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

Nutrition, inflammation and chronic kidney disease

PURPOSE OF REVIEW

Protein-energy wasting and chronic inflammation are important comorbid conditions that predict poor clinical outcome in patients with advanced chronic kidney disease. The current article aims to provide a brief overview of the etiology and nutritional consequences of chronic inflammation with an outline of potential treatment options.

RECENT FINDINGS

The exact mechanisms leading to these unfavorable conditions are not fully elucidated and are most likely multifactorial. Irrespective of the specific etiologic mechanisms, it appears that the common pathway for all the metabolic derangements is related to exaggerated protein degradation relative to protein synthesis. Several studies suggest that chronic inflammation can predispose advanced chronic kidney disease patients to a catabolic state leading to worsening of protein-energy wasting by both increasing protein breakdown and decreasing protein synthesis. Chronic administration of nutritional supplementation, both parenterally and orally, improves nutritional status even in inflamed hemodialysis patients. Several pilot studies indicate that antiinflammatory intervention can also improve the metabolic and nutritional profiles.

SUMMARY

While a single common etiology has not been identified in this complex process, nutritional and antiinflammatory interventions can provide potential treatment options to improve the high mortality and morbidity in patients with advanced chronic kidney disease.

Chronic kidney disease and its complications

Chronic kidney disease (CKD) is a complex disease affecting more than 20 million individuals in the United States. Progression of CKD is associated with a number of serious complications, including increased incidence of cardiovascular disease, hyperlipidemia, anemia, and metabolic bone disease. CKD patients should be assessed for the presence of these complications and receive optimal treatment to reduce their morbidity and mortality. A multidisciplinary approach is required to accomplish this goal.

Lithium heparinised blood-collection tubes give falsely low albumin results with an automated bromcresol green method in haemodialysis patients

BACKGROUND

The aim of this study was to investigate the cause of markedly low albumin values determined by a bromcresol green (BCG) method in patients on haemodialysis.

METHODS

Serum and heparinised plasma from haemodialysis patients and normal controls were collected. Albumin was measured using Beckman bromcresol purple (BCP) and Roche BCG methods on the Beckman Synchron LX20.

RESULTS

The albumin in heparinised plasma determined by a BCG method was 33.3% lower than that of the BCP method in a haemodialysis patient. The albumin values determined by the BCP method were comparable to those measured by immunonephelometric analysis for this patient. Significantly lower albumin levels were also observed in lithium heparin plasma by a BCG method compared to the BCP method in both non-renal patients (31.2+/-3.8 vs. 34.1+/-4.1 g/L, p<0.001, n=30) and haemodialysis patients (28.6+/-3.5 vs. 32.8+/-3.7 g/L, p<0.001, n=30). This negative bias was directly correlated with heparin concentrations in the plasma. The BCP method did not show this dose-dependent bias.

CONCLUSIONS

Lithium heparin plasma can cause falsely low albumin values by an automated BCG method and the suitability of lithium heparin blood tubes should be carefully assessed for haemodialysis patients. The BCP method is free of this bias.

Dialysis adequacy and nutritional status of hemodialysis patients

To characterize the nutritional status of renal failure patients and its relationship with hemodialysis adequacy measured by Kt/V, a study was carried out with a population of 44 adult patients with renal failure and mean age 51+/-15 years. Anthropometric data, such as dry weight, height, arm circumference, triceps skinfold thickness, mid-arm muscle circumference, and body mass index were assessed, and biochemical tests were conducted for urea, potassium, creatinine, serum albumin, and phosphorus levels, in addition to hemogram and quarterly urea reduction rate average (Kt/V). In order to evaluate calorie intake, a dietary questionnaire on habitual daily food ingestion was administered, taking into consideration the hemodialysis date. The patients were divided into 2 separate groups for the statistical analysis, with 50% of the patients in each group: A (Kt/V<1.2) and B (Kt/V>1.2). The data were tabulated as mean and standard deviation, with differences tested by Student's t test. The correlations between variables were established by the coefficient p of Pearson. Most of the patients (43%) were considered eutrophic, based on the BMI, and presented inadequate calorie intake, corresponding to 88.5+/-24% (30.8 kcal/kg actual weight) of the total energy required and adequate protein intake, reaching 109.9+/-40% of the recommended daily allowance (1.24 g/kg of actual weight). There was a correlation of Kt/V with anthropometric parameters such as body mass index, arm circumference, and mid-arm muscle circumference. The biochemical parameters related to dialysis adequacy were albumin, ferritin, and urea (predialysis). Well-dialyzed patients presented better levels of serum albumin. There was an influence of gender and age on correlations of the analyzed variables. Female and younger patients presented better dialysis adequacy. The dialysis adequacy was related to the nutritional status and influenced by the protein intake and body composition. Gender and age had an important influence in the dialysis adequacy, as men presented lower dialysis adequacy and younger adults presented better dialysis adequacy. Further research is necessary to understand better how to facilitate effective and efficient techniques for the nutritional status assessment of hemodialysis patients.

Serum albumin level and risk for mortality and hospitalization in adolescents on hemodialysis

BACKGROUND AND OBJECTIVES

National Kidney Foundation Dialysis Outcomes Quality Initiative practice guidelines recommend serum albumin > or = 4.0 g/dl for adults who are on hemodialysis. There is no established pediatric target for albumin and little evidence to support use of adult guidelines. This study examined the association between albumin and risk for death and hospitalization in adolescents who are on hemodialysis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This retrospective cohort study linked data on patients aged 12 to 18 yr in 1999 and 2000 from the Centers for Medicare and Medicaid Services' End Stage Renal Disease Clinical Performance Measures Project with 4-yr hospitalization and mortality records in the United States Renal Data System. Albumin was categorized as < 3.5/3.2, > or = 3.5/3.2 and < 4.0/3.7, and > or = 4.0/3.7 g/dl.

RESULTS

Of 675 adolescents, 557 were hospitalized and 50 died. Albumin > or = 4.0/3.7 g/dl was associated with male gender, Hispanic ethnicity, and higher hemoglobin level. Those with albumin > or = 4.0/3.7 g/dl had fewer deaths per 100 patient-years and fewer hospitalizations per time at risk. In multivariate analysis, patients with albumin > or = 4.0/3.7 g/dl had 57% decreased risk for death. Poisson regression showed progressive decrease in hospitalization risk as albumin level increased; however, confidence intervals were similar between albumin > or = 4.0/3.7 g/dl and albumin > or = 3.5/3.2 and < 4.0/3.7 g/dl.

CONCLUSIONS

This study demonstrates decreased mortality and hospitalization risk with albumin > or = 3.5/3.2 g/dl and suggests that adolescent hemodialysis patients who are able to achieve serum albumin > or = 4.0/3.7 g/dl may have the lowest mortality risk.

Albumin levels predict survival in patients with systolic heart failure

BACKGROUND

Hypoalbuminemia is associated with poor prognosis in patients with certain chronic diseases, such as end-stage renal disease and cancer. Although low serum albumin is common in patients with heart failure (HF), the relationship between albumin and HF prognosis has not been well characterized. This study investigated the effect of serum albumin level on survival in patients with advanced HF.

METHODS

We analyzed 1726 systolic HF patients (age 52 +/- 13 years, ejection fraction [EF] 23% +/- 7%) followed at a university HF center. Albumin level was determined at initial referral. Patients were divided by into groups based on presence of hypoalbuminemia (< or = 3.4 g/dL). Mean albumin was 3.8 +/- 0.6 g/dL, and 25% of patients had hypoalbuminemia.

RESULTS

Patients with and without low albumin levels were similar in age, HF etiology, and EF. Hypoalbuminemia was associated with higher New York Heart Association (NYHA) class, higher serum urea nitrogen, creatinine level, C-reactive protein, and B-type natriuretic peptide but lower levels of sodium, hemoglobin, and cholesterol. In patients with BMI < 25 kg/m(2), 27% had albumin < or = 3.4 g/dL, compared to 22% of those with BMI > or = 25 kg/m(2) (P < .01). One-year survival was 66% in patients with and 83% in those without hypoalbuminemia (P < .0001). Risk-adjusted hazard ratios for 1- and 5-year mortality were 2.2 (1.4-3.3) and 2.2 (1.4-3.2), respectively.

CONCLUSIONS

Hypoalbuminemia is common in HF and is independently associated with increased risk of death in HF. Further investigation of pathophysiologic mechanisms underlying hypoalbuminemia in HF is warranted.

The effect of increasing dialysis dose in overweight hemodialysis patients on quality of life: a 6-week randomized crossover trial

BACKGROUND

Using standard hemodialysis regimens, overweight patients often do not reach Kidney Disease Outcomes Quality Initiatives (KDOQI) Kt/V targets, and this has been associated with lower health-related quality of life (HRQL). Whether increasing dialysis adequacy in large patients not achieving KDOQI targets improves HRQL is unknown.

STUDY DESIGN

Randomized blinded crossover study.

SETTING & PARTICIPANTS

Overweight (>80 kg) underdialyzed patients from 6 dialysis units in 2 Canadian dialysis programs.

INTERVENTIONS

Six-week treatment periods with a standard dialysis regimen (4 hours 3 times weekly) and 3 augmented regimens: 4.5 hours of hemodialysis, 4 hours of hemodialysis with increased dialysate flow, and 4 hours of hemodialysis with 2 dialyzers in parallel.

OUTCOMES & MEASUREMENTS

The End-Stage Renal Disease Symptom domain of the Kidney Disease Quality-of-Life Short-Form questionnaire (primary outcome) and the Health Utilities Index Mark 2 (secondary outcome).

RESULTS

We enrolled 18 patients (mean weight, 109.7 +/- 16.2 [SD] kg); 12 completed all 4 regimens. Mean Kt/Vs during the study were 1.27 (95% confidence interval [CI], 1.19 to 1.35), 1.41 (95% CI, 1.32 to 1.50), 1.31 (95% CI, 1.22 to 1.39), and 1.41 (95% CI, 1.33 to 1.49) for patients receiving standard dialysis, 4.5 hours of hemodialysis, hemodialysis with increased dialysate flow, and hemodialysis with 2 dialyzers, respectively. Kidney Disease Quality-of-Life End-Stage Renal Disease Symptom domain and Health Utilities Index Mark 2 scores were 75.9 (95% CI, 70.7 to 81.2) and 0.69 (95% CI, 0.56 to 0.81) for patients receiving standard dialysis, respectively. These did not differ when patients received the 3 augmented dialysis regimens (P = 0.2 and P = 0.5, respectively).

LIMITATIONS

Small sample size and inability to fully blind patients to the treatment they were receiving.

CONCLUSION

Improving hemodialysis adequacy for large underdialyzed patients did not lead to improved HRQL. Our findings suggest that augmentation of the dialysis regimen is not required for these patients in the absence of overt uremic symptoms.

A review of albumin binding in CKD

Hypoalbuminemia is associated with excess mortality in patients with kidney disease. Albumin is an important oxidant scavenger and an abundant carrier protein for numerous endogenous and exogenous compounds. Several specific binding sites for anionic, neutral, and cationic ligands were described. Overall, the extent of binding depends on the ligand and albumin concentration, albumin-binding affinity, and presence of competing ligands. Chronic kidney disease affects all these determinants. This may result in altered pharmacokinetics and increased risk of toxicity. Renal clearance of albumin-bound solutes mainly depends on tubular clearance. Dialytic clearance by means of conventional hemodialysis/hemofiltration and peritoneal dialysis is limited. Other epuration techniques combining hemodialysis with adsorption have been developed. However, the benefit of these techniques remains to be proved.

Survival during renal replacement therapy among African Americans infected with HIV type 1 in urban Baltimore, Maryland

BACKGROUND

African Americans with human immunodeficiency virus type 1 (HIV-1) infection and kidney disease are at increased risk of end-stage renal disease requiring renal replacement therapy (RRT), particularly in urban areas with high rates of poverty and injection drug use. It is unknown how the widespread use of highly active antiretroviral therapy (HAART) has affected survival during RRT in this vulnerable population.

METHODS

African American patients infected with HIV-1 who required RRT were identified from 2 cohorts that included 4509 Africans Americans infected with HIV-1 who were recruited during the period 1988-2004 in Baltimore, Maryland. Survival after initiation of RRT was compared for those who initiated treatment in the pre-HAART and the HAART eras using Kaplan-Meier curves. Cox proportional hazards regression analysis was used to adjust for potential confounders.

RESULTS

RRT was initiated in 162 patients (3.6%) during 10.6 years of follow-up (119 during the HAART era). Compared with patients who started RRT in the pre-HAART era, those in the HAART era were older (P<.001) and more likely to have CD4 cell counts of <or=200 cells/mm(3) (P=.01). A total of 126 patients (78%) died during follow-up; among those who initiated RRT during the HAART era, 87 deaths occurred (73%). Median survival time in the pre-HAART era was 22.4 months (95% confidence interval [CI], 9.3-30.7); during the HAART era, it was 19.9 months (95% CI, 14.7-26.5; P=.94). In the multiple Cox regression model, factors independently associated with increased mortality included age (hazard ratio [HR], 1.30; 95% CI, 1.06-1.60; P=.01), lower serum albumin level (HR, 0.72; 95% CI, 0.57-0.91; P<.007), lower CD4 cell count (HR, 0.90; 95% CI, 0.82-0.99; P<.03), and the lack of HAART (HR, 0.52; 95% CI, 0.33-0.82; P=.005).

CONCLUSIONS

Older age, lower serum albumin level, lower CD4 cell count, and the lack of HAART are independent predictors of poor survival among African Americans infected with HIV-1 undergoing RRT in a resource-limited urban area. RRT survival was similar in the pre-HAART and HAART eras, likely reflecting inadequate HIV treatment in this population.

Impact of growth hormone and dehydroepiandrosterone on protein metabolism in glucocorticoid-treated patients

CONTEXT

Chronic pharmacological glucocorticoid (GC) use causes substantial morbidity from protein wasting. GH and androgens are anabolic agents that may potentially reverse GC-induced protein loss.

OBJECTIVE

Our objective was to assess the effect of GH and dehydroepiandrosterone (DHEA) on protein metabolism in subjects on long-term GC therapy.

DESIGN

This was an open, stepwise GH dose-finding study (study 1), followed by a randomized cross-over intervention study (study 2).

SETTING

The studies were performed at a clinical research facility.

PATIENTS AND INTERVENTION

In study 1, six subjects (age 69+/-4 yr) treated with long-term (>6 months) GCs (prednisone dose 8.3+/-0.8 mg/d) were studied before and after two sequential GH doses (0.8 and 1.6 mg/d) for 2 wk each. In study 2, 10 women (age 71+/-3 yr) treated with long-term GCs (prednisone dose 5.4+/-0.5 mg/d) were studied at baseline and after 2-wk treatment with GH 0.8 mg/d, DHEA 50 mg/d, or GH and DHEA (combination treatment).

MAIN OUTCOME MEASURE

Changes in whole body protein metabolism were assessed using a 3-h primed constant infusion of 1-[13C]leucine, from which rates of leucine appearance, leucine oxidation, and leucine incorporation into protein were estimated.

RESULTS

In study 1, GH 0.8 and 1.6 mg/d significantly reduced leucine oxidation by 19% (P=0.03) and 31% (P=0.02), and increased leucine incorporation into protein by 10% (P=0.13) and 19% (P=0.04), respectively. The lower GH dose did not cause hyperglycemia, whereas GH 1.6 mg/d resulted in fasting hyperglycemia in two of six subjects. In study 2, DHEA did not significantly change leucine metabolism alone or when combined with GH. Blood glucose was not affected by DHEA.

CONCLUSION

GH, at a modest supraphysiological dose of 0.8 mg/d, induces protein anabolism in chronic GC users without causing diabetes. DHEA 50 mg/d does not enhance the effect of GH. GH may safely prevent or reverse protein loss induced by chronic GC therapy.

How to reconcile conventional and altered risk factor patterns in dialysis patients

Epidemiological relationships between risk factors and outcome in patients with chronic kidney failure (CKF), including individuals with end-stage kidney failure, can be categorized into three types: risk factor relationships that are similar to those observed in the general population; risk factor relationships that differ from those observed in the general population; and risk factor patterns that are difficult or not possible to compare to the general population, possibly because such risk factors have not been studied or are not capable of being studied in normal individuals. These latter risk factor patterns may or may not be different from what might commonly be anticipated. It is recommended that risk factor relationships in CKF patients which differ from those observed in the general population should be referred to as altered risk factor patterns (ARFPs). The causes for ARFPs include protein-energy wasting and inflammatory disorders, which occur commonly in patients with CKF. Epidemiological and other evidence is presented suggesting that the ARFPs may also have other causes. Since ARFPs are common in CKF, it is important to understand the causes and appropriate therapeutic goals concerning these risk factors. Studies, including interventional clinical trials, are indicated to ascertain the causes of ARFPs and the therapeutic targets for these risk factors for individuals with chronic kidney disease and CKF.

Loss of fractal heart rate dynamics in depressive hemodialysis patients

OBJECTIVE

To assess the relationship between depression, reduced heart rate (HR) variability, and altered HR dynamics among patients with end-stage renal disease who are receiving hemodialysis (HD) therapy.

METHODS

We analyzed the 24-hour electrocardiograms of 119 outpatients receiving chronic HD. HR variability was quantified with the standard deviation of normal-to-normal R-R intervals, the triangular index, and the powers of the high- (HF), low- (LF), very-low (VLF), and ultra-low frequency (ULF) components. Nonlinear HR dynamics was assessed with the short-term (alpha(1)) and long-term (alpha(2)) scaling exponents of the detrended fluctuation analysis and approximate entropy. The depression level was assessed using the Beck Depression Inventory, Second Edition (BDI-II). HR variability and dynamics measurements were compared by gender, diabetes, and depression with adjustment for age and serum albumin concentration.

RESULTS

Most indices of HR variability and dynamics were negatively correlated with age, serum albumin concentration, depression score, and were lower in women and patients with diabetes. The alpha(2) was inversely associated with these variables. Depressed men had significantly lower HF, LF, VLF, and marginally lower ULF than nondepressed persons after adjustment for diabetes and other covariates; no difference in depression was observed in women. The alpha(2) showed marginally significant difference in depression independent from gender and diabetes.

CONCLUSIONS

Among the patients who received HD, depression is associated with reduced HR variability and loss of fractal HR dynamics. However, the influence of depression on HR variability may vary by gender and physiological backgrounds. Further prospective studies are necessary to confirm their association with poor prognosis.

Hypoalbuminaemia--a marker of cardiovascular disease in patients with chronic kidney disease stages II-IV

Cardiovascular disease (CVD) is a major cause of morbidity and mortality in patients with chronic kidney disease (CKD) patients. Serum albumin, a negative acute-phase reactant and marker for underlying inflammation and/or malnutrition, is an independent predictor of CVD and mortality in CKD VI patients. Such an association in patients with less severe CKD is not well established. We conducted a cross sectional study of all CKD II-IV patients attending the nephrology clinic (N=376; mean age: 57+/-17 years; GFR: 47+/-20 mL/min/1.73 m(2); females 48%; blacks 15%; diabetics 27%; hypertensive 79%). Laboratory and clinical data including risk factors and evidence of CVD were obtained at the point of the most recent visit. The association between risk factors and CVD was evaluated by logistic regression. In the simple logistic regression model, age (p<0.0001), sex (P= 0.02), hypertension (P<0.0001), diabetes (P<.0001), dyslipidemia (p=.01), and serum albumin (p<.0001) were found to be statistically significant. Serum albumin was found to be an independent predictor (p=0.04) of CVD by multiple logistic regression analysis using the above risk factor variables.

IN CONCLUSION

a) hypoalbuminaemia is an independent predictor of CVD in early CKD stages; b) hypoalbuminaemia may be used to identify the population at higher risk for CVD.

Effect of electronic patient record use on mortality in End Stage Renal Disease, a model chronic disease: retrospective analysis of 9 years of prospectively collected data

Background

In chronic disease, health information technology promises but has yet to demonstrate improved outcomes and decreased costs. The main aim of the study was to determine the effects on mortality and cost of an electronic patient record used in daily patient care in a model chronic disease, End Stage Renal Disease, treated by chronic maintenance hemodialysis. Dialysis treatment is highly regulated, and near uniform in treatment modalities and drugs used.

Methods

The particular electronic patient record, patient-centered and extensively coded, was used first in patient care in 3 dialysis units in New York, NY in 1998, 1999, and 2000. All data were stored "live"; none were archived. By December 31, 2006, the patients had been treated by maintenance hemodialysis for a total of 3924 years. A retrospective analysis was made using query tools embedded in the software. The United States Renal Data System dialysis population served as controls. In all there were 1790 patients, with many underlying primary diseases and multiple comorbid conditions affecting many organ systems. Year by year mortality, hospital admissions, and staffing were analyzed, and the data were compared with national data compiled by the United States Renal Data System.

Results

Analyzed by calendar year after electronic patient record implementation, mortality decreased strikingly. In years 3–9 mortality was lower than in years 1–2 by 23%, 48%, and 34% in the 3 units, and was 37%, 37%, and 35% less than that reported by the United States Renal Data System. Clinical staffing was 25% fewer per 100 patients than the national average, thereby lowering costs.

Conclusion

To our knowledge, this is the first demonstration that an electronic patient record, albeit of particular design, can have a favorable effect on outcomes and cost in chronic disease. That the population studied has many underlying diseases affecting all organ systems suggests that the electronic patient record design may enable application to many fields of medical practice.

Comparison of classical and non-classical cardiovascular risk factors influencing the patency of native arteriovenous fistulas after percutaneous transluminal angioplasty therapy among haemodialysis patients

OBJECTIVE

To evaluate the classical and non-classical cardiovascular risk factors that effect patency of native arteriovenous fistulas (AVF) in end stage renal disease (ESRD) patients who are undergoing regular haemodialysis treatment and have a percutaneous transluminal angioplasty (PTA) procedure.

METHODS

All PTAs performed between 1 October 2002 and 30 September 2004 were identified from case notes and the computerised database and follow up to 31 March 2005. The definition of patency of AVF after PTA was including primary or secondary patencies. Risks were analysed to assess the influence on survival following PTAs of age, sex, serum cholesterol, serum triglyceride, diabetes, use of aspirin, current smoking and hypertension, serum albumin, serum calcium-phosphate product, intact parathyroid hormone (I-PTH), and urea reduction ratio (URR).

RESULTS

The patency rate of AVFs of all interventions was 65% at 6 months. Factors with poor patencies of AVFs after PTA procedures were higher serum calcium-phosphate product (p = 0.033), higher URR (p<0.001), lower serum albumin (p<0.001), non-hypertension (p = 0.010) and "non-smoker + ex-smoker group" (p = 0.033). The hypertensive patients and current smokers had lower patency failure after PTAs (p<0.01 and p<0.05, respectively).

CONCLUSIONS

Unfavourable cumulative patency rates are observed in haemodialysis patients with higher URR, higher serum calcium-phosphate product and hypoalbuminaemia (lower serum albumin before the PTA procedure). Hypertension and current smoking were associated with better patency rates of AVF after PTA.

Independent associations of alexithymia and social support with depression in hemodialysis patients

OBJECTIVE

The influences of alexithymia and social support on depression among chronically ill patients were examined prospectively.

METHODS

The study population was 230 outpatients receiving chronic hemodialysis (HD) therapy. The Beck Depression Inventory-II (BDI-II), the 20-item Toronto Alexithymia Scale (TAS-20), and two subscales of the Social Support Questionnaire were given to the subjects. The BDI-II was readministered after a 6-month interval, and subjects who showed deterioration in their depression score above the level predicted from their baseline score were identified. Multivariate logistic analysis adjusted for age, gender, cause of dialysis, and psychosocial variables were performed.

RESULTS

Baseline depression was significantly and independently associated with alexithymia and low satisfaction with available support. Deterioration of depression after 6 months was predicted by alexithymia and poor available support.

CONCLUSIONS

Alexithymia and reduced social support might have independent associations with the presence and the prognosis of depression among HD patients.

Impact of acute and chronic low-dose glucocorticoids on protein metabolism

CONTEXT

High-dose glucocorticoids cause acute protein loss by increasing protein breakdown and oxidation. Whether lower glucocorticoid doses, typical of therapeutic use, induce sustained catabolism has not been studied.

OBJECTIVE

Our objective was to assess the effect of acute and chronic therapeutic glucocorticoid doses on protein metabolism.

DESIGN AND SETTING

We conducted an open longitudinal and a cross-sectional study at a clinical research facility.

PATIENTS AND INTERVENTION

Ten healthy subjects were studied before and after a short course of prednisolone (5 and 10 mg/d sequentially for 7 d each). Twelve subjects with inactive polymyalgia rheumatica receiving chronic (>12 months) prednisone (mean = 5.0 +/- 0.8 mg/d) were compared with 12 age- and gender-matched normal subjects.

MAIN OUTCOME MEASURE

Whole-body protein metabolism was assessed using a 3-h primed constant infusion of 1-[(13)C]leucine, from which rates of leucine appearance (leucine Ra, an index of protein breakdown), leucine oxidation (Lox, index of protein oxidation) and leucine incorporation into protein (LIP, index of protein synthesis) were estimated.

RESULTS

Prednisolone induced an acute significant increase in Lox (P = 0.008) and a fall in LIP (P = 0.08) but did not affect leucine Ra. There was no significant difference between the effects of the 5- and 10-mg prednisolone doses on leucine metabolism. In subjects receiving chronic prednisone therapy, leucine Ra, Lox, and LIP were not significantly different from normal subjects.

CONCLUSION

Glucocorticoids stimulate protein oxidation after acute but not chronic administration. This time-related change suggests that glucocorticoid-induced stimulation of protein oxidation does not persist but that a metabolic adaptation occurs to limit protein loss.

LIGHT--a new member of the TNF superfamily in the plasma, dialysate and urine of uremic patients; the impact of residual diuresis and presence of viral hepatitis

OBJECTIVES

LIGHT is a cytokine involved in atherosclerosis and cardiovascular disease in general population.

DESIGN AND METHODS

We determined the levels of LIGHT in the plasma, dialysate and urine of uremic patients undergoing hemodialysis (HD) and healthy controls.

RESULTS

There were no significant differences in the pre and post-HD plasma levels of LIGHT between HD patients with residual diuresis (HD-RD) and HD anuric group (HD-A) compared to controls. HD-RD patients had the lower LIGHT values in dialysate compared to HD-A patients (p<0.001), and higher urinary LIGHT excretion compared to controls (p<0.05). Moreover, the presence of RD and chronic viral hepatitis were independent factors influencing the levels of this cytokine in dialysate.

CONCLUSIONS

The plasma levels of LIGHT seem to be similar in HD patients and healthy subjects and were not affected by gender, age, the mean period of HD history, disease etiology, type of medication and type of using dialysis membrane.

Serum and dialysate potassium concentrations and survival in hemodialysis patients

BACKGROUND AND OBJECTIVES

Controlling serum potassium is an important goal in maintenance hemodialysis patients. We examined the achievement of potassium balance through hemodialysis treatments and the associated fluctuations in serum potassium.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A 3-yr (July 2001 to June 2004) cohort of 81,013 maintenance hemodialysis patients from all DaVita dialysis clinics across the United States were studied. Nine quarterly-averaged serum potassium groups (< 4.0, > or = 6.3 mEq/L and seven increments in-between) and four dialysate potassium concentration groups were created in each of the 12 calendar quarters. The death risk associated with predialysis potassium level and dialysate potassium concentration was examined using unadjusted, case-mix adjusted, and malnutrition-inflammation-adjusted time-dependent survival models.

RESULTS

Serum potassium correlated with nutritional markers. Serum potassium between 4.6 and 5.3 mEq/L was associated with the greatest survival, whereas potassium < 4.0 or > or = 5.6 mEq/L was associated with increased mortality. The death risk of serum potassium > or = 5.6 mEq/L remained consistent after adjustments. Higher dialysate potassium concentration was associated with increased mortality in hyperkalemic patients with predialysis serum potassium > or = 5.0 mEq/L.

CONCLUSIONS

A predialysis serum potassium of 4.6 to 5.3 mEq/L is associated with the greatest survival in maintenance hemodialysis patients. Hyperkalemic patients who undergo maintenance hemodialysis against lower dialysate bath may have better survival. Limitations of observational studies including confounding by indication should be considered when interpreting these results.

Low serum albumin and high ferritin levels in chronic hemodialysis patients with major depression

We investigated the relationships between serum albumin and ferritin levels in chronic hemodialysis patients with or without major depression. During a 1-year period, a total of 107 chronic hemodialysis patients were recruited. The diagnosis of major depression in patients was made by one psychiatrist. The data showed that patients with major depression (n=15) had significantly lower albumin and higher ferritin levels than patients without major depression (n=92). Chronic hemodialysis patients with major depression might have a more severe inflammation reaction and greater oxidative damage than patients without major depression.

Intradialytic parenteral nutrition does not improve survival in malnourished hemodialysis patients: a 2-year multicenter, prospective, randomized study

Although intradialytic parenteral nutrition (IDPN) is a method used widely to combat protein-calorie malnutrition in hemodialysis patients, its effect on survival has not been thoroughly studied. We conducted a prospective, randomized trial in which 186 malnourished hemodialysis patients received oral nutritional supplements with or without 1 year of IDPN. IDPN did not improve 2-year mortality (primary end point), hospitalization rate, Karnofsky score, body mass index, or laboratory markers of nutritional status. Instead, both groups demonstrated improvement in body mass index and the nutritional parameters serum albumin and prealbumin (P < 0.05). Multivariate analysis showed that an increase in prealbumin of >30 mg/L within 3 months, a marker of nutritional improvement, independently predicted a 54% decrease in 2-year mortality, as well as reduced hospitalizations and improved general well-being as measured by the Karnofsky score. Therefore, although we found no definite advantage of adding IDPN to oral nutritional supplementation, this is the first prospective study demonstrating that an improvement in prealbumin during nutritional therapy is associated with a decrease in morbidity and mortality in malnourished hemodialysis patients.

Which targets in clinical practice guidelines are associated with improved survival in a large dialysis organization?

Professional organizations have developed practice guidelines in the hope of improving clinical outcomes. The National Kidney Foundation's Kidney Disease Outcomes Quality Initiative (KDOQI) has set targets for dialysis dosage (single-pool Kt/V), hematocrit, serum albumin, calcium, phosphorus, parathyroid hormone, and BP for hemodialysis (HD) patients. Several guidelines are largely based on results from observational studies. In contrast to other parameters, BP values within the KDOQI guidelines have been associated with increased mortality. Therefore, it was postulated that having multiple parameters that satisfy the current guidelines, except those for BP, is associated with improved survival among HD patients. A retrospective analysis was conducted of incident HD patients who were treated at facilities operated by Dialysis Clinic Inc., a not-for-profit dialysis provider, between January 1, 1998, and December 31, 2004 (n = 13,792). Cox proportional hazards models were used to assess the association between satisfying guidelines and mortality. Values within guidelines for single-pool Kt/V, hematocrit, serum albumin, calcium, phosphorus, and parathyroid hormone were associated with decreased mortality (P < or = 0.0001). The largest survival benefit was found for serum albumin (hazard ratio [HR] 0.27; 95% confidence interval [CI] 0.24 to 0.31). Satisfying these six guidelines simultaneously was associated with an 89% reduction in mortality (HR 0.11; 95% CI 0.06 to 0.19]). Conversely, BP values satisfying the guideline were associated with increased mortality (HR 1.90; 95% CI 1.73 to 2.10). Because this target was largely extrapolated from the general population, a randomized, controlled trial is needed to identify the optimal BP for HD patients.

Renal replacement therapy in acute renal failure: which index is best for dialysis dose quantification?

BACKGROUND

The "delivered dose" of dialysis may significantly affect the outcome of acute renal failure (ARF) patients requiring dialysis. Our study aimed to elucidate which dose quantification method offers an appropriate parameter to compare different treatments in ARF patients.

METHODS

Six sustained low-efficiency daily dialysis (SLEDD), and 7 continuous venovenous hemofiltration (CVVH) patients with a prescribed Kt/V of 1.0 were studied during a single treatment. CVVH was studied over the first 24 hours after initiation. SLEDD was performed for 6-12 h. Solute clearance (K) was determined by direct dialysate quantification (DDQ). The single-pool Kt/V (spKt/V), equilibrated Kt/V (eqKt/V), equivalent renal urea clearance (EKRc), and solute removal index (SRI) were calculated.

RESULTS

There were no significant differences at enrollment between the SLEDD and the CVVH groups in any patient characteristics except for the serum creatinine levels. The prescribed Kt/V of both groups was similar (SLEDD, 0.9+/-0.22; CVVH, 1.10+/-0.12, p=NS). The EKRc, which is used to verify kinetic equivalence among patients treated with differing renal replacement therapies (RRT), was higher in CVVH (15.7 in SLEDD; 27.4 in CVVH, p<0.0001), despite the fact that there was no difference between the delivered spKt/V for the SLEDD (1.05+/-0.40) and the CVVH (1.10+/-0.11) groups. The values for SRIurea (0.61 in SLEDD; 1.04 in CVVH, p=0.001), SRIcreatinine (0.55 in SLED; 1.02 in CVVH, p<0.0001), and SRIphosphate (1.81 in SLED; 3.60 in CVVH, p=0.03) were higher in CVVH. The EKRc is calculated assuming a steady state, which is an incorrect assumption in ARF patients with hypercatabolism.

CONCLUSION

The SRI calculated using direct dialysate effluent quantification appears to be more reliable as an index of the dialysis dose compared to other methods in ARF patients. However, the use of the dialysate-side SRI is limited by the difficulty of dialysate effluent collection.