Achieving target hematocrit in dialysis patients: new concepts in iron management

Chronic Kidney Disease Induced by Cisplatin, Folic Acid and Renal Ischemia Reperfusion Induces Anemia and Promotes GATA-2 Activation in Mice

Anemia is a common feature of chronic kidney disease (CKD). It is a process related to erythropoietin deficiency, shortened erythrocyte survival, uremic erythropoiesis inhibitors, and disordered iron homeostasis. Animal models of CKD-induced anemia are missing and would be desirable in order to study anemia mechanisms and facilitate the development of novel therapeutic tools. We induced three different models of CKD in mice and evaluated the development of anemia characteristics. Mice were subjected to unilateral ischemia-reperfusion or received repeated low doses of cisplatin or folic acid to induce nephropathy. Renal function, kidney injury and fibrotic markers were measured to confirm CKD. Moreover, serum hemoglobin, ferritin and erythropoietin were analyzed. Renal mRNA levels of HIF-2α, erythropoietin, hepcidin, GATA-2, and GATA-2 target genes were also determined. All three CKD models presented increased levels of creatinine, urea, and proteinuria. Renal up-regulation of NGAL, KIM-1, and TNF-α mRNA levels was observed. Moreover, the three CKD models developed fibrosis and presented increased fibrotic markers and α-SMA protein levels. CKD induced decreased hemoglobin and ferritin levels and increased erythropoietin levels in the serum. Renal tissue showed decreased erythropoietin and HIF-2α mRNA levels, while an increase in the iron metabolism regulator hepcidin was observed. GATA-2 transcription factor (erythropoietin repressor) mRNA levels were increased in all CKD models, as well as its target genes. We established three models of CKD-induced anemia, regardless of the mechanism and severity of kidney injury.

Association between platelet-related hemostasis impairment and functional iron deficiency in hemodialysis patients

Hemostasis impairment and iron deficiency are relatively frequent in hemodialysis patients. Both conditions may contribute to anemia. The aim of our study was to explore possible associations between hemostasis impairment and iron deficiency by employing recently introduced methods for measurement of both conditions. Sixty-three hemodialysis patients were studied, with 30 age-matched, healthy controls. Hemostasis impairment was detected by in vitro closure time tests (collagen/epinephrine cartridge: CEPI; collagen/adenosine diphosphate (ADP) cartridge: CADP), whereas (functional) iron deficiency was measured by reticulocyte hemoglobin content (CHr) and the percentage of hypochromic red cells (HRC). We found that the patient group (N=14) with functional iron deficiency (CHr<29) had significantly delayed in vitro closure times in comparison to the patients (N=49) without functional iron deficiency. Furthermore, both types of closure time (CEPI and CADP) correlate highly significantly with CHr (P=0.002, and P=0.001). Such an association was not observed between in vitro closure time and HRC. We found a significant correlation between hemostasis impairment (measured by in vitro closure time) and iron deficiency (measured by CHr) in hemodialysis patients. This correlation has not previously been reported. It seems that in hemodialysis patients the hemostasis impairment affects (functional) iron deficiency, most likely by facilitating excessive blood loss and consequent iron deficiency. Thus, it appears that a delayed in vitro closure time along with decreased CHr may identify hemodialysis patients who suffer (occult) blood loss and/or excessive blood loss during hemodialysis procedure. The clinical value of this finding should be tested in larger studies.

Hepcidin in Anemia and Inflammation in Chronic Kidney Disease

Maintaining the correct iron balance is crucial for health. Our understanding of the molecular control of iron metabolism has increased dramatically over the past 5 years due to the discovery of hepcidin. This is a circulating antimicrobial peptide mainly synthesized in the liver, which has been recently proposed as a factor regulating the uptake of dietary iron and its mobilization from macrophages and hepatic stores. Inflammation causes an increase of production of hepcidin, which is a potent mediator of anemia of chronic diseases. Anemia in chronic kidney disease is mainly due to erythropoietin deficiency but these patients often have a chronic inflammatory state. The aim of this review is to summarize the current knowledge dealing with a possible role of hepcidin in iron metabolism and its regulation, particularly in kidney disease. In addition, current methods of determination of hepcidin are reviewed.

Influence of inflammation on the relation between markers of iron deficiency in renal replacement therapy

Iron deficiency is an important factor in the management of anemia in both dialysis and transplant patients. Serum ferritin and transferrin saturation (TS) may be influenced by the presence of inflammation. Recently, the soluble transferrin receptor (s-TfR) has been considered to be a marker of functional iron stores. In this study, parameters of the iron state were investigated in terms of agreement (assessed by kappa) with the diagnosis of iron deficiency and with inflammation. The study was performed in 38 hemodialysis, 31 continuous ambulatory peritoneal dialysis, and 21 anemic renal transplant patients. CRP and amyloid A protein (AAP) were studied as markers of inflammation. Iron deficiency was defined as ferritin <100 mg/L, TS <20%, or s-TfR >1.76 mg/mL. We observed that s-TfR levels were significantly related to both dialysis duration (r = 0.28 in dialysis and r = 0.60 in transplant patients, both P <.05) and PTH levels (r = 0.23 in dialysis and r = 0.55 in transplant patients, both P <.05). Among the transplant group, ferritin and TS, as well as TS and s-TfR were significantly related (r = 0.84 and r = -0.64, respectively), but not s-TfR and ferritin. Among the dialysis group, ferritin and TS, and also TS and s-TfR, were significantly related (r = 0.35 and r = -0.30, respectively), whereas s-TfR and ferritin were not. In the transplant group, the kappa value for agreement between ferritin and TS in the diagnosis of iron deficiency was 0.76 (P =.006), and 0.33 (P =.04), respectively. Among patients with CRP levels <0.3 mg/L or AAP levels <6.4 mg/L, the relation between parameters of iron state was more robust. The kappa value for agreement between ferritin and s-TfR was 0.49 (P =.006) in the dialysis group and 1 (P =.002) for that between ferritin and TS in the transplant group. Our results suggest that PTH levels may influence s-TfR levels. Discordance between ferritin, TS, and s-TfR as markers of iron deficiency might be explained by the effects of inflammation.

Impact of a Pharmacist-Implemented Anemia Management in Outpatients with End-Stage Renal Disease in Japan

Given the absence of standard guidelines for use of recombinant human erythropoietin in patients with end-stage renal disease in Japan, in the present study, pharmacists actively managed the erythropoietin therapy, and the therapeutic and pharmacoeconomic outcome was evaluated. We compiled in-hospital guidelines for proper use of erythropoietin for outpatients with renal anemia under hemodialysis, and made recommendations, particularly about changes in the doses of erythropoietin and administration of iron preparations, to physicians. The clinical test values and the dosages of erythropoietin were monitored for 9 months and analyzed. As results of our participation, the number of renal anemia patients with over 30% of the hematocrit value as a therapeutic target increased from 7 to 32 among 41 patients. Twenty three of the 41 patients could decrease the dose of erythropoietin, and 5 patients could cease receiving the drug. Monthly total units of erythropoietin used for the 41 patients could also be decreased from 915000 units to 642000 units, resulting in considerable improvement of cost performance. Thus, active participation of pharmacists in management of renal anemia had great therapeutic and pharmacoecomic impact in Japan, as in North America.

Sodium ferric gluconate complex in the treatment of iron deficiency for patients on dialysis

Intravenous iron has been found to be an important adjunctive therapy in the treatment of anemia for patients on dialysis. In the United States, iron dextran had been the only form available for parenteral use until 1999. This agent has been associated with a concerning number of severe adverse reactions, in some cases resulting in patients' deaths. Recently, a form of iron used for many years in Europe, sodium ferric gluconate complex in sucrose, was approved for intravenous use in the United STATES: Because this agent does not contain the immunogenic dextran component of iron dextran, it is expected that the safety profile of this drug should be superior to that of iron dextran. The purpose of this review is to critically appraise the relevant literature and to synthesize the information into a strategy for clinical use of this drug.

Iron Sucrose Injection

Each month, subscribers to The Formulary® Monograph Service receive five to six researched monographs on drugs that are newly released or are in late Phase III trials. The monographs are targeted to your Pharmacy and Therapeutics Committee. Subscribers also receive monthly one-page summary monographs on the agents that are useful for agendas and pharmacy/nursing in-services. A comprehensive target drug utilization evaluation (DUE) is also provided each month. The monographs are published in printed form and on diskettes that allow customization. Subscribers to the The Formulary Monograph Service also receive access to a pharmacy bulletin board called The Formulary Information Exchange (The F.I.X). All topics pertinent to clinical pharmacy are discussed on The F.I.X.

Through the cooperation of The Formulary, Hospital Pharmacy publishes selected reviews in this column. If you would like information about The Formulary Monograph Service or The F.I.X., call The Formulary at 800-322-4349. The April 2001 Formulary monographsare on caspofungin, peginterferon alfa-2b, ziprasidone, 90Y ibritumomab tiuxe-tan, and Abarelix depot. The DUE is on caspofungin.

Anemia management of adult hemodialysis patients in the US results: from the 1997 ESRD Core Indicators Project

BACKGROUND

The Health Care Financing Administration's End-Stage Renal Disease (ESRD) Core Indicators Project collects clinical information on prevalent adult patients receiving in-center hemodialysis (HD) care in the United States to assess the quality of care delivered. Although hematocrit values, transferrin saturations, and iron prescription practices have improved over the last five years, we sought to determine whether continued opportunities for improvement of this domain of care exist.

METHODS

A random sample of 7292 adult in-center HD patients was selected. Dialysis facility staff provided clinical information for the period of October through December 1996 for 6858 (94%) patients; complete laboratory information was available from 4991 (73%) returned forms. Hematocrit values, transferrin saturations, serum ferritin concentrations, epoetin alfa dosing, and iron prescriptions were abstracted from patient medical records to assess anemia management practices.

RESULTS

The mean hematocrit for this cohort was 32.6 +/- 3.5%. Seventy-two percent of patients had hematocrit values> 30%. Forty-two percent had hematocrit values of 33 to 36%, and 10% were severely anemic (hematocrit <28%). Ninety-four percent of the patients received epoetin alfa intravenously (i.v.) and 6% subcutaneously. The mean weekly dose was 202.4 +/- 137.2 units/kg. The mean transferrin saturation was 27.4 +/- 12.6%; 73% of patients had a mean transferrin saturation > or = 20%. The mean serum ferritin concentration was 386 +/- 422 ng/mL; 79 and 12% of patients had a serum ferritin concentration of> 100 and> 800 ng/mL, respectively. Nine percent of the sample (N = 434) had a transferrin saturation <20% and serum ferritin concentration <100 ng/mL. Regardless of the patient's transferrin saturation, approximately three fourths of the patients received either oral or i.v. iron, and only approximately one half of the patients received i.v. iron. Of the subset of patients with transferrin saturation <20% and serum ferritin concentration <800 ng/mL, only 53% were prescribed intravenous iron. Multivariate linear regression analysis revealed that serum albumin, urea reduction ratio, age, and transferrin saturation were significantly positively associated with hematocrit. Epoetin alfa dose and serum ferritin concentration were significantly and negatively associated with the hematocrit (P < 0.001).

CONCLUSION

Although substantial improvements have been made in anemia management for adult in-center HD patients over the past five years, significant opportunities persist to improve iron prescription practices.

Sodium Ferric Gluconate Complex in Sucrose Injection

Each month, subscribers to The Formulary® Monograph Service receive five to six researched monographs on drugs that are newly released or are in late Phase III trials. The monographs are targeted to your Pharmacy and Therapeutics Committee. Subscribers also receive monthly one-page summary monographs on the agents that are useful for agendas and pharmacy/nursing in-services. A comprehensive target drug utilization evaluation (DUE) is also provided each month. The monographs are published in printed form and on diskettes that allow customization. Subscribers to the The Formulary Monograph Service also receive access to a pharmacy bulletin board called The Formulary Information Exchange (The F.I.X). All topics pertinent to clinical pharmacy are discussed on The F.I.X.

Through the cooperation of The Formulary, Hospital Pharmacy publishes selected reviews in this column. If you would like information about The Formulary Monograph Service or The F.I.X., call The Formulary at 800-322-4349. The August 1999 Formulary monographs are on rofecoxib/celecoxib, rosiglitazone, rivastigmine, doxercalciferol, oseltamivir. The DUE is on rosiglitazone.

Indices of iron status in continuous ambulatory peritoneal dialysis patients

Data for iron-status indices in continuous ambulatory peritoneal dialysis patients are limited. The reliability of commonly used indices for the diagnosis of iron-deficiency anemia in peritoneal dialysis patients is still unknown. To study diagnostic values of iron-status indices, including serum ferritin, transferrin saturation, reticulocyte hemoglobin content, and bone marrow-stainable iron, 21 stable anemic peritoneal dialysis patients who have been treated with erythropoietin and oral iron supplementation for more than 3 months were enrolled in this study. The mean age was 51.4 +/- 2.9 years; dialysis duration, 28.7 +/- 5.1 months; initial hemoglobin, 8.4 +/- 0.2 g/dL; erythropoietin dosage, 71 +/- 2 micro/kg/wk; serum albumin, 3.5 +/- 0.1 g/dL; intact parathyroid hormone (PTH), 233 +/- 44 ng/mL; serum ferritin, 643 +/- 135 ng/mL; transferrin saturation, 33.93% +/- 3.9%; and reticulocyte hemoglobin content, 31.6 +/- 4 pg. Bone marrow aspiration was performed in all patients to determine marrow iron content and exclude hematological disorders. All patients were treated with 1, 000 mg of intravenous ferric saccharate infusion in two divided doses more than 1 week apart. Patients who responded to the iron infusion within 3 months by increasing serum hemoglobin of greater than 1 gm/dL more than baseline were defined as being functional iron deficient before the intravenous iron infusion. Serum ferritin, transferrin saturation, and reticulocyte hemoglobin content were followed serially after iron infusion. Fifteen patients (71.4%) responded to the iron administration, indicating iron deficiency. Nine of 13 (69%) patients with the presence of bone marrow-stainable iron still responded to intravenous iron supplementation, suggesting functional iron deficiency. Absence of bone marrow-stainable iron was not a sensitive marker for the diagnosis of iron deficiency, 25% sensitivity. No single value of iron-status indices that can definitely exclude iron-deficiency anemia in peritoneal dialysis patients was found. Therefore, failure to increase hemoglobin concentration after intravenous iron administration should be shown before excluding iron-deficiency anemia as a cause of poor erythropoietic response to erythropoietin therapy.

Optimal care of the pediatric end-stage renal disease patient on dialysis

This manuscript is an effort on behalf of the American Society of Pediatric Nephrology to provide recommendations designed to optimize the clinical care of pediatric patients with end-stage renal disease (ESRD). Although many of the recommendations are evidenced-based with the supporting data being derived from a variety of sources, including patient registries, others are opinion-based and derived from the combined clinical experience of the authors. In all cases, it is recommended that the decision to initiate dialysis should be made only after an assessment of a combination of biochemical and clinical characteristics. Irrespective of the choice of dialysis modality (hemodialysis v peritoneal dialysis), dialysis efficacy should be measured regularly, and the dialysis prescription should be designed to achieve target clearances. Attention to dialysis adequacy, control of osteodystrophy, nutrition, and correction of anemia is mandatory, because all may influence patient outcome in terms of growth, cognitive development, and school performance. Finally, the availability of a multidisciplinary team of pediatric specialists is desirable to provide all facets of pediatric ESRD care, including renal transplantation, in an optimal manner. Future clinical research efforts intended to address topics such as dialysis adequacy, anemia management, and growth should be encouraged.