Trends in anemia management among US hemodialysis patients

Relationships among the Dosage of Erythropoiesis-Stimulating Agents, Erythropoietin Resistance Index, and Mortality in Maintenance Hemodialysis Patients

BACKGROUND

Erythropoiesis-stimulating agents (ESAs) constitute an important treatment option for anemia in hemodialysis (HD) patients. We investigated the relationships among the dosage of ESA, erythropoietin resistance index (ERI) scores, and mortality in Chinese MHD patients.

METHODS

This multicenter observational retrospective study included MHD patients from 16 blood purification centers (n = 824) who underwent HD in 2011-2015 and were followed up until December 31, 2016. We collected demographic variables, HD parameters, laboratory values, and ESA dosages. Patients were grouped into quartiles according to ESA dosage to study the effect of ESA dosage on all-cause mortality. The ERI was calculated as follows: ESA (IU/week)/weight (kg)/hemoglobin levels (g/dL). We also compared outcomes among the patients stratified into quartiles according to ERI scores. We used the Cox proportional hazards model to measure the relationships between the ESA dosage, ERI scores, and all-cause mortality. Using propensity score matching, we compared mortality between groups according to ERI scores, classified as either > or ≤12.80.

RESULTS

In total, 824 patients were enrolled in the study; 200 (24.3%) all-cause deaths occurred within the observation period. Kaplan-Meier analyses showed that patients administered high dosages of ESAs had significantly worse survival than those administered low dosages of ESAs. A multivariate Cox regression identified that high dosages of ESAs could significantly predict mortality (ESA dosage >10,000.0 IU/week, HR = 1.59, 95% confidence intervals (CIs) (1.04, 2.42), and p = 0.031). Our analysis also indicated a significant increase in the risk of mortality in patients with high ERI scores. Propensity score matching-analyses confirmed that ERI > 12.80 could significantly predict mortality (HR = 1.56, 95% CI [1.11, 2.18], and p = 0.010).

CONCLUSIONS

Our data suggested that ESA dosages >10,000.0 IU/week in the first 3 months constitute an independent predictor of all-cause mortality among Chinese MHD patients. A higher degree of resistance to ESA was related to a higher risk of all-cause mortality.

Economic Benefits of Switching From Intravenous to Subcutaneous Epoetin Alfa for the Management of Anemia in Hemodialysis Patients

Background:

Erythropoiesis-stimulating agents including epoetin alfa have been a mainstay of anemia management in patients with chronic kidney disease. Although the standard practice has been to administer epoetin alfa to patients on hemodialysis (HD) intravenously (IV), subcutaneous (SQ) epoetin alfa is longer acting and achieve the same target hemoglobin level to be maintained at a reduced dose and cost.

Objective:

The primary objective of this study was to determine the economic benefits of change in route of epoetin alfa administration from IV to SQ in HD patients. The secondary objectives were (1) to determine the differences in epoetin alfa doses at the pre-switch (IV) and post-switch period (SQ) and (2) to determine serum hemoglobin concentration, transferrin saturation, ferritin level, IV iron dose and cost in relationship to route of epoetin alfa administration.

Design:

This retrospective observational study included patients who transitioned from IV to SQ epoetin alfa.

Setting:

Two HD sites in southern Saskatchewan (Regina General Hospital, and Wascana Dialysis Unit, Regina) and 2 sites in northern Saskatchewan (St. Paul’s [SPH] Hospital, and SPH Community Renal Health Center, Saskatoon).

Patients:

The study includes 215 patients who transitioned from IV to SQ and were alive at the end of 12-month follow-up period.

Measurements:

We calculated the dose and cost of different routes of epoetin alfa administration/patient month. Also, serum hemoglobin, markers of iron stores (transferrin saturation and ferritin), IV iron dose, and cost were determined in relation to route of epoetin alfa administration.

Methods:

Data were gathered from 6 months prior (IV) to 12 months after switching treatment to SQ. The paired t-test and Wilcoxon signed-rank test were used to compare variables between pre-switch (IV) and post-switch (SQ) period.

Results:

The median cost (interquartile range) of epoetin alfa/patient-month decreased from (CAD508.3 [CAD349-CAD900.8]) pre-switch (IV) to (CAD381.2 [CAD247-CAD681]) post-switch (SQ) (P < .001), a decrease of 25%. The median epoetin alfa dose/patient-month reduced from (38 500 [25 714.3-64 166.5] international unit) pre-switch to (26 750.3 [17 362.6-48 066] IU) post-switch (P < .001), a decrease of 30.51%. The mean hemoglobin concentration (± standard deviation) for patients in both periods remained stable (103.3 ± 9.2 vs 104.3 ± 13.3 g/L, P = .34) and within the target range. There were no significant differences in transferrin saturation, ferritin, and IV iron dose and cost between the 2 study periods.

Limitations:

We were unable to consistently obtain information across all the sites on hospitalizations, inflammatory markers, nutritional status, and gastrointestinal bleeding. In addition, as our study sample was subject to survival bias, we cannot generalize our study results to other populations.

Conclusions:

We have shown that administering epoetin alfa SQ in HD patients led to a 30.51% reduction in dose and 25% reduction in cost while achieving equivalent hemoglobin levels. Given the cost sparing advantages without compromising care while achieving comparable hemoglobin levels, HD units should consider converting to SQ mode of administration.

Trial registration:

The study was not registered on a publicly accessible registry as it was a retrospective chart review and exempted from review by the Research Ethics Board of the former Regina Qu’Appelle Health Region.

Gender Differences in Dose of Erythropoietin to Maintain Hemoglobin Target in Hemodialysis Patients

Dialysis patients receiving erythropoietin (EPO) for anemia management are a challenge due to the significant interindividual variability in erythropoietic response. Our objective was to determine if there is a gender-dependent difference in the EPO doses required to maintain the hemoglobin (Hb) targets in adult patients undergoing hemodialysis. We conducted a historic cohort study with a 12-month follow-up. We include patients with the Hb target, normal serum albumin, and normal transferrin saturation index. Monthly data were gathered for the following: Hb level, EPO doses, and intravenous iron doses. In the 11 hemodialysis facilities included, 1844 patients were on hemodialysis. We considered 389 patients for follow-up, 190 of which were excluded mainly for failing to keep the Hb level in the established range. The final cohort for analysis included 141 men (70.9%) and 58 women (29.1%). At baseline, men weighed more than women (P < 0.001). At the end of the follow-up period, the EPO required to maintain Hb level between 10 and 13 g/dl was significantly higher in women in the monthly dose, weekly dose, and weekly EPO dose/patient weight, with no difference in the monthly iron dose. There was a significant association between female gender and the use of high EPO doses (odds ratio, 4.1; 95% confidence interval, 1.4–12.2; P = 0.01). Our study demonstrates that women require higher doses of EPO to achieve Hb targets.

Prevalence and Correlates of Anemia and Uncontrolled Anemia in Chronic Hemodialysis Patients – The Campania Dialysis Registry

Background

This study investigated prevalence and correlates of anemia and uncontrolled anemia in chronic hemodialysis patients.

Methods

A cross-sectional analysis was performed on registry data for 2,746 chronic (<6 months) hemodialysis patients aged 25–84. Data collection included years of dialysis, hours of dialysis/wk, disease causing hemodialysis, body mass index (BMI), erythropoietin (EPO) treatment, hemoglobin, markers of viral hepatitis, serum albumin, calcium, and phosphorus.

Results

Prevalence was 88.7% for anemia (hemoglobin <11 g/100 mL and EPO treatment at any Hb level), 39.4% for uncontrolled anemia (hemoglobin<11 g/100 mL). Gender, years of dialysis, hereditary cystic kidney disease (HCKD), and low BMI (<24 kg/m2) were independent correlates of anemia (P<0.001). Gender, HCKD, low BMI, serum albumin and calcium were independent correlates of uncontrolled anemia (P<0.05). An interaction was found between age (not correlated with anemia and uncontrolled anemia) and the association of gender with uncontrolled anemia (P<0.05). EPO doses were higher in patients with high prevalence of uncontrolled anemia than in patients with low prevalence (i.e., women vs men, other diseases vs HCKD, low vs not-low BMI, P<0.01). Gender, years of dialysis, HCKD, BMI, serum albumin, and calcium were independent correlates of the hemoglobin/EPO dose ratio in patients on EPO treatment (P<0.05).

Conclusion

Anemia and uncontrolled anemia are more frequent in hemodialysis patients with short-term dialysis, diseases other than HCKD, low BMI, and female gender. Gender effect was lower in elderly patients. Uncontrolled anemia was also associated with low serum albumin and calcium, suggesting that these parameters are indices of EPO resistance.

Renal association clinical practice guideline on Anaemia of Chronic Kidney Disease

Anaemia is a commonly diagnosed complication among patients suffering with chronic kidney disease. If left untreated, it may affect patient quality of life. There are several causes for anaemia in this patient population. As the kidney function deteriorates, together with medications and dietary restrictions, patients may develop iron deficiency, resulting in reduction of iron supply to the bone marrow (which is the body organ responsible for the production of different blood elements). Chronic kidney disease patients may not be able to utilise their own body's iron stores effectively and hence, many patients, particularly those receiving haemodialysis, may require additional iron treatment, usually provided by infusion.With further weakening of kidney function, patients with chronic kidney disease may need additional treatment with a substance called erythropoietin which drives the bone marrow to produce its own blood. This substance, which is naturally produced by the kidneys, becomes relatively deficient in patients with chronic kidney disease. Any patients will eventually require treatment with erythropoietin or similar products that are given by injection.Over the last few years, several iron and erythropoietin products have been licensed for treating anaemia in chronic kidney disease patients. In addition, several publications discussed the benefits of each treatment and possible risks associated with long term treatment. The current guidelines provide advice to health care professionals on how to screen chronic kidney disease patients for anaemia, which patients to investigate for other causes of anaemia, when and how to treat patients with different medications, how to ensure safe prescribing of treatment and how to diagnose and manage complications associated with anaemia and the drugs used for its treatment.

A threshold trajectory was revealed by isolating the effects of hemoglobin rate of rise in anemia of chronic kidney disease

BACKGROUND

To assess cardiovascular risk among various hemoglobin (Hb) rates of rise (RoR) in chronic kidney disease (CKD) patients with anemia who have initiated therapy with erythropoiesis stimulating agents (ESAs).

METHODS

Observational cohort of CKD patients initiating ESA therapy from the Centricity® database, 1990-2011. Proportional hazards models tested the hypothesis that a slower Hb RoR (0 < g/dl/month ⩽ 0.125) is associated with a lower cardiovascular (CV) incidence [composite of fatal/nonfatal myocardial infarction (MI) and stroke] compared with faster RoR (0.125 < g/dl/month ⩽ 2.0, and >2.0 g/dl/month).

RESULTS

A total of 9220 patients receiving ESAs were followed for an average of 3.1 years. Slow (group B) RoR versus medium (group C') and fast (group D') RoR in Hb, throughout all Hb milestones, was associated with lower risk of the composite endpoint [B (slow) versus D' (fast) [hazard ratio (HR) = 0.20 (0.11, 0.39), p < 0.0001]; B versus C' (medium) [HR = 0.34 (0.19, 0.62), p = 0.0004], and C' versus D' [HR = 0.60 (0.42, 0.85), p = 0.005]]. Within achieved Hb milestones, HRs were: B versus D' at milestone ⩾ 14.1 g/dl [HR = 0.17 (0.05, 0.56); p = 0.004] and at milestone 12.6-14.0 [HR = 0.18 (0.07, 0.46), p = 0.0004].

CONCLUSION

Rapid Hb rise is associated with adverse CV outcomes, with markedly lower risk for rates below a threshold trajectory of 0.125 g/dl/month, even with complete correction.

Effect of intravenous iron use on hospitalizations in patients undergoing hemodialysis: a comparative effectiveness analysis from the DEcIDE-ESRD study

BACKGROUND

Intravenous iron use in hemodialysis patients has greatly increased over the last decade, despite limited studies on the safety of iron.

METHODS

We studied the association of receipt of intravenous iron with hospitalizations in an incident cohort of hemodialysis patients. We examined 9544 patients from Dialysis Clinic, Inc. (DCI). We ascertained intravenous iron use from DCI electronic medical record and USRDS data files, and hospitalizations through Medicare claims. We examined the association between iron exposure accumulated over 1-, 3- or 6-month time windows and incident hospitalizations in the follow-up period using marginal structural models accounting for time-dependent confounders. We performed sensitivity analyses including recurrent events models for multiple hospitalizations and models for combined outcome of hospitalization and death.

RESULTS

There were 22 347 hospitalizations during a median follow-up of 23 months. Higher cumulative dose of intravenous iron was not associated with all-cause, cardiovascular or infectious hospitalizations [HR 0.97 (95% CI: 0.77-1.22) for all-cause hospitalizations comparing >2100 mg versus 0-900 mg of iron over 6 months]. Findings were similar in models examining the risk of hospitalizations in 1- and 3-month windows [HR 0.88 (95% CI: 0.79-0.99) and HR 0.88 (95% CI: 0.74-1.03), respectively] or the risk of combined outcome of hospitalization and death in the 6-month window [HR 0.98 (95% CI: 0.78-1.23)].

CONCLUSIONS

Higher cumulative dose of intravenous iron may not be associated with increased risk of hospitalizations in hemodialysis patients. While clinical trials are needed, employing higher iron doses to reduce erythropoiesis-stimulating agents does not appear to increase morbidity in routine clinical care.

Does erythropoietin have a role in the treatment of β-hemoglobinopathies?

This review presents the indications and contraindications (pros and cons) for the potential use of erythropoietin (Epo) as a treatment in β-thalassemia and sickle cell anemia (SCA). Its high cost and route of administration (by injection) are obvious obstacles, especially in underdeveloped countries, where thalassemia is prevalent. We believe that from the data summarized in this review, the time has come to define, by studying in vitro and in vivo models, as well as by controlled clinical trials, the rationale for treating patients with various forms of thalassemia and SCA with Epo alone or in combination with other medications.

Cardiovascular toxicity of epoetin-alfa in patients with chronic kidney disease

BACKGROUND

Recombinant erythropoietin has become a routine component of care of patients with chronic kidney disease reducing the need for blood transfusions but raising the risks for cardiovascular events. We undertook this secondary analysis of subjects enrolled in the Correction of Hemoglobin and Outcomes in Renal Insufficiency (CHOIR) trial to examine the interrelationships between epoetin-alfa maintenance doses utilized and achieved hemoglobin (Hb) irrespective of treatment target and randomized allocation.

METHODS

We performed a post hoc analysis from the CHOIR trial. Inclusion criteria were Hb <11.0 g/dl and estimated glomerular filtration rates of 15-50 ml/min/1.73 m(2). To be included in the present analysis, subjects needed to be free of the composite event at 4 months, receive epoetin-alfa, and have ≥1 postbaseline Hb measurement. The mean weekly dose of epoetin-alfa received up to the time of first event or censure was the main exposure variable, while the achieved Hb at month 4 was the confounder representing the subject's underlying response to treatment. The primary outcome was the composite of death, heart failure hospitalization, stroke, or myocardial infarction. A Cox proportional hazard regression model was used in time-to-event analysis.

RESULTS

Among 1,244 subjects with complete data, the average weekly dose of epoetin-alfa ranged 143.3-fold from 133 to 19,106 units/week at the time of first event or censure. Cox proportional hazard analysis found that those in the middle tertile of Hb achieved (>11.5 to <12.7 g/dl) and the lowest tertile of epoetin-alfa dose exposure level (<5,164 units/week) had the lowest risk. Irrespective of Hb achieved, the relative risk in the highest tertile (>10,095 units/week) of epoetin-alfa dose exposure level was significantly escalated (hazard ratios ranged from 2.536 to 3.572, p < 0.05, when compared to the group of middle Hb tertile and lowered dose tertile). In a multivariable model that adjusted for achieved Hb, albumin, cholesterol, age, prior heart failure, prior stroke, prior deep venous thrombosis, atrial fibrillation or malignancy, the average weekly dose had a significant (p = 0.005) relative risk of 1.067 per 1,000 units of epoetin-alfa for the primary end point.

CONCLUSIONS

In the CHOIR trial, average epoetin-alfa doses >10,095 units/week were associated with increased risks for cardiovascular events irrespective of the Hb achieved within the first 4 months of treatment. These data suggest the weekly epoetin-alfa dose and not the Hb achieved was a principal determinant in the primary outcome observed implicating a cardiovascular toxicity of this erythrocyte-stimulating agent.

Induction of erythropoiesis using human vascular networks genetically engineered for controlled erythropoietin release

For decades, autologous ex vivo gene therapy has been postulated as a potential alternative to parenteral administration of recombinant proteins. However, achieving effective cellular engraftment of previously retrieved patient cells is challenging. Recently, our ability to engineer vasculature in vivo has allowed for the introduction of instructions into tissues by genetically modifying the vascular cells that build these blood vessels. In the present study, we genetically engineered human blood-derived endothelial colony-forming cells (ECFCs) to express erythropoietin (EPO) under the control of a tetracycline-regulated system, and generated subcutaneous vascular networks capable of systemic EPO release in immunodeficient mice. These ECFC-lined vascular networks formed functional anastomoses with the mouse vasculature, allowing direct delivery of recombinant human EPO into the bloodstream. After activation of EPO expression, erythropoiesis was induced in both normal and anemic mice, a process that was completely reversible. This approach could relieve patients from frequent EPO injections, reducing the medical costs associated with the management of anemia. We propose this ECFC-based gene-delivery strategy as a viable alternative technology when routine administration of recombinant proteins is needed.

Erythropoiesis-stimulating agent responsiveness and mortality in hemodialysis patients: results from a cohort study from the dialysis registry in Japan

BACKGROUND

Patient responsiveness to erythropoiesis-stimulating agents (ESAs), notoriously difficult to measure, has attracted attention for its association with mortality. We defined categories of ESA responsiveness and attempted to clarify their association with mortality.

STUDY DESIGN

Cohort study.

SETTING & PARTICIPANTS

Data from Japan's dialysis registry (2005-2006), including 95,460 adult hemodialysis patients who received ESAs.

PREDICTOR

We defined 6 categories of ESA responsiveness based on a combination of ESA dosage (low [<6,000 U/wk] or high [≥6,000 U/wk]) and hemoglobin level (low [<10 g/dL], medium [10-11.9 g/dL], or high [≥12 g/dL]), with medium hemoglobin level and low-dose ESA therapy as the reference category.

OUTCOMES

All-cause and cardiovascular mortality during 1-year follow-up.

MEASUREMENTS

HRs were estimated using a Cox model for the association between responsiveness categories and mortality, adjusting for potential confounders such as age, sex, postdialysis weight, dialysis duration, comorbid conditions, serum albumin level, and transferrin saturation.

RESULTS

Median ESA dosage (4,500-5,999 U/wk) was used as a cutoff point, and mean hemoglobin level was 10.1 g/dL in our cohort. Of 95,460 patients during follow-up, 7,205 (7.5%) died of all causes, including 5,586 (5.9%) cardiovascular deaths. Low hemoglobin levels and high-dose ESA therapy were both associated with all-cause mortality (adjusted HRs, 1.18 [95% CI, 1.09-1.27] for low hemoglobin level with low-dose ESA and 1.44 [95% CI, 1.34-1.55] for medium hemoglobin level with high-dose ESA). Adjusted HRs for high-dose ESA with low hemoglobin level (hyporesponsiveness) were 1.94 (95% CI, 1.82-2.07) for all-cause and 2.02 (95% CI, 1.88-2.17) for cardiovascular mortality. We also noted the interaction between ESA dosage and hemoglobin level on all-cause mortality (likelihood ratio test, P = 0.002).

LIMITATIONS

Potential residual confounding from unmeasured factors and single measurement of predictors.

CONCLUSIONS

Mortality can be affected by ESA responsiveness, which may include independent and interactive effects of ESA dose and hemoglobin level. Responsiveness category has prognostic importance and clinical relevance in anemia management.

Trends in the incidence, demographics, and outcomes of end-stage renal disease due to lupus nephritis in the US from 1995 to 2006

OBJECTIVE

This study was undertaken to investigate whether recent advances in lupus nephritis treatment have led to changes in the incidence of end-stage renal disease (ESRD) secondary to lupus nephritis, or in the characteristics, treatments, and outcomes of patients with lupus nephritis ESRD.

METHODS

Patients with incident lupus nephritis ESRD (1995-2006) were identified in the US Renal Data System. Trends in sociodemographic and clinical characteristics were assessed. We tested for temporal changes in standardized incidence rates (SIRs) for sociodemographic groups using Poisson regression. Changes in rates of waitlisting for kidney transplant, kidney transplantation, and all-cause mortality were examined using crude and adjusted time-to-event analyses.

RESULTS

We identified 12,344 incident cases of lupus nephritis ESRD. Mean age at ESRD onset was 41 years; 81.6% of the patients were women and 49.5% were African American. SIRs for lupus nephritis ESRD among those who were ages 5-39 years, African American, or lived in the southeastern US increased significantly from 1995 to 2006. Increases in body mass index and in the prevalence of both diabetes mellitus and hypertension were detected. Mean serum hemoglobin level at ESRD onset increased, while that of serum creatinine decreased over time. More patients received hemodialysis and fewer received peritoneal dialysis. There was a slight increase in the frequency of preemptive kidney transplantation at ESRD onset, but kidney transplantation rates within the first 3 years of ESRD declined. Mortality did not change over the 12 years of study.

CONCLUSION

Our findings indicate that the characteristics of patients with lupus nephritis ESRD and initial therapies have changed in recent years. While SIRs rose in younger patients, among African Americans, and in the South, outcomes did not improve in over a decade of evaluation.

The antioxidant effect of erythropoietin on thalassemic blood cells

Because of its stimulating effect on RBC production, erythropoietin (Epo) is used to treat anemia, for example, in patients on dialysis or on chemotherapy. In β-thalassemia, where Epo levels are low relative to the degree of anemia, Epo treatment improves the anemia state. Since RBC and platelets of these patients are under oxidative stress, which may be involved in anemia and thromboembolic complications, we investigated Epo as an antioxidant. Using flow-cytometry technology, we found that in vitro treatment with Epo of blood cells from these patients increased their glutathione content and reduced their reactive oxygen species, membrane lipid peroxides, and external phosphatidylserine. This resulted in reduced susceptibility of RBC to undergo hemolysis and phagocytosis. Injection of Epo into heterozygous (Hbb(th3/+)) β-thalassemic mice reduced the oxidative markers within 3 hours. Our results suggest that, in addition to stimulating RBC and fetal hemoglobin production, Epo might alleviate symptoms of hemolytic anemias as an antioxidant.

Association of quarterly average achieved hematocrit with mortality in dialysis patients: a time-dependent comorbidity-adjusted model

BACKGROUND

Recent publications suggest that increased mortality is associated with high hematocrit targets in erythropoietin-stimulating agent-treated patients with chronic kidney disease. We aim to further inform the debate about optimal hematocrit targets, advancing the hypothesis that the current hematocrit target may not optimize the survival of patients with end-stage renal disease.

STUDY DESIGN

Cross-sectional observational study.

SETTING & PARTICIPANTS

Medicare dialysis patients from 2002 to 2004 (n = 393,967).

FACTORS

Quarterly average hematocrit and erythropoietin alfa (EPO) dose.

OUTCOMES

Mortality hazard ratios from time-dependent Cox proportional hazard models, adjusting for comorbidities.

RESULTS

N = 2,712,197 patient-facility quarters. During the study, 100,086 deaths were identified. Percentages of patient quarters within each hematocrit category: hematocrit less than 27% (2.0%), 27% to 28.49% (1.7%), 28.5% to 29.9% (2.9%), 30% to 31.49% (5.2%), 31.5% to 32.99% (9.0%), 33% to 34.49% (14.9%), 34.5% to 35.99% (19.2%), 36% to 37.49% (18.0%), 37.5% to 38.99% (12.0%), 39% to 40.49% (6.4%), 40.5% to 41.99% (3.0%), and 42% or greater (3.1%). Mortality hazard ratios from the fully adjusted model: hematocrit less than 27% (3.11), 27% to 28.49% (2.60), 28.5% to 29.9% (2.14), 30% to 31.49% (1.80), 31.5% to 32.99% (1.44), 33% to 34.49% (1.17), 34.5% to 35.99% (reference), 36% to 37.49% (0.98), 37.5% to 38.99% (1.01), 39% to 40.49% (1.13), 40.5% to 41.99% (1.32), and 42% or greater (1.57).

LIMITATIONS

First, potential confounding by indication related to associations between underlying illness and mortality, anemia, and EPO responsiveness. Second, Medicare claims data reflect a range of conditions and degrees of severity not easily translated into the clinical context. Third, for Medicare claims, EPO reporting is not required if EPO is not billed. Greater than 95% of "missing hematocrit" quarters are "EPO = 0" patient quarters. Interpretation of results for the missing hematocrit and EPO = 0 use categories is complicated by data source limitations.

CONCLUSIONS

We show an association between mortality and low hematocrit in dialysis patients, in part reflecting the presence of comorbidities. We also show an association between increased mortality and high hematocrit. Additional interventional trials should be undertaken to better define the optimal target for anemia management in patients with end-stage renal disease, with careful prospective identification of underlying comorbidities and clinical factors contributing to high erythropoietin-stimulating agent requirement.

The controversy surrounding hemoglobin and erythropoiesis-stimulating agents: what should we do now?

Treatment of the anemia of chronic kidney disease (CKD) with erythropoiesis-stimulating agents (ESAs) has been intensely debated during the past 2 years. Treatment with ESAs has transformed the lives of millions of patients with CKD, with fewer blood transfusions and improved quality of life. However, randomized trials have suggested that targeting greater hematocrits/hemoglobin levels and/or exposure to high doses of ESAs is associated with a greater risk of cardiovascular complications and mortality. The US Food and Drug Administration has inserted a boxed warning for ESAs and, along with the National Kidney Foundation-Kidney Disease Outcomes Quality Initiative (KDOQI), decreased recommended target hemoglobin ranges for ESA therapy. The Centers for Medicare & Medicaid Services has decreased ESA dosing recommendations in the Medicare claims policy for ESAs. Managing the anemia of CKD in the era of the hemoglobin level and ESA controversy has required aiming for appropriate hemoglobin levels, using the lowest effective ESA dose, and better managing the problem of ESA hyporesponsiveness.

Interpretation and review of health-related quality of life data in CKD patients receiving treatment for anemia

Recent evidence suggests that targeting higher hemoglobin values with erythropoiesis stimulating agents (ESAs) may lack mortality benefits and may even result in adverse cardiovascular complications when used in chronic kidney disease patients. However, ESAs are frequently reported to result in improvements in health-related quality of life (HRQOL). The purpose of this review is to evaluate the magnitude and nature of ESA-associated improvements in HRQOL, as well as to understand how to interpret the clinical significance of HRQOL data. HRQOL findings should be analyzed not by statistical significance but rather by using a minimal clinically important difference approach, or, alternatively, a distribution-based approach (such as Cohen's effect size). HRQOL domains that are most improved with ESAs relate to physical symptoms, vitality, energy, and performance; domains of social functioning and mental health show modest improvement, whereas the domains of emotional functioning and pain show very little improvement. Additional domains not measured by commonly used instruments (such as the SF-36) that have been shown to improve with ESAs include sleep, cognitive functioning, and sexual functioning. The maximal increase in HRQOL per incremental increase in hemoglobin appears to occur in the range of 10-12 g/dl. Beyond this range, additional normalization of hemoglobin (to 12-14 g/dl) results in continued (albeit blunted) improvements in HRQOL.

Secondary analysis of the CHOIR trial epoetin-alpha dose and achieved hemoglobin outcomes

Trials of anemia correction in chronic kidney disease have found either no benefit or detrimental outcomes of higher targets. We did a secondary analysis of patients with chronic kidney disease enrolled in the Correction of Hemoglobin in the Outcomes in Renal Insufficiency trial to measure the potential for competing benefit and harm from achieved hemoglobin and epoetin dose trials. In the 4 month analysis, significantly more patients in the high-hemoglobin compared to the low-hemoglobin arm were unable to achieve target hemoglobin and required high-dose epoetin-alpha. In unadjusted analyses, the inability to achieve a target hemoglobin and high-dose epoetin-alpha were each significantly associated with increased risk of a primary endpoint (death, myocardial infarction, congestive heart failure or stroke). In adjusted models, high-dose epoetin-alpha was associated with a significant increased hazard of a primary endpoint but the risk associated with randomization to the high hemoglobin arm did not suggest a possible mediating effect of higher target via dose. Similar results were seen in the 9 month analysis. Our study demonstrates that patients achieving their target had better outcomes than those who did not; and among subjects who achieved their randomized target, no increased risk associated with the higher hemoglobin goal was detected. Prospective studies are needed to confirm this relationship and determine safe dosing algorithms for patients unable to achieve target hemoglobin.

The role of anemia management in improving outcomes for African-Americans with chronic kidney disease

Chronic kidney disease (CKD) is a serious threat to African-American public health. In this population CKD progresses to end-stage renal disease (ESRD) at quadruple the rate in Caucasians. Factors fueling progression to ESRD include diabetes and hypertension, which show high prevalences and accelerated renal damage in African- Americans, as well as possible nutritional, socioeconomic, and genetic factors. Anemia, a common and deleterious complication of CKD, is more prevalent and severe in African-American than Caucasian patients at each stage of the disease. Proactive management of diabetes, hypertension, anemia, and other complications throughout the course of CKD can prevent or delay disease progression and alleviate the burden of ESRD for the African-American community. Currently, African-Americans with CKD are less likely than Caucasian patients to receive anemia treatment before and after the onset of dialysis. Although African-Americans often require higher doses of erythropoiesis-stimulating agents, this may result from late treatment initiation, lower hemoglobin levels, or the presence of comorbidities such as diabetes and inflammation, although racial differences in response cannot be excluded. This review explores racial-specific challenges and potential solutions in renal anemia management to improve outcomes in African-American patients.

CERA: third-generation erythropoiesis-stimulating agent

BACKGROUND

For 20 years, anemia has been treated with erythropoietin-stimulating agents (ESA). Until recently there have been only two ESA: recombinant erythropoietin and darbepoetin. In 2007 a third agent was approved for clinical use, CERA.

METHODS

This review covers all of the peer-reviewed literature regarding ESA. The review also covers unique aspects of the regulatory publications with the FDA and European Agency for the Evaluation of Medicinal Products.

RESULTS

CERA is effective at correcting renal anemia. Compared to previous ESA, CERA has a dramatically lengthened half-life, making it the only ESA licensed for once-a-month dosing. However, like the previous ESA, CERA has not been shown to reduce morbidity or mortality and has only been shown to correct anemia and improve quality of life.

The effect of epoetin dose on hematocrit

Nearly all dialysis patients receive epoetin therapy to treat anemia. Using the United States Renal Data System, we monitored the 14,001 patients aged 65 and older who started dialysis and epoetin treatment in 2003-2004. We estimated the dose-response relationship for the average epoetin dose and hematocrit during a 3-month initiation and subsequent 3-month maintenance phase using a marginal structural model to adjust for measured time-dependent confounding by indication. During the initiation phase, an S-shaped dose-response relationship for average weekly epoetin dose and hematocrit response was found. Average hematocrit levels rose as the epoetin dose was increased from 9,000 to approximately 22,500 units per week. At higher doses, the effect of increasing epoetin was minimal with average hematocrit levels plateauing at 38.5%, but this was less evident in the maintenance phase. Among patients who reached this phase, doses required to maintain the hematocrit level were lower than those required to achieve similar hematocrit levels in the initiation phase. The dose-response curve found in our study suggests that published recommendations for starting dose are appropriate, and a starting dose of 7,500-15,000 units per week can maintain the hematocrit level in the desired target range of 33-36%.

Dialysis adequacy and response to erythropoiesis-stimulating agents: what is the evidence base?

Despite an increase in the use and average dose of erythropoiesis-stimulating agents (ESA) over the past 15 years, a substantial percentage of patients still do not achieve hemoglobin targets recommended by international guidelines. A clear relationship among hemoglobin or hematocrit levels, ESA dose, and increase in dialysis dose has been pointed out by a number of prospective or retrospective studies. This is particularly true in patients receiving inadequate dialysis. Increasing attention also has been paid to the relationship between dialysis, increased inflammatory stimulus, and ESA response because dialysate contamination and low-compatible treatments may increase cytokine production and consequently inhibit erythropoiesis. The biocompatibility of dialysis membranes and flux are other important factors. However, in highly selected, adequately dialyzed patients without iron or vitamin depletion, the effect of these treatment modalities on anemia seems to be smaller than expected. The role of on-line treatments still is controversial given that it is still difficult to discriminate between the effect of on-line hemodiafiltration per se from that of an increased dialysis dose. Very preliminary results obtained with short or long nocturnal daily hemodialysis on anemia correction are encouraging.

Anaemia and mortality in haemodialysis patients: interaction of propensity score for predicted anaemia and actual haemoglobin levels

BACKGROUND

Haemoglobin levels in haemodialysis patients could represent unknown comorbidities, more severe levels of known comorbidities, as well as therapeutic choice. Thus, integrating factors predictive of anaemia with actual haemoglobin levels might improve prognostic discrimination.

METHODS

We retrospectively studied 93,087 patients who started haemodialysis between 1998 and 2000. Clinical and treatment factors from months 4 through 9, derived from Medicare claims, were used to develop propensity scores for anaemia (mean haemoglobin <11 g/dl). Tertiles of propensity scores were interacted with five levels of actual mean haemoglobin to form 15 groups, ranging from low (anaemia) probability with (mean) haemoglobin <10 g/dl to high probability with haemoglobin >or=13 g/dl. Cox proportional hazards regression evaluated mortality and first hospitalization among these groups.

RESULTS

The anaemia propensity score improved overall prognostic discrimination. Propensity score adjustment significantly improved prediction of mortality (P<0.0001) after covariate adjustments including haemoglobin. For mortality, the highest and lowest adjusted hazard ratios (AHR) appeared in these groups, respectively: high probability with haemoglobin <10 g/dl (AHR 1.64 [1.54, 1.75], P<0.0001), and low probability with haemoglobin 12 to <13 g/dl (AHR 0.79 [0.74, 0.85], P<0.0001). Higher haemoglobin levels were associated with lower mortality even after propensity score adjustment. Similar patterns resulted for first hospitalization; however, the interaction was significant only for hospitalization (P = 0. 0212).

CONCLUSIONS

Integrating factors predictive of anaemia improves overall prognostic discrimination. Propensity score adjustment refines the prognostic association of haemoglobin levels in haemodialysis patients.

The epidemiology and control of anaemia among pre-ESRD patients with chronic kidney disease

Anaemia is a common condition among pre-end-stage renal disease (pre-ESRD) patients with chronic kidney disease (CKD). Indeed, data from clinical studies indicate that anaemia may be present in as many as two-thirds of such patients. Use of recombinant human erythropoietin (EPO) provides an effective means of correcting anaemia in CKD patients and helps to reduce the risk of renal disease progression and related problems. Unfortunately, EPO therapy is underutilized in these persons. Consequently, anaemia remains a major problem in the pre-ESRD CKD population. Evidence suggests that anaemia in the presence of CKD can lead to an increased risk of a number of adverse outcomes, including mortality, progression of kidney disease, coronary heart disease, stroke, hospitalization, and decreases in quality of life. Anaemia's association with these adverse outcomes suggests that effective treatment of anaemia in pre-ESRD CKD patients is of great importance and that substantial efforts should be made to ensure that these patients receive appropriate therapy to correct anaemia.

Anemia and mortality in hemodialysis patients: Accounting for morbidity and treatment variables updated over time

BACKGROUND

The objective of this study was to gain insight into the associations of anemia with mortality among maintenance hemodialysis (HD) patients and patient subgroups by an analysis that more comprehensively represents hemoglobin (Hb) level, morbidity, and treatment characteristics over time than was possible in prior observational studies.

METHODS

A cohort study was conducted among 5517 subjects in the American arm of the Dialysis Outcomes and Practice Patterns Study Phase I. We used proportional hazard analysis to model all-cause mortality as a function of Hb level measured 1, 3, and 6 months previously. Forty-five potentially confounding patient-level characteristics were considered, including demographics, comorbidities, and time-updated levels of erythropoietin and parenteral iron dosing, medical events, and laboratory and dialysis measures.

RESULTS

Compared to Hb 11 to <12 g/dL, subjects with Hb <11 g/dL had increased mortality [adjusted hazard ratios (95% confidence interval) in the 3-month-lagged model = 1.74 (1.24 to 2.43) for <9 g/dL, 1.25 (0.96 to 1.63) for 9 to <10 g/dL, and 1.22 (0.99 to 1.49) for 10 to <11 g/dL categories]. Mortality rates for subjects with Hb 12 to <13 g/dL and > or = 13 g/dL did not differ significantly from those with Hb 11 to <12 g/dL. The relationships between Hb and mortality varied modestly with changes in the time interval between Hb measurement and the time at risk for mortality, but did not vary according to ESRD vintage or health status indicators.

CONCLUSION

Our findings confirm the associations of Hb levels > or =11 g/dL with longer survival among maintenance HD patients, but show no additional survival advantage for patients with Hb levels > or =12 g/dL. Further investigation of the relationships among anemia, treatment of anemia, and survival is warranted.

Trends in Intravenous Iron Use Among Dialysis Patients in the United States (1994-2002)

BACKGROUND

Two new intravenous (IV) iron products, ferric gluconate and iron sucrose, recently were approved for use in the United States. We report trends in IV iron use in both incident (1994 to 2001) and prevalent (1994 to 2002) Medicare US dialysis patients.

METHODS

Included patients had Medicare as a primary payer. Recombinant human erythropoietin doses, IV iron use, and hemoglobin data were obtained from Medicare outpatient files. The most recent cohorts included 241,770 prevalent hemodialysis (HD) patients in 2002 and 11,744 incident HD patients in 2001.

RESULTS

For incident HD patients in the first 9 months of dialysis therapy, the percentage of patients administered IV iron increased sharply between 1994 and 1997 and then increased gradually between 1997 and 2001. In 2002, a total of 84.4% of HD and 19.3% of peritoneal dialysis (PD) patients were administered IV iron. Ferric gluconate use increased slowly in 2000, increased from 5.7% to 18.6% from December 2000 to January 2001, increased to 29.8% in April 2002, and was 23.3% in December 2002. Iron sucrose use increased to 26% by December 2002. The absolute monthly percentage of HD patients administered IV iron dextran decreased from 49.6% in January 2000 to 3.6% in December 2002.

CONCLUSION

In US patients with end-stage renal disease, IV iron use has increased, although slowly, from 1997 to 2002. Ferric gluconate and iron sucrose have become the predominant form of therapy. IV iron therapy was used in a much smaller percentage of PD compared with HD patients, and racial and geographic variability was observed.

Sodium ferric gluconate complex therapy in anemic children on hemodialysis

Pediatric patients with end-stage renal disease undergoing hemodialysis (HD) frequently develop anemia. Administration of recombinant human erythropoietin (rHuEPO) is effective in managing this anemia, although the additional demand for iron often results in iron deficiency. In adult patients undergoing HD, intravenous (IV) iron administration is known to replenish iron stores more effectively than oral iron administration. Nevertheless, IV iron supplementation is underutilized in pediatric patients, possibly because of unproved safety in this population. This international, multicenter study investigated the safety and efficacy of two dosing regimens (1.5 mg kg(-1) and 3.0 mg kg(-1)) of sodium ferric gluconate complex (SFGC) therapy, during eight consecutive HD sessions, in iron-deficient pediatric HD patients receiving concomitant rHuEPO therapy. Safety was evaluated in 66 patients and efficacy was evaluated in 56 patients. Significant increases from baseline were observed in both treatment groups 2 and 4 weeks after cessation of SFGC dosing for mean hemoglobin, hematocrit, transferrin saturation, serum ferritin, and reticulocyte hemoglobin content. Efficacy and safety profiles were comparable for 1.5 mg kg(-1) and 3.0 mg kg(-1) SFGC with no unexpected adverse events with either dose. Administration of SFGC was safe and efficacious in the pediatric HD population. Given the equivalent efficacy of the two doses, an initial dosing regimen of 1.5 mg kg(-1) is recommended for pediatric HD patients.

The effect of a change in epoetin alfa reimbursement policy on anemia outcomes in hemodialysis patients

In 1997, the Health Care Financing Administration Hematocrit Measurement Audit (HMA) program initiated use of a 3-month rolling average hematocrit (Hct) level for reimbursement of epoetin claims in hemodialysis patients, with denial of payment when this value exceeded 36.5%. This study evaluated the impact of the HMA program on anemia-related outcomes in hemodialysis patients. An observational, retrospective study of 987 hemodialysis patients from 11 dialysis centers in the United States was performed, collecting data between October 1996 and December 1997. Centers were selected from a pool of nearly all facilities in the United States, which during May 1997 satisfied one of two criteria: greater than 75% of patients at the facility had mean Hct level of > or =33% (Group A) or fewer than 50% of patients at the facility had mean Hct level of > or =33% (Group B). Each facility maintained its own anemia management practices without specific anemia management interventions as part of this study. Hct level, hemoglobin (Hb) level, and epoetin dose were analyzed to compare the pre-HMA period (October 1996 to May 1997) to the HMA period (June to December 1997) and/or for each of the five quarters of the study period. The primary study endpoint was the percentage of patients with Hct levels of > or =33% during each study quarter. The mean Hct level at baseline was 34% in Group A and 33.4% in Group B (p = 0.01). Hct levels, which were increasing before implementation of the HMA program, decreased during the HMA period (p < 0.001 and p = 0.013 in Groups A and B, respectively). The percentage of patients in Groups A and B with mean quarterly Hct levels of > or =33% decreased during the last quarter of the HMA implementation period compared to the quarter immediately preceding the start of the HMA program (p < 0.001 for both comparisons). Changes in Hb levels were similar to those seen in Hct levels. The mean epoetin dose administered decreased from 13,090 U/week at the start of the study to 11,884 U/week immediately before the HMA program took effect (p < 0.05). The HMA program adversely affected anemia treatment outcomes, regardless of whether dialysis units before HMA implementation had <50% of patients with a Hct level of > or =33% or had >75% of patients with a Hct level of > or =33%. The decline in mean weekly dose of epoetin was likely a result of withholding doses out of concern among providers about risk of reimbursement denial.

Protocolized anemia management with erythropoietin in hemodialysis patients: a randomized controlled trial

Treatment of the anemia of chronic renal failure with exogenous recombinant human erythropoietin (rHuEpo) is well established. The objective of this randomized clinical trial was to evaluate an anemia management team protocol in hemodialysis patients, using subcutaneous rHuEpo and intravenous iron. A total of 215 patients were randomized to either usual care or the protocol. The primary outcome was the proportion of patient hemoglobin (Hgb) values between 11.0 and 12.5 g/dl over the final 8 wk. The study was halted after 240 d because of an institutional change to intravenous rHuEpo. The proportion of Hgb values in the target range increased from 47.4% to 62.8% overall (P = 0.001); there was no difference between treatment groups. The proportion of baseline Hgb values between 11.0 and 12.5 g/dl increased from 44.6% in patients who had enrolled within the first 3 mo of study inception to 75.0% in those who started later (P = 0.017), suggesting a Hawthorne effect. A nonsignificant decrease in rHuEpo dose was observed in the protocol group; subgroup analysis in patients who were enrolled for at least 5 mo demonstrated a reduction in the rHuEpo dose of 2788 units/wk in the protocol group (P < 0.05), independent of intravenous iron dose. Multivariate analysis demonstrated that a higher transferrin saturation and albumin and protocol group assignment were associated with a lower final rHuEpo dose. This study demonstrated that a protocolized approach to anemia management in hemodialysis patients results in comparable Hgb levels and may reduce rHuEpo requirements, independent of iron use.

Inhibition of erythrocyte cation channels by erythropoietin

Recombinant human erythropoietin therapy is used to counteract anemia that is the result of renal insufficiency. It stimulates the formation of peripheral blood erythrocytes by inhibiting apoptosis of erythrocyte precursor cells. Mature erythrocytes have similarly been shown to undergo apoptosis. Hyperosmotic shock and Cl(-) removal activate a Ca(2+)-permeable, ethylisopropylamiloride-inhibitable cation channel. The subsequent increase of cytosolic Ca(2+) activates a scramblase that breaks down cell membrane phosphatidylserine asymmetry, leading to annexin binding. Studied was whether channel activity and erythrocyte cell death are regulated by erythropoietin. Scatchard plot analysis disclosed low-abundance, high-affinity binding of (125)I-erythropoietin to erythrocytes. Whole cell patch clamp experiments revealed significant inhibition of the ethylisopropylamiloride-sensitive current by 1 U/ml erythropoietin. Cl(-) removal triggered annexin binding, an effect abrogated by erythropoietin (1 U/ml) but not by GM-CSF (10 ng/ml). Osmotic shock (700 mOsm) stimulated annexin binding within 24 h in the majority of the erythrocytes, an effect blunted by erythropoietin (1 U/ml) but not by GM-CSF (10 ng/ml). In the nominal absence of Ca(2+), the effect of osmotic shock was blunted and the effect of erythropoietin abolished. In hemodialysis patients, intravenous administration of erythropoietin (50 IU/kg) within 4 h decreased the number of annexin binding circulating erythrocytes. Erythropoietin binds to erythrocytes and inhibits volume-sensitive erythrocyte cation channels and thus the breakdown of phosphatidylserine asymmetry after activation of this channel. The effect could prolong the erythrocyte lifespan and may contribute to the enhancement of the erythrocyte number during erythropoietin therapy in dialysis patients.

Management of anemia with quotidian hemodialysis

BACKGROUND

Most patients with end-stage renal disease have chronic anemia caused by inadequate erythropoietin (EPO) synthesis and require therapy with exogenous EPO to maintain recommended hematocrit and hemoglobin levels.

METHODS

The London Daily/Nocturnal Hemodialysis Study compared anemia control among patients on either short daily, long nocturnal, or conventional thrice-weekly hemodialysis (HD) therapy. Patients were administered iron, either orally (900 mg/d) or intravenously (50 to 125 mg every 1 to 4 weeks), to maintain serum ferritin levels at greater than 45 ng/mL (100 microg/L) or transferrin saturations greater than 20%. EPO was administered by subcutaneous injection at frequencies ranging from twice weekly to once every second week to maintain hemoglobin levels within the target range of 11 to 12 g/dL (110 to 120 g/L).

RESULTS

Both the daily HD and nocturnal HD study groups showed increased hemoglobin levels at later times compared with baseline levels, although only nocturnal HD patients had a statistically significant increase in hemoglobin levels at 18 months (11.94 g/dL [119.4 g/L] versus 10.95 g/dL [109.5 g/L] at baseline; P = 0.047). Both the daily HD and control groups showed a trend for decreased EPO dose requirements at later times compared with baseline, although these decreases were not statistically significant. The nocturnal HD group showed increased EPO dose requirements, although not statistically significant.

CONCLUSION

Quotidian HD is associated with an increased quantity of blood loss that can account for some of the increased requirements in EPO dose. Additional studies with larger numbers of patients are needed to fully elucidate the effects of quotidian HD on anemia.

Patterns of care for patients with chronic kidney disease in the United States: dying for improvement

The burden of chronic kidney disease can be assessed by multiple criteria that underscore the need for improved detection, treatment, and outcome monitoring. Several process measures for the care of advanced CKD patients are examined herein. Twenty seven and 11% of patients with CKD in National Health and Nutrition Examination Surveys (NHANES) III had BP <140/90 and 130/85, respectively. In addition to inadequate prescription of antihypertensive drugs, another confounder is poor diagnostic recognition of CKD. Recent surveys of incident Medicare-eligible ESRD patients observed severe anemia in a preponderance of patients; mean and median hematocrit values were 27.7% +/- 5.9 and 27.8%, respectively. Only 23 to 28% of these patients were prescribed epoetin alfa. Clinical practice guidelines recommend that <10% of maintenance hemodialysis patients should be chronically dialyzed using percutaneous catheters. A recent national survey of vascular access types among incident American hemodialysis patients found that 30%, 41%, and 29% were dialyzing through a catheter, prosthetic graft, and autologous fistula, respectively. Tunneled catheters are associated with a 39% annual increased risk of death. Based on pharmacokinetic assumptions about the minimum amount of solute clearance by hemodialysis needed for patient survival in ESRD, a GFR of 10.5 ml/min per 1.73 m(2) is needed. The mean GFR of incident ESRD patients in the United States was 9.5 ml/min per 1.73 m(2) in 2000. In addition to the wide international variability in modality treatment selection, geographic variability exists within the United States; <7 to >15% of the prevalent patients are treated by peritoneal dialysis across the country. Despite survival and quality-of-life benefits with transplantation, most eligible recipients in the United States have not been placed on a transplant waiting list 6 mo after beginning dialysis. Last, <40% of incident ESRD patients in the United States have received the recommended frequency of mammography, PAP examinations, or prostate-specific antigen (PSA) or HbA1c measurements. These deficiencies in care for patients with advanced CKD likely adversely influence the survival of US ESRD patients. Contemporary outcome information supports this contention. CKD patients referred to a nephrologist for the first time within 90 d of the start of dialysis have an approximately 40% to 60% increased risk of death during their first year of renal replacement therapy (RRT). Thirty-five percent of CKD patients are seen within 90 d of receiving RRT. In addition, if fewer than five nephrology visits occur, death risks are increased by 15%. These findings confirm the urgent need for improvement in healthcare delivery for CKD patient in the United States.

Development of an animal–human antibody complex for use as a control in ELISA

In order to provide the equivalent of a human anti-human protein antibody as positive control in ELISAs, a goat-human antibody complex was created using chemical cross-linking. The resulting hybrid complex had a larger molecular size on HPLC and SDS-PAGE. In ELISA, the goat-human complex bound to human antigen and was detectable by a secondary anti-human conjugate. The method to make the hybrid complex is simple, cost-effective and can be used to make human-like antibodies to many human proteins.

The cost-effectiveness of maintaining higher hemoglobin targets with erythropoietin in hemodialysis patients

BACKGROUND

There is uncertainty regarding the appropriate target hemoglobin level in hemodialysis patients treated with erythropoietin (EPO).

METHODS

We sought to determine the incremental cost-effectiveness of prescribing EPO to maintain different target hemoglobin levels, by incorporating the impact of EPO on health-related quality-of-life (HRQOL) issues and adopting the perspective of the health care purchaser. We evaluated the prescription of EPO to maintain target hemoglobin levels of 11.0 to 12.0, 12.0 to 12.5, and 14.0 g/dL, compared with 9.5 to 10.5 g/dL. Model outputs were quality-adjusted life expectancy and costs.

RESULTS

The base case analysis estimated intravenous EPO requirements to be 3523, 5078, 6097, and 9341 units three times per week to maintain targets of 9.5 to 10.5, 11.0 to 12.0, 12.0 to 12.5, and 14.0 g/dL, respectively. The cost per quality-adjusted life year (QALY) gained for the 11.0 to 12.0 g/dL target vs. 9.5 to 10.5 g/dL was $55,295 US. For the 12.0 to 12.5 g/dL target compared to 11.0 to 12.0 g/dL, and 14.0 g/dL target compared to 12.0 to 12.5 g/dL, the costs per QALY gained were $613,015 US and $828,215 US, respectively. In sensitivity analysis, clinically implausible reductions in hospitalization or EPO requirements associated with the two higher hemoglobin targets were required to make their incremental cost per QALY gained <$100,000 US.

CONCLUSION

Dosing intravenous EPO to achieve hemoglobin targets of 11.0 to 12.0 g/dL appears to be associated with incremental cost per QALY gained of $50,000 to $60,000, compared with a hemoglobin target of 9.5 to 10.5 g/dL. Aiming for hemoglobin targets in excess of 12.0 g/dL is associated with unfavorable cost-effectiveness ratios and should not be undertaken based on current data.

Iron metabolism in end stage renal failure: rationale for re-evaluation of parenteral iron therapy

PURPOSE OF REVIEW

In this article we will examine the basis for using chronic high dose parenteral iron therapy in dialysis patients.

RECENT FINDINGS

There are increasing data that dialysis patients fare better in many respects if they have higher hematocrit values although the real optimal hematocrit has not been defined. There is an increasing tendency to use parenteral iron to achieve this goal.

SUMMARY

Although parenteral iron achieves seemingly favourable short results, there are no data for its safety in the long term. On the contrary, there are reasons to suggest possible iron overload with chronic use.

Key concepts in biostatistics: using statistics to answer the question "is there a difference?"

Biostatistics seeks to answer the question "Is there a difference?" in the rate of a disease or characteristic among subgroups of patients. The goal of this article is to introduce and define measures used in epidemiology and discuss different types of analyses in clinical research with an emphasis on the concepts and implications of the analyses rather than the mathematics. The implications of the use of measures such as incidence and prevalence, as well as odds, risk, and hazards ratios may affect study conclusions. An understanding of the distinction between these summary measures is essential. The concepts of univariate and multivariate analyses, a discussion of what it means to control for potential confounders, and a description of statistical power and significance are also presented. These concepts are integral to the design and analysis of clinical studies. An understanding of their advantages and applications will enhance the reader's ability to understand and evaluate the literature.