 2.5 years, there were 845 deaths. During follow-up, MAC and the skinfold measurement declined 0.26 cm and 1.1 mm per year, respectively. Declines in MAC (per cm) and skinfold (per mm) measurements were associated with higher all-cause mortality (HRs of 1.58 [95% CI, 1.29-1.94; P < 0.001] and 1.06 [95% CI, 0.99-1.13; P = 0.09], respectively), poorer cardiac outcomes (HRs of 1.49 [95% CI, 1.23-1.81; P < 0.001] and 1.05 [95% CI, 0.99-1.10; P = 0.09], respectively), and higher infection-related hospitalization (HRs of 2.45 [95% CI, 1.55-3.88; P < 0.001] and 1.16 [95% CI, 0.98-1.37; P = 0.08], respectively). The association between declining MAC and skinfold with patient survival was most notable for those with body mass index (BMI) ≤25 kg/m2 (HRs of 2.41 [95% CI, 1.81-3.19; P < 0.001] and 1.22 [95% CI, 1.10-1.35; P < 0.001], respectively).

LIMITATIONS

Prevalent dialysis patients only, excluding individuals weighing >85 kg.

CONCLUSIONS

Declines in skinfold thickness were not associated significantly with outcomes except for participants with BMI ≤25 kg/m2. Declines in MAC are associated significantly with all-cause mortality and cardiac outcomes in hemodialysis patients, most notably in those with BMI ≤25 kg/m2.

Determination of the relationship between adequacy of dialysis and quality of life and self-care agency

AIM AND OBJECTIVES

To investigate the relationship between the dialysis adequacy and the quality of life and self-care agency.

BACKGROUND

Haemodialysis (HD), which is the leading treatment option for chronic renal failure (CRF), leads to significant changes in the life of the patient. These changes affecting almost all the dimensions of life also negatively affect the quality of life and self-care agency.

DESIGN

Descriptive study.

METHODS

The research was conducted with a total of 112 patients who had been admitted to two private dialysis centres between May 2009 and September 2010, who met the research criteria. The Data Collection Form for the Socio-demographic and Medical Characteristics, the Biochemical and Medical Parameters Form to determine the adequacy of dialysis, the SF-36 Quality of Life Scale and the Self-Care Agency Scale were used in the research.

RESULTS

A significant relationship was found between Kt/V, one of the parameters used for the assessment of dialysis adequacy, and the emotional role scores of the SF-36 Quality of Life Scale and between the URR level and physical functioning (r = +0.192, p = 0.045) and emotional role scores (r = +0.284, p = 0.003). No significant relationship could be found between the self-care agency and the evaluated parameters.

CONCLUSIONS

Kt/V and URR, which have an effect on dialysis adequacy, may affect the quality of life. Our results are similar to those of previous studies, which showed that Kt/V and URR affect the quality of life.

RELEVANCE TO CLINICAL PRACTICE

It was recommended to regularly control the parameters used for the assessment of dialysis adequacy and to evaluate their effects on the quality of life, to determine the most affected quality of life subparameters and to address these problems and solve them.

Challenges and management of high-flow arteriovenous fistulae

The Kidney Dialysis Outcomes Quality Initiative and Fistula First Initiative have embraced the arteriovenous fistula as the gold standard for hemodialysis accesses. Despite this status, fistulae are fraught with complex issues ranging from a high primary failure rate to high flow resulting in increased cardiovascular morbidity. It is important not to overlook the insidious peril of a hyperfunctioning access that may actively promote cardiac overload, cardiopulmonary recirculation, rapid access growth with aneurysm enlargement, recurrent venous stenosis resulting in access failure, and inflow/outflow mismatch. Once recognized, flow can and should be reduced to mitigate these and other negative effects.

Monitoring of hemodialysis quality-of-care indicators: why is it important?

BACKGROUND

Meeting specific guideline targets is associated with improved survival rates and reduced hospitalizations in the dialysis population. This prospective work evaluated the adequacy of hemodialysis quality indicators in an in-center hemodialysis population with severe comorbidities, and assessed whether clinical practice could impact intermediate outcomes.

METHODS

All the chronic hemodialysis patients treated in Rouen University Hospital hemodialysis Unit between January 2009 and April 2010 were included in this observational study. Every quarter, mean levels and prevalence of conformity were collected for the following indicators: anemia, dialysis dose, serum calcium and phosphorus, PTH, 25OH-vitamin D, albumin, serum bicarbonate, LDL-cholesterol, serum β2-microglobulin, systolic and diastolic blood pressure, intradialytic hypotension and vascular access. Conformity of quality-of-care indicators was determined according to targets defined by international guidelines, whenever available.

RESULTS

Altogether, 124 patients were included in the study. Thirty-three patients were evaluated during the entire follow-up period. An improvement in the percentage of conformity was observed for hemoglobin, dialysis dose, phosphates, PTH, serum bicarbonate and β2-microglobulin in the global population. Failure to improve conformity rates for several indicators, including serum albumin, was found, possibly depending on patients' comorbidities rather than on quality of care.

CONCLUSION

Overall, this study shows that following quality-of-care indicators can improve clinical practice by identifying center-specific weaknesses, prompting the establishment of corrective measures. Finally, we suggest that the definition and targets of some indicators, especially hypertension and LDL-cholesterol, be reviewed, since evidence of their association with mortality is not demonstrated.

Insulin resistance and protein metabolism in chronic hemodialysis patients

OBJECTIVE

Loss of lean body mass (sarcopenia) is associated with increased morbidity and mortality in patients receiving chronic hemodialysis (CHD). Insulin resistance (IR), which is highly prevalent in patients receiving CHD, has been proposed to play a critical role in the development of sarcopenia. The aim of this study was to examine the effect of IR on amino acid metabolism in patients receiving CHD.

DESIGN

This was a cross-sectional study.

SUBJECTS

The study included 12 prevalent (i.e., patients that have been on dialysis for more than 90 days) African American patients receiving CHD.

METHODS

IR was measured as glucose disposal rate (GDR) determined from hyperinsulinemic euglycemic clamp (HGEC) studies performed 3 consecutive times. Plasma amino acid (AA) concentrations were measured by real-time high-performance liquid chromatography (HPLC) throughout the clamp study. The primary outcome was percentage change in leucine concentrations during the clamp study. The main predictor was the GDR measured simultaneously during the HGEC studies. Mixed model analysis was used to account for repeated measures.

RESULTS

All individual AA concentrations declined significantly in response to high-dose insulin administration (P < .001). There was a significant direct association between GDR by HECG studies and the percentage change in leucine concentration (P = .02). Although positive correlations were observed between GDR values and concentration changes from baseline for other AAs, these associations did not reach statistical significance.

CONCLUSIONS

Our results suggest that the severity of IR of carbohydrate metabolism is associated with a lesser decline in plasma leucine concentrations, suggesting a similar resistance to protein anabolism. Insulin resistance represents a potential mechanism for sarcopenia commonly observed in patients receiving CHD.

Quality-of-care indicators among remote-dwelling hemodialysis patients: a cohort study

BACKGROUND

We hypothesized that the higher mortality for hemodialysis patients who live farther from the closest attending nephrologist compared with patients living closer might be due to lower quality of care.

STUDY DESIGN

Population-based longitudinal study.

SETTING & PARTICIPANTS

All adult maintenance hemodialysis patients with measurements of quality-of-care indicators initiating hemodialysis therapy between January 2001 and June 2010 in Northern Alberta, Canada.

PREDICTORS

Hemodialysis patients were classified into categories based on the distance by road from their residence to the closest nephrologist: ≤50 (referent), 50.1-150, 150.1-300, and >300 km.

OUTCOMES

Quality-of-care indicators were based on published guidelines.

MEASUREMENTS

Quality-of-care indicators at 90 days following initiation of hemodialysis therapy and, in a secondary analysis, at 1 year.

RESULTS

Measurements were available for 1,784 patients. At baseline, the proportions of patients residing in each category were 69% for ≤50 km to closest nephrologist; 17%, 50.1-150 km; 7%, 150.1-300 km; and 7%, >300 km. Those who lived farther away from the closest nephrologist were less likely to have seen a nephrologist 90 days prior to the initiation of hemodialysis therapy (P for trend = 0.008) and were less likely to receive Kt/V of 1.2 (adjusted OR, 0.50; 95% CI, 0.30-0.84; P for trend = 0.01). Remote location also was associated with suboptimal levels of phosphate control (P for trend = 0.005). There were no differences in the prevalence of arteriovenous fistulas or grafts or hemoglobin levels across distance categories.

LIMITATIONS

Registry data with limited data for non-guideline-based quality indicators.

CONCLUSIONS

Although several quality-of-care indicators were less common in remote-dwelling hemodialysis patients, these differences do not appear sufficient to explain the previously noted disparities in clinical outcomes by residence location.

Energy metabolism, body composition, and urea generation rate in hemodialysis patients

Hemodialysis (HD) adequacy is currently assessed using normalized urea clearance (Kt/V), although scaling based on Watson volume (V) may disadvantage women and men with low body weight. Alternative scaling factors such as resting energy expenditure and high metabolic rate organ mass have been suggested. The relationship between such factors and uremic toxin generation has not been established. We aimed to study the relationship between body size, energy metabolism, and urea generation rate. A cross-sectional cohort of 166 HD patients was studied. Anthropometric measurements were carried on all. Resting energy expenditure was measured by indirect calorimetry, fat-free mass by bio-impedance and total energy expenditure by combining resting energy expenditure with a questionnaire-derived physical activity data. High metabolic rate organ mass was calculated using a published equation and urea generation rate using formal urea kinetic modeling. Metabolic factors including resting energy expenditure, total energy expenditure and fat-free mass correlated better with urea generation rate than did Watson volume. Total energy expenditure and fat-free mass (but not Watson Volume) were independent predictors of urea generation rate, the model explaining 42% of its variation. Small women (<mean V) had a significantly higher urea generation rate per kg than women with higher V. Similarly urea generation rate normalized to fat-free mass was significantly greater in small women than in all others (significant only in comparison to larger men). Exercise-related energy expenditure correlated significantly with urea generation rate. Energy metabolism, body composition and physical activity play important roles in small solute uremic toxin generation in HD patients and hence may impact on minimum dialysis requirements. Small women generate relatively more small solute toxins than other groups and thus may have a higher relative need for dialysis.

Renal replacement therapy in healthy adult horses

BACKGROUND

Renal replacement therapy (RRT) has been implemented extensively in people to facilitate recovery from acute renal failure (ARF). RRT has not been explored in horses, but might provide a further treatment option in horses with ARF.

OBJECTIVE

To investigate efficacy and safety of RRT in horses.

ANIMALS

Five healthy adult horses.

METHODS

A prospective study was performed on horses restrained in stocks and intravenously connected to a commercial RRT machine to allow continuous venovenous hemodiafiltration to be performed for 6 hours. The RRT machine was set at the following flow rates: blood flow rate 250 mL/min; dialysate rate 3,000 mL/h; prefilter replacement pump 3,000 mL/h; and postfilter replacement pump rate 2,000 mL/h. Balanced electrolyte solution was used as dialysate and replacement fluid. Heart rate, respiratory rate, body temperature, direct arterial blood pressure, urine output, and various clinicopathologic parameters were measured over the study period.

RESULTS

Renal replacement therapy was successfully performed in horses, resulting in a mean creatinine clearance of 0.127 mL/kg/min (68.9 mL/min) and urea reduction ratio of 24%. No adverse effects were detected although a significant decrease in rectal temperature was observed (P ≤ .007). A significant increase in serum phosphorus (P ≤ .001) and decrease in BUN (P < .001) were also noted. A significant prolongation of prothrombin (P < .01) and partial thromboplastin time (P < .0001) were observed along with a decrease in platelet count (P ≤ .04).

CONCLUSIONS AND CLINICAL IMPORTANCE

Renal replacement therapy can safely and effectively be used in adult horses.

A randomized controlled trial of intensive periodontal therapy on metabolic and inflammatory markers in patients With ESRD: results of an exploratory study

BACKGROUND

Periodontitis is a novel risk factor for inflammation and cardiovascular disease in the dialysis population. Limited information exists about the impact of periodontal therapy in patients receiving dialysis.

STUDY DESIGN

Randomized controlled trial to assess feasibility and gather preliminary data.

SETTING & PARTICIPANTS

Dialysis patients with moderate/severe chronic periodontitis.

INTERVENTION

Intensive treatment, consisting of scaling and root planing, extraction of hopeless teeth, and placement of local-delivery antibiotics, was performed at the baseline visit for treatment-group patients and after study completion for control-group patients.

OUTCOMES

Outcomes were feasibility (screening, recruitment, enrollment, adverse events, and study withdrawal/completion), clinical periodontal parameters (probing depth, clinical attachment level, bleeding on probing, gingival index, and plaque index), and serum albumin and interleukin 6 levels at 3 and 6 months postintervention.

RESULTS

342 dialysis patients were approached for participation: 53 were randomly assigned, with 26 participants assigned to immediate treatment and 27 assigned to a control arm for treatment after 6 months. 51 patients completed baseline appointments; 46 were available for 3-month follow-up, 45 were available for 6-month follow-up examinations, and 43 completed all visits. At 3 months, there was a statistically significant improvement for the treatment group compared to the control group for 3 periodontal parameters: mean probing depth (P = 0.008), extent of probing depth ≥4 mm (P = 0.02), and extent of gingival index ≥1 (P = 0.01). However, by 6 months, the difference between groups was no longer present for any variable except probing depth ≥4 mm (P = 0.04). There was no significant difference between groups for serum albumin or high-sensitivity interleukin 6 level at any time when adjusted for body mass index, diabetic status, and plaque index.

LIMITATIONS

Small sample size and relatively healthy population, imbalance in diabetes.

CONCLUSIONS

This small trial demonstrates successful cooperation between dentists and nephrologists and successful recruitment, treatment, and retention of dialysis patients with periodontitis. Larger studies with longer follow-up are needed to determine whether treatment can improve markers of inflammation and morbidity.

Cardiorenal syndrome: the emerging role of protein-bound uremic toxins

Cardiorenal syndrome is a condition in which a complex interrelationship between cardiac dysfunction and renal dysfunction exists. Despite advances in treatment of both cardiovascular and kidney disease, cardiorenal syndrome remains a major global health problem. Characteristic of the pathophysiology of cardiorenal syndrome is bidirectional cross-talk; mediators/substances activated by the disease state of 1 organ can play a role in worsening dysfunction of the other by exerting their biologically harmful effects, leading to the progression of the syndrome. Accumulation of uremic toxins is a hallmark of renal excretory dysfunction. Removal of some toxins by conventional dialysis is particularly problematic because of their high protein binding. In this review, we demonstrate that protein-bound uremic toxins may play an important role in progression of cardiovascular disease in the setting of chronic kidney disease. The highly protein-bound uremic toxin indoxyl sulfate has emerged as a potent toxin adversely affecting both the kidney and heart. Direct cardiac effects of this toxin have been recently demonstrated both in vitro and in vivo. Specifically, potent fibrogenic and prohypertrophic effects, as well as oxidative stress-inducing effects, appear to play a central role in both renal and cardiac pathology. Many of these adverse effects can be suppressed by use of a gut adsorbent, AST-120. Potential mechanisms underlying indoxyl sulfate-induced cardiorenal fibrosis are discussed. Future research and clinical implications conclude this review.

Effect of ultrapure dialysate on markers of inflammation, oxidative stress, nutrition and anemia parameters: a meta-analysis

BACKGROUND

Markers of inflammation are linked to malnutrition and confer an increased mortality risk in hemodialysis patients. Ultrapure dialysate might have a beneficial effect on markers of inflammation. We conducted a meta-analysis that examined the effect of ultrapure versus standard dialysate on markers of inflammation, oxidative stress, nutrition and anemia parameters.

METHODS

We performed a literature search using MEDLINE, Scopus, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov and scientific abstracts. Single-arm studies, nonrandomized and randomized controlled trials were included. We conducted random effects model meta-analyses to assess changes in the aforementioned outcomes.

RESULTS

We identified 16 single-arm studies, 2 crossover and 3 parallel-arm nonrandomized controlled trials and 5 crossover and 5 parallel-arm randomized controlled trials. In an analysis of 23 study arms or cohorts (n = 2221), ultrapure dialysate resulted in a significant decrease in C-reactive protein (-3.2 mg/L; 95% CI -4.6, -1.8; P < 0.001). Other markers of inflammation and oxidative stress displayed similar significant improvements. Ultrapure dialysate also resulted in a significant increase in serum albumin (0.11 g/dL; 95% CI 0.02, 0.19; P = 0.011) and hemoglobin (0.40 g/dL; 95% CI 0.06, 0.75; P = 0.022), and a decrease in the weekly erythropoietin dose (-273 units; 95% CI -420, -126; P < 0.001). The results remained significant in analyses restricted to controlled trials.

CONCLUSIONS

Use of ultrapure dialysate in hemodialysis patients results in a decrease in markers of inflammation and oxidative stress, an increase in serum albumin and hemoglobin and a decrease in erythropoietin requirement. Although improvement in these surrogate endpoints might confer a cardiovascular benefit, a large trial with hard clinical endpoints is required.

Predictors of acquired perforating dermatosis in uremic patients on hemodialysis: a case-control study

OBJECTIVES

The purpose of this study was to identify the predictors of acquired perforating dermatosis (APD) in patients on maintenance hemodialysis (HD).

METHODS

A case-control study was performed at our outpatient HD center between January 1, 2000 and March 31, 2011. Patients on HD with APD were matched (1 : 2) for gender and age with controls on HD. Conditional logistic regression was used to identify factors associated with APD.

RESULTS

A total of 19 patients with APD and 38 age and gender matched patients were enrolled in the study. Univariate logistic regression showed that APD was significantly associated with diabetes mellitus (DM), reduced levels of intact parathyroid hormone (iPTH) and albumin (Alb), reduced dialysis adequacy (Kt/V) and urea reduction rate (URR), and elevated levels of high-sensitivity C-reactive protein (hsCRP). Multivariate logistic regression identified reduced iPTH (hazard ratio (HR): 0.983; P = 0.026) and Alb (HR: 0.099; P = 0.047) and elevated hsCRP (HR: 1.210, P = 0.024) as risk factors for APD.

CONCLUSIONS

iPTH, hsCRP, and Alb are predictors for APD in HD patients.

Effect of statins on chronic inflammation and nutrition status in renal dialysis patients: a systematic review and meta-analysis

AIM

3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) may have an adjunctive effect on chronic inflammation and nutrition status in renal dialysis patients. Therefore, we performed a systematic review of randomized controlled trials to assess the effect of statins on chronic inflammation and nutrition status in dialysis patients.

METHODS

The randomized controlled trials (RCTs) of statins versus placebo or no treatment for renal dialysis patients were searched from PubMed, EMbase and Cochran Central Register of Controlled Trials. We screened relevant studies according to predefined inclusion and exclusion criteria, evaluated the quality of the included studies, and performed meta-analyses by using the Cochrane Collaboration's Revman 5.1 software.

RESULTS

We identified nine trials including 3098 patients. Meta-analysis showed statins can significantly decrease the serum C-reactive protein (CRP) (SMD, -0.54; 95% confidence interval (CI), -1.04 to -0.05; P = 0.03) and high sensitivity CRP (hs-CRP) level (SMD, -0.72; 95% CI, -1.14 to -0.31; P = 0.0007) of dialysis patients compared with that of the control group. However, statins did not differ significantly from the control group in increasing the serum Alb level (SMD, -0.13; 95% CI, -0.42 to 0.15; P = 0.37).

CONCLUSIONS

Statins can improve the chronic inflammation status reflected by the decreasing of serum CRP and hs-CRP levels, whereas there is no conclusive evidence that it can improve the nutrition status. However, this result needs to be further confirmed in more high-quality randomized clinical trials.

Hypoalbuminemia is an independent prognostic factor for overall survival in myelodysplastic syndromes

We hypothesized that hypoalbuminemia is an independent prognostic factor in patients with myelodysplastic syndromes (MDS). We analyzed records of 767 patients treated at Moffitt Cancer Center between January 2001 and December 2009 to evaluate the relationship between serum albumin (SA) at the time of presentation and overall survival (OS). Patients (median age of 69 years) were stratified into three groups based on SA concentration (≤3.5, 3.6-4.0, and >4.0 g/dL). Two-thirds of the patients had low or intermediate-1 International Prognostic Scoring System (IPSS)-based risk for MDS. Median OS by SA concentration of ≤3.5, 3.6-4.0, and >4.0 g/dL was 11, 23, and 34 months, respectively (P < 0.005), whereas rate of acute myeloid leukemia progression was highest in patients with low SA (≤3.5 g/dL). The SA level offered prognostic discrimination for outcomes within the lower and higher IPSS risk groups, as well as with the MD Anderson risk model. In multivariable analysis, SA was a significant independent co-variate for OS after adjustment for IPSS, age, serum ferritin, and transfusion dependence (hazard ratio = 0.8; 95% CI 0.6-0.9; P = 0.004). Our findings indicate that hypoalbuminemia is an independent prognostic biomarker that may serve as a surrogate representative of disease biology or comorbidities in patients with MDS.

Longer dialysis session length is associated with better intermediate outcomes and survival among patients on in-center three times per week hemodialysis: results from the Dialysis Outcomes and Practice Patterns Study (DOPPS)

BACKGROUND

Longer dialysis session length (treatment time, TT) has been associated with better survival among hemodialysis (HD) patients. The impact of TT on clinical markers that may contribute to this survival advantage is not well known.

METHODS

Using data from the international Dialysis Outcomes and Practice Patterns Study, we assessed the association of TT with clinical outcomes using both standard regression analyses and instrumental variable approaches. The study included 37,414 patients on in-center HD three times per week with prescribed TT from 120 to 420 min.

RESULTS

Facility mean TT ranged from 214 min in the USA to 256 min in Australia-New Zealand. Accounting for country effects, mortality risk was lower for patients with longer TT {hazard ratio for every 30 min: all-cause mortality: 0.94 [95% confidence interval (CI): 0.92-0.97], cardiovascular mortality: 0.95 (95% CI: 0.91-0.98) and sudden death: 0.93 (95% CI: 0.88-0.98)}. Patients with longer TT had lower pre- and post-dialysis systolic blood pressure, greater intradialytic weight loss, higher hemoglobin (for the same erythropoietin dose), serum albumin and potassium and lower serum phosphorus and white blood cell counts. Similar associations were found using the instrumental variable approach, although the positive associations of TT with weight loss and potassium were lost.

CONCLUSIONS

Favorable levels of a variety of clinical markers may contribute to the better survival of patients receiving longer TT. These findings support longer TT prescription in the setting of in-center, three times per week HD.

Nutritional Intervention Incorporating Expedited 10 g Protein Counter (EP-10) to Improve the Albumin and Transferrin of Chronic Hemodialysis Patients

Objective. The expedited 10 g protein counter (EP-10) is a quick and valid clinical tool for dietary protein quantification. This study aims to assess the clinical effectiveness of the EP-10 in improving serum albumin and transferrin in chronic hemodialysis patients. Methods. Forty-five patients with low serum albumin (<38 g/L) were enrolled in this study. Parameters measured included dry weight, height, dietary intake, and levels of serum albumin, transferrin, potassium, phosphate, and kinetic modeling (Kt/V). The nutritional intervention incorporated the EP-10 in two ways (1) to quantify protein intake of patients and (2) to educate patients to meet their protein requirements. Mean values of the nutritional parameters before and after intervention were compared using paired t-test. Results. Three months after nutritional intervention, mean albumin levels increased significantly from 32.2 ± 4.8 g/L to 37.0 ± 3.2 g/L (P < 0.001). Thirty-eight (84%) patients showed an increase in albumin levels, while two (4%) maintained their levels. Of the thirty-six (80%) patients with low transferrin levels (<200 mg/dL), 28 (78%) had an increase and two maintained their levels after intervention. Mean transferrin levels increased significantly from 169.4 ± 39.9 mg/dL to 180.9 ± 38.1 mg/dL (P < 0.05). Conclusion. Nutritional intervention incorporating the EP-10 method is able to make significant improvements to albumin and transferrin levels of chronic hemodialysis patients.

Shorter length dialysis sessions are associated with increased mortality, independent of body weight

Hemodialysis patients have high rates of mortality that may be related to aspects of the dialytic procedure. In prior studies, shorter length dialysis sessions have been associated with decreased survival, but these studies may have been confounded by body size differences. Here we tested whether in-center three-times-weekly hemodialysis patients with adequate urea clearances but shorter dialysis session length is associated with mortality independent of body size. Data were taken from a large national cohort of patients from a large dialysis organization undergoing three-times-weekly in-center hemodialysis. In the primary analysis, patients with prescribed dialysis sessions greater and less than 240 min were pair-matched on post-dialysis weight as well as on age, gender, and vascular access type. Compared to prescribed longer dialysis sessions, session lengths less than 240 min were significantly associated with increased all-cause mortality (adjusted hazard ratio 1.26). The association was consistent across strata of age, gender, and dialysis post-weight. Secondary analyses found a dose-response between prescribed session length and survival. Thus, among patients with adequate urea clearance, shorter dialysis session lengths are associated with increased mortality independent of body weight.

Chapter 7 Adequacy of haemodialysis in UK adult patients in 2010: national and centre-specific analyses

BACKGROUND

Outcome in patients treated with haemodialysis (HD) is influenced by the delivered dose of dialysis. The UK Renal Association (RA) publishes clinical practice guidelines which include recommendations for dialysis dose. The urea reduction ratio (URR) is a widely used measure of dialysis dose.

AIM

To determine the extent to which patients received the recommended dose of HD in the UK.

METHODS

All seventy-two UK renal centres submitted data to the UK Renal Registry (UKRR). Two groups of patients were included in the analyses: the prevalent patient population on 31st December 2010 and the incident patient population for 2010. Centres returning data on <50% of their patient population or centres with <20 patients were excluded from centre-specific comparisons.

RESULTS

Data regarding URR were available from 64 renal centres in the UK. Forty nine centres provided URR data on more than 90% of prevalent patients. The proportion of patients in the UK who met the UK clinical practice guideline for URR (>65%) increased from 56% in 1998 to 86% in 2010. There was persistent variation observed between centres, with 19 centres attaining the RA clinical practice guideline in >90% of patients and 39 centres attaining the guideline in 70-90%. The overall proportion of prevalent patients with a URR >65% has continued to improve over time.

CONCLUSIONS

The delivered dose of HD for patients with established renal failure has increased over the last decade. Whilst the majority of UK patients achieved the target URR there was considerable variation between centres in the percentage of patients achieving the guideline.

Reverse iontophoresis of urea in health and chronic kidney disease: a potential diagnostic and monitoring tool?

BACKGROUND

Patients with chronic kidney disease (CKD) need regular monitoring, usually by blood urea and creatinine measurements, needing venepuncture, frequent attendances and a healthcare professional, with significant inconvenience. Noninvasive monitoring will potentially simplify and improve monitoring. We tested the potential of transdermal reverse iontophoresis of urea in patients with CKD and healthy controls.

METHODS

Using a MIC 2(®) Iontophoresis Controller, reverse iontophoresis was applied on the forearm of five healthy subjects (controls) and 18 patients with CKD for 3-5 h. Urea extracted at the cathode was measured and compared with plasma urea.

RESULTS

Reverse iontophoresis at 250 μA was entirely safe for the duration. Cathodal buffer urea linearly correlated with plasma urea after 2 h (r = 0·82, P < 0·0001), to 3·5 h current application (r = 0·89, P = 0·007). The linear equations y = 0·24x + 1 and y = 0·21x + 4·63 predicted plasma urea (y) from cathodal urea after 2 and 3 h, respectively. Cathodal urea concentration in controls was significantly lower than in patients with CKD after a minimum current application of 2 h (P < 0·0001), with the separation between the two groups becoming more apparent with longer application (P = 0·003). A cathodal urea cut-off of 30 μM gave a sensitivity of 83·3% and positive predictive value of 87% CKD. During haemodialysis, the fall in cathodal urea was able to track that of blood urea.

CONCLUSION

Reverse iontophoresis is safe, can potentially discriminate patients with CKD and healthy subjects and is able to track blood urea changes on dialysis. Further development of the technology for routine use can lead to an exciting opportunity for its use in diagnostics and monitoring.

Blood color is influenced by inflammation and independently predicts survival in hemodialysis patients: quantitative evaluation of blood color

Blood color of dialysis patients can be seen routinely. Darkened blood color is often observed in critically ill patients generally because of decreased oxygen saturation, but little is known about the other factors responsible for the color intensity. In addition, quantitative blood color examination has not been performed yet. Therefore, no one has evaluated the predictive power of blood color. The aim of this study was to evaluate if blood color darkness reflects some medical problems and is associated with survival disadvantage. Study design is a prospective cohort study. One hundred sixty-seven patients were enrolled in this study. Quantification of blood color was done using a reflected light colorimeter. Demographic and clinical data were collected to find out the factors that can be related to blood color. Follow-ups were performed for 2 years to analyze the risk factors for their survival. Regression analysis showed that C-reactive protein and white blood cell count were negatively correlated with blood color. In addition, blood color was positively correlated with mean corpuscular hemoglobin concentration and serum sodium concentration as well as blood oxygen saturation. During a follow-up, 34 (20.4%) patients died. Cox regression analysis revealed that darkened blood color was an independent significant risk factor of mortality in hemodialysis patients as well as low albumin and low Kt/V. These results suggest that inflammation independently affects blood color and quantification of blood color is useful to estimate prognosis in patients undergoing hemodialysis. It is possible that early detection of blood color worsening can improve patients' survival.

The controversies of diagnosing and treating hypertension among hemodialysis patients

This review discusses 10 current controversies regarding the dialysis patient with hypertension. The clinician is faced with a dilemma at the bedside on how to evaluate blood pressure and treat this condition in a patient on long-term hemodialysis. The evidence base to give firm recommendations is thin, but the epidemiological evidence tells us to do nothing. This appears to be an incorrect strategy, at least based on what we know today. Evaluating home BP in every dialysis patient, evaluating volume status on a regular basis, and treating hypertension predominantly with nonpharmacological strategies are worthwhile.

Acute kidney injury and chronic kidney disease: an integrated clinical syndrome

The previous conventional wisdom that survivors of acute kidney injury (AKI) tend to do well and fully recover renal function appears to be flawed. AKI can cause end-stage renal disease (ESRD) directly, and increase the risk of developing incident chronic kidney disease (CKD) and worsening of underlying CKD. In addition, severity, duration, and frequency of AKI appear to be important predictors of poor patient outcomes. CKD is an important risk factor for the development and ascertainment of AKI. Experimental data support the clinical observations and the bidirectional nature of the relationships between AKI and CKD. Reductions in renal mass and nephron number, vascular insufficiency, cell cycle disruption, and maladaptive repair mechanisms appear to be important modulators of progression in patients with and without coexistent CKD. Distinction between AKI and CKD may be artificial. Consideration should be given to the integrated clinical syndrome of diminished GFR, with acute and chronic stages, where spectrum of disease state and outcome is determined by host factors, including the balance of adaptive and maladaptive repair mechanisms over time. Physicians must provide long-term follow-up to patients with first episodes of AKI, even if they presented with normal renal function.

Outcomes associated with intradialytic oral nutritional supplements in patients undergoing maintenance hemodialysis: a quality improvement report

BACKGROUND

Insufficient clinical data exist to determine whether provision of oral nutritional supplements during dialysis can improve survival in hypoalbuminemic maintenance hemodialysis patients.

STUDY DESIGN

Retrospective matched-cohort study.

SETTING & PARTICIPANTS

All oral nutritional supplement program-eligible in-center maintenance hemodialysis patients with albumin level ≤3.5 g/dL in quarter 4 of 2009 without oral nutritional supplements in the prior 90 days at Fresenius Medical Care, North America facilities.

QUALITY IMPROVEMENT PLAN

Monitored intradialytic oral nutritional supplements were provided to eligible maintenance hemodialysis patients upon physician order, to continue for a year or until serum albumin level was ≥4.0 g/dL.

OUTCOME

Mortality (including deaths and withdrawals), followed up until December 31, 2010.

MEASUREMENTS

Both an intention-to-treat (ITT) and an as-treated analysis was performed using a 1:1 geographic region and propensity score-matched study population (using case-mix, laboratory test, access type, 30-day prior hospitalization, and incident patient status) comparing patients treated with intradialytic oral nutritional supplements with usual-care patients. Cox models were constructed, unadjusted and adjusted for facility standardized mortality ratio and case-mix and laboratory variables.

RESULTS

The ITT and as-treated analyses both showed lower mortality in the oral nutritional supplement group. The conservative ITT models with 5,227 matched pairs had 40% of controls subsequently receiving oral nutritional supplements after January 1, 2010 (because many physicians delayed participation), with comparative death rates of 30.1% versus 30.4%. The corresponding as-treated (excluding crossovers) death rates for 4,289 matched pairs were 30.9% versus 37.3%. The unadjusted ITT mortality HR for oral nutritional supplement use was 0.95 (95% CI, 0.88-1.01), and the adjusted HR was 0.91 (95% CI, 0.85-0.98); the corresponding as-treated HRs were 0.71 (95% CI, 0.66-0.76) and 0.66 (95% CI, 0.61-0.71) before and after adjustment, respectively.

LIMITATIONS

Limited capture of oral nutritional supplement intake outside the facility and potential residual confounding from unmeasured variables, such as dietary intake.

CONCLUSIONS

Maintenance hemodialysis patients with albumin levels ≤3.5 g/dL who received monitored intradialytic oral nutritional supplements showed survival significantly better than similar matched patient controls, with the as-treated analysis highlighting the potentially large effect of this strategy in clinical practice.

Mortality and health-related quality of life in prevalent dialysis patients: Comparison between 12-items and 36-items short-form health survey

BACKGROUND

To assess health- related quality of life (HRQOL) with SF-12 and SF-36 and compare their abilities to predict mortality in chronic dialysis patients, after adjusting for traditional risk factors.

METHODS

The Short-Form Health Survey (SF-36) with the embedded SF-12 was applied in 301 dialysis patients cross-sectionally. Physical and mental component summary (PCS-36, MCS-36, PCS-12, and MCS-12) scores were calculated. Clinical and demographic data were collected. Mortality (followed for up to 4.5 years) was analyzed with Kaplan Meier plots and Cox proportional hazards, after censoring for renal transplantation. Exclusion factors were observation time <2 months (n = 21) and missing component summary scores (n = 10 for SF-36; n = 28 for SF-12), thus 252 patient were included in the analyses.

RESULTS

In 252 patients (60.2 ± 15.5 years, 65.9% males, dialysis vintage 9.0, IQR 5.0-23.0 months), mortality during follow-up was 33.7%.(85 deaths). Significant correlations were observed between PCS-36 and PCS-12 (ρ = 0.93, p < 0.001) and between MCS-36 and MCS-12 (ρ = 0.95, p < 0.001). Mortality rate was highest in patients in the lowest quartile of PCS-12 (χ² = 15.3, p = 0.002) and PCS-36 (χ² = 16.7, p = 0.001). MCS was not associated with mortality. Adjusted hazard ratios for mortality were 2.5 (95% CI 1.0-6.3, PCS-12) and 2.7 (1.1 - 6.4, PCS-36) for the lowest compared with the highest ("best perceived") quartile of PCS.

CONCLUSION

Compromised HRQOL is an independent predictor of poor outcome in dialysis patients. The SF-12 provided similar predictions of mortality as SF-36, and may serve as an applicable clinical tool because it requires less time to complete.

Novel dialysis modalities: do we need new metrics to optimize treatment?

Delivered dose of hemodialysis has long been an important predictor of mortality. The limitations of conventional hemodialysis treatments have led to a renewed interest in more frequent and longer hemodialysis treatments. As alternative hemodialysis schedules have become more prevalent, a need for modified metrics to measure adequacy has emerged. In addition, there is an interest in finding measures of hemodialysis adequacy that are more reliable in certain subgroups of patients, such as women, ethnic minority groups, or people with small body size. Finally, extended hemodialysis schedules suggest a need for metrics that can measure the clearance of solutes other than urea, such as middle-size molecules, and solutes for which clearance depends on intercompartmental transport across membranes. New metrics to quantify clearance in extended and alternate hemodialysis schedules are needed. As new metrics are developed, it is anticipated that they will also contribute to more accurate assessments of associations between clinical outcomes and delivered dose of dialysis in more intensive, nontraditional hemodialysis schedules. This review provides a historical prospective of dialysis dose and adequacy and describes the need for new metrics from both solute type and dialysis dose prospective as alternative hemodialysis schedules have emerged and become more prevalent.