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N. L. Lew

Bio: N. L. Lew is an academic researcher. The author has contributed to research in topics: Hemodialysis & Urea reduction ratio. The author has an hindex of 3, co-authored 3 publications receiving 1688 citations.

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Journal ArticleDOI
TL;DR: Low urea reduction ratios during dialysis are associated with increased odds ratios for death, and these risks are worsened by inadequate nutrition.
Abstract: Background Among patients with end-stage renal disease who are treated with hemodialysis, solute clearance during dialysis and nutritional adequacy are determinants of mortality. We determined the effects of reductions in blood urea nitrogen concentrations during dialysis and changes in serum albumin concentrations, as an indicator of nutritional status, on mortality in a large group of patients treated with hemodialysis. Methods We analyzed retrospectively the demographic characteristics, mortality rate, duration of hemodialysis, serum albumin concentration, and urea reduction ratio (defined as the percent reduction in blood urea nitrogen concentration during a single dialysis treatment) in 13,473 patients treated from October 1, 1990, through March 31, 1991. The risk of death was determined as a function of the urea reduction ratio and serum albumin concentration. Results As compared with patients with urea reduction ratios of 65 to 69 percent, patients with values below 60 percent had a higher risk of ...

1,357 citations

Journal ArticleDOI
TL;DR: Anemia may be predictive of an increased risk of mortality in some hemodialysis patients and laboratory surrogates of iron stores, nutritional status, and the delivered dose of dialysis are predictive of hemoglobin concentration.
Abstract: Despite the prevalent use of recombinant human erythropoietin (rhEPO), anemia is a frequent finding in hemodialysis patients. The goal of this study was to evaluate the impact of anemia on patient survival and characterize the determinants of hematopoiesis that may be amenable to therapeutic manipulation to enhance rhEPO responsiveness and reduce death risk. Patient characteristics and laboratory data were collected for 21,899 patients receiving hemodialysis three times per week in dialysis centers throughout the United States in 1993. Hemoglobin concentrations (Hb) 110 g/L. Using multiple linear regression, variables of rhEPO administration (rhEPO dose and percentage of treatments that rhEPO was administered), variables of iron status (serum iron, transferrin saturation, and ferritin), variables of nutritional status (serum albumin and creatinine concentration), and the dose of dialysis (urea reduction ratio) were found to be significantly associated with hemoglobin concentration (P 110 g/L are not associated with further improvements in the odds of death. (3) Laboratory surrogates of iron stores, nutritional status, and the delivered dose of dialysis are predictive of hemoglobin concentration. Whether manipulation of the factors that improve anemia will also enhance the survival of patients on hemodialysis is unknown and should be evaluated by prospective, interventional studies.

254 citations

Journal ArticleDOI
TL;DR: It is shown that color flow doppler evaluation, quantifying blood flow in a prosthetic graft, can identify those grafts at risk for failure and preemptory repair of an anatomical abnormality in vascular access grafts with decreased blood flow may decrease patient inconvenience, associated morbidity, and associated costs.
Abstract: Color flow doppler ultrasound examination of the hemodialysis access was conducted in 2,792 hemodialysis patients to evaluate its value in predicting hemodialysis access failure. After baseline assess

129 citations


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Journal ArticleDOI
TL;DR: In patients with chronic kidney disease, early complete correction of anemia does not reduce the risk of cardiovascular events and there was no significant difference in the combined incidence of adverse events between the two groups.
Abstract: BACKGROUND Whether correction of anemia in patients with stage 3 or 4 chronic kidney disease improves cardiovascular outcomes is not established. METHODS We randomly assigned 603 patients with an estimated glomerular filtration rate (GFR) of 15.0 to 35.0 ml per minute per 1.73 m 2 of body-surface area and mild-to-moderate anemia (hemoglobin level, 11.0 to 12.5 g per deciliter) to a target hemoglobin value in the normal range (13.0 to 15.0 g per deciliter, group 1) or the subnormal range (10.5 to 11.5 g per deciliter, group 2). Subcutaneous erythropoietin (epoetin beta) was initiated at randomization (group 1) or only after the hemoglobin level fell below 10.5 g per deciliter (group 2). The primary end point was a composite of eight cardiovascular events; secondary end points included left ventricular mass index, quality-of-life scores, and the progression of chronic kidney disease. RESULTS During the 3-year study, complete correction of anemia did not affect the likelihood of a first cardiovascular event (58 events in group 1 vs. 47 events in group 2; hazard ratio, 0.78; 95% confidence interval, 0.53 to 1.14; P = 0.20). Left ventricular mass index remained stable in both groups. The mean estimated GFR was 24.9 ml per minute in group 1 and 24.2 ml per minute in group 2 at baseline and decreased by 3.6 and 3.1 ml per minute per year, respectively (P = 0.40). Dialysis was required in more patients in group 1 than in group 2 (127 vs. 111, P = 0.03). General health and physical function improved significantly (P = 0.003 and P<0.001, respectively, in group 1, as compared with group 2). There was no significant difference in the combined incidence of adverse events between the two groups, but hypertensive episodes and headaches were more prevalent in group 1. CONCLUSIONS In patients with chronic kidney disease, early complete correction of anemia does not reduce the risk of cardiovascular events. (ClinicalTrials.gov number, NCT00321919.)

1,955 citations

Journal ArticleDOI
TL;DR: Patients undergoing hemodialysis thrice weekly appear to have no major benefit from a higher dialysis dose than that recommended by current U.S. guidelines or from the use of a high-flux membrane.
Abstract: Background The effects of the dose of dialysis and the level of flux of the dialyzer membrane on mortality and morbidity among patients undergoing maintenance hemodialysis are uncertain. Methods We undertook a randomized clinical trial in 1846 patients undergoing thrice-weekly dialysis, using a two-by-two factorial design to assign patients randomly to a standard or high dose of dialysis and to a low-flux or high-flux dialyzer. Results In the standard-dose group, the mean (±SD) urea-reduction ratio was 66.3±2.5 percent, the single-pool Kt/V was 1.32±0.09, and the equilibrated Kt/V was 1.16±0.08; in the high-dose group, the values were 75.2±2.5 percent, 1.71±0.11, and 1.53±0.09, respectively. Flux, estimated on the basis of beta2-microglobulin clearance, was 3±7 ml per minute in the low-flux group and 34±11 ml per minute in the high-flux group. The primary outcome, death from any cause, was not significantly influenced by the dose or flux assignment: the relative risk of death in the high-dose group as com...

1,670 citations

Journal ArticleDOI
TL;DR: It is suggested 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.

1,478 citations

Journal Article
TL;DR: Cardiovascular Disease in Dialysis Patients Tables: An Overview of Epidemiology of Cardiovascular disease in Children and Work Group Members and Foreword.

1,258 citations

Journal ArticleDOI
TL;DR: It is concluded that clinical and echocardiographic cardiovascular disease are already present in a very high proportion of patients starting ESRD therapy and are independent mortality factors.

1,255 citations