The intensity of hemodialysis and the response to erythropoietin in patients with end-stage renal disease

Short-term effect of low-dose roxadustat combined with erythropoiesis-stimulating agent treatment for erythropoietin-resistant anemia in patients undergoing maintenance hemodialysis

Background

Erythropoietin resistance is present in some patients with chronic kidney disease, especially in those undergoing hemodialysis, and is often treated using roxadustat rather than iron supplements and erythropoiesis-stimulating agents (ESAs). However, some patients cannot afford full doses of roxadustat. This retrospective study investigated the efficacy of low-dose roxadustat combined with recombinant human erythropoietin (rhuEPO) therapy in 39 patients with erythropoietin-resistant renal anemia undergoing maintenance hemodialysis (3-4 sessions/week).

Methods

The ability of the combination of low-dose roxadustat and rhuEPO to increase the hemoglobin concentration over 12 weeks was assessed. Markers of iron metabolism were evaluated. Eligible adults received 50-60% of the recommended dose of roxadustat and higher doses of rhuEPO.

Results

The mean hemoglobin level increased from 77.67 ± 11.18 g/dL to 92.0 ± 8.35 g/dL after treatment, and the hemoglobin response rate increased to 72%. The mean hematocrit level significantly increased from 24.26 ± 3.99% to 30.04 ± 3.69%. The soluble transferrin receptor level increased (27.29 ± 13.60 mg/L to 38.09 ± 12.78 mg/L), while the total iron binding capacity (49.22 ± 11.29 mg/L to 43.91 ± 12.88 mg/L) and ferritin level (171.05 ± 54.75 ng/mL to 140.83 ± 42.03 ng/mL) decreased.

Conclusion

Therefore, in patients with ESA-resistant anemia who are undergoing hemodialysis, the combination of low-dose roxadustat and rhuEPO effectively improves renal anemia and iron metabolism.

Investigation of the Relationship between Lean Muscle Mass and Erythropoietin Resistance in Maintenance Haemodialysis Patients: A Cross-Sectional Study

Each patient undergoing maintenance haemodialysis (MHD) has a different response to erythropoiesis-stimulating agents (ESAs). Haemodilution due to fluid overload has been shown to contribute to anaemia. Body mass index (BMI) has been shown to influence ESA response in dialysis patients; however, BMI calculation does not distinguish between fat and lean tissue. The association between lean muscle mass and erythropoietin hyporesponsiveness is still not well-known among MHD patients. We designed a cross-sectional study and used bioimpedance spectroscopy (BIS) to analyse the relationship between body composition, haemoglobin level, and erythropoietin resistance index (ERI) in MHD patients. Seventy-seven patients were enrolled in the study group. Compared with patients with haemoglobin ≥ 10 g/dL, those with haemoglobin < 10 g/dL had higher serum ferritin levels, malnutrition−inflammation scores (MIS), relative overhydration, ESA doses, and ERIs. In multivariate logistic regression, higher ferritin levels and MIS were the only predictors of lower haemoglobin levels. The ERI was significantly positively correlated with age, Kt/V, ferritin levels, and MIS and negatively correlated with albumin levels, BMI, and lean tissue index (LTI). Multivariate linear regression analysis revealed that ferritin levels, BMI, and LTI were the most important predictors of ERI. In MHD patients, using BIS to measure body composition can facilitate the development of early interventions that aim to prevent sarcopenia, support ESA responsiveness, and, consequently, improve anaemia management.

Clinical significance of a novel reticulocyte-based erythropoietin resistance index in HD patients: A retrospective study

INTRODUCTION

The erythropoietin resistance index (ERI) is an indicator of erythropoiesis-stimulating agent (ESA) responsiveness and is typically calculated using Hb. However, Hb does not directly reflect ESA-induced erythropoiesis because of its long-term nature. We thus designed a novel ERI calculated with reticulocyte Hb (RetHb), a real-time index, and investigated its association with mortality in HD patients.

METHODS

We calculated the ERI using the change in RetHb before and after ESA administration (ERI_ΔRetHb ) and retrospectively analyzed its association with 3-year all-cause mortality using Kaplan-Meier survival curves and Cox regression analyses.

RESULTS

A total of 102 patients were included. Patients with the highest ERI_ΔRetHb had the worst prognosis according to the Kaplan-Meier survival curves (Log-rank p = 0.02). Multivariate Cox regression analysis showed that the ERI_ΔRetHb was significantly and independently associated with all-cause mortality (hazard ratio: 9.82, 95% CI [1.50, 64.41], p = 0.02).

CONCLUSION

The ERI_ΔRetHb was significantly and independently associated with all-cause mortality in HD patients.

Effects of blood urea nitrogen independent of the estimated glomerular filtration rate on the development of anemia in non-dialysis chronic kidney disease: The results of the KNOW-CKD study

BACKGROUND

Anemia is a common complication of chronic kidney disease (CKD). Blood urea nitrogen (BUN) in CKD represents nitrogenous uremic toxin accumulation which could be involved in anemia of CKD. We investigated the effects of BUN independent of estimated glomerular filtration rate (eGFR) on anemia in non-dialysis CKD (NDCKD).

METHODS

This prospective study included 2,196 subjects enrolled in the KoreaN Cohort Study for Outcome in Patients With Chronic Kidney Disease (KNOW-CKD) cohort with BUN and hemoglobin level data. Initially, we investigated the association between BUN and hemoglobin level. To examine the impact of baseline BUN on the incident anemia, a longitudinal study was performed on 1,169 patients without anemia at study enrollment. BUN residuals were obtained from the fitted curve between BUN and eGFR. Anemia was defined as a hemoglobin level of <13.0 g/dL for men and <12.0 g/dL for women.

RESULTS

BUN residuals were not related to eGFR but to daily protein intake (DPI), while BUN was related to both eGFR and DPI. BUN was inversely associated with hemoglobin level (β -0.03; 95% confidence interval [CI] -0.04, -0.03; P <0.001) in the multivariable linear regression analysis adjusted for multiple confounders including eGFR, and BUN residual used instead of BUN was also inversely associated with hemoglobin level (β -0.03; 95% CI -0.04, -0.02; P <0.001). Among the 1,169 subjects without anemia at baseline, 414 (35.4%) subjects newly developed anemia during the follow-up period of 37.5 ± 22.1 months. In the multivariable Cox regression analysis with adjustment, both high BUN level (Hazard ratio [HR] 1.02; 95% CI 1.01, 1.04; P = 0.002) and BUN residual used instead of BUN (HR 1.02; 95% CI 1.00, 1.04; P = 0.031) increased the risk of anemia development. Moreover, BUN, rather than eGFR, increased the risk of anemia development in patients with CKD stage 3 in the multivariable Cox regression.

CONCLUSION

Higher BUN levels derived from inappropriately high protein intake relative to renal function were associated with low hemoglobin levels and the increased risk of anemia independent of eGFR in NDCKD patients.

Anemia: A Connection Between Heart Failure and Kidney Failure

Erythropoiesis-stimulating agents (ESAs) have improved the quality of life and reduced the need for transfusions in patients with chronic kidney disease. However, randomized trials showed no benefit but possible safety issues following high doses of ESAs given to reach normal hemoglobin levels. Iron therapy is used together with ESA; when given proactively, it may reduce the risk of mortality and cardiovascular events in hemodialysis patients. Recent trials also showed benefits of intravenous iron therapy in patients with heart failure. New drugs for correcting anemia may retain the present efficacy of ESAs as antianemic drugs and reduce cardiovascular risks.

Managing Anemia across the Stages of Kidney Disease in Those Hyporesponsive to Erythropoiesis-Stimulating Agents

BACKGROUND

Patients with CKD frequently have anemia that results from iron-restricted erythropoiesis and inflammation. Anemia of CKD is currently managed with iron supplements and erythropoiesis-stimulating agents (ESAs) to promote erythropoiesis and with RBC transfusion in severe cases. Hyporesponse to ESAs, or the need for larger than usual doses to attain a given hemoglobin (Hb) level, is associated with increased morbidity and mortality and presents a pressing clinical challenge, particularly for patients on dialysis. This paper reviews ESA hyporesponse and potential new therapeutic options in the management of anemia of CKD.

SUMMARY

The most common causes of ESA hyporesponse include iron deficiency and inflammation, and to a lesser degree, secondary hyperparathyroidism, inadequate dialysis, malnutrition, and concomitant medications. Management of ESA hyporesponse is multipronged and involves treating low level infections, ensuring adequate nutrition, and optimizing iron status and dialysis modality, although some patients can remain refractory. Inflammation directly increases production and secretion of hepcidin, contributes to an impaired response to hypoxia, and suppresses proliferation of erythroid progenitors. Coordination of renal and hepatic erythropoietin (EPO) production and iron metabolism is under the control of hypoxia-inducible factors (HIF), which are in turn regulated by HIF-prolyl hydroxylases (HIF-PHs). HIF-PHs and hepcidin are therefore attractive potential drug targets particularly in patients with ESA hyporesponse. Several oral HIF-PH inhibitors have been evaluated in patients with anemia of CKD and have been shown to increase Hb and reduce hepcidin regardless of inflammation, iron status, or dialysis modality. These sustained effects are achieved through more modest increases in endogenous EPO compared with ESAs. Key Messages: Treatments that address ESA hyporesponse remain a significant unmet clinical need in patients with anemia of CKD. New therapies such as HIF-PH inhibitors have the potential to address fundamental aspects of ESA hyporesponse and provide a new therapeutic option in these patients.

Effect of increased blood flow rate on renal anemia and hepcidin concentration in hemodialysis patients

Background

Increasing the blood flow rate (BFR) is a useful method for increasing Kt/V and the clearance for low molecular solutes. Hemodialysis patients are often anemic due to hypoerythropoiesis and their chronic inflammatory state. Hepcidin, a hormone that regulates iron homeostasis, is considered as an indicator of iron deficiency in patients with end-stage renal disease. This study aimed to investigate the effects of an increased BFR during hemodialysis on serum hepcidin levels and anemia.

Methods

Between April 2014 and March 2016, 22 chronic dialysis patients (11 men [50.0 %]; mean [± standard deviation] age, 72 ± 12 years) undergoing maintenance hemodialysis treatment, thrice weekly, were enrolled and followed prospectively for 24 months. In April 2014, the BFR was 200 mL/min; in April 2015 this was increased to 400 mL/min, which was within acceptable limits. The dialysate flow rate remained stable at; 500mlL/min. Blood samples were collected in March 2015 and 2016. The primary endpoint was the comparison of the amounts of erythropoiesis-stimulating agent (ESA) required.

Results

The increased BFR increased the Kt/V and contributed to significantly decreased urea nitrogen (UN) (p = 0.015) and creatinine (Cr) (p = 0.005) levels. The dialysis efficiency was improved by increasing the BFR. Ferritin (p = 0.038), hepcidin (p = 0.041) and high-sensitivity interleukin-6 (p = 0.038) levels were also significantly reduced. The ESA administered was significantly reduced (p = 0.004) and the Erythropoietin Resistant Index (ERI) significantly improved (p = 0.031). The reduction rates in UN (p < 0.001), Cr (p < 0.001), and beta-2 microglobulin (p = 0.017) levels were significantly greater post the BFR increase compared to those prior to the BFR increase. However, hepcidin was not affected by the BFR change.

Conclusions

Increasing BFR was associated with hemodialysis efficiency, and led to reduce inflammatory cytokine interleukin-6, but did not contribute to reduce C-reactive protein. This reduced hepcidin levels, ESA dosage and ERI. Hepcidin levels were significantly correlated with ferritin levels, and it remains to be seen whether reducing hepcidin leads to improve ESA and iron availability during anemia management.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02426-7.

The association of standard Kt/V and surface area-normalized standard Kt/V with clinical outcomes in hemodialysis patients

INTRODUCTION

A previous study demonstrated that the surface area-normalized standard Kt/V (SAstdKt/V) was better associated with mortality than standard Kt/V (stdKt/V). This study investigates the association of SAstdKt/V and stdKt/V with mortality, anemia, and hypoalbuminemia in a larger patient cohort with a longer follow-up period.

METHODS

We included adult patients on thrice-weekly hemodialysis in the USRDS database and excluded amputated patients. StdKt/V and SAstdKt/V were calculated from the available single-pool Kt/V. Patients were categorized into five groups according to their stdKt/V and SAstdKt/V: <2.00, 2.00-2.19, 2.20-2.39, 2.40-2.59, and ≥2.60. Hazard ratios (HR) and odds ratios (OR) were calculated using Cox and logistic regression analysis respectively.

FINDINGS

There were 507,656 patients included in the analysis. The patients had a median age of 65.5 years with a median follow-up period of 2 years. Thirty-four percent died during follow-up. HRs for mortality progressively decreased as SAstdKt/V increased in both unadjusted and adjusted models. Unlike SAstdKt/V, HRs were the lowest in the categories with stdKt/V of 2.40-2.59 and they increased in the higher stdKt/V category. The adjusted HR for SAstdKt/V vs. stdKt/V were 0.68 vs. 0.62 in the category of 2.40-2.59, and 0.63 vs. 0.73 in the category of ≥2.60. The adjusted ORs for anemia progressively decreased as SAstdKt/V increased, whereas ORs decreased to the lowest in stdKt/V category 2.40-2.59 and increased in the ≥2.60 category. The adjusted ORs for hypoalbuminemia progressively decreased as SAstdKt/V and stdKt/V increased which were both 0.45 in 2.40-2.59 category and decreased to 0.29 and 0.42 in the ≥2.60 category.

DISCUSSION

SAstdKt/V is better associated with mortality, anemia, and hypoalbuminemia than stdKt/V. SAstdKt/V is a better parameter in defining hemodialysis dosing which can be calculated by an available online tool. Further studies to determine the optimal SAstdKt/V dose required to achieve improved clinical outcomes with better cost-effectiveness are needed.

Hyporesponsiveness to Anemia Therapy—What are we Doing Wrong?

Most patients receiving anemia therapy respond well, with a significant rise in hemoglobin concentration. However, approximately 5% – 10% of patients fail to show a satisfactory response despite high doses of erythropoietin. The definition of hyporesponsiveness to anemia therapy is somewhat arbitrary, but it is generally regarded as a failure to achieve a hemoglobin concentration of 10 – 11 g/dL despite a dose of erythropoietin in excess of 200 U/kg weekly.

The condition has many causes, the most important ones being iron deficiency, infection or inflammation, and underdialysis. Investigating a patient's poor response to erythropoietin should begin with a check for compliance, followed by screening for iron deficiency. If doubt exists about the presence of iron deficiency, then a trial of intravenous iron may be given.

A reticulocyte count may be helpful. A significantly elevated count suggests the presence of blood loss or hemolysis. The level of C-reactive protein (CRP) may be useful as an indicator of underlying inflammation, and underdialysis may be corrected by increasing the dialysis prescription. If other, minor causes of hyporesponsiveness to erythropoietin have been excluded, then a bone marrow biopsy should be performed. Some patients may require higher doses of erythropoietin, and it is not unreasonable to increase the dose to 10,000 U thrice weekly.

Some causes of hyporesponsiveness to erythropoietin, such as iron deficiency and underdialysis, are easily corrected; but others, such as primary bone marrow disorders and hemoglobinopathies, are not possible to overcome.

Intermediate Outcomes by Race and Ethnicity in Peritoneal Dialysis Patients: Results from the 1997 ESRD Core Indicators Project

Background

Hispanics are the fastest growing minority group in the United States, and approximately 10% of all end-stage renal disease (ESRD) patients are Hispanic. Few data are available, however, regarding dialysis adequacy and anemia management in Hispanic patients receiving peritoneal dialysis in the U.S.

Methods

Data from the Health Care Financing Administration (HCFA) ESRD Core Indicators Project were used to assess racial and ethnic differences in selected intermediate outcomes for peritoneal dialysis patients.

Results

Of the 1219 patients for whom data were available from the 1997 sample, 9% were Hispanic, 24% were non-Hispanic blacks, and 59% were non-Hispanic whites. Hispanics were more likely to have diabetes mellitus as a cause of ESRD compared to blacks or whites, and both Hispanics and blacks were younger than white patients (both p < 0.001). Although whites had higher weekly Kt/V and creatinine clearance values compared to blacks or Hispanics ( p < 0.05), blacks had been dialyzing longer ( p < 0.01) and were more likely to be anuric compared to the other two groups ( p < 0.001). Blacks had significantly lower mean hematocrit values ( p < 0.001) and a greater proportion of patients who had a hematocrit level less than 28% ( p < 0.05) compared to Hispanics or whites, despite receiving significantly larger weekly mean epoetin alfa doses ( p < 0.05) and having significantly higher mean serum ferritin concentrations ( p < 0.01). Multivariate logistic regression analysis revealed significant differences by race/ethnicity for experiencing a weekly Kt/V urea < 2.0 and hypertension, but not for other intermediate outcomes examined (weekly creatinine clearance < 60 L/week/1.73 m2, Hct < 30%, and serum albumin < 3.5/3.2 g/dL).

Conclusion

Hispanics had adequacy values similar to blacks and anemia parameters similar to whites. Additional studies are needed to determine the etiologies of the differences in intermediate outcomes by racial and ethnic groupings in peritoneal dialysis patients.

Restitution volumes at the end of dialysis sessions: A potential influencing factor on patients' haemoglobin levels?

AIM

To evaluate whether haemoglobin (Hb) levels are influenced by the restitution volume (RestVol) at the end of the dialysis session, independently of erythropoiesis-stimulating agents (ESA) and iron doses.

DESIGN

Over 12 months, 4,386 haemodialysis patients from 34 centres were enrolled in this observational descriptive study according to the checklist STrengthening the Reporting of Observational Studies in Epidemiology (STROBE).

METHOD

RestVol, Hb levels, ESA and iron doses of every patient were assessed on a monthly basis. To determine the ideal RestVol, the clinics were classified into three groups according to the restitution volumes at the end of the dialysis sessions.

RESULTS

Mean age was 69 ± 14 years, and 58.9% were men. The evaluation of 665,712 treatments revealed that RestVol of 380 ml seems to be the most efficient, since the clinics in this group managed to reduce ESA consumption with a negligible reduction in Hb levels.

Obesity may be erythropoietin dose-saving in hemodialysis patients

Background

In dialysis patients, the obesity-survival paradox still requires an explanation. Anemia and high doses of erythropoiesis-stimulating agents (ESAs) are associated with worse outcomes in the hemodialysis (HD) population. In the present study, we explored the relation between obesity and anemia control in a sample of maintenance HD patients in Egypt.

Methods

This multicenter observational study included 733 patients on maintenance HD from 9 hemodialysis centers in Egypt. Clinical and laboratory data as well as average doses of ESAs and parenteral iron were recorded. The erythropoietin resistance index (ERI) was calculated.

Results

Obesity, defined as a body mass index (BMI) ≥ 30 kg/m², was present in 22.6% of the studied population. The target hemoglobin level (10.0–11.5 g/dL) was achieved in 27.3% of non-obese and 25.3% of obese patients, with no significant difference. The median serum ferritin and the values of transferrin saturation index did not differ significantly between these two groups. The weekly ESA dose was significantly lower in obese than in non-obese patients (P = 0.0001). A trend toward higher ESA doses and ERI values was observed in patients with lower BMIs (P < 0.0001). Multiple linear regression revealed that the BMI and urea reduction ratio were the strongest predictors of the ERI.

Conclusion

Our study adds more evidence to obesity-associated advantages in HD patients. BMI may determine ESA response, with better responses observed in patients with higher BMIs.

Association between serum hepcidin-25 and primary resistance to erythropoiesis-stimulating agents in chronic kidney disease: a secondary analysis of the HERO trial

BACKGROUND

Pentoxifylline has been shown to increase haemoglobin levels in patients with chronic kidney disease (CKD) and erythropoietin-stimulating agent (ESA)-hyporesponsive anaemia in the Handling Erythropoietin Resistance with Oxpentifylline multicentre double-blind, randomized controlled trial. The present sub-study evaluated the effects of pentoxifylline on the iron-regulatory hormone hepcidin in patients with ESA-hyporesponsive CKD.

METHODS

This sub-study included 13 patients in the pentoxifylline arm (400 mg daily) and 13 in the matched placebo arm. Hepcidin-25 was measured by ultra performance liquid chromatography/quadrupole time-of-flight mass spectrometry following isolation from patient serum. Serum hepcidin-25, serum iron biomarkers, haemoglobin and ESA dosage were compared within and between the two groups.

RESULTS

Hepcidin-25 concentration at 4 months adjusted for baseline did not differ significantly in pentoxifylline versus placebo treated patients (adjusted mean difference (MD) -7.9 nmol, P = 0.114), although the difference between the groups mean translated into a >25% reduction of circulating hepcidin-25 due to pentoxifylline compared with the placebo baseline. In paired analysis, serum hepcidin-25 levels were significantly decreased at 4 months compared with baseline in the pentoxifylline group (-5.47 ± 2.27 nmol/l, P < 0.05) but not in the placebo group (2.82 ± 4.29 nmol/l, P = 0.24). Pentoxifylline did not significantly alter serum ferritin (MD 55.4 mcg/l), transferrin saturation (MD 4.04%), the dosage of ESA (MD -9.93 U/kg per week) or haemoglobin concentration (MD 5.75 g/l).

CONCLUSION

The reduction of circulating hepcidin-25 due to pentoxifylline did not reach statistical significance; however, the magnitude of the difference suggests that pentoxifylline may be a clinically and biologically meaningful modulator of hepcidin-25 in dialysis of patients with ESA-hyporesponsive anaemia.

The Effect of Hemodialysis and Acetate-Free Biofiltration on Anemia

The authors monitored, for a period of 12 months, anemia-, nutrition-, and free radical-related parameters and the rHuEPO dose required to maintain target hemoglobin (Hb) in 20 patients with chronic renal failure. Ten patients each were randomized for treatment by either acetate-free biofiltration (AFB) or low-flux hemodialysis (HD). At baseline, Hb levels were 102±2 (AFB) vs. 98±2 g/L (HD) (not significant difference, NS), the rHuEPO dose was 4050±976 vs. 5100±1538 IU/week (NS). Compared with baseline and with HD, lower rHuEPO doses were required during AFB at months 8, 9, 10 and 11, and 12 when they were 2100±510 (AFB) vs. 6000±1153 (HD), p=0.008. Prealbumin, transferrin and cholinesterase levels rose in the AFB group. Kt/V, albumin, transferrin saturation, aluminium, bicarbonate in serum, superoxide dismutase and glutathione peroxidase in erythrocytes, and malondialdehyde and antioxidant capacity in plasma did not differ between the AFB and HD groups. In terms of anemia control, AFB using an AN69 membrane was found to be more advantageous than low-flux HD, AFB improves some nutritional parameters. The compared methods do not differ in their effect on lipid peroxidation and the antioxidant system. (Int J Artif Organs 2000; 23: 173–80)

Improving Erythropoiesis Stimulating Agent Hyporesponsiveness in Hemodialysis Patients: The Role of Hepcidin and Hemodiafiltration Online

Hyporesponsiveness to erythropoietin stimulating agents (ESAs) is a condition associated with increased mortality. Even after identifying the condition, the causes are difficult to treat and only partially reversible in end-stage renal disease patients. Thus, the role of more recent hemodialysis (HD) techniques in improving such conditions is an emerging issue. However, major randomized clinical trials have not confirmed the results of smaller observational studies in which online hemodiafiltration has shown some efficacy in improving patients' response to ESAs. In our interpretation, these findings are not in contrast, but they can be explained by a better understanding of the interactions between HD and ESAs on iron mobilization, first of all through the role of hepcidin. The kinetics of hepcidin removal through HD combined with the action of selected ESAs may help the clinician in prescribing the best association between HD treatment and ESAs to overcome hyporesponsiveness.

Shorter dialysis session length was not associated with lower mental health and physical functioning in elderly hemodialysis patients: Results from the Japan Dialysis Outcome and Practice Patterns Study (J-DOPPS)

Background

Health-related quality of life (HRQOL) is often prioritized over long-term survival in elderly patients. Although a longer dialysis session length (DSL) has been shown to reduce mortality, its effects on improving the HRQOL are unknown.

Methods

Using data from the Japan Dialysis Outcomes and Practice Patterns Study (J-DOPPS), patients aged ≥ 65 years on maintenance hemodialysis were enrolled. DSL was categorized as short (<210 minutes), medium (210–240 minutes), or long (>240 minutes). The primary outcomes were changes in mental health (ΔMH) and physical functioning (ΔPF) scores assessed using the Japanese version of SF-12, in one year. The differences in the ΔMH and ΔPF among the three groups were assessed via regression (beta) coefficients derived using a linear regression model.

Results

Of 1,187 patients at baseline, 319 (26.9%) had a short length, 686 (57.8%) a medium length, and 182 (15.3%) a long length. We assessed the ΔMH data from 793 patients and the ΔPF data from 738. No significant differences in the ΔMH were noted for the short or long groups compared with the medium group (score difference: 0.26, 95% confidence interval [CI]: -4.17 to 4.69 for short; score difference: -1.15, 95% CI: -6.17 to 3.86 for long). Similarly, no significant differences were noted for these groups versus the medium group in ΔPF either (score difference: -1.43, 95% CI: -6.73 to 3.87 for short; score difference: -1.71, 95% CI: -7.63 to 4.22 for long).

Conclusions

A shorter DSL might have no adverse effects on MH or PF for elderly patients.

Impact of gender and dialysis adequacy on anaemia in peritoneal dialysis

Purpose

In the general population, haemoglobin (Hb) concentration is higher in men than in women. However, target Hb levels in dialysis patients are set constant regardless of the patient’s sex. The aim of this study was to evaluate Hb concentration and the use of erythropoiesis-stimulating agents (ESA) in peritoneal dialysis (PD) patients taking gender and dialysis adequacy into account.

Methods

The study comprised two parts. The first was a cross-sectional analysis of Hb and ESA in 2180 prevalent PD patients. The second included 88 incident PD patients, followed for 36 months. During this time, the major parameters recorded at 12-month intervals included: Hb concentration, weekly ESA, total, renal, and peritoneal Kt/V. Erythropoietin resistance index (ERI) was calculated as the ratio between ESA dose and achieved Hb.

Results

In prevalent PD patients, Hb concentration was significantly lower in women, (11.2 ± 1.4 vs. 11.5 ± 1.6 g/dl; p < 0.001), despite higher doses of ESA (2691 ± 1821 vs. 2344 ± 1422; p = 0.001). Hb concentrations were related to dialysis adequacy in both cohorts. However, despite significantly higher Kt/V, women were characterized by a lower Hb level. In incident patients, this association was present throughout the observation period, while the ESA dose in women was significantly higher at every time point. In multiple regression analysis, gender was an independent determinant of ERI (b = 0.34; p < 0.05).

Conclusions

Despite higher dialysis adequacy, Hb concentration in women treated with PD is significantly lower, and the ability to correct it impaired, as compared to men.

Dynamics of the erythropoiesis stimulating agent resistance index in incident hemodiafiltration and high-flux hemodialysis patients

Hyporesponsiveness to erythropoiesis-stimulating agent therapy in dialysis patients is poorly understood. Some studies report an improvement in the erythropoiesis-stimulating agent resistance index (ERI) with hemodiafiltration (HDF) versus high-flux hemodialysis (HD). We explored ERI dynamics in 38,340 incident HDF and HD patients treated in 22 countries over a 7-year period. Groups were matched by propensity score at baseline (6 months after dialysis initiation). The follow-up period (mean of 1.31 years) was stratified into 1 month intervals with delta analyses performed for key ERI-related parameters. Dialysis modality, time interval, and polycystic kidney disease were included in a linear mixed model with the outcome ERI. Baseline ERI was nonsignificantly higher in HDF versus HD treatment. ERI decreased significantly faster in HDF-treated patients than in HD-treated patients, was decreased in both HD and HDF when patients were treated with intravenous darbepoetin alfa, but only in HDF when treated with intravenous recombinant human erythropoietin (rHuEPO). A clear difference between HD- and HDF-treated patients could only be found for patients with high baseline ERI and assigned to intravenous rHuEPO treatment. A significant advantage in terms of lower ERI for patients treated by HDF was found. Sensitivity analysis limited this advantage for HDF to those patients treated with intravenous rHuEPO (not darbepoetin alfa or subcutaneous rHuEPO) and to patients with a high baseline ERI. Thus, our results allow more accurate planning for future clinical trials addressing anemia management in dialysis patients.

Adequate hemodialysis improves anemia by enhancing glucose-6-phosphate dehydrogenase activity in patients with end-stage renal disease

Background

We conducted this study to determine the erythrocyte glucose-6-phosphate dehydrogenase (G6PD) activity level in patients with end-stage renal disease (ESRD) on maintenance hemodialysis (HD) and to determine the effect of hemodialysis adequacy on G6PD activity levels and its impact on anemia.

Methods

Eighty-two patients (48 men and 34 women) receiving regular hemodialysis for ESRD through arteriovenous fistulae for at least one year prior to the start of the study were enrolled in this study. G6PD activity levels were measured in all patients and the average Kt/V was used as a parameter of HD adequacy. Patients were divided into two groups according to Kt/V values. Group 1 included 45 patients with Kt/V˃1.2 (adequate HD), and group 2 included 37 patients with Kt/V˃1.2 (inadequate HD). The average hemoglobin level and the weekly dose of an erythropoietin-stimulating agent, epoetin alpha (ESA), for each patient were calculated for one year.

Results

The mean (SD) erythrocyte G6PD activity for all patients on hemodialysis was 7.64 ± 1.85 U/g Hb. Patients who had received adequate hemodialysis had a significantly higher average erythrocyte G6PD (mean (SD) = 9.2 ± 0.7 U/g Hb) compared to patients who had inadequate hemodialysis (mean (SD) = 5.7 ± 0.7U/g Hb) (P-value <0.005). The mean hemoglobin concentration was significantly higher in patients with adequate hemodialysis compared to those with inadequate hemodialysis.

Conclusion

Our study demonstrated the beneficial effect of adequate hemodialysis in correcting anemia by enhancing the erythrocyte G6PD activity in patients.

Safety and Efficacy of PDpoetin for Management of Anemia in Patients with end Stage Renal Disease on Maintenance Hemodialysis: Results from a Phase IV Clinical Trial

Recombinant human erythropoietin (rHuEPO) is available for correcting anemia. PDpoetin, a new brand of rHuEPO, has been certified by Food and Drug Department of Ministry of Health and Medical Education of Iran for clinical use in patients with chronic kidney disease. We conducted this post-marketing survey to further evaluate the safety and efficacy of PDpoetin for management of anemia in patients on maintenance hemodialysis. Patients from 4 centers in Iran were enrolled for this multicenter, open-label, uncontrolled phase IV clinical trial. Changes in blood chemistry, hemoglobin and hematocrit levels, renal function, and other characteristics of the patients were recorded for 4 months; 501 of the patients recruited, completed this study. Mean age of the patients was 50.9 (±16.2) years. 48.7% of patients were female. Mean of the hemoglobin value in all of the 4 centers was 9.29 (±1.43) g/dL at beginning of the study and reached 10.96 (±2.23) g/dL after 4 months and showed significant increase overall (P<0.001). PDpoetin dose was stable at 50-100 U/kg thrice weekly. Hemorheologic disturbancesand changes in blood electrolytes was not observed. No case of immunological reactions to PDpoetin was observed. Our study, therefore, showed that PDpoetin has significantly raised the level of hemoglobin in the hemodialysis patients (about 1.7±0.6 g/dL). Anemia were successfully corrected in 49% of patients under study. Use of this biosimilar was shown to be safe and effective for the maintenance of hemoglobin in patients on maintenance hemodialysis.

Two-times weekly hemodialysis in China: frequency, associated patient and treatment characteristics and Quality of Life in the China Dialysis Outcomes and Practice Patterns study

BACKGROUND

Renal replacement therapy is rapidly expanding in China, and two-times weekly dialysis is common, but detailed data on practice patterns are currently limited. Using cross-sectional data from the China Dialysis Outcomes and Practice Patterns Study (DOPPS), we describe the hemodialysis practice in China compared with other DOPPS countries, examining demographic, social and clinical characteristics of patients on two-times weekly dialysis.

METHODS

The DOPPS protocol was implemented in 2011 among a cross-section of 1379 patients in 45 facilities in Beijing, Guangzhou and Shanghai. Data from China were compared with a cross section of 11 054 patients from the core DOPPS countries (collected 2009-11). Among China DOPPS patients, logistic and linear regression were used to describe the association of dialysis frequency with patient and treatment characteristics and quality of life.

RESULTS

A total of 26% of the patients in China were dialyzing two times weekly, compared with < 5% in other DOPPS regions. Standardized Kt/V was lowest in China (2.01) compared with other regions (2.12-2.27). Female sex, shorter dialysis vintage, lower socioeconomic status, less health insurance coverage, and lack of diabetes and hypertension were associated with dialyzing two times weekly (versus three times weekly). Patients dialyzing two times per week had longer treatment times and lower standardized Kt/V, but similar quality of life scores.

CONCLUSIONS

Two-times weekly dialysis is common in China, particularly among patients, who started dialysis more recently, have a lower comorbidity burden and have financial constraints. Quality of life scores do not differ between the two-times and three-times weekly groups. The effect on clinical outcomes merits further study.

Optimization of anemia treatment in hemodialysis patients via reinforcement learning

OBJECTIVE

Anemia is a frequent comorbidity in hemodialysis patients that can be successfully treated by administering erythropoiesis-stimulating agents (ESAs). ESAs dosing is currently based on clinical protocols that often do not account for the high inter- and intra-individual variability in the patient's response. As a result, the hemoglobin level of some patients oscillates around the target range, which is associated with multiple risks and side-effects. This work proposes a methodology based on reinforcement learning (RL) to optimize ESA therapy.

METHODS

RL is a data-driven approach for solving sequential decision-making problems that are formulated as Markov decision processes (MDPs). Computing optimal drug administration strategies for chronic diseases is a sequential decision-making problem in which the goal is to find the best sequence of drug doses. MDPs are particularly suitable for modeling these problems due to their ability to capture the uncertainty associated with the outcome of the treatment and the stochastic nature of the underlying process. The RL algorithm employed in the proposed methodology is fitted Q iteration, which stands out for its ability to make an efficient use of data.

RESULTS

The experiments reported here are based on a computational model that describes the effect of ESAs on the hemoglobin level. The performance of the proposed method is evaluated and compared with the well-known Q-learning algorithm and with a standard protocol. Simulation results show that the performance of Q-learning is substantially lower than FQI and the protocol. When comparing FQI and the protocol, FQI achieves an increment of 27.6% in the proportion of patients that are within the targeted range of hemoglobin during the period of treatment. In addition, the quantity of drug needed is reduced by 5.13%, which indicates a more efficient use of ESAs.

CONCLUSION

Although prospective validation is required, promising results demonstrate the potential of RL to become an alternative to current protocols.

Determinants of hemoglobin variability in stable peritoneal dialysis patients

PURPOSE

Significant within-patient hemoglobin (Hb) level variability is well recognized in particularly hemodialysis patients. Several factors such as hospitalizations, intercurrent diseases and IV iron therapy are found to be related to Hb variability (Hb-var). In this observational study, we aimed to identify predictors and outcome of Hb-var in peritoneal dialysis (PD) patients without hospitalization, intercurrent disease and IV iron therapy during the study period.

METHODS

All patients were in the maintenance phase of short-acting erythropoiesis-stimulating agents (ESAs) therapy. The target range of Hb was 11-12 g/dL according to KDOQI Guidelines in 2007. The desired range of Hb was 11-12.5 g/dL. Patients' demographic and laboratory data were collected at baseline. Atherosclerotic disease was assessed using carotid intima-media thickness (CIMT). We assessed Hb variability with various methods using SD Hbmean, SD Hbrange and the velocity of Hb change. Hb deflectpositive, Hb deflectnegative, Hb values and ESA dosing were recorded monthly for 6 months.

RESULTS

This study included 50 prevalent PD patients (mean age 46.9 ± 13.7 years, 25 women). The mean velocity of Hb change was negatively correlated with age and positively correlated with frequent ESA dose changes. Higher albumin and residual renal function (RRF) were also positively correlated with Hb deflectpositive. Patients with CIMT ≥0.7 cm had lower SD Hb range compared to CIMT <0.7 cm. Cumulative survival was better in patients with Hb levels consistently ≥10 g/dL compared to patients who had Hb <10 g/dL for at least 1 month. However, Hb-var was not associated with mortality.

CONCLUSIONS

In PD patients without hospitalization, intercurrent disease(s) or IV iron therapy, young age, higher albumin or RRF and lower CIMT were associated with greater oscillations in response to ESA therapy. Careful and appropriate ESA dose changes considering these parameters could minimize Hb variability in these patients.

Erythropoiesis-stimulating agents in chronic kidney disease: what have we learned in 25 years?

Since the pioneering studies by Eschbach et al in 1987, erythropoiesis-stimulating agents (ESAs) have become the mainstay of anemia therapy in chronic kidney disease (CKD) patients. The introduction of ESAs 25 years ago markedly improved the lives of many patients with CKD, who until then had severe, often transfusion-dependent anemia. However, randomized controlled trials demonstrate an increased risk for cardiovascular events such as stroke, thrombosis, and death at nearly normal hemoglobin concentrations and higher ESA doses in CKD. By contrast, kidney transplant recipients may represent a unique population of CKD patients who may benefit from ESA therapy. This review discusses potential mechanisms involving the erythropoietic and nonerythropoietic effects of ESA treatment and ESA resistance. Further research aimed at elucidating the causal pathways is strongly recommended. Given current knowledge, however, clinical practice should avoid disproportionately high dosages of ESAs to achieve recommended hemoglobin targets, particularly in those with significant cardiovascular morbidity or ESA resistance. The key to CKD anemia management will be individualization of the potential benefits of reducing blood transfusions and anemia-related symptoms against the risks of harm.

Carbamylation of serum albumin and erythropoietin resistance in end stage kidney disease

BACKGROUND AND OBJECTIVES

The mechanisms underlying erythropoietin resistance are not fully understood. Carbamylation is a post-translational protein modification that can alter the function of proteins, such as erythropoietin. The hypothesis of this study is that carbamylation burden is independently associated with erythropoietin resistance.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In a nonconcurrent prospective cohort study of incident hemodialysis patients in the United States, carbamylated albumin, a surrogate of overall carbamylation burden, in 158 individuals at day 90 of dialysis initiation and erythropoietin resistance index (defined as average weekly erythropoietin dose [U] per kg body weight per hemoglobin [g/dl]) over the subsequent 90 days were measured. Linear regression was used to describe the relationship between carbamylated albumin and erythropoietin resistance index. Logistic regression characterized the relationship between erythropoietin resistance index, 1-year mortality, and carbamylation.

RESULTS

The median percent carbamylated albumin was 0.77% (interquartile range=0.58%-0.93%). Median erythropoietin resistance index was 18.7 units/kg per gram per deciliter (interquartile range=8.1-35.6 units/kg per gram per deciliter). Multivariable adjusted analysis showed that the highest quartile of carbamylated albumin was associated with a 72% higher erythropoietin resistance index compared with the lowest carbamylation quartile (P=0.01). Increasing erythropoietin resistance index was associated with a higher risk of death (odds ratio per unit increase in log-erythropoietin resistance index, 1.69; 95% confidence interval, 1.06 to 2.70). However, the association between erythropoietin resistance index and mortality was no longer statistically significant when carbamylation was included in the analysis (odds ratio, 1.44; 95% confidence interval, 0.87 to 2.37), with carbamylation showing the dominant association with death (odds ratio for high versus low carbamylation quartile, 4.53; 95% confidence interval, 1.20 to 17.10).

CONCLUSION

Carbamylation was associated with higher erythropoietin resistance index in incident dialysis patients and a better predictor of mortality than erythropoietin resistance index.

Reticulocyte dynamic and hemoglobin variability in hemodialysis patients treated with Darbepoetin alfa and C.E.R.A.: a randomized controlled trial

Background

In a simulation based on a pharmacokinetic model we demonstrated that increasing the erythropoiesis stimulating agents (ESAs) half-life or shortening their administration interval decreases hemoglobin variability. The benefit of reducing the administration interval was however lessened by the variability induced by more frequent dosage adjustments. The purpose of this study was to analyze the reticulocyte and hemoglobin kinetics and variability under different ESAs and administration intervals in a collective of chronic hemodialysis patients.

Methods

The study was designed as an open-label, randomized, four-period cross-over investigation, including 30 patients under chronic hemodialysis at the regional hospital of Locarno (Switzerland) in February 2010 and lasting 2 years. Four subcutaneous treatment strategies (C.E.R.A. every 4 weeks Q4W and every 2 weeks Q2W, Darbepoetin alfa Q4W and Q2W) were compared with each other. The mean square successive difference of hemoglobin, reticulocyte count and ESAs dose was used to quantify variability. We distinguished a short- and a long-term variability based respectively on the weekly and monthly successive difference.

Results

No difference was found in the mean values of biological parameters (hemoglobin, reticulocytes, and ferritin) between the 4 strategies. ESAs type did not affect hemoglobin and reticulocyte variability, but C.E.R.A induced a more sustained reticulocytes response over time and increased the risk of hemoglobin overshooting (OR 2.7, p = 0.01). Shortening the administration interval lessened the amplitude of reticulocyte count fluctuations but resulted in more frequent ESAs dose adjustments and in amplified reticulocyte and hemoglobin variability. Q2W administration interval was however more favorable in terms of ESAs dose, allowing a 38% C.E.R.A. dose reduction, and no increase of Darbepoetin alfa.

Conclusions

The reticulocyte dynamic was a more sensitive marker of time instability of the hemoglobin response under ESAs therapy. The ESAs administration interval had a greater impact on hemoglobin variability than the ESAs type. The more protracted reticulocyte response induced by C.E.R.A. could explain both, the observed higher risk of overshoot and the significant increase in efficacy when shortening its administration interval.

Trial registration

ClinicalTrials.gov: NCT01666301

Effect of ethnicity on erythropoietin therapy response for hemodialysis patients: a retrospective study

Anemia is a common feature in chronic kidney disease patients due to deficiency of erythropoietin (EPO). Diseased kidneys are unable to produce EPO, which enhances red blood cell production from the bone marrow. Recombinant human EPO in hemodialysis patients was introduced with perfect outcomes as a hormonal substitutive treatment. Some ethnic minority groups have high prevalence of anemia associated with chronic kidney diseases. The aim of this study is to evaluate the differences between African Caribbeans and Caucasians' EPO therapy response with regard to hemoglobin (Hb), some factors affecting it and some comorbid conditions. A retrospective study for 6 months of 100 patients on hemodialysis was conducted on two ethnic minorities groups; 46 patients were African Caribbean and 54 patients were Caucasian, who received EPO therapy at once or three times weekly dose at the Hanbury Dialysis Unit of Royal London Hospital. There were three types of EPO therapy used: Aranesp, Mircera and Neorecormon. Forty-six patients were African Caribbean and 54 patients were Caucasian. There were 63.4% of patients treated by Aranesp while 13% were given Mircera; 22.8% of the sample used Neorecorman. It was shown that the chosen comorbid conditions had higher percentage in the African Caribbeans than in Caucasians. Diabetic and/or hypertensive patients are almost double the patient numbers. In addition, sickle cell anemia is only present in African Caribbeans. There were 43.5% of African Caribbeans and 81.1% of Caucasians who met the standards of Hb level. There was no significant difference between African Caribbeans and Caucasians regarding parathyroid hormone, c-reactive protein, B12, mean corpuscular volume, ferritin, and folate. In this study, there was a significant difference in the Hb levels between African Caribbean and Caucasian groups. Sixty percent of African Caribbeans had mean Hb less than normal levels. However, they received lower EPO dose than Caucasians. As a result, this may affect the whole treatment and therapy which may lead to anemic complications.

Predictors of haemoglobin levels and resistance to erythropoiesis-stimulating agents in patients treated with low-flux haemodialysis, haemofiltration and haemodiafiltration: results of a multicentre randomized and controlled trial

Background

Predictors of haemoglobin (Hb) levels and resistance to erythropoiesis-stimulating agents (ESAs) in dialysis patients have not yet been clearly defined. Some mainly uncontrolled studies suggest that online haemodiafiltration (HDF) may have a beneficial effect on Hb, whereas no data are available concerning online haemofiltration (HF). The objectives of this study were to evaluate the effects of convective treatments (CTs) on Hb levels and ESA resistance in comparison with low-flux haemodialysis (HD) and to evaluate the predictors of these outcomes.

Methods

Primary multivariate analysis was made of a pre-specified secondary outcome of a multicentre, open-label, randomized controlled study in which 146 chronic HD patients from 27 Italian centres were randomly assigned to HD (70 patients) or CTs: online pre-dilution HF (36 patients) or online pre-dilution HDF (40 patients).

Results

CTs did not affect Hb levels (P = 0.596) or ESA resistance (P = 0.984). Hb correlated with polycystic kidney disease (P = 0.001), C-reactive protein (P = 0.025), ferritin (P = 0.018), ESA dose (P < 0.001) and total cholesterol (P = 0.021). The participating centres were the main source of Hb variability (partial eta² 0.313, P < 0.001). ESA resistance directly correlated with serum ferritin (P = 0.030) and beta2 microglobulin (P = 0.065); participating centres were again a major source of variance (partial eta² 0.367, P < 0.001). Transferrin saturation did not predict either outcome variables (P = 0.277 and P = 0.170).

Conclusions

In comparison with low-flux HD, CTs did not significantly improve Hb levels or ESA resistance. The main sources of variability were participating centres, ESA dose and the underlying disease.

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

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

Association of ESA hypo-responsiveness and haemoglobin variability with mortality in haemodialysis patients

BACKGROUND

Anaemia is a common complication in dialysis patients. In most cases, it is treated with erythropoietin-stimulating agents (ESA). It is not entirely clear whether the variability of haemoglobin caused by changing ESA response is associated with increased mortality. Therefore, we conducted a retrospective cohort study to evaluate ESA responsiveness and haemoglobin variability in association with mortality.

METHODS

We used the Austrian dialysis and transplant registry, and identified 932 patients who were on maintenance haemodialysis in the years 2005-08 with recorded weekly ESA doses and haemoglobin concentrations. ESA response was defined as a positive regression slope over the observation period. Cox regression analysis with spline functions and purposeful variable selection algorithms were used.

RESULTS

Adjusted Cox regression analysis showed an increased mortality risk in subjects with wide ranges of haemoglobin variability (from <10 to >12 g/dL) (HR = 2.38, 95% CI 1.20-4.71, P = 0.013). Furthermore, patients that never reached haemoglobin levels >10 g/dL despite ESA therapy exhibited the highest risk of mortality (HR = 6.37, 95% CI 2.15-18.82, P < 0.001). ESA hypo-responsiveness was associated with increased risk of mortality in the low as well as high haemoglobin ranges [HR = 2.06, 95% CI 1.49-2.86 at haemoglobin of 9.5 g/dL and HR = 1.64, 95% CI 0.68-3.92 at 13.5 g/dL both vs. 11 g/dL (reference)]. ESA dose equivalents >16,000 units per week were associated with increased mortality in ESA responders (HR = 1.30, 95% CI 1.02-1.64). However, in hypo-responders, mortality is not associated with ESA dose (HR = 1.02, 95% CI 0.87-1.20) [both at weekly ESA dose of 20,000 units vs. 16,000 (reference)].

CONCLUSIONS

These findings suggest that the risk of mortality of haemodialysis patients requiring ESA therapy is lowest if the haemoglobin concentration is stably maintained in the range between 10 and 12 g/dL with weekly ESA dose equivalents <16,000 units.

Hemoglobin variability in patients with chronic kidney disease in the Netherlands

PURPOSE

Hemoglobin cycling has been reported in hemodialysis patients treated with erythropoiesis-stimulating agents (ESA) and is associated with increased mortality. Information on hemoglobin cycling in Europe is limited. We investigated hemoglobin variability in the Netherlands. Hemodialysis and peritoneal dialysis patients were studied and pre-dialysis patients were enrolled.

METHODS

This observational retrospective study was executed in a Dutch dialysis center. We studied 157 patients from 2005 to 2007: 56 hemodialysis, 12 peritoneal dialysis and 29 pre-dialysis patients, all treated with ESA; and 60 pre-dialysis patients without ESA. Patients were divided on the basis of their pattern of hemoglobin fluctuation around a range of 11-12 g/dL. In dialysis patients, the amount of time that hemoglobin remained within that range was calculated. For all patients, the magnitude of hemoglobin fluctuations was assessed (i.e. the difference between hemoglobin maximum and minimum) and data on ESA dose changes and hospitalizations were collected.

RESULTS

None of the ESA treated patients had hemoglobin levels stable within the target range over a one-year period. Pre-dialysis patients without ESA also showed variable hemoglobin levels. A stepwise decrease in the magnitudes of hemoglobin fluctuation was observed in the hemodialysis patients, peritoneal dialysis patients, pre-dialysis patients using ESA, and the pre-dialysis patients without ESA, respectively.

CONCLUSION

In the Netherlands, hemoglobin variability is common in hemodialysis and peritoneal dialysis patients, but also in pre-dialysis patients. The results of this study warrant further research into the relationship between hemoglobin variability and clinical outcomes.

Outcomes associated with in-center nocturnal hemodialysis from a large multicenter program

BACKGROUND AND OBJECTIVES

The objective of this study was to evaluate epidemiology and outcomes of a large in-center nocturnal hemodialysis (INHD) program.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This case-control study compared patients who were on thrice-weekly INHD from 56 Fresenius Medical Care, North America facilities with conventional hemodialysis patients from 244 facilities within the surrounding geographic area. All INHD cases and conventional hemodialysis control subjects who were active as of January 1, 2007, were followed until December 31, 2007, for evaluation of mortality and hospitalization.

RESULTS

As of January 1, 2007, 655 patients had been on INHD for 51 +/- 73 d. Patients were younger, there were more male and black patients, and vintage was longer, but they had less diabetes compared with 15,334 control subjects. Unadjusted hazard ratio was 0.59 for mortality and 0.76 for hospitalization. After adjustment for case mix and access type, only hospitalization remained significant. Fewer INHD patients were hospitalized (48 versus 59%) with a normalized rate of 9.6 versus 13.5 hospital days per patient-year. INHD patients had greater interdialytic weight gains but lower BP. At baseline, hemoglobin values were similar, whereas albumin and phosphorus values favored INHD. Mean equilibrated Kt/V was higher in INHD patients related to longer treatment time, despite lower blood and dialysate flow rates.

CONCLUSIONS

Patients who were on INHD exhibited excellent quality indicators, with better survival and lower hospitalization rates. The relative contributions of patient selection versus effect of therapy on outcomes remain to be elucidated in prospective clinical trials.

Factors that condition the response to erythropoietin in patients on hemodialysis and their relation to mortality

The response to erythropoietin-stimulating agents (ESA) can vary among different patients and according to the different circumstances over time within a given individual. The aim of this study was to analyze the factors that can modify the response to epoetin in patients on hemodialysis (HD) and its influence on early mortality. Prospective and observational study including 1710 patients from 119 HD units in Spain with a follow-up of 12 months. To evaluate the dose-response effect of EPO therapy, we used the erythropoietin resistance index (ERI), calculated as the weekly weight-adjusted dose of EPO divided by the hemoglobin level. Patients were stratified in three groups according to ERI: group A, ERI <5; group B, ERI=5-15; group C, ERI>15 U/kg/week/g per 100 ml. Mean ERI for the entire group was 10.2+/-7.3 U/kg/week/g per 100 ml. ERI was directly related with incident comorbidity (Charlson Index), age, female gender and low body mass index with no relationship with etiology of chronic kidney disease. Patients with antecedents of heart failure, acute infection or malignant neoplasm had significantly higher ERI than those without. Transferrin saturation index, but not serum ferritin, was inversely related with ERI. Serum levels of albumin and cholesterol were related with lower ERI, but no relation was found with normalized protein catabolic rate. Patients with a permanent catheter for HD had significant higher values of ERI than those with native fistula (P=0.012). One year survival in all three groups of patients according to ERI was 0.916 in group A, 0.877 in group B and 0.788 in group C (log-rank=20.7, P<0.001). The resistance to ESA is directly related with incident comorbidity in patients on hemodialysis and it can be interpreted as a useful marker of early mortality.

Hyporesponsiveness to erythropoietin: causes and management

In patients with chronic kidney disease, erythropoietin resistance is common, costly, and has implications beyond the management of anemia because the presence of erythropoietin resistance portends mortal outcomes. Exploring the provenance of erythropoietin resistance may be facilitated by the consideration of the pathogenetic triad of iron-restricted erythropoiesis, inflammation, and bone marrow suppression. Challenging to diagnose because of difficulty in interpreting tests of iron deficiency, iron-restricted erythropoiesis should be considered in patients who require high doses of erythropoietin, have low transferrin saturation (eg, <20%-25%), and do not have very high ferritin (eg, <1,200 ng/mL); a therapeutic trial of intravenous iron may be worthwhile. Aluminum intoxication is a rare cause of iron-restricted erythropoiesis that may manifest as microcytic hypochromic anemia. A decrease in serum albumin concentration may signal the presence of inflammation, which may be manifest (such as because of a recent illness or infection) or occult; the latter include clotted synthetic angioaccess, failed renal allograft, dialysis catheter, periodontal disease, underlying malignancy, or uremia per se. Marrow hyporesponsiveness may be improved by increasing the delivered dialysis dose, using ultrapure dialysate, maintaining adequate vitamin B12 and folate stores, or by treating hyperparathyroidism. In summary, improving the outcomes of erythropoietin-resistant patients will require complete patient assessment that goes beyond considerations of iron and erythropoietin dose alone. Given that erythropoietin dose is associated with mortality, mitigating erythropoietin resistance has the potential to improve patient outcomes.

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.

Nocturnal hemodialysis improves erythropoietin responsiveness and growth of hematopoietic stem cells

Nocturnal home hemodialysis (NHD) is associated with an increase in hemoglobin level. We hypothesized that NHD enhances the removal of toxins of hematopoietic progenitor cells (HPCs), thereby improving HPC growth and function. Among 16 patients with ESRD, 2 mo of NHD nearly doubled Kt/V per session and significantly lowered both parathyroid hormone levels and serum phosphate concentration. In addition, treatment with NHD improved hemoglobin levels from 113 +/- 3 to 125 +/- 4 g/L (P = 0.03) without altering erythropoietin requirements or iron status. To assess whether NHD may enhance removal of HPC toxins, we collected paired plasma samples from the same patient during treatment with conventional HD and NHD. In vitro, growth of erythroid (BFU-E) and granulocytic (CFU-GM) colonies was superior when cultured with NHD plasma compared with conventional HD plasma. Differential gene expression profiles obtained from peripheral blood and HPC colonies revealed similar upregulation of genes responsible for HPC mobilization and growth and production of red blood cells. In conclusion, the enhanced clearance by NHD is associated with an improvement in HPC growth and a coordinated increase in expression of genes relevant to production of red blood cells.

[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.

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.

The relationship between dialysis performance measures: adequacy and anemia management

BACKGROUND

Little is known about how urea reduction ratio (URR) and hemoglobin (Hb) level relate as clinical performance measures (CPMs) in dialysis facilities. This study examined the relationship between these CPMs as a reflection of underlying processes.

STUDY DESIGN

Cross-sectional observational.

SETTING & PARTICIPANTS

47,465 records from 18,003 patients dialyzed in 270 End-Stage Renal Disease Network 5 facilities during the final quarter of 2004.

PREDICTOR & OUTCOME

Facility aggregate Hb level and URR, respectively; both expressed as (1) continuous variables and (2) dichotomous indicators based on established quality thresholds.

MEASUREMENTS

Weighted regression analyses were used to determine the: (1) association between CPMs and (2) likelihood of missing the performance threshold for one if also missing the other benchmark.

RESULTS

The association between facility URR and Hb level was minimal, with an adjusted mean increase (beta) in URR of 0.91% +/- 0.38% for each 1-g/dL increment in Hb level (P < 0.0001) and R(2) of 0.02. The adjusted odds ratio of a facility failing to meet the URR quality threshold if missing the Hb level benchmark was 2.08 (P < 0.0001). The C statistic for the associated receiver operator characteristic curve was 0.64, with insignificant change when including Hb performance as a predictor of URR performance.

LIMITATIONS

Inability to incorporate historic performance or ascertain facility process traits that influence CPMs.

CONCLUSIONS

There was minimal association between facility URR and Hb level. The limited concordance in facility performance for these CPMs points to distinct processes that determine quality for each.

Erythropoiesis-stimulating agent hyporesponsiveness

Approximately 5-10% of patients with chronic kidney disease demonstrate hyporesponsiveness to erythropoiesis-stimulating agents (ESA), defined as a continued need for greater than 300 IU/kg per week erythropoietin or 1.5 mug/kg per week darbepoetin administered by the subcutaneous route. Such hyporesponsiveness contributes significantly to morbidity, mortality and health-care economic burden in chronic kidney disease and represents an important diagnostic and management challenge. The commonest causes of ESA resistance are non-compliance, absolute or functional iron deficiency and inflammation. It is widely accepted that maintaining adequate iron stores, ideally by administering iron parenterally, is the most important strategy for reducing the requirements for, and enhancing the efficacy of ESA. There have been recent epidemiologic studies linking parenteral iron therapy to an increased risk of infection and atherosclerosis, although other investigations have refuted this. Inflammatory ESA hyporesponsiveness has been reported to be improved by a number of interventions, including the use of biocompatible membranes, ultrapure dialysate, transplant nephrectomy, ascorbic acid therapy, vitamin E supplementation, statins and oxpentifylline administration. Other variably well-established causes of ESA hyporesponsiveness include inadequate dialysis, hyperparathyroidism, nutrient deficiencies (vitamin B12, folate, vitamin C, carnitine), angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, aluminium overload, antibody-mediated pure red cell aplasia, primary bone marrow disorders, myelosuppressive agents, haemoglobinopathies, haemolysis and hypersplenism. This paper reviews the causes of ESA hyporesponsiveness and the clinical evidence for proposed therapeutic interventions. A practical algorithm for approaching the investigation and management of patients with ESA hyporesponsiveness is also provided.