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

Prevalence of and factors associated with suboptimal care before initiation of dialysis in the United States

Despite improvements in dialysis care, the mortality of patients with end-stage renal disease (ESRD) in the United States remains high. Factors that thus far have received scant attention, but could significantly affect morbidity and mortality in dialysis patients, are the timing and quality of care before the initiation of dialysis (pre-ESRD). Data from the new version of the Health Care Financing Administration (HCFA) 2728 Form were used to examine the prevalence of and factors associated with hypoalbuminemia, severe anemia, and erythropoietin (EPO) use among 155,076 incident chronic dialysis patients in the United States between April 1, 1995 and June 30, 1997. At initiation of dialysis, the median serum albumin and hematocrit were 3.3 g/dl and 28%, respectively. Sixty percent of patients had a serum albumin below the lower limit of normal and 51% had a hematocrit <28%. Overall, only 23% had received EPO pre-ESRD. Among patients with hematocrit <28%, only 20% were receiving EPO, compared to 27% among patients with hematocrit > or =28%. In a multivariate analysis that adjusted for diabetes, functional status, and demographic, socioeconomic, and geographic factors, the odds ratios for hypoalbuminemia, hematocrit <28%, and lack of EPO use were higher for African-Americans, patients with non-private insurance or no insurance, and patients who were started on hemodialysis. There were also significant differences in odds ratios for these outcomes between different geographic regions in the United States. The high prevalence of pre-ESRD hypoalbuminemia, hematocrit <28%, and lack of EPO use suggests that the quality of pre-ESRD care in the United States is suboptimal. Improvement in pre-ESRD care could potentially improve outcomes among ESRD patients.

Incidence, prognosis, and etiology of end-stage liver disease in patients receiving home total parenteral nutrition

BACKGROUND

Elevations in liver function tests have been reported in patients receiving total parenteral nutrition (TPN). The clinical aspects of end-stage liver disease (ESLD) associated with the prolonged use of home TPN have not been fully clarified. In previous series patients with duodenocolostomies appeared to be at higher risk than persons with some jejunum or ileum remaining in situ.

METHODS

The records of 42 patients treated with home TPN for more than 1 year were examined. This constituted 283 person-years of home TPN. Patients with duodenocolostomies were examined as a separate group on the basis of the literature experience.

RESULTS

Six of 42 patients who received chronic home TPN had ESLD with 100% subsequent mortality, at an average of 10.8 +/- 7.1 months after the initial bilirubin elevation. Thirteen of 42 patients had superior mesenteric artery or vein thrombosis (SMT) leading to duodenocolostomy. In 8 of these 13 patients with SMT and underlying inflammatory or malignant disorder, 2 had ESLD. The remaining 5 SMT patients who had only minimal liver enzyme elevation over 13.6 +/- 6.7 (range 3 to 19) years of home TPN were significantly younger (36 +/- 7 years vs 64 +/- 13 years) and did not have underlying inflammation either by clinical diagnosis or as reflected in the high normal serum albumin level (> or = 4.0 g/dL). Despite their extreme short bowel syndrome and long exposure to home TPN, ESLD did not develop.

CONCLUSIONS

Approximately 15% of patients who receive prolonged TPN have ESLD with a high rate of morbidity and mortality. The combination of chronic inflammation and the short bowel syndrome appears to be necessary for the development of ESLD with prolonged home TPN.

Effect of aminoglycoside use on residual renal function in peritoneal dialysis patients

Residual renal function (RRF) is a major contributor to total solute clearance in peritoneal dialysis (PD) patients, and maintenance of RRF has been linked to decreased morbidity and mortality in PD. There have been few clinical studies examining the impact of factors that potentially affect RRF in PD. This is a prospective observational study that examines the effects of parenteral aminoglycosides, a common nephrotoxin in the general population, on RRF in a cohort of PD patients. Seventy-two patients from two Rhode Island PD units were observed over 4 years. Twenty-four-hour renal creatinine clearances and urine volumes were measured every 4 to 6 months. The patients were divided into three groups, depending on exposure to peritonitis and aminoglycoside use. Group I included patients without peritonitis who received no intravenous (IV) or intraperitoneal (IP) antibiotics. Group II included patients with peritonitis who received IV or IP penicillins, cephalosporins, vancomycin, or quinolones, but no aminoglycosides. Group III included patients with peritonitis who received IV or IP aminoglycosides for at least 3 days. Patients in group III had a more rapid decline in renal creatinine clearance (-0.66 +/- 0.58 mL/min/mon) than groups I and II (P < 0.005) and had a more rapid decline in daily urine volume (-74 +/- 62 mL/d/mon) than groups I and II (P < 0.01). We conclude that IV or IP aminoglycosides seem to increase the rapidity of decline in RRF in PD patients. In patients with solute clearance dependent on RRF, it seems reasonable to withhold aminoglycosides, especially if other antibiotics are available and appropriate.

High protein/energy vs. standard protein/energy nutritional regimen in the treatment of malnourished hemodialysis patients

Although malnutrition is frequently encountered in maintenance hemodialysis (MHD) patients, a clear method of treating this complication is still lacking. Failure of nutritional support regimens may be due to inadequate support of dietary needs. Therefore, a high vs. standard or low protein/energy dietary regimen was studied in malnourished MHD patients. A total of 18 malnourished MHD patients selected according to subjective global assessment (SGA)-scores and biochemical indicators of malnutrition (serum albumin <40 g/l, cholesterol <200 mg/dl, prealbumin <30 mg/dl; two out of three) were assigned to three treatment groups: (A: 45 kcal/kg/d and 1.5 g protein/kg/d; B: 35 kcal/kg/d and 1.2 g protein/kg/d; C: spontaneous intake supplemented with 10% of mean protein and energy intake). A and B received food supplements at appropriate dosing to reach the targeted nutritional intake. During 3-month follow-up nutrient intake was assessed by repeated 4-day dietary diaries. Compliance and tolerance was good in each group. Weight gain (1.2+/-0.4 kg) was observed in group A, but not in B and C. Serum albumin levels increased by 1.0+/-0.5 g/l in group A, but not in B and C. Prealbumin and cholesterol levels were unaffected. Weight change correlated with mean dietary energy intake, but not with mean dietary protein intake. We conclude that prescription of 45 kcal/kg/d and 1.5 g protein/kg/d may be necessary to achieve weight gain and improvement of nutritional indices in malnourished MHD pts. Oral food supplements can be used safely and effectively to increase nutrient intake to high levels in these patients.

Haemodialysis and peritoneal dialysis: metabolic alterations and nutritional status

In dialysis patients, malnutrition is an independent factor causing morbidity and mortality. Both inadequate alimentation and metabolic alterations, which involve nitrogen and energy metabolism, contribute to malnutrition. Future research must address the treatment of anorexia and inflammation-induced catabolism, as well as the evaluation of nutritional supplementation techniques and anabolic drugs.

Clinical and biochemical correlates of starting "daily" hemodialysis

BACKGROUND

Daily hemodialysis has been proposed to improve outcomes for patients with end-stage renal disease. There has been increasing evidence that daily hemodialysis might have potential advantages over intermittent dialysis. However, despite these potential advantages, daily hemodialysis is infrequently used in the United States, and published accounts on the technique are few.

METHODS

We describe patient outcomes after increasing their hemodialysis frequency from three to six times per week in a cohort of 72 patients treated at nine centers during 1972 to 1996. Analyses of predialysis blood pressure and laboratory parameters from 6 months before until 12 months after starting frequent hemodialysis used a repeated-measures statistical technique.

RESULTS

Predialysis systolic and diastolic blood pressures fell by 7 and 4 mm Hg, respectively, after starting frequent hemodialysis (P = 0.02). Reductions were greatest among patients being treated with antihypertensive medications, despite a reduction in their dosage of medications. Postdialysis weight fell by 1.0% within one month of starting frequent hemodialysis and improved control of hypertension. After the initial drop, postdialysis weight increased at a rate of 0.85 kg per six months. Serum albumin rose by 0.29 g/dl (P < 0.001) between months 1 to 12 of treatment with daily hemodialysis. Hematocrit rose by 3.0 percentage points (P = 0.02) among patients (N = 56) not treated with erythropoietin during this period. Two years after the start of daily hemodialysis, Kaplan-Meier analyses showed a patient survival of 93%, a technique survival of 77%, and an arteriovenous fistula patency of 92%. Vascular access patency was excellent despite more frequent use of the access.

CONCLUSIONS

These results suggest that in certain patients, daily hemodialysis might have advantages over three times per week hemodialysis.

Association of morbidity with markers of nutrition and inflammation in chronic hemodialysis patients: a prospective study

BACKGROUND

Numerous studies suggest a strong association between nutrition and clinical outcome in chronic hemodialysis (CHD) patients. Nevertheless, the pathophysiological link between malnutrition and morbidity remains to be clarified. In addition, recent evidence suggests that nutritional indices may reflect an inflammatory response, as well as protein-calorie malnutrition. In this study, we prospectively assessed the relative importance of markers of nutritional status and inflammatory response as determinants of hospitalization in CHD patients.

METHODS

The study consisted of serial measurements of concentrations of serum albumin, creatinine, transferrin, prealbumin, C-reactive protein (CRP), and reactance values by bio-electrical impedance analysis (BIA) as an indirect measure of lean body mass every 3 months over a period of 15 months in 73 CHD patients. Outcome was determined by hospitalizations over the subsequent three months following each collection of data.

RESULTS

Patients who required hospitalization in the three months following each of the measurement sets had significantly different values for all parameters than patients who were not hospitalized. Thus, serum albumin (3.93 +/- 0.39 vs. 3.74 +/- 0.39 g/dl), serum creatinine (11.0 +/- 3.7 vs. 9.1 +/- 3.5 mg/dl), serum transferrin (181 +/- 35 vs. 170 +/- 34 mg/dl), serum prealbumin (33.6 +/- 9.2 vs. 30.0 +/- 10.1 mg/dl), and reactance (50.4 +/- 15.6 vs. 43.0 +/- 13.0 ohms) were higher for patients not hospitalized, whereas CRP (0.78 +/- 0.89 vs. 2.25 +/- 2.72 mg/dl) was lower in patients who were not hospitalized. All differences were statistically significant (P < 0.05 for all parameters). When multivariate analysis was performed, serum CRP and reactance values were the only statistically significant predictors of hospitalization (P < 0.05 for both). When a serum CRP concentration of 0.12 mg/dl was considered as a reference range (relative risk 1.0), the relative risk for hospitalization was 7% higher (relative risk = 1.07) for a CRP concentration of 0.92 mg/dl and was 30% (relative risk = 1.30) higher for a CRP concentration of 3.4 mg/dl. When a reactance value of 70 ohms was considered as a reference range with a relative risk of 1.0, the relative risk of hospitalization increased to 1.09 for a reactance value of 43 ohms and further increased to 1.14 for a reactance value of 31 ohms.

CONCLUSIONS

The results of this study strongly indicate that both nutritional status and inflammatory response are independent predictors of hospitalization in CHD patients. CRP and reactance values by BIA are reliable indicators of hospitalization. Visceral proteins such as serum albumin, prealbumin, and transferrin are influenced by inflammation when predicting hospitalization. When short-term clinical outcomes such as hospitalizations are considered, markers of both inflammation and nutrition should be evaluated.

The low molecular weight apo(a) phenotype is an independent predictor for coronary artery disease in hemodialysis patients: a prospective follow-up

Patients with end-stage renal disease treated by hemodialysis have a tremendous risk for cardiovascular complications that cannot be explained by traditional atherosclerosis risk factors. Lipoprotein(a) (Lp(a)), a risk factor for these complications in the general population, is significantly elevated in these patients. In this study, it was determined whether Lp(a) and/or the genetically determined apo(a) phenotype are risk predictors for the development of coronary artery disease in these patients. A cohort of 440 unselected hemodialysis patients were followed for a period of 5 yr independent of the cause of renal disease, duration of preceding treatment, and the preexistence of coronary artery disease at study entry. Coronary events defined as definite myocardial infarction, percutaneous transluminal coronary angioplasty, aortocoronary bypass, or a stenosis >50% in the coronary angiography were the main outcome measure. Sixty-six (15%) of the 440 patients suffered a coronary event during follow-up. In univariate analysis, patients with events were significantly older and showed a trend to lower HDL cholesterol concentrations, and higher apolipoprotein B and Lp(a) concentrations without reaching significance. Apo(a) phenotypes of low molecular weight, however, were significantly more frequent in patients with compared to those without events (43.9% versus 21.9%, P<0.001). The other lipids, lipoproteins, and apolipoproteins were similar in both groups. Multiple Cox proportional hazards regression analysis found age and the apo(a) phenotype to be the best predictors for coronary events during the observation period, independent of whether patients with a preexisting coronary artery disease or an age >65 yr at the study entry or both were excluded from the analysis. Diabetes mellitus was a risk factor only in presence of a low molecular weight apo(a) phenotype. The genetically determined apo(a) phenotype is a strong and independent predictor for coronary events in hemodialysis patients. Apo(a) phenotyping might be helpful to identify hemodialysis patients at high risk for coronary artery disease.

Double-blind, placebo-controlled study of growth hormone treatment in elderly patients undergoing chronic hemodialysis: anabolic effect and functional improvement

Elderly patients with end-stage renal disease often have protein and/or caloric malnutrition that severely affects general well-being and mortality. Uremia is associated with resistance to the action of growth hormone (GH). This resistance could be of clinical importance in elderly dialysis patients. In the present study, the effects of GH treatment were assessed in elderly patients receiving chronic hemodialysis. Twenty hemodialysis patients with a mean age of 71.7 years (range, 53 to 92 years) were included on a 6-month, randomized, double-blind, placebo-controlled trial of GH treatment. The dose of GH was 66.7 microgram/kg, administered subcutaneously three times weekly immediately after each dialysis session. Body composition was measured using total-body potassium levels, computed tomography of the lower leg, and bioelectrical impedance analysis. Serum albumin concentrations and handgrip strength were also measured. GH treatment increased the serum concentration of insulin-like growth factor-I (IGF-I), IGF-I/IGF-binding protein-3 ratio, fat-free mass, and the serum concentration of albumin compared with placebo. The number of patients with serum albumin levels less than 40 g/L was reduced by a factor of three in the GH-treated group. Handgrip strength increased in response to GH treatment compared with placebo. Six months of GH treatment in elderly hemodialysis patients produced anabolic effects, with improved muscle performance. Also, the number of patients with low albumin levels was markedly reduced, indicating improved nutritional status and/or attenuated catabolism. These are all important beneficial effects for individual patient outcomes.

Growth during maintenance hemodialysis: impact of enhanced nutrition and clearance

Growth of children during maintenance hemodialysis has been reported to be uniformly poor, with a mean annual loss of 0.4 to 0.8 SD in height. We adopted an intensive program of closely monitored energy and protein intake with dialysis urea clearances exceeding conventional recommendations. Twelve prepubertal or early pubertal children (aged 7 months to 14 years) were monitored for an average of 2.2 years (range 4 to 81 months) while receiving maintenance hemodialysis. These children received an average of 90.6% and 155.9% of their recommended energy and protein nutritional intake, respectively. With a prescribed urea clearance of 5 mL/kg/min, we achieved a mean single treatment urea clearance normalized for total body water of 2.00, a urea reduction ratio of 84.7%, and an average time of hemodialysis of 14.8 h/wk, all well beyond current guidelines. Over the course of dialysis treatment, the improvement in height SD score was+0.31 SD/y (+0.32 excluding the 2 children treated with recombinant human growth hormone). Normal growth was achieved without overt obesity and was associated with normal pubertal growth spurt. These findings suggest that the combination of increased dialysis and adequate nutrition can promote normal growth in children treated with long-term hemodialysis.

Relationship between urea reduction ratio, demographic characteristics, and body weight for patients in the 1996 National ESRD Core Indicators Project

The 1996 Health Care Financing Administration's (HCFA) Core Indicators Project for in-center, hemodialysis patients collects information on the quality of care delivered in four clinical areas that were anticipated to predict patient outcomes. Included among these clinical performance measurements is the delivered dose of hemodialysis, measured by the fractional reduction of urea achieved during a single hemodialysis session (urea reduction ratio [URR]). A random sample (N = 7,310) of adult (aged > or =18 years), in-center hemodialysis patients was selected, and a one-page data collection form for each patient was sent to the dialysis facility in which care was provided during the last quarter of 1995. The dialysis facilities provided information for 6,861 (94%) patients, and at least one paired predialysis and postdialysis blood urea nitrogen (BUN) concentration was reported for 6,655 (97%) of these patients. The URR of this cohort was 65.5% +/- 8.0% (mean +/- SD), and 41% of patients had a URR less than 65%. The mean dialysis session length was 203 minutes, and more than half of the patients received dialysis with a dialyzer membrane with a KUf less than 10 mL/mm Hg/h. The patients with a URR less than 65% had a mean body weight approximately 10 kg greater than patients with a URR of 65% or greater. This relationship was present for all demographic characteristics studied, including age, gender, race, and primary cause of end-stage renal disease (ESRD). Patients receiving dialysis for less than 6 months were more likely to have a URR less than 65% than patients on dialysis for longer periods. By multivariate analysis, variables significantly associated with a delivered URR less than 65% were body weight in the heaviest quartile (odds ratio [OR] = 6.1), male gender (OR = 2.6), on dialysis therapy less than 6 months (OR = 2.5), youngest quartile of age (<49 years) (OR = 2.0), lowest quartile of serum albumin values less than 3.6 g/dL (bromcresol green method) or less than 3.3 g/dL (bromcresol purple method) (OR = 1.6), black (OR = 1.5), dialyzed with a dialyzer KUf less than 20 mL/mm Hg/h (OR = 1.8), lowest quartile hematocrit (<29.7%) (OR = 1.2), and shorter dialysis session length (OR = 1.02/min). In conclusion, both patient-specific demographic variables and treatment-specific parameters are significantly associated with ESRD patients receiving a URR less than 65%. Furthermore, these data suggest statistically significant linkages between the delivered dose of hemodialysis and other independent outcome predictors such as serum albumin concentration. Prospective study is required to determine whether intervention strategies to improve the delivered dose of hemodialysis will affect this outcome predictor or whether serum albumin and dialysis dose share a common cause not amenable to increasing the URR.

Hematocrit level and associated mortality in hemodialysis patients

Although a number of clinical studies have shown that increased hematocrits are associated with improved outcomes in terms of cognitive function, reduced left ventricular hypertrophy, increased exercise tolerance, and improved quality of life, the optimal hematocrit level associated with survival has yet to be determined. The association between hematocrit levels and patient mortality was retrospectively studied in a prevalent Medicare hemodialysis cohort on a national scale. All patients survived a 6-mo entry period during which their hematocrit levels were assessed, from July 1 through December 31, 1993, with follow-up from January 1 through December 31, 1994. Patient comorbid conditions relative to clinical events and severity of disease were determined from Medicare claims data and correlated with the entry period hematocrit level. After adjusting for medical diseases, our results showed that patients with hematocrit levels less than 30% had significantly higher risk of all-cause (12 to 33%) and cause-specific death, compared to patients with hematocrits in the 30% to less than 33% range. Without severity of disease adjustment, patients with hematocrit levels of 33% to less than 36% appear to have the lowest risk for all-cause and cardiac mortality. After adjusting for severity of disease, the impact of hematocrit levels of 33% to less than 36% is vulnerable to the patient sample size but also demonstrates a further 4% reduced risk of death. Overall, these findings suggest that sustained increases in hematocrit levels are associated with improved patient survival.

Prevalence and clinical outcome associated with preexisting malnutrition in acute renal failure: a prospective cohort study

Malnutrition is a frequent finding in hospitalized patients and is associated with an increased risk of subsequent in-hospital morbidity and mortality. Both prevalence and prognostic relevance of preexisting malnutrition in patients referred to nephrology wards for acute renal failure (ARF) are still unknown. This study tests the hypothesis that malnutrition is frequent in such clinical setting, and is associated with excess in-hospital morbidity and mortality. A prospective cohort of 309 patients admitted to a renal intermediate care unit during a 42-mo period with ARF diagnosis was studied. Patients with malnutrition were identified at admission by the Subjective Global Assessment of nutritional status method (SGA); nutritional status was also evaluated by anthropometric, biochemical, and immunologic parameters. Outcome measures included in-hospital mortality and morbidity, and use of health care resources. In-hospital mortality was 39% (120 of 309); renal replacement therapies (hemodialysis or continuous hemofiltration) were performed in 67% of patients (206 of 309); APACHE II score was 23.1+/-8.2 (range, 10 to 52). Severe malnutrition by SGA was found in 42% of patients with ARF; anthropometric, biochemical, and immunologic nutritional indexes were significantly reduced in this group compared with patients with normal nutritional status. Severely malnourished patients, as compared to patients with normal nutritional status, had significantly increased morbidity for sepsis (odds ratio [OR] 2.88; 95% confidence interval [CI], 1.53 to 5.42, P < 0.001), septic shock (OR 4.05; 95% CI, 1.46 to 11.28, P < 0.01), hemorrhage (OR 2.98; 95% CI, 1.45 to 6.13, P < 0.01), intestinal occlusion (OR 5.57; 95% CI, 1.57 to 19.74, P < 0.01), cardiac dysrhythmia (OR 2.29; 95% CI, 1.36 to 3.85, P < 0.01), cardiogenic shock (OR 4.39; 95% CI, 1.83 to 10.55, P < .001), and acute respiratory failure with mechanical ventilation need (OR 3.35; 95% CI, 3.35 to 8.74, P < 0.05). Hospital length of stay was significantly increased (P < 0.01), and the presence of severe malnutrition was associated with a significant increase of in-hospital mortality (OR 7.21; 95% CI, 4.08 to 12.73, P < 0.001). Preexisting malnutrition was a statistically significant, independent predictor of in-hospital mortality at multivariable logistic regression analysis both with comorbidities (OR 2.02; 95% CI, 1.50 to 2.71, P < 0.001), and with comorbidities and complications (OR 2.12; 95% CI, 1.61 to 2.89, P < 0.001). Malnutrition is highly prevalent among ARF patients and increases the likelihood of in-hospital death, complications, and use of health care resources.

Associates of mortality among peritoneal dialysis patients with special reference to peritoneal transport rates and solute clearance

The current report describes the distributions of selected demographic and biochemical parameters, clearance, and other transport values among patients undergoing peritoneal dialysis (PD) and evaluates the associates of mortality using those values, with and without clearance and peritoneal equilibration test (PET) data. All patients receiving PD on January 1, 1994 were selected (n = 2,686). Patients who switched to another form of dialysis during the study period were removed from the study at the time of therapy change. Working files were constructed from the clinical database to include demographic, laboratory, and outcome data. Laboratory data were available in only 1,603 patients and were used to evaluate the biochemical associates of mortality after merging the biochemical, demographic, and outcome data. Patients with clearance data or PET studies underwent a second analysis to assess the effects of peritoneal and renal clearance on survival. The analysis of demographic and laboratory data confirmed the importance of age and serum albumin concentration as predictors of death. Residual renal function (RRF) was strongly correlated with survival, but peritoneal clearance was not. Several possible explanations for the lack of correlation between peritoneal clearance and survival are discussed. The data suggest that RRF and peritoneal clearance may be separate and not equivalent quantities. Substantial work is required to confirm or refute these findings, because the information is essential to establish the adequate dose of PD in patients with various degrees of RRF.

Association of dialyzer reuse with hospitalization and survival rates among U.S. hemodialysis patients: do comorbidities matter?

The objective of this study was to determine whether the associations between reuse of hemodialyzers and higher rates of death and hospitalization persist after adjustment for comorbidity. This was a nonconcurrent cohort study of survival and hospitalization rates among 1491 U.S. chronic hemodialysis patients beginning treatment in 1986 and 1987. The impact of dialyzer reuse was compared across three survival models: an unadjusted model, a "base" model adjusted only for demographics and renal diagnosis, and an "augmented" model additionally adjusted for comorbidities. We found that reuse of dialyzers was associated with a similarly higher rate of death in analyses unadjusted for confounders (relative risk [RR] 1.25, 95% confidence interval [CI] 0.97-1.61), adjusted for demographics and renal diagnosis (RR 1.16, 95% CI 0.96-1.41), and analyses additionally adjusted for comorbidities (RR = 1.25, CI, 1.03, 1.52). Reusing dialyzers was also associated with a greater rate of hospitalization that was stable regardless of adjustment procedures. We conclude that higher rates of death and hospitalization associated with dialyzer reuse persist regardless of adjustment for demographic characteristics or baseline comorbidities. These findings amplify concerns that there exists elevated morbidity among hemodialysis patients treated in facilities that reuse hemodialyzers. Although the association we observed was not confounded by comorbidity, a cause-and-effect relationship between dialyzer reuse and morbidity could not be proved because of the inability to control for aspects of care other than dialyzer reuse.

Does the survival advantage of nonwhite dialysis patients persist after case mix adjustment?

PURPOSE

Nonwhite dialysis patients survive longer than white patients; however, their clinical characteristics differ. We examined whether case mix differences explain the apparent survival advantage of nonwhite dialysis patients.

SUBJECTS AND METHODS

We performed a prospective cohort study using data from the US Renal Data System Case Mix Severity Study that included 4,797 randomly selected dialysis patients 20 years of age and older who were followed up for up to 6 years. Demographic, comorbidity, laboratory, nutritional, and functional status data were obtained. Multivariable proportional hazards models adjusted for case mix differences between nonwhite and white dialysis patients. Additional analyses examined the effects of differences in transplantation rates, withdrawal from dialysis rates, and treatment modality selection.

RESULTS

Unadjusted survival rates of black, Native American, and Asian or Pacific Islander dialysis patients were similar, and better than that for white dialysis patients. Relative to whites, the unadjusted relative risk (RR) for mortality among nonwhite patients was 0.64 (95% confidence interval [CI]: 0.58 to 0.70). Adjustment for case mix reduced, but did not eliminate, the survival advantage associated with nonwhite race (RR = 0.78, CI: 0.71 to 0.86). Adjustment for differences in transplantation rates (RR = 0.83, CI: 0.75 to 0.91), withdrawal from dialysis rates (RR = 0.81, CI: 0.73 to 0.90), and initial treatment modality (RR = 0.79, CI: 0.71 to 0.87) did not explain the lower mortality among nonwhites.

CONCLUSIONS

A survival advantage for nonwhite dialysis patients persists after case mix adjustment. Future studies should explore additional physiologic and socioeconomic factors that might explain this difference.

Haemodialysis

This paper charts the development of haemodialysis, the cornerstone of renal replacement therapy (RRT). It has enabled patients with end-stage renal failure to survive for years, in many cases with a surprisingly good quality of life. Through technological advances, RRT can be offered to patients who are older and more frail. Many have intercurrent comorbid illness. Such patients can have good quality of life, but their survival is shorter since they are likely to succumb early to comorbid illnesses. The challenge to nephrologists is to provide treatment based on exacting standards for all those patients who can benefit, yet to maintain cost-effectiveness. There is increasing recognition that, however good the technology underpinning dialysis, what justifies the cost and commitment that dialysis entails is the provision for the patient of a satisfactory quality of life.

Current and future modalities for functional renal replacement

Approximately 310,000 Americans suffer from end-stage renal disease, with more than 70,000 new cases reported each year. Advances in immunosuppressive therapy for transplanted patients, in addition to the refined care of patients who are dependent on dialysis, have led to an improved survival for patients with renal failure. Structural, molecular, and pharmacologic developments continue to enhance the efficacy and safety of dialysis in the future. In addition, progressive improvements in the past 2 decades in organ transplantation, a greater insight into the immunobiology of graft rejection, and better surgical and medical management have resulted in improved outcomes. Although renal xenotransplantation is still in its early stages of development, additional research is leading this technology forward. Recent successes in harvesting and expanding renal cells in vitro and the development of biologically active synthetic materials allow for the creation of three-dimensional functioning renal units, which, in the future, may be applied ex vivo or in vivo for partial or full replacement of kidney function.

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.

Mortality in end-stage renal disease: a reassessment of differences between patients treated with hemodialysis and peritoneal dialysis

Recent registry studies comparing mortality between peritoneal dialysis (PD) and hemodialysis (HD) patients show conflicting results. The purpose of this study is to determine whether previously published results showing higher mortality for patients treated with PD versus HD in the United States continue to hold true over the period 1987-1993. National mortality rates for PD and HD were extracted from the U.S. Renal Data System (USRDS) annual reports for the cohort periods: 1987-1989, 1988-1990, 1989-1991, 1990-1992, and 1991-1993. Using Poisson regression, death rates per 100 patient years were compared between PD and HD for each cohort period controlling for age, gender, race, and cause of end-stage renal disease (diabetes versus nondiabetes). When incident patients and patients with a prior transplant were included in the analysis, starting with the 1989-1991 cohort, we found little or no difference in the relative risk (RR PD:HD) of death between PD and HD (1987-1989: RR = 1.17, P < 0.001; 1988-1990: RR = 1.12, P < 0.001; 1989-1991: RR = 1.06, P = NS; 1990-1992: RR = 1.06, P = NS; 1991-1993: RR = 1.08, P = 0.043). After a test for goodness-of-fit, separate analyses for diabetic patients and nondiabetic patients were done to examine unexplained variation in death rates. For nondiabetic patients, there was less than a 1% difference in the adjusted 1-yr survival between PD and HD from 1989-1993 (1989-1991: RR = 1.05, P = NS; 1990-1992: RR = 1.04, P = NS; 1991-1993: RR = 1.07, P < 0.01). Among diabetic patients, the PD:HD death rate ratio varied significantly according to gender and age. For the average male diabetic patient, there was little or no difference in risk between PD and HD from 1989-1993 (1989-1991: RR = 1.02, P = NS; 1990-1992: RR = 1.05, P = NS; 1991-1993: RR = 1.08, P < 0.01). For diabetic patients under the age of 50, those treated with PD had a significantly lower risk of death than those treated with HD (1989-1993: 0.84 < or = RR < or = 0.89, P < 0.005). Over the same period, female diabetic patients treated with PD had a higher risk, on average, than HD (1.18 < or = RR < or = 1.19, P < 0.001) as did diabetic patients over the age 50 (1.28 < or = RR < or = 1.30, P < 0.001). Unlike previously published results that were restricted to prevalent-only patients, this national study of both prevalent and incident patients found little or no difference in overall mortality between PD and HD. The recent trends in mortality likely reflect the inclusion of incident patients, but they may also reflect changes in case-mix differences and/or improved PD practice. Additional incident-based studies that allow for additional case-mix adjustments are needed to better compare outcomes between HD and PD.

Inflammation enhances cardiovascular risk and mortality in hemodialysis patients

BACKGROUND

Atherosclerosis, a major problem in patients on chronic hemodialysis, has been characterized as an inflammatory disease. C-reactive protein (CRP), the prototypical acute phase protein in humans, is a predictor of cardiovascular mortality in the general population. We hypothesize that several of the classic, as well as nontraditional, cardiovascular risk factors may respond to acute phase reactions. An activated acute phase response may influence or predict cardiovascular risk.

METHODS

In 280 stable hemodialysis patients, serum lipids, apolipoproteins (apo) A-I and B, lipoprotein(a) [Lp(a)], fibrinogen, and serum albumin (Salb) were determined in relation to CRP and serum amyloid A (SAA), two sensitive markers of an acute phase response. Mortality was monitored prospectively over a two year period.

RESULTS

Serum CRP and SAA were found to be elevated (more than 8 and more than 10 mg/liter, respectively) in 46% and 47% of the patients in the absence of clinically apparent infection. Patients with elevated CRP or SAA had significantly higher serum levels of Lp(a), higher plasma fibrinogen, and lower serum levels of high-density lipoprotein cholesterol, apo A-I, and Salb than patients with normal CRP or SAA. The rise in Lp(a) concentration was restricted to patients exhibiting high molecular weight apo(a) isoforms. During follow-up, 72 patients (25.7%) had died, mostly due to cardiovascular events (58%). Overall mortality and cardiovascular mortality were significantly higher in patients with elevated CRP (31% vs. 16%, P < 0.0001, and 23% vs. 5%, P < 0.0001, respectively) or SAA (29% vs. 19%, P = 0.004, and 20 vs. 10%, P = 0.008, respectively) and were also higher in patients with Salb of lower than 40 g/liter (44% vs. 14%, P < 0.0001, and 34% vs. 6%, P < 0.0001, respectively). Univariate Cox regression analysis demonstrated that age, diabetes, pre-existing cardiovascular disease, body mass index, CRP, SAA, Salb, fibrinogen, apo A-I, and Lp(a) were significantly associated with the risk of all-cause and cardiovascular mortality. During multivariate regression analysis, SAA, fibrinogen, apo A-I, and Lp(a) lost their predictive values, but age and CRP remained powerful independent predictors of both overall death and cardiovascular death.

CONCLUSION

These results suggest that a considerable number of hemodialysis patients exhibit an activated acute phase response, which is closely related to high levels of atherogenic vascular risk factors and cardiovascular death. The mechanisms of activated acute phase reaction in patients on chronic hemodialysis remain to be identified. A successful treatment of the inflammatory condition may improve long-term survival in these patients.

Nutritional status: a continuous quality improvement approach

Intradialytic parenteral nutrition (IDPN) has been used as nutritional repletion in severely malnourished patients with end-stage renal disease (ESRD). This study presents a retrospective look at hemodialysis patients with malnutrition who were followed-up in the process of continuous quality improvement (CQI). The costs of intravenous supplies, hospitalizations, and morbidity are reviewed. The application of continuous quality improvement was used to identify and follow-up malnourished patients. There were significant decreases in number of hospitalizations and days in the hospital.

Blood Urea Nitrogen Stability: A Feasibility Study for Home Hemodialysis Adequacy Testing Through Mail

Urea kinetic modeling measures the delivered dose of hemodialysis and is used to monitor dialysis adequacy. Obtaining samples for adequacy calculations is a challenge for home hemodialysis (HHD) patients. Ideally, the urea reduction ratio (URR) should be measured at a typical dialysis session; therefore, for HHD patients test specimens should be drawn at home and transferred to a clinical laboratory. Would blood urea nitrogen (BUN) remain stable if samples were mailed to the laboratory? To answer this question, BUN was measured in pre- and postdialysis samples from 20 patients over 8 days of laboratory storage. While BUN values varied among the patient population, neither pre- nor postdialysis values showed any significant variation during the 8-day storage time. These results suggest that BUN values are sufficiently stable for specimens to be drawn at home and mailed to a testing laboratory.

The cost of implementing the Dialysis Outcomes Quality Initiative Clinical Practice Guidelines

For a clinical practice guideline to be accepted by the end-user, the system of reimbursement for the targeted service must be favorable. The National Kidney Foundation-Dialysis Outcomes Quality Initiative (NKF-DOQI) Guideline recommendations were developed without primary concern for the costs of their execution. Arguably, an unfavorable financial environment and excessive mercantile behavior by providers and payers would offer a considerable hindrance to their implementation. Toward addressing these concerns, three leaders in the development of the DOQI Guidelines for the Treatment of Anemia of Chronic Renal Failure, Hemodialysis Adequacy, and Vascular Access, have evaluated the hypothesis that implementing the recommendations of the DOQI Guidelines will increase the treatment costs for dialysis providers but will effect savings in the entire end-stage renal disease (ESRD) program. Their analyses suggest that under the current reimbursement system, this assumption may be true. However, restructured global reimbursement in the ESRD program will permit financial incentives for dialysis providers and the payer to coincide.

Recommended criteria for initiating and discontinuing intradialytic parenteral nutrition therapy

The indications for intradialytic parenteral nutrition (IDPN) in patients with end-stage renal disease remain controversial. Medicare has taken a position to severely limit the use of this form of nutritional therapy. Are there patients who do not meet the government criteria, yet would benefit from this therapy? Studies are required to answer this question, but they may be years away. In the interim, identification of appropriate patients, development of appropriate criteria for initiating and discontinuing therapy, as well as a proper reimbursement process should be considered for the treatment of severe malnutrition in this population of patients. This article discusses these topics and outlines a different approach to the use of IDPN.

Hemodialysis adequacy in Network 5: disparity between states and the role of center effects

The purpose of this study was to determine whether an observed difference in hemodialysis adequacy between states in Network 5 was due to variations in patient characteristics and to what extent dialysis center effects played a role in the observed disparity between states. This was a retrospective observational study of 6,969 patients dialyzed at centers in Maryland and Virginia. There were 3,919 patients on hemodialysis at 89 facilities in Virginia and 3,050 subjects dialyzed at 65 centers in Maryland. The mean urea reduction ratio (URR) was higher in Virginia compared with Maryland (68.2 +/- 0.1% v 66.0 +/- 0.2%, P < 0.0001, respectively), and there continued to be a mean difference in URR of 1.8% between VA and MD (P < 0.0001) after adjusting for several covariates. The differences in URR between states varied depending on facility proprietary status, size as measured by number of stations, and relationship to hospital (free-standing or hospital-based). Furthermore, the center where a patient dialyzed, when treated as a fixed effect, accounted for 15% of the variance in URR. The mean difference of 1.8% in URR between states persisted in a mixed-effects model that included all covariates along with adjusting for dialysis centers as a random effect. The disparity in dialysis adequacy between states in Network 5 could not be accounted for by demographic characteristics, case mix factors, or a large center effect observed in the region. Therefore, we conclude that underlying national reports on dialysis adequacy are heterogeneous results related to differences across regions such as states within a given Network. This difference between states is not explained by the strong center effect found on adequacy in this population of hemodialysis patients.

Practical guide to measuring adequacy of dialysis

Measurement of adequacy of small solute clearance on hemodialysis (HD) and peritoneal dialysis (PD) is important. In HD, formal urea kinetic modelling (UKM) is recommended because it is theoretically more accurate than the urea reduction ratio (URR) and because it allows prospective selection of an adequate prescription. However, the URR is simpler and has an important role to play. Precise attention to the methodology of sampling the post-HD blood urea is important. In PD, both Kt/V and creatinine clearance should be measured, and the main concerns relate to logistic problems in collection and processing of dialysate samples. In both HD and PD, a well-defined standardized methodology for measuring adequacy indices should be in place in each dialysis unit.

Therapeutic approaches to malnutrition in chronic dialysis patients: the different modalities of nutritional support

Protein-energy malnutrition (PEM) is a common complication in maintenance hemodialysis and chronic peritoneal dialysis patients and is a powerful predictor of morbidity and mortality. Although this association does not prove that malnutrition is a cause of this increased morbidity and mortality, it is consistent with this possibility. There are a number of modalities of nutritional support for the prevention or treatment of PEM in maintenance dialysis patients. Routine methods include preventing PEM before the onset of maintenance dialysis therapy, dietary counseling, maintenance of an adequate dose of dialysis, avoidance of acidemia, and aggressive treatment of superimposed catabolic illness. Specific treatments of chronic dialysis patients who have persistently inadequate nutritional intake include food supplements, enteral tube feeding, intradialytic parenteral nutrition, and total parenteral nutrition. More experimental forms of nutritional therapy include dialytic nutrition (eg, using peritoneal dialysate or hemodialysate that contains amino acids), appetite stimulants (eg, megestrol acetate), or growth factors (eg, anabolic steroids, recombinant human growth hormone, or insulin-like growth factor-I).

The effect of blood draw methodology on selected nutritional parameters in chronic renal failure

The reliability and validity of any clinical laboratory test is directly affected by the integrity of the blood specimen obtained for analysis. Renal failure patients undergo a high number of laboratory tests, primarily to monitor the quality of care. Subsequent tests to confirm laboratory abnormalities are costly and place the patient at unnecessary risk for additional blood loss. Three of the four Health Care Financing Administration core clinical outcome indicators have nutritional implications and use laboratory values as part of review criteria: adequacy of dialysis, albumin, and anemia. National Kidney Foundation-Dialysis Outcomes Quality Initiative (DOQI) Clinical Practice Guidelines have recommended standardized predialysis and postdialysis blood draw procedures to increase accuracy for adequacy of dialysis. The National Committee on Clinical Laboratory Standards publishes peer-reviewed guidelines for venipuncture. Together, the adoption of these standards would minimize preanalytical variation and improve the data used to monitor the quality of care in renal patients.

Morbidity and mortality on maintenance haemodialysis

Despite the many technical advances in medical care and dialysis delivery, mortality and morbidity remain high in end-stage renal disease (ESRD) patients. A number of factors seem to contribute. Cardiovascular diseases are the leading cause of death: volume overload, anaemia, hypertension, arteriovenous fistula, uraemia-related myocardial cell injury all contribute to the development of ischaemic heart disease and congestive heart failure. The underlying disease is determinant for prognosis, with diabetics displaying an excess cardiovascular mortality. Elderly are also more likely to experience intercurrent medical conditions, vascular disease and diabetes, thus increasing the risk of death. Protein-energy malnutrition and wasting also contribute to the higher mortality in renal replacement therapy. Although nowadays high-risk patients are dialysed too, the rate of acceptance of ESRD patients still varies widely in different countries, possibly because of hidden selection criteria. The patients in the registries with a higher acceptance rate are more likely to be affected by co-morbid conditions and greater disease severity; the assessment of these co-morbid conditions is extremely important when comparing outcomes in different haemodialysis populations. Dialysis adequacy, obtained by means of longer duration of the treatment, is also of paramount importance; it allows minimizing the clinical effects of ultrafiltration and ensure that correct dry weight is reached. This means decreasing the incidence of intradialytic hypotensive episodes, but also improving blood pressure control, a strong predictor of survival. Family and social support, together with adequate medical care, greatly affect the quality of life of patients and can improve compliance to dialysis, diet and drugs and therefore survival.

Blood pressure, left ventricular hypertrophy and long-term prognosis in hemodialysis patients

Cardiovascular events are the main cause of death in patients with chronic renal failure who are treated with hemodialysis. Hypertension is frequent among dialysis patients and may be a major cause of mortality, although epidemiological studies are controversial in this regard. This disparity in results may be the consequence of an inadequate definition of hypertension in dialysis patients as well as the interaction with hypertension with other risk factors such as malnutrition or left ventricular hypertrophy (LVH), which are strong predictors of death. Although the goal of blood pressure in dialysis has not been established yet, it seems that predialysis blood pressure levels lower than 150/90 mm Hg must be achieved for patients to avoid complications. LVH is very frequent among dialysis patients and starts early in the progression of chronic renal failure. Hypertension is the main cause for its development, but other potentially reversible factors such as anemia, volume overload, secondary hyperparathyroidism, dose of dialysis or malnutrition may also be implicated. Hence, an adequate management of patients on hemodialysis must include the strict control of blood pressure, preferably with angiotensin converting enzyme (ACE) inhibitors, together with those early measures in order to avoid the development of the other causes of LVH or to treat them when they already exist.

Improved biochemical variables, nutrient intake, and hormonal factors in slow nocturnal hemodialysis: a pilot study

OBJECTIVE

To determine whether slow nocturnal hemodialysis (SNHD) can be safely performed in patients with end-stage renal disease to improve the biochemical and clinical outcome.

MATERIAL AND METHODS

We conducted an 8-week pilot study in nondiabetic adult patients, who underwent dialysis 6 nights per week for 8 hours each night. A dialysate flow rate of 300 mL/min and a blood flow rate of 250 mL/min, through an internal jugular dual-lumen venous catheter, were used. The equipment used was a COBE Centry System 3 dialysis machine and Fresenius F-80 (1.8 m2) or Baxter CT 190 (1.9 m2) dialyzers. Five patients were enrolled in the study.

RESULTS

Two patients did not complete the study because of catheter-related infections--one at day 7 and one after 4 weeks of SNHD. All patients had improved blood pressure control, and no intradialytic adverse events occurred. Dietary intake improved, urea and creatinine levels significantly decreased, and weekly delivery of dialysate increased on SNHD. Potassium, chloride, beta 2-microglobulin, phosphorus, calcium, and high-density lipoprotein cholesterol all improved on SNHD. Serum testosterone increased in the three men on SNHD, but parathyroid hormone, luteinizing hormone, and follicle-stimulating hormone remained unchanged. Erythropoietin levels increased on SNHD, despite no change in exogenous erythropoietin doses in three patients and discontinuation of administration of erythropoietin in one. The following biochemical factors did not change significantly: serum sodium, bicarbonate, vitamin B12, folate, alkaline phosphatase, total cholesterol, triglycerides, and albumin.

CONCLUSION

Higher doses of hemodialysis benefit nutrition, improve biochemical variables, and may improve many hormonal systems.

C-reactive protein as an outcome predictor for maintenance hemodialysis patients

BACKGROUND

The possible association between inflammatory processes and other outcome measures in ESRD patients led us to measure the blood C-reactive protein (CRP) concentration in a large sample of hemodialysis patients, and to evaluate its statistical relationship with other common laboratory measures and patient survival. This was performed in a prospective, observational analysis with mortality as the principal outcome measure.

METHODS

One thousand fifty-four routine blood samples, collected from as many patients during June and July 1995 (one sample per patient), were randomly selected for measurement of CRP, prealbumin, and other routine laboratory measures. Six months after the initial blood tests, patient survival was determined: Logistic regression analysis was the primary statistical tool used to evaluate laboratory associations with odds of death. Bivariate regression and correlation analyses were performed using all available data.

RESULTS

The distribution of CRP values was skewed; approximately 35% of the values exceeded the upper limit of the laboratory's reference range. Serum albumin and prealbumin concentrations both correlated with the serum creatinine concentration (r = 0.378 and r = 0.347, respectively; P's < 0.001), and were inversely associated with the CRP (r = -0.254 and r = -0.354, respectively; P's < 0.001). CRP was also inversely associated with blood hemoglobin concentrations (r = -0.235; P < 0.001). Using multiple regression analysis to further explore these relationships, the serum creatinine concentration was inversely associated with CRP (r = -0.140; P < 0.001). However, after adjustment for the linkage of the serum creatinine with the serum albumin concentration (r = -0.378; P < 0.001), no relationship with creatinine was observed. Before and after adjustment for serum albumin and prealbumin concentration, the ferritin concentration correlated directly with CRP (r = 0.148; P < 0.001). Ferritin was inversely and highly correlated with total iron binding capacity (r = -0.516; P < 0.001). Independent associations of hemoglobin with albumin (t = 7.16; P < 0.001), prealbumin (t = 2.39; P = 0.017), and CRP (t = -4.27; P < 0.001) were observed. Also, the dose of erythropoietin was directly associated with the CRP concentration, before (r = 0.081, P = 0.009) and after (t = 2.03, P = 0.042) adjustment for the serum albumin and iron concentrations. CRP correlated directly with neutrophil (r = 0.318; P < 0.001) and platelet counts (r = 0.180; P < 0.001), but was weakly and inversely correlated with the lymphocyte count (r = -0.071; P = 0.04). A logistic regression analysis performed using the laboratory variables revealed a strong, independent, and inverse relationships between the serum albumin and creatinine concentrations, total lymphocyte count, and the odds risk of death. In this model, no significant relationship was observed between the odds risk of death and CRP.

CONCLUSIONS

The data presented herein suggest that: (1) strong predictable associations exist among laboratory proxies for malnutrition, anemia, and the acute phase reaction, and (2) the pathobiology implied by these laboratory abnormalities influence patients' mortal risk primarily through depletion of vital body proteins, not inflammation.

Validation of serum transthyretin (prealbumin) as a nutritional parameter in hemodialysis patients

OBJECTIVE

To evaluate the use of serum transthyretin (TTR) as a valid indicator of nutritional status in the hemodialysis patient and to validate the correlation of low-serum (TTR) levels with established nutrition assessment parameters.

DESIGN

Prospective, cohort, correlation analysis.

SETTING

Free-standing outpatient dialysis center.

PATIENTS

Fifty-one stable, chronic hemodialysis patients meeting the following selection criteria: (1) received thrice weekly hemodialysis treatments for greater than 3 months, (2) absence of impaired hepatic function, (3) absence of chronic infection, inflammatory syndromes, or infections in the 3 months before the study, (4) not taking corticosteroids, and (5) willing to participate in the study as evidenced by signing of an informed consent.

INTERVENTION

Serum TTR, albumin, blood urea nitrogen, creatinine, cholesterol, postdialysis weight and body mass index were measured monthly for 6 consecutive months. Normalized protein catabolic rate and KT/V were measured monthly for 3 consecutive months.

MAIN OUTCOME MEASURES

Nutrition and biochemical indices.

RESULTS

The overall mean TTR level was 32 mg/dL +/- 7 for the 6-month study period. Thirty-six percent of patients had mean TTR levels less than 30 mg/dL. TTR levels less than 30 mg/dL correlated significantly with urine outputs greater than 240 mL/24 hours, predialysis blood urea nitrogen < 18 mmol/L (<50 mg/dL), and normalized protein catabolic rate less than 0.8 g/kg/d (P < .05). A significant correlation was found between TTR and creatinine, albumin and loss of dry body weight (P < .05). Mean TTR levels less than 30 mg/dL were found in 33% of subjects with mean albumin levels greater than 35 g/L (>3.5 g/dL) and in 19% with mean albumin levels greater than 40 g/L (>4.0 g/dL). TTR levels were consistently lower in diabetics for all 6 months (statistically significant in 2 out of 6 months).

CONCLUSION

Measuring serial serum TTR levels in hemodialysis patients is a reliable method for identifying patients in need of nutrition intervention.

Immunologic function and survival in hemodialysis patients

BACKGROUND

Although the medical determinants of mortality in patients with end-stage renal disease (ESRD) treated with hemodialysis (HD) are well appreciated, the contribution of immunologic parameters to survival in such patients is unclear, especially when variations in age, medical comorbidity and nutrition are controlled. In addition, although dysregulation of cytokine metabolism has been appreciated in patients with ESRD, the association of these parameters with outcomes has not been established. Recently, the type of dialyzer used in patients' treatment has been associated with survival, but the mechanisms underlying these findings, including their immune effects, have not been established. We conducted a prospective, cross-sectional, observational multicenter study of urban HD patients to determine the contribution of immunological factors to patient survival. We hypothesized increased proinflammatory cytokines would be associated with increased mortality, and that improved immune function would be associated with survival.

METHODS

Patients were assessed using demographic and anthropometric indices, Kt/V, protein catabolic rate (PCR) and immunologic variables including circulating cytokine [interleukin (IL)-1, IL-2, IL-4, IL-5, IL-6, IL-12, IL-13 and tumor necrosis factor (TNF)-alpha] levels, total hemolytic complement activity (CH50), and T cell number and function. A severity index, previously demonstrated to be a mortality marker, was used to grade medical comorbidity. A Cox proportional hazards model, controlling for patients' age, severity index, level of serum albumin concentration, dialyzer type and dialysis site was used to asses relative survival risk.

RESULTS

Two hundred and thirty patients entered the study. The mean (+/- SD) age of the population was 54.4 +/- 14.2 years, mean serum albumin concentration was 3.86 +/- 0.47 g/dl, mean PCR was 1.1 +/- 0.28 g/kg/day, and mean Kt/V 1.2 +/- 0.3. Patients' serum albumin concentration was correlated with levels of Kt/V and PCR, and their circulating IL-13 and TNF-alpha levels, but negatively with their circulating IL-2 levels, T-cell number and T-cell antigen recall function. T-cell antigen recall function correlated negatively with PCR, but not Kt/V. There was no correlation of any other immune parameter and medical or demographic factor. Immune parameters, were all highly intercorrelated. Mean level of circulating cytokines in HD patients were in all cases greater than those of a normal control group. There were few differences in medical risk factors or immune parameters between patients treated with different types of dialyzers. After an almost three-year mean follow-up period, increased IL-1, TNF-alpha, IL-6, and IL-13 levels were significantly associated with increased relative mortality risk, while higher levels of IL-2, IL-4, IL-5, IL-12, T-cell number and function, and CH50 were associated with improved survival. The difference in survival between patients treated with unmodified cellulose dialyzers and modified or synthetic dialyzers approached the level of statistical significance, but there were no differences in levels of circulating cytokines between these two groups.

CONCLUSIONS

Higher levels of circulating proinflammatory cytokines are associated with mortality, while immune parameters reflecting improved T-cell function are associated with survival in ESRD patients treated with HD, independent of other medical risk factors. These factors may serve as markers for outcome. The mechanism underlying the relationship of immune function and survival, and the effect of interventions to normalize immune function in HD patients should be studied.

Psychosocial factors, behavioral compliance and survival in urban hemodialysis patients

BACKGROUND

The medical risk factors associated with increased mortality in hemodialysis (HD) patients are well known, but the psychosocial factors that may affect outcome have not been clearly defined. Psychosocial factors could affect mortality through interaction with parents' nutrition or their compliance with the dialysis prescription. We conducted a prospective, longitudinal, multicenter study of urban HD patients to determine the contribution of compliance and psychosocial factors to patient survival.

METHODS

Patients were assessed using indices of social support, patient's assessments of their well-being, including illness effects (IEQ), and satisfaction with life (SWLS), the Beck Depression Inventory (BDI), serum albumin concentration, Kt/V and protein catabolic rate (PCR). Behavioral compliance was measured three ways: percent time actually dialyzed per treatment compared to prescribed time (shortening behavior); percent sessions attended (skipping behavior) and total integrated time compliance (% TCOMP). A severity index, previously demonstrated to be a mortality marker, was used to grade medical comorbidity. The typed of dialyzer the patient was treated with was noted. A Cox proportional hazards model, controlling for age, medical comorbidity, albumin concentration and dialyzer type was used to assess relative mortality risk of variations in psychosocial factors and behavioral compliance.

RESULTS

A total of 295 patients (60.8% of those eligible) agreed to participate. The mean ( +/- SD) age of our population was 54.6 +/- 14.1 year, mean PCR was 1.06 +/- 0.27 g/kg/day, and mean Kt/V 1.2 +/- 0.4, suggesting the patients were well nourished and adequately dialyzed. The patients' mean BDI was 11.4 +/- 8.1 (in the range of mild depression). Patients' SWLS was similar to that of a group of patients without chronic illness. After a 26 month mean follow-up period, higher levels of perceived social support, improved perception of the effects of illness and increased behavioral compliance were significantly associated with decreased relative mortality risk (0.8, 0.77, and 0.79, respectively), controlled for variations in patients' age, severity of illness, serum albumin concentration and dialyzer type. Variations in depression and Kt/V were not predictors of mortality during the observation period.

CONCLUSIONS

Lower levels of social support, decreased behavioral compliance with the dialysis prescription, and increased negative perception of the effects of illness are independently associated with increased mortality in ESRD patients treated with HD. The effects are of the same order of magnitude as medical risk factors. Such effects may be attributable to a relationship between a patients' perception of social support and effects of illness and behavior, with other factors such as the provision of better medical care in patients with larger social networks. The mechanism underlying the relationship of psychosocial factors and compliance and survival, and the effect of interventions to improve perception of illness, and increase social support and compliance with the dialysis prescription in HD patients should be studied.

Distinct HLA class II alleles determine antibody response to vaccination with hepatitis B surface antigen

Major histocompatibility complex (MHC) determinants control antibody production in response to protein antigens. Vaccination with hepatitis B surface antigen (HBsAg) frequently fails in hemodialyzed patients, but the genetic factors that modulate humoral responsiveness are poorly characterized. We studied the distribution of HLA class II alleles in 415 hemodialyzed Caucasian patients who received a full course of HBsAg vaccination, using class II oligotyping after genomic amplification of the DRB1 and DQB1 loci. Phenotype frequencies were compared in 114 non responders (anti-HBs antibodies < or = 10 SI units/liter), 301 responders (anti-HBs antibodies > 10 units/liter) and 471 healthy controls. DRB1*01 (DR1) and DRB1*15 (DR15) frequencies were lower in nonresponders than in responders and controls (DR1, 12.3% vs. 22.9% and 24.8%, respectively; DR15, 14% vs. 22.9% and 25.1%), while DRB1*03 (DR3) and DRB1*14 (DR14) frequencies were higher (DR3, 32.5% vs. 16.6% and 25.3%, respectively; DR14, 9.6% vs. 3% and 6.6%). Overall, 44.5% of DR3 or DR14 patients were nonresponders, compared to 18.1% of DR1 or DR15 patients (P = 0.0001). In conclusion the humoral response to HBsAg vaccine is influenced by class II allelic variants, which differ in their capacity to bind and present peptides to T lymphocytes.

Relationship between serum phosphorus levels and various outcome measures in adult hemodialysis patients

OBJECTIVE

To compare three different mean serum phosphorus ranges on outcomes related to the control and treatment of hyperparathyroidism (HPTH), to nutritional status, and to quality of life (QOL) in adult hemodialysis (HD) patients.

DESIGN

Patients were grouped based on the mean of five monthly phosphorus levels achieved during the study period. Group 1 included patients whose mean phosphorus levels over the period was <6.0 mg/dL (n = 24); group 2 averaged between 6.0 and 6.9 mg/dL (n = 14); and group 3 averaged >7.0 mg/dL (n = 16). Descriptive comparisons were made between phosphorus groups.

PATIENTS

Fifty-four stable, adult HD patients participated voluntarily.

MAIN OUTCOME MEASURES

Intact-parathyroid hormone (iPTH), calcium x phosphorus product (Ca x P), and change in iPTH, albumin (alb), total protein (tpro), weight (wt) and body mass index (BMI), and scores on a QOL survey. Baseline physical and lab characteristics.

RESULTS

No difference was found between phosphorus levels of <6.0 mg/dL and levels of 6.0 to 6.9 mg/dL in iPTH, Ca x P levels allowing safe calcitriol therapy, nor response to calcitriol treatment. Patients with phosphorus levels >7.0 mg/dL had midstudy iPTH greater than phosphorus levels <6.0 mg/dL. Otherwise the three groups did not differ significantly in iPTH levels. Phosphorus levels 6.0 to 6.9 mg/dL was associated with lowest wt and BMI, but alb and tpro did not differ between the phosphorus groups. Phosphorus levels of >7.0 was associated with highest creatinine levels and youngest age. Subjects in the phosphorus levels of <6.0 mg/dL gp were more likely than the 6.0 to 6.9 mg/dL gp to describe their diet as sufficient and, at baseline, were more likely to relate diet to QOL.

CONCLUSION

Comparison of three levels of serum phosphorus on indicators of outcome in the control and treatment of secondary hyperparathyroidism showed no significant difference in outcome between phosphorus levels of <6.0 mg/dL and phosphorus levels 6.0 to 6.9 mg/dL. However, the data suggests that phosphorus levels of >7.0 mg/dL may relate to significantly higher iPTH and unacceptable Ca x P levels. There were no differences between the groups, suggesting less favorable outcome at any of the three phosphorus levels regarding nutritional status or QOL in this small group of stable, adult HD patients.

The Kidney Outcomes Prediction and Evaluation (KOPE) study: a prospective cohort investigation of patients undergoing hemodialysis. Study design and baseline characteristics

PURPOSE

The purpose of the Kidney Outcomes Prediction and Evaluation (KOPE) study, was to more fully characterize the end-stage renal disease (ESRD) population with respect to social, psychological, and clinical characteristics, and to prospectively study the biomedical, social, and psychological factors that influence a range of ESRD outcomes in a large observational study of black and white patients on hemodialysis. This paper focuses on the KOPE study design as well as characteristics of patients at baseline.

METHODS

KOPE was a prospective cohort investigation of patients treated at four dialysis centers in Forsyth County, North Carolina. Participants were interviewed at the dialysis centers, semi-annually over a 3 1/2 year period. Prevalent cases who were being treated with hemodialysis at the initiation of the study were enrolled into KOPE. Incident cases were subsequently enrolled as they presented to the participating units for hemodialysis. A total of 304 prevalent and 162 incident cases were enrolled into the study. The baseline health and sociodemographic characteristics of KOPE participants reported in this paper were obtained from medical records and Southeast Kidney Council data. Laboratory values taken within a 30-day interval around the baseline interview are also reported.

RESULTS

KOPE participants differ from national statistics on race, age, and gender. Differences between KOPE participants and patients living in the region, but who did not participate in the study, can be explained by our recruitment criteria.

CONCLUSIONS

KOPE will enable the characterization of the ESRD population, identification of factors related to poor outcomes, and identification of opportunities for interventions to prevent death and morbidity.

Total iron-binding capacity-estimated transferrin correlates with the nutritional subjective global assessment in hemodialysis patients

We examined the value of transferrin concentrations in estimating nutritional status as determined by the subjective global assessment (SGA) score. Fifty-nine hemodialysis patients (37 men and 22 women, aged 59+/-16 years, dialyzed for 3.6+/-3.9 years) were selected by predetermined criteria. All received erythropoietin (EPO) and oral iron therapy. SGA evaluation was conducted twice by both a dietitian and a physician. Serum iron, total iron-binding capacity (TIBC; which is linearly correlated with transferrin), transferrin saturation ratio, ferritin, albumin, total protein, and cholesterol were measured. Twenty-seven (46%) patients were well nourished (group A), 20 (34%) were moderately nourished (group B), and 12 (20%) were poorly nourished (group C) according to the SGA. TIBC values were 276+/-47 mg/dL, 217+/-54 mg/dL, and 176+/-41 mg/dL, respectively (P < 0.00001), and thus directly correlated with the state of nutrition. The relationship between TIBC and nutritional status was independent of age and number of years on hemodialysis. Serum ferritin values were 104+/-93 ng/mL, 161+/-154 ng/mL, and 363+/-305 ng/mL, respectively (P < 0.0003), and thus inversely correlated with the state of nutrition. Transferrin saturation ratios were slightly higher in the severely malnourished patients. The number of years on dialysis were a determinant of nutritional status. These values were 2.4+/-2.4 years for group A, 3.9+/-4.0 years for group B, and 5.7+/-3.9 years for group C (P < 0.05). The average age of the poorly nourished patients was 10 years older than the well-nourished patients. Serum iron values were lower but transferrin saturation ratios were higher in the severely malnourished patients. The required EPO doses were higher in the poorly nourished patients. We suggest that transferrin values are superior to other laboratory tests in assessing nutrition and will supplement SGA criteria. Serum ferritin may be useful as a predictor of illness. Older patients who have been on dialysis longer warrant special concern. Malnutrition may be an indicator of EPO resistance in dialysis patients. Finally, since a decreased TIBC level in poorly nourished patients may erroneously increase the transferrin saturation ratio, our findings may have implications in making the diagnosis and treatment of anemia and iron deficiency in malnourished dialysis patients.

Using the hemodialysis prognostic nutrition index and urea reduction ratio to predict morbidity and mortality: a pilot study of the 1995 council on renal nutrition national research question

OBJECTIVE

To validate the use of the hemodialysis prognostic nutrition index (HPNI) in an alternate hemodialysis population and to determine if use of urea reduction ratio would improve use in outcome prediction for morbidity and mortality.

DESIGN

Prospective random cohort.

SETTING

Hospital based non-for-profit outpatient dialysis unit.

PATIENTS

Forty chronic hemodialysis patients, 50% men, 50% black, 16% diabetic, 67.2 mean months on hemodialysis, mean age 54.5 years.

INTERVENTIONS

None; observational; tracking of routinely collected demographic, biochemical, and clinical data.

MAIN OUTCOME MEASURES

Number of times and days hospitalized, mortality

RESULTS

Plotting of HPNI against urea reduction ratio produced risk quadrants for hospitalization that were more predictive than HPNI alone.

CONCLUSION

Application continues as a multicenter collaborative Council on Renal Nutrition National Research Question.

The hemodialysis pilot study: nutrition program and participant characteristics at baseline. The HEMO Study Group

OBJECTIVE

Describe the nutrition program (assessments and interventions) and the participants' baseline nutritional characteristics in the Hemodialysis Pilot Study.

DESIGN

Cross sectional survey in which hemodialysis patients were examined during 10 weeks of baseline (BL), before randomization study interventions (dose and flux).

SETTING

Four hemodialysis centers (eight dialysis units in total).

PATIENTS

Twenty-nine male (mean age, 63 years; range, 34 to 75) and 20 female (mean age, 61 years; range, 29 to 73) hemodialysis patients.

INTERVENTIONS

None during BL.

MAIN OUTCOME MEASURES

Feasibility of implementing the proposed nutrition program before conducting the full-scale trial, and description of baseline characteristics related to nutrition.

RESULTS

A nutrition program was developed to assess nutritional status during BL and follow-up periods and to intervene in patients with weight loss or decreasing serum albumin. Methods for collecting biochemical, dietary and anthropometric data were implemented at four clinical centers. At baseline, mean protein intake estimated by single pool normalized protein catabolic rate was 0.95 +/- 0.21 gm/kg adjusted body weight (ABW) (n = 42) and by diet record assisted recalls (n = 47) 0.94 +/- 0.36 gm/kg ABW/d, respectively. Mean energy intake was 22.8 +/- 8 kcal/kg ABW/day (n = 39). Mean serum albumin concentration using the bromcresol green method was 3.8 +/- 0.4 gm/dL (n = 40). Mean body mass index was within the normal limits of 19-27 kg/m2. Mean skinfold thicknesses in females, but not males, were shifted toward the lower end of usual distributions for healthy individuals.

CONCLUSIONS

The goal of designing, developing, and implementing the diet and nutrition component, and related data collection for the HEMO pilot study was accomplished at four separate clinical centers. Baseline mean protein and energy intake were low, suggesting that continuing dietary surveillance is needed. The ongoing full-scale HEMO study will provide the first prospective analysis of dietary intake, nutritional status, and outcome in maintenance hemodialysis patients as a function of dialysis dose and membrane flux.

Effects of a supplemented very low protein diet in predialysis patients on the serum albumin level, proteinuria, and subsequent survival on dialysis

A very low protein diet (0.3 g/kg ideal body weight) supplemented with essential amino acids (or ketoanalogues) is seldom employed at present in chronic renal failure for fear of inducing protein deficiency, especially in patients who also have the nephrotic syndrome. Nevertheless, we have used this dietary regimen in predialysis patients for a number of years. We have shown that when these patients reach the end stage, they rarely exhibit hypoalbuminemia, in contrast to the reported 25-50% hypoalbuminemia at the onset of dialysis nationwide. Furthermore, their survival for the first 2 years on dialysis is much improved, in comparison with the national experience, adjusted for age, sex, and cause of renal disease. When nephrotic patients are given this regimen, they exhibit some improvement in parameters of the nephrotic state, but nevertheless progress to dialysis, provided their initial glomerular filtration rate (GFR) is < 30 ml/min. However, if their initial GFR is > 30 ml/min, they may show gradual but complete remission of the nephrotic syndrome, even when the underlying disease is diabetic nephropathy or focal segmental glomerulosclerosis. We conclude that this dietary regimen is not only safe in patients with renal failure, with or without the nephrotic syndrome, but may be of substantial benefit. The mechanism remains to be explained.