Peter Ivanovich

A trial of darbepoetin alfa in type 2 diabetes and chronic kidney disease.

BACKGROUND Anemia is associated with an increased risk of cardiovascular and renal events among patients with type 2 diabetes and chronic kidney disease. Although darbepoetin alfa can effectively increase hemoglobin levels, its effect on clinical outcomes in these patients has not been adequately tested. METHODS In this study involving 4038 patients with diabetes, chronic kidney disease, and anemia, we randomly assigned 2012 patients to darbepoetin alfa to achieve a hemoglobin level of approximately 13 g per deciliter and 2026 patients to placebo, with rescue darbepoetin alfa when the hemoglobin level was less than 9.0 g per deciliter. The primary end points were the composite outcomes of death or a cardiovascular event (nonfatal myocardial infarction, congestive heart failure, stroke, or hospitalization for myocardial ischemia) and of death or end-stage renal disease. RESULTS Death or a cardiovascular event occurred in 632 patients assigned to darbepoetin alfa and 602 patients assigned to placebo (hazard ratio for darbepoetin alfa vs. placebo, 1.05; 95% confidence interval [CI], 0.94 to 1.17; P=0.41). Death or end-stage renal disease occurred in 652 patients assigned to darbepoetin alfa and 618 patients assigned to placebo (hazard ratio, 1.06; 95% CI, 0.95 to 1.19; P=0.29). Fatal or nonfatal stroke occurred in 101 patients assigned to darbepoetin alfa and 53 patients assigned to placebo (hazard ratio, 1.92; 95% CI, 1.38 to 2.68; P<0.001). Red-cell transfusions were administered to 297 patients assigned to darbepoetin alfa and 496 patients assigned to placebo (P<0.001). There was only a modest improvement in patient-reported fatigue in the darbepoetin alfa group as compared with the placebo group. CONCLUSIONS The use of darbepoetin alfa in patients with diabetes, chronic kidney disease, and moderate anemia who were not undergoing dialysis did not reduce the risk of either of the two primary composite outcomes (either death or a cardiovascular event or death or a renal event) and was associated with an increased risk of stroke. For many persons involved in clinical decision making, this risk will outweigh the potential benefits. (ClinicalTrials.gov number, NCT00093015.)

Erythropoietic response and outcomes in kidney disease and type 2 diabetes

BACKGROUND Non–placebo-controlled trials of erythropoiesis-stimulating agents (ESAs) comparing lower and higher hemoglobin targets in patients with chronic kidney disease indicate that targeting of a lower hemoglobin range may avoid ESA-associated risks. However, target-based strategies are confounded by each patients individual hematopoietic response. METHODS We assessed the relationship among the initial hemoglobin response to darbepoetin alfa after two weight-based doses, the hemoglobin level achieved after 4 weeks, the subsequent darbepoetin alfa dose, and outcomes in 1872 patients with chronic kidney disease and type 2 diabetes mellitus who were not receiving dialysis. We defined a poor initial response to darbepoetin alfa (which occurred in 471 patients) as the lowest quartile of percent change in hemoglobin level (<2%) after the first two standardized doses of the drug. RESULTS Patients who had a poor initial response to darbepoetin alfa had a lower average hemoglobin level at 12 weeks and during follow-up than did patients with a better hemoglobin response (a change in hemoglobin level ranging from 2 to 15% or more) (P<0.001 for both comparisons), despite receiving higher doses of darbepoetin alfa (median dose, 232 μg vs. 167 μg; P<0.001). Patients with a poor response, as compared with those with a better response, had higher rates of the composite cardiovascular end point (adjusted hazard ratio, 1.31; 95% confidence interval [CI], 1.09 to 1.59) or death (adjusted hazard ratio, 1.41; 95% CI, 1.12 to 1.78). CONCLUSIONS A poor initial hematopoietic response to darbepoetin alfa was associated with an increased subsequent risk of death or cardiovascular events as doses were escalated to meet target hemoglobin levels. Although the mechanism of this differential effect is not known, these findings raise concern about current target-based strategies for treating anemia in patients with chronic kidney disease. (Funded by Amgen; ClinicalTrials.gov number, NCT00093015.)

Predictors of fatal and nonfatal cardiovascular events in patients with type 2 diabetes mellitus, chronic kidney disease, and anemia: an analysis of the Trial to Reduce cardiovascular Events with Aranesp (darbepoetin-alfa) Therapy (TREAT)

AIMS This study aims to examine predictors of cardiovascular mortality and morbidity in patients with chronic kidney disease (CKD). Individuals with the triad of diabetes, CKD, and anemia represent a significant proportion of patients with cardiovascular disease and are at particularly high risk for adverse outcomes. METHODS AND RESULTS Using Cox proportional hazards models, we identified independent predictors of the composite of cardiovascular death, myocardial infarction, stroke, hospitalization for myocardial ischemia, or heart failure (HF) in 3,847 patients in the TREAT, 961 (25%) of whom experienced this outcome. The predictors (ranked by χ(2) value) were prior HF (hazard ratio [HR] 1.74, 95% CI 1.51-2.01), age (HR 1.03, 95% CI 1.02-1.04 per year), log urine protein/creatinine ratio (HR 1.19, 95% CI 1.13-1.26 per log unit ), C-reactive protein ≥6.6 mg/L (HR 1.44, 95% CI 1.23-1.69, compared with C-reactive protein ≤3.0 mg/L), and abnormal electrocardiogram (HR 1.42, 95% CI 1.21-1.66 ), all P < .0001. Addition of cardiac-derived biomarkers (subset of first 1,000 patients enrolled) significantly enhanced risk estimation, with N-terminal pro B-type natriuretic peptide becoming the highest ranked predictor of outcome (HR 1.30, 95% CI 1.15-1.46 per log unit, P < .001) and troponin T providing additional predictive information. These biomarkers improved risk classification in 17.8% (9.4%-26.2%) of patients. CONCLUSION In patients with diabetes, CKD, and anemia, cardiovascular risk is most strongly predicted by age, history of HF, C-reactive protein, urinary protein/creatinine ratio, abnormal electrocardiogram, and 2 specific cardiac biomarkers, serum N-terminal pro B-type natriuretic peptide and troponin T, which are elevated in many. These findings suggest ways to improve cardiovascular risk stratification of patients with predialysis CKD, support the concept of cardiorenal syndrome, and may help target therapy.

Stroke in Patients With Type 2 Diabetes Mellitus, Chronic Kidney Disease, and Anemia Treated With Darbepoetin Alfa The Trial to Reduce Cardiovascular Events With Aranesp Therapy (TREAT) Experience

Background— More strokes were observed in the Trial to Reduce Cardiovascular Events With Aranesp Therapy (TREAT) among patients assigned to darbepoetin alfa. We sought to identify baseline characteristics and postrandomization factors that might explain this association. Methods and Results— A multivariate logistic regression model was used to identify baseline predictors of stroke in 4038 patients with diabetes mellitus, chronic kidney disease, and anemia randomized to receive darbepoetin alfa or placebo. To determine whether postrandomization blood pressure, hemoglobin level, platelet count, or treatment dose were responsible for the increased risk related to darbepoetin alfa, we performed a nested case-control analysis (1:10 matching) identifying nonstroke controls with propensity matching. The risk of stroke was doubled with darbepoetin alfa. Overall, 154 patients had a stroke, 101/2012 (5.0%) in the darbepoetin alfa arm and 53/2026 (2.6%) in the placebo arm (hazard ratio 1.9; 95% confidence interval, 1.4–2.7). Independent predictors of stroke included assignment to darbepoetin alfa (odds ratio 2.1; 95% confidence interval, 1.5–2.9), history of stroke (odds ratio 2.0; 95% confidence interval, 1.4–2.9), more proteinuria, and known cardiovascular disease. In patients assigned to darbepoetin alfa, postrandomization systolic and diastolic blood pressure, hemoglobin level, platelet count, and darbepoetin alfa dose did not differ between those with and without stroke. Additional sensitivity analyses using maximal values, latest values, or changes over varying periods of exposure yielded similar results. Conclusions— The 2-fold increase in stroke with darbepoetin alfa in TREAT could not be attributed to any baseline characteristic or to postrandomization blood pressure, hemoglobin, platelet count, or dose of treatment. These readily identifiable factors could not be used to mitigate the risk of darbepoetin alfa–related stroke. Clinical Trial Registration— http://www.clinicaltrials.gov. Unique identifier: NCT00093015.

N-Acetylprocainamide pharmacokinetics in functionally anephric patients before and after perturbation by hemodialysis.

NAPA pharmacokinetics were studied in 6 functionally anephric patients. Distribution and nonrenal elimination of this drug were found to be the same as in individuals with normal renal function but renal clearance was reduced, resulting in a mean elimination t½ of 41.9 hr (6.2 hr in normal subjects). Renal clearance of NAPA correlated well with ClCr. Dialysis removed NAPA from both red blood cells and plasma and increased ClTapproximately fourfold. Dialysis itself resulted in a 77% reduction in Cls that limited the total amount of NAPA removed by this procedure. This reduction in Cls was sustained for at least 3 hr after dialysis and attenuated rebound in plasma NAPA concentrations.

Stroke in Patients With Type 2 Diabetes Mellitus, Chronic Kidney Disease, and Anemia Treated With Darbepoetin Alfa

Background— More strokes were observed in the Trial to Reduce Cardiovascular Events With Aranesp Therapy (TREAT) among patients assigned to darbepoetin alfa. We sought to identify baseline characteristics and postrandomization factors that might explain this association. Methods and Results— A multivariate logistic regression model was used to identify baseline predictors of stroke in 4038 patients with diabetes mellitus, chronic kidney disease, and anemia randomized to receive darbepoetin alfa or placebo. To determine whether postrandomization blood pressure, hemoglobin level, platelet count, or treatment dose were responsible for the increased risk related to darbepoetin alfa, we performed a nested case-control analysis (1:10 matching) identifying nonstroke controls with propensity matching. The risk of stroke was doubled with darbepoetin alfa. Overall, 154 patients had a stroke, 101/2012 (5.0%) in the darbepoetin alfa arm and 53/2026 (2.6%) in the placebo arm (hazard ratio 1.9; 95% confidence interval, 1.4–2.7). Independent predictors of stroke included assignment to darbepoetin alfa (odds ratio 2.1; 95% confidence interval, 1.5–2.9), history of stroke (odds ratio 2.0; 95% confidence interval, 1.4–2.9), more proteinuria, and known cardiovascular disease. In patients assigned to darbepoetin alfa, postrandomization systolic and diastolic blood pressure, hemoglobin level, platelet count, and darbepoetin alfa dose did not differ between those with and without stroke. Additional sensitivity analyses using maximal values, latest values, or changes over varying periods of exposure yielded similar results. Conclusions— The 2-fold increase in stroke with darbepoetin alfa in TREAT could not be attributed to any baseline characteristic or to postrandomization blood pressure, hemoglobin, platelet count, or dose of treatment. These readily identifiable factors could not be used to mitigate the risk of darbepoetin alfa–related stroke. Clinical Trial Registration— http://www.clinicaltrials.gov. Unique identifier: NCT00093015.

Baseline Characteristics in the Trial to Reduce Cardiovascular Events With Aranesp Therapy (TREAT)

BACKGROUND Anemia augments the already high rates of fatal and major nonfatal cardiovascular and renal events in individuals with type 2 diabetes. In 2004, we initiated the Trial to Reduce Cardiovascular Events With Aranesp Therapy (TREAT). This report presents the baseline characteristics and therapies of TREAT participants and subgroups defined by the presence or absence of overt proteinuria and history of cardiovascular disease. The design of TREAT and baseline characteristics also are compared with 2 recent trials of nondialysis patients with chronic kidney disease (CKD) in which treatment with another erythropoiesis-stimulating agent targeting greater hemoglobin levels had either a neutral or adverse effect on clinical outcomes. STUDY DESIGN Randomized trial. SETTING & PARTICIPANTS 4,044 participants with type 2 diabetes, CKD (defined as estimated glomerular filtration rate of 20 to 60 mL/min/1.73 m(2)), and anemia (hemoglobin < or = 11 g/dL) from 24 countries. INTERVENTION Darbepoetin alfa to attempt to increase hemoglobin levels to 13 g/dL compared with placebo. OUTCOMES TREAT is an event-driven design to continue until approximately 1,203 patients experience a primary event: the composite end point of death or cardiovascular morbidity (nonfatal myocardial infarction, congestive heart failure, stroke, or hospitalization for myocardial ischemia). The composite end point of death or need for long-term renal replacement therapy also is a primary end point. CONCLUSIONS With several-fold more patient-years and a placebo arm, TREAT will provide a robust estimate of the safety and efficacy of darbepoetin alfa and generate prospective data regarding the risks of major cardiovascular and renal events in a contemporarily managed cohort of patients with type 2 diabetes, CKD, and anemia.

Hemoperfusion for methotrexate removal.

Removal of methotrexate by Amberlite XAD‐4 hemoperfusion was determined in a patient with metastatic breast carcinoma. During 4 hr of hemoperfusion the plasma concentration of methotrexate fell from 5.5 × 10−7 M to 3.1 × 10−7 M. After hemoperfusion methotrexate concentration increased as a consequence of multicompartmental pharmacokinetics to 5.5 × 10−7 M and then slowly declined. Plasma methotrexate clearance decreased from 79 mllmin 30 min into hemoperfusion to 28 mllmin at the conclusion. In vitro clearance of methotrexate by 17 artificial kidneys. Amberlite XAD‐4. and uncoated charcoal was determined. Uncoated charcoal had the greatest clearance of methotrexate of all the devices tested. We conclude that: (1) Amberlite XAD‐4 transiently reduces plasma methotrexate concentration; (2) in vitro. charcoal hemoperfusion is more effective than XAD‐4 in removing methotrexate; (3) as a consequence of the multicompartmental pharmacokinetics of methotrexate a postperfusion rebound in plasma methotrexate concentration is to be expected.

IgE against ethylene oxide-altered human serum albumin in patients with anaphylactic reactions to dialysis☆

We have measured total antibody and IgE directed against ethylene oxide-altered human serum albumin (ETO-HSA) in the sera of 24 patients who have experienced anaphylaxis during hemodialysis and of 41 patients who have not had such episodes during hemodialysis. ETO is used to sterilize dialyzers and other medical equipment. The geometric mean level of IgE to ETO-HSA in patients with reactions (0.9 ng ETO-HSA bound to IgE per milliliter of serum) is significantly higher than in nonreacting patients (0.1 ng/ml, p less than 0.0001). Sixteen of 24 patients with reactions had detectable levels of IgE to ETO-HSA, whereas only three of 41 nonreacting patients had detectable levels (p less than 0.0001 chi-square). The geometric mean level of total antibody to ETO-HSA is also significantly higher in patients with reactions (270 ng ETO-HSA bound per milliliter) than in nonreacting patients (31 ng/ml, p less than 0.0001). Fourteen of 24 patients with reactions but only four of 39 nonreacting patients had total antibody binding of ETO-HSA (p less than 0.0001 chi-square). These data extend our previous observations on a small group of 13 patients receiving hemodialysis (seven patients with reactions, and six nonreacting patients) and clearly demonstrate an association between the presence of IgE or total antibody to ETO-HSA and immediate anaphylactic reactions in this group of 65 patients receiving hemodialysis.

Biocompatibility of Dialysis Membranes

inTroDuCTion The interaction between biological tissues and artificial materials is becoming increasingly important in the field of biomedicine. Synthetic grafts are implanted in the body and different cells will be exposed to these foreign materials. The interactions between such synthetic vascular grafts and blood components (granulocytes and platelets) have successfully been investigated by using microcalorimetry [ 1 ]. Another biocompatibility problem exists for hemodialysis membranes and blood. This application note deals with the microcalorimetric evaluation of the interactions between human granulocytes and different materials used for dialysis reported in detail by Monti, Ljunggren and co-workers [2]. Granulocytes are characterised by a low basal metabolism and a large metabolic burst when exposed to foreign particles. The basal metabolism as well as the metabolism associated with phagocytosis was measured for granulocytes in contact with different materials. As shown here, the efficacy of different materials for use with living cells is easily monitored by using TAM.