Dose of erythropoiesis-stimulating agents and adverse outcomes in CKD: a metaregression analysis

Target-based Anemia Management with Erythropoiesis Stimulating Agents (Risks and Benefits Relearned) and Iron (Still More to Learn)

The FDA first licensed erythropoiesis stimulating agents (ESA) for use in patients with ESRD in 1989. Hemoglobin targets for treatment with ESAs were established at the outset on the basis of descriptive pre-ESA literature and Phase I-III data in patients with ESRD. Postrelease literature in ESA-treated patients accumulating over time initially supported improvement in indices of both cardiovascular and other organ function as well as quality of life with therapy. Recommended treatment targets for hemoglobin would evolve further in the United States from four iterations of evidence- and opinion-based practice guidelines appearing between 1997 and 2007. Several randomized, controlled trials published from 1998 to 2009 examined normalization and near-normalization of hemoglobin in patients with both ESRD and CKD; they raised fundamental questions as to the safety of robust correction of anemia. These findings, taken together with subsequent actions of the FDA in ESA labeling and CMS's quality expectations for hemoglobin in payment for dialysis treatments, would result in a comprehensive reassessment of the hemoglobin targets in ESA therapy. A marked decrease in both national ESA utilization and hemoglobin attainment has ensued as a result. This discussion addresses the history of the striking changes in enthusiasm for hemoglobin-targeted anemia therapy from 1989 to the present, and similarly examines the evolution of ferritin-targeted iron administration, which has followed different-and markedly slower-historical development.

Erythropoiesis stimulating agents and reno-protection: a meta-analysis

Background

Erythropoiesis stimulating agents (ESAs) were proposed to enhance survival of renal tissues through direct effects via activation of EPO receptors on renal cells resulting in reduced cell apoptosis, or indirect effects via increased oxygen delivery due to increased numbers of Hb containing red blood cells. Thus through several mechanisms there may be benefit of ESA administration on kidney disease progression and kidney function in renal patients. However conflicting ESA reno-protection outcomes have been reported in both pre-clinical animal studies and human clinical trials. To better understand the potential beneficial effects of ESAs on renal-patients, meta-analyses of clinical trials is needed.

Methods

Literature searches and manual searches of references lists from published studies were performed. Controlled trials that included ESA treatment on renal patients with relevant renal endpoints were selected.

Results

Thirty two ESA controlled trials in 3 categories of intervention were identified. These included 7 trials with patients who had a high likelihood of AKI, 7 trials with kidney transplant patients and 18 anemia correction trials with chronic kidney disease (predialysis) patients. There was a trend toward improvement in renal outcomes in the ESA treated arm of AKI and transplant trials, but none reached statistical significance. In 12 of the anemia correction trials, meta-analyses showed no difference in renal outcomes with the anemia correction but both arms received some ESA treatment making it difficult to assess effects of ESA treatment alone. However, in 6 trials the low Hb arm received no ESAs and meta-analysis also showed no difference in renal outcomes, consistent with no benefit of ESA/ Hb increase.

Conclusions

Most ESA trials were small with modest event rates. While trends tended to favor the ESA treatment arm, these meta-analyses showed no reduction of incidence of AKI, no reduction in DGF or improvement in 1-year graft survival after renal transplantation and no significant delay in progression of CKD. These results do not support significant clinical reno-protection by ESAs.

The Safety of Erythropoiesis-Stimulating Agents for the Treatment of Anemia Resulting from Chronic Kidney Disease

Chronic kidney disease (CKD) anemia treatment was revolutionized in the late 1980s with the introduction of recombinant human erythropoietin. This and related erythropoiesis-stimulating agents (ESAs) greatly benefited patients by decreasing debilitating symptoms, improving their quality of life, and freeing them from dependence on blood transfusions with their associated complications such as infections, sensitization impeding transplantation, and secondary iron overload. However, even in the initial studies, untoward effects were noted in patients receiving ESAs, including worsening hypertension, seizures, and dialysis access clotting. Later, increased mortality, malignancy progression and even stroke were reported in renal patients. This review focuses on the safety issues of ESAs in CKD patients.

Hypertension in CKD Pregnancy: a Question of Cause and Effect (Cause or Effect? This Is the Question)

Chronic kidney disease (CKD) is increasingly encountered in pregnancy, and hypertension is frequently concomitant. In pregnancy, the prevalence of CKD is estimated to be about 3%, while the prevalence of chronic hypertension is about 5-8%. The prevalence of hypertension and CKD in pregnancy is unknown. Both are independently related to adverse pregnancy outcomes, and the clinical picture merges with pregnancy-induced hypertension and preeclampsia. Precise risk quantification is not available, but risks linked to CKD stage, hypertension, and proteinuria are probably multiplicative, each at least doubling the rates of preterm and early preterm delivery, small for gestational age babies, and related outcomes. Differential diagnosis (based upon utero-placental flows, fetal growth, and supported by serum biomarkers) is important for clinical management. In the absence of guidelines for hypertension in CKD pregnancies, the ideal blood pressure goal has not been established; we support a tailored approach, depending on compliance, baseline control, and CKD stages, with strict blood pressure monitoring. The choice of antihypertensive drugs and the use of diuretics and of erythropoiesis-stimulating agents (ESAs) are still open questions which only future studies may clarify.

An Evidence-Based Approach to Conducting Systematic Reviews on CKD

With the growing need to integrate best evidence to inform clinical care, systematic reviews have continued to flourish. Although this type of review is integral to the synthesis of evidence-based information, systematic reviews are often conducted omitting well-established processes that ensure the validity and replicability of the study; elements of which are integral based on standards developed by the Cochrane Collaboration and the National Academy of Medicine. This review article will share best practices associated with conducting systematic reviews on the topic of CKD using an 8-step process and an evidence-based approach to retrieving and abstracting data. Optimal methods for conducting systematic review searching will be described, including development of appropriate search strategies and utilization of varied resources including databases, grey literature, primary journals, and handsearching. Processes and tools to improve research teams' coordination and efficiency, including integration of systematic review protocols and sophisticated software to streamline data management, will be investigated. In addition to recommended strategies for surveying and synthesizing CKD literature, techniques for maneuvering the complex field of Nephrology will also be explored.

Negative Relationship between Erythropoietin Dose and Blood Lead Level in Patients Undergoing Maintenance Hemodialysis

The adverse effects of increased blood lead levels have been well discussed. Several antioxidant agents have been reported to offer protection from lead toxicity and to reduce blood lead levels (BLL). Given that erythropoietin (EPO) also has antioxidant properties, the aim of this cross-sectional study was to assess the role of EPO and other clinical variables on BLL in hemodialysis (HD) patients. We recruited 931 maintenance hemodialysis (MHD) patients who had undergone HD for at least 6 months and who had ever received blood lead level (BLL) study. Use of erythropoiesis-stimulating agents followed the The National Kidney Foundation Kidney Disease Outcomes Quality Initiative (NKF KDOQI) Clinical Practice Guideline. We estimated demographic, hematological, nutritional, inflammatory, biochemical, and dialysis-related data based on this study. In the group with EPO, 7% had high BLL. In the group without EPO, 22% had high BLL. From the stepwise liner regression, urban areas, hemodialysis duration, and clearance of urea (KT/V_urea) were positively associated with log BLL. In contrast, diabetes (DM), and monthly EPO dose were negatively associated with log BLL. This study showed that EPO dose might be negatively associated with blood lead levels in patients on maintenance hemodialysis.

The Cost-Effectiveness of Anemia Treatment for Persons with Chronic Kidney Disease

BACKGROUND

Although major guidelines uniformly recommend iron supplementation and erythropoietin stimulating agents (ESAs) for managing chronic anemia in persons with chronic kidney disease (CKD), there are differences in the recommended hemoglobin (Hb) treatment target and no guidelines consider the costs or cost-effectiveness of treatment. In this study, we explored the most cost-effective Hb target for anemia treatment in persons with CKD stages 3-4.

METHODS AND FINDINGS

The CKD Health Policy Model was populated with a synthetic cohort of persons over age 30 with prevalent CKD stages 3-4 (i.e., not on dialysis) and anemia created from the 1999-2010 National Health and Nutrition Examination Survey. Incremental cost-effectiveness ratios (ICERs), computed as incremental cost divided by incremental quality adjusted life years (QALYs), were assessed for Hb targets of 10 g/dl to 13 g/dl at 0.5 g/dl increments. Targeting a Hb of 10 g/dl resulted in an ICER of $32,111 compared with no treatment and targeting a Hb of 10.5 g/dl resulted in an ICER of $32,475 compared with a Hb target of 10 g/dl. QALYs increased to 4.63 for a Hb target of 10 g/dl and to 4.75 for a target of 10.5 g/dl or 11 g/dl. Any treatment target above 11 g/dl increased medical costs and decreased QALYs.

CONCLUSIONS

In persons over age 30 with CKD stages 3-4, anemia treatment is most cost-effective when targeting a Hb level of 10.5 g/dl. This study provides important information for framing guidelines related to treatment of anemia in persons with CKD.

Erythropoietin Dose and Mortality in Hemodialysis Patients: Marginal Structural Model to Examine Causality

It has been previously reported that a higher erythropoiesis stimulating agent (ESA) dose in hemodialysis patients is associated with adverse outcomes including mortality; however the causal relationship between ESA and mortality is still hotly debated. We hypothesize ESA dose indeed exhibits a direct linear relationship with mortality in models of association implementing the use of a marginal structural model (MSM), which controls for time-varying confounding and examines causality in the ESA dose-mortality relationship. We conducted a retrospective cohort study of 128 598 adult hemodialysis patients over a 5-year follow-up period to evaluate the association between weekly ESA (epoetin-α) dose and mortality risk. A MSM was used to account for baseline and time-varying covariates especially laboratory measures including hemoglobin level and markers of malnutrition-inflammation status. There was a dose-dependent positive association between weekly epoetin-α doses ≥18 000 U/week and mortality risk. Compared to ESA dose of <6 000 U/week, adjusted odds ratios (95% confidence interval) were 1.02 (0.94-1.10), 1.08 (1.00-1.18), 1.17 (1.06-1.28), 1.27 (1.15-1.41), and 1.52 (1.37-1.69) for ESA dose of 6 000 to <12 000, 12 000 to <18 000, 18 000 to <24 000, 24 000 to <30 000, and ≥30 000 U/week, respectively. High ESA dose may be causally associated with excessive mortality, which is supportive of guidelines which advocate for conservative management of ESA dosing regimen in hemodialysis patients.

An overview on safety issues related to erythropoiesis-stimulating agents for the treatment of anaemia in patients with chronic kidney disease

INTRODUCTION

Erythropoiesis stimulating agents (ESA) are effective drugs, which have been used for decades in patients with chronic kidney disease (CKD) with few side effects. More recently, concern has been raised around their safety, from higher cardiovascular and thrombosis risk to cancer progression and increased mortality.

AREAS COVERED

We made a literature search on PubMed looking for adverse effects of ESA in CKD patients. The topics covered are cardiovascular adverse events, thrombosis, increased mortality, hypertension, cancer progression, diabetic retinopathy, pure red cell aplasia and anaphylactic reactions.

EXPERT OPINION

Concerns around ESA therapy have questioned treatment indications in high-risk CKD patients (those with cancer, diabetes and cardiovascular comorbidities). A more cautious approach has then prevailed. In our opinion, intermediate Hb values (Hb 10-12 g/dl) should be aimed with ESA therapy, being more cautious in high-risk patients. As a consequence, IV iron is administered more frequently. However, excessive iron use may cause iron overload and in rare cases severe anaphylactic reactions. There are expectations of new erythropoietic agents, such as those manipulating the hypoxia-inducible transcription factors (HIF) system. Differing from ESAs, they stimulate the production of endogenous EPO, avoiding over-physiological plasmatic levels.

Regulation of platelet count by erythropoiesis-stimulating agents - iron axis in hemodialysis patients

Higher doses of erythropoiesis-stimulating agents (ESAs) contribute to atherothrombotic cardiovascular disease in hemodialysis (HD) patients. Thrombocytosis is associated with increased mortality in ESA-treated HD patients. We investigated variables affecting platelet count and its variability (platelet count increment [Δplatelet count]) in HD patients. This retrospective longitudinal and observational study of HD outpatients was carried out over 3 years. The outcome was independent determinants of platelet count and Δplatelet count, which were associated with iron indices, ESA dose, and C-reactive protein. In univariate regression analysis, V-shaped relationship was observed between platelet count and transferrin saturation (TSAT), ferritin, serum iron, and hemoglobin (Hb) with the bottom of 0.21, 330 ng/mL, 49 µg/dL, and 10.3 g/dL, respectively. Mixed-effect multivariate regression analysis revealed that TSAT (inversely), Hb ≤10.3 g/dL (inversely), C-reactive protein, and ESA dose were independently associated with platelet count. Δplatelet count was independently and inversely correlated with ΔTSAT and directly correlated with Δferritin. TSAT was independently and inversely associated with ESA dose. ESA dose was directly correlated with iron dose and inversely correlated with TSAT, ferritin ≤330 ng/mL, and Hb ≤10.3 g/dL. ESA dose and TSAT were correlated in determining platelet count and Δplatelet count. Targets of iron indices that reflect iron supply sufficient to avoid platelet count increment and variability may be >21% of TSAT and 300 ng/mL of serum ferritin for appropriate ESA therapy in HD patients.

Associations between hematopoietic growth factors and risks of venous thromboembolism, stroke, ischemic heart disease and myelodysplastic syndrome: findings from a large population-based cohort of women with breast cancer

PURPOSE

To determine the risk of venous thromboembolism (VTE), stroke, ischemic heart disease, and myelodysplastic syndrome (MDS) in association with the receipt of colony-stimulating factors (CSFs) and/or erythropoiesis-stimulating agents (ESAs) in women with breast cancer.

METHODS

We studied 77,233 women with breast cancer aged ≥65 in 1992-2009 from the Surveillance, Epidemiology, and End Results-Medicare linked data with up to 19 years of follow-up.

RESULTS

Incidence of VTE increased from 9 cases in women receiving no chemotherapy and no CSFs/ESAs to 22.79 cases per 1,000 person-years in those receiving chemotherapy with CSFs and ESAs. Women with chemotherapy who received both CSFs and ESAs (adjusted hazard ratio and 95 % confidence interval 2.01, 1.80-2.25) or received ESAs without CSFs (2.03, 1.74-2.36) were twice as likely to develop VTE than those receiving no chemotherapy and no CSFs/ESAs, whereas those receiving CSF alone without ESA were 64 % more likely to have VTE (1.64, 1.45-1.85). Risk of MDS was significantly increased by fivefold in patients receiving ESA following chemotherapy.

CONCLUSIONS

Receipts of CSFs and ESAs were significantly associated with an increased risk of VTE in women with breast cancer. Use of ESAs was significantly associated with substantially increased risks of MDS. These findings support those of previous studies.

Impaired renal endothelial nitric oxide synthase and reticulocyte production as modulators of hypertension induced by rHuEPO in the rat

Our aim was to study the effect of a broad range of recombinant human erythropoietin (rHuEPO) doses on hematological and biochemical parameters, blood pressure (BP), renal function and damage in the rat, focusing on endothelial nitric oxide synthase (eNOS) and hypoxia-inducible factors (HIFs). Male Wistar rats were divided in 5 groups receiving different doses of rHuEPO (100, 200, 400 and 600IU/kg body weight (BW)/week) and saline solution (control), during 3weeks. Blood and 24h urine were collected to perform hematological and biochemical analysis. BP was measured by the tail-cuff method. Kidney tissue was collected to mRNA and protein expression assays and to characterize renal lesions. A dose-dependent increase in red blood cells count, hematocrit and hemoglobin levels was found with rHuEPO therapy, in rHuEPO200, rHuEPO400 and rHuEPO600 groups. Increased reticulocyte count was found in rHuEPO400 and rHuEPO600 groups. BP raised in all groups receiving rHuEPO. The rHuEPO200 and rHuEPO600 groups presented increased kidney protein levels of HIF2α, a reduction in kidney protein levels of eNOS, and the highest grade of vascular and tubular renal lesions. Our study showed that rHuEPO-induced hypertension is present before significant hematological changes occur and, therefore, might involve direct (renal) and indirect (hematological) effects, which varies according to the dose used. The presence of renal hypoxia reduces eNOS activity. Excessive erythrocytosis increases blood hyperviscosity, which can be modulated by an increase in reticulocytes. Hypertension leads to early renal damage without alterations in traditional markers of renal function, thus underestimating the serious adverse effects and risks.

Effect of intravenous iron on outcomes of acute kidney injury

BACKGROUND

Little is known about benefit versus risk in treating iron deficiency anemia with intravenous (IV) iron in patients with acute kidney injury (AKI). Concerns about adverse outcomes may dissuade use and could contribute to greater use of red blood cell (RBC) transfusion.

STUDY DESIGN AND METHODS

We performed a retrospective case-control study of patients with AKI who received IV iron (cases) compared to those with AKI without IV iron (controls).

RESULTS

We identified 67 cases and 67 controls matched for age, stage of chronic kidney disease, and severity of anemia (hemoglobin [Hb], 7.7 ± 0.1 mg/dL vs. 7.5 ± 0.1 mg/dL; p = 0.47). Cases tended to be sicker with longer length of stay (27 + 4 days vs. 15 + 1.3 days; p = 0.003) and more intensive care unit days (13 + 2 days vs. 5 + 1 days; p = 0.003), more often with diagnosis of sepsis and greater number of antibiotics used (2.7 ± 0.3 vs. 1.8 ± 0.2; p = 0.02). Sepsis and AKI preceded use of IV iron. Despite greater illness severity, there was no difference in dialysis (38.8% vs. 34.3%; p = 0.59), mortality (24% vs. 21%; p = 0.679), or severity and/or recovery of AKI. Discharge Hb was similar (9.0 ± 0.1 mg/dL vs. 9.1 ± 0.1 mg/dL; p = 0.47). IV iron was used later in the stay and hence the cases also had more RBC transfusions.

CONCLUSIONS

We were unable to find any adverse consequences of use of IV iron when used to treat anemia in patients with AKI in regard to recovery of AKI or mortality even in patients with a diagnosis of sepsis. Consideration of preemptive use of IV iron in AKI with severe anemia is warranted to determine if this would reduce RBC transfusion.

Effectiveness of Darbepoetin Alfa for Chemotherapy-induced Anemia When Initiated at Hemoglobin ≤10 g/dL

PURPOSE

Limited data are available to describe the effectiveness of darbepoetin alfa (DA) in terms of hemoglobin (Hb) and transfusion outcomes when initiated at Hb ≤10 g/dL (the threshold specified in the summary of prescribing characteristics). We assessed DA, initiated according to current labeling (Hb ≤10 g/dL), in chemotherapy-induced anemia (CIA).

METHODS

Data for patients with cancer and CIA who initiated DA at Hb ≤10 g/dL were extracted from a database of Amgen-sponsored trials. A comparative analysis was limited to randomized, controlled trials in patients treated with DA or control (placebo/best supportive care). Data for the DA arm(s) of randomized, multiple-arm, or prospective, single-arm trials were also extracted (DA-only analysis; non-front-loaded studies only). Outcomes included Hb increase ≥1 g/dL or ≥2 g/dL during the first 12 weeks of treatment. Crude and Kaplan-Meier proportions of patients who experienced each outcome and time (days) to each outcome were summarized by treatment arm. Meta-analysis (fixed-effects inverse-variance method) was performed to compare outcomes for DA with control.

FINDINGS

The comparative analysis included 4 studies (2 in lung cancer, 1 in lymphoproliferative disease, and 1 in non-myeloid malignancy: DA, n = 261; control, n = 273). The DA-only analysis included 15 studies (n = 3768). In comparative analyses, more patients who received DA than placebo achieved Hb increase of ≥1 g/dL (fixed-effects hazard ratio [HR] = 2.07; 95% CI, 1.62-2.63) or ≥2 g/dL (HR = 2.91; 95% CI, 2.09-4.06). Median times to ≥1 g/dL or ≥2 g/dL increase were 43 or 78 days for DA (not evaluable for placebo). Transfusions were less common in patients who received DA (HR = 0.58; 95% CI, 0.44-0.77). Addition of 2 dose-finding studies did not change the findings of the main comparative analysis. Results were similar in the DA-only analyses.

IMPLICATIONS

This is the first patient-level meta-analysis, to our knowledge, to evaluate the efficacy in terms of Hb response of DA treatment when initiated according to current product labeling in patients with CIA. Limitations include the small number of studies and patients eligible for inclusion in the comparative analyses and the absence of non-Amgen trials of DA. The results of the comparative analysis confirm that DA is more effective than placebo at increasing serum Hb levels and at reducing the need for transfusion in patients with CIA when treatment is initiated at Hb ≤10 g/dL, as per current product labeling.

Drug therapies to delay the progression of chronic kidney disease

Chronic kidney disease (CKD) is associated with significant morbidity and mortality, impacted not alone by progression to end-stage kidney disease, but also by the high associated incidence of cardiovascular events and related mortality. Despite our current understanding of the pathogenesis of CKD and the treatments available, the reported incidence of CKD continues to rise worldwide, and is often referred to as the silent public healthcare epidemic. The significant cost to patient wellbeing and to the economy of managing the later stages of CKD have prompted efforts to develop interventions to delay the development and progression of this syndrome. In this article, we review established and novel agents that may aid in delaying the progression of CKD and improve patient outcomes.

The Korean Clinical Research Center for End-Stage Renal Disease Study Validates the Association of Hemoglobin and Erythropoiesis-Stimulating Agent Dose with Mortality in Hemodialysis Patients

Background

Anemia is an important risk factor for mortality in hemodialysis (HD) patients. However, higher hemoglobin (Hb) is not necessarily better, as seen in several studies. This study aimed to validate the clinical use of an Hb target of 10–11 g/dL in Korean HD patients.

Methods

A total of 1,276 HD patients from the Clinical Research Center (CRC) for End-Stage Renal Disease (ESRD) were investigated in a prospective observational study. Cox proportional hazard analysis was conducted for each category of time-dependent Hb level and erythropoiesis-stimulating agent (ESA) dose, with subgroup analysis stratified by age and diabetes status.

Results

Using a reference Hb level of 10–11 g/dL, the hazard ratios (HRs) of death were 5.12 (95% confidence interval [CI], 2.62–10.02, P <0.05) for Hb level <9.0 g/dL, and 2.03 (CI, 1.16–3.69, P <0.05) for Hb level 9.0–10.0 g/dL, after adjustment for multiple clinical variables. However, an Hb level ≥11 g/dL was not associated with decreased mortality risk. In an adjusted model categorized by Hb and ESA dose, the risk of death at an Hb level <10 g/dL and a higher dose of ESA (≥126 U/kg/week) had an HR of 2.25 (CI, 1.03–4.92, P <0.05), as compared to Hb level 10–11 g/dL and a lower dose of ESA. In subgroup analysis, those older than 65 years or who were diabetic had greater risk for mortality only in Hb category <9.0 g/dL. However, there was no significant interaction between age or diabetes status and Hb.

Conclusion

Using CRC-ESRD data, we validated the association between Hb and ESA dose and mortality in Korean HD patients. The clinical practice target of an Hb of 10–11 g/dL before the new KDIGO guideline era seems reasonable considering its survival benefit in HD patients.

Efficiency of Original versus Generic Intravenous Iron Formulations in Patients on Haemodialysis

AIMS

The appropriate use of intravenous (i.v.) iron is essential to minimise the requirements for erythropoiesis-stimulating agents (ESAs). The clinical efficacy of generic i.v. iron compared to the original formulation is controversial. We evaluated the changes that were induced after switching from a generic i.v. iron to an original formulation in a stable, prevalent haemodialysis (HD) population.

METHODS

A total of 342 patients were included, and the follow-up period was 56 weeks for each formulation. Anaemia parameters and doses of ESA and i.v. iron were prospectively recorded before and after the switch from generic to original i.v. iron.

RESULTS

To maintain the same haemoglobin (Hb) levels after switching from the generic to the original formulation, the requirements for i.v. iron doses were reduced by 34.3% (from 52.8±33.9 to 34.7±31.8 mg/week, p<0.001), and the ESA doses were also decreased by 12.5% (from 30.6±23.6 to 27±21 μg/week, p<0.001). The erythropoietin resistance index declined from 8.4±7.7 to 7.4±6.7 IU/kg/week/g/dl after the switch from the generic to the original drug (p = 0.001). After the switch, the transferrin saturation ratio (TSAT) and serum ferritin levels rose by 6.8% (p<0.001) and 12.4% (p = 0.001), respectively. The mortality rate was similar for both periods.

CONCLUSIONS

The iron and ESA requirements are lower with the original i.v. iron compared to the generic drug. In addition, the uses of the original formulation results in higher ferritin and TSAT levels despite the lower dose of i.v. iron. Further studies are necessary to analyse the adverse effects of higher i.v. iron dosages.

The cost effectiveness of erythropoietin-stimulating agents for treating anemia in patients on dialysis: a systematic review

BACKGROUND

Anemia is a common complication associated with kidney failure and is marked by poor health and increased risk of morbidity and mortality. There are ongoing concerns with the use of Erythropoietin Stimulating Agents (ESAs) to treat anemia in patients with kidney failure on dialysis. Questions as to their benefits, harms and overall effect on quality of life are still relevant today. Our objective was to systematically review studies evaluating the cost-effectiveness of ESAs in patients with kidney failure on dialysis.

METHODS

We performed a systematic review of studies determining the cost-effectiveness of ESAs in adult patients on dialysis. Databases, including PubMed, EMBASE, and Cochrane Database of Systematic Reviews, were searched from their establishment until June 2013. Studies that reported an incremental cost-effectiveness ratio of hemoglobin correction strategies based on ESA treatments in comparison to red blood cell transfusions, lower hemoglobin targets, or no ESA treatment were included.

RESULTS

Seven studies met inclusion criteria. Reported cost/quality-adjusted life-year (QALY) ratios ranged from USD 931-677,749/QALY across five studies comparing ESAs to red blood cell transfusions. There was heterogeneity in results when considering higher hemoglobin targets, with studies finding higher targets to be both dominant and dominated. Mortality, hospitalization, and utility estimates were major drivers.

CONCLUSIONS

There is substantial variability in the estimates of the cost-effectiveness of using ESAs in the dialysis population. New models incorporating recent meta-analyses for estimates of utility, mortality, and hospitalization changes would allow for a more comprehensive answer to this question.

Clinical outcomes with use of erythropoiesis stimulating agents in patients with the HeartMate II left ventricular assist device

OBJECTIVES

This study evaluated clinical outcomes associated with erythropoiesis stimulating agent (ESA) use in left ventricular assist devices (LVAD)-supported patients.

BACKGROUND

Use of ESAs in patients with LVADs may minimize blood transfusions and decrease allosensitization. ESAs increase thrombotic events, which is concerning because LVADs are sensitive to pump thrombosis (PT).

METHODS

We retrospectively reviewed 221 patients at our center who received a HeartMate II (Thoratec Corp., Pleasanton, California) LVAD between January 1, 2009 and June 6, 2013. Patients were divided into those who received ESAs during index admission (n = 121) and those who did not (n = 100). Suspected PT was defined as evidence of thrombus in the LVAD or severe hemolysis (lactate dehydrogenase >1,000 mg/dl or plasma-free hemoglobin >40 mg/dl). Outcomes were compared between cohorts using inverse probability-weighted analyses.

RESULTS

During a mean follow-up of 14.2 ± 11.9 months, suspected PT occurred in 37 patients (ESA 23%, no ESA 12%; p =0.03). The ESA cohort received ESAs 13.9 ± 60.9 days after LVAD implantation. At 180 days, event-free rates for suspected PT were ESA 78.6% versus no ESA 94.5% (p < 0.001). ESA use had higher rates of suspected PT (hazard ratio [HR]: 2.35; 95% confidence interval [CI]: 1.38 to 4.00; p = 0.002). For every 100-unit increase in cumulative ESA dosage, the hazard of suspected PT increased by 10% (HR: 1.10; 95% CI: 1.04 to 1.16; p < 0.001). After inverse probability weighting, ESA use was associated with a significantly higher rate of all-cause mortality (HR: 1.62; 95% CI: 1.12 to 2.33; p = 0.01).

CONCLUSIONS

ESA use in LVAD patients is associated with higher rates of suspected PT.

Responsiveness to erythropoiesis-stimulating agents in chronic kidney disease: does geography matter?

Management of renal anemia in the large and at-risk population of non-dialysis chronic kidney disease (CKD) patients is a critical issue. In particular, definition of the optimal hemoglobin (Hb) target for therapy is controversial but highly warranted by physicians and patients worldwide. Recently, international clinical practice guidelines have recommended delayed initiation of erythropoiesis-stimulating agents (ESA) and lower Hb target levels during maintenance therapy. However, geographical differences in terms of ESA dose needed to achieve a given Hb value can be evidenced, with US patients showing higher prevalence of ESA resistance. On the other hand, non-US patients are often maintained in a higher Hb range by means of low ESA doses. This critical point has never been addressed. Nevertheless, outside of the US, translating the restrictive recommendations of new guidelines, which are essentially based on trials in US patients, can lead to negative effects, such as an increased need for a blood transfusion, and worsening of quality of life. In this article we provide a reappraisal of current recommendations on anemia management in non-dialysis CKD in light of the geographical differences in individual responsiveness to ESA.

Erythropoiesis-stimulating agents: dose and mortality risk

Hypo-responsiveness to erythropoiesis-stimulating agents (ESAs) has been associated with increased mortality in end-stage renal disease patients. It is not clear if this effect is related to the elevated ESAs dosage for targeting hemoglobin levels or underlying morbid conditions that lead to ESA resistance. We retrospectively evaluated from 2008 to death or December 2011, 28 consecutive incident hemodialysis patients. We identified 2 cohort of patients based on their mean annual ESAs dosage. The correlation between data was evaluated with the Spearman's rho test. Kaplan-Meier curves were generated to assess survival in subjects with high and low ESAs mean dose. Median ESAs dosage, used as a cutoff point between patients at high and low ESAs dose, was at 11.000 IU/week for epoetin alfa and beta, 55 mcg/week for darbopoietin, and 220 mcg/month for cera. Mean hemoglobin (Hb) level was 10.58 ± 0.13 g/dL. Of 28 patients, during follow-up, 6 (21,4%) died of all causes. High-dose ESA therapy was associated with increased all-cause mortality (P = .047). Moreover, there was a negative correlation between ESAs dose and Hb levels (rho = -0.825; P < .001). Higher ESAs dose for the treatment of anemia in incident hemodialysis patients was associated with higher mortality risk. ESAs and Hb serum levels were inversely correlated with mortality. Together, these findings suggest that ESAs dosage and Hb level may play a role through an independent manner or an interactive effect that adversely affects mortality.

Phosphorus binding with ferric citrate is associated with fewer hospitalizations and reduced hospitalization costs

BACKGROUND

Ferric citrate (FC) is a new phosphorus binder shown to increase serum iron stores while reducing intravenous iron and erythropoiesis-stimulating agent usage. Such reductions could lower hospitalization rates and associated costs.

METHODS

Hospitalizations during a Phase III trial were compared between FC and active control (AC). Hospitalization costs were estimated using the 2013 US Renal Data System Annual Data Report.

RESULTS

34.6% of FC patients were hospitalized at least once versus 45.6% of the AC group (risk reduction 24.2%; p = 0.02). There were 181 unique hospitalizations in the FC group versus 239 in the AC group, for a difference of 58 hospitalizations. Total potential savings was US$ 867,622 in hospitalization costs in the FC group. If the hospitalization reduction in our study was applied to the general end-stage renal disease population, this could translate into a savings of US$ 3002/patient/year.

CONCLUSIONS

Patients receiving FC experienced fewer hospitalizations with the potential for significant savings.

Iron supplementation and mortality in incident dialysis patients: an observational study

BACKGROUND

Studies on the association between iron supplementation and mortality in dialysis patients are rare and conflicting.

METHODS

In our observational single-center cohort study (INVOR study) we prospectively studied 235 incident dialysis patients. Time-dependent Cox proportional hazards models using all measured laboratory values for up to 7.6 years were applied to study the association between iron supplementation and all-cause mortality, cardiovascular and sepsis-related mortality. Furthermore, the time-dependent association of ferritin levels with mortality in patients with normal C-reactive protein (CRP) levels (<0.5 mg/dL) and elevated CRP levels (≧0.5 mg/dL) was evaluated by using non-linear P-splines to allow flexible modeling of the association.

RESULTS

One hundred and ninety-one (81.3%) patients received intravenous iron, 13 (5.5%) patients oral iron, whereas 31 (13.2%) patients were never supplemented with iron throughout the observation period. Eighty-two (35%) patients died during a median follow-up of 34 months, 38 patients due to cardiovascular events and 21 patients from sepsis. Baseline CRP levels were not different between patients with and without iron supplementation. However, baseline serum ferritin levels were lower in patients receiving iron during follow up (median 93 vs 251 ng/mL, p<0.001). Iron supplementation was associated with a significantly reduced all-cause mortality [HR (95%CI): 0.22 (0.08-0.58); p = 0.002] and a reduced cardiovascular and sepsis-related mortality [HR (95%CI): 0.31 (0.09-1.04); p = 0.06]. Increasing ferritin concentrations in patients with normal CRP were associated with a decreasing mortality, whereas in patients with elevated CRP values ferritin levels>800 ng/mL were linked with increased mortality.

CONCLUSIONS

Iron supplementation is associated with reduced all-cause mortality in incident dialysis patients. While serum ferritin levels up to 800 ng/mL appear to be safe, higher ferritin levels are associated with increased mortality in the setting of concomitant inflammation.

Mimicking hypoxia to treat anemia: HIF-stabilizer BAY 85-3934 (Molidustat) stimulates erythropoietin production without hypertensive effects

Oxygen sensing by hypoxia-inducible factor prolyl hydroxylases (HIF-PHs) is the dominant regulatory mechanism of erythropoietin (EPO) expression. In chronic kidney disease (CKD), impaired EPO expression causes anemia, which can be treated by supplementation with recombinant human EPO (rhEPO). However, treatment can result in rhEPO levels greatly exceeding the normal physiological range for endogenous EPO, and there is evidence that this contributes to hypertension in patients with CKD. Mimicking hypoxia by inhibiting HIF-PHs, thereby stabilizing HIF, is a novel treatment concept for restoring endogenous EPO production. HIF stabilization by oral administration of the HIF-PH inhibitor BAY 85-3934 (molidustat) resulted in dose-dependent production of EPO in healthy Wistar rats and cynomolgus monkeys. In repeat oral dosing of BAY 85-3934, hemoglobin levels were increased compared with animals that received vehicle, while endogenous EPO remained within the normal physiological range. BAY 85-3934 therapy was also effective in the treatment of renal anemia in rats with impaired kidney function and, unlike treatment with rhEPO, resulted in normalization of hypertensive blood pressure in a rat model of CKD. Notably, unlike treatment with the antihypertensive enalapril, the blood pressure normalization was achieved without a compensatory activation of the renin–angiotensin system. Thus, BAY 85-3934 may provide an approach to the treatment of anemia in patients with CKD, without the increased risk of adverse cardiovascular effects seen for patients treated with rhEPO. Clinical studies are ongoing to investigate the effects of BAY 85-3934 therapy in patients with renal anemia.

Longitudinal assessments of erythropoietin-stimulating agent responsiveness and the association with specific clinical outcomes in dialysis patients

BACKGROUND

Dose requirements of erythropoietin-stimulating agents (ESAs) can vary considerably over time and may be associated with cardiovascular outcomes. We aimed to longitudinally assess ESA responsiveness over time and to investigate its association with specific clinical end points in a time-dependent approach.

METHODS

The German Diabetes and Dialysis study (4D study) included 1,255 diabetic dialysis patients, of whom 1,161 were receiving ESA treatment. In those patients, the erythropoietin resistance index (ERI) was assessed every 6 months during a median follow-up of 4 years. The association between the ERI and cardiovascular end points was analyzed by time-dependent Cox regression analyses with repeated ERI measures.

RESULTS

Patients had a mean age of 66 ± 8.2 years; 53% were male. During follow-up, a total of 495 patients died, of whom 136 died of sudden death and 102 of infectious death. The adjusted and time-dependent risk for sudden death was increased by 19% per 5-unit increase in the ERI (hazard ratio, HR = 1.19, 95% confidence interval, CI = 1.07-1.33). Similarly, mortality increased by 25% (HR = 1.25, 95% CI = 1.18-1.32) and infectious death increased by 27% (HR = 1.27, 95% CI = 1.13-1.42). Further analysis revealed that lower 25-hydroxyvitamin D levels were associated with lower ESA responsiveness (p = 0.046).

CONCLUSIONS

In diabetic dialysis patients, we observed that time-varying erythropoietin resistance is associated with sudden death, infectious complications and all-cause mortality. Low 25-hydroxyvitamin D levels may contribute to a lower ESA responsiveness.

Association of higher erythropoiesis stimulating agent dose and mortality in children on dialysis

BACKGROUND

Higher doses of erythropoiesis-stimulating agents (ESA) have been associated with an increased risk of adverse outcomes in adults with chronic kidney disease (CKD) and end-stage kidney disease (ESRD), but to our knowledge no trials have been performed in children. We examined the association between ESA dose and all-cause mortality in a prevalent pediatric dialysis population.

METHODS

Retrospective cohort study utilizing national data on all prevalent dialysis patients aged <18 years from the Centers for Medicare and Medicaid Services' 2005 ESRD Clinical Performance Measures (CPM) project, linked to 18-month mortality records from the United States Renal Data System. Multivariate Cox proportional hazards regression was performed to determine the risk of mortality by mean weekly ESA dose.

RESULTS

Eight-hundred and twenty-nine children were included in the analysis; 7 % died during follow-up. A higher proportion of patients receiving ESA doses in the highest category (erythropoietin ≥350 units/kg/week or darbepoetin ≥1.5 units/kg/week) died (50 % vs 28 %, p = 0.002), and also demonstrated a trend toward lower hemoglobin (11.0 vs 11.4 g/dL, p = 0.05). In multivariate analysis, patients receiving the highest dose of ESA demonstrated an increased risk of mortality (hazard ratio 3.37; p value <0.01).

CONCLUSION

Higher ESA dose is independently associated with mortality in children on chronic dialysis.

Management of anemia with erythropoietic-stimulating agents in children with chronic kidney disease

Anemia management is an important component of the care provided to children with chronic kidney disease (CKD) and influences both morbidity and mortality risk. The introduction of recombinant human erythropoietin to the treatment regimen three decades ago revolutionized the therapy and significantly decreased the need for repeated blood transfusions and exposure to associated risks. Recent data on the efficacy and complications associated with erythropoietic-stimulating agent (ESA) usage has, however, prompted a reassessment of treatment-related recommendations. This review will address these recommendations, in addition to describing pediatric outcomes associated with current ESAs and presenting information on alternative ESAs, many of which will likely soon be incorporated into clinical practice.

Cost savings using a protocol approach to manage anemia in a hemodialysis unit

BACKGROUND

National guidelines recommend using anemia management protocols to guide treatment. The objective of this study was to determine if an anemia management protocol would improve hemoglobin (Hgb) indices in hemodialysis patients and to measure whether the protocol would reduce the use and cost of darbepoetin alfa (DBO) and intravenous (IV) iron in hemodialysis patients.

METHODS

An anemia management protocol was created and implemented for hemodialysis patients at our institution. A retrospective observational review of the use of DBO and IV iron as well as changes in Hgb, transferrin saturation and ferritin in 174 patients was conducted 6 months before and after implementation of the anemia protocol.

RESULTS

The number of Hgb measurements in the target range increased from 44.3 to 46.0% (p = 0.48) after protocol implementation. The mean weekly dose of DBO was reduced from 34.56 ± 31.12 to 31.11 ± 28.64 μg post-protocol implementation (p = 0.011), which translated to a cost savings of USD 41,649 over 6 months. The mean monthly IV iron dose also decreased from 139.56 ± 98.83 to 97.65 ± 79.05 mg (p < 0.005), a cost savings of USD 18,594 over the same time period.

CONCLUSION

The use of an anemia management protocol resulted in the deprescribing of DBO and iron agents while increasing the number of patients in the target Hgb range, which led to significant cost savings in the treatment of anemia.

Epidemiology, contributors to, and clinical trials of mortality risk in chronic kidney failure

Patients with chronic kidney failure--defined as a glomerular filtration rate persistently below 15 mL/min per 1·73 m(2)--have an unacceptably high mortality rate. In developing countries, mortality results primarily from an absence of access to renal replacement therapy. Additionally, cardiovascular and non-cardiovascular mortality are several times higher in patients on dialysis or post-renal transplantation than in the general population. Mortality of patients on renal replacement therapy is affected by a combination of socioeconomic factors, pre-existing medical disorders, renal replacement treatment modalities, and kidney failure itself. Characterisation of the key pathophysiological contributors to increased mortality and cardiorenal risk staging systems are needed for the rational design of clinical trials aimed at decreasing mortality. Policy changes to improve access to renal replacement therapy should be combined with research into low-cost renal replacement therapy and optimum clinical care, which should include multifaceted approaches simultaneously targeting several of the putative contributors to increased mortality.

Efficacy and safety of intravenous iron therapy for functional iron deficiency anemia in hemodialysis patients: a meta-analysis

BACKGROUND

Studies on benefits of intravenous iron therapy among hemodialysis patients with functional iron deficiency anemia have shown conflicting results. We conducted a meta-analysis to assess the efficacy and safety of intravenous iron in this subset of patients.

METHODS

We searched MEDLINE (through December 2012), the Cochrane Central Register of Controlled Trials and ClinicalTrials.gov for single-arm studies and randomized controlled trials (RCT) that examined the effect of intravenous iron for functional iron deficiency anemia in hemodialysis patients on anemia parameters and markers of oxidative stress and inflammation. Studies of absolute iron deficiency were excluded. Random-effect model meta-analyses were used to compute changes in outcomes of interest.

RESULTS

We identified 34 studies (2,658 patients), representing 24 single-arm studies, and 10 parallel-arm RCT. In the analyses of the study arms, intravenous iron therapy resulted in a significant increase in hemoglobin, serum ferritin, transferrin saturation rate, serum iron, reticulocyte hemoglobin content as well as a significant decrease in the percentage of hypochromic erythrocytes and erythropoietin dose. There were significant increases in plasma malonyldialdehyde level and thiobarbituric acid-reactive substances, and a decrease in neutrophil respiratory burst. The analyses of the RCT revealed less robust net changes in these parameters, and there was no increased risk of adverse events including infections, cardiac events and mortality.

CONCLUSIONS

Intravenous iron therapy for functional iron deficiency anemia in hemodialysis patients improves anemia parameters but exerts some effects on markers of oxidative stress that are of unclear clinical significance. The long-term safety and efficacy of this treatment strategy requires further study.

Blood disorders after kidney transplantation

Post transplant anemia (PTA) is a common issue in kidney transplant recipients. Most importantly it is associated with an impaired allograft function. Other important factors associated with PTA are immunosuppressive drugs (MPA, AZA and SRL), iron deficiency, infections (Parvo B19), older donor age, rejection episodes, an increased inflammatory state, and erythropoietin hyporesponsiveness. As there are no adequately powered RCTs in the kidney transplant population on anemia treatment with ESA, we have to rely on what we know from the large RCTs in the CKD population. The recently published KDIGO guidelines do not recommend treatment with ESA if Hb is >10 g/dl. Repletion of iron stores is emphasized. Post transplant leukopenia (PTL) and thrombocytopenia (PTT) are frequent complications especially in the first six months after kidney transplantation. Myelosuppression caused by immunosuppressive agents (MPA, AZA, SRL, rATG), antimicrobial drugs (VGCV), and CMV infection is the predominant cause. There are no widely accepted guidelines on treatment strategies, but most often dose reduction or discontinuation of causative medication is done. Most clinicians tend to decrease MPA dose, but this is eventually associated with an increase in acute rejection episodes. VGCV dose reduction (preemptive treatment instead of CMV prophylaxis) may be a successful strategy. In severe cases G-CSF treatment is an important management option and seems to be safe.

Anaemia management and mortality risk in chronic kidney disease

Renal anaemia is a frequent complication in patients with chronic kidney disease (CKD). Severe anaemia (haemoglobin <90 g/l) is associated with increased risks of mortality and cardiac complications, such as left ventricular hypertrophy and cardiovascular disease, and impaired quality of life. Randomized controlled trials have tested the hypothesis that increasing haemoglobin level using erythropoiesis-stimulating agents (ESAs) lowers these risks and improves quality of life. Use of ESAs to normalize haemoglobin levels (to ≥130 g/l) versus the partial correction of anaemia (to haemoglobin levels of 90-110 g/l) has repeatedly been shown to have no cardiac benefit and to be associated with no incremental improvement in outcomes and quality of life (except fatigue), but has been shown to be associated with an increased risk of cardiovascular events and death. Use of more-intense iron dosing has been proposed in order to reduce ESA dosing but liberal intravenous iron therapy is also associated with complications, and its long-term safety has not yet been adequately investigated. For patients with CKD on dialysis, US medication labels recommend administering ESAs at doses sufficient to avoid transfusions, whereas European and Canadian labels recommend targeting haemoglobin levels of 100-120 g/l and 110-120 g/l, respectively. Treatment of anaemia to haemoglobin levels of 90-110 g/l in patients with CKD accomplishes what we want--a reduced need for transfusions and possible reductions in fatigue, while avoiding high doses of ESA or iron in order to achieve a specific haemoglobin goal.