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

Compassionate use of roxadustat for treatment of refractory renal anemia in an infant

BACKGROUND

Erythropoiesis-stimulating agents (ESAs) have played an important role in the treatment of renal anemia in children, but cannot improve hemoglobin to target level in some cases. Roxadustat, a hypoxia-inducible factor prolyl hydroxylase inhibitor, can stimulate endogenous erythropoietin production and regulate iron metabolism even in patients with kidney failure. However, roxadustat has not yet been approved for use in children.

CASE-DIAGNOSIS/TREATMENT

We report a case of refractory renal anemia in an 80-day-old boy, who was hyporesponsive to ESAs even in combination with iron supplementation and transfusion. Compassionate use of roxadustat successfully corrected the intractable anemia. Hyperkalemia is a manageable adverse event of concern during follow-up.

CONCLUSION

The successful experience in this case may inform the clinical utility of roxadustat for refractory renal anemia in children, which should be further confirmed by well-designed prospective clinical trials.

Diagnosis and management of mineral and bone disorders in infants with CKD: clinical practice points from the ESPN CKD-MBD and Dialysis working groups and the Pediatric Renal Nutrition Taskforce

BACKGROUND

Infants with chronic kidney disease (CKD) form a vulnerable population who are highly prone to mineral and bone disorders (MBD) including biochemical abnormalities, growth retardation, bone deformities, and fractures. We present a position paper on the diagnosis and management of CKD-MBD in infants based on available evidence and the opinion of experts from the European Society for Paediatric Nephrology (ESPN) CKD-MBD and Dialysis working groups and the Pediatric Renal Nutrition Taskforce.

METHODS

PICO (Patient, Intervention, Comparator, Outcomes) questions were generated, and relevant literature searches performed covering a population of infants below 2 years of age with CKD stages 2-5 or on dialysis. Clinical practice points (CPPs) were developed and leveled using the American Academy of Pediatrics grading matrix. A Delphi consensus approach was followed.

RESULTS

We present 34 CPPs for diagnosis and management of CKD-MBD in infants, including dietary control of calcium and phosphate, and medications to prevent and treat CKD-MBD (native and active vitamin D, calcium supplementation, phosphate binders).

CONCLUSION

As there are few high-quality studies in this field, the strength of most statements is weak to moderate, and may need to be adapted to individual patient needs by the treating physician. Research recommendations to study key outcome measures in this unique population are suggested. A higher resolution version of the Graphical abstract is available as Supplementary information.

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.

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.

Lessons learned from the ESPN/ERA-EDTA Registry

End-stage renal disease (ESRD) in children is a medically challenging condition. Due to its rarity and special features, methodologically sound collaborative studies are required. In 2007, a new European registry of pediatric renal replacement therapy (RRT), the ESPN/ERA-EDTA Registry, was launched. In recent years, the Registry has provided comprehensive data on incidence, prevalence, patient characteristics, RRT modalities, and mortality in pediatric ESRD, along with relevant insights into cardiovascular risk, anemia, nutrition and growth, transplantation outcomes, and rare diseases. In this review, we describe the study design and structure underlying the ESPN/ERA-EDTA Registry, summarize the major research findings from more than 20 publications, and discuss current limitations and the future challenges to overcome.

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.

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.

Hemoglobin level and risk of hospitalization and mortality in children on peritoneal dialysis

BACKGROUND

Clinical practice guidelines for management of anemia in children with end-stage kidney disease (ESKD) remain largely opinion-based. In this study, we evaluated the risk of mortality and hospitalization by hemoglobin (Hb) level in a large prevalent population of U.S. children on peritoneal dialysis (PD).

METHODS

Hemoglobin levels in prevalent PD patients from the 2005 End Stage Renal Disease Clinical Performance Measures Project were linked with 5-year mortality and 4-year hospitalization records from the United States Renal Data System.

RESULTS

Of the 468 patients included in the study, the mean age was 11 years, 55 % were male, 67 % were white, 254 (54 %) were hospitalized, and 23 (5 %) died. Median (interquartile range) Hb levels were 11.7 (10.7-12.6) g/dl, and 30 % had Hb levels of <11 g/dl. In adjusted survival analysis, Hb thresholds of 10, 11, or 12 g/dl were not associated with a significant difference in risk of death. The incidence rate ratio (IRR) of hospitalization for patients with a mean Hb of ≥11 g/dl was 0.56 (95 % CI 0.43-0.73). Compared to a reference range of Hb of 11 to <12, Hb of ≥12 g/dl was not associated with a significant difference in hospitalization risk (IRR 0.88; 95 % CI 0.61-1.25). Using age- and sex specific cut-offs for anemia, children who were not anemic had a 27 % decreased risk of hospitalization compared to those with anemia (IRR 0.73; 95 % CI 0.55-0.97). Compared to the first erythropoiesis stimulating agent (ESA) dosing quartile, higher ESA doses were associated with an increased risk of both hospitalization and mortality.

CONCLUSIONS

U.S. children on PD with Hb levels of ≥11 g/dl were less likely to be hospitalized but had no observed difference in mortality. Children who were not anemic were also less likely to be hospitalized. Further study is necessary to elucidate whether a single optimal Hb level or a range applies to the pediatric ESKD population.

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.

Searching the optimal PTH target range in children undergoing peritoneal dialysis: new insights from international cohort studies

The treatment of the mineral and bone disorder associated with chronic kidney disease (CKD-MBD) remains a major challenge in pediatric patients. The principal aims of therapeutic measures are not only to prevent the debilitating skeletal complications and to achieve normal growth but also to preserve long-term cardiovascular health. Serum parathyroid hormone (PTH) levels are used as a surrogate parameter of bone turnover. Whereas it is generally accepted that serum calcium and phosphate levels should be kept within the range for age, current pediatric consensus guidelines differ markedly with respect to the optimal PTH target range and operate on a limited evidence base. Recently, the International Pediatric Dialysis Network (IPPN) established a global registry collecting detailed clinical and biochemical information, including data relevant to CKD-MBD in children on chronic peritoneal dialysis (PD). This review highlights the current evidence basis regarding the optimal PTH target range in pediatric CKD patients, and re-assesses the current guidelines in view of the outcome data collected by the IPPN registry. Based on a comprehensive evaluation of CKD-MBD outcome measures in this global patient cohort, a PTH target range of 1.7-3 times the upper limit of normal (i.e. 100-200 pg/ml) appears reasonable in children undergoing chronic PD.

Comparison of the Elecsys PTH(1-84) assay with four contemporary second generation intact PTH assays and association with other biomarkers in chronic kidney disease patients

OBJECTIVES

The COBAS Elecsys PTH(1-84) assay is a novel, electro-chemiluminescence immunoassay that exclusively measures full-length parathyroid hormone (PTH). The aim of this study is to compare the automated biointact Elecsys PTH(1-84) assay with four contemporary, iPTH assays in chronic kidney disease (CKD) patients.

DESIGN AND METHODS

We compared the Elecsys PTH(1-84) assay with four iPTH assays (Siemens ADVIA Centaur, Ortho Clinical Diagnostics (OCD) VITROS, Beckman Access2, Abbott ARCHITECT) in the measurement of PTH in 83 local CKD patients. Majority of the patients (44) had CKD but were not on dialysis, 15 were on hemodialysis, 15 were on peritoneal dialysis, and 9 were post-renal transplant. The precision performance and correlation of the assays were determined. PTH(1-84) concentrations were correlated with calcium, phosphate, alkaline phosphatase, hemoglobin, HbA1c and lipid concentrations.

RESULTS

The Elecsys PTH(1-84) assay showed comparable precision and good correlation with the iPTH assays. Although the four different iPTH assays correlated well with each other, there was significant discrepancy among assays. The discrepancy among assays increased with increasing PTH concentrations. The ADVIA Centaur and ARCHITECT assays measured significantly higher PTH concentrations than the VITROS and Access2 assays. PTH(1-84) showed a positive association with phosphate and alkaline phosphatase and an inverse association with HbA1c. There was no significant association with lipid concentrations.

CONCLUSIONS

The third generation Elecsys PTH(1-84) assay had comparable precision performance and correlated well with second generation iPTH assays. However, significant discrepancy was found among the four iPTH assays in measuring iPTH in CKD patients.