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

Determinants of protein turnover in health and disease

Protein synthesis, protein degradation, and amino acid oxidation are tightly regulated to preserve lean body mass in healthy individuals. An adaptative response to a reduction in dietary protein in normal adults is decreased branched-chain amino acid oxidation which increases the availability of amino acids. In nephrosis, reduced branched-chain amino acid oxidation decreases amino acid requirements and helps to compensate for urinary protein loss. Conversely, uremia and other catabolic diseases are associated with muscle wasting resulting from activation of the ubiquitin-proteasome proteolytic pathway and branched-chain ketoacid dehydrogenase, the rate-limiting enzyme for branched-chain amino acid catabolism. By understanding the processes responsible for muscle wasting in catabolic states, therapeutic interventions may be designed to improve protein balance.

Strategies for nutritional intervention in patients with renal failure

This review article discusses the evidence documenting the interrelationship between nutritional status and clinical outcome of the renal patient population. The limitations of accurately assessing the nutritional status of this patient group with commonly used indices are detailed. An overview of the history of nutrition supplementation as an intervention for the malnourished renal patient reveals that the efficacy of both enteral and parenteral methods has not been adequately explored to draw any firm conclusions. Based on available data, recommendations for providing nutrition care for the malnourished patient are provided. Therapeutics that are currently under investigation as future interventions for malnutrition are identified.

Impact of chronic renal failure on nitrogen metabolism

Evidence indicates that both nephrotic and nonnephrotic chronic renal failure (CRF) patients can activate normal compensatory responses when dietary protein intake is restricted and that their protein and energy requirements are similar to normal subjects. When properly implemented, low-protein diets are safe and the benefits include the amelioration of uremic symptoms and some of their metabolic complications and possibly a reduction in the rate of progression of renal failure. To ensure dietary adequacy and compliance, patients should be monitored when treated with low-protein diets. Recent evidence that the protein intake of patients with progressive CRF declines when they consume unrestricted diets should not be considered as an argument against the use of low-protein diets. Rather, it is a persuasive argument in favor of restricting dietary protein intake to minimize the complications of renal failure.

Acute phase proteins and peritoneal dialysate albumin loss are the main determinants of serum albumin in peritoneal dialysis patients

Hypoalbuminemia predicts mortality in dialysis patients. It has been postulated that hypoalbuminemia in the dialysis population is a consequence of poor protein intake resulting from inadequate dialysis. To establish the cause of hypoalbuminemia in a group of 27 patients on peritoneal dialysis (PD), we determined the relationship between serum albumin concentration and a group of parameters including dialysis dose delivered (Kt/V), normalized protein catabolic rate (PCRn), transperitoneal and urinary albumin losses, and the serum concentration of two acute-phase proteins, C-reactive protein (CRP), and serum amyloid A (SAA). Serum albumin concentration could be predicted by a combination of transperitoneal albumin loss and either the serum concentration of CRP or of SAA. There was no relationship between weekly Kt/V or PCRn and serum albumin concentration. CRP and SAA significantly correlated with one another, but neither correlated with transperitoneal albumin losses. Hypoalbuminemia in PD patients is a consequence of transperitoneal albumin losses and of the acute phase response.

National Kidney Foundation report on dialyzer reuse. Task Force on Reuse of Dialyzers, Council on Dialysis, National Kidney Foundation

The Council on Dialysis of the National Kidney Foundation convened an expert panel to evaluate the current practice and literature related to the reuse of hemodialyzers. The panel reviewed and evaluated literature related to reuse since the last report of the National Kidney Foundation recommendations on reuse was published in 1988. The group sought to develop a consensus concerning the effect of reuse of hemodialyzers on mortality; the efficiency of delivered hemodialysis when reused hemodialyzers are used in the clinical setting; the clinical effects of reused dialyzers as compared with dialyzers not reused on intradialytic symptoms; infections in patients using reused dialyzers; and the effect of reused dialyzers on complement activation, cytokine production, and beta2-microglobulin metabolism and clearance. In addition, the panel reviewed the literature on the potential toxicity of germicides used in the processing of dialyzers for reuse as well as recent changes in federally mandated regulations concerning labeling of dialyzers for reuse, the monitoring of the reuse process, and the effectiveness of reused dialyzers to achieve a prescribed delivered clearance as estimated by urea kinetic modeling or by percent urea reduction. The National Kidney Foundation takes no position for or against dialyzer reuse. The principal reason for the practice of reuse is economical. In view of the uncertainties related to the safety and biological impact of reuse procedures, the task force recommends that a full discussion of the issue of reuse and its potential beneficial and detrimental effects be undertaken with each patient. There is no conclusive evidence to substantiate the notion that either morbidity or mortality associated with single use or reuse is different. Microbial contamination of the water used for dialyzer reprocessing increases patient morbidity. The chemical quality of water used for dialyzer reprocessing should, at least, fall within the same standards as those recommended for product water intended for hemodialysis. Dialyzers should not be reprocessed from patients who have tested positive for hepatitis B surface antigen. The effects of reprocessing high-flux dialyzers on beta2-microglobulin clearance are dependent on the reprocessing technique, the number of reuses, and the nature of the dialyzer membrane used. There are insufficient data on the effects of reuse on beta2-microglobulin behavior to make uniform recommendations. Untoward effects of reused dialyzers may still occur in spite of rigorous adherence to the AAMI guidelines. For example, use of the total cell volume method for assessing changes in small molecule clearances will not show the loss of performance attributable to dialysate shunting. For this reason, the measurement of Kt/V for urea as recommended by the AAMI or the determination of the urea reduction ratio (URR) is strongly recommended at least monthly to gauge the adequacy of the dialysis procedure. Given the significant fall in dialyzer efficiency for urea removal that can occur after repeated uses of a dialyzer, dialysis prescriptions in units practicing reuse should be designed to deliver a Kt/V or URR value that exceeds the dose used for patients treated with single-use dialyzers to make allowance for any possible reuse-induced reduction in dialyzer efficiency. Technicians and other personnel responsible for the reprocessing of dialyzers should receive proper training. These health care providers should be certified in reprocessing by an examining body so that professional competency can be assured.

Dialytic nutrition: provision of amino acids in dialysate during hemodialysis

Maintenance hemodialysis (MHD) patients are frequently malnourished, a condition associated with high morbidity and mortality. Amino acid (AA) losses in dialysate may enhance protein malnutrition in patients with low food intake. We studied the possibility of providing AA in dialysate during MHD to either prevent AA losses or as a nutritional supplement. Six clinically stable men were studied during three hemodialysis treatments. The first treatment was performed using the usual dialysate (0XAA). The two other treatments were performed using a dialysate containing an amount of AA equal to normal plasma AA concentrations (1XAA) or to three times the normal plasma AA concentrations (3XAA). During the OXAA treatment, the total AA losses were 10.0 +/- 0.9 (SEM) grams (g) and the total AA concentrations in plasma decreased by 49 +/- 4%. During the 1XAA treatment, the total AA balance was +0.8 +/- 1.8 g and there was no significant change in the postdialysis plasma total AA. With the 3XAA treatment, the patients gained 36.9 +/- 4.1 g of AA during the hemodialysis treatment and the plasma total AA levels increased by 45 +/- 9%. No side effects were observed. These findings indicate that it may be feasible to provide AA supplements to MHD patients by adding AA to hemodialysate.

Elevated fasting total plasma homocysteine levels and cardiovascular disease outcomes in maintenance dialysis patients. A prospective study

There is an excess prevalence of hyperhomocysteinemia in dialysis-dependent end-stage renal disease (ESRD) patients. Cross-sectional studies of the relationship between elevated total homocysteine (tHcy) levels and prevalent cardiovascular disease (CVD) in this patient population suffer from severe methodologic limitations. No prospective investigations examining the association between tHcy levels and the subsequent development of arteriosclerotic CVD outcomes among maintenance dialysis patients have been reported. To assess whether elevated plasma tHcy is an independent risk factor for incident CVD in dialysis-dependent ESRD patients, we studied 73 maintenance peritoneal dialysis or hemodialysis patients who received a baseline examination between March and December 1994, with follow-up through April 1, 1996. We determined the incidence of nonfatal and fatal CVD events, which included all validated coronary heart disease, cerebrovascular disease, and abdominal aortic/lower-extremity arterial disease outcomes. After a median follow-up of 17.0 months, 16 individuals experienced at least one arteriosclerotic CVD event. Cox proportional-hazards regression analyses, unadjusted and individually adjusted for creatinine, albumin, and total cholesterol levels, total/HDL cholesterol ratio, dialysis adequacy/residual renal function, baseline CVD, and the established CVD risk factors (ie, age, sex, smoking, hypertension, diabetes/glucose intolerance, and dyslipidemia) revealed that tHcy levels in the upper quartile (> or = 27.0 mumol/L) versus the lower three quartiles (< 27.0 mumol/L) were associated with relative risk estimates (hazards ratios, with 95% confidence intervals for the occurrence of (pooled) nonfatal and fatal CVD ranging from 3.0 to 4.4; 95% confidence intervals (1.1-8.1) to (1.6-12.2). We conclude that the markedly elevated fasting tHcy levels found in dialysis-dependent ESRD patients may contribute independently to their excess incidence of fatal and nonfatal CVD outcomes.

Some of the small print on managed care proposals for end-stage renal disease

In this article we discuss selected issues related to Medicare's end-stage renal disease (ESRD) managed care demonstration project and Congressional proposals to remove the barrier to ESRD patients enrolling in Medicare managed care plans. We discuss financial incentives to keep patients healthy; beneficiary obligations under fee-for-service and managed care; risk selection by beneficiaries among plans; and the baseline determination of a capitation rate. The ESRD demonstration offers the opportunity to evaluate the consequences of making Medicare managed care options available to a high cost and clinically vulnerable population. Careful evaluation is necessary to ensure that ESRD managed care options are structured to be beneficial to taxpayers, caregivers, and, most importantly, the beneficiaries choosing these options. Certainly, the potential exists for managed care to benefit patients by changing the fractured system in which each provider only has an incentive to worry about its own costs. However, the possible unintended consequences highlighted in this article strongly suggest that the evaluation of the demonstration project be undertaken before managed care options are made widely available outside the demonstration sites. Problems of a more technical nature, such as how to best use available Health Care Financing Administration data in the rate-setting process, are likely to be overcome, but the time and effort necessary to resolve them should not be underestimated.

Patient assessments of adequacy of dialysis and protein nutrition

Nephrologists closely monitor biochemical measurements of adequacy of dialysis and protein nutrition, but little is known about how patients assess adequacy. We sought (1) to determine how hemodialysis patients assess adequacy and (2) to compare patient assessments with objective measures of adequacy. We performed a cross-sectional interview study of 145 patients from two chronic hemodialysis units. Using a structured questionnaire, we asked subjects to assess the amount of dialysis and protein nutrition they were getting. Objective measures of amount of dialysis (Kt/V) and protein nutrition (albumin) were obtained from chart abstraction. We found that only 5% of all subjects thought they were getting less dialysis than they needed, yet 41% were actually receiving inadequate dialysis (Kt/V <1.2). Even among the 60 subjects with Kt/V less than 1.2, only 5% thought they were getting less dialysis than they needed. Similarly, 21% of all subjects thought they were getting less protein nutrition than they needed, yet 28% had inadequate protein nutrition levels (albumin <3.5 g/L). Even among the 41 subjects with albumin less than 3.5 g/L, only 20% thought they were getting less protein nutrition than they needed. In conclusion, patient assessments of adequacy differ greatly from the objective measures that nephrologists use to assess adequacy. Most patients with Kt/V less than 1.2 or albumin less than 3.5 g/L think they are getting adequate dialysis and protein nutrition. Understanding how patients assess adequacy may be an important step in developing interventions to improve the adequacy of dialysis and protein nutrition.

Effect of dietary protein restriction on nutritional status in the Modification of Diet in Renal Disease Study

The safety of dietary protein and phosphorous restriction was evaluated in the Modification of Diet in Renal Disease (MDRD) Study. In Study A, 585 patients with a glomerular filtration rate (GFR) of 25 to 55 ml/min/1.73 m2 were randomly assigned to a usual-protein diet (1.3 g/kg/day) or a low-protein diet (0.58 g/kg/day). In Study B, 255 patients with a GFR of 13 to 24 ml/min/1.73 m2 were randomly assigned to the low-protein diet or a very-low-protein diet (0.28 g/kg/day), supplemented with a ketoacid-amino acid mixture (0.28 g/kg/day). The low-protein and very-low-protein diets were also low in phosphorus. Mean duration of follow-up was 2.2 years in both studies. Protein and energy intakes were lower in the low-protein and very-low-protein diet groups than in the usual-protein group. Two patients in Study B reached a "stop point" for malnutrition. There was no difference between randomized groups in the rates of death, first hospitalizations, or other "stop points" in either study. Mean values for various indices of nutritional status remained within the normal range during follow-up in each diet group. However, there were small but significant changes from baseline in some nutritional indices, and differences between the randomized groups in some of these changes. In the low-protein and very-low-protein diet groups, serum albumin rose, while serum transferrin, body wt, percent body fat, arm muscle area and urine creatinine excretion declined. Combining patients in both diet groups in each study, a lower achieved protein intake (from food and supplement) was not correlated with a higher rate of death, hospitalization or stop points, or with a progressive decline in any of the indices of nutritional status after controlling for baseline nutritional status and follow-up energy intake. These analyses suggest that the low-protein and very-low-protein diets used in the MDRD Study are safe for periods of two to three years. Nonetheless, both protein and energy intake declined and there were small but significant declines in various indices of nutritional status. These declines are of concern because of the adverse effect of protein calorie malnutrition in patients with end-stage renal disease. Physicians who prescribe low-protein diets must carefully monitor patients' protein and energy intake and nutritional status.

Methodological limitations of the ESRD Core Indicators Project: an ESRD network's experience with implementing an ESRD quality survey. Medical Review Board of the ESRD Network of New England

ESRD Network Number 1, composed of Maine, New Hampshire, Vermont, Massachusetts, Connecticut, and Rhode Island, developed a Network Core Indicator Pilot Project using the dialysis units represented on the Medical Review Board. Network 1's Core Indicator Pilot Project aimed to (1) estimate the proportion of end-stage renal disease (ESRD) patients in Network 1 receiving hemodialysis treatments associated with a urea reduction ratio less than 60% to 65%, (2) elucidate the patient characteristics associated with a hemodialysis dose less than 65%, (3) define the processes in the delivery of hemodialysis that limit the provision of an adequate dialysis dose, and (4) initiate the routine collection of measures of dialysis dose, the analysis of those data, and feedback to the participating dialysis units. In the course of the Core Indicator Pilot Project, we observed little uniformity in the sampling method for the postdialysis blood urea nitrogen sample. Thirty-three percent of the hemodialysis units reported that this critical blood sample was drawn immediately before the dialysis treatment was terminated; 25% were obtained immediately at the end of the dialysis treatment and 42% drew the sample > or = 5 minutes after all blood was reinfused to the patient. Especially in the presence of unappreciated blood recirculation in the angioaccess or postdialysis urea rebound, the lack of standardization in obtaining this critical blood sample to support the urea reduction ratio calculation greatly compromises any comparisons of performance across dialysis facilities and may jeopardize patient care. Future ESRD quality improvement efforts must focus not only on the results of the outcome measure but also on the process by which the measure is achieved. These fundamental principles of quality assessment should be considered by policy specialists, payers, providers, and developers of clinical practice guidelines.

Differences in quality of life among patients receiving dialysis replacement therapy at seven medical centers

The purpose of this study is to investigate the variations in quality of life (QOL) among patients with end-stage renal disease (ESRD) who are receiving replacement therapy in several dialysis centers. This observational study includes interviews with nurses and data extraction from medical charts for all 680 adults who had been on dialysis therapy for more than 4 weeks in seven dialysis centers. By using multivariate analysis, we generated a model to explain the variance in QOL as measured by the QL index score (developed by Spitzer et al., J Chronic Dis 1981; 34:585-597) among patients pooled from all centers. The expected mean QL index score and 95% confidence interval were computed for each dialysis center. Centers with observed mean QL index scores outside of the expected confidence range were marked as possible outliers. We found the following patient attributes to be independently associated with QOL: age, education, occupation, and certain comorbidities (e.g., diabetes, stroke). After adjustment for case mix, we could identify four outlier centers. After further adjustment for albumin in serum, a possible process indicator, two centers were no longer considered as outliers. These findings indicate that the variance in QOL of ESRD patients at different centers is not entirely explained by known case-mix factors. Further research should explore whether such variations are related to dissimilarity in the process of care at different centers.

Hypoalbuminemia causes high blood viscosity by increasing red cell lysophosphatidylcholine

Albumin deficiency is accompanied by a reduction in red cell deformability and blood hyperviscosity. Albumin deficiency increases plasma fibrinogen and triglyceride levels and may alter red cell membrane lipid composition. These options, which could all contribute to reduced red cell deformability (RCD) and hyperviscosity, were studied in the Nagase analbuminemic rat (NAR), a mutant Sprague Dawley rat (CON), characterized by normal total protein levels, with an absolute deficiency of albumin, but elevated levels of non-albumin proteins and hyperlipidemia. Plasma protein-binding of the polar phopholipid lysophosphatidylcholine (LPC) was markedly decreased. LPC comprised only 26 +/- 1% of total plasma phospholipids as compared to 42 +/- 2% in CON. NAR red cells in CON plasma had a viscosity that was similar to CON red cells in CON plasma. Conversely, CON red cells in NAR plasma show an increased viscosity as compared to CON red cells in CON plasma. The maximum deformation index of both NAR and CON red cells was markedly decreased in NAR plasma as compared to either NAR or CON cells in CON plasma (0.04 +/- 0.03 and 0.02 +/- 0.02 vs. 0.22 +/- 0.06 and 0.15 +/- 0.04, respectively; P < 0.05). Thus, plasma composition causes hyperviscosity and reduced RCD in NAR. Fibrinogen is not responsible since red cells in serum and red cells in plasma had a similar viscosity and differences in viscosity and RCD between NAR and CON were maintained. Plasma triglycerides are also not responsible since the viscosity of red cells in serum with a 50% reduction in triglycerides was not reduced. LPC levels in red cells were increased in NAR (8.7 +/- 0.2 vs. 5.5 +/- 0.3% of total phospholipids; P < 0.01). Adding albumin to NAR blood dose-dependently decreased whole blood viscosity, despite marked increases in plasma viscosity, and increased RCD of NAR cells (from 0.04 +/- 0.03 to 0.21 +/- 0.01; P < 0.05). There was also some effect on CON RCD of similar albumin addition to CON blood (from 0.15 +/- 0.04 to 0.29 +/- 0.03; P < 0.05). Adding albumin to NAR blood reduced red cell LPC content and increased plasma LPC content in a dose-dependent fashion, whereas there were only slight effects of adding albumin to CON blood. There was a reciprocal relation between red cell LPC and the other polar phospholipids in the red cell membrane, probably indicating exchange. The maximum deformability index of either NAR or CON cells was not affected much by adding LPC to CON plasma (NAR, from 0.22 +/- 0.06 to 0.18 +/- 0.10; CON, from 0.15 +/- 0.04 to 0.12 +/- 0.05; NS), whereas adding LPC to NAR plasma caused the red cells to become rigid. Adding LPC to CON red cells in NAR plasma caused a much stronger increase in relative LPC content (from 6.6 +/- 0.7 to 10.9 +/- 0.9%; P < 0.05) than adding LPC to CON red cells in CON plasma (from 5.6 +/- 0.4 to 6.4 +/- 0.8%; NS). Thus, in the absence of albumin, LPC in red blood cells is increased. As a consequence of the latter, RCD is decreased and whole blood viscosity increased. Alterations in red cell phospholipids are far more important than increases in plasma fibrinogen or triglycerides in determining hyperviscosity of blood and reduced RCD in NAR.

Hemodialysis versus peritoneal dialysis: a comparison of adjusted mortality rates

Although kidney transplantation is the preferred treatment method for patients with ESRD, most patients are placed on dialysis either while awaiting transplantation or as their only therapy. The question of which dialytic method provides the best patient survival remains unresolved. Survival analyses comparing hemodialysis and continuous ambulatory peritoneal dialysis/continuous cyclic peritoneal dialysis (CAPD/CCPD), a newer and less costly dialytic modality, have yielded conflicting results. Using data obtained from the Canadian Organ Replacement Register, we compared mortality rates between hemodialysis and CAPD/CCPD among 11,970 ESRD patients who initiated treatment between 1990 and 1994 and were followed-up for a maximum of 5 years. Factors controlled for include age, primary renal diagnosis, center size, and predialysis comorbid conditions. The mortality rate ratio (RR) for CAPD/CCPD relative to hemodialysis, as estimated by Poisson regression, was 0.73 (95% confidence interval: 0.68 to 0.78). No such relationship was found when an intent-to-treat Cox regression model was fit. Decreased covariable-adjusted mortality for CAPD/CCPD held within all subgroups defined by age and diabetes status, although the RRs increased with age and diabetes prevalence. The increased mortality on hemodialysis compared with CAPD/CCPD was concentrated in the first 2 years of follow-up. Although continuous peritoneal dialysis was associated with significantly lower mortality rates relative to hemodialysis after adjusting for known prognostic factors, the potential impact of unmeasured patient characteristics must be considered. Notwithstanding, we present evidence that CAPD/CCPD, a newer and less costly method of renal replacement therapy, is not associated with increased mortality rates relative to hemodialysis.

Cardiac disease in chronic uremia: epidemiology

Cardiac abnormalities develop during chronic renal failure. The prevalence of ischemic heart disease, cardiac failure, and left ventricular disorders is high among patients initiating end-stage renal disease (ESRD) therapy, and appears to be getting higher. Age, gender, race, diabetes, and possibly geographic location are predictive of the presence of several cardiac conditions. Cardiac morbidity after the initiation of ESRD therapy is high, and cardiac causes are the most common reported cause of death. Cardiac abnormalities present on starting dialysis contribute to this morbidity and mortality. In epidemiological studies, higher cardiac death rates have also been associated with dialysis rather than transplantation as mode of ESRD therapy, peritoneal rather than hemodialysis, lower dose of dialysis, and unmodified cellulose rather than modified cellulose/synthetic hemodialysis membranes.

Clinical outcome relative to the dose of dialysis is not what you think: the fallacy of the mean

Several recent retrospective studies of mortality relative to the dose of dialysis have been widely interpreted to indicate that adequate thrice-weekly hemodialysis requires a single pool Kt/V (spKt/V) of at least 1.4 to 1.6 and higher. In these studies, mortality rate has been correlated to the mean delivered spKt/V, (spKt/Vd)m, with coefficient of variation (CV) on the means ranging up to 45%. To evaluate these reported relationships, two large databases were analyzed using population constants to transform urea reduction ratio and spKt/Vd to equilibrated Kt/Vd (eKt/Vd), which expresses dose corrected for treatment time. The eKt/V dose (D) values were correlated to the reported relative risks (RR) of mortality to derive a RR/D function. The RR/D function, derived from these data with stepwise linear regression analysis, is nonlinear, with a steep linear increase in RR for eKt/Vd less than 1.05 and constant RR for eKt/Vd > or = 1.05. This RR/D function is mathematically expressed as RR = 1.96 - 1.03(eKt/Vd) (equation 1) when 0.50 < or = eKt/Vd < or = 1.05, and RR = 0.88 (equation 2) when eKt/V > or = 1.05. We show that regression of RR on (eKt/Vd)m with large CV results in overestimation of RR relative to eKt/Vd for individual patients because of extrapolation of the linear relationship beyond the threshold where the slope becomes zero (see equation 2 above). It is concluded that (1) current clinical data indicate that adequate dialysis is provided with eKt/Vd of 1.0 to 1.1 on a thrice-weekly schedule, (2) it is essential to assure that all patients achieve this level of therapy, which is best accomplished using urea kinetic modeling for both prescription and measurement of delivered eKt/Vd, and (3) the current HEMO study is well designed to determine whether higher levels of eKt/Vd will further improve clinical outcome.

Cardiac disease in chronic uremia: clinical outcome and risk factors

Cardiac disease is common and is the major killer in end-stage renal disease (ESRD). Cardiac failure is a highly malignant condition in ESRD patients. Cardiac failure mediates most of the adverse prognostic impact of ischemic heart disease. Left ventricular (LV) abnormalities are already present at initiation of dialysis therapy in approximately 80% of patients. These abnormalities (ie, systolic dysfunction in approximately 15%, LV dilatation with preserved systolic function in 30%, concentric LV hypertrophy [LVH] in 40%) independently predict ischemic heart disease and cardiac failure, and are the largest baseline predictor of mortality after 2 years on dialysis therapy. The associations between classical risk factors (eg, hyperlipidemia, smoking, hypertension) and cardiac outcomes in ESRD are inconsistent. "Uremic" risk factors represent a nascent, but potentially important field. In our prospective 10-year study of 433 patients starting renal replacement therapy, we identified the following as major independent risk factors for cardiac disease: (1) hypertension (concentric LVH, LV dilatation, ischemic heart disease, cardiac failure, inverse relationship with mortality); (2) anemia (LV dilatation, cardiac failure, death); and (3) hypoalbuminemia (ischemic heart disease, cardiac failure, death). Transplantation dramatically improved LV abnormalities, suggesting that a uremic environment is cardiotoxic. Multiple risk factors act in concert to produce cardiac disease in ESRD; many of these are avoidable, suggesting that the enormous burden of disease can be reduced considerably.

Association of serum albumin and mortality risk

Reduced levels of serum albumin concentration, a routine blood test, within the "normal" range have been reported to be associated with mortality risk. The literature is reviewed, with a focus on cohort studies meeting specified criteria, and findings are summarized. In studies of many populations, comprising healthy subjects and patients with acute or chronic illness, serum albumin concentration is inversely related to mortality risk in a graded manner over its entire range; the estimated increase in the odds of death ranges from 24% to 56% for each 2.5 g/l decrement in serum albumin concentration. The association predicts overall and cause-specific mortality including cardiovascular mortality. It is likely that albumin concentration is a highly sensitive indicator of preclinical disease and disease severity. A direct protective effect of the albumin molecule is suggested by the persistence of the association after adjustment for other known risk factors and preexisting illness, and after exclusion of early mortality. Although biologically plausible, there is no direct evidence for this hypothesis. Serum albumin concentration is an independent predictor of mortality risk and could be useful in the quantification of risk in a broad range of clinical and research settings.

Protein intake and the nutritional status in patients with pre-dialysis chronic renal failure on unrestricted diet

OBJECTIVES

Malnutrition is known to be highly associated with morbidity and mortality in dialysis patients. Malnutrition may begin to develop in patients with chronic renal failure(CRF) before they need dialysis. In this study, the nutritional status of patients with moderate to severe CRF on unrestricted diet was evaluated.

METHODS

We measured dietary protein intake (DPI, g/kg/day) in 64 patients with CRF and 42 normal controls(N). Nutritional indices such as serum albumin(SA, g/dl), transferrin(TF, mg/dl), prealbumin(PA, mg/dl) and insulin-like growth factor-1(IGF-1, ng/ml) were measured to evaluate the visceral proteins, and creatinine-height index(C-H, g/d/m) to evaluate the somatic proteins.

RESULTS

Mean DPI was 0.80 +/- 0.27(S.D) in CRF and 1.07 +/- 0.30 in N(p < 0.0001). DPI was lower than 0.6 in 15 CRF patients(23%). Serum albumin, transferrin and C-H were significantly lower in CRF patients than in N(p < 0.01). In patients with CRF, nutritional indices were significantly worse with lower DPI(< 0.6 g/kg/d, n = 15) than higher DPI(> 0.6 g/kg/d, n = 49)(SA 2.9 +/- 0.7 vs. 3.6 +/- 0.8, p < 0.005; TF 147 (134-179) vs. 220(182-264), p < 0.0005; PA 24 +/- 8 vs. 32 +/- 9, p < 0.001; IGF-1 123 (66-261) vs. 226(140-344), p < 0.05; C-H 0.52 +/- 0.15 vs. 0.87 +/- 0.23, p < 0.0001). CRF patients with nephrotic range proteinuria (> 3.5 g/d, n = 19) had lower SA (2.8 +/- 0.6 vs. 3.8 +/- 0.8, p < 0.0001) and PA(27 +/- 9 vs. 32 +/- 9, p < 0.05). CRF patients with diabetes mellitus (n = 20) showed worse nutrition than non-diabetic patients(SA 2.8 +/- 0.6 g/dl vs. 3.8 +/- 0.8 g/dl, p < 0.0001; TF 176 mg/dl(148-214) vs. 220 mg/dl(175-266), p < 0.05; PA 24 +/- 10 mg/dl vs. 33 +/- 8 mg/dl, p < 0.0005; IGF-1 138 ng/ml(69-269) vs 231 ng/ml(140-364), p < 0.05; C-H 0.66 +/- 0.23 vs. 0.85 +/- 0.5, p < 0.005).

CONCLUSION

A significant protein malnutrition prevails in patients with pre-dialysis CRF on unrestricted diet, especially with low protein intake. The effort to detect and correct malnutrition should be made in patients with CRF even before initiation of maintenance dialysis.

Use of the medical differential diagnosis to achieve optimal end-stage renal disease outcomes

Compared with the general population, end-stage renal disease (ESRD) patients continue to have a higher than expected morbidity and mortality. Hypoalbuminemia, anemia, hypertension, and inadequate dialysis are all thought to contribute to the high morbidity and mortality among ESRD patients. Anemia algorithms should help to standardize the approach to anemia and the use of recombinant human erythropoietin (rHuEPO), but clinicians still must review each patient individually, searching for and treating the multitude of interrelated factors that affect rHuEPO responsiveness. Hypoalbuminemia is a very strong predictor of increased morbidity and mortality in dialysis and nondialysis patients. The causes of hypoalbuminemia are multifactorial, and diagnosis of the cause of hypoalbuminemia is usually elusive. The basis of the poorer survival in US dialysis patients remains controversial, but inadequate dialysis has been implicated. To assure adequate dialysis, the dialysis prescription must be individualized for each patient, and delivered dialysis must be routinely monitored. Hypertension is associated with left ventricular hypertrophy, which is also an important determinant of survival in ESRD patients. Hypertension should be treated in ESRD patients in conjunction with other interventions that are known to reverse left ventricular hypertrophy. Special efforts must be made in the medical management of hypoalbuminemia, anemia, hypertension, and dialysis treatment adequacy to improve survival in patients with ESRD.

Use of dietetic-specific nutritional diagnostic codes in clinical reasoning relevant to the nutritional management of core clinical outcome indicators in hemodialysis patients

The Health Care Financing Agency (HCFA) has recommended conscientious monitoring of four core outcome indicators (anemia, albumin, treatment adequacy, and hypertension) by the end stage renal disease (ESRD) health care team. Dietetic-specific nutritional diagnostic categories (D-S NDCs) can be a powerful tool in guiding renal nutrition specialists through the clinical reasoning required to diagnose and clinically correct nutrition-related problems in hemodialysis (HD) patients. The purpose of this article is to portray one clinician's dual use of D-S NDCs to identify the nutritional problem responsible for poor performance and determine nutritionally treatable causes. Although four indicator-specific sets of D-S NDCs commonly used in the nutritional assessment of anemia, albumin, treatment adequacy and hypertension were identified and referenced, seven codes were consistently repeated. These D-S NDCs were (1) altered nutritional biochemistry integrity; (2) absence of/limited nutritional service; (3) deficit in nutrition knowledge; (4) imbalance of nutrient/fluid; (5) nutrition misinformation; (6) toxicity of nutrient/nutrient end-product; and (7) possibility of developing a specific disease. Thus, in ESRD, use of D-S NDCs shows the implicit role of the registered dietitian in disease prevention, management of altered nutrient disposition, and patient education.

Serum and urine albumin: a progress report on their measurement and clinical significance

For about 25 years, bromcresol green and bromcresol purple have been the basis for most of the measurements of serum albumin in the US and perhaps in the world. The longevity of the methods is due to their being simple, sensitive, specific, inexpensive and relatively free from interferences. The lack of change in the serum albumin methodology is balanced by two important developments. First, the recognition of the importance of serum albumin in the maintenance of good health, and the association of decreased concentrations with increased risk of morbidity and mortality. Second, the association of albuminuria with diabetic nephropathy, which without medical intervention could lead to end-stage renal disease. The development of accurate and precise methods for urinary albumin has provided a tool to physicians to extend the length and improve the quality of life of many diabetic individuals.

[Malnutrition in hemodialysis patients. Self-assessment, medical evaluation and "verifiable" parameters]

BACKGROUND

Malnutrition in hemodialysis patient is associated with increased mortality and morbidity. Inventions to treat malnutrition are often ineffective. Underestimation by the patients of the importance of dietary interventions might negatively influence any therapeutic outcome. We examined the correlation between nutritional assessment by the patient himself and clinical assessment by the physician.

PATIENTS AND METHODS

Subjective global assessment (SGA) was performed in 68 chronic hemodialysis patients Serum concentrations of albumin, prealbumin, transferrin and cholesterin were measured Protein intake was estimated by protein catabolic rate (nPCR). In form of a questionnaire patients were asked to assess then own nutrition.

RESULTS

According to SGA-criteria, moderate to severe malnutrition was found in 34% of our patients. In this unauthorized group serum albumin was < 4.0 g/dl in 45% of patients and correlated best with clinical nutritional assessment. Specificity was lower for prealbumin, transferrin, cholesterin, and nPCR. The questionnaire was completed by 85% of patients. Self-assessment of their own nutrition was discrepant to clinical assessment in 84% of malnourished patients. A similar percentage (79%) of malnourished patients considered their own body weight to be adequate, while only 21% indicated desire to gain weight.

CONCLUSIONS

Our data indicate that a significant percentage of malnourished hemodialysis patients shows a tendency to overestimate their own nutrition. This may negatively influence patient compliance and should be considered in dietary counseling of malnourished chronic hemodialysis patients.

African-Americans on maintenance dialysis: a review of racial differences in incidence, treatment, and survival

African-Americans are the fasting growing racial minority with end stage renal disease (ESRD) in the United States. Currently, African-Americans comprise approximately 31% of the ESRD population. African-Americans are almost a decade younger than their white (referring to non-Hispanic white) counterparts with ESRD with a mean age of 58 years old. Although African-Americans systematically receive less dialysis than whites (Kt/V of 1.05 versus 1.18, respectively), their survival is higher. The 2-year survival probability of African-Americans is 66.2% in comparison with 59.8% for whites. This improved survival with ESRD is accompanied by an improved quality of life for African-Americans. Their enhanced quality of life is reflected by a greatly decreased frequency of withdrawing from dialysis treatments. In this article, we will examine the reasons why African-Americans have an excessive incidence of selective diseases that culminate in ESRD. We will explore the factors that influence the difference in dialysis modality selection between African-Americans and whites. Lastly, we will pose and judge several hypotheses that may account for the improved survival enjoyed by African-Americans with ESRD. We contend that research to clarify the basis for these differences between African-Americans and whites with ESRD will improve outcomes for both populations and is fiscally sound health policy.

Predictive value of nutritional markers (albumin, creatinine, cholesterol, and hematocrit) for patients on dialysis for up to 30 years

Mortality among end-stage renal disease patients in the United States remains unacceptably high despite progress in the management of renal replacement therapy. Consequently, there are few reports of long-term survivors on dialysis. We have analyzed characteristics of long-term (10 to 15 years, N = 40) and very long-term (15 to 30 years, N = 18) survivors on hemodialysis and long-term survivors (more than 10 years, N = 28) on peritoneal dialysis and compared them with "average survivors" (< 5 years, N = 65 for hemodialysis and N = 101 for peritoneal dialysis). Among hemodialysis patients, long- and very long-term survival was associated with younger age, nondiabetic status, black race, and male gender (P < 0.05 for all variables). Enrollment creatinine was higher among long- and very long-term survivors, whereas albumin and hematocrit increased significantly during the period of observation among long- and very long-term survivors compared with average survivors. Enrollment age, nondiabetic status, and albumin level predicted prolonged survival even after adjustments for confounding variables. Among peritoneal dialysis patients, younger age and nondiabetic status predicted prolonged survival. Black race was associated with improved survival, but the association was not statistically significant. Enrollment levels of albumin and creatinine were significantly higher among long-term survivors and the cholesterol increased during the period of observation in long-term survivors. Thus, demographic and biochemical indices reflecting nutritional status can predict prolonged survival in hemodialysis and peritoneal dialysis. Patient survival for periods of up to 30 years is possible on renal replacement therapy. Analyses of these outlier patients may offer clues to prolonged survival.

An observational study of cardiovascular characteristics of long-term end-stage renal disease survivors

Long-term survival with end-stage renal disease (ESRD) on dialysis is uncommon, mainly because of the high mortality associated with cardiovascular disease. To define the clinical characteristics of long-term ESRD survivors, especially their cardiovascular risk profile, patients were identified with > or = 15 years of ESRD having at least 10 years on dialysis. Seventeen patients were identified with a duration of ESRD of 21.0 +/- 4.3 years (mean +/- SD). The age of the patients at the initiation of dialysis was 38.4 +/- 14.5 years. Eighty-eight percent of the survivors were white, and 12% were African-American. The primary causes of ESRD were glomerulonephritis, 65%; polycystic kidney disease, 18%; tubulointerstitial/obstructive disorders, 12%; and hypertension, 6%. At the initiation of dialysis, these long-term survivors presented with a low prevalence of cardiovascular risk factors (hypertension, 53%; diabetes mellitus, 0%; active smoking, 11.8%; family history, 25%) and cardiovascular disease (coronary heart disease, 5.9%; congestive heart failure, 5.9%; arrhythmias, 0%; peripheral vascular disease, 0%; and cerebrovascular disease, 5.9%). In addition, only 6.6% of the long-term ESRD survivors presented with systolic blood pressures < 110 mm Hg, a level suggestive of systolic dysfunction. After > or = 15 years of dialysis, these long-term survivors remained with a low prevalence of cardiovascular risk factors and cardiovascular disease. These results suggest that the low cardiovascular risk profile and morbidity experienced by these patients may contribute to their prolonged survival on dialysis.

The magnitude of metabolic acidosis is dependent on differences in bicarbonate assays

Metabolic acidosis has been recently recognized as an important comorbid event in the high mortality rates seen in patients with end-stage renal disease. The recognition of hypobicarbonatemia is dependent on a reliable assay for total carbon dioxide (TCO2). It is common practice for dialysis facilities to send blood samples for testing to remote laboratories, which may assay bicarbonate differently than the local hospital. We noted that serum bicarbonate concentrations from blood samples sent to our reference laboratory were significantly lower (4 mEq/L) compared with blood samples sent to our local laboratory. Blood samples were assayed for TCO2 using an enzymatic technique (in the reference laboratory) and direct measurement using an electrode (in the local laboratory). The blood test results for TCO2 sent to the reference laboratory (18.7 +/- 0.8 mEq/L) were significantly lower than samples assayed in our local laboratory (22.2 +/- 0.7 mEq/L). In conclusion, recognition of the differences in assays used in the laboratory for routine bicarbonate measurements is important in defining the magnitude of metabolic acidosis and in helping to dictate appropriate therapy.

Use of vancomycin in high-flux hemodialysis: experience with 130 courses of therapy

Vancomycin is often administered to hemodialysis patients at long dosage intervals because its removal by hemodialysis is considered to be negligible. We and others, however, have demonstrated significant removal of vancomycin by high-flux hemodialysis. This report describes our experience with 89 courses of vancomycin using a revised regimen with a loading dose followed by 500 mg doses after each dialysis treatment, and compares results with 41 courses using single weekly dosing. All patients were dialyzed with high-flux membranes using volumetric ultrafiltration and bicarbonate dialysate. Serum vancomycin levels were obtained two hours after completion of infusion (peak) and immediately prior to dialysis (trough) and were measured by Abbot TDx fluorescence polarization immunoassay. Duration of multiple-dose therapy was 11 +/- 8 days, with mean total dose 3.6 +/- 1.8 g. Initial doses of 20 mg/kg rapidly and reliably established therapeutic pre-dialysis serum levels (10 to 25 micrograms/ml). In patients treated with multiple dosing 431 pre-dialysis levels were obtained. The mean level was 15.9 +/- 5.7 micrograms/ml; 55 levels (13%) were less than 10 micrograms/ml and 22 (5%) were above 25 micrograms/ml. In patients treated once weekly, 77% of levels were below 10 micrograms/ml by five days after administration, and 84% at one week. No patient developed demonstrable ototoxicity. Twenty-five patients were treated for > or = two weeks, five for > or = four weeks, and two for > five weeks, with no evidence of toxic accumulation. Mean peak level was 20.1 +/- 4.6 micrograms/ml, with a mean difference from preceding pre-dialysis level of 7.2 +/- 2.2 micrograms/ml. We conclude that in high-flux hemodialysis, a 20 mg/kg loading dose of vancomycin followed by 500 mg doses after each dialysis treatment achieves predictable, adequate and safe therapeutic levels, does not lead to unacceptably high peaks, and does not accumulate during long treatment courses. By contrast, once-weekly vancomycin dosing resulted in subtherapeutic serum levels after five to seven days, and should be abandoned in the high-flux setting.

Relationship of dose of hemodialysis and cause-specific mortality

A number of studies have found a relationship of lower all-cause mortality risk for ESRD patients treated with increasing dose of dialysis. The objective of this study was to determine the relationship of delivered dose of dialysis with cause-specific mortality. Data from the USRDS Case Mix Adequacy Study, which includes a national random sample of hemodialysis patients, were utilized. To minimize the contribution of unmeasured residual renal function, the sample used in this analysis (N = 2479) included only patients on dialysis for one year or more. Cox proportional hazards models, stratified for diabetes, were used to analyze the effect of delivered dose of dialysis (measured and reported by both Kt/V and URR) on major causes of death and withdrawal from dialysis, adjusting for other covariates including demographics, comorbid diseases present at start of study, functional status, laboratory values and other dialysis parameters. Patient follow-up for mortality was censored at the earliest of time of transplantation, 60 days after a switch to peritoneal dialysis or at the time of data abstraction. For each 0.1 higher Kt/V, the adjusted relative risk of death due to coronary artery disease was 9% lower (RR = 0.91, P < 0.05), due to other cardiac causes was 12% lower (RR = 0.88, P < 0.01), due to cerebrovascular disease (CVD) was 14% lower (RR = 0.86, P < 0.05), due to infection was 9% lower (RR = 0.91, P = 0.05), and due to other known causes was 6% lower (RR = 0.94, P < 0.05). There was no statistically significant relationship of Kt/V and risk of death among patients who died of malignancy (RR = 0.84, P = 0.10) or among patients whose death cause was missing (RR = 0.95, P = 0.41). The risk of withdrawal from dialysis prior to death due to any cause was 9% lower (RR = 0.91, P < 0.05) for each 0.1 higher Kt/V. The relationships of delivered dose of dialysis, as measured by URR, and cause-specific mortality were essentially similar in relative magnitude and statistical significance as the relationships observed using Kt/V as the measurement of dialysis dose, with the exception that the relationship was less significant for cerebrovascular disease and withdrawal from dialysis. The relationship of dialysis dose with risk of death due to each cause of death category except other cardiac causes and "other" causes appeared to be of greater magnitude and of greater statistical significance among diabetics than non-diabetics. These results indicate that low dose of dialysis is not associated with mortality due to just one isolated cause of death, but rather is due to a number of the major causes of death in this population. This study is consistent with hypotheses that low doses of dialysis may promote atherogenesis, infection, malnutrition and failure to thrive through a variety of pathophysiologic mechanisms. Further study is necessary to confirm these results and to test hypotheses that are developed.

The dose of hemodialysis and patient mortality

The relationship between the delivered dose of hemodialysis and patient mortality remains somewhat controversial. Several observational studies have shown improved patient survival with higher levels of delivered dialysis dose. However, several other unmeasured variables, changes in patient mix or medical management may have impacted on this reported difference in mortality. The current study of a U.S. national sample of 2,311 patients from 347 dialysis units estimates the relationship of delivered hemodialysis dose to mortality, with a statistical adjustment for an extensive list of comorbidity/risk factors. Additionally this study investigated the existence of a dose beyond which more dialysis does not appear to lower mortality. We estimated patient survival using proportional hazards regression techniques, adjusting for 21 patient comorbidity/risk factors with stratification for nine Census regions. The patient sample was 2,311 Medicare hemodialysis patients treated with bicarbonate dialysate as of 12/31/90 who had end-stage renal disease for at least one year. Patient follow-up ranged between 1.5 and 2.4 years. The measurement of delivered therapy was based on two alternative measures of intradialytic urea reduction, the urea reduction ratio (URR) and Kt/V (with adjustment for urea generation and ultrafiltration). Hemodialysis patient mortality showed a strong and robust inverse correlation with delivered hemodialysis dose whether measured by Kt/V or by URR. Mortality risk was lower by 7% (P = 0.001) with each 0.1 higher level of delivered Kt/V. (Expressed in terms of URR, mortality was lower by 11% with each 5 percentage point higher URR; P = 0.001). Above a URR of 70% or a Kt/V of 1.3 these data did not provide statistical evidence of further reductions in mortality. In conclusion, the delivered dose of hemodialysis therapy is an important predictor of patient mortality. In a population of dialysis patients with a very high mortality rate, it appears that increasing the level of delivered therapy offers a practical and efficient means of lowering the mortality rate. The level of hemodialysis dose measured by URR or Kt/V beyond which the mortality rate does not continue to decrease, though not well defined with this study, appears to be above current levels of typical treatment of hemodialysis patients in the U.S.

Nutrition in end-stage renal disease

In summary, it is evident that malnutrition is highly prevalent in ESRD patients. This is clearly related to multiple factors encountered during the pre-dialysis stage, as well as during maintenance dialysis therapy. A body of evidence highlights the existence of relationship between malnutrition and outcome in this patient population. Several preliminary studies suggest that interventions to improve the poor nutritional status of the ESRD patients may actually improve the expected outcome in these patients, although their long-term efficacy is not well established. It is therefore important to emphasize that malnutrition is a major co-morbid condition in the ESRD population and that the nutritional status and the treatment parameters of these patients should be altered to improve not only the mortality outcome of ESRD patients but also their quality of life.

Serum albumin in continuous peritoneal dialysis: its predictors and relationship to urea clearance

We investigated the predictors of serum albumin and the relationship between serum albumin and urea kinetic indices in continuous peritoneal dialysis (CPD). In a training set (TS) of 143 urea kinetic studies performed in 92 CPD patients, stepwise logistic regression identified high/high-average peritoneal solute transport, diabetes, advanced age and high daily drain volume normalized by body water as predictors of low serum albumin (< 35 g/liter). This analysis was then substantiated in a validation set (VS) of 187 kinetic studies performed in another 102 CPD patients. The calculated area under the receiver operating characteristic (ROC) curve by this logistic regression model was 0.782 (95% CI, 0.745 to 0.819). Logistic regression was repeated in the TS using only the first kinetic study from each patient, and it identified high/high-average peritoneal solute transport, diabetes, and advanced age as predictors of low albumin. Using only the first kinetic study from each patient in the VS, the second logistic regression model calculated an area under the ROC curve equal to 0.850 (95% CI, 0.810 to 0.890). The relative risk (RR) of serum albumin < 35 g/liter was computed for all kinetic studies after combining the TS and the VS and using non-diabetic CPD subjects aged < or = 61 years with low/low average peritoneal solute transport as the reference group. The RR with only one risk factor present ranged from 1.076 (age > 61 years) to 6.792 (high/high-average transport). The RR with two risk factors present ranged from 5.200 to 9.729. The RR with all three risk factors present was 9.100 (95% CI, range 3.923 to 21.111). A subset of 37 CPD patients had a second urea kinetic study 8 +/- 5 months after an increase in the amount of dialysis due to low urea clearance and/or uremic symptoms. The weekly KT/V urea increased from 1.40 +/- 0.24 to 2.10 +/- 0.31 after the increase in the CPD dose. With the increase in dialysis, the protein catabolic rate increased substantially; however, the mean serum albumin remained stable (from 33.9 +/- 4.6 to 33.3 +/- 6.2 g/liter; decrease 18; increase 15; same 4). In comparison to the subjects who had a decrease in serum albumin after the increase in KT/V, those with the increase in serum albumin were younger (44.2 +/- 11.2 vs. 54.3 +/- 16.2 years, P = 0.044) and had a higher serum urea after the increase in the dose of CPD (22.4 +/- 7.8 vs. 17.0 +/- 6.0 mmol/liter, P = 0.037). We conclude that the major predictors of low serum albumin in CPD are advanced age, diabetes, and high/high-average peritoneal solute transport, but not urea kinetic studies. An increase in the dose of dialysis does not cause a consistent rise in serum albumin in underdialyzed CPD subjects. However, a subset of younger patients may be able to increase their serum albumin in response to the increase in KT/V.

The impact of anemia on cardiomyopathy, morbidity, and and mortality in end-stage renal disease

To determine the possible association between anemia and clinical and echocardiographic cardiac disease, a cohort of 432 end-stage renal disease patients (261 on hemodialysis and 171 on peritoneal dialysis) who started dialysis therapy between 1982 and 1991 were followed prospectively for an average of 41 months. Baseline demographic, clinical, and echocardiographic assessments were performed, as well as monthly serial clinical and laboratory tests while the patients were on dialysis therapy. The mean (+/-SD) hemoglobin level during dialysis therapy was 8.8 +/- 1.5 g/dL. After adjusting for age, diabetes, and ischemic heart disease, as well as for blood pressure and serum albumin levels measured serially, each 1 g/dL decrease in mean hemoglobin was independently associated with the presence of left ventricular dilatation on repeat echocardiogram (odds ratio, 1.46; P = 0.018) and the development of de novo (relative risk [RR] = 1.28; P = 0.018) and recurrent (RR = 1.20; P = 0.046) cardiac failure. In addition, each 1 g/dL decrease in the mean hemoglobin level was independently associated with mortality while the patients were on dialysis therapy (RR = 1.14; P = 0.024). Anemia had no independent association with the development of ischemic heart disease while the patients were on dialysis therapy. Anemia, an easily reversible feature of end-stage renal disease, is an independent risk factor for clinical and echocardiographic cardiac disease, as well as mortality in end-stage renal disease patients.

Self-delivery of hemodialysis care: a therapy in itself

Patient autonomy, sense of control, and well-being are thought to be enhanced by self-care hemodialysis as a therapy for end-stage renal disease. Dialysis in a satellite setting reduces travel time and can diminish therapy intrusiveness. Health-related quality of life (HRQOL), in terms of functional status and well-being, was measured in a group of patients trained for self-care, and then measured again after these patients were transferred to a satellite unit. Comparison was made with an age- and comorbidity-matched cohort of full-care patients. Patients trained for self-care tended to score higher than the full-care patients in the psychosocial domains of HRQOL, such as role function, social function, and emotional well-being, before and after transfer to the satellite unit. Physiological measurements did not differ significantly between groups at any time during the study, indicating that differences in HRQOL were not attributable to differences in metabolic stability. We conclude that patients trained for self-care hemodialysis experience better subjective quality of life than their full-care counterparts. This study highlights both the usefulness of measuring HRQOL as an outcome of hemodialysis therapy and the potential benefits of therapies such as self-care and satellite dialysis.

Folate status is the major determinant of fasting total plasma homocysteine levels in maintenance dialysis patients

Limited data are available on the determinants of homocysteinemia or the association between plasma homocysteine (Hcy) levels and prevalent cardiovascular disease (CVD) in maintenance dialysis patients. We assessed etiology of renal failure, residual renal function and dialysis adequacy-related variables, and vitamin status, as determinants of fasting total plasma homocysteine (Hcy) in 75 maintenance dialysis patients. We also assessed the potential interactive effect on plasma Hcy of folate status and a common mutation (ala to val; homozygous val-val frequency approximately 10%) in methylenetetrahydrofolate reductase (MTHFR), a folate-dependent enzyme crucial for the remethylation of homocysteine (Hcy) to methionine. Lastly, we evaluated whether the Hcy levels differed amongst these patients in the presence or absence of prevalent CVD, after adjustment for the traditional CVD risk factors. Fasting total plasma Hcy, folate, pyridoxal 5'-phosphate (PLP; active B6), B12, creatinine, glucose, total and HDL cholesterol levels, and presence of the ala to val MTHFR mutation were determined, and clinical CVD and CVD risk factor prevalence were ascertained. General linear modelling/analysis of covariance revealed: (1) folate status and serum creatinine were the only significant independent predictors of fasting Hcy; (2) there was a significant interaction between presence of the val mutation and folate status, i.e., among patients with plasma folate below the median (< 29.2 ng/ml), geometric mean Hcy levels were 33% greater (29.0 vs. 21.8 microM, P = 0.012) in the pooled homozygotes (val-val) and heterozygotes (ala-val) for the ala to val mutation, vs. normals (ala-ala); (3) there was no association between prevalent CVD and plasma Hcy. Given potentially intractable survivorship effects, prospective cohort studies will be required to clarify the relationship between plasma Hcy or any putative CVD risk factor, and incident CVD in dialysis patients. If a positive association between plasma Hcy and incident CVD can be established in maintenance dialysis patients, the current data provide a rationale for additional folic acid supplementation in this patient population.

Effects of dietary protein restriction on the progression of advanced renal disease in the Modification of Diet in Renal Disease Study

Patients with advanced renal disease randomized to the very low-protein diet group in the Modification of Diet in Renal Disease (MDRD) Study had a marginally (P = 0.066) slower mean glomerular filtration rate (GFR) decline compared with patients randomized to the low-protein diet group. The objective of these secondary analyses was to determine the relationship between achieved, in addition to prescribed, dietary protein intake and the progression of advanced renal disease. A randomized controlled trial was conducted in patients with chronic renal diseases of diverse etiology. The average follow-up was 2.2 years. Fifteen university hospital outpatient nephrology practices participated in the study, which comprised 255 patients aged 18 to 70 years with a baseline GFR 13 to 24 mL/min/1.73 m2 who participated in MDRD Study B. Patients with diabetes requiring insulin were excluded. The patients were given a low-protein (0.58 g/kg/d) or very low-protein (0.28 g/kg/d) diet supplemented with keto acids-amino acids (0.28 g/kg/d). Outcomes were measured by comparisons of protein intake from food or from food and supplement between randomized groups, and correlations of protein intake with rate of decline in GFR and time to renal failure or death. Comparison of the randomized groups showed that total protein intake from food and supplement was lower (P < 0.001) among patients randomized to the very low-protein diet (0.66 g/kg/d) compared with protein intake from food only in patients randomized to the low-protein diet (0.73 g/kg/d). In correlational analyses, we combined patients assigned to both diets and controlled for baseline factors associated with a faster progression of renal disease. A 0.2 g/kg/d lower achieved total protein intake (including food and supplement) was associated with a 1.15 mL/min/yr slower mean decline in GFR (P = 0.011), equivalent to 29% of the mean GFR decline. After adjusting for achieved total protein intake, no independent effect of prescription of the keto acid-amino acid supplement to slow the GFR decline could be detected. If the GFR decline is extrapolated until renal failure, a patient with a 29% reduction in the rate of GFR decline would experience a 41% prolongation in the time to renal failure. Additional analyses confirmed a longer time to renal failure in patients with lower total protein intake. In conclusion, these secondary analyses of the MDRD Study suggest that a lower protein intake, but not the keto acid-amino acid supplement, retards the progression of advanced renal disease. In patients with GFR less than 25 mL/min/1.73 m2, we suggest a prescribed dietary protein intake of 0.6 g/kg/d.