Mortality In Chronic Hemodialysis Patients Research Articles

Blood Monocyte Count Is a Predictor of Total and Cardiovascular Mortality in Hemodialysis Patients

An increase in white blood cell (WBC) count is an independent predictor of mortality in hemodialysis (HD) patients. However, few studies have assessed the association of specific WBC subtypes with mortality. We prospectively studied the predictive value of WBC subtypes for total and cardiovascular death in 333 HD patients (age 63 ± 12 years; HD duration 129 ± 109 months) during a 40-month of follow-up. There was a significant and positive correlation between highly sensitive C-reactive protein and neutrophil (r = 0.28, p < 0.01) and monocyte (r = 0.20, p < 0.01) counts by a non-parametric Spearman rank analysis. Blood monocyte counts were significantly correlated inversely with ankle-brachial pressure index (r = –0.24, p < 0.01). Kaplan-Meier analysis revealed that basal neutrophil (>4,060/μl) and monocyte (>270/μl) counts in the highest tertile had a significantly lower survival rate compared to the middle and the lowest tertiles, respectively (p < 0.03). Cox hazards analysis after adjustment for other conventional risk factors revealed that monocyte counts of >270/μl became a determinant of total death compared with those of <180/μl (hazards ratio 1.98 [1.10–3.57], p = 0.02). In contrast, neutrophil and lymphocyte counts were not associated with mortality. Our findings suggest that an increased blood monocyte count is an independent predictor of long-term mortality in chronic HD patients.

N-terminal Pro-B–Type Natriuretic Peptide (NT-proBNP) Concentrations in Hemodialysis Patients: Prognostic Value of Baseline and Follow-up Measurements

Increased N-terminal pro-B-type natriuretic peptide (NT-proBNP) concentrations are associated with increased cardiovascular mortality in chronic hemodialysis patients. Previous studies focused on prevalent dialysis patients and examined single measurements of NT-proBNP in time. We measured NT-proBNP concentrations in 2990 incident hemodialysis patients to examine the risk of 90-day and 1-year mortality associated with baseline NT-proBNP concentrations. In addition, we calculated the change in concentrations after 3 months in a subset of 585 patients to examine the association between longitudinal changes in NT-proBNP and subsequent mortality. Increasing quartiles of NT-proBNP were associated with a monotonic increase in 90-day [quartile 1, referent; from quartile 2 to quartile 4, hazard ratio (HR) 1.7-6.3, P < 0.001] and 1-year (quartile 1, referent; from quartile 2 to quartile 4, HR 1.7-4.9, P < 0.001) all-cause mortality. After multivariable adjustment, these associations remained robust. When examined using a multivariable fractional polynomial, increased NT-proBNP concentrations were associated with increased 90-day (HR per unit increase in log NT-proBNP 1.5, 95% CI 1.3-1.7) and 1-year (HR per unit increase in log NT-proBNP 1.4, 95% CI 1.3-1.5) all-cause mortality. In addition, patients with the greatest increase in NT-proBNP after 3 months of dialysis had a 2.4-fold higher risk of mortality than those with the greatest decrease in NT-proBNP. NT-proBNP concentrations are independently associated with mortality in incident hemodialysis patients. Furthermore, the observation that longitudinal changes in NT-proBNP concentrations were associated with subsequent mortality suggests that monitoring serial NT-proBNP concentrations may represent a novel tool for assessing adequacy and guiding therapy in patients initiating hemodialysis.

Is depression a risk factor for mortality in chronic hemodialysis patients?

The present study was conducted to assess the association between depressive symptomatology and mortality in chronic hemodialysis. A cohort of 40 patients was followed for a median period of 10.5 months. The Beck Depression Inventory was used to classify patients as exposed to depression (Beck Depression Inventory score > 14) or not (Beck Depression Inventory < or = 14). Kaplan-Meier survival curves were used to compare the mortality rate between the two groups. The effects of potential confounding factors were adjusted using Cox proportional hazards model. After 24 months of follow-up, survival rates were 39% for exposed and 95% for non-exposed patients (p = 0.029). The Cox proportional hazards model showed results similar to those of the bivariate analysis, indicating that depressive symptomatology tended to be associated with mortality (HR = 6.5, 95%CI: 0.8-55.6; p = 0.085). Other study variables, including age, concurrent systemic diseases, and biochemical markers, were not significantly associated with mortality. Exposed patients remained on dialysis longer and received kidney transplants less frequently (9% vs. 50% for non-exposed patients). When kidney transplantation was included in the Cox regression model, the hazard ratio of mortality for exposed as compared to non-exposed patients lost statistical significance (HR = 4.5; 95%CI: 0.5-40.0; p = 0.17). Our study suggests that the presence of depressive symptoms may act as an independent risk factor for mortality in chronic hemodialysis patients. However, this finding needs further investigations.

Infective endocarditis in haemodialysis patients: 16-year experience at one institution.

Objectives. To ascertain the characteristics, outcomes and correlates of mortality in chronic haemodialysis patients with confirmed infective endocarditis (IE).Methods. Patients were identified by computerized discharge diagnosis and chart review of admissions to Saint Louis University hospital from January 1990 through January 2006. Modified Duke Criteria were retrospectively applied to confirm the diagnosis of IE. Survivors and non-survivors were compared to identify clinical correlates of IE mortality.Results. We identified 59 patients with IE who had received dialysis for a mean duration of 52.9 ± 58.0 months prior to IE diagnosis. Dialysis access comprised 28 (47.5%) catheters, 26 (44.1%) arteriovenous grafts, 3 (5.1%) arteriovenous fistulas and 2 (3.4%) life sites. The causative organisms were MRSA in 15 (25%), MSSA 12 (20%), S. Epidermidis 10 (17%), Enterococci 8 (14%), multi-organism 6 (10%), gram negative 2 (3%) and VRE 1 (2%). Valves involved were mitral valve in 37 (63%), aortic valve in 10 (17%), tricuspid valve in 3 (5%) and multiple valves in 8 (13%) cases. Patient mortality was 28.8% (n = 17) during hospitalization, 37.9% (n = 22) at 30 days and 63.1% (n = 36) at 1 year. In multivariable logistic regression, the adjusted odds ratio of in-hospital mortality was 3.6-fold higher in those with IE and arteriovenous grafts (P = 0.04, 95% CI 1.04–12.27) compared to other forms of dialysis access.Conclusion. Mortality of IE remains high, despite the availability of potent antibiotics. Patients with arteriovenous grafts who develop IE may face increased risk for in-hospital mortality, perhaps reflecting difficulty eradicating endovascular infection if a graft is involved.

Relation between Access Blood Flow and Mortality in Chronic Hemodialysis Patients

Access blood flow (Qa) measurement is a potentially important determinant of systemic hemodynamics in hemodialysis patients. High Qa may contribute to left ventricular dilation and high output heart failure. On the other hand, low Qa might lead to underdialysis, which is associated with adverse outcomes. In this retrospective study of incident chronic hemodialysis patients treated in three Canadian cities (Edmonton, Calgary, and Halifax), the hypothesis that extremes of Qa(low or high) would be associated with increased mortality was tested. The distribution of Qa was not Gaussian, and therefore Qa was log-transformed in analyses that treated it as a continuous variable. Qa was classified into categories defined by cutpoints of 500, 1000, 1500, and 2000 ml/min. Univariate and multivariate Cox proportional hazard models were performed to examine the relation between Qa and all-cause mortality. Patients were followed from the date of Qa measurement until death; follow-up was discontinued at loss to follow-up, kidney transplantation, or end of study. Of 820 participants, those with lower levels of Qa tended to be older and to have more comorbidities. During the median follow-up period of 28 mo, 206 (25.1%) participants died and 101 (12.3%) patients received a kidney transplant. When only baseline measures of Qa were considered, there was significant association between Qa and mortality [hazard ratio (HR) per unit increase in logQa 0.81, 95% confidence interval (CI) 0.67, 0.97; adjusted HR per unit increase in logQa 0.90, 95% CI 0.72, 1.11]. The adjusted risk of mortality was similar between the different categories of baseline Qa before and after adjustment for demographic characteristics, comorbidity, and access type. In analyses that included all Qa measurements per patient as a time-varying covariate, the adjusted association between Qa and death remained nonsignificant, with no evidence of increased mortality at higher Qa (HR per unit increase in logQa 0.82, 95% CI 0.67, 1.01, P = 0.066). The findings of this study do not suggest an increased risk of death at higher levels of Qa, Further studies would be needed to confirm an increased risk of death at lower Qa.

Prognostic value of heart rate variability in patients with renal failure on hemodialysis

Background In patients with renal failure on hemodialysis cardiovascular disease is a major cause of death. It has been reported that diminished heart rate variability (HRV) relates to the unfavorable prognosis in post-infarction and/or heart failure patients. However, the prognostic value of HRV in hemodialysis patients has not been fully established. Methods and results Time- and frequency-domain analysis of HRV on 24-hour ambulatory electrocardiography recording was assessed prospectively in 383 chronic hemodialysis patients (220 men and 163 women, mean age 57 ± 13 years, ejection fraction 65 ± 12%). During 2110 ± 903 days of follow up, 146 patients died (31 congestive heart failure, 13 fatal myocardial infarction, 13 sudden deaths, 26 stroke, and 63 non-cardiovascular deaths). A Cox univariate analysis identified the following factors as predictors of both all-cause and cardiovascular death: age, gender, ejection fraction, presence of diabetes, and HRV parameters calculated in the time- and frequency-domain. In multivariate analysis, a low standard deviation of all normal RR intervals (SDNN) value was the strongly associated with both all-cause and cardiovascular death (hazard ratios [95% confidence intervals] 0.988 [0.982–0.994] and 0.984 [0.974–0.993], respectively). From Kaplan–Meier survival curves, the incidence of all-cause and cardiovascular death was much greater in patients with a low SDNN (< 75 msec), even after adjusting for the presence of diabetes ( P < 0.0001). Conclusions Decreased HRV on 24-hour ambulatory electrocardiography is an independent predictor of mortality in chronic hemodialysis patients.

Inflammatory Marker but Not Adipokine Predicts Mortality among Long-Term Hemodialysis Patients

Aims: chronic inflammation contributes significantly to the morbidity and mortality of chronic hemodialysis patients. A recent research has shown that adipokines were associated with inflammation in these patients. We aim to investigate whether biomarkers of inflammation, adipokines, and clinical features can predict the outcome of hemodialysis patients. Materials and methods: we enrolled 181 hemodialysis patients (men: 97, mean age: ) and analyzed predictors of long-term outcomes. Results: during the 3-year followup period, 41 patients died; the main causes of death were infection and cardiovascular disease. Elevated serum levels of hsCRP and albumin and advanced age were highly associated with death (all ). Leptin and adiponectin levels were not significantly different between deceased patients and survivors. Cox-regression analysis indicated that age, diabetes, albumin level, and hsCRP were independent factors predicting mortality. Conclusion: the presence of underlying disease, advanced age, and markers of chronic inflammation is strongly related to survival rate in long-term hemodialysis patients.

Antibodies to the Platelet Factor 4-Heparin Complex and Mortality in Chronic Hemodialysis Patients.

Background: Heparin-induced thrombocytopenia is a serious complication of heparin therapy that can lead to thromboembolism, cardiovascular events or death. Patients with this disorder develop antibodies to the platelet factor 4-heparin (PF4-H) complex. Hemodialysis patients are repeatedly exposed to heparin and are at risk for developing PF4-H antibodies. The clinical impact of asymptomatic PF4-H antibodies in patients on chronic hemodialysis is not known.Objective: To determine the association between asymptomatic PF4-H antibodies and mortality in a cohort of chronic hemodialysis patients repeatedly exposed to heparin.Methods: Pre-dialysis blood samples were drawn from 419 asymptomatic patients. All patients received unfractionated heparin (Baxter) while on dialysis. All samples were screened for PF4-H antibodies using an ELISA assay (GTI PF4 Enhanced, GTI Diagnostics). All positive and indeterminate samples were then tested using an IgG-specific PF4-H ELISA assay and a platelet serotonin-release assay. Participants were then followed up prospectively for thromboembolic events, cardiovascular events, or death.Results: During a median follow-up of 2.5 years there were 129 deaths. After controlling for important potential confounding variables, the relative risk of death was 2.92 (95% CI: 1.18-7.25; P= 0.02) in patients with IgG-specific PF4-H antibodies and 4.08 (95% CI: 1.26–13.2; P= 0.02) in patients with IgG-specific antibodies and an indeterminate serotonin-release assay. Conclusions: PF4-H antibody formation is associated with increased all-cause mortality in patients on chronic hemodialysis. Further investigation is needed to determine if anticoagulation with alternative agents would improve survival in this population.

Metabolic consequences of body size and body composition in hemodialysis patients

Small body mass index is associated with increased mortality in chronic hemodialysis patients. The reasons for this observation are unclear but may be related to body composition. This study aimed to investigate the body composition in chronic hemodialysis patients. The difference between body mass and the sum of muscle, bone, subcutaneous, and visceral adipose tissue masses, measured by whole body magnetic resonance imaging, was defined as the high metabolic rate compartment representing the visceral mass. Protein catabolic rate was calculated from urea kinetics. Forty chronic hemodialysis patients (mean age 54.7 years; 87.5% African Americans; 45% females) were studied. High metabolic rate compartment expressed in percent of body weight was inversely related to body weight (r=-0.475; P=0.002) and body mass index (r=-0.530; P<0.001). In a multiple linear regression model, protein catabolic rate was significantly correlated only with high metabolic rate compartment (r=0.616; P<0.001). Assuming that protein catabolic rate in addition to protein intake reflects urea and uremic toxin generation, it follows that high metabolic rate compartment is the major compartment involved in their generation. Consequently, uremic toxin production rate may be relatively higher in patients with low body weight and low body mass index as compared to their heavier counterparts. The poorer survival observed in smaller dialysis patients may be related to these relative differences.

Association between seroprevalence of anti-chlamydial antibodies and long-term cardiovascular mortality in chronic hemodialysis patients

Chlamydial infection has been suspected in the pathogenesis of ischemic heart disease. However, it remains undetermined if persistent chlamydial infection is related to cardiovascular mortality in regular hemodialysis (HD) patients. We measured Chlamydia pneumoniae (Cp) antibody seropositivity in 154 HD subjects (age 59 ± 11 years, time on HD 13 ± 7 years, male/female = 101/53), and prospectively examined an association between Cp antibody status and cardiovascular death for 56 months of follow-up. Seropositivity for Cp IgA and IgG antibodies at the entry of the study was 50.6 and 60.8%, respectively. There was no significant difference in age, time on HD, serum albumin, C-reactive protein (CRP) and interleukin-6 (IL-6) between those positive and negative for IgA antibodies. During follow-up over 56 months, 31 patients (20.1%) expired, 16 (55.2%) of them of cardiovascular causes. Serological IgA and IgG antibody positivity did not influence mortality, while multiple Cox proportional hazards analysis revealed that diabetes, ischemic changes on electrocardiogram, log-transformed CRP and intact parathyroid hormone were independent determinants of cardiovascular death. These observations suggest that serological Cp antibody status does not affect long-term cardiovascular mortality in chronic HD patients.

Influence of Hypertension on Cardiovascular Outcomes in Hemodialysis Patients

Cardiovascular disease is a leading cause of morbidity and mortality in chronic hemodialysis patients. Most patients with chronic kidney disease have hypertension and its prevalence remains high following renal replacement therapy. Early studies suggested that hypertension was a risk factor for total and cardiovascular mortality in chronic hemodialysis patients, but the results of more recent studies have caused experts to question these assertions. Systolic hypertension, widened pulse pressure, and nondipping may be better predictors of mortality compared to diastolic hypertension or increased mean arterial pressure. Hypertension in hemodialysis patients is a risk factor for left ventricular hypertrophy (LVH), diastolic dysfunction, and congestive heart failure; good blood pressure control may promote its regression. Atherosclerosis and ventricular arrhythmias may also be linked to hypertension. Thus blood pressure control with a focus on systolic pressure appears to be a prudent strategy to improve cardiovascular outcomes in hemodialysis patients.

Effect of increased convective clearance by on-line hemodiafiltration on all cause and cardiovascular mortality in chronic hemodialysis patients – the Dutch CONvective TRAnsport STudy (CONTRAST): rationale and design of a randomised controlled trial [ISRCTN38365125

BackgroundThe high incidence of cardiovascular disease in patients with end stage renal disease (ESRD) is related to the accumulation of uremic toxins in the middle and large-middle molecular weight range. As online hemodiafiltration (HDF) removes these molecules more effectively than standard hemodialysis (HD), it has been suggested that online HDF improves survival and cardiovascular outcome. Thus far, no conclusive data of HDF on target organ damage and cardiovascular morbidity and mortality are available. Therefore, the CONvective TRAnsport STudy (CONTRAST) has been initiated.MethodsCONTRAST is a Dutch multi-center randomised controlled trial. In this trial, approximately 800 chronic hemodialysis patients will be randomised between online HDF and low-flux HD, and followed for three years. The primary endpoint is all cause mortality. The main secondary outcome variables are fatal and non-fatal cardiovascular events.ConclusionThe study is designed to provide conclusive evidence whether online HDF leads to a lower mortality and less cardiovascular events as compared to standard HD.

Impact of carotid atherosclerosis on long-term mortality in chronic hemodialysis patients

Cardiovascular event is the major cause of mortality in patients on maintenance hemodialysis. We prospectively tested the predictive values of atherosclerotic parameters for all-cause and cardiovascular outcomes in 219 hemodialysis patients (age, 58 +/- 13 years; time on hemodialysis, 13 +/- 7 years; male/female, 144/75). We measured blood homocysteine (Hcy), ultrasound carotid artery intima media thickness (IMT) and % aortic wall calcification at L2/3 region [% of calcification index in the abdominal aortic wall (%ACI)] by computed tomography (CT) scan, and followed all patients for 5 years. During the follow-up periods, 54 patients (25%) died, 40 (74%) of them of cardiovascular causes. IMT was significantly higher in patients who expired (0.75 +/- 0.02 mm) than in those who survived (0.62 +/- 0.01 mm). IMT was significantly correlated with age (r = 0.47, P < 0.01) and %ACI (r = 0.27, P < 0.01). The survival rate during the observation was significantly lower in the final IMT third (58%) than in the first (90%) and the middle IMT third (80%) (P < 0.01). Multivariate Cox proportional hazards analysis revealed that diabetes and IMT became independent determinants of all-cause and cardiovascular death. Adjusted hazards ratios of all-cause and cardiovascular mortality for an increase of 0.1 mm in IMT were 1.31 (95% CI, 1.07 to 1.59) and 1.41 (95% CI, 1.12 to 1.76). In contrast, %ACI at abdominal aorta and blood Hcy did not affect their 5-year mortality. These findings suggested that measurement of carotid artery IMT is useful for predicting long-term mortality in patients receiving maintenance hemodialysis.

Association of depression with malnutrition in chronic hemodialysis patients

Background:Depression is the most common psychological complication and may increase mortality in chronic hemodialysis patients. Because depression could be associated with poor oral intake and activation of proinflammatory cytokines that could further increase mortality by malnutrition, we investigated the relation between depression and nutritional status in chronic hemodialysis patients. Methods:Sixty-two Korean patients completed the Beck Depression Inventory (BDI) questionnaire, and the diagnosis of depression was confirmed by Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria for major depressive disorder. Nutritional status was evaluated using serum albumin level, normalized protein catabolic rate, subjective global assessment (SGA), and anthropometric measurement. Results:Mean BDI score was 22.7 ± 11.4, and 35 patients (56.5%) had a BDI score greater than 21, which is the suggested cutoff score for the diagnosis of depression for the Korean population. Of 40 patients who had a score higher than 18 on the BDI, 34 patients met DSM-IV criteria for major depressive disorder. BDI score correlated negatively with a variety of nutritional parameters: serum albumin level (r = −0.47; P < 0.001), normalized protein catabolic rate (r = −0.32; P < 0.05), SGA (r = −0.47; P < 0.01), triceps skinfold thickness (r = −0.40; P < 0.05), midarm muscle circumference (r = −0.57; P < 0.01), and body mass index (r = −0.28; P < 0.05). Multiple regression analysis also identified BDI score as an independent determinant for all kinds of nutritional parameters. Conclusion:In patients on chronic hemodialysis therapy, depression is related closely to nutritional status and could be an independent risk factor for malnutrition.

Total hip bone mass predicts survival in chronic hemodialysis patients

Bone mass measurements are widely used to diagnose osteoporosis and identify patients at risk for fractures. Recent studies have shown that reduced bone mass is also predictive of all-cause and cardiovascular mortality in healthy postmenopausal women. Among chronic hemodialysis patients reduced bone mass resulting from the combined effects of age-related factors and renal osteodystrophy has been associated with vascular calcification. In this prospective study, we investigated the ability of bone mass measurements to predict mortality in chronic hemodialysis patients. Eighty eight patients underwent hip bone mass measurements by dual energy x-ray absorptiometry (DEXA) and were followed up for a mean of 3.5 years. Eleven patients received renal transplants and were therefore excluded. Forty of the remaining patients died, predominantly due to cardiovascular causes (43%). Cox regression analysis showed patient age, osteoporosis or osteopenia, and baseline average calcium x phosphate product (Ca x P) to be independently predictive of increased mortality. Patients with osteopenia or osteoporosis had a 3.3- and 4.3-fold increased risk of death, respectively. A Ca x P of >or=5.0 mmol2/L2 predicted a threefold increased risk of death. Previous renal transplantation predicted a lower mortality. This study has shown for the first time that reduced total hip bone mass is an independent predictor of all-cause mortality among chronic hemodialysis patients. Our findings suggest that reduced bone mass and elevated Ca x P may be involved in the pathogenesis of cardiovascular disease in these patients but further research is required to investigate the possible mechanisms for these associations.

Role of Vascular Access as a Risk Factor for Infections in Hemodialysis

Infections are a major cause of morbidity and mortality in chronic hemodialysis patients. This single center prospective study was carried out to determine the incidence and risk factors for infection in hemodialysis patients and plan appropriate strategies to reduce the risk of infection. A total of 84 consecutive patients who were initiated on hemodialysis over a 2-year period were followed until they either received a kidney transplant or died. In our hospital, as a policy, patients are offered hemodialysis as a bridge therapy to a kidney transplant. The mean duration of follow up was 3 months (range 1–11.8 months). The factors associated with at least one episode of infection were evaluated. Statistical analysis was done by multivariate stepwise logistic regression method. Fifty-one patients had a total of 57 episodes (67.8%) of infection. Of the 44 episodes of acute bacterial infections, vascular access exit site infection was the commonest followed by septicemia (13 patients, 29.5%). Staphylococcus aureus was the commonest bacterial isolate observed in 14 patients. On multivariate analysis, three risk factors for infection were identified: (1) nonarteriovenous fistula (AVF) vascular access for hemodialysis (p = 0.02), (2) increased number of hemodialysis sessions (p = 0.03), and (3) lower serum calcium level (p = 0.02). NonAVF vascular access was found to be the most important risk factor for infection in hemodialysis patients. Creation of an AV fistula, preferably at an early stage, appears beneficial for minimizing the risk of infection even in patients who are on short-term hemodialysis as a bridge therapy towards a kidney transplant.

Central aortic pressure augmentation in stable renal transplant recipients

Premature cardiovascular disease is the leading cause of death in renal transplant recipients and classical risk factors significantly underestimate the risk. The increased effect of arterial wave reflections on central arteries has recently been shown to be an important independent predictor of cardiovascular mortality in chronic hemodialysis patients. The aim of this study was to assess the contribution of several classical and potential non-classical cardiovascular risk factors on aortic pressure augmentation by the reflected arterial wave in stable renal transplant recipients. Using the non-invasive technique of pulse wave analysis aortic augmentation was investigated in 250 stable renal transplant recipients. Peripheral pulse waveforms were recorded from the radial artery. Central aortic waveforms were then generated and the aortic augmentation index calculated. In multivariate analysis, female sex (regression coefficient 7.5 +/- 1.7%; P < 0.001), heart rate (-4.8 +/- 0.5% per 10 beats/min; P < 0.001), mean arterial pressure (4.2 +/- 0.6% per 10 mm Hg; P < 0.001), the persistence of an arteriovenous fistula (4.1 +/- 1.3%; P < 0.005), total time on renal replacement therapy (3.8 +/- 0.9% per 10 years; P < 0.001), height (-3.1 +/- 0.8% per 10 cm; P < 0.001), immunosuppression with cyclosporine (2.8 +/- 1.3%; P < 0.005) and age (2.5 +/- 0.5% per 10 years; P < 0.001) were all important correlates of aortic augmentation index. Our findings suggest, to our knowledge for the first time, that both the presence of a functioning arteriovenous fistula and immunosuppressive treatment with cyclosporine are associated with an increased aortic augmentation index in renal transplant recipients and could, therefore, be potential reversible contributors to the high cardiovascular risk profile in these patients.

The role of the dietitian in a multicenter clinical trial of dialysis therapy: The hemodialysis (HEMO) study

The Hemodialysis (HEMO) Study is a randomized multicenter prospective clinical trial, supported by the National Institute of Diabetes, Digestive, and Kidney Diseases of the National Institutes of Health. The trial is designed to assess the effects of a standard versus higher dialysis dose and low versus high dialysis membrane flux on morbidity and mortality of chronic hemodialysis patients. The role of the dietitian in the HEMO Study is to support and maintain the nutritional status of randomized participants. To ensure participant safety, nutritional status is closely monitored by a variety of biochemical and participant-reported parameters. Serum albumin and equilibrated normalized protein catabolic rates are obtained monthly. Appetite assessment and dietary energy and protein intakes using a 2-day diet diary assisted recall are ascertained at baseline and on a yearly basis. Consumption of vitamins, minerals, and nutritional supplements, including oral enterals, tube feedings, and parenteral nutrition, is obtained at least once a year. In addition, anthropometry is performed at baseline and on a yearly basis. Prespecified changes in serum albumin level or body weight trigger action by the dietitian to prevent protein calorie malnutrition. The HEMO Study dietitians play a vital role in carrying out the nutrition program for the trial. The HEMO Study should provide important information about the natural history of the nutritional status of chronic hemodialysis patients and the impact of dialysis dose and dialysis membrane flux on these parameters.

Effect of dialysis membranes and middle molecule removal on chronic hemodialysis patient survival.

The type of dialysis membrane used for routine therapy has been recently shown to correlate with the survival of chronic hemodialysis patients. We examined whether this effect of dialysis membrane could be explained by differences in dialyzer removal of middle molecules using data from the 1991 Case Mix Adequacy Study of the United States Renal Data System. The sample analyzed included patients who had been treated by hemodialysis for 1 year or more, who were dialyzed with the 19 most commonly used dialyzers in 1991, and for whom delivered urea Kt/V could be calculated from predialysis and postdialysis blood urea nitrogen concentrations. Vitamin B12 (1,355 daltons) was used as a marker for middle molecules, and the clearance of vitamin B12 was estimated based on in vitro data. After adjustments for case mix, comorbidities, and urea Kt/V, the relative risk of mortality for a 10% higher calculated total cleared volume of vitamin B12 was 0.953 (P < 0.0001 v 1.000). Similar results were obtained when middle molecule removal was adjusted for body size. We conclude that both small and middle molecule removal indices appear to be independently associated with the risk of mortality in chronic hemodialysis patients. Differences in mortality when using different types of dialysis membrane may be explained by differences in middle molecule removal.

Reassessing the cardiac risk profile in chronic hemodialysis patients: a hypothesis on the role of oxidant stress and other non-traditional cardiac risk factors.

Cardiovascular disease is the single largest cause of mortality in the general population (1) and, as such, it is not surprising that it is also the leading cause of mortality in chronic hemodialysis patients, accounting for nearly half of all deaths in this population in the United States (2). Numerous studies have described the high prevalence of atherosclerotic cardiovascular disease (2,3) and congestive heart failure in the ESRD population (4,5), with these entities accounting for a great majority of cardiovascular mortality in the chronic hemodialysis population.