Reversal of anemia by erythropoietin therapy retards the progression of chronic renal failure, especially in nondiabetic patients

Doubling of serum creatinine: is it appropriate as the endpoint for CKD? Proposal of a new surrogate endpoint based on the reciprocal of serum creatinine

BACKGROUND

The evaluation of the progression of renal insufficiency, or decline in glomerular filtration rate (GFR), has been approached more simply and precisely by converting measured serum creatinine value into the reciprocal of serum creatinine, estimated GFR, or other parameters. Doubling of serum creatinine (simple doubling) is conveniently used as a surrogate endpoint for progression of renal disease but is thought to be biased unfairly by the initial value of serum creatinine (Scr(Int)). We proposed the definite decline in the reciprocal of serum creatinine (2-4 doubling) as a surrogate endpoint, comparing simple doubling with this new endpoint to verify the effect of Scr(Int) on the endpoint.

METHODS

For the purpose of comparison between endpoints, 194 patients in a historical cohort of chronic glomerulonephritis were investigated. Kaplan-Meier survival analysis was performed with the composite endpoint of need for dialysis and either simple doubling or 2-4 doubling. Then, the distribution of Scr(Int) was compared between total patients and patients developing each endpoint.

RESULTS

The endpoint value of serum creatinine (Scr(End)) with 2-4 doubling was lower than that with simple doubling at Scr(Int) <2.00 mg/dl, and the difference of Scr(End) between simple doubling and 2-4 doubling was larger, as Scr(Int) became lower. In patients reaching simple doubling, Scr(Int) was higher than that of the total patients (1.66 vs. 1.07 mg/dl in median, respectively; p < 0.001). In patients reaching 2-4 doubling, there was no significant difference in Scr(Int).

CONCLUSION

Patients with low serum creatinine concentration at baseline had a tendency of prolonged development into simple doubling. In contrast, with 2-4 doubling, there was no bias of Scr(Int).

2008 Japanese Society for Dialysis Therapy: guidelines for renal anemia in chronic kidney disease

The Japanese Society for Dialysis Therapy (JSDT) guideline committee, chaired by Dr Y. Tsubakihara, presents the Japanese guidelines entitled "Guidelines for Renal Anemia in Chronic Kidney Disease." These guidelines replace the "2004 JSDT Guidelines for Renal Anemia in Chronic Hemodialysis Patients," and contain new, additional guidelines for peritoneal dialysis (PD), non-dialysis (ND), and pediatric chronic kidney disease (CKD) patients. Chapter 1 presents reference values for diagnosing anemia that are based on the most recent epidemiological data from the general Japanese population. In both men and women, hemoglobin (Hb) levels decrease along with an increase in age and the level for diagnosing anemia has been set at <13.5 g/dL in males and <11.5 g/dL in females. However, the guidelines explicitly state that the target Hb level in erythropoiesis stimulating agent (ESA) therapy is different to the anemia reference level. In addition, in defining renal anemia, the guidelines emphasize that the reduced production of erythropoietin (EPO) that is associated with renal disorders is the primary cause of renal anemia, and that renal anemia refers to a condition in which there is no increased production of EPO and serum EPO levels remain within the reference range for healthy individuals without anemia, irrespective of the glomerular filtration rate (GFR). In other words, renal anemia is clearly identified as an "endocrine disease." It is believed that defining renal anemia in this way will be extremely beneficial for ND patients exhibiting renal anemia despite having a high GFR. We have also emphasized that renal anemia may be treated not only with ESA therapy but also with appropriate iron supplementation and the improvement of anemia associated with chronic disease, which is associated with inflammation, and inadequate dialysis, another major cause of renal anemia. In Chapter 2, which discusses the target Hb levels in ESA therapy, the guidelines establish different target levels for hemodialysis (HD) patients than for PD and ND patients, for two reasons: (i) In Japanese HD patients, Hb levels following hemodialysis rise considerably above their previous levels because of ultrafiltration-induced hemoconcentration; and (ii) as noted in the 2004 guidelines, although 10 to 11 g/dL was optimal for long-term prognosis if the Hb level prior to the hemodialysis session in an HD patient had been established at the target level, it has been reported that, based on data accumulated on Japanese PD and ND patients, in patients without serious cardiovascular disease, higher levels have a cardiac or renal function protective effect, without any safety issues. Accordingly, the guidelines establish a target Hb level in PD and ND patients of 11 g/dL or more, and recommend 13 g/dL as the criterion for dose reduction/withdrawal. However, with the results of, for example, the CHOIR (Correction of Hemoglobin and Outcomes in Renal Insufficiency) study in mind, the guidelines establish an upper limit of 12 g/dL for patients with serious cardiovascular disease or patients for whom the attending physician determines high Hb levels would not be appropriate. Chapter 3 discusses the criteria for iron supplementation. The guidelines establish reference levels for iron supplementation in Japan that are lower than those established in the Western guidelines. This is because of concerns about long-term toxicity if the results of short-term studies conducted by Western manufacturers, in which an ESA cost-savings effect has been positioned as a primary endpoint, are too readily accepted. In other words, if the serum ferritin is <100 ng/mL and the transferrin saturation rate (TSAT) is <20%, then the criteria for iron supplementation will be met; if only one of these criteria is met, then iron supplementation should be considered unnecessary. Although there is a dearth of supporting evidence for these criteria, there are patients that have been surviving on hemodialysis in Japan for more than 40 years, and since there are approximately 20 000 patients who have been receiving hemodialysis for more than 20 years, which is a situation that is different from that in many other countries. As there are concerns about adverse reactions due to the overuse of iron preparations as well, we therefore adopted the expert opinion that evidence obtained from studies in which an ESA cost-savings effect had been positioned as the primary endpoint should not be accepted unquestioningly. In Chapter 4, which discusses ESA dosing regimens, and Chapter 5, which discusses poor response to ESAs, we gave priority to the usual doses that are listed in the package inserts of the ESAs that can be used in Japan. However, if the maximum dose of darbepoetin alfa that can currently be used in HD and PD patients were to be used, then the majority of poor responders would be rescued. Blood transfusions are discussed in Chapter 6. Blood transfusions are attributed to the difficulty of managing renal anemia not only in HD patients, but also in end-stage ND patients who respond poorly to ESAs. It is believed that the number of patients requiring transfusions could be reduced further if there were novel long-acting ESAs that could be used for ND patients. Chapter 7 discusses adverse reactions to ESA therapy. Of particular concern is the emergence and exacerbation of hypertension associated with rapid hematopoiesis due to ESA therapy. The treatment of renal anemia in pediatric CKD patients is discussed in Chapter 8; it is fundamentally the same as that in adults.

An economic evaluation of erythropoiesis-stimulating agents in CKD

BACKGROUND

The objective was to determine the cost-effectiveness of treating anemic patients with chronic kidney disease (CKD) with erythropoiesis-stimulating agents (ESAs) to a low (9-10.9 g/dL), intermediate (11-12 g/dL), or high (> 12 g/dL) hemoglobin level target compared with a strategy of managing anemia without ESAs.

STUDY DESIGN

Cost-utility analysis.

SETTING & PARTICIPANTS

Publicly funded health care system. Anemic patients with CKD, overall and stratified into dialysis-/non-dialysis-dependent subgroups.

MODEL, PERSPECTIVE, & TIMEFRAME

Decision analysis, health care payer, patient's lifetime.

MAIN OUTCOME

Cost per quality-adjusted life-year (QALY) gained.

RESULTS

For dialysis patients, compared with anemia management without ESAs, using ESAs to target a low hemoglobin level is associated with a cost per QALY of $96,270. Given a lack of direct trials comparing low and intermediate targets, significant uncertainty exists between these strategies. Treatment to a high hemoglobin target was always associated with worse clinical outcomes and higher costs compared with a low hemoglobin target. Results were similar in non-dialysis-dependent patients with CKD, with a cost per QALY for a low target compared with no ESA of $147,980.

LIMITATIONS

Given limitations in the available randomized controlled trials, we were able to model only 4 treatment strategies, balancing the need to consider relevant targets with the requirement for accurate estimates of clinical effect. We assumed that the efficacy of the different strategies would continue over a patient's lifetime.

CONCLUSIONS

Using ESAs to target a hemoglobin level > 12 g/dL is associated with worse clinical outcomes and significant additional cost compared with using ESAs to target lower hemoglobin levels (9-12 g/dL). Given a lack of studies comparing low (9-10.9 g/dL) and intermediate (11-12 g/dL) hemoglobin targets for clinical outcomes, including quality of life, the most cost-effective hemoglobin level target within the range of 9-12 g/dL is uncertain, although aiming for higher targets within this range will lead to higher costs.

Renal Protective Effects of Erythropoietin on Ischemic Reperfusion Injury

While the problem of organ shortage has not yet been solved, the number of patients who need to be treated with dialysis due to end-stage renal disease (ESRD) is increasing each year. With the aim of eliminating dialytic therapy as much as possible, the opportunities for organ donation from expansive criteria donor (ECD) or marginal donors due to cardiac death have been increasing. With the purpose of extracting organs in a state in which the function is preserved as much as possible, we reexamined the conditions of tissue disorders resulting from temporary ischemia of the organs as well as changes in tissue function and the effects on the preservation of renal function over time by using rat models in order to clinically utilize erythropoietin, which has inhibitory effects on ischemia-reperfusion disorder, as has been conventionally reported. With 8- to 9-week-old Wister male rats, after the right kidney had been resected under general anesthesia, the left renal artery was clamped to inhibit the blood flow for 45 min. At 30 min before inhibiting the blood flow and after releasing the inhibited blood flow, 100 U/kg of recombinant human erythropoietin (rhEPO) was administered via the inferior vena cava and the abdominal cavity, and then the tissues and blood samples were extracted at 6 and 24 h after the release. The renal tissue specimens were evaluated using H&E staining and TUNEL staining in order to observe differences in the expression of apoptosis as well as the renal function and changes in the emergence of active oxygen were investigated by using samples that had been obtained from drawn blood. Moreover, we examined the degree of renal dysfunction by means of neutrophil gelatinase-associated lipocalin (NGAL) in the spot urine samples. The changes in renal function, which were observed according to the serum creatinine level, showed that the renal function was preserved with a significant difference in the rhEPO administration group. The liver deviation enzymes, which had also shown increases in the serum as well as the occurrence of renal dysfunction, showed clear decreases in the serum, even though changes with a significant difference were not observed in the rhEPO administration group. The active oxygen did not show changes before and after ischemia-reperfusion nor changes due to the rhEPO administration. When examining the status of apoptosis in the tissues, apoptosis was shown to be inhibited due to the rhEPO administration. It is believed that the main preservation effects of rhEPO are the elimination of cytopathy/cell death, as derived from the resulting ischemic condition that extends to the target organ before ischemia occurs. In this examination, no direct effects of rhEPO administration on the emergence of active oxygen were observed. It is therefore suggested that there is a possibility of preserving the renal function in marginal donors with a longer agonal stage by effectively using rhEPO.

Risk factors for progression of chronic kidney disease

PURPOSE OF REVIEW

The present review provides an overview of the identified risk factors for chronic kidney disease (CKD) progression emphasizing the pediatric population.

RECENT FINDINGS

Over the past 10 years, there have been significant changes to our understanding and study of preterminal kidney failure. Recent refinements in the measurement of glomerular filtration rate and glomerular filtration rate estimating equations are important tools for identification and association of risk factors for CKD progression in children. In pediatric CKD, lower level of kidney function at presentation, higher levels of proteinuria, and hypertension are known markers for a more rapid decline in glomerular filtration rate. Anemia and other reported risk factors from the pregenomic era require further study and validation. Genome-wide association studies have identified genetic loci that have provided novel genetic risk factors for CKD progression.

SUMMARY

With cohort studies of children with CKD becoming mature, they have started to yield important refinements to the assessment of CKD progression. Although many of the traditional risk factors for renal progression will certainly be assessed, such cohorts will be important for evaluating novel risk factors identified by genome-wide studies.

Timely referral to the nephrologist: essential to optimizing patient outcomes

Annual mortality on renal replacement therapy is about 10% in Western Europe and reaches 20% in the United States. The reasons responsible for this excess mortality include among others advanced age, high prevalence of diabetes and comorbid conditions, susceptibility to infections, and cancer. An additional cause that should be considered is late referral to overall renal care and for renal replacement therapy. It has been demonstrated recently that early referral may provide many advantages for the patient, such as prevention of organ damage secondary to uremia and even delay the onset of end-stage renal disease. These benefits prompted numerous recommendations for timely referral, both for dialysis and for long-term renal follow-up. Despite available guidelines for nephrology referral the current practice is still suboptimal, resulting in delayed initiation of dialysis and clinical outcomes that are not ideal. There is an urgent need in the renal community to change the current practice of referral. Beyond the benefits for patients, society may also expect potential cost effectiveness from early renal care.

A randomized controlled study of weekly and biweekly dosing of epoetin alfa in CKD Patients with anemia

BACKGROUND AND OBJECTIVES

In clinical practice, physicians often use once-weekly (QW) and biweekly (Q2W) dosing of epoetin alfa to treat anemia in patients with chronic kidney disease (CKD). Although the literature supports this practice, previous studies were limited by short treatment duration, lack of randomization, or absence of the approved three times per week (TIW) dosing arm. This randomized trial evaluated extended dosing regimens of epoetin alfa, comparing QW and Q2W to TIW dosing in anemic CKD subjects. The primary objective was to show that treatment with epoetin alfa at QW and Q2W intervals was not inferior to TIW dosing.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

375 subjects with stage 3 to 4 CKD were randomized equally to the three groups and treated for 44 wk; to explore the impact of changing from TIW to QW administration on hemoglobin (Hb) control and adverse events, subjects on TIW switched to QW after 22 wk. The Hb was measured weekly, and the dose of epoetin alfa was adjusted to achieve and maintain an Hb level of 11.0 to 11.9 g/dl.

RESULTS

Both the QW and Q2W regimens met the primary efficacy endpoint. More subjects in the TIW group than in the QW and Q2W groups exceeded the Hb ceiling. Adverse events were similar across treatment groups and consistent with the morbidities of CKD patients.

CONCLUSIONS

Administration of epoetin alfa at QW and Q2W intervals are potential alternatives to TIW dosing for the treatment of anemia in stage 3 to 4 CKD subjects.

Exploration of anaemia as a progression factor in African Americans with cardiovascular disease

BACKGROUND

Despite the higher incidence of end-stage renal disease (ESRD) among African Americans, whites in the USA have a higher prevalence of chronic kidney disease. This may be due, in part, to faster progression to ESRD among African Americans. Anaemia is associated with a risk of kidney disease progression and is more prevalent among African Americans. The purpose of this study is to determine if anaemia is associated with progression to ESRD differently according to race.

METHODS

A retrospective cohort study of Cooperative Cardiovascular Project data for 87 693 Medicare beneficiaries >or=65 years old and ESRD free admitted to 4047 hospitals with acute myocardial infarction between February 1994 and June 1995 was conducted. Follow-up was collected through June 2004 for ESRD and mortality.

RESULTS

Among 87 693 patients, 7.0% were African Americans and 50.1% females. African Americans had a higher prevalence of anaemia than whites (40.2% versus 26.7%, respectively; P < 0.001). Lower haematocrit was associated with higher ESRD rates after adjustment, and the association of haematocrit with ESRD did not vary according to race (P = 0.19). This association was strongest at the lowest baseline kidney function (GFR <15) with hazard ratios increasing 7-fold as haematocrit decreased from >or= 42% to <28%.

CONCLUSIONS

In a nationally representative sample of patients with cardiovascular disease, anaemia was associated equally among African Americans and whites with an increased risk of ESRD.

Emerging therapies for chronic kidney disease: what is their role?

The prevalence of chronic kidney disease (CKD) is increasing worldwide. The best therapies currently available focus on the control of blood pressure and optimization of renin-angiotensin-aldosterone system blockade. Currently available agents are only partially effective against hard end points such as the development of end-stage renal disease and are not discussed in this Review. Many other agents have been shown to reduce proteinuria and delay progression in animal models of CKD. Some of these agents, including tranilast, sulodexide, thiazolidinediones, pentoxifylline, and inhibitors of advanced glycation end-products and protein kinase C, have been tested to a limited extent in humans. A small number of randomized controlled human trials of these agents have used surrogate markers such as proteinuria as end points rather than hard end points such as end-stage renal disease or doubling of serum creatinine level. Emerging therapies that specifically target and reverse pathological hallmarks of CKD such as inflammation, fibrosis and atrophy are needed to reduce the burden of this chronic disease and its associated morbidity. This Review examines the evidence for emerging pharmacological strategies for slowing the progression of CKD.

Erythropoietin and renoprotection

In the haematopoietic system, the principal function of erythropoietin (EPO) is the regulation of RBC production. Consequently, following the cloning of the EPO gene, recombinant human EPO (rHuEPO) forms have been widely used for treatment of anaemia in chronic kidney disease and chemotherapy-induced anaemia in cancer patients. However, a steadily growing body of evidence indicates that the therapeutic benefits of rHuEPO could be far beyond the correction of anaemia. Several articles have been recently published on the tissue-protective, nonhaematological effects of rHuEPO that prevent ischaemia-induced tissue damage in several organs including the kidney.In this review, we focus on nonhaematological effects of rHuEPO in various experimental settings of acute and chronic kidney injury. Because this tissue-protective action of rHuEPO is not the result of correction of anaemia-related tissue hypoxia, we will also discuss potential molecular pathways involved. Finally, we will review the current literature on clinical studies with rHuEPO or analogous substances and progression of chronic kidney disease, and propose possible clinical renoprotective strategies.

What is so bad about a hemoglobin level of 12 to 13 g/dL for chronic kidney disease patients anyway?

Randomized controlled trials (RCTs) clearly indicate a possible cardiovascular morbidity and mortality risk when deliberately targeting a normal hemoglobin (Hb) concentration of 13 to 15 g/dL. By contrast, observational studies point to greater hospitalization and mortality at Hb levels <11 g/dL. There are no direct data to help us determine where, within this broad range, the optimal Hb lies. In RCTs and observational studies, significant confounding from the interrelationships of anemia and epoetin resistance occurs in patients with a serious illness. Patients with comorbidities such as malnutrition and inflammatory processes are more resistant to epoetin and, invariably, require greater cumulative epoetin doses. The effect of a higher erythropoiesis-stimulating agent (ESA) dose on increasing mortality has been noted repeatedly in post hoc analyses of RCTs. It is therefore too simplistic to solely attribute the outcomes achieved in RCTs to "target Hb." We discuss various mechanisms for potential harm at higher Hb levels as opposed to those that may be obtained from higher epoetin doses. For the individual patient, the therapeutic decision should center on what Hb is most appropriate at a "safe" ESA dose. Consequently, an Hb of 12 to 13 g/dL may be totally appropriate in some patient populations.

Anemia and cardiovascular risk in the patient with kidney disease

Patients with chronic kidney disease (CKD) often experience anemia, which causes fatigue and diminished quality of life. In addition, anemia in CKD has been associated with increased risk for cardiovascular events and left ventricular hypertrophy. To the extent that anemia plays a causal role in these relationships, treatment with erythropoiesis-stimulating agents (ESAs) could potentially help improve outcomes. To date, however, results from interventional studies have been disappointing in this regard. This article reviews the relationship between anemia in CKD and cardiovascular risk and explores current knowledge on ESA treatment.

Diabetic nephropathy--what are the unmet needs?

In this pandemic of diabetes and obesity, Asia will have the highest number of affected people with the greatest increase in the young-to-middle aged group. Asian patients have increased risk for diabetic kidney disease which may be compounded by low grade infection, obesity and genetic factors. In these subjects, the onset of albuminuria and diabetic kidney disease causes further perturbation of metabolic milieu with increased oxidative stress, anaemia and vascular calcification which interact to markedly increase the risk of cardiovascular disease. Despite receiving optimal care to control blood pressure and metabolic risk factors as well as inhibition of the renin-angiotensin system in a clinical trial setting, there is a considerable residual risk for cardio-renal complications in patients with diabetic kidney disease. Control of obesity and low grade inflammation as well as correction of anaemia may represent areas where novel strategies can be developed and tested to curb this rising global burden of cardio-renal complications.

Evidence-based guide to slowing the progression of early renal insufficiency

Early renal insufficiency (ERI), defined as a calculated or measured glomerular filtration rate (GFR) between 30 and 60 mL/min per 1.73 m2, is present in more than 10% of the adult Australian population. This pernicious condition is frequently unrecognised, progressive and accompanied by multiple associated comorbidities, including hypertension, renal osteodystrophy, anaemia, sleep apnoea, cardiovascular disease, hyperparathyroidism and malnutrition. Several treatments have been suggested to retard GFR decline in ERI, including blood pressure reduction, angiotensin-converting enzyme inhibition, angiotensin receptor antagonism, calcium channel blockade, cholesterol reduction, smoking cessation, erythropoietin therapy, dietary protein restriction, intensive glycaemic control and early intensive multidisciplinary patient education within a renal unit. In addition, specific interventions have been reported to be renoprotective in atherosclerotic renal artery stenosis, diabetic nephropathy, lupus nephritis and certain forms of primary glomerulonephritis. The present paper reviews the available published randomised controlled clinical trials and meta-analyses supporting (or refuting) a role for each of these therapeutic manoeuvres.

Slowing chronic kidney disease progression: results of prospective clinical trials in adults

Chronic kidney disease is generally thought to be a progressive disorder regardless of etiology. Over the past 15 years, investigations into the mechanisms of disease progression and treatment designed to slow or halt disease progression have been conducted, largely in the adult kidney disease population. Intervention trials have demonstrated that lowering blood pressure in hypertensive patients and administration of drugs that block the renin-angiotensin aldosterone system are effective at slowing kidney disease progression, including diabetes, hypertension, and various glomerular diseases. In addition, novel strategies including anemia therapy with erythropoietin-stimulating agents have been conducted to determine whether treatment of this common complication of kidney disease can stabilize kidney function. Whereas substantial success has been achieved in more common forms of adult kidney disease such as diabetes and hypertension, slowing progression of some immune-mediated glomerular disease such as lupus nephritis and immunoglobulin A (IgA) nephropathy remain a great challenge. Moreover, there is no proven strategy, including multifactorial interventions, that clearly halts progressive chronic kidney disease that has been studied prospectively in a large-scale, long-term trial. The purpose of this review is to discuss these trials, as they form the underpinnings for current clinical practice guidelines in adults with chronic kidney disease.

Left ventricular dysfunction in the haemodialysis population

Cardiovascular disease in the haemodialysis population continues to contribute to mortality and morbidity. Disorders of left ventricular geometry and function are highly prevalent and lead to increased mortality in this highly vulnerable population. Left ventricular dysfunction (LVDys), often as a result of hypertension, ischaemic cardiac disease or dilated cardiomyopathy, has not been uniformly defined in the literature making diagnosis and therapy problematic. Although routinely available, screening by echocardiography is critically volume dependent and prone to underestimation in left ventricular ejection fraction. Few randomized control trials are available to guide management with the majority of evidence requiring extrapolation from the non-dialysis population. Beyond medication, interventional cardiac procedures such as implantable cardiac defibrillator implantation and cardiac resynchronization therapy show promise. Conversion to alternative dialysis modalities such as peritoneal dialysis, short-daily or nocturnal dialysis have been attempted and are actively being explored.

Economic burden of chronic kidney disease

OBJECTIVES

To define the cost of care and evaluate interventions associated with improving outcomes and delaying the progression of chronic kidney disease (CKD).

METHODS

Using the PubMed database, a systematic review of the literature was conducted describing (i) the cost of care associated with treating earlier stages of CKD, and (ii) the role of early referral, erythropoiesis-stimulating proteins and anti-hypertensive agents in improving clinical outcomes and reducing the cost of CKD.

RESULTS

The higher costs associated with treatment of the CKD population are largely due to higher rates and duration of comorbidity-driven hospitalizations. Studies suggest that early referral to a nephrologist, use of erythropoiesis-stimulating proteins and anti-hypertensive agents may be associated with better outcomes and lower costs. In some instances, however, higher target haemoglobin levels could have harmful effects in CKD patients.

CONCLUSION

The substantial costs incurred during earlier stages of CKD increase markedly during the transition to renal replacement and remain elevated thereafter. An increase in awareness among health care providers may result in more timely interventions. More proactive management, in turn, can lead to improved clinical and economic outcomes through the slowing of disease progression and prevention of comorbidities.

Anemia of Chronic Kidney Disease

Chronic kidney disease may result in complete kidney failure and contribute to many other health issues. Anemia is a logical consequence of the disease because the kidneys are the primary source of erythropoietin, the hormone that acts to stimulate red blood cell production in the bone marrow. All patients with chronic kidney disease are at risk for anemia, and treating anemia is extremely important to their health and well-being. Preventing or reversing the effects of anemia on the heart may decrease morbidity and mortality and improve quality of life. Many patients fail to receive treatment for anemia before requiring renal replacement therapy for end-stage renal disease. Pharmacists can play a vital role in screening, evaluating, designing proper treatment regimens, and monitoring patients with anemia of chronic kidney disease. Current recommendations regarding anemia are reviewed, including evaluation, pharmacotherapeutic agents, monitoring parameters, and goals of therapy.

Darbepoetin alfa for anemia in chronic kidney disease

Anemia of chronic kidney disease (CKD) is common, yet it is often under-recognized and undertreated, with serious adverse consequences. It is highly responsive to treatment with erythropoiesis-stimulating agents (ESAs). Darbepoetin alfa is a hyperglycosylated ESA that has a lower affinity to the erythropoietin receptor but a longer half-life than recombinant human erythropoietin, irrespective of administration by a subcutaneous or intravenous route. Owing to its pharmacokinetic characteristics, darbepoetin alfa has been used in extended dosing intervals ranging from once every week to once every 4 weeks in CKD patients on dialysis, as well as in CKD patients not on dialysis. Darbepoetin alfa has been shown to be safe and effective in clinical trials. The safety profile of darbepoetin alfa is similar to that of recombinant human erythropoietin. While target hemoglobin levels in CKD anemia remain debatable, treatment of anemia with ESAs has the proven benefits of reducing transfusions and improving quality of life. Darbepoetin alfa has the potential to simplify the treatment of CKD anemia with many advantages, including infrequent dosing, improved patient convenience and compliance, and decreased healthcare resource utilization.

The optimal hemoglobin in dialysis patients- a critical review

The introduction of recombinant human erythropoietin treatment has been one of the most important advances in the treatment of dialysis patients and others with chronic kidney disease (CKD). Treatment of CKD anemia has been shown to reduce the need for blood transfusions and to improve quality of life. However, the target hemoglobin level in treating patients is currently controversial. This is because of the recent publication of two randomized controlled studies in nondialysis CKD patients, the CREATE and CHOIR studies, as well as an accompanying meta-analysis. These studies demonstrate increase risk for death and cardiovascular complications when aiming for a hemoglobin (Hgb) level of >12 g/dl. In light of this new data, the National Kidney Foundation Kidney Disease Outcomes Quality Initiative anemia guidelines are being revised. The Food and Drug Administration has issued a Black Box warning and indicated that hemoglobin levels do not exceed 12 g/dl. While observational data suggest a benefit for higher hemoglobin levels, these studies have limitations because of their retrospective design and the potential effect of confounding factors. Hence, reliance on observational studies to guide CKD anemia treatment is a potentially flawed and hazardous process. In this editorial we propose that the current literature does not support an upper Hgb target above 12 g/dl. We also suggest that the current reimbursement system for erythropoiesis stimulating agent treatment potentially encourages unsafe overtreatment.

Erythropoietin: physiology and molecular mechanisms

Erythropoietin, the primary regulator of erythropoiesis, is produced by the kidney and levels vary inversely with oxygen availability. Hypoxia-inducible factor-1 (HIF-1), a major transcriptional regulator of several hypoxia-sensitive genes, including erythropoietin, is functionally deactivated by oxygen in a reaction catalyzed by prolyl hydroxylase. Erythropoietin acts by binding to a specific trans-membrane dimeric receptor which has been found in erythroid and non-erythroid cell types. The interaction between erythropoietin and its receptor ultimately leads to conformational change and phosphorylation of the receptor and expression of genes coding for proteins that are anti-apoptotic. Development of erythropoietin stimulating agents is an area of active research. To date, research has focused on activating the erythropoietin receptor, prevention of HIF-1 inactivation, and gene therapy. Even with biologically effective therapies, defining appropriate hemoglobin targets remains challenging. For example, despite decades of clinical trials, target hemoglobin levels in chronic kidney disease remain uncertain, as hemoglobin targets above 13 g/dl have been associated with both benefit (quality of life) and harm (cardiovascular events).

Potential roles of erythropoietin in the management of anaemia and other complications diabetes

Erythropoietin (EPO) is a haematopoietic cytokine, mainly generated in the renal cortex, and its secretion and action is impaired in chronic kidney disease (CKD). Early renal damage in diabetes mellitus (DM) is usually not detected because diabetes-induced nephron hypertrophy maintains glomerular filtration rate (GFR) and an elevated plasma creatinine concentration is a relatively late manifestation of diabetic nephropathy. However, anaemia occurs more frequently in subjects with DM when compared with those with non-DM renal disease. While reduced production and a blunted response to EPO occurs in DM with early renal damage, other factors including chronic inflammation, autonomic neuropathy and iron deficiency are also important. Although recombinant human erythropoietin (rhEPO) has been an effective therapeutic agent in CKD anaemia, it appears to be more effective in patients with DM, even in earlier stages. Nevertheless, patients with DM are also more likely to be iron deficient, a barrier to effective rhEPO therapy. The effect of treatment on the reliability of haemoglobin A(1c) as an index of glycaemic control must be remembered. It is proposed that anaemia and its causes must be important components of care in subjects with early diabetic renal damage.

Anemia as a risk factor for chronic kidney disease

Chronic kidney disease (CKD) is an important and leading cause of end-stage renal disease (ESRD) and moreover, plays a role in the morbidity and mortality due to cardiovascular disease, infection, and cancer. Anemia develops during the early stages of CKD and is common in patients with ESRD. Anemia is an important cause of left ventricular hypertrophy and congestive heart failure. Correction of anemia by erthyropoiesis-stimulating agent (ESA) has been shown to improve survival in patients with congestive heart failure. Anemia is counted as one of the non-conventional risk factors associated with CKD. Hypoxia is one of the common mechanisms of CKD progression. Treatment by ESA is expected to improve quality of life, survival, and prevent the CKD progression. Several clinical studies have shown the beneficial effects of anemia correction on renal outcomes. However, recent prospective trials both in ESRD and in CKD stages 3 and 4 failed to confirm the beneficial effects of correcting anemia on survival. Similarly, treatment of other risk factors such as hyperlipidemia by statin showed no improvement in the survival of dialysis patients. Given the high prevalence of anemia in ESRD and untoward effects of anemia in CKD stages 3 and 4, appropriate and timely intervention on renal anemia using ESA is required for practicing nephrologists and others involved in the care of high-risk population. Lessons from the recent studies are to correct renal anemia (hemoglobin <10 g/dl not hemoglobin > or =13 g/dl). Early intervention for renal anemia is a part of the treatment option in the prevention clinic. In this study, clinical significance of anemia management in patients with CKD is discussed.

Erythropoiesis-stimulating agents: past and future

Renal anemia is a well-recognized complication of chronic kidney disease (CKD), and the deficiency of erythropoietin (EPO) is the primary cause. Observational population-based studies continue to demonstrate the association of low hemoglobin with adverse outcomes, and renal failure, cardiac failure, and anemia all may interact to cause or worsen each other, the so-called cardio-renal anemia syndrome. Treatment of anemia can be successfully achieved with the use of erythropoiesis-stimulating agents (ESAs). From a mechanistic point of view, however, the therapeutic benefits of ESA could be far beyond the correction of anemia. ESA modulates a broad array of cellular processes that include progenitor stem cell development, cellular integrity, and angiogenesis. A pleiotropic effect of EPO has been shown in the central nervous system, the cardiovascular system, and the kidney. While recent results of randomized controlled trials have established that there is little support for normalizing hemoglobin in CKD patients, the results of these studies do not negate renoprotective effects of EPO. A large number of patients with CKD will benefit from early recognition and appropriate correction of anemia with ESA.

Use of erythropoiesis-stimulating agents in patients with anemia of chronic kidney disease: overcoming the pharmacological and pharmacoeconomic limitations of existing therapies

Stage 3 chronic kidney disease (CKD), which is characterized by a glomerular filtration rate of 30 to 60 mL/min/1.73 m2 (reference range, 90-200 mL/min/1.73m2 for a 20-year-old, with a decrease of 4 mL/min per decade), affects approximately 8 million people in the United States. Anemia is common in patients with stage 3 CKD and, if not corrected, contributes to a poor quality of life. Erythropoiesis-stimulating agents (ESAs), introduced almost 2 decades ago, have replaced transfusions as first-line therapy for anemia. This review summarizes the current understanding of the role of ESAs in the primary care of patients with anemia of CKD and discusses pharmacological and pharmacoeconomic issues raised by recent data. Relevant studies in the English language were identified by searching the MEDLINE database (1987-2006). Two ESAs are currently available in the United States, epoetin alfa and darbepoetin alfa. More frequent dosing with epoetin alfa is recommended by the labeled administration guidelines because it has a shorter half-life than darbepoetin alfa. Clinical experience also supports extended dosing intervals for both these ESAs. Use of ESAs in the management of anemia of CKD is associated with improved quality of life, increased survival, and decreased progression of renal failure. Some evidence suggests that ESAs have a cardioprotective effect. However, correction of anemia to hemoglobin levels greater than 12 g/dL (to convert to g/L, multiply by 10) appears to increase the risk of adverse cardiac outcomes and progression of kidney disease in some patients. The prescription of ESAs in the primary care setting requires an understanding of the accepted use of these agents, the associated pharmacoeconomic challenges, and the potential risks. This review considers the need to balance effective ESA dosing intervals against the potential risks of treatment.

Mechanism of increased mortality risk with erythropoietin treatment to higher hemoglobin targets

Recent randomized, controlled trials indicate that there is a strong trend for increased risk for death or adverse composite outcomes with erythropoiesis-stimulating agent treatment in kidney disease to hemoglobin targets higher than those currently recommended. The failure of these trials to find a benefit of higher hemoglobin is in stark contrast to findings from large, observational, population-based studies that continue to demonstrate the association of low hemoglobin with adverse outcomes. The mechanisms for the adverse effect of higher hemoglobin targets that are seen in the randomized, controlled trials are poorly understood. This review explores hypotheses involving (1) the effect of achieved hemoglobin itself, (2) the role of erythropoiesis-stimulating agent treatment, (3) the use of iron supplementation, (4) increased blood pressure, and (5) erythropoiesis-stimulating agent hyporesponsiveness. Because the causal pathway has yet to be determined, further research is strongly encouraged. Clinical practice, however, should avoid erythropoiesis-stimulating agent treatment to higher hemoglobin targets, particularly in those with significant cardiovascular morbidity and those who require disproportionately high dosages of erythropoietin-stimulating agents to achieve recommended hemoglobin levels.

Treating anemia of chronic kidney disease in the primary care setting: cardiovascular outcomes and management recommendations

Anemia is an underrecognized but characteristic feature of chronic kidney disease (CKD), associated with significant cardiovascular morbidity, hospitalization, and mortality. Since their inception nearly two decades ago, erythropoiesis-stimulating agents (ESAs) have revolutionized the care of patients with renal anemia, and their use has been associated with improved quality of life and reduced hospitalizations, inpatient costs, and mortality. Hemoglobin targets >/=13 g/dL have been linked with adverse events in recent randomized trials, raising concerns over the proper hemoglobin range for ESA treatment. This review appraises observational and randomized studies of the outcomes of erythropoietic treatment and offers recommendations for managing renal anemia in the primary care setting.

Darbepoetin alfa protects podocytes from apoptosis in vitro and in vivo

Detachment or apoptosis of podocytes leads to proteinuria and glomerulosclerosis. There are no current interventions for diabetic or non-diabetic glomerular diseases specifically preventing podocyte apoptosis. Binding of erythropoiesis stimulating proteins (ESPs) to receptors on non-hematopoietic cells has been shown to have anti-apoptotic effects in vitro, in vivo, and in preliminary human studies. Recently, erythropoietin receptors were identified on podocytes; therefore, we tested effects of darbepoetin alfa in preventing podocyte apoptosis. Cultured immortalized mouse podocytes were treated with low-dose ultraviolet-C (uv-C) irradiation to induce apoptosis in the absence or presence of darbepoetin alfa. Apoptosis was quantified by Hoechst staining and by caspase 3 cleavage assessed by Western blots. Pretreatment with darbepoetin alfa significantly reduced podocyte apoptosis with this effect involving intact Janus family protein kinase-2 (JAK2) and AKT signaling pathways. Additionally, darbepoetin alfa was found protective against transforming growth factor-beta1 but not puromycin aminonucleoside induced apoptosis. Mice with anti-glomerular antibody induced glomerulonephritis had significantly less proteinuria, glomerulosclerosis, and podocyte apoptosis when treated with darbepoetin alfa. Our studies show that treatment of progressive renal diseases characterized by podocyte apoptosis with ESPs may be beneficial in slowing progression of chronic kidney disease.

Administration of exogenous erythropoietin beta affects lipid peroxidation and serum paraoxonase-1 activity and concentration in predialysis patients with chronic renal disease and anaemia

1. Patients with advanced chronic renal disease and anaemia have decreased serum paraoxonase-1 (PON1) activity and an increased degree of oxidative stress compared with normal subjects. The present study investigated the effects of treatment of anaemia with exogenous recombinant erythropoietin (EPO) beta and iron on levels of antibodies against oxidized low-density lipoproteins (ox-LDL), as well as on serum PON1 activity and concentration, in predialysis patients with chronic renal disease. 2. Forty-nine patients with chronic renal failure and haemoglobin (Hb) < 11 g/dL were treated over a period of 6 months with EPObeta (80-120 U/kg per week, s.c.) and variable doses of iron. Selected biochemical variables were determined before and after treatment. 3. Treatment with EPObeta and iron was associated with a significant increase in mean (+/-SD) blood Hb concentration compared with pretreatment values (12.8 +/- 1.5 vs 9.9 +/- 0.6 g/dL, respectively; P < 0.001). The average dose of EPObeta was 6160 +/- 3000 U/week. After 6 months of treatment, compared with pretreatment values, the median levels (95% confidence intervals) of antibodies against ox-LDL were decreased (17.5 (10.6-24.4) vs 24.8 (11.5-38.1) U/mL, respectively; P < 0.001), serum PON1 activity was slightly but significantly increased (123.6 (76.1-343.6) vs 101.0 (50.0-332.5) U/L, respectively; P = 0.016) and the concentration of PON1 was significantly decreased (37.3 (11.8-76.2) vs 46.7 (24.6-98.0) mg/L, respectively; P < 0.001). There were no significant changes in total cholesterol, triglycerides or cholesterol fraction concentrations before and after treatment. 4. We suggest that EPObeta and iron treatment of anaemia promotes significant changes in serum PON1 activity and concentration and has a beneficial effect on oxidative stress in predialysis patients with chronic renal disease.

Exceeding hemoglobin target levels in US hemodialysis patients receiving epoetin, 1999 to 2002

Despite emerging concerns that exceeding anemia targets with erythropoiesis stimulating agents may be risky for hemodialysis patients, the magnitude of and risk factors for the problem have received little attention, particularly regarding year-to-year comparisons. We studied monthly hemoglobin and epoetin levels in 41,101 patients aged at least 65 years who initiated hemodialysis between 1999 and 2002, with upper targets defined by hemoglobin levels of 120 and 130 g/L, respectively. While baseline hemoglobin values and epoetin doses rose from year to year, their rates of change during follow-up declined (p<0.0001). Similar patterns were seen after reaching hemoglobin levels of 110 g/L; comparing 1999 to 2002, the proportions reaching 120 and 130 g/L in the ensuing 9 months increased from 90% to 96% (p<0.0001) and from 56% to 69%, respectively (p<0.0001). Multivariate analysis showed that, while more recent years of dialysis inception and initial epoetin dose were associated with all 3 outcomes, higher baseline hemoglobin levels were associated with reaching levels of 110 and 120 g/L, but not 130 g/L. Exceeding hemoglobin level targets has become widespread in the United States and is associated with changes in epoetin dosing practices.

The new FDA label for erythropoietin treatment: how does it affect hemoglobin target?

The erythropoietin analogs have been an important advance for the treatment of the anemia of kidney disease, resulting in reduced need for blood transfusion and improved quality of life. Recent studies, however, have indicated risks associated with targeting higher levels of hemoglobin (Hb). As a result, in March 2007, the US Food and Drug Administration (FDA) substantially changed prescribing information for these drugs to alert clinicians to these risks. In this review, we consider the recent literature, the change in FDA warnings, and new National Kidney Foundation Anemia Guidelines. Suggestions for new Hb targets during erythropoiesis-stimulating agent treatment are presented.

Podocyte protection by darbepoetin: preservation of the cytoskeleton and nephrin expression

Podocyte injury is a significant contributor to proteinuria and glomerulosclerosis. Recent studies have shown a renoprotective effect of erythropoietin (EPO) during ischemic kidney disease. In this study, we examine mechanisms by which a long acting recombinant EPO analog, darbepoetin, may confer renoprotection in the puromycin aminonucleoside-induced model of nephrotic syndrome. Darbepoetin decreased the proteinuria of rats treated with puromycin. This protective effect was correlated with the immunohistochemical disappearance of the podocyte injury markers desmin and the immune costimulator molecule B7.1 with the reappearance of nephrin expression in the slit diaphragm. Podocyte foot process retraction and effacement along with actin filament rearrangement, determined by electron microscopy, were all reversed by darbepoetin treatment. The protective effects were confirmed in puromycin-induced nephrotic rats that had been hemodiluted to normal hematocrit levels. Furthermore, puromycin treatment of rat podocytes in culture caused actin cytoskeletal reorganization along with deranged nephrin distribution. All these effects in vitro were reversed by darbepoetin. Our study demonstrates that darbepoetin treatment ameliorates podocyte injury and decreases proteinuria by a direct effect on podocytes. This may be accomplished by maintenance of the actin cytoskeleton and nephrin expression.