Prevalence of anemia in erythropoietin-treated pediatric as compared to adult chronic dialysis patients

Use of erythropoiesis-stimulating agents in children with chronic kidney disease: a systematic review

Background

Erythropoiesis-stimulating agents (ESAs) revolutionized the management of anaemia in chronic kidney disease (CKD) when introduced in the late 1980s. A range of ESA types, preparations and administration modalities now exist, with newer agents requiring less frequent administration. Although systematic reviews and meta-analyses have been published in adults, no systematic review has been conducted investigating ESAs in children.

Methods

The Preferred Reporting Items for Systematic Reviews and Meta-analyses statement for the conduct of systematic reviews was used. All available literature on outcomes relating to ESAs in children with CKD was sought. A search of the MEDLINE, CINAHL and Embase databases was conducted by two independent reviewers. Inclusion criteria were published trials in English, children with chronic and end-stage kidney disease and use of any ESA studied against any outcome measure. An assessment of risk of bias was carried out in all included randomized trials using the criteria from the Cochrane Handbook for Systematic Reviews of Interventions. Two tables were used for data extraction for randomized and observational studies. Study type, participants, inclusion criteria, case characteristics, follow-up duration, ESA type and dosage, interventions and outcomes were extracted by one author.

Results

Of 965 identified articles, 58 were included covering 54 cohorts. Six were randomized trials and 48 were observational studies. A total of 38 studies assessed the efficacy of recombinant human erythropoietin (rHuEPO), 11 of darbepoetin alpha (DA) and 3 of continuous erythropoietin receptor activator (CERA), with 6 studies appraising secondary outcome measures exclusively. Recruitment to studies was a consistent challenge. The most common adverse effect was hypertension, although confounding effects often limited direct correlation. Two large cohort studies demonstrated a greater hazard of death independently associated with high ESA dose. Secondary outcome measures included quality of life measures, growth and nutrition, exercise capacity, injection site pain, cardiovascular function, intelligent quotient, evoked potentials and platelet function.

Conclusions

All ESA preparations and modes of administration were efficacious, with evidence of harm at higher doses. Evidence supports individualizing treatments, with strong consideration given to alternate treatments in patients who appear resistant to ESA therapy. Further research should focus on randomized trials comparing the efficacy of different preparations, treatment options in apparently ESA-resistant cohorts and clarification of meaningful secondary outcomes to consolidate patient-relevant indices.

Evaluation of renal replacement therapy in children and adolescents in the state of Amazonas, Brazil

Abstract Objective: To describe the characteristics of stage-5 chronic kidney disease (CKD) children and adolescents undergoing renal replacement therapy (RRT) in Amazonas, Brazil, estimating the frequencies of current and new cases, describing the presence of anemia and bone metabolism disorders. Methods: Thirty-five patients aged 7 to 19 years-old on hemodialysis (HD) or peritoneal dialysis (PD) were studied between June 2018 and April 2019. The frequencies of current and new cases were estimated based on the 0 to 19 years-old population of Amazonas, in the same period. Data were collected about the underlying cause and diagnosis of CKD, dialysis, and biochemical analysis. Results: The frequencies of current and new cases were 24 and 15 patients per million people of compatible age (pmpca), respectively. The causes of CKD were nephrotic syndrome (22.8%), nephritic syndrome (14.3%), and neurogenic bladder (14.3%); in 48.6%, the cause was unknown/not investigated. Ten patients underwent renal biopsy, seven with segmental and focal glomerulosclerosis. The majority (80%) were on HD, with an average kt/V of 1.4, and in 51.4% the vascular access was the double lumen catheter. Hypocalcemia was found in 82.8% of patients, hyperphosphatemia in 57.2%, vitamin D insufficiency or deficiency in 60%, and altered parathyroid hormone values in 48.6%. Hemoglobin was low in 80%, with absolute/functional iron deficiency in 28.6%. Conclusions: In children and adolescents of Amazonas, Brazil, we found 24 pmpca with stage-5 CKU currently in RRT and 16.3 pmpca per year of new cases requiring RRT. Most patients were adolescents on HD, half without a causal diagnosis of CKD, with a high frequency of anemia and bone metabolism disorder.

The Role of Reticulocyte Hemoglobin Content for the Diagnosis of Functional Iron Deficiency in Hemodialyzed patients

The effectiveness of reticulocyte hemoglobin content (CHr) had been reported to detect early functional iron deficiency especially among Chronic kidney disease (CKD) patients. CHr is more superior to classic biochemical indices in reflecting transient iron-deficiency status, therefore improving diagnosis and treatment. This study was conducted to determine the sensitivity of CHr in the diagnosis of functional iron deficiency (FID) in hemodialyzed patients. One hundred hemodialyzed patients along with 60 healthy controls were recruited and blood specimens were collected. Venous blood was used for hematological and biochemical investigations collected via 3 ml lavender-top tubes for hematological tests including CBC, blood film, ESR and CHr, and red-top tube for biochemical tests including TIBC, SF and CRP. A statistically significant decrease was noted in CHr values between hemodialysis patients and the control group (24.8 ± 2.0 pg vs. 30.9 ± 1.3 pg, p<0.001). CHr values showed a significant correlations with RBCs, Hb- hemoglobin, Hct- hematocrit level, MCV- mean corpuscular volume, MCH- mean corpuscular hemoglobin, MCHC, RDW- red cell distribution width , SI-Serum Iron, TIBC- Total iron binding capacity and TSAT- Transferrin saturation. The present study showed that CHr in comparison to the conventional hematological and biochemical markers commonly used to diagnose iron deficiency.

Anemia and Iron Deficiency in Children with Chronic Kidney Disease (CKD): Data from the Know-Ped CKD Study

Children with chronic kidney disease (CKD) are at high risk of anemia, an important risk factor for cardiovascular disease and poor quality of life. The present study used baseline data from the Korean cohort study for Outcome in patients With Pediatric Chronic Kidney Disease (KNOW-PedCKD). A Total of 437 patients was included in the analyses excluding missing data. The characteristics of patients with and without anemia and those of patients with and without iron deficiency were compared. Logistic regression analysis and Pearson correlation were conducted to evaluate associated risk factors and correlations in children with CKD. Anemia in children with CKD was associated with older age, low body weight and body mass index (BMI) z-score, birth age, preceding glomerulonephritis, decreased estimated glomerular filtration rate (eGFR), low levels of serum albumin and calcium, high levels of serum intact parathyroid hormone (iPTH), and serum phosphorus. Anemia was correlated positively with changes in the BMI z-score, body weight, and serum albumin and cholesterol levels, but correlated negatively with serum calcium, iPTH, ferritin levels, and transferrin saturation. Iron deficiency in children with CKD was associated with young age, low hemoglobin and serum ferritin levels, high BMI z-scores, and low levels of serum iPTH. This is the first nationwide cohort study of anemia in Korean children with CKD and the first prospective pediatric CKD cohort study in Asia. The study results demonstrated that anemia and iron deficiency are affected by various factors, including age, BMI, and levels of serum iPTH. To improve the retrospective outcome of affected children, it is important to understand the effect of each of these factors and to attempt an early intervention to prevent anemia and iron deficiency by regular measurement of these parameters in children at risk.

Impact of Inflammation on Ferritin, Hepcidin and the Management of Iron Deficiency Anemia in Chronic Kidney Disease

Iron deficiency anemia (IDA) is a major problem in chronic kidney disease (CKD), causing increased mortality. Ferritin stores iron, representing iron status. Hepcidin binds to ferroportin, thereby inhibiting iron absorption/efflux. Inflammation in CKD increases ferritin and hepcidin independent of iron status, which reduce iron availability. While intravenous iron therapy (IIT) is superior to oral iron therapy (OIT) in CKD patients with inflammation, OIT is as effective as IIT in those without. Inflammation reduces predictive values of ferritin and hepcidin for iron status and responsiveness to iron therapy. Upper limit of ferritin to predict iron overload is higher in CKD patients with inflammation than in those without. However, magnetic resonance imaging studies show lower cutoff levels of serum ferritin to predict iron overload in dialysis patients with apparent inflammation than upper limit of ferritin proposed by international guidelines. Compared to CKD patients with inflammation, optimal ferritin levels for IDA are lower in those without, requiring reduced iron dose and leading to decreased mortality. The management of IDA should differ between CKD patients with and without inflammation and include minimization of inflammation. Further studies are needed to determine the impact of inflammation on ferritin, hepcidin and therapeutic strategy for IDA in CKD.

Comparison of reticulocyte hemoglobin equivalent with traditional markers of iron and erythropoiesis in pediatric dialysis

BACKGROUND

Anemia is a major complication for patients on chronic dialysis. Erythropoietin is effective if iron is available, however unnecessary iron supplementation results in iron overload. Reticulocyte hemoglobin equivalent (Ret-He) may be useful for assessing iron status.

METHODS

A national retrospective cohort study including all children on chronic dialysis in New Zealand between 2007 and 2013, pairing Ret-He with demographic information, anemia indices, and markers of iron status.

RESULTS

In 606 observations, we found a modest relationship between Ret-He and transferrin saturation (TSAT) (r = 0.34, p < 0.001) and a poor correlation between Ret-He and ferritin (r = 0.09, p = 0.04). There was a negative correlation between ferritin and hemoglobin (r = -0.14, p = 0.002), a weak positive correlation between TSAT and hemoglobin (r = 0.12, p = 0.007), and a modest positive correlation between Ret-He and hemoglobin (r = 0.22, p < 0.001). The diagnostic performance of Ret-He to detect absolute iron deficiency (cut-off value 28.9 pg, sensitivity 90 %, specificity 75 %, AUC 0.87) was good.

CONCLUSIONS

Ret-He is a more relevant marker of iron status than ferritin and TSAT. This supports prospectively testing Ret-He to distinguish between iron deficiency and suboptimal erythropoietin dosing as competing causes for anemia. Ferritin is an unhelpful biomarker of iron deficiency in this setting.

Anemia in children following renal transplantation-results from the ESPN/ERA-EDTA Registry

BACKGROUND

Our aim was to determine the prevalence of sub-target hemoglobin (Hb) levels in children with a renal allograft and to identify potential determinants associated with these Hb levels.

METHODS

Data from 3669 children with a functioning renal allograft, aged <18 years between 1 January 2000 and 31 December 2012, from 20 European countries were retrieved from the ESPN/ERA-EDTA Registry, providing 16,170 Hb measurements.

RESULTS

According to the NKF/KDOQI classification and the UK-NICE guidelines, 49.8 and 7.8% of the patients, respectively, were anemic. Hb levels were strongly associated with graft function, with Hb levels of 12.6 g/dl in children with chronic kidney disease (CKD) stage 1, declining to 10.7 g/dl in children with CKD stage 5 (P < 0.001). Higher Hb levels were associated with the use of tacrolimus compared to ciclosporin (0.14 g/dl; 95% confidence interval 0.02-0.27; P = 0.002). Low Hb levels were associated with an increased risk of graft failure (P = 0.01) or combined graft failure and death (P < 0.01), but not with death alone (not significant).

CONCLUSIONS

Anemia is present in a significant proportion of European pediatric kidney transplant recipients and is associated with renal allograft dysfunction and type of immunosuppressants used. In our patient cohort, higher Hb levels were associated with better graft and patient survival and less hypertension.

Safety and usage of darbepoetin alfa in children with chronic kidney disease: prospective registry study

BACKGROUND

Limited prospective data are available on the long-term safety of darbepoetin alfa (DA) for treating anemia in children with chronic kidney disease (CKD).

METHODS

In this prospective, phase IV, observational registry study, children ≤16 years of age with CKD anemia and receiving DA were observed for ≤2 years. Adverse events (AEs), DA dosing, hemoglobin (Hb) concentrations, and transfusions were recorded.

RESULTS

A total of 319 patients were included in the analysis (mean age, 9.1 years), 158 (49.5%) of whom were on dialysis at study entry. Of 434 serious AEs reported in 162 children, the most common were peritonitis (10.0%), gastroenteritis (6.0%), and hypertension (4.1%). Six patients (1.9%) died (unrelated to DA). Four patients (1.3%) experienced six serious adverse drug reactions. The geometric mean DA dose range was 1.4-2.0 μg/kg/month. Mean baseline Hb concentration was 11.1 g/dl; mean values for children receiving and not receiving dialysis at baseline ranged between 10.9 and 11.5 g/dl and 11.2-11.7 g/dl, respectively. Overall, 48 patients (15.0%) received ≥1 transfusion.

CONCLUSIONS

No new safety signals for DA were identified in children receiving DA for CKD anemia for ≤2 years. Based on Hb concentrations and transfusion requirements, DA was effective at managing anemia in these patients.

Advances in Pediatric Intravenous Iron Therapy

Iron deficiency anemia (IDA) continues to be very common worldwide. Intravenous (IV) iron is an infrequently used therapeutic option in children with IDA despite numerous studies in adults and several small but notable pediatric studies showing efficacy and safety. Presently, the availability of newer IV iron products allows for replacement of the total iron deficit at a single setting. These products appear safer compared to the high molecular weight iron dextrans of the past. Herein, we review the medical literature and suggest that front line use of IV iron should be strongly considered in diseases associated with IDA in children.

CRIT-LINE: a noninvasive tool to monitor hemoglobin levels in pediatric hemodialysis patients

BACKGROUND

The national average for achieving the KDOQI-recommended hemoglobin (Hgb) target level of 11-12 g/dL is low with the current anemia management protocol of measuring Hgb levels every 2-4 weeks to guide intervention. The objective of this study was to correlate initial Hgb readings from the CRIT-LINE monitor with actual serum Hgb levels in pediatric patients on hemodialysis (HD).

METHODS

Data were collected from pediatric HD patients who had Hgb tests ordered for routine and/or clinical reasons. Hgb concentrations were read with the CRIT-LINE after 0.5 or 1 L of blood had been processed by HD in patients with a body weight of ≤20 or >20 kg, respectively. Ultrafiltration was kept at a minimum until the CRIT-LINE Hgb was read.

RESULTS

In total, 217 Hgb readings from 23 HD patients were analyzed. Results showed a statistically significant correlation between CRIT-LINE readings and laboratory Hgb measurements (r = 0.94, p < 0.0001) using Pearson correlation coefficients for well-distributed data. The mean Hgb levels measured by CRIT-LINE and the laboratory were 11.12 ± 1.63 and 11.31 ± 1.69 g/dL, respectively.

CONCLUSIONS

The CRIT-LINE monitor is an accurate instrument for monitoring Hgb levels in HD patients. Further studies will be needed to evaluate whether using CRIT-LINE Hgb levels to guide anemia management will improve the percentage of children with Hgb levels within target.

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

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

Prevalence and predictors of the sub-target Hb level in children on dialysis

BACKGROUND

Anaemia is a common and potentially treatable co-morbidity of end-stage renal disease. We aimed to determine the prevalence of the sub-target haemoglobin (Hb) level among European children on dialysis and to identify factors associated with a low Hb level.

METHODS

From the European Society for Paediatric Nephrology (ESPN)/European Renal Association-European Dialysis Transplant Association (ERA-EDTA) registry, data were available on 2351 children between 1 month and 18 years of age, totalling 5546 measurements from 19 countries.

RESULTS

The mean Hb level was 10.8 g/dL (5th-95th percentiles, 7.4-13.9). Among those above 2 years of age, the mean Hb level was 10.9 g/dL (11.4% below 8.5 g/dL), while it was 10.3 g/dL among those below 2 years (11.2% below 8.0 g/dL). A total of 91.2% of the patients were on an erythropoiesis-stimulating agent (ESA). Hb levels increased with age and were higher in peritoneal dialysis compared with haemodialysis patients. Patients with congenital anomalies of the kidney and urinary tract showed the highest Hb levels, and those with cystic kidney diseases or metabolic disorders the lowest ones. Ferritin levels between 25 and 50 ng/mL were associated with the highest Hb levels. We found a weak inverse association between parathyroid hormone (PTH) and Hb. Whereas standardized blood pressure (BP) was not elevated in patients with above-target Hb, elevated systolic BP z-score was noted in those with sub-target Hb levels.

CONCLUSIONS

Sub-target Hb levels remain common in children on dialysis, in spite of virtually all children being treated with ESA; although we cannot exclude under-dosing. Optimal ferritin levels seemed to be slightly lower in children (25-50 ng/mL) than those in adults. Other risk factors for sub-target Hb are dialysis modality and a high PTH level.

Anaemia treatment in chronically dialysed children: a multicentre nationwide observational study

OBJECTIVE

Erythropoiesis-stimulating agents (ESAs) are applied as a standard therapy in children with anaemia in chronic kidney disease. The aim of this study was to describe the efficacy and details of ESA treatment in a population of dialysed children in Poland.

MATERIAL AND METHODS

The study had a prospective observational design and was performed in 12 dialysis centres. The study group comprised 117 dialysed children with a mean age at enrolment of 165.33 (97.18-196.45) months.

RESULTS

Dialysed children were treated mostly with epoietin beta and darbepoietin. The mean dose of ESA was 99 (68-147) U/kg/week with a significant difference between patients on peritoneal dialysis [83 (54-115)] and haemodialysis [134 (103-186)] (p < 0.0001). The mean haemoglobin of all the time-point tests during 6 months was 10.91 ± 1.18 g/dl. The efficacy of anaemia treatment was unsatisfactory in 52% of subjects. In multivariate analysis, initial haemoglobin level <10 g/l, any infection, younger age at first dialysis, malnutrition and inadequate ESA dosage remained significant predictors of anaemia.

CONCLUSIONS

The study revealed that anaemia treatment in Polish children is unsatisfactory. Late commencement of the treatment, inadequate dosing, malnutrition and infections could constitute risk factors for therapy failure.

Cardiovascular disease in children with chronic kidney disease

More than a decade ago, cardiovascular disease (CVD) was recognized as a major cause of death in children with advanced CKD. This observation has sparked the publication of multiple studies assessing cardiovascular risk, mechanisms of disease, and early markers of CVD in this population. Similar to adults, children with CKD have an extremely high prevalence of traditional and uremia-related CVD risk factors. Early markers of cardiomyopathy, such as left ventricular hypertrophy and dysfunction, and early markers of atherosclerosis, such as increased carotid artery intima-media thickness, carotid arterial wall stiffness, and coronary artery calcification, are frequently present in these children, especially those on maintenance dialysis. As a population without preexisting symptomatic cardiac disease, children with CKD potentially receive significant benefit from aggressive attempts to prevent and treat CVD. Early CKD, before needing dialysis, is the optimal time to both identify modifiable risk factors and intervene in an effort to avert future CVD. Slowing the progression of CKD, avoiding long-term dialysis and, if possible, conducting preemptive transplantation may represent the best strategies to decrease the risk of premature cardiac disease and death in children with CKD.

No difference in meeting hemoglobin and albumin targets for dialyzed children with urologic disorders

Urologic disorders are the most common cause of chronic kidney disease in children. To determine whether children with urologic etiology of end-stage renal disease (ESRD) fare better than children with ESRD from other causes while on dialysis, we conducted a cross-sectional study of children <18 years receiving peritoneal and hemodialysis in the United States using data from the Centers for Medicare & Medicaid Services 2005 ESRD CPM Project. We compared baseline demographics and the study groups. In multivariate logistic regression analysis of 1,286 subjects, we assessed whether children with urologic disorders had a higher odds of meeting adult KDOQI targets for hemoglobin levels ≥11 g/dl and albumin ≥3.5 BCG/3.2 BCP g/dl. We conducted a subset analysis of 1,136 patients to examine the impact of erythropoietin on hemoglobin targets. Our results did not reveal differences in achievement of adult hemoglobin targets (adjusted OR: 1.27; p value 0.09; CI: 0.97-1.66) or in the subset analysis with erythropoietin (adjusted OR: 1.32; p value 0.06; CI: 0.98-1.78) or albumin targets (adjusted OR: 1.22; p value 0.21; CI: 0.90-1.65) in adjusted analyses. Due to our study's limitations, it is difficult to determine whether this may result from treatment prior to dialysis initiation or treatment effect of dialysis rather than underlying diagnosis.

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.

Erythropoietin dosing in children with chronic kidney disease: based on body size or on hemoglobin deficit?

There are no investigations demonstrating that body size-adapted doses of erythropoietin (EPO) are as equally effective in children as in adults. A treatment starting with 150 IU/kg body weight per week leads to an insufficient rise in hemoglobin levels in anemic children with chronic kidney disease (CKD). Nevertheless, this strategy is widely used and seems to be the reason for a high percentage of young anemic children in spite of EPO treatment. In children and in adults, 1,000 IU EPO intravenously increases the hemoglobin level equally by 0.04 g/l. This strongly argues for specifying the EPO dose in the treatment of children with CKD in absolute amounts. A prediction model exists which allows the determination of the EPO dose which is expected to raise hemoglobin from a given pretreatment level to a desired steady state level.

Analyses of age, gender and other risk factors of erythropoietin resistance in pediatric and adult dialysis cohorts

Previous studies often report lower responses to erythropoietin (EPO) therapy in pediatric patients on chronic dialysis than those of adults. Because of the greater capacity for hematopoiesis in the younger population, these studies may be confounded by poorly identified variables. Thus, we made parallel studies of pediatric and adult cohorts to explore the relationship between age, gender and other risk factors with EPO resistance. Thirty pediatric subjects (aged 8-20 years) and 66 adult subjects (aged 22-85 years) on chronic hemodialysis and EPO were enrolled. After stratification by 50th percentile of EPO response, the best predictive model was identified by backward elimination of the risk factors with the least contribution to the regression. Relationship between age, gender and EPO resistance was examined by analysis of covariance (ANCOVA). The most predictive model of EPO response for the pediatric cohort had, as the major variables, urea clearance x dialysis duration/total body water (Kt/V), urea reduction ratio (URR), intact parathyroid hormone (iPTH), blood loss, normalized protein catabolic rates (nPCR) and indices of malnutrition and inflammation, whereas adults had iron and folate deficiencies as the dominant variables. Although EPO resistance was more common in female subjects than in male subjects, relationship with neither age nor gender was significant. Furthermore, the prescription of a larger (initiating) EPO dose by pediatric physicians compared with adult nephrologists confounded the interaction between age and EPO resistance. In summary EPO resistance in the pediatric dialysis cohort was predicted by nutritional deficits, inflammation, poor dialysis, and hyperparathyroidism, while iron and folate deficits were the major determinants in adults. Although confounded by the pattern of EPO prescription, neither age nor gender was predictive of EPO resistance in the two study groups.

Hematopoietic growth factor mimetics: from concept to clinic

Hematopoietic growth factor (HGF) mimetics offer a number of attractive advantages as therapeutic agents. Small chemical compounds, in particular, provide reduced cost and oral availability. As many of these mimetics are unrelated in structure to the normal cytokine the immunogenic response is not a significant issue. Isolation of small peptide agonists for erythropoietin (EPO) and thrombopoietin (TPO) receptors has been associated with significant translational challenges and here we summarize approaches used to achieve the potency and stability required for clinical utility. We also compare and contrast the initial screening approaches, and the translational and clinical issues associated with two recently approved TPO mimetics, romiplostim and the orally available eltrombopag. Finally we summarize the development and clinical findings for the EPO mimetic, Hematide, consider alternative approaches, and discuss the future potential for isolation of growth factor (GF) mimetics.

Disparate outcomes in pediatric peritoneal dialysis patients by gender/race in the End-Stage Renal Disease Clinical Performance Measures project

Associations between achievement of adult Kidney Disease Outcomes Quality Initiative (KDOQI) targets for hemoglobin, adequacy and albumin, and race and gender were determined for pediatric peritoneal dialysis patients from the End-Stage Renal Disease (ESRD) Clinical Performance Measures (CPM) project for the period October 2004-March 2005. Fifty-six percent (427/761) of patients were male. Sixty-six percent (500/761) of patients were White. There were no differences in achievement of targets for adults by gender, and no differences in adequacy parameters by race. Blacks had lower mean hemoglobin levels than did Whites (11.1 +/- 1.6 g/dl vs 11.8 +/- 1.4 g/dl, P < 0.0001). Blacks were more likely to have mean hemoglobin levels < 10 g/dl (24% vs 11%, P < 0.0001) and less likely to achieve mean hemoglobin > 11 g/dl (56% vs 72%, P < 0.0001). Whites were more likely to achieve mean serum albumin levels > 4.0/3.7 g/dl [bromocresol green/bromocresol purple (BCG/BCP)] than Blacks were (35% vs 26%, P = 0.0376). In multivariate logistic regression models, White race was associated with mean hemoglobin levels > 11 g/dl [adjusted odds ratio (adj OR) 2.7, 95% confidence interval (CI) 1.7, 4.3] and mean serum albumin > 4.0/3.7 g/dl (BCG/BCP) (adj OR 1.9, 95% CI 1.3, 2.9]. Further study is needed of factors associated with anemia on peritoneal dialysis and barriers to its correction.

Anemia in children with chronic kidney disease

Anemia is a common feature of chronic kidney disease, but the management of anemia in children is complex. Erythropoietin and supplemental iron are used to maintain hemoglobin levels. The National Kidney Foundation-Kidney Disease Outcomes Quality Initiative (NKF-KDOQI) clinical practice guidelines for the management of anemia specifically in children were recently published. Pediatric nephrologists are encouraged to use current clinical practice guidelines and best evidence in conjunction with their clinical experience to optimally manage patients with anemia.

Cardiovascular complications of pediatric chronic kidney disease

Cardiovascular disease (CVD) mortality is a leading cause of death in adult chronic kidney disease (CKD), with exceptionally high rates in young adults, according to the Task Force on Cardiovascular Disease. Recent data indicate that cardiovascular complications are already present in children with CKD. This review summarizes the current literature on cardiac risk factors, mortality and morbidity in children with CKD.

Single-dosage pharmacokinetics of sodium ferric gluconate complex in iron-deficient pediatric hemodialysis patients

BACKGROUND AND OBJECTIVES

The clinical use of sodium ferric gluconate complex in iron-deficient pediatric patients receiving hemodialysis was recently approved. This study was designed to describe the pharmacokinetic parameters of the medication.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Iron-deficient pediatric (< or = 15 yr) hemodialysis patients were randomly assigned to two doses (1.5 and 3.0 mg/kg) of sodium ferric gluconate complex. Blood samples taken during a 1-h infusion and at multiple intervals during 48 h were analyzed for total iron, transferrin-bound iron, and sodium ferric gluconate complex-bound iron.

RESULTS

Forty-nine patients (mean age 12.3 +/- 2.5 yr) participated in the study. Mean serum iron concentrations rapidly increased in a dosage-dependent manner. A rapid rise in total serum iron was followed by a slower, less prominent rise in transferrin-bound iron. This was qualitatively confirmed by visualization of the transferrin bands from polyacrylamide gel electrophoresis. Single-dose pharmacokinetics of sodium ferric gluconate complex-bound iron was described using noncompartmental analytical methods. Mean values for the 1.5 mg/Kg dose were as follows: t(1/2) 2.0 +/- 0.7 h, Cmax 1287 mcg/dl, Tmax 1.1 +/- 0.23 h, Cl 0.69 +/- 0.50 L/h, Vd 1.6 +/- 0.6 L, AUC(0-infinity). 9499 +/- 4089 mcg x hr/dl.

CONCLUSIONS

The infusion of sodium ferric gluconate complex to pediatric patients who receive hemodialysis appears to result in a delayed transfer of iron to transferrin, likely after an initial movement through the reticuloendothelial system. Differences noted between the pediatric and adult pharmacokinetic data may result from the unique aspects of the study populations and the respective study designs.

Iron therapy for renal anemia: how much needed, how much harmful?

Iron deficiency is the most common cause of hyporesponsiveness to erythropoiesis-stimulating agents (ESAs) in end-stage renal disease (ESRD) patients. Iron deficiency can easily be corrected by intravenous iron administration, which is more effective than oral iron supplementation, at least in adult patients with chronic kidney disease (CKD). Iron status can be monitored by different parameters such as ferritin, transferrin saturation, percentage of hypochromic red blood cells, and/or the reticulocyte hemoglobin content, but an increased erythropoietic response to iron supplementation is the most widely accepted reference standard of iron-deficient erythropoiesis. Parenteral iron therapy is not without acute and chronic adverse events. While provocative animal and in vitro studies suggest induction of inflammation, oxidative stress, and kidney damage by available parenteral iron preparations, several recent clinical studies showed the opposite effects as long as intravenous iron was adequately dosed. Thus, within the recommended international guidelines, parenteral iron administration is safe. Intravenous iron therapy should be withheld during acute infection but not during inflammation. The integration of ESA and intravenous iron therapy into anemia management allowed attainment of target hemoglobin values in the majority of pediatric and adult CKD and ESRD patients.

Darbepoetin, effective treatment of anaemia in paediatric patients with chronic renal failure

Darbepoetin alpha (DA) is a unique long-acting treatment for anaemia in patients with chronic renal failure (CRF). This study assessed the mean dose of DA to achieve and maintain haemoglobin (Hb) levels between 11 g/dl and 13 g/dl in CRF children aged 11 years to 18 years. This observational, prospective study was conducted in 39 patients treated with DA. Twenty-nine patients were switched from recombinant human erythropoietin (r-HuEPO), and ten patients were naive to r-HuEPO. Naive patients received initial doses of 0.45 microg/kg of DA. Switched patients received a dose adjusted to the prior dose of r-HuEPO (200 IU r-HuEPO:1 microg DA). Among the switched patients, 79.3% received dialysis. No naive patients underwent dialysis. Overall, 74% of patients showed increased Hb level, with a mean value of 11.6 +/- 1.6 g/dl, using a mean DA dose of 0.63 +/- 0.48 microg/kg per week, and 66.7% patients reached the target Hb level. Hb increased in naive patients from 9.5 (95% CI: 7.7, 11.4) to 11.7 (95% CI: 10.9, 12.6) g/dl and in switched patients from 11.1 (95% CI: 10.6, 11.5) to 11.5 (95% CI: 10.8, 12.2) g/dl). Higher doses of DA were needed in the "switched" than in the "naive" patients to maintain Hb levels over 11 g/dl, respectively 0.73 (95% CI: 0.54, 0.92) and 0.34 (95% CI: 0.16, 0.52) microg/kg per week. Our results indicate the doses of DA necessary to treat CRF patients aged 11 years to 18 years. DA was an effective treatment to stabilise CRF patients at extended dosing intervals.

Erythropoietin: an update on the therapeutic use in newborn infants and children

Recombinant human erythropoietin (epoetin) has become the most widely used cytokine in the world. Following the success of its use in patients with end-stage renal disease, the usefulness of epoetin in other anaemias was assessed, including paediatric patients, mainly newborns. The treatment or prevention of anaemia of prematurity with epoetin resulted in a significant reduction in the number of transfusions and donor exposure. A clear definition of which premature babies must receive therapy is yet to be established. Other indications in neonatal period include hyporegenerative and haemolytic anaemias. The potential for use of the nonhaematopoietic effects of epoetin in newborn infants is a novel and exciting issue. The role of epoetin as a tissue-protective factor for the CNS and intestinal mucosa is under exhaustive investigation. With the exception of chronic renal failure, in older children the efficacy of epoetin has not been evaluated as in adults. Although an impressive amount of studies were carried out during recent years in adult patients with cancer-related or HIV-infection-related anaemias, thus allowing clear conclusions to be established on its efficacy, only a few trials with a small number of patients have been reported in children. Up-to-date, results in paediatric patients suggest that epoetin therapy is as useful as in adult patients, but prospective, randomised trials including large number of patients are essential to achieve definitive conclusions.

Anemia in children with chronic kidney disease

Anemia in children with chronic kidney disease (CKD) is common secondary to inadequate erythropoietin production, iron deficiency, blood loss, inflammation, secondary hyperparathyroidism, uremic toxins, and nutritional deficiencies. Anemia has a variety of deleterious consequences, including associations with increased mortality and left ventricular hypertrophy. Recombinant human erythropoietin is effective in treating anemia in children with CKD, and recent studies show that darbepoetin alpha is an attractive alternative because it requires less frequent injections. Iron deficiency is a major cause of anemia that is resistant to erythropoietin or darbepoetin alpha. Although oral iron is effective in some patients, many children, especially those receiving hemodialysis, require intravenous iron to replenish their iron stores. Both acute dosing and chronic dosing of intravenous iron are effective in pediatric patients.

Cardiovascular disease in children with chronic kidney disease

In children with end-stage renal disease (ESRD), cardiovascular disease (CVD) mortality has not changed for the past 3 decades. Cardiac disease remains the second most common cause of death. Recent data demonstrate a high incidence and prevalence of traditional and chronic kidney disease (CKD)-related CVD risk factors in children. Early markers of cardiomyopathy, such as left ventricular hypertrophy (LVH) and left ventricular dysfunction (LV dysfunction), and early markers of atherosclerosis, such as increased carotid artery intima-media thickness (IMT) and carotid arterial wall stiffness, are frequently found in this patient population. Early identification of modifiable risk factors and treatment of asymptomatic CVD might lead to decrease of cardiovascular morbidity and mortality in young adults who developed CKD during childhood.

Sodium ferric gluconate complex therapy in anemic children on hemodialysis

Pediatric patients with end-stage renal disease undergoing hemodialysis (HD) frequently develop anemia. Administration of recombinant human erythropoietin (rHuEPO) is effective in managing this anemia, although the additional demand for iron often results in iron deficiency. In adult patients undergoing HD, intravenous (IV) iron administration is known to replenish iron stores more effectively than oral iron administration. Nevertheless, IV iron supplementation is underutilized in pediatric patients, possibly because of unproved safety in this population. This international, multicenter study investigated the safety and efficacy of two dosing regimens (1.5 mg kg(-1) and 3.0 mg kg(-1)) of sodium ferric gluconate complex (SFGC) therapy, during eight consecutive HD sessions, in iron-deficient pediatric HD patients receiving concomitant rHuEPO therapy. Safety was evaluated in 66 patients and efficacy was evaluated in 56 patients. Significant increases from baseline were observed in both treatment groups 2 and 4 weeks after cessation of SFGC dosing for mean hemoglobin, hematocrit, transferrin saturation, serum ferritin, and reticulocyte hemoglobin content. Efficacy and safety profiles were comparable for 1.5 mg kg(-1) and 3.0 mg kg(-1) SFGC with no unexpected adverse events with either dose. Administration of SFGC was safe and efficacious in the pediatric HD population. Given the equivalent efficacy of the two doses, an initial dosing regimen of 1.5 mg kg(-1) is recommended for pediatric HD patients.

The spectrum of cardiovascular disease in children with predialysis chronic kidney disease

Cardiovascular disease is the major cause of mortality in adults and children on chronic dialysis and in adults after kidney transplantation. Cardiovascular disease burden and cardiovascular mortality are high in adults with chronic kidney disease. The early development of cardiovascular disease risk factors, some of which are modifiable, largely explain this phenomenon. Limited data are available on the prevalence of chronic kidney disease in children, the prevalence of cardiovascular disease in children with chronic kidney disease, and the prevalence of cardiovascular disease risk factors in these patients. This article summarizes the current knowledge of the prevalence of cardiovascular disease and of cardiovascular disease risk factors in pediatric patients with predialysis chronic kidney disease. Long-term prospective studies are needed to determine the impact of early identification and treatment of cardiovascular disease and its risk factors on the natural history of cardiovascular disease in children with chronic kidney disease.