Hemoglobin variability in epoetin-treated hemodialysis patients

Maintaining over time clinical performance targets on anaemia correction in unselected population on chronic dialysis at 20 Italian centres. Data from a retrospective study for a clinical audit

BACKGROUND

The Italian and European Best Practice Guidelines (EBPG) recommend a target haemoglobin value greater than 11 g/dl in most patients with Chronic Kidney Diseases. However, it is still difficult to maintain these values at a steady rate. Thus, the main aim of the study was to evaluate, throughout 2005, how many patients steadily maintained the performance targets related to anaemia treatment.

METHODS

The survey was conducted on 3283 patients on haemodialysis (HD) and peritoneal dialysis (PD) at 20 Italian dialysis centres. 540 patients were randomly selected; each centre provided a statistically significant sample proportional to its total number of patients. Maintenance of the following target levels was assessed over time: Haemoglobin (HB) 11-12 gr/dl; Iron: 60-160 mcg/dl; Ferritin: 30-400 mcg/l; Transferrin: 200-360 mg/dl; Transferrin saturation percentage (TSAT %):> 25 <50; Dialysis doses (KT/V): >1.2 <2.0 for non-diabetic HD patients; >1.5 <2.2 for diabetic HD patients; DP: >1.8 <2.5.Outcome included:1- Percentage of target maintenance for each parameter.2- Erythropoietin dose in relation to dialysis techniques, presence of cancer or myeloma, diabetic status, Vitamin B therapy.3- Erythropoietin dose (International Units/kg/week) (IU/kg/wk) depending on: haemoglobin values, hospitalization of more than 3 days.

RESULTS

Mean age was 65.1; mean haemoglobin concentration over the whole population was 11.3 gr/dl (Standard Deviation (SD): 0.91). The clinical performance targets were maintained over time as follows: HB: 4.3% (Mean 11.43 gr/dl) (SD: 0.42); Ferritin: 71.1% (Mean: 250.23 mcg/L (SD:104.07); Iron: 95.0% (Mean 59.79 mcg/dl)(SD:16.76); Transferrin: 44.8% (Mean 216.83 mg/dl) (SD: 19,50); TSAT %: in 8.4% (Mean: 34.33% (SD: 6.56); HD KT/V: 61.0% (Mean:1.46) (SD: 0.7); PD KT/V:31.4% (Mean: 2.10) (SD: 0.02). The average weekly dose of Erythropoietin (IU/Kg/Wk) was significantly lower for the peritoneal dialysis technique; the higher haemoglobin values, the lower the Erythropoietin dose (IU/Kg/Wk).

CONCLUSION

A very low percentage of patients maintained haemoglobin target values over time. We need to identify precise criteria to evaluate the stability over time of clinical performance targets proposed by the guidelines.

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.

Generics: need for clinical concern?

The market of generic drugs is in continuous development in all countries, including Belgium. Their low cost explains their success in western and developed countries. However, clinical concerns have been raised when generics are used. Indeed, various studies suggest that generic substitution can be associated with reduced efficacy or (and) increased side-effects, particularly with drugs used in severe diseases or pathological states such as epilepsy, cardiac arrhythmia, prevention of graft-rejection, ... The generic drugs must have systemic bioavailability similar to that of the original drug. Thus, they have supposed similar therapeutic bioequivalence. However, similar pharmacokinetics does not imply identical therapeutic activity, particularly with drugs having narrow therapeutic indices such as anti-epileptics, anti-arrythmics ... In this case, switchability rather than prescribability may cause problems. Low pharmaceutical quality is more frequent when drugs are produced in certain countries, in some cases causing a real concern when activity and safety are considered.

Hemoglobin variability in chronic kidney disease: a cross-sectional study

BACKGROUND

The ability to maintain dialysis patients' hemoglobin (Hgb) within narrow targets remains a significant clinical problem. This study was designed to determine the variability in Hgb values for patients with chronic kidney disease (CKD) receiving or not receiving erythropoiesis-stimulating agents (ESAs) compared with patients on dialysis receiving ESAs.

METHODS

This cross-sectional review of anemia management in CKD and dialysis patients analyzed Hgb variability by patient-year, defined as the coefficient of variability calculated for individual patients. One hundred thirty-seven CKD patient-years and 350 dialysis patient-years were available for analysis. Hgb variability was defined as the coefficient of variability calculated as the individual patient's Hgb standard deviation divided by the patient's mean Hgb times 100.

RESULTS

The coefficient of variability in Hgb values were significantly less in patients with CKD not treated with ESAs than in patients with CKD treated with ESAs whether they were receiving dialysis (medians: 3.96 versus 8.53%, P < 0.05) or not receiving dialysis (medians: 3.96 versus 7.37%, P < 0.05).

CONCLUSION

CKD and hemodialysis patients receiving treatment with ESAs have significantly greater Hgb variability than patients with CKD not receiving ESAs. This finding suggests that the current practice pattern for the administration of exogenous ESAs is partly responsible for the observed Hgb variability.

Hemoglobin level variability in renal transplant patients treated with erythropoiesis stimulating agents

OBJECTIVE

Treatment with erythropoiesis stimulating agents (ESA) is associated with fluctuations in hemoglobin (Hb) levels. Recently, variability of Hb has been considered a factor that influences comorbidity and mortality among hemodialysis patients. The purpose of this analysis was to describe the phenomenon of Hb variability during ESA treatment, to study associated factors among kidney transplant patients, and to assess the impact on patient and graft survivals.

PATIENTS AND METHODS

Hb variability (defined as fluctuations of Hb +/- 1.5 g/dL) was assessed in 85 renal transplant patients treated with ESA for at least 3 months and with a minimum of 6 Hb measurements during 1 year.

RESULTS

Fifty-eight percent of the patients experienced Hb variability during follow-up. Only 3% of patients maintained stable Hb levels within the target range (11-13 g/dL), although 83% of patients maintained Hb levels >11 g/dL. Multivariate analysis showed that the clinical factors associated with variability were changes in ESA dose (relative risk [RR]: 2.92; 95% confidence interval [CI]: 1.0-8.5; P < .05), infectious events with hospitalization (RR: 1.95; 95% CI: 1.23-2.13; P < .05), and the use of sirolimus (RR: 1.1; 95% CI: 1.0-3.6; P < .05). When dose changes and hospitalization were excluded from the analysis, variability was an independent predictor of worsening graft function.

CONCLUSIONS

Hb variability is common in renal transplant patients treated with ESA. Only a few patients maintained Hb levels within the therapeutic range, although most had levels >11g/dL. Dose changes, inflammatory status, and worsening graft function are the determining factors of variability. Variability had no influence on patient survival, although it was a marker of worsening graft function.

Hemoglobin variability in nondialysis chronic kidney disease: examining the association with mortality

BACKGROUND AND OBJECTIVES

Anemia and hemoglobin (Hb) variability are associated with mortality in hemodialysis patients who are on erythropoiesis-stimulating agents (ESA). Our aim was to describe the degree of Hb variability present in nondialysis patients with chronic kidney disease (CKD), including those who were not receiving ESA, and to investigate the association between Hb variability and mortality.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Hb variability was determined using 6 mo of "baseline" data between January 1, 2003, and October 31, 2005. A variety of definitions for Hb variability were examined to ensure consistency and robustness.

RESULTS

A total of 6165 patients from 22 centers in seven countries were followed for a mean of 34.0 +/- 15.8 mo; 49% were prescribed an ESA. There was increased Hb variability with ESA use; the residual SD of Hb was 4.9 +/- 4.4 g/L in patients who were not receiving an ESA, compared with 6.8 +/- 4.8 g/L. Hb variability was associated with a small but significantly increased risk for death per g/L residual SD, irrespective of ESA use. Multivariate linear regression model explained only 11% of the total variance of Hb variability.

CONCLUSIONS

Hb variability is increased in patients who have CKD and are receiving ESA and is associated with an increased risk for death (even in those who are not receiving ESAs). This analysis cannot determine whether Hb variability causally affects mortality. Thus, the concept of targeting Hb variability with specific agents needs to be examined within the context of factors that affect both Hb variability and mortality.

Predictors of hyporesponsiveness to erythropoiesis-stimulating agents in hemodialysis patients

BACKGROUND

Identification of predictors of hyporesponsiveness to erythropoietin-stimulating agents (ESAs) in hemodialysis (HD) patients may help improve anemia management and reduce hemoglobin level variability.

STUDY DESIGN

We conducted repeated-measure and logistic regression analyses in a retrospective cohort of long-term HD patients to examine the association of iron markers and measures of renal osteodystrophy with ESA responsiveness. The ESA response coefficient at the individual level, ie, the least confounded dose-response association, was separated from the population level, assumed to represent confounding by medical indication.

SETTING/PARTICIPANTS

The national database of a large dialysis organization (DaVita Inc, El Segundo, CA) with 38,328 surviving prevalent HD patients during 12 months who received ESA for at least 3 consecutive calendar quarters was examined.

PREDICTORS

Serum levels of ferritin, iron saturation ratio, intact parathyroid hormone, and alkaline phosphatase. OUTCOMES/OTHER MEASUREMENTS: The main outcome was case-mix-adjusted hemoglobin response to quarterly averaged ESA dose at the individual level. The odds ratio (OR) of the greatest versus poorest ESA-response quartile at the patient level was calculated. OR less than 1.0 indicated ESA hyporesponsiveness, and OR greater than 1.0, enhanced responsiveness.

RESULTS

Mean ESA-response coefficients of the least to most responsive quartiles were 0.301 +/- 0.033 (SD), 0.344 +/- 0.004, 0.357 +/- 0.004, and 0.389 +/- 0.026 g/dL greater hemoglobin level per 1,000 U/wk greater ESA dose in each quarter, respectively. The ORs of greatest versus poorest ESA responsiveness at the patient level were serum ferritin level less than 200 ng/mL (0.77; 95% confidence interval [CI], 0.70 to 0.86; reference, 200 to 500 ng/mL), iron saturation ratio less than 20% (0.54; 95% CI, 0.49 to 0.59; reference, 20% to 30%), intact parathyroid hormone level of 600 pg/mL or greater (0.54; 95% CI, 0.49 to 0.60; reference, 150 to 300 pg/mL), and alkaline phosphatase level of 160 IU/L or greater (0.64; 95% CI, 0.58 to 0.70; reference, 80 to 120 IU/L). Lower estimated dietary protein intake and serum levels of nutritional markers were also associated with greater risk of ESA hyporesponsiveness.

LIMITATIONS

Our results may incorporate uncontrolled confounding. Achieved hemoglobin level may have different associations than targeted hemoglobin level.

CONCLUSIONS

In long-term HD patients, low iron stores, hyperparathyroidism, and high-turnover bone disease are associated with significant ESA hyporesponsiveness. Prospective studies are needed to verify these associations.

Maintenance of target hemoglobin level in stable hemodialysis patients constitutes a theoretical task: a historical prospective study

Maintenance of target hemoglobin (Hb) values in hemodialysis patients treated with erythropoiesis-stimulating agents (ESAs) remains difficult. We examined Hb variability in the clinical setting in hemodialysis patients. Hemodialysis patients treated with ESAs who maintained the recommended Hb range of 11-13 g per 100 ml over 3 months and were not admitted to hospital, did not require transfusion, and did not experience any major clinical event during this period were followed prospectively for 1 year. Anemia events, Hb variation events (any value out of +/-1.5 g per 100 ml of the median Hb level in the total follow-up period for the individual patient), risk factors for anemia, and Hb variation events were assessed. We studied 420 patients (63% males, mean age 61 years), 222 received short-acting erythropoietin (EPO) and 198 long-acting darbepoetin. A total of 4654 blood samples (mean 11.1 per patient-year) were analyzed. Only 3.8% of patients were maintained within the target Hb levels (11-13 g per 100 ml) during 1 year. Hb variation events occurred in 20.8% of laboratory values and anemia events in 14.7%, with a median time to the first event of 3 months. Treatment with short-acting EPO (vs long-acting darbepoetin), change of ESA dose in the previous visit, resistance index, and hospitalization were significant risk factors for both anemia events and Hb variation events. Our results show that Hb values are rarely maintained within the recommended guidelines even in more stable hemodialysis patients. Hb variability is frequently associated with clinical events or ESA dose changes. Long-acting darbepoetin achieved better Hb stability than short-acting EPO.

Hemoglobin variability and hyporesponsiveness: much ado about something or nothing?

Hemoglobin (Hb) variability is considered a discrete clinical entity that when present may presage poor clinical outcomes. However, Hb variability is an intrinsic property of biological systems and is present in all patients, those with and without the anemia of chronic kidney disease. Taken together, variability actually represents the integration of multiple influences at multiple levels in the life of a red cell, namely the summation of positive and negative influences on erythropoiesis. Thus, Hb variability may be interpreted as a mathematic function of time and is the result of a host of influences including definition of the normal Hb range, native erythron responsiveness/hyporesponsiveness, temporal changes in endogenous and exogenous erythropoiesis-stimulating agent (ESA) levels, the algorithms used to dose ESAs and their duration of action, the presence of biologically available iron, red cell turnover, and recyclable and non-recyclable blood loss and gain. When viewed within this construct of matrixed determinants, the source of hemoglobin variability is more readily identified. When variability is present but the etiology is not easily discerned, erythropoietic hyporesponsiveness must be considered and evaluated. Finally, integration of all of these concepts is possible within the context of an anemia management protocol.

Hemoglobin variability in anemia of chronic kidney disease

Hemoglobin levels in individuals with chronic kidney disease fluctuate frequently above or below the recommended target levels within short periods of time even though the calculated mean hemoglobin remains within the target range of 11 to 12 g/dl. Both pharmacologic features and dosing of erythropoiesis-stimulating agents may lead to cyclic pattern of hemoglobin levels within the recommended range. Several longitudinal studies highlight the complexity of maintaining stable hemoglobin levels over time. As a consequence, patients may risk increased hospitalization and mortality, because both low and high hemoglobin levels are associated with increased cardiovascular events and death. The duration of time that hemoglobin remains higher or lower than the target thresholds may be important to adverse outcomes. It is not clear whether adverse effects of hemoglobin variability are because of the therapy with erythropoiesis-stimulating agents and/or iron or despite such a therapy. Several factors affect hemoglobin variability, including those that are drug related, such as pharmacokinetic parameters, patient-related differences in demographic characteristics, and factors affecting clinical status, as well as clinical practice guidelines, treatment protocols, and reimbursement policies. Strategies that consider each of these factors and reduce hemoglobin variability may be associated with improved clinical outcomes.

Optimal and continuous anaemia control in a cohort of dialysis patients in Switzerland

BACKGROUND

Guidelines for the management of anaemia in patients with chronic kidney disease (CKD) recommend a minimal haemoglobin (Hb) target of 11 g/dL. Recent surveys indicate that this requirement is not met in many patients in Europe. In most studies, Hb is only assessed over a short-term period. The aim of this study was to examine the control of anaemia over a continuous long-term period in Switzerland.

METHODS

A prospective multi-centre observational study was conducted in dialysed patients treated with recombinant human epoetin (EPO) beta, over a one-year follow-up period, with monthly assessments of anaemia parameters.

RESULTS

Three hundred and fifty patients from 27 centres, representing 14% of the dialysis population in Switzerland, were included. Mean Hb was 11.9 +/- 1.0 g/dL, and remained stable over time. Eighty-five % of the patients achieved mean Hb >or= 11 g/dL. Mean EPO dose was 155 +/- 118 IU/kg/week, being delivered mostly by subcutaneous route (64-71%). Mean serum ferritin and transferrin saturation were 435 +/- 253 microg/L and 30 +/- 11%, respectively. At month 12, adequate iron stores were found in 72.5% of patients, whereas absolute and functional iron deficiencies were observed in only 5.1% and 17.8%, respectively. Multivariate analysis showed that diabetes unexpectedly influenced Hb towards higher levels (12.1 +/- 0.9 g/dL; p = 0.02). One year survival was significantly higher in patients with Hb >or= 11 g/dL than in those with Hb <11 g/dL (19.7% vs 7.3%, p = 0.006).

CONCLUSION

In comparison to European studies of reference, this survey shows a remarkable and continuous control of anaemia in Swiss dialysis centres. These results were reached through moderately high EPO doses, mostly given subcutaneously, and careful iron therapy management.

Long-term safety and tolerability of epoetin zeta, administered intravenously, for maintenance treatment of renal anemia

INTRODUCTION

The aim of this trial was to gather data on the long-term safety of a new erythropoietin preparation (epoetin zeta), focusing on the formation of anti-erythropoietin antibodies, when administered intravenously for maintenance of target hemoglobin concentration in anemic patients with end-stage renal failure receiving chronic hemodialysis. In addition, we aimed to provide information on the efficacy of epoetin zeta under open, noncontrolled conditions.

METHODS

Patients received epoetin zeta intravenously, 1-3 times/week for 56 weeks (overall patient group, n=745) or 108 weeks (Bulgarian subgroup, n=164). The aim of treatment was to maintain hemoglobin values between 10.5 and 12.5 g/dL with constant epoetin dosage. Primary (safety) endpoints were the occurrence of anti-erythropoietin antibodies and the evaluation of adverse events (AEs). Secondary (efficacy) endpoints included the mean weekly dose of epoetin per kg of body weight and mean hemoglobin concentrations.

RESULTS

No patients developed neutralizing anti-erythropoietin antibodies. The most commonly reported AEs were infections and infestations (34.1%); followed by injury, poisoning, and procedural complications (25.8%); and gastrointestinal disorders (21.9%); 37.3% of patients reported serious AEs. The hemoglobin values remained stable, with mean values after 56 weeks of 11.3-11.6 g/dL for the overall group and 11.1-11.6 g/dL for the Bulgarian subgroup. The dosage of epoetin zeta was stable throughout the course of the trial. No cases of lack of (or loss of ) efficacy were observed in the course of the trial.

CONCLUSIONS

The evaluation of the primary endpoints provided data supporting the intravenous administration of epoetin zeta in patients with chronic renal failure. Neutralizing antibodies against erythropoietin were not detected, and there were no reports of patients with increasing erythropoietin resistance. Our results suggest that intravenous administration of epoetin zeta is effective regarding its ability to maintain stabilized hemoglobin levels within the target range of 10.5-12.5 g/dL.

Association of hemoglobin variability and mortality among contemporary incident hemodialysis patients

BACKGROUND AND OBJECTIVES

Evidence exists that variability in hemoglobin may be an independent risk factor for mortality among hemodialysis patients. These observations were based on a 1996 cohort, a time when anemia management differed greatly from present. Design, settings, participants and measurements: A retrospective cohort study of patients incident to Fresenius Medical Care units between 2004 and 2005 (n = 6644). Hemoglobin variability (Hgb-Var) was defined for each subject as the residual SD of a linear regression model of time on hemoglobin.

RESULTS

The mean (SD) of Hgb-Var was 1.13 (0.55) g/dl. In the primary analysis, each g/dl increase of Hgb-Var was associated with an adjusted hazard ratio (95% confidence interval) for all-cause mortality of 1.11 (0.92 to 1.33). No significant interaction with Hgb-Var and mortality was found on the basis of age (P = 0.22), arterial disease (P = 0.45), Hgb slope (P = 0.68), or mean Hgb (P = 0.78). When Hgb-Var was defined by a regression model that included a quadratic term for time (enabling descriptions of curvilinear hemoglobin trajectories), model fit was greatly improved (P for difference <0.001). The corresponding adjusted hazard ratio (95% confidence interval) for all-cause mortality was 1.17 (0.93 to 1.49).

CONCLUSIONS

Hgb-Var was not found to be associated with all-cause mortality when examined in a contemporary incident hemodialysis population. More research is needed to determine whether differences in these findings compared with prior analyses relate to temporal trends in anemia management or from differences in the relationship between Hgb-Var and outcomes among incident versus prevalent hemodialysis patients.

[Hemoglobin variability in chronic renal failure patients]

In recent years, the question of hemoglobin (Hb) stability in patients with chronic renal failure has attracted the interest of medical experts. One of the most important reasons behind this interest is that maintaining the hemoglobin level within the new narrower target range is highly challenging in clinical practice. According to the results available from observational trials, instability of inter-patient hemoglobin levels may be associated with increased morbidity and mortality. To clarify the questions and answers related to this topic and to prepare an updated summary, we reviewed the scientific literature. With the help of the PubMed portal, the incidence, clinical importance, and reasons of Hb variability were summarized according to the available scientific literature. Hb variability is affected by multiple factors which are connected to the general condition of the patient as well as medical interventions and treatments. Also the fluctuation of serum Hb level is a physiological process and is a healthy sign of the capability of the normal human body to adapt. The characteristics and extent of Hb variability vary in patients with chronic renal failure and this topic requires further clinical research. More precise studies are needed in order to explore the differences in possible Hb variability as well as the change in variability caused by particular treatment methods. Finally, based on the available data, the results of future research, and on board scientific consensus, in a strategy for treatment of renal anemia, we should take into account the questions related to Hb stability and variability.

Methoxy polyethylene glycol-epoetin beta: a review of its use in the management of anaemia associated with chronic kidney disease

Methoxy polyethylene glycol-epoetin beta (Mircera) is a continuous erythropoietin receptor activator, with a long half-life (approximately 130 hours). In patients with anaemia associated with chronic kidney disease (CKD), both on and not on dialysis, who had not previously received an erythropoiesis-stimulating agent (ESA), methoxy polyethylene glycol-epoetin beta administered intravenously or subcutaneously once every 2 weeks resulted in a smooth and steady rise in haemoglobin levels. The response rates were high (up to 97.5%) in these patients at the end of the correction period; response rates with the comparator ESAs (epoetin alfa or beta, or darbepoetin alfa) were up to 96.3%. Moreover, patients with CKD on dialysis who had previously been treated with an ESA maintained stable haemoglobin levels (within +/-1 g/dL of baseline and within a range of 10-13.5 g/dL) when directly converted to methoxy polyethylene glycol-epoetin beta administered intravenously or subcutaneously once every 2 or 4 weeks. Methoxy polyethylene glycol-epoetin beta is generally well tolerated, with most adverse events being of mild to moderate severity, consistent with the co-morbidities known to occur in this patient group and those reported with other ESAs. In conclusion, in patients with anaemia associated with CKD, subcutaneous or intravenous methoxy polyethylene glycol-epoetin beta achieved a high haemoglobin response rate (ESA-naive patients) when administered once every 2 weeks and maintained stable haemoglobin levels (patients previously treated with ESAs) when administered once monthly.

History-adjusted marginal structural analysis of the association between hemoglobin variability and mortality among chronic hemodialysis patients

BACKGROUND AND OBJECTIVES

Hemoglobin variability is common among dialysis patients, and has been associated with increased mortality. The causal nature of this association has been difficult to ascertain because of potential time-dependent confounding, for which traditional statistical methods do not control.

DESIGN, SETTINGS, PARTICIPANTS, & MEASUREMENTS

A retrospective cohort of 34,963 Fresenius Medical care dialysis patients from 1996 was assembled. Hemoglobin variability, absolute hemoglobin level, and temporal hemoglobin trend were measured over rolling 6-mo exposure windows. Their association with mortality was estimated using history-adjusted marginal structural analysis that adjusts for time-dependent confounding by applying weights to observations inversely related to the predictability of observed levels of hemoglobin.

RESULTS

In the primary analysis, each g/dl increase in hemoglobin variability was associated with an adjusted hazard ratio (HR) [95% confidence interval (CI)] for all-cause mortality of 1.93 (1.20 to 3.10). Neither higher absolute hemoglobin level nor increasing hemoglobin trend were significantly associated with mortality; adjusted HR (95% CI) 0.85 (0.64 to 1.11) and 0.60 (0.25 to 1.45), respectively.

CONCLUSIONS

Marginal structural analysis demonstrates that hemoglobin variability is associated with increased mortality among chronic hemodialysis patients, and that this effect is more pronounced than appreciated using standard statistical techniques that do not take time-dependent confounding into account.

The effect of altitude on dosing and response to erythropoietin in ESRD

For poorly understood reasons, patients with end-stage renal disease (ESRD) differ substantially in their response to treatment with recombinant erythropoietin (EPO). Because hypoxia influences many of the biologic pathways involved in erythropoiesis, the altitude at which a patient lives may affect the dose-response relationship of EPO. In this retrospective cohort study, clinical data from 341,737 incident hemodialysis patients registered in the U.S. Renal Data System were combined with elevation data from the U.S. Geological Survey to address this question. Higher altitude was associated with smaller EPO doses and higher hematocrit levels. For example, compared with patients at sea level, patients living above 6000 ft received 19% less EPO (12.9 versus 15.9 thousand units/wk) but had hematocrit levels 1.1 points higher (35.7% versus 34.6%). These associations were found within subgroups defined by sex, race, age, calendar time, cause of ESRD, and dialysis center profit status, and persisted after adjustment for various potential confounding factors. Furthermore, resistance to EPO decreased with elevation. Our results suggest that ESRD patients living at high altitude either increase endogenous EPO production or respond better to endogenous and exogenous EPO.

The optimal hemoglobin in dialysis patients- a critical review

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

Serum albumin is strongly associated with erythropoietin sensitivity in hemodialysis patients

BACKGROUND AND OBJECTIVES

In hemodialysis patients, the hematological response to erythropoietin (epo) is variable and clinical factors that explain this variability are incompletely understood. We tested the hypothesis that the variability in hemoglobin (Hgb) response (epo sensitivity) is determined by key nutritional, inflammation, and oxidative stress markers.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Eighty-two consecutive patients on hemodialysis had 3 consecutive monthly predialysis evaluations of Hgb, total white blood cell (WBC) count, serum albumin, malondialdehyde (MDA), and monocyte chemoattractant protein-1 (MCP1). We analyzed the time course of Hgb in relationship to serum albumin, WBC, MDA, MCP1, epo and iron administration, and tests of iron sufficiency in a linear growth curve model.

RESULTS

Subjects with higher Hgb had a fall in Hgb and vice versa, regressing to a mean Hgb (SD) of 11.8 g/dl (1.8 g/dl). Whereas the average slope of Hgb was flat, the SD of slopes was 0.63 g/dl, which explained 39% of the variance in Hgb. Nonuse of epo was associated with a mean Hgb change of -0.18 g/dl (95% confidence interval [CI] -0.26 to -0.10) per 10,000 IU epo/mo (P < 0.05). Epo use was associated with steeper rate of change at 0.04 g/dl per mo per 10,000 IU (95% CI 0.01 to 0.07) (P < 0.01). Hgb at baseline was 0.73 g/dl higher for each 1-g/dl increase in albumin, and the rate of change increased by 0.49 g/dl per mo for each 1-g/dl increase in albumin concentration. WBC, MDA, or MCP1 had no role in predicting the baseline Hgb or its change over time.

CONCLUSIONS

Serum albumin concentration is an important predictor of both baseline Hgb and epo sensitivity in chronic hemodialysis patients. Factors that improve serum albumin may also improve Hgb in hemodialysis patients.

Hemoglobin variability and mortality in ESRD

Hemoglobin levels vary substantially over time in hemodialysis patients, and this variability may portend poor outcomes. For a given patient, hemoglobin concentration over time can be described by absolute levels, rate of change, or by the difference between observed level and expected level based on the preceding trend (i.e., seemingly random variability). We investigated the independent associations of these different methods of describing hemoglobin over time with mortality in a retrospective cohort of 34,963 hemodialysis patients. Hemoglobin concentration over time was modeled with linear regression for each subject, and the model was then used to define the subject's absolute level of hemoglobin (intercept), temporal trend in hemoglobin (slope), and hemoglobin variability (residual standard deviation). Survival analyses indicated that each 1g/dl increase in the residual standard deviation was associated with a 33% increase in rate of death, even after adjusting for multiple covariates. Patient characteristics accounted for very little of the variation in our hemoglobin variability metric (R2 = 0.019). We conclude that greater hemoglobin variability is independently associated with higher mortality.

Implications of Neocytolysis for Optimal Management of Anaemia in Chronic Kidney Disease

Erythropoietin is the major hormone regulator of erythrocyte production promoting the survival, as well as the differentiation and maturation, of erythroid progenitor cells. In addition to these well-characterized effects, it appears that an erythropoietin-responsive non-erythroid mechanism also mediates the selective destruction of young circulating erythrocytes (neocytes) when red cell mass becomes excessive - a process termed 'neocytolysis'. Endothelial cells appear to respond to a rapid decrease in circulating levels of erythropoietin by secreting cytokines (including TGF-alpha), which signal reticuloendothelial phagocytes to destroy neocytes. The result is a more rapid decrease in red cell mass than can be explained by natural erythrocyte senescence alone. The current pharmacologic approach to treatment of anaemia in chronic kidney disease may cause neocytolysis and could keep therapy from reaching its full potential. Understanding neocytolysis and its relationship to fluctuating serum erythropoietin levels might help to better understand optimal treatment with erythropoietic agents.

Renal anaemia: recent developments, innovative approaches and future directions for improved management

The morbidity, mortality and economic burden of chronic kidney disease (CKD) and associated anaemia are substantial. With the increasing numbers of patients who are likely to be affected in the future, approaches are required to improve anaemia management without increasing the burden on health-care professionals. A multidisciplinary approach to treatment, where early initiation of erythropoiesis-stimulating agents (ESA) is encouraged, may improve patient outcomes. Recent studies also suggest that the early use of iron therapy in patients with CKD not on dialysis may be associated with beneficial effects on haemoglobin levels. Another strategy to reduce the burden on health-care providers is to simplify anaemia management by extending the administration interval of ESA. Indeed, recent studies have explored the efficacy of extending the administration interval of ESA in clinical practice in CKD patients on dialysis and not on dialysis. The ability to maintain haemoglobin levels within guideline ranges at extended administration intervals may improve patient care and reduce the workload of health-care providers.

Anemia management in chronic kidney disease: what have we learned after 17 years?

Anemia management remains controversial in patients with chronic kidney disease (CKD). The overwhelming conclusion from retrospective data analyses show a strong correlation between higher hemoglobin values and improved outcomes, including mortality, hospitalization, left ventricular hypertrophy, and quality of life. However, the evidence available from two large prospective trials in CKD comparing hemoglobin values near the current target of 11-12 g/dl with normalization or near normalization were stopped, as there was a trend toward worsening outcomes in the higher hemoglobin groups. This disparity suggests that patients who have or achieve high hemoglobin values on low doses or no erythropoietin may be inherently different from the general CKD population. Therefore targeting to a hemoglobin value above the current recommendation with intermittent erythropoietin seems unwarranted until randomized prospective trials demonstrate both safety and efficacy.

What is needed to achieve a hemoglobin of 11.0-13.0 g/dl in end-stage renal disease

Effective treatment of anemia in end-stage renal disease (ESRD) results in reduced fatigue and improved quality of life. The National Kidney Foundation's 2006 anemia treatment guidelines recommend maintaining hemoglobin (Hb) at >11 g/dl, while noting that there is insufficient evidence to routinely maintain Hb levels > or =13.0 g/dl. Success in achieving Hb levels within these targets requires careful monitoring and adjustments to treatment. In addition, causes for diminished response and refractory anemia must be adequately evaluated. In this article, factors important for achieving Hb 11-13 g/dl in patients with ESRD are reviewed.

Hemoglobin cycling in hemodialysis patients treated with recombinant human erythropoietin

BACKGROUND

Treatment with recombinant human erythropoietin (rHuEPO) has been a major advance for the management of anemia in patients on hemodialysis. Therapy, however, is often observed to be associated with recurrent cyclic fluctuations in hemoglobin levels. The purpose of this analysis was to describe the phenomenology of hemoglobin cycling during rHuEPO treatment.

METHODS

Data were analyzed for 281 hemodialysis patients treated at Winthrop-University Hospital Dialysis Centers between 1998 and 2003. Eligible patients' first full 1-year period with less than 10 hospital days was studied. Hemoglobin cycling (cycles with amplitude >1.5 g/dL and duration >8 weeks) and excursions (half of one full cycle) were analyzed.

RESULTS

Greater than 90% of patients experienced hemoglobin cycling. The mean number of hemoglobin excursions was 3.1 +/- 1.1 per patient/year. The mean amplitude per hemoglobin excursion was 2.51 +/- 0.89 g/dL. The mean duration of hemoglobin excursions was 10.3 +/- 5.1 weeks. Factors associated with initiation of up excursions included increases in rHuEPO dose (84%), intravenous iron treatment initiation or increase in dose (27%), posthospital discharge (36%), factors associated with down excursions included rHuEPO dose hold (15%) or dose reduction (62%), infection (6%), discontinuation of intravenous iron therapy (5%), and hospitalization (14%). Patients with frequent hemoglobin cycling (>two full cycles per year) were characterized as being more responsive to rHuEPO [index of EPO responsiveness (ERI) 1036 +/- 659 compared to 1992 +/- 701 for other patients] (P = 0.02).

CONCLUSION

Hemoglobin cycling is a common occurrence in rHuEPO-treated hemodialysis patients. It is most closely associated with frequent rHuEPO dose changes, hospitalization, and iron treatment practices.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Epoetin alfa use in patients with ESRD: an analysis of recent US prescribing patterns and hemoglobin outcomes

BACKGROUND

It is unknown to what degree physicians adjust erythropoietin doses to achieve hemoglobin levels (11.0 to 12.0 g/dL [110 to 120 g/L]) recommended by the National Kidney Foundation-Kidney Disease Outcomes Quality Initiative (NKF-K/DOQI) for patients with end-stage renal disease receiving hemodialysis. Our objective is to examine epoetin alfa prescribing patterns for achieving the target hemoglobin level range in this population.

METHODS

Monthly hemoglobin levels and epoetin alfa doses from 2 large databases were retrospectively analyzed. One data set comprised 31,267 patients from the Fresenius Medical Care-North America (FMC-NA) database, and the other comprised 128,761 patients based on claims for Medicare services.

RESULTS

Longitudinal evaluation of the FMC-NA data set showed that hemoglobin levels in patients administered epoetin alfa cycled in and out of the NKF-K/DOQI hemoglobin target range, and doses were decreased in 98.8% of patients with persistent hemoglobin levels greater than 12.0 g/dL (> 120 g/L). Hemoglobin levels in patients from the Medicare data set that initially were outside the target range migrated into the range with epoetin alfa dose titration. FMC-NA patients with a 3-month average hemoglobin level less than 11.0 g/dL (< 110 g/L) were administered significantly greater epoetin alfa doses than those with average hemoglobin levels greater than 12.0 g/dL (> 120 g/L; 21,838 versus 13,503 U/wk; P < 0.0001). Less than 0.4% of patients administered epoetin alfa were persistently anemic (hemoglobin < 11.0 g/dL [< 110 g/L]) and were administered persistently high doses (> 30,000 U/wk), but failed to respond with a 0.5-g/dL or greater (> or = 5-g/L) increase in hemoglobin levels.

CONCLUSION

In these analyses, few hemodialysis patients experienced persistent anemia while being administered high epoetin alfa doses. Physicians appeared to appropriately adjust doses to achieve hemoglobin levels recommended by the NKF-K/DOQI guidelines.

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

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

The Impact of Guidelines for the Prevention of Anemia on Clinical Outcome

Guidelines for anemia management in renal disease are supported by substantial evidence demonstrating improvement in quality of life and objective markers of physical and cognitive performance. Randomized control studies demonstrating a survival benefit or improved cardiovascular outcomes are inconsistent. However, observational studies clearly demonstrate reduced mortality and hospitalization rate in patient cohorts on hemodialysis with hemoglobin measurements within the recommended target ranges. Data from patients in the predialysis phase of chronic kidney disease and those on peritoneal dialysis are limited and studies assessing the clinical impact of adherence to guidelines should be further explored in these populations. Available evidence suggests a proactive approach to anemia management should be practiced.

Reviews: Should the Target Hemoglobin for Patients with Chronic Kidney Disease Treated with Erythropoietic Replacement Therapy be Changed?

Recombinant human erythropoietin (rHuEPO, epoetin) revolutionized the treatment of anemia in patients with chronic kidney disease (CKD) when it was approved for use in the United States in 1989. Among dialysis patients, the mean hemoglobin (Hb) in patients undergoing dialysis rose from 7-8 g/dl prior to 1989 to 11-12 g/dl today. Among patients with CKD not on dialysis, epoetin use has not been as broadly applied as among dialysis patients, and although the mean Hb level in this patient population has increased, the impact has been less than in patients on dialysis. The optimal treatment target for epoetin remains controversial. Consistent with clinical practice guidelines, current practice in dialysis patients in the United States aims to maintain a target Hb of 11-12 g/dl, a level that is still well below the normal range. Debate centers on whether the current Hb target is too low and whether the target range is too narrow. Quality of life clearly improves in many individuals as Hb rises into the normal range from lower levels. In retrospective studies, higher Hb levels have been associated with lower risks of hospitalization and mortality. However, one large, prospective clinical trial has raised concern about normalizing Hb in hemodialysis patients with cardiac disease, and other prospective studies have not yet provided convincing evidence of significant benefits from normalizing Hb in dialysis-dependent and non-dialysis-dependent patients with CKD. A relative lack of information on non-dialysis-dependent patients with CKD and changes in fiscal policies regulating reimbursement for epoetin have contributed to uncertainty as to the best practices for anemia management in patients with CKD. There is increasing interest in the potential benefits of broadening the current target Hb range or eliminating an upper limit altogether and instead establishing a minimum Hb goal. While some extension of the upper limit of the currently recommended target Hb range might appear to be reasonable, the extent to which this should be extended, the benefits, risks, and costs of maintaining higher Hb levels in patients with CKD, and whether target Hb levels should be different in different CKD patient groups remains to be determined. Future efforts are likely to focus on selecting patient populations most likely to benefit from normalizing Hb, while adjusting the range of a subnormal Hb target for others.

The Dialysis Outcomes and Practice Patterns Study (DOPPS): design, data elements, and methodology

The Dialysis Outcomes and Practice Patterns Study (DOPPS) is a prospective, observational study designed to elucidate aspects of hemodialysis practice that are associated with the best outcomes for hemodialysis patients. In DOPPS I, 308 hemodialysis units from 7 countries participated, including 145 facilities from the United States (1996-2001), 62 facilities from Japan (1999-2001), and 101 facilities from France, Germany, Italy, Spain, and the United Kingdom (all 1998-2000). DOPPS II (2002-2004) has included 320 hemodialysis units and more than 12,400 hemodialysis patients from the 7 DOPPS I countries as well as Australia, Belgium, Canada, New Zealand, and Sweden. Dialysis units are chosen via a stratified random selection procedure to provide proportional sampling by region and type of facility within each country. In DOPPS I and II, longitudinal data have been collected from both a prevalent (cross-sectional) patient sample and an incident patient sample. Data have also been collected on numerous facility practice patterns. Most DOPPS analyses incorporate both facility- and patient-level data in regression-based analyses to investigate predictors of survival, hospitalization, quality of life, vascular access type, and other outcomes. DOPPS longitudinal data also help identify trends in subject characteristics, practice indicators, medication use, and outcomes. The DOPPS remains a unique source of data on hemodialysis patients and facilities. It continues to refine its methods of data collection and analysis with the goal of improving hemodialysis practice and end-stage renal disease patient lives worldwide.

Anemia management and outcomes from 12 countries in the dialysis outcomes and practice patterns study (DOPPS)

BACKGROUND

Anemia is common in hemodialysis (HD) patients.

METHODS

Data collected from nationally representative samples of HD patients (n = 11,041) in 2002 to 2003 were used to describe current anemia management for long-term HD patients at 309 dialysis units in 12 countries. Analyses of associations and outcomes were adjusted for demographics, 15 comorbid classes, laboratory values, country, and facility clustering.

RESULTS

For patients on dialysis therapy for longer than 180 days, 23% to 77% had a hemoglobin (Hgb) concentration less than 11 g/dL (<110 g/L), depending on country; 83% to 94% were administered erythropoietin (EPO). Mean Hgb levels were 12 g/dL (120 g/L) in Sweden; 11.6 to 11.7 g/dL (116 to 117 g/L) in the United States, Spain, Belgium, and Canada; 11.1 to 11.5 g/dL (111 to 115 g/L) in Australia/New Zealand, Germany, Italy, the United Kingdom, and France; and 10.1 g/dL (101 g/L) in Japan. Hgb levels were substantially lower for new patients with end-stage renal disease, and EPO use before ESRD ranged from 27% (United States) to 65% (Sweden). By patient, EPO use significantly declined with greater Hgb concentration (adjusted odds ratio, 0.61 per 1-g/dL [10-g/L] greater Hgb level; P < 0.0001), as did EPO dosage. Case-mix-adjusted mortality and hospitalization risk declined by 5% and 6% per 1-g/dL greater patient baseline Hgb level (P < or = 0.003 each), respectively. Furthermore, patient mortality and hospitalization risks were 10% to 12% lower for every 1-g/dL greater facility mean Hgb level. Patients were significantly more likely to have Hgb levels of 11 g/dL or greater (> or =110 g/L) if they were older; were men; had polycystic kidney disease; had greater albumin, transferrin saturation, or calcium levels; were not dialyzing with a catheter; or had lower ferritin levels. Facilities with greater intravenous iron use showed significantly greater facility mean Hgb concentrations. Mean EPO dose varied from 5,297 (Japan) to 17,360 U/wk (United States). Greater country mean EPO doses were significantly associated with greater country mean Hgb concentrations. Several patient characteristics were associated with greater EPO doses. Even in some countries with high intravenous iron use, 35% to 40% of patients had a transferrin saturation less than 20% (below guidelines).

CONCLUSION

These findings indicate large international variations in anemia management, with significant improvements during the last 5 years, although many patients remain below current anemia guidelines, suggesting large and specific opportunities for improvement.