Evidence-based recommendations for the clinical use of recombinant human erythropoietin

The erythropoietin receptor expressed in skeletal muscle is essential for mitochondrial biogenesis and physiological exercise

Erythropoietin (EPO) is a haematopoietic hormone that regulates erythropoiesis, but the EPO-receptor (EpoR) is also expressed in non-haematopoietic tissues. Stimulation of the EpoR in cardiac and skeletal muscle provides protection from various forms of pathological stress, but its relevance for normal muscle physiology remains unclear. We aimed to determine the contribution of the tissue-specific EpoR to exercise-induced remodelling of cardiac and skeletal muscle. Baseline phenotyping was performed on left ventricle and m. gastrocnemius of mice that only express the EpoR in haematopoietic tissues (EpoR-tKO). Subsequently, mice were caged in the presence or absence of a running wheel for 4 weeks and exercise performance, cardiac function and histological and molecular markers for physiological adaptation were assessed. While gross morphology of both muscles was normal in EpoR-tKO mice, mitochondrial content in skeletal muscle was decreased by 50%, associated with similar reductions in mitochondrial biogenesis, while mitophagy was unaltered. When subjected to exercise, EpoR-tKO mice ran slower and covered less distance than wild-type (WT) mice (5.5 ± 0.6 vs. 8.0 ± 0.4 km/day, p < 0.01). The impaired exercise performance was paralleled by reductions in myocyte growth and angiogenesis in both muscle types. Our findings indicate that the endogenous EPO-EpoR system controls mitochondrial biogenesis in skeletal muscle. The reductions in mitochondrial content were associated with reduced exercise capacity in response to voluntary exercise, supporting a critical role for the extra-haematopoietic EpoR in exercise performance.

Oral versus Intravenous Iron Supplementation in Peritoneal Dialysis Patients

The vast majority of erythropoietin (EPO)–treated peritoneal dialysis (PD) patients require iron supplementation. Most authors and clinical practice guidelines recommend primary oral iron supplementation in PD patients because it is more practical and less expensive. However, numerous studies have clearly demonstrated that oral iron therapy is unable to maintain EPO-treated PD patients in positive iron balance. Once patients become iron-deficient, intravenous iron administration has been found to more effectively augment iron stores and hematologic response than does oral therapy.

We recently performed a prospective, cross-over trial in 28 iron-replete PD patients and showed that twice-monthly outpatient iron polymaltose infusions (200 mg) were a practical and safe alternative to oral iron. That treatment produced significant increases in hemoglobin concentration and body iron stores. The additional expense of intravenous iron therapy was completely offset by reductions in EPO dosage.

Careful monitoring of iron stores is important in patients receiving intravenous iron supplementation in view of epidemiologic links with infection and cardiovascular disease. Nevertheless, a growing body of evidence suggests that, as has been found for hemodialysis patients, intravenous iron therapy is superior to oral iron supplementation in EPO-treated PD patients.

Experience with a Large Dose (500 MG) of Intravenous Iron Dextran and Iron Saccharate in Peritoneal Dialysis Patients

Objective

To compare efficacy in anemia correction and side effects of large doses of intravenous (IV) iron dextran and iron saccharate preparations in peritoneal dialysis (PD) patients.

Setting

Tertiary-care teaching hospital of University of Toronto.

Design

Retrospective analysis of 379 PD patients who attended PD clinics in past 5 years. Of these 379 patients, 62 were selected to receive IV iron based on ferrokinetic markers of iron deficiency, noncompliance to or ineffectiveness of oral iron, or increased erythropoietin (EPO) requirement.

Intervention

Sixty-one patients received two IV iron injections of 500 mg each, 1 week apart, 33 patients received iron dextran, 23 received iron saccharate, and 5 received both iron dextran and iron saccharate. One patient developed anaphylaxis to a test dose of iron dextran and was excluded from further therapy. Blood samples were collected before and 3 and 6 months after iron infusions.

Results

At 3 months, the group's average hemoglobin rose from 98.3 ± 18.3 g/L to 110.6 ± 16.4 g/L ( p < 0.0001). Ferritin rose from 104.9 ± 115.4 μg/L to 391.5 ± 294.1 μg / L ( p < 0.0001), and iron saturation from 0.17 ± 0.07 to 0.26 ± 0.19 ( p < 0.0001). Erythropoietin requirements fell from 7278.7 IU/week to 5900 IU/week ( p < 0.01). Five of the 34 patients who received iron dextran developed minor side effects and 1 patient had anaphylaxis to the test dose. Of the 23 patients who received iron saccharate, 1 had an anaphylactic reaction and 2 had transient chest pain, which subsided without therapy. Overall, there were more side effects with iron dextran (7.4% of injections) compared to the iron saccharate group (4.3% of injections), but this difference was statistically insignificant. Although statistically insignificant, there was an increase in the number of peritonitis episodes during the 6 months after IV iron infusion, especially with iron dextran, compared to the peritonitis episodes during the 6 months before iron infusions.

Conclusion

Our study indicates that IV iron in PD patients is effective in restoring iron stores and in decreasing EPO requirements. One anaphylactic reaction occurred in each group. Our data suggest that as much caution be exercised with iron saccharate as with iron dextran. The slight trend toward increased peritonitis rates after iron infusions needs to be investigated in a larger group of patients.

Erythropoietin use and abuse

Recombinant human erythropoietin (rhEPO) is arguably the most successful therapeutic application of recombinant DNA technology till date. It was isolated in 1977 and the gene decoded in 1985. Since then, it has found varied applications, especially in stimulating erythropoiesis in anemia due to chronic conditions like renal failure, myelodysplasia, infections like HIV, in prematurity, and in reducing peri-operative blood transfusions. The discovery of erythropoietin receptor (EPO-R) and its presence in non-erythroid cells has led to several areas of research. Various types of rhEPO are commercially available today with different dosage schedules and modes of delivery. Their efficacy in stimulating erythropoiesis is dose dependent and differs according to the patient's disease and nutritional status. EPO should be used carefully according to guidelines as unsolicited use can result in serious adverse effects. Because of its capacity to improve oxygenation, it has been abused by athletes participating in endurance sports and detecting this has proved to be a challenge.

Shared care: a study of patients' experiences with erythropoietin

A study was carried out to evaluate the impact of a shared care scheme on patients receiving erythropoietin treatment. A structured, self-administered questionnaire was given to adult patients receiving recombinant human erythropoietin. Completed questionnaires were received from 86 of 119 patients (72 per cent). Thirty respondents reported problems with administration. Reports of pain were significantly higher from those patients receiving Eprex than those using Recormon (P = 0.01, χ2 test). Doses were missed occasionally by 27 patients (31 per cent) and frequently by two patients. Supply problems had resulted in missed doses for 15 respondents (17 per cent). Eleven patients claimed that their general practitioner (GP) had not been aware of dosage adjustments initiated at the hospital. Thirty respondents (35 per cent) stated that they would like to speak to a pharmacist about their treatment.

In conclusion, the shared care scheme was effective and practical for most patients. However, some difficulties were identified. Problems involved administration, concordance, supply, and communication of dosage adjustments. Furthermore, there was a general lack of information about the treatment among many patients.

Landmark advances in the development of erythropoietin

This is a Minireview covering landmarks or milestones in the development of erythropoietin (EPO). Thirty-nine landmark advances have been identified, which cover the period 1863-2003. Several reports are included that directly support these original landmark advances. This Minireview also updates some of the advances in EPO research since my last Minireview update on EPO published in this journal in 2003. The areas of EPO research updated are: sites of production; purification, assay and standardization; regulation; action; use in anemias; extraerythropoietic actions; adverse effects; and blood doping. The new reports on the use of EPO in the therapy of myocardial infarction; stroke and other neurological diseases; diabetic retinopathy and other retinal diseases are also covered.

Use of agents stimulating erythropoiesis in digestive diseases

Anemia is the most common complication of inflammatory bowel disease (IBD). Control and inadequate treatment leads to a worse quality of life and increased morbidity and hospitalization. Blood loss, and to a lesser extent, malabsorption of iron are the main causes of iron deficiency in IBD. There is also a variable component of anemia related to chronic inflammation. The anemia of chronic renal failure has been treated for many years with recombinant human erythropoietin (rHuEPO), which significantly improves quality of life and survival. Subsequently, rHuEPO has been used progressively in other conditions that occur with anemia of chronic processes such as cancer, rheumatoid arthritis or IBD, and anemia associated with the treatment of hepatitis C virus. Erythropoietic agents complete the range of available therapeutic options for treatment of anemia associated with IBD, which begins by treating the basis of the inflammatory disease, along with intravenous iron therapy as first choice. In cases of resistance to treatment with iron, combined therapy with erythropoietic agents aims to achieve near-normal levels of hemoglobin/hematocrit (11-12 g/dL). New formulations of intravenous iron (iron carboxymaltose) and the new generation of erythropoietic agents (darbepoetin and continuous erythropoietin receptor activator) will allow better dosing with the same efficacy and safety.

Rationale and design of the oral HEMe iron polypeptide Against Treatment with Oral Controlled Release Iron Tablets trial for the correction of anaemia in peritoneal dialysis patients (HEMATOCRIT trial)

Background

The main hypothesis of this study is that oral heme iron polypeptide (HIP; Proferrin^® ES) administration will more effectively augment iron stores in erythropoietic stimulatory agent (ESA)-treated peritoneal dialysis (PD) patients than conventional oral iron supplementation (Ferrogradumet^®).

Methods

Inclusion criteria are peritoneal dialysis patients treated with darbepoietin alpha (DPO; Aranesp^®, Amgen) for ≥ 1 month. Patients will be randomized 1:1 to receive either slow-release ferrous sulphate (1 tablet twice daily; control) or HIP (1 tablet twice daily) for a period of 6 months. The study will follow an open-label design but outcome assessors will be blinded to study treatment. During the 6-month study period, haemoglobin levels will be measured monthly and iron studies (including transferring saturation [TSAT] measurements) will be performed bi-monthly. The primary outcome measure will be the difference in TSAT levels between the 2 groups at the end of the 6 month study period, adjusted for baseline values using analysis of covariance (ANCOVA). Secondary outcome measures will include serum ferritin concentration, haemoglobin level, DPO dosage, Key's index (DPO dosage divided by haemoglobin concentration), and occurrence of adverse events (especially gastrointestinal adverse events).

Discussion

This investigator-initiated multicentre study has been designed to provide evidence to help nephrologists and their peritoneal dialysis patients determine whether HIP administration more effectively augments iron stores in ESP-treated PD patients than conventional oral iron supplementation.

Trial Registration

Australia New Zealand Clinical Trials Registry number ACTRN12609000432213.

Association between erythropoietin requirements and antihypertensive agents

BACKGROUND

Angiotensin-converting enzyme inhibitors (ACI) and angiotensin II receptor blockers (ARB) have been reported to increase recombinant human erythropoietin (rHuEPO) requirements. We performed a cross-sectional study to investigate an association of antihypertensive agents including these two with the rHuEPO dose in chronic hemodialysis patients.

METHODS

We studied 625 patients undergoing hemodialysis therapy in 11 dialysis units. The association between the rHuEPO dose and antihypertensive agents was statistically analyzed.

RESULTS

The mean hemoglobin (Hb) level and rHuEPO dose corrected by body weight were 10.5 g/dl and 95.2 U/kg/week, respectively. When the patients were subdivided into four groups according to the number of prescribed antihypertensive agents (G-0, G-1, G-2, and G-3; patients prescribed with no medication, 1, 2, and >3 drugs, respectively), a significantly low dose of rHuEPO was observed in G-0 compared to the other groups. Unpaired t test showed a higher dose of rHuEPO in the presence of ARB, alpha-blockers, or calcium channel blockers (CCB). The rHuEPO dose was higher in the elderly, in females, and in patients with diabetes or hypertension. In multiple regression analysis, age, sex, rHuEPO dose, serum albumin level, and duration of dialysis therapy but not antihypertensive drugs were independent factors for the Hb level. In contrast, the rHuEPO dose was significantly associated with a low level of Hb, age, females, and CCB use. However, since CCB use was strongly associated not only with rHuEPO dose but also with systolic blood pressure and the use of alpha-blockers and ARB, these findings might be caused by erythropoietin (EPO)-induced hypertension.

CONCLUSION

There was an association between the number of antihypertensive agents and rHuEPO dose in chronic hemodialysis patients. However, no significant relation was indicated between ARB/ACI use and EPO requirements.

Blood management

CONTEXT

We provide an overview of the principles of blood management: the appropriate use of blood and blood components, with a goal of minimizing their use.

OBJECTIVE

To review the strategies that exploit combinations of surgical and medical techniques, technologic devices, and pharmaceuticals, along with an interdisciplinary team approach that combines specialists who are expert at minimizing allogeneic blood transfusion.

DATA SOURCES

A search on Medline and PubMed for the terms English and humans used in articles published within the last 20 years.

CONCLUSIONS

Blood management is most successful when multidisciplinary, proactive programs are in place so that these strategies can be individualized to specific patients.

Intravenous versus Oral Iron Supplementation in Peritoneal Dialysis Patients

Iron supplementation is required in a preponderance of peritoneal dialysis (PD) patients treated with erythropoietic stimulatory agents (ESAs). Although many authors and clinical practice guidelines recommend primary oral iron supplementation in ESA-treated PD patients, numerous studies have clearly demonstrated that, because of a combination of poor bioavailability of oral iron, gastrointestinal intolerance, and noncompliance, oral iron supplementation is insufficient for maintaining a positive iron balance in these patients over time. Controlled trials have demonstrated that, in iron-deficient and iron-replete PD patients alike, intravenous (IV) iron supplementation results in superior iron stores and hemoglobin levels with fewer side effects than oral iron produces. Careful monitoring of iron stores in patients receiving IV iron supplementation is important in view of conflicting epidemiologic links between IV iron loading and infection and cardiovascular disease. Emerging new iron therapies such as heme iron polypeptide and ferumoxytol may further enhance the tolerability, efficacy, and ease of administration of iron in PD patients.

Endogenous Erythropoietin Levels and Anemia in Long-Term Renal Transplant Recipients

BACKGROUND/AIM

Although anemia is a common complication after renal transplantation (RT), data concerning endogenous erythropoietin (EPO) levels in long-term RT recipients are rare. The goal of this study was to evaluate the prevalence of anemia within 6 months to 5 years after RT and to assess the relationship between the serum concentrations of endogenous EPO, graft function and grade of improvement of anemia.

METHODS

140 patients who had undergone RT were included in the group: 89 males (63.6%) and 51 females (36.4%), with an average age 46.8 +/- 12.8 years. The serum concentrations of EPO and creatinine (Cr) were tested in all the individuals and the values of the red blood component of blood count, serum ferritin (SF), plasma iron concentration, plasma total iron-binding capacity (TIBC), transferrin saturation (TS), folic acid and vitamin B(12) levels in the serum were determined. A statistical analysis of the results was performed using the correlation analysis, Mann-Whitney U test and Duncan's multiple range test.

RESULTS

Normal blood count values were found in 91 patients (65%), and a mild grade of anemia with a mean hemoglobin (Hb) 114.4 +/- 11.9 g/l was observed in 45 patients (32.1%), and 4 patients (2.9%) fulfilled the diagnostic criteria for post-transplantation erythrocytosis. Individuals with normal Hb values had a mean EPO serum concentration of 39.3 +/- 12.3 mU/ml (median 37.2) and the mean Cr was 133.8 +/- 36.9 micromol/l (median 122). Patients with anemia (Hb <120 g/l in females, Hb <130 g/l in males) had a mean EPO value of 47.0 +/- 26.6 mU/ml (median 36.0) and a mean Cr of 203.8 +/- 108.9 micromol/l (median 181). The difference in the Cr values was statistically significant (p < 0.0001), while the difference between the EPO concentrations was not significant. No relation of EPO serum concentration with regard to graft function was found in the analysis. A lack of storage iron (SF <10 microg/l in females, SF <22 microg/l in males) was found in 16 patients (11.4%), and a lack of functional iron (TS <20%) was found in 27 patients (19.3%).

CONCLUSIONS

Theprevalence of anemia in patients after transplantation was 32.1%. The most common cause of anemia is insufficient graft function development. The achieved values of the red component of blood count have no relation to the endogenous EPO serum concentrations.

Use of EPO in Critically Ill Patients With Acute Renal Failure Requiring Renal Replacement Therapy

BACKGROUND

Recombinant human erythropoietin (EPO) is used widely to treat anemia in patients with chronic kidney disease, but the benefits of EPO use in patients with acute renal failure (ARF) are unclear. In vitro and animal studies suggest that EPO may promote renal recovery and decrease mortality in ARF.

METHODS

We conducted a retrospective cohort study at a tertiary-care center to evaluate the use of EPO in 187 critically ill patients with ARF requiring renal replacement therapy.

RESULTS

Compared with patients not administered EPO (n = 116), patients administered EPO (n = 71) were significantly more likely to have baseline chronic kidney disease, have undergone vascular surgery, and have received intermittent hemodialysis, rather than continuous renal replacement therapy. In a propensity-adjusted analysis that controlled for differences between the 2 cohorts and baseline hemoglobin level, EPO use did not decrease the transfusion of packed red blood cells. Renal recovery was not more common in patients administered EPO: the odds ratio for renal recovery in the propensity-adjusted analysis was 0.63 (95% confidence interval, 0.30 to 1.3) with EPO use. In-hospital survival was more common in the EPO-treated group, but this potential benefit was not significant in propensity-adjusted analyses.

CONCLUSION

Although EPO use was not associated with a decrease in transfusion requirements or with renal recovery in our retrospective study, 37% of critically ill patients with ARF were treated with EPO at varying doses. A randomized controlled trial is needed to evaluate the potential benefits of EPO use in patients with ARF.

Rationale for blood conservation

BACKGROUND

Exposure of patients to allogeneic blood transfusion can be minimized or avoided by the systematic use of multiple blood conservation techniques. Current use of these technologies is variable.

METHODS

Review of pertinent English language literature.

RESULTS

Enthusiasm for preoperative autologous blood donation (PAD) has declined considerably, perhaps due to increased cost and inconvenience to patients. Acute normovolemic hemodilution (ANH) has several practical advantages over PAD, but has not become generally accepted as a blood conservation strategy. Erythropoietin, iron, and artificial oxygen carriers are pharmacologic alternatives.

CONCLUSIONS

Pharmacologic stimulation of erythropoiesis offers substantial potential to progress toward a goal of bloodless medicine. The potential of artificial blood substitutes is still being defined.

Traditional and nontraditional cardiovascular risk factors in chronic kidney disease

Chronic kidney disease (CKD) is public health problem, with as many as 20 million individuals affected in the United States. Patients with CKD should be considered in the highest-risk group for development of cardiovascular disease (CVD), and aggressive treatment of traditional and nontraditional risk factors should be instituted. Additional randomized controlled trials are urgently needed to evaluate potential treatments in this population. This article focuses attention on the major modifiable cardiovascular risk factors in CKD.

Improved survival with higher hematocrits: where is the evidence?

The Centers for Medicare and Medicaid Services (CMS) is reviewing Medicare coverage policy for recombinant human erythropoietin (epoetin) therapy. CMS officials are concerned that "Medicare spending on EPO may be higher than necessary without resulting in optimal patient benefit." Approximately 190 end-stage renal disease (ESRD) patients die each day-a mortality rate that has remained essentially unchanged since 1994-despite improvements in the "adequacy of dialysis, vascular access, and anemia management". To date, the evidence cited in support of a survival benefit of epoetin confuses the relationship between treatment response and outcomes with a causal effect of epoetin. A variety of mechanisms may account for a non-causal association between hematocrit and mortality can occur. We conclude that there is no basis for inferring the survival benefits (or detriments) of increasing a patient's hematocrit by adjusting the dosing of epoetin. Furthermore, we note that caution is required in administering large doses of epoetin to unresponsive patients in order to achieve the target hematocrit. A better understanding of the epoetin/survival relationship, well-grounded in science, is needed to provide a basis for CMS to improve its current epoetin policies, and may help to improve patient mortality.

Recombinant erythropoietin in clinical practice

The introduction of recombinant human erythropoietin (RHuEPO) has revolutionised the treatment of patients with anaemia of chronic renal disease. Clinical studies have demonstrated that RHuEPO is also useful in various non-uraemic conditions including haematological and oncological disorders, prematurity, HIV infection, and perioperative therapies. Besides highlighting both the historical and functional aspects of RHuEPO, this review discusses the applications of RHuEPO in clinical practice and the potential problems of RHuEPO treatment.

Clinical epidemiology of cardiac disease in dialysis patients: left ventricular hypertrophy, ischemic heart disease, and cardiac failure

Patients with end-stage renal disease (ESRD) are at extreme cardiovascular risk. At least half of all patients starting dialysis therapy have overt cardiovascular disease (CVD). In addition, recent studies suggest annual incidence rates for new-onset cardiac failure, peripheral vascular disease, ischemic heart disease (IHD), and stroke of approximately 7%, 7%, 5%, and 1%, respectively. High-level exposure to traditional risk factors, such as smoking and dyslipidemia, hemodynamic overload factors, such as anemia and hypertension, and a myriad of metabolic factors related to uremia are all likely to play a role. There has been explosive growth in observational studies and a heartening, if less dramatic, increase in risk factor intervention trials, suggesting that risk factor modification can lead to meaningful benefit.

Predialysis versus postdialysis hematocrit evaluation during erythropoietin therapy

American guidelines for the management of renal anemia by recombinant human erythropoietin (rHuEPO) recommend collecting a predialysis blood sample to evaluate hemoglobin (Hb) and hematocrit (Hct) levels in hemodialysis patients. Although a predialysis blood sample is appropriate for evaluating when to start rHuEPO treatment, the same sample would not be appropriate for evaluating the target Hb/Hct to be maintained, particularly when normal or near-normal values are pursued. We measured the degree of intradialytic and extradialytic variation of Hb, Hct, and body weight in 68 stable hemodialysis patients on maintenance subcutaneous rHuEPO treatment. Hb and Hct concentrations were determined before and after dialysis. In 16 patients, Hb and Hct concentrations also were assessed 24 hours after the end of dialysis. Predialysis versus postdialysis Hb and Hct concentrations for all patients were 10.5 +/- 1.3 g/dL versus 11.5 +/- 1.3 g/dL (P < 0.0001) and 32 +/- 4% versus 35 +/- 4% (P < 0.0001). The intradialytic percent variation (%Delta) of Hct and body weight were 10 +/- 6% and -6.3 +/- 3.5%. There was a close inverse correlation between %Delta of Hct and Hb and %Delta of body weight (P < 0.0001). In patients with body weight losses 2.5 kg or more per session, the mean %Delta of Hct was 12 +/- 7%. In the 16 patients studied 24 hours after the end of the dialysis session, Hct and Hb values remained significantly higher compared with the predialysis levels (P < 0.001), suggesting a slow reequilibration of the intravascular volume in the first 24 hours after hemodialysis. For these reasons, predialysis samples for monitoring the target Hb and Hct levels in patients treated by rHuEPO should be considered with caution.

A prospective crossover trial comparing intermittent intravenous and continuous oral iron supplements in peritoneal dialysis patients

BACKGROUND

Concomitant iron supplementation is required in the great majority of erythropoietin (Epo)-treated patients with end-stage renal failure. Intravenous (i.v.) iron supplementation has been demonstrated to be superior to oral iron therapy in Epo-treated haemodialysis patients, but comparative data in iron-replete peritoneal dialysis (PD) patients are lacking.

METHODS

A 12-month, prospective, crossover trial comparing oral and i.v. iron supplementation was conducted in all Princess Alexandra Hospital PD patients who were on a stable dose of Epo, had no identifiable cause of impaired haemopoiesis other than uraemia, and had normal iron stores (transferrin saturation >20% and serum ferritin 100-500 mg/l). Patients received daily oral iron supplements (210 mg elemental iron per day) for 4 months followed by intermittent, outpatient i.v. iron infusions (200 mg every 2 months) for 4 months, followed by a further 4 months of oral iron. Haemoglobin levels and body iron stores were measured monthly.

RESULTS

Twenty-eight individuals were entered into the study and 16 patients completed 12 months of follow-up. Using repeated-measures analysis of variance, haemoglobin concentrations increased significantly during the i.v. phase (108+/-3 to 114+/-3 g/l) compared with each of the oral phases (109+/-3 to 108+/-3 g/l and 114+/-3 to 107+/-4 g/l, P<0.05). Similar patterns were seen for both percentage transferrin saturation (23.8+/-2.3 to 30.8+/-3.0%, 24.8+/-2.1 to 23.8+/-2.3%, and 30.8+/-3.0 to 26.8+/-2.1%, respectively, P<0.05) and ferritin (385+/-47 to 544+/-103 mg/l, 317+/-46 to 385+/-47 mg/l, 544+/-103 to 463+/-50 mg/l, respectively, P=0.10). No significant changes in Epo dosages were observed throughout the study. I.v. iron supplementation was associated with a much lower incidence of gastrointestinal disturbances (11 vs 46%, P<0.05), but exceeded the cost of oral iron treatment by 6.5-fold.

CONCLUSIONS

Two-monthly i.v. iron infusions represent a practical alternative to oral iron and can be safely administered to PD patients in an outpatient setting. Compared with daily oral therapy, 2-monthly i.v. iron supplementation in PD patients was better tolerated and resulted in superior haemoglobin levels and body iron stores.

Once-Weekly Intravenous Administration of Recombinant Human Erythropoietin for Anemia following Hematopoietic Stem Cell Transplantation

Objective:

To determine the response to once-weekly intravenous administration of recombinant human erythropoietin (rHuEPO) in individuals who develop severe anemia following hematopoietic stem cell transplantation (HSCT).

Design:

A serum erythropoietin (EPO) concentration was obtained by chemiluminescence immunoassay in recipients of allogeneic or autologous stem cell transplantation who had developed severe anemia (hemoglobin <8.5 g/dL). If the erythropoietin concentration was not as high as predicted for the degree of anemia, rHuEPO was initiated at a dosage of 40,000 units intravenously once weekly. The medication was administered through a permanent indwelling central venous catheter on an outpatient basis. Hemoglobin concentration was measured at least weekly for up to 12 weeks prior to the administration of rHuEPO, and for an equivalent period following the initiation of therapy. Packed red blood cells were transfused for a hemoglobin concentration <8.5 g/dL. The mean weekly transfusion requirements prior to and following the initiation of rHuEPO were compared.

Results:

Ten consecutive patients who developed severe anemia after allogeneic (n = 8) or autologous (n = 2) HSCT for a variety of hematologic malignancies were eligible for the study. The median age was 43.5 years, and the male to female ratio was 3:7. There was no evidence of renal failure, iron or vitamin deficiency, hemoglobinopathy, or active blood loss. The median EPO concentration was 102 mU/mL. rHuEPO was begun at a median of 41 days following stem cell infusion. Patients received a median dose of 580 units/kg/wk. Two patients developed severe intestinal hemorrhage as a result of acute graft-versus-host disease. The remaining eight individuals received their last transfusion of packed red blood cells a median of 27 days after the initiation of rHuEPO therapy. The mean weekly transfusion requirement prior to and following the commencement of rHuEPO therapy was 0.93 and 0.40, respectively. This difference was statistically significant (p = 0.024).

Conclusions:

rHuEPO 40,000 units intravenously once weekly may reduce packed red blood cell transfusion requirements in some patients who develop severe anemia after HSCT. However, its use should be limited to individuals who are either intolerant of, or unwilling to use, the subcutaneous route of administration.

Adequacy of dialysis reduces the doses of recombinant erythropoietin independently from the use of biocompatible membranes in haemodialysis patients

BACKGROUND

The effect of the adequacy of dialysis on the response to recombinant human erythropoietin (rHuEpo) therapy is still incompletely understood because of many confounding factors such as iron deficiency, biocompatibility of dialysis membranes, and dialysis modality that can interfere.

METHODS

We investigated the relationship between Kt/V and the weekly dose of rHuEpo in 68 stable haemodialysis (HD) patients (age 65+/-15 years) treated with bicarbonate HD and unsubstituted cellulose membranes for 6-343 months (median 67 months). Inclusion criteria were HD for at least 6 months, subcutaneous rHuEpo for at least 4 months, transferrin saturation (TSAT) > or = 20%, serum ferritin > or = 100 ng/ml, and haematocrit (Hct) level targeted to 35% for at least 3 months. Exclusion criteria included HBsAg and HIV positivity, need for blood transfusions or evidence of blood loss in the 3 months before the study, and acute or chronic infections. Hct and haemoglobin (Hb) levels were evaluated weekly for 4 weeks; TSAT, serum ferritin, Kt/V, PCRn, serum albumin (sAlb), and weekly dose of rHuEpo were evaluated at the end of observation. No change in dialysis or therapy prescription was made during the study.

RESULTS

The results for the whole group of patients were: Hct 35 +/- 1.2%, Hb 12.1 +/- 0.6 g/dl, TSAT 29 +/- 10%, serum ferritin 204 +/- 98 ng/ml, sAlb 4.1 +/- 0.3 g/dl, Kt/V 1.33 +/-0.19, PCRn 1.11+/- 0.28 g/kg/day, weekly dose of rHuEpo 123 +/- 76 U/kg. Hct did not correlate with Kt/V, whereas rHuEpo dose and Kt/V were inversely correlated (r = -0.49; P < 0.0001). Multiple regression analysis with rHuEpo as dependent variable confirmed Kt/V as the only significant variable (P < 0.002). Division of the patients into two groups according to Kt/V (group A, Kt/V < or = 1.2; group B, Kt/V > or = 1.4), showed no differences in Hct levels between the two groups, while weekly rHuEpo dose was significantly lower in group B than in group A (group B, 86 +/- 33 U/kg; group A, 183 +/- 95 U/kg, P < 0.0001).

CONCLUSIONS

In iron-replete HD patients treated with rHuEpo in the maintenance phase, Kt/V exerts a significant sparing effect on rHuEpo requirement independent of the use of biocompatible synthetic membranes. By optimizing rHuEpo responsiveness, an adequate dialysis treatment can contribute to the reduction of the costs of rHuEpo therapy.

Erythropoietin, iron, and erythropoiesis

Recent knowledge gained regarding the relationship between erythropoietin, iron, and erythropoiesis in patients with blood loss anemia, with or without recombinant human erythropoietin therapy, has implications for patient management. Under conditions of significant blood loss, erythropoietin therapy, or both, iron-restricted erythropoiesis is evident, even in the presence of storage iron and iron oral supplementation. Intravenous iron therapy in renal dialysis patients undergoing erythropoietin therapy can produce hematologic responses with serum ferritin levels up to 400 μg/L, indicating that traditional biochemical markers of storage iron in patients with anemia caused by chronic disease are unhelpful in the assessment of iron status. Newer measurements of erythrocyte and reticulocyte indices using automated counters show promise in the evaluation of iron-restricted erythropoiesis. Assays for serum erythropoietin and the transferrin receptor are valuable tools for clinical research, but their roles in routine clinical practice remain undefined. The availability of safer intravenous iron preparations allows for carefully controlled studies of their value in patients undergoing erythropoietin therapy or experiencing blood loss, or both.

Erythropoietin, iron, and erythropoiesis

Recent knowledge gained regarding the relationship between erythropoietin, iron, and erythropoiesis in patients with blood loss anemia, with or without recombinant human erythropoietin therapy, has implications for patient management. Under conditions of significant blood loss, erythropoietin therapy, or both, iron-restricted erythropoiesis is evident, even in the presence of storage iron and iron oral supplementation. Intravenous iron therapy in renal dialysis patients undergoing erythropoietin therapy can produce hematologic responses with serum ferritin levels up to 400 μg/L, indicating that traditional biochemical markers of storage iron in patients with anemia caused by chronic disease are unhelpful in the assessment of iron status. Newer measurements of erythrocyte and reticulocyte indices using automated counters show promise in the evaluation of iron-restricted erythropoiesis. Assays for serum erythropoietin and the transferrin receptor are valuable tools for clinical research, but their roles in routine clinical practice remain undefined. The availability of safer intravenous iron preparations allows for carefully controlled studies of their value in patients undergoing erythropoietin therapy or experiencing blood loss, or both.

Intraperitoneal erythropoietin in children on peritoneal dialysis: A study of pharmacokinetics and efficacy

The pharmacokinetics and efficacy of intraperitoneal (IP) recombinant human erythropoietin (rHuEPO) were investigated in children undergoing chronic peritoneal dialysis. Eight children were administered a single dose of 100 U/kg of rHuEPO IP with 50 mL of dialysate into a dry peritoneal cavity after nighttime peritoneal dialysis. Serum erythropoietin (EPO) levels were measured at 0, 8, 12, and 24 hours. A mean peak EPO level of 187 mU/mL was obtained at 12 hours. The area under the curve was 5,818 mU/h/mL, and relative bioavailability was similar to that found using subcutaneous (SC) dosing. Nine children completed 11 to 12 weeks of IP rHuEPO therapy. The patients maintained a normal hematocrit (34% +/- 2.3%) with a mean final IP rHuEPO dosage that was not significantly greater than the mean previous SC dosage (IP, 290 +/- 194 U/kg/wk; SC, 279 +/- 126 U/kg/wk; P = not significant). There appeared to be a trend for a slightly increased risk for peritonitis compared with historical controls at our center (relative risk = 3.1; 95% confidence interval, 0.92 to 6.3). IP rHuEPO is effective in children undergoing continuous cycling peritoneal dialysis without requiring increased rHuEPO dosages, but the possibility of an increased risk for peritonitis will need to be further explored.

Iron status and iron supplementation in peritoneal dialysis patients

Iron deficiency represents an important problem in peritoneal dialysis patients, especially during erythropoietin therapy. A combination of serum ferritin, transferrin saturation, and/or the percentage of hypochromic red cells should be used to assess iron status in peritoneal dialysis patients. Primarily, oral iron supplementation should be the preferred therapy. However, most of the studies using oral substitution in erythropoietin-treated peritoneal dialysis patients show a progressive decline of serum ferritin. Therefore, parenteral iron supplementation is required in part of the patients, and the intravenous route should be preferred in these cases. Intravenous iron therapy is recommended if serum ferritin falls below 100 microg/liter and should be stopped if the serum ferritin level is more than 650 microg/liter. The optimal form of intravenous iron supplementation is still unclear. Injections once to three times per week restrict the patients' flexibility, but application of higher doses in longer intervals may lead to an impairment of neutrophil functions, probably connected to a higher risk of infection. We treated 17 stable peritoneal dialysis patients with 100 or 200 mg iron saccharate monthly over a period of six months and found an increase of transferrin saturation (from 12.1+/-1.6 to 20.9+/-2.4%, P = 0.026), serum ferritin (from 100.4+/-32.0 to 372.4+/-54.6 microg/liter, NS) and hematocrit (from 32.0+/-0.8% to 35.1+/-0.9%, P = 0.099). The required erythropoietin dosage could be reduced significantly (from 148.4+/-30.3 to 69.4+/-19.5 U/kg/week, P = 0.025). Side effects occurred in 0.9% after application of 100 mg and in 5.9% after injection of 200 mg iron saccharate. The incidence of catheter infections and peritonitis was the same in the period before and after the start of treatment. Further studies are needed to find the most suitable regime of iron supplementation for peritoneal dialysis patients.

Erythropoietin and renal transplantation

The advent of erythropoietin (rHuEPO) has revolutionized the treatment of anemia in end-stage renal disease. While many studies indicate beneficial effects of rHuEPO in hemodialysis, peritoneal dialysis and predialysis patients, the impact of the drug in renal transplantation is less clear. Treatment with rHuEPO may reduce the degree of allosensitization produced by random blood transfusion while still allowing the possibility of the transplant survival benefit derived from deliberate transfusion. Recovery from anemia post-transplantation is hastened by treatment with rHuEPO, while patients with failing allografts respond to rHuEPO in a fashion similar to dialysis patients, despite the concomitant use of immunosuppressives. The erythropoietic response to rHuEPO is abrogated during episodes of acute rejection, and restored when successful treatment of rejection has occurred. Iron therapy is a critical factor for support of erythropoiesis and prevention of absolute iron deficiency posttransplantation. In patients presenting for renal transplant, the balance of evidence suggests that there is no increase in the rate of delayed graft function, graft loss or vascular thrombosis for patients who had received prior rHuEPO therapy.

Acute-phase response predicts erythropoietin resistance in hemodialysis and peritoneal dialysis patients

We defined erythropoietin (EPO) resistance by the ratio of the weekly EPO dose to hematocrit (Hct), yielding a continuously distributed variable (EPO/Hct). EPO resistance is usually attributed to iron or vitamin deficiency, hyperparathyroidism, aluminum toxicity, or inflammation. Activation of the acute-phase response, assessed by the level of the acute-phase C-reactive protein (CRP), correlates strongly with hypoalbuminemia and mortality in both hemodialysis (HD) and peritoneal dialysis (PD) patients. In this cross-sectional study of 92 HD and 36 PD patients, we examined the contribution of parathyroid hormone (PTH) levels, iron indices, aluminum levels, nutritional parameters (normalized protein catabolic rate [PCRn]), dialysis adequacy (Kt/V), and CRP to EPO/Hct. Albumin level serves as a measure of both nutrition and inflammation and was used as another independent variable. Serum albumin level (deltaR2 = 0.129; P < 0.001) and age (deltaR2 = 0.040; P = 0.040) were the best predictors of EPO/Hct in HD patients, and serum albumin (deltaR2 = 0.205; P = 0.002) and ferritin levels (deltaR2 = 0.132; P = 0.015) in PD patients. When albumin was excluded from the analysis, the best predictors of EPO/Hct were CRP (deltaR2 = 0.105; P = 0.003) and ferritin levels (deltaR2 = 0.051; P = 0.023) in HD patients and CRP level (deltaR2 = 0.141; P = 0.024) in PD patients. When both albumin and CRP were excluded from analysis in HD patients, low transferrin levels predicted high EPO/Hct (deltaR2 = 0.070; P = 0.011). EPO/Hct was independent of PTH and aluminum levels, PCRn, and Kt/V. High EPO/Hct occurred in the context of high ferritin and low transferrin levels, the pattern expected in the acute-phase response, not in iron deficiency. In well-dialyzed patients who were iron replete, the acute-phase response was the most important predictor of EPO resistance.

Erythropoietin to minimize perioperative blood transfusion: a systematic review of randomized trials. The International Study of Peri-operative Transfusion (ISPOT) Investigators

Our aim was to perform a systematic review to determine the efficacy and side-effects of erythropoietin, given with or without autologous predonation, to patients undergoing orthopaedic or cardiac surgery. A number of studies have been done to determine whether erythropoietin minimizes exposure to perioperative allogeneic red cell transfusion. A systematic review of all randomized trials will provide the best estimate of the efficacy and side-effects of erythropoietin therapy. All randomized trials of erythropoietin in cardiac or orthopaedic surgery that reported the proportion of patients receiving perioperative allogeneic transfusion were included. The efficacy of erythropoietin was evaluated in subgroups of patients depending upon the route of administration, dose of erythropoietin, the type of control and the methodological quality of the study report. The odds ratio for the proportion of patients transfused with allogeneic blood in studies of erythropoietin to augment autologous donation was 0.42 (95% confidence limits 0.28-0.62; P < 0.0001) for orthopaedic surgery and 0.25 (95% CI 0.08-0.82; P = 0.02) for cardiac surgery. The odds ratio for erythropoietin alone was 0.36 (95% CI 0.24-0.56; P = 0.0001) in orthopaedic surgery and 0.25 (95% CI 0.06-1.04; P < 0.06) in cardiac surgery. The route of administration, dose of erythropoietin, type of control and methodological quality of the study report had no statistically significant effect upon the odds ratios. Although there was no convincing evidence that erythropoietin used alone increased the frequency of thrombotic complications, some studies found an excess of events in erythropoietin-treated patients, and the number of patients studied was relatively small. Erythropoietin, when given alone or to augment autologous donation, decreased exposure to perioperative allogeneic transfusion in orthopaedic and cardiac surgery. Further studies are required to definitively establish the safety of erythropoietin alone, to determine the optimal dose of perioperative erythropoietin, and to compare its efficacy and cost-effectiveness with other methods of minimizing perioperative transfusion.

C-reactive protein as an outcome predictor for maintenance hemodialysis patients

BACKGROUND

The possible association between inflammatory processes and other outcome measures in ESRD patients led us to measure the blood C-reactive protein (CRP) concentration in a large sample of hemodialysis patients, and to evaluate its statistical relationship with other common laboratory measures and patient survival. This was performed in a prospective, observational analysis with mortality as the principal outcome measure.

METHODS

One thousand fifty-four routine blood samples, collected from as many patients during June and July 1995 (one sample per patient), were randomly selected for measurement of CRP, prealbumin, and other routine laboratory measures. Six months after the initial blood tests, patient survival was determined: Logistic regression analysis was the primary statistical tool used to evaluate laboratory associations with odds of death. Bivariate regression and correlation analyses were performed using all available data.

RESULTS

The distribution of CRP values was skewed; approximately 35% of the values exceeded the upper limit of the laboratory's reference range. Serum albumin and prealbumin concentrations both correlated with the serum creatinine concentration (r = 0.378 and r = 0.347, respectively; P's < 0.001), and were inversely associated with the CRP (r = -0.254 and r = -0.354, respectively; P's < 0.001). CRP was also inversely associated with blood hemoglobin concentrations (r = -0.235; P < 0.001). Using multiple regression analysis to further explore these relationships, the serum creatinine concentration was inversely associated with CRP (r = -0.140; P < 0.001). However, after adjustment for the linkage of the serum creatinine with the serum albumin concentration (r = -0.378; P < 0.001), no relationship with creatinine was observed. Before and after adjustment for serum albumin and prealbumin concentration, the ferritin concentration correlated directly with CRP (r = 0.148; P < 0.001). Ferritin was inversely and highly correlated with total iron binding capacity (r = -0.516; P < 0.001). Independent associations of hemoglobin with albumin (t = 7.16; P < 0.001), prealbumin (t = 2.39; P = 0.017), and CRP (t = -4.27; P < 0.001) were observed. Also, the dose of erythropoietin was directly associated with the CRP concentration, before (r = 0.081, P = 0.009) and after (t = 2.03, P = 0.042) adjustment for the serum albumin and iron concentrations. CRP correlated directly with neutrophil (r = 0.318; P < 0.001) and platelet counts (r = 0.180; P < 0.001), but was weakly and inversely correlated with the lymphocyte count (r = -0.071; P = 0.04). A logistic regression analysis performed using the laboratory variables revealed a strong, independent, and inverse relationships between the serum albumin and creatinine concentrations, total lymphocyte count, and the odds risk of death. In this model, no significant relationship was observed between the odds risk of death and CRP.

CONCLUSIONS

The data presented herein suggest that: (1) strong predictable associations exist among laboratory proxies for malnutrition, anemia, and the acute phase reaction, and (2) the pathobiology implied by these laboratory abnormalities influence patients' mortal risk primarily through depletion of vital body proteins, not inflammation.

Hematopoietic growth factors and transfusion medicine

At least 20 different hematopoietic drugs (see Table 1) are currently under investigation. These most likely will impact on all aspects of transfusion therapy. Which agents to use and in what combinations will be the subject of scrutiny for many years to come as scientists try to recreate and enhance the process of hematopoiesis. Perhaps someday blood cells and hematopoietic progenitor cells can be manufactured for therapy with genetically selected phenotypes to avoid immune destruction and rejection. If this comes to pass, blood donations as we know them today, as a valuable adjunct to medical care, will fade into history, supplanted by the use of hematopoietic growth factors.

Impact of capitation on free-standing dialysis facilities: can you survive?

Proposed changes in the Medicare reimbursement method for end-stage renal disease (ESRD) patients prompted us to study the total cost of caring for the ESRD patients in northeast Indiana over a 1-year period. We hoped to ascertain the actual cost of caring for patients treated with different modalities, determine if we could compete in a capitated environment, and identify areas in which we might reduce these expenses. Six patients new to dialysis and 29 patients already receiving treatment underwent follow-up evaluation for 1 year. We tracked their cost of care for 1 year in the outpatient setting as well as in the hospital. We found the cost of caring for all patients was $43,044 per year. Patients new to dialysis cost $3,164 more to care for than patients already receiving dialysis treatment. Hospitalization expense was the primary component of that difference. Continuous ambulatory peritoneal dialysis (CAPD) patients were $14,570 less costly per year to care for than hemodialysis patients. This differential primarily related to decreased hospitalization. Vascular access expenses were a major component of both the outpatient and inpatient cost for hemodialysis patients. Our yearly expenditures for all patients compared with suggested capitated Medicare reimbursement rates suggested that our program could be successful in a new reimbursement model. Several areas of possible cost reduction were identified.

Cardiac disease in chronic uremia: management

Heart disease is a common cause of morbidity in end-stage renal disease (ESRD) patients. The management of heart disease in these patients requires a multidimensional approach to the management of heart failure, coronary disease, and arrhythmias, and to risk factors such as hypertension, anemia, secondary hyperparathyroidism, and electrolyte/acid-base disturbances. Coronary artery disease management includes use of antianginal drugs and revascularization of coronary arteries with angioplasty +/- stent placement or coronary artery bypass grafting. The long-term outcomes of these procedures need to be assessed and improved. Hypertension occupies a major role in the pathogenesis of heart disease in ESRD, and early and adequate control of hypertension is likely to have a major impact on the progression of cardiac disease. This entails the achievement of optimal volume status, combined with the appropriate use of antihypertensive agents such as calcium channel blockers, beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, vasodilators, alpha-blockers, and central sympatholytic drugs. In ESRD patients, specific dialysis-related complications such as intradialytic hypotension and pericardial effusion may have additional effects on cardiac function and require attention. The choice of dialysate composition and membrane may influence clinical outcomes with specific effects on cardiac performance.

Use of the medical differential diagnosis to achieve optimal end-stage renal disease outcomes

Compared with the general population, end-stage renal disease (ESRD) patients continue to have a higher than expected morbidity and mortality. Hypoalbuminemia, anemia, hypertension, and inadequate dialysis are all thought to contribute to the high morbidity and mortality among ESRD patients. Anemia algorithms should help to standardize the approach to anemia and the use of recombinant human erythropoietin (rHuEPO), but clinicians still must review each patient individually, searching for and treating the multitude of interrelated factors that affect rHuEPO responsiveness. Hypoalbuminemia is a very strong predictor of increased morbidity and mortality in dialysis and nondialysis patients. The causes of hypoalbuminemia are multifactorial, and diagnosis of the cause of hypoalbuminemia is usually elusive. The basis of the poorer survival in US dialysis patients remains controversial, but inadequate dialysis has been implicated. To assure adequate dialysis, the dialysis prescription must be individualized for each patient, and delivered dialysis must be routinely monitored. Hypertension is associated with left ventricular hypertrophy, which is also an important determinant of survival in ESRD patients. Hypertension should be treated in ESRD patients in conjunction with other interventions that are known to reverse left ventricular hypertrophy. Special efforts must be made in the medical management of hypoalbuminemia, anemia, hypertension, and dialysis treatment adequacy to improve survival in patients with ESRD.

Iron management in end-stage renal disease

One of the important components of successful anemia therapy in patients with end-stage renal disease (ESRD) treated with recombinant human erythropoietin is the maintenance of adequate available iron. To accomplish this task, iron status must be serially monitored and supplemental iron administered as required. Among nonuremic subjects, the body's iron supply is tightly conserved, and iron deficiency usually develops only when chronic blood loss occurs. In patients with ESRD, iron deficiency occurs more frequently, because of increased external losses of iron, decreased availability of the body's storage of iron, and perhaps a deficit in intestinal iron absorption. Detecting iron deficiency in these patients can be difficult because of the inaccuracy of available diagnostic tests. The goals of iron therapy in ESRD include the prevention of iron deficiency by chronically supplementing iron, and the prompt treatment of overt iron deficiency. Oral iron supplements are inexpensive and safe, but poor patient compliance and reduced intestinal absorption may limit their effectiveness. Intravenous iron supplements have a greater efficacy then oral iron, which must be weighed against the small risk of allergic reactions. We present strategies for using the various diagnostic tests and treatment modalities to effectively manage iron supply for predialysis, hemodialysis, and peritoneal dialysis patients.