Anemia in chronic kidney disease

Resistance to Epoetin-Stimulating Agents in Children Receiving Renal Replacement Therapy

The incidence of anemia increases with the stage of chronic kidney disease (CKD). Erythropoietin (EPO) deficiency is a common cause of anemia in CKD. Erythropoietin-stimulating agents (ESAs) are the mainstay of the treatment. Treatment can be challenging due to erythropoietin resistance (ER), which can be assessed using the erythropoietin resistance index (ERI). Our aim was to investigate the factors contributing to high ERI levels in children receiving renal replacement therapy (RRT). Thirty-three children receiving RRT for at least 3 months were included. The mean ERI value was 15.7 IU/kg/w/g/dL. A significant association was observed between serum phosphorus levels and ERI (P = .016, r = 0.41). The mean parathormone (PTH) level was also higher in the high ERI group (599 ± 351 vs 392 ± 320 pg/mL, P = .088). An association, approaching statistical significance, was found between ERI and hypertension (P = .06, r = 0.32). Our study indicated a potential relationship between hyperphosphatemia, possibly secondary hyperparathyroidism, and ERI in children undergoing RRT.

Assessment and management of magnesium and trace element status in children with CKD stages 2-5, on dialysis and post-transplantation: Clinical practice points from the Pediatric Renal Nutrition Taskforce

Children and young people with chronic kidney disease (CKD) are at risk for deficiency or excess of magnesium and trace elements. Kidney function, dialysis, medication, and dietary and supplemental intake can affect their biochemical status. There is much uncertainty about the requirements of magnesium and trace elements in CKD, which leads to variation in practice. The Pediatric Renal Nutrition Taskforce is an international team of pediatric kidney dietitians and pediatric nephrologists, formed to develop evidence-based clinical practice points to improve the nutritional care of children with CKD. PICO (patient, intervention, comparator, and outcomes) questions led the literature searches, which were conducted to ascertain current biochemical status, dietary intake, and factors leading to requirements differing from healthy peers, and to guide nutritional care of children with CKD stages 2-5, on dialysis, and post-transplantation. We address the assessment and intervention of magnesium and the trace elements chromium, copper, fluoride, iodine, manganese, selenium, and zinc. We suggest routine biochemical assessment of magnesium. Trace element assessment is based on clinical suspicion of deficiency or excess and their risk factors, including accumulation, losses, medications, nutrient interactions, and comorbidities. In particular, we suggest assessing magnesium, copper, iodine, and zinc when growth is poor, and evaluating magnesium, copper, selenium, and zinc in the presence of proteinuria. A structured approach to magnesium and trace element management, including biochemical, physical, and dietary assessment, is beneficial in the paucity of evidence. Research recommendations are suggested.

Comparative efficacy of epoetin alfa vs. darbepoetin in children with chronic kidney disease: a systematic review, meta-analysis and cost-effectiveness analysis

BACKGROUND

Recombinant human erythropoietin (rHuEPO) and darbepoetin alfa (DA) are key treatments for anemia in individuals with chronic kidney disease (CKD), including children, but evidence comparing their efficacy in the pediatric population remains inconclusive.

METHODS

This systematic review, adhering to PRISMA guidelines, analyzed randomized controlled trials and observational studies comparing rHuEPO and DA in pediatric patients with CKD (≤ 18 years; ≥ 10 children per study), searched across medical databases and clinical trial registries until 31/12/2024. The Cochrane Risk of Bias was used for assessment. Meta-analysis evaluated hemoglobin (Hb) increase and cost-effectiveness using the incremental cost-effectiveness ratio.

RESULTS

From 1298 screened articles, 7 studies were included: 3 prospective studies, 2 randomized open-label non-inferiority trials, and 2 retrospective cohort studies, comprising 208 children for direct comparisons and 357 for transitioning studies. Meta-analysis found no significant Hb improvement differences between rHuEPO and DA after 21-28 weeks of treatment (DA + 0.15 g/dL, 95% CI - 0.22 to + 0.52). rHuEPO was more cost-effective than DA. Transitioning to DA increased Hb by + 0.93 g/dL (95% CI 0.53-1.33) in children with suboptimal levels, after 21-28 weeks of rHuEPO. The incremental cost-effectiveness ratio of switching to DA was ~ €340 per g/dL of Hb over 24 weeks.

CONCLUSIONS

rHuEPO is the most cost-effective initial anemia treatment in pediatric CKD. However, transitioning to DA may be considered for patients who do not achieve adequate Hb response. The small number of randomized controlled trials (RCTs), variability in dose conversion, and study heterogeneity may limit generalizability.

PROSPERO ID

CRD42023460872.

Association of chronic kidney disease and cardiovascular disease risk with all-cause mortality: an interaction, joint and mediation analysis in Chinese adults

BACKGROUND

Chronic kidney disease (CKD) is a global public health problem. This study aimed to evaluate the complex relationship of CKD and cardiovascular disease (CVD) risk with mortality in different age groups and the mediation effect of CVD risk among Chinese adults.

METHODS

A total of 7533 participants from the 2009 wave of China Health and Nutrition Survey (CHNS) cohort were included in this study and followed up to 2015. CKD was defined as the estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73m2. Framingham risk score (FRS) was used to assess CVD risk. The interaction, joint association of CVD risk and CKD on mortality, and subsequent mediation effect were evaluated using multivariable Cox regression.

RESULTS

CHNS cohort recorded 266 deaths over a mean follow-up time of 5.04 years. The all-mortality rates among adults with CKD and high CVD risk were significantly higher than healthy controls (22.48 and 21.30 per 1000 person-years). After adjusting for covariates of age, gender, BMI, hypertension, diabetes, hyperuricemia, smoking status, and alcohol consumption, the adjusted hazard ratios (aHR) of CKD and high CVD risk were 1.70 (95% CI 1.27-2.28) and 1.62 (95%CI 1.26-2.09), respectively. Joint effect analysis revealed that mortality hazard was highest in CKD patients with high CVD risk (aHR = 3.15, 95% CI 1.92-5.16). Mediation analysis showed that significant partial mediation by SBP and fasting glucose, accounting for 19.2% (p < 0.001) and 3.52% (p = 0.012) of the total effect of CKD on mortality.

CONCLUSIONS

Comprehensive strategies including lifestyle modifications, diet restrictions, and cardio-nephrology multidisciplinary treatment for mitigating CVD risk in CKD patients should focus on middle-aged people and early disease detection.

Anemia Management in Pediatric Chronic Kidney Disease: Current Challenges and Treatment Strategies

A prevalent complication of chronic kidney disease (CKD), iron deficiency anemia (IDA) continues to be underdiagnosed and undertreated. Anemia in CKD in children is associated with a reduced quality of life, and an increased morbidity and mortality. The multifaceted etiology of anemia in CKD involves factors such as diminished endogenous erythropoietin (EPO) production, absolute or functional iron deficiency, and heightened inflammation characterized by elevated hepcidin levels. This paper reviews the complexities of anemia management in pediatric CKD, emphasizing the pivotal role of iron supplementation and erythropoiesis-stimulating agents (ESAs) in ameliorating erythropoiesis and optimizing patient outcomes. While intravenous (IV) iron supplementation effectively addresses iron-restricted erythropoiesis and enhances ESA response, challenges persist in accurately defining anemia in pediatric CKD patients and establishing appropriate treatment targets.

Study on HIF-PHI combined with iron supplement in treatment of renal anemia in rats

BACKGROUND

Roxadustat is a novel hypoxia- inducible factor-prolyl hydroxylase inhibitor(HIF-PHI) used to treat anemia in chronic kidney disease (CKD) patients. It has been reported that roxadustat can slow down kidney damage and delay the development of kidney fibrosis. Anemia and iron deficiency are often associated with the vast majority CKD patients, and insufficient available iron or total iron storage is often the most common cause of anemia and ESAs resistance in CKD patients. The role of iron availability in the pathogenesis of anemia in chronic kidney disease has received increasing attention.

OBJECTIVES

To explore whether combined roxadustat and polysaccharide-iron complex (PIC) is more successful than standalone roxadustat, the appropriate iron supplement dosage and mechanism of roxadustat in the treatment of CKD.

MATERIALS AND METHODS

Healthy male Sprague Dawley rats were randomly divided into two groups: the control (NC) group which were sham-operated and the CKD group. The CKD group was given an adenine diet for three weeks after right unilateral nephrectomy and further divided into 6 groups: the CKD only, CKD + PIC, CKD + Roxa, CKD + PIC (25 mg/kg) + Roxa, CKD + PIC (50 mg/kg) + Roxa, and CKD + PIC (75 mg/kg) + Roxa groups. The sham-operated rats receiving only standard diet served as the control group. Roxadustat were administrated intragastrically at 10 mg/kg thrice per week in groups with Roxa. The hemoglobin (Hb), reticulocyte hemoglobin equivalent (RET-He), reticulocyte % (RET%), plasma urea nitrogen (BUN), plasma creatinine (Cr), serum iron (SI), Total iron binding capacity (TIBC), serum hepcidin-25, interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), interleukin-1β (IL- 1β), and High mobility group protein B1 (HMGB1) levels of each group of rats were assessed. Masson staining was used to evaluate renal fibrosis, and quantitative real-time Polymerase Chain Reaction (RT-PCR) was used to detect the mRNA expression of alpha-smooth muscle actin (α-SMA) and Fibronectin (Fn) in rat renal tissues to further evaluate renal fibrosis.

RESULTS

Level of Hb in the CKD + PIC (75 mg/kg) + Roxa group increased the fastest, roxadustat combined with PIC in the treatment of renal anemia was significantly more effective than Roxadustat or PIC alone. On day 105, in the CKD + PIC (75 mg/kg) + Roxa group, there was a significant decrease in BUN and Cr levels compared to the CKD only group (p < 0.05). Roxadustat reduces the level of hepcidin, IL-6, TNF-α, IL-1β and HMGB1in CKD rats. (p < 0.05). Roxadustat alleviates renal fibrosis in CKD rats (p < 0.05).

CONCLUSIONS

HIF-PHI combined with iron supplement (Roxadustat combined with PIC) has an improved effect on the treatment of renal anemia, and early administration of sufficient iron enables the Hb to rise rapidly. Early administration of adequate dose of PIC is necessary for renal anemia. HIF-PHI can improve iron metabolism, alleviate the microinflammatory state, alleviate renal fibrosis and plays a beneficial role in the treatment of renal fibrosis in CKD rats.

Anemia and its predictors among patients on hemodialysis, at Felege Hiote Referral Hospital, Northwest Ethiopia, 2022: a retrospective cohort study

BACKGROUND

Anemia is a critical complication among hemodialysis patients, often leading to poor outcomes. This study aimed to assess anemia prevalence and identify predictors among hemodialysis patients at Felege Hiote Referral Hospital, Northwest Ethiopia, in 2022.

RESEARCH DESIGN AND METHODS

A retrospective cohort study analyzed 410 hemodialysis patients from January 2018 to February 2022. Data was collected from medical records, entered using Epi-data Version 4.1, and analyzed with STATA Version 14. Kaplan-Meier survival curves assessed survival time, while Cox regression identified anemia predictors.

RESULTS

Of 410 patients, 66 (16.1%) developed anemia, with an incidence rate of 7.9 per 100 person-years (95% CI: 3.1-13.5). Significant predictors included female sex (IRR: 1.5, p = 0.04), rural residence (IRR: 2.5, p = 0.01), low body mass index (IRR: 1.6, p = 0.02), and congestive heart failure (IRR: 6.9, p = 0.02).

CONCLUSIONS

Anemia prevalence among hemodialysis patients is high, with key predictors including gender, residence, body mass index, and comorbidities. Interventions targeting these factors, especially in rural areas, could reduce anemia incidence. Study limitations include single-center data, incomplete variables, and lack of causality.

Do probiotics and iron supplementation have any impact on element distribution in rat kidneys? - bioimaging by laser ablation inductively coupled plasma mass spectrometry

This study investigates the influence of multistrain probiotics and iron supplementation on the distribution and interaction of trace elements in the kidneys of Wistar rats using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) bioimaging. Forty 6-week-old female Wistar rats were divided into five groups, each fed an AIN-93 M diet with varying additions or deficiencies of iron and probiotics, which included a control, an iron-deficient diet, an iron-deficient diet with probiotics, an iron-deficient diet with iron supplementation, and an iron-deficient diet with both probiotics and iron supplementation. The obtained two-dimensional maps of the distribution of elements reveal distinct locations of Cu, Fe, Mn, and Zn in specific tissues of rat kidneys. Specifically, Cu and Fe were co-localized in the renal cortex, while Zn was mostly absent from regions where Cu and Fe accumulated. Fe supplementation alone increased Fe in the renal cortex, while probiotics enhanced this effect, suggesting a synergistic role in Fe absorption. The total content of elements in the kidneys of all groups was determined after digestion: Cu 13.3-24.7 mg kg-1, Fe 218-509 mg kg-1, Mn 0.87-1.29 mg kg-1, and Zn 28.6-40.1 mg kg-1. Competitive interactions among Cu, Fe, and Zn were observed, with probiotics modulating their concentrations and distribution, highlighting their role in trace element homeostasis. Our research provides insights into the interactions between dietary supplements, probiotics, and trace element distribution in kidneys, paving the way for targeted nutritional interventions. This study highlights the need for further research on trace element functions in organisms and their impact on health.

Growth in children with chronic kidney disease and associated risk factors for short stature

INTRODUCTION

Growth failure in chronic kidney disease is related to high morbidity and mortality. Growth retardation in this disease is multifactorial. Knowing the modifiable factors and establishing strategies to improve care for affected children is paramount.

OBJECTIVES

To describe growth patterns in children with chronic kidney disease and the risk factors associated with short stature.

METHODS

We retrospectively analyzed anthropometric and epidemiological data, birth weight, prematurity, and bicarbonate, hemoglobin, calcium, phosphate, alkaline phosphatase, and parathormone levels of children with stages 3-5 CKD not on dialysis, followed for at least one year.

RESULTS

We included 43 children, the majority of which were boys (65%). The mean height/length /age z-score of the children at the beginning and follow-up was -1.89 ± 1.84 and -2.4 ± 1.67, respectively (p = 0.011). Fifty-one percent of the children had short stature, and these children were younger than those with adequate stature (p = 0.027). PTH levels at the beginning of the follow-up correlated with height/length/age z-score. A sub-analysis with children under five (n = 17) showed that 10 (58.8%) of them failed to thrive and had a lower weight/age z-score (0.031) and lower BMI/age z-score (p = 0.047).

CONCLUSION

Children, particularly younger ones, with chronic kidney disease who were not on dialysis had a high prevalence of short stature. PTH levels were correlated with height z-score, and growth failure was associated with worse nutritional status. Therefore, it is essential to monitor the growth of these children, control hyperparathyroidism, and provide nutritional support.

Activation of PERK/eIF2α/ATF4/CHOP branch of endoplasmic reticulum stress response and cooperation between HIF-1α and ATF4 promotes Daprodustat-induced vascular calcification

Introduction: Vascular calcification is accelerated in patients with chronic kidney disease (CKD) and increases the risk of cardiovascular events. CKD is frequently associated with anemia. Daprodustat (DPD) is a prolyl hydroxylase inhibitor for the treatment of CKD-associated anemia that enhances erythropoiesis through the activation of the hypoxia-inducible factor 1 (HIF-1) pathway. Studies showed that DPD promotes osteogenic differentiation of human aortic smooth muscle cells (HAoSMCs) and increases aorta calcification in mice with CKD. HIF-1 activation has been linked with endoplasmic reticulum (ER) stress; therefore, here we investigated the potential contribution of ER stress, particularly activating transcription factor 4 (ATF4), to the pro-calcification effect of DPD. Methods: Here, we used an adenine-induced CKD mouse model and HAoSMCs as an in vitro vascular calcification model to study the effect of DPD. Results: DPD treatment (15 mg/kg/day) corrects anemia but increases the expression of hypoxia (Glut1, VEGFA), ER stress (ATF4, CHOP, and GRP78), and osteo-/chondrogenic (Runx2, Sox9, BMP2, and Msx2) markers and accelerates aorta and kidney calcification in CKD mice. DPD activates the PERK/eIF2α/ATF4/CHOP pathway and promotes high phosphate-induced osteo-/chondrogenic differentiation of HAoSMCs. Inhibition of ER stress with 4-PBA or silencing of ATF4 attenuates HAoSMC calcification. DPD-induced ATF4 expression is abolished in the absence of HIF-1α; however, knockdown of ATF4 does not affect HIF-1α expression. Conclusion: We concluded that DPD induces ER stress in vitro and in vivo, in which ATF4 serves as a downstream effector of HIF-1 activation. Targeting ATF4 could be a potential therapeutic approach to attenuate the pro-calcific effect of DPD.

Management of chronic kidney disease: The current novel and forgotten therapies

Chronic kidney disease (CKD) is a progressive and incurable condition that imposes a significant burden on an aging society. Although the exact prevalence of this disease is unknown, it is estimated to affect at least 800 million people worldwide. Patients with diabetes or hypertension are at a higher risk of developing chronic kidney damage. As the kidneys play a crucial role in vital physiological processes, damage to these organs can disrupt the balance of water and electrolytes, regulation of blood pressure, elimination of toxins, and metabolism of vitamin D. Early diagnosis is paramount to prevent potential complications. Treatment options such as dietary modifications and medications can help slow disease progression. In our narrative review, we have summarized the available therapeutic options to slow the progression of chronic kidney disease. Many new drug treatments have recently become available, offering a beacon of hope and optimism in CKD management. Nonetheless, disease prevention remains the most critical step in disease management. Given the significant impact of CKD on public health, there is a pressing need for further research. With the development of new technologies and advancements in medical knowledge, we hope to find more effective diagnostic tools and treatments for CKD patients.

Anemia of Chronic Kidney Disease-A Narrative Review of Its Pathophysiology, Diagnosis, and Management

Anemia is one of the most common chronic kidney disease (CKD) complications. It negatively affects patients' quality of life and clinical outcomes. The pathophysiology of anemia in CKD involves the interplay of various factors such as erythropoietin (EPO) deficiency, iron dysregulation, chronic inflammation, bone marrow dysfunction, and nutritional deficiencies. Despite recent advances in understanding this condition, anemia still remains a serious clinical challenge in population of patients with CKD. Several guidelines have been published with the aim to systematize the diagnostic approach and treatment of anemia; however, due to emerging data, many recommendations vary between publications. Recent studies indicate a potential of novel biomarkers to evaluate anemia and related conditions such as iron deficiency, which is often present in CKD patients. Our article aims to summarize the pathophysiology of anemia in CKD, as well as the diagnosis and management of this condition, including novel therapeutic approaches such as hypoxia-inducible factor-prolyl hydroxylase inhibitors (HIF-PHI). Understanding these complex subjects is crucial for a targeted approach to diagnose and treat patients with anemia in CKD effectively.

Role of Nutrients in Pediatric Non-Dialysis Chronic Kidney Disease: From Pathogenesis to Correct Supplementation

Nutrition management is fundamental for children with chronic kidney disease (CKD). Fluid balance and low-protein and low-sodium diets are the more stressed fields from a nutritional point of view. At the same time, the role of micronutrients is often underestimated. Starting from the causes that could lead to potential micronutrient deficiencies in these patients, this review considers all micronutrients that could be administered in CKD to improve the prognosis of this disease.

High Ferritin and Low Total Iron-Binding Capacity in Plasma Predict All-Cause Mortality During the First 3 Years of Hemodialysis in Patients with End-Stage Chronic Kidney Disease

Aim

To determine all-cause mortality rate and the predictive value of plasma ferritin and total iron-binding capacity (TIBC) concentrations for mortality during the first 3 years of hemodialysis in patients with end-stage chronic renal disease (ESRD).

Methods

We conducted a study on 174 ESRD patients (estimated Glomerular Filtration Rate < 15 mL/min/1.73m2). The plasma TIBC level was quantified by the ELISA method in all patients at the time before hemodialysis. Based on TIBC concentration, patients were divided equally into 2 groups. Each group had 87 patients. Patients were initiated on hemodialysis, and patients who died from any cause during the first 3 years of hemodialysis were recorded.

Results

The all-cause mortality rate of ESRD patients in the first 3 years of maintenance hemodialysis was 22.9%. Plasma high hs-CRP, high ferritin, and low TIBC concentrations were independent factors associated with all-cause mortality in the patients. Plasma ferritin (cut-off value = 454.2 ng/L) and TIBC (cut-off value = 39.84 µmol/L) were predictors of all-cause mortality, AUC is: 0.772; 0.723, p < 0.001.

Conclusion

Plasma ferritin and TIBC were good predictors of all-cause mortality in ESRD patients during the first 3 years of hemodialysis.

Long-term treatment of chronic kidney disease patients with anemia using hypoxia-inducible factor prolyl hydroxylase inhibitors: potential concerns

Hypoxia-inducible factor prolyl hydroxylase inhibitors (HIF-PHIs) have been approved in several countries as a supplement or even an alternative to the clinical treatment of anemia in patients with chronic kidney disease (CKD). Activation of HIF by HIF-PHIs effectively increases hemoglobin (Hb) level in CKD patients by inducing multiple HIF downstream signaling pathways. This indicates that HIF-PHIs have effects beyond erythropoietin, while their potential benefits and risks should be necessarily assessed. Multiple clinical trials have largely demonstrated the efficacy and safety of HIF-PHIs in the short-term treatment of anemia. However, in terms of long-term administration, especially over 1 year, the benefits and risks of HIF-PHIs still need to be assessed. Particular attention should be paid to the risk of kidney disease progression, cardiovascular events, retinal diseases, and tumor risk. This review aims to summarize the current potential risks and benefits of HIF-PHIs in CKD patients with anemia and further discuss the mechanism of action and pharmacological properties of HIF-PHIs, in order to provide direction and theoretical support for future studies.

Bone Disorders in Pediatric Chronic Kidney Disease: A Literature Review

Intense changes in mineral and bone metabolism are frequent in chronic kidney disease (CKD) and represent an important cause of morbidity and reduced quality of life. These disorders have conventionally been defined as renal osteodystrophy and classified based on bone biopsy, but due to a lack of bone biopsy data and validated radiological methods to evaluate bone morphology in children, it has been challenging to effectively assess renal osteodystrophy in pediatric CKD; the consequence has been the suboptimal management of bone disorders in children. CKD-mineral and bone disorder (CKD-MBD) is a new expression used to describe a systemic disorder of mineral and bone metabolism as a result of CKD. CKD-MBD is a triad of biochemical imbalances in calcium, phosphate, parathyroid hormone, and vitamin D; bone deformities and soft tissue calcification. This literature review aims to explore the pathogenesis, diagnostic approach, and treatment of CKD-MBD in children and the effects of renal osteodystrophy on growing skeleton, with a specific focus on the biological basis of this peculiar condition.

Clinical Experience of a Long-acting Pegylated Erythropoietin-Stimulating Agent in Pediatric Chronic Kidney Disease

OBJECTIVE

Management of anemia of chronic kidney disease (CKD) often includes subcutaneous or intravenous administration of erythropoietin-stimulating agents (ESAs). Mircera, a pegylated continuous erythropoietin receptor agonist, has a longer duration of action and requires less frequent administration than other ESAs. Pediatric experience with Mircera is limited. We retrospectively reviewed our long-term experience of Mircera in a national pediatric nephrology center.

METHODS

Patients were identified via an electronic patient record database. Data collected included demographics (sex, age, etiology of CKD, CKD stage, dialysis modality), dosing information, and laboratory data-hemoglobin (Hb), parathormone (PTH), ferritin, hematinics prior to commencing Mircera and all subsequent values associated with dose adjustments.

RESULTS

Seventy-seven patients aged 2 to 18 years, with CKD stages 2 to 5T had received at least 1 dose of Mircera, with 75 patients having sufficient data and a total of 1473 doses. No patients discontinued Mircera owing to adverse effects. One patient experienced a potential severe adverse drug reaction. Mircera was effective in improving or maintaining Hb ≥10.0 g/dL in most (58/75, 77.3%) patients. The median dose to achieve Hb ≥10.0 g/dL was 2.1 µg/kg/4 wk. Most doses (1039, 71.5%) were administered 4-weekly. The doses (161, 11.1%) that were administered 6-weekly remained efficacious. Thirty-two patients started Mircera with Hb <10.0 g/dL; 26 (81%) achieved Hb ≥10.0 g/dL within a median time of 4 months. Mircera was less effective if given every 8 weeks, or in the presence of hyperparathyroidism or hyperferritinemia.

CONCLUSION

Mircera appears safe and effective in pediatric patients with CKD.

Patient level factors increase risk of acute kidney disease in hospitalized children with acute kidney injury

BACKGROUND

Studies in adults have shown that persistent kidney dysfunction ≥7-90 days following acute kidney injury (AKI), termed acute kidney disease (AKD), increases chronic kidney disease (CKD) and mortality risk. Little is known about the factors associated with the transition of AKI to AKD and the impact of AKD on outcomes in children. The aim of this study is to evaluate risk factors for progression of AKI to AKD in hospitalized children and to determine if AKD is a risk factor for CKD.

METHODS

Retrospective cohort study of children age ≤18 years admitted with AKI to all pediatric units at a single tertiary-care children's hospital between 2015 and 2019. Exclusion criteria included insufficient serum creatinine values to evaluate for AKD, chronic dialysis, or previous kidney transplant.

RESULTS

A total of 528 children with AKI were included in the study. There were 297 (56.3%) hospitalized AKI survivors who developed AKD. Among children with AKD, 45.5% developed CKD compared to 18.7% in the group without AKD (OR 4.0, 95% CI 2.1-7.4, p-value <0.001 using multivariable logistic regression analysis including other covariates). Multivariable logistic regression model identified age at AKI diagnosis, PCICU and NICU admission, prematurity, malignancy, bone marrow transplant, previous AKI, mechanical ventilation, AKI stage, duration of kidney injury, and need for kidney replacement therapy during day 1-7 as risk factors for AKD after AKI.

CONCLUSIONS

AKD is common among hospitalized children with AKI and multiple risk factors are associated with AKD. Children that progress from AKI to AKD are at higher risk of developing CKD. A higher resolution version of the Graphical abstract is available as Supplementary information.

Hemoglobin Levels in Peruvian Patients with Chronic Kidney Disease at Different Altitudes

Hurtado-Aréstegui, Abdías, Karina Rosales-Mendoza, Yanissa Venegas-Justiniano, José Gonzales-Polar, Rina Barreto-Jara, and Alaciel Melissa Palacios-Guillén. Hemoglobin levels in Peruvian patients with chronic kidney disease at different altitudes. High Alt Med Biol. 24:209-213, 2023. Background: Decreased hemoglobin is a manifestation of chronic kidney disease (CKD), and people who reside at high altitude adapt to hypoxia by increasing their hemoglobin. The study's objective was to determine the influence of altitude and the associated factors on the hemoglobin levels of patients with CKD who were not on dialysis (ND). Methods: This exploratory and cross-sectional study was carried out in three Peruvian cities, located at different altitudes: (1) "sea level" (161 m), (2) "moderate altitude" (2,335 m), and "high altitude" (3,399 m). The study included female and male individuals between 20 and 90 years old, with CKD stage 3a, through stage 5. Results: Of the 256 volunteers evaluated, 92 lived at sea level, 82 at moderate altitude, and 82 at high altitude. The three groups were similar in age, number of volunteers in each CKD stage, systolic blood pressure, and diastolic blood pressure. Hemoglobin levels were statistically different according to gender (p = 0.024), CKD stage, and altitude (p < 0.001). High-altitude dwellers had higher hemoglobin by 2.5 g/dl (95% confidence interval: 1.8-3.1, p < 0.001) than those living at lower altitudes (adjusted for gender, age, nutritional status, and smoking habit). For all CKD stages, the high-altitude population had higher hemoglobin levels than population at moderate altitude and at sea level. Conclusion: Subjects living at high altitude with CKD stages 3 to 5 who are yet ND have higher hemoglobin levels than those who live at moderate altitude and at sea level.

Sarcopenia and Anemia in Elderly Koreans: A Nationwide Population-Based Study

Sarcopenia and anemia are common diseases in the elderly and are caused by various factors. In this study, the association between sarcopenia and anemia in an elderly Korean population was examined. The Korea Centers for Disease Control and Prevention's cross-sectional, nationally representative Korea National Health and Nutrition Examination Survey (KNHANES, 2008-2011) served as the source of the data for this study. Of the 2769 participants (1167 men and 1602 women) included in this study, a significant association was found between sarcopenia and anemia in the elderly in Korea. In Model 1, unadjusted for covariates, the prevalence of sarcopenia in all participants was 1.805 (95% CI 1.364-2.388) and 2.746 (95% CI 1.740-4.334) in men, and 1.494 (95% CI 1.045-2.138) in women. In Model 4, adjusted for all covariates, the prevalence of sarcopenia in all participants was 1.455 (95% CI 1.064-1.989) and 2.649 (95% CI 1.475-4.755) in men, but it was insignificant in women. While prior studies failed to consider variables such as exercise status and nutritional intake, this research incorporated these factors as covariates. Despite this comprehensive approach, this study still revealed an independent association between sarcopenia and anemia. Moreover, a significant association was uncovered among elderly men, with no corresponding association identified among women.

The association of hepcidin, reticulocyte hemoglobin equivalent and anemia-related indicators on anemia in chronic kidney disease

Hepcidin is an essential regulator of iron homeostasis in chronic kidney disease (CKD) anemia, reticulocyte hemoglobin equivalent (RET-He) can be used to evaluate the availability of iron for erythropoiesis. Previous research has found that hepcidin indirectly regulates RET-He. This study aimed to investigate the association of hepcidin, RET-He and anemia-related indicators on anemia in chronic kidney disease. A total of 230 individuals were recruited, including 40 CKD3-4 patients, 70 CKD5 patients without renal replacement therapy, 50 peritoneal dialysis patients, and 70 hemodialysis patients. The serum levels of hemoglobin (Hb), reticulocyte, RET-He, serum iron, serum creatinine, serum ferritin, total iron binding capacity, hepcidin-25, high sensitivity C-reactive protein, transferrin, erythropoietin, intrinsic factor antibody, soluble transferrin receptor and interleukins-6 (IL-6) were measured. Hepcidin-25 was positively associated with IL-6, and negatively with total iron binding capacity, intrinsic factor antibody, and transferrin. Reticulocyte Hb equivalent was associated positively with Hb, serum ferritin, serum iron, transferrin saturation, and negatively with serum creatinine, reticulocyte, IL-6, STfR. Hepcidin-25 was not associated with RET-He, while IL-6 was independently associated with hepcidin-25 and RET-He, suggesting that hepcidin has no effffect on the iron dynamics of reticulocytes in CKD, may be related to IL-6, indicate a likelihood of a threshold for stimulation of hepcidin-25 expression by IL-6 in order to indirectly regulates RET-He.

A network meta-analysis of the efficacy of hypoxia-inducible factor prolyl-hydroxylase inhibitors in dialysis chronic kidney disease

BACKGROUND

Five types of HIF-PHIs have been authorized for anemia treatment in CKD patients in China and Japan. These are enarodustat, roxadustat, daprodustat, vadadustat, and molidustat. How effectively they compare to ESAs about clinical results in CKD-DD patients is uncertain. This study examined the RCT evidence about the benefits and risks of HIF-PHIs and ESAs in dialysis CKD patients.

METHODS

We conducted an extensive investigation and network meta-analysis of RCTs. In these RCTs, patients with CKD-DD received one of five different HIF-PHI or ESAs, a placebo, and no medical intervention. Outcomes included hemoglobin, iron parameters, and adverse events, and there were four weeks of follow-up at least. A frequentist framework for multivariate random effects meta-analyzed the results. The effect sizes of categorical variables were displayed as odds ratios. Mean differences were employed for computing continuous outcomes with common units; otherwise, standardized mean differences were applied. The Cochrane tool evaluated the bias risk in RCTs.

RESULTS

26 RCTs with 14945 patients were qualified for inclusion. Compared to the placebo, HIF-PHIs and ESAs dramatically boosted hemoglobin without affecting serum iron. Roxadustat performed better hemoglobin levels than ESAs (MD 0.32, 95% CI 0.10 to 0.53) and daprodustat (0.46, 0.09 to 0.84). Roxadustat (91.8%) was the top hemoglobin treatment among all medical interventions, as determined by the SUCRA ranking. However, roxadustat caused more thrombosis and hypertension than ESAs (1.61, 1.22 to 2.12) and vadadustat (1.36, 1.01 to 1.82). The lowest rates of hypertension and thrombosis were seen in molidustat (80.7%) and ESAs (88.5%). Compared with a placebo, ESAs and HIF-PHIs all affected TSAT levels. Except for molidustat, the other four HIF-PHIs impact different iron parameters. Regarding ferritin reduction, roxadustat (90.9%) and daprodustat (60.9%) came out on top. Enarodustat (80.9%) and roxadustat (74%) placed best and second in lowering hepcidin levels. The former two medicines for TIBC improvement were vadadustat (98.7%) and enarodustat (80.9%).

CONCLUSION

The most effective treatment for hemoglobin correction is roxadustat. The superior efficacy of reducing hepcidin makes roxadustat and enarodustat appropriate for patients with inflammation. However, the increased risk of hypertension and thrombosis associated with roxadustat should be noted. In patients at risk for hypertension and thrombosis, molidustat and ESAs may be preferable options. When administering roxadustat and daprodustat, clinicians should check ferritin to assess iron storage. Lower TSAT in patients receiving HIF-PHIs and ESAs treatment suggests intravenous iron supplements are needed.

Respiratory complications and sleep disorders in children with chronic kidney disease: A correlation often underestimated

Chronic Kidney Disease (CKD) is characterized by a progressive and irreversible loss of kidney function which gradually leads to end-stage kidney disease (ESKD). Virtually all the organs are damaged by the toxicity of uremic compounds. The lungs may be affected and the impaired pulmonary function may be the direct result of fluid retention and metabolic, endocrine and cardiovascular alterations, as well as systemic activation of the inflammation. An increased prevalence in sleep disorders (SD) is also reported in patients with CKD, leading to a further negative impact on overall health and quality of life. While these complex relationships are well documented in the adult population, these aspects remain relatively little investigated in children. The aim of this review is to provide a brief overview of the pathophysiology between lung and kidney and to summarize how CKD may affect respiratory function and sleep in children.

Efficacy of Lanthanum Carbonate and Sevelamer Carbonate as Phosphate Binders in Chronic Kidney Disease-A Comparative Clinical Study

(1) Background: Hyperphosphatemia is correlated with an increased rate of mortality and morbidity due to cardiovascular diseases in chronic kidney disease (CKD) patients. It can be improved by restricting dietary intake of phosphate and oral phosphate binders, such as lanthanum carbonate and sevelamer carbonate. (2) Objective: To evaluate the clinical efficacy of sevelamer carbonate in comparison to lanthanum carbonate as phosphate binders for the treatment of hyperphosphatemia in CKD patients. (3) Methods: A randomized control comparative clinical study was conducted for one year on 150 CKD patients associated with hyperphosphatemia, divided into two groups, i.e., Group 1 (n = 75) treated with sevelamer carbonate 800 mg thrice daily and Group 2 (n = 75) treated with lanthanum carbonate 500 mg thrice daily. The patients were assessed at the time of enrollment in the study, after three months and after six months from baseline for different parameters, i.e., complete blood count, liver function tests, renal function tests, electrolytes, and serum phosphate level. (4) Results: 150 CKD patients aged 51-60 participated in the study. The mean age of patients was 54 ± 4.6 years, and males (55.71%) were more common than females (44.29%). Hypertension was the common comorbidity in both groups with chronic kidney disease. After six months of treatment, the mean serum phosphate level was significantly decreased from 8.31 ± 0.09 mg/dL to 5.11 ± 0.18 (38%) in Group 1 and from 8.79 ± 0.28 mg/dl to 4.02 ± 0.12 (54%; p < 0.05) in Group 2, respectively. In both groups, no significant difference was found in other parameters such as parathyroid hormone, calcium, uric acid, LFT, RFT, CBC, etc. (5) Conclusion: Lanthanum carbonate is more efficacious in lowering serum phosphate concentrations and effectively managing hyperphosphatemia as compared to sevelamer carbonate.

Urine alpha 1-microglobulin-to-creatinine ratio and beta 2-microglobulin-to-creatinine ratio for detecting CAKUT with kidney dysfunction in children

BACKGROUND

The leading cause of advanced chronic kidney disease (CKD) in children is congenital anomalies of the kidney and urinary tract (CAKUT). However, the most appropriate parameters of biochemical urine analysis for detecting CAKUT with kidney dysfunction are not known.

METHODS

The present observational study analyzed data on children with CAKUT (stage 2-4 CKD) and the general pediatric population obtained from school urine screenings. The sensitivity and specificity of urine alpha 1-microglobulin-, beta 2-microglobulin-, protein-, and the albumin-to-creatinine ratios (AMCR, BMCR, PCR, ACR, respectively) in detecting CAKUT with kidney dysfunction were compared with those of the conventional urine dipstick, and the most appropriate of these four parameters were evaluated.

RESULTS

In total, 77 children with CAKUT and 1712 subjects in the general pediatric population fulfilled the eligibility criteria. Conventional dipstick urinalysis was insufficient due to its low sensitivity; even when the threshold of proteinuria was +/-, its sensitivity was only 29.7% for stage 2 and 44.1% for stage 3 CKD. Among the four parameters assessed, the AMCR and BMCR were adequate for detecting CAKUT in children with stage 3-4 CKD (the respective sensitivity and specificity of the AMCR for detecting CAKUT in stage 3 CKD was 79.4% and 97.5% while that of BMCR was 82.4% and 97.5%). These data were validated using national cohort data.

CONCLUSION

AMCR and BMCR are superior to dipstick urinalysis, PCR, and ACR in detecting CAKUT with kidney dysfunction, particularly stage 3 CKD. However, for AMCR, external validation is required. A higher resolution version of the Graphical abstract is available as Supplementary information.

A nomogram for predicting the 4-year risk of chronic kidney disease among Chinese elderly adults

BACKGROUND

Chronic kidney disease (CKD) has become a major public health problem across the globe, leading to various complications. This study aimed to construct a nomogram to predict the 4-year risk of CKD among Chinese adults.

METHODS

The study was based on the China Health and Retirement Longitudinal Study (CHARLS). A total of 3562 participants with complete information in CHARLS2011 and CHARLS2015 were included, and further divided into the training cohort and the validation cohort by a ratio of 7:3. Univariate and multivariate logistic regression analyses were used to select variables of the nomogram. The nomogram was evaluated by receiver-operating characteristic curve, calibration plots, and decision curve analysis (DCA).

RESULTS

In all, 2494 and 1068 participants were included in the training cohort and the validation cohort, respectively. A total of 413 participants developed CKD in the following 4 years. Five variables selected by multivariate logistic regression were incorporated in the nomogram, consisting of gender, hypertension, the estimated glomerular filtration rate (eGFR), hemoglobin, and Cystatin C. The area under curve was 0.809 and 0.837 in the training cohort and the validation cohort, respectively. The calibration plots showed agreement between the nomogram-predicted probability and the observed probability. DCA indicated that the nomogram had potential clinical use.

CONCLUSIONS

A predictive nomogram was established and internally validated in aid of identifying individuals at increased risk of CKD.

Mean corpuscular haemoglobin concentration and outcomes in heart failure with preserved ejection fraction

AIMS

This study aims to evaluate the prognostic value of mean corpuscular haemoglobin concentration (MCHC) on clinical outcomes in patients with heart failure with preserved ejection fraction (HFpEF).

METHODS AND RESULTS

We analysed HFpEF participants from the Americas in the Treatment of Preserved Cardiac Function Heart Failure with an Aldosterone Antagonist (TOPCAT) trial with available baseline data (n = 1747). Patients were grouped into hypochromia or non-hypochromia group according to a MCHC cut-off level of 330 g/L. Cox proportional hazard model was used to explore the prognostic value of hypochromia on the long-term clinical outcomes (the primary endpoint [composite of cardiovascular mortality, HF hospitalization and aborted cardiac arrest], any-cause and HF hospitalization, all-cause and cardiovascular mortality). Patients were further stratified according to baseline estimated glomerular filtration rate (eGFR) to explore the impact of renal dysfunction on the prognostic value of hypochromia. Baseline hypochromia was prevalent (n = 662, 37.9%) and strongly associated with worse clinical outcomes. In patients with worse renal function (eGFR < 60 mL/min per 1.73 m² ), hypochromia was independently associated with primary endpoint (hazard ratio [HR], 1.56; 95% confidence interval [CI], 1.23-1.98; P < 0.001), any-cause hospitalization (HR, 1.43; 95% CI, 1.20-1.71, P < 0.001) and HF hospitalization (HR, 1.40; 95% CI, 1.07-1.84; P = 0.015), whereas no significant association between hypochromia and these outcomes was found in patients with better renal function.

CONCLUSIONS

Among HFpEF patients, hypochromia (i.e. MCHC ≤ 330 g/L) is independently associated with adverse clinical outcomes, especially when in the presence of co-morbidity renal dysfunction.

Missing trial results: analysis of the current publication rate of studies in pediatric dialysis from 2003 to 2020

BACKGROUND

Decision-making in the field of pediatric dialysis requires evidence from clinical trials, but, similar to other fields of pediatric medicine, might be affected by a low trial publication rate.

METHODS

We analyzed the current publication rate, the time to publication, and factors that might be associated with both rate of and time to publication in pediatric dialysis studies registered as completed on ClinicalTrials.gov from 2003 until November 2020.

RESULTS

Fifty-three respective studies were identified. These enrolled 7287 patients in total. 28 of 53 studies (52.8%) had results available. We identified a median time to publication of 20.5 months (range, 3-67). Studies published after the FDA Amendments Act establishment in 2007 were published faster (P = 0.025). There was no trend toward a higher publication rate of studies completed more recently (P = 0.431). 26 of 53 studies (49.1%) focused on medication and control of secondary complications of kidney failure. 12 of 53 studies (22.6%) enrolled only children, were published faster (P = 0.029) and had a higher 5-year publication rate (P = 0.038) than studies enrolling both children and adults. 25 of 53 studies (47.1%) were co-funded by industry. These were published faster (P = 0.025).

CONCLUSIONS

Currently, only 52.8% of all investigated studies in pediatric dialysis have available results, and the overall median time to publication did not meet FDA requirements. This might introduce a publication bias into the field, and it might negatively impact clinical decision-making in this critical subspecialty of pediatric medicine. A higher resolution version of the Graphical abstract is available as Supplementary information.

Prevalence and risk factors for functional iron deficiency in children with chronic kidney disease

INTRODUCTION

Anemia in chronic kidney disease (CKD) is multifactorial. The presence of functional iron deficiency (FID), whereby, there is a block in the transport of iron from macrophage to erythroid marrow is one possible etiology. In this study, we aim to assess the prevalence and risk factors of FID in pediatric CKD.

METHODS

A cross-sectional study was performed from March to December 2018, after obtaining Institute Ethical Clearance. Children aged ≤ 12 years with CKD, with or without iron supplementation who consented were enrolled. Patients on erythropoietin or on maintenance dialysis were excluded. Details of patients and diseases characteristics were recorded. Various laboratory parameters including complete blood count, red blood cell indices, hypochromic RBC, reticulocyte hemoglobin content, and serum ferritin were measured. Appropriate statistical tests were applied.

RESULTS

Out of 174 children, 127 (73%) had structural kidney disease as an etiology of CKD, and 110 (63%) had anemia. Prevalence of anemia was 44%, 43%, 74%, 64% and 92% in CKD stage 1, 2, 3, 4 and 5, respectively. Absolute iron deficiency was found in 66 (38%) even when some children were already on iron supplementation. FID was seen in 44 (25%) and on multivariate analysis, lower estimated glomerular filtration rate and mineral bone disease are associated risk factors.

CONCLUSION

FID is present in one-fourth of our CKD cohort. It should be considered when the response to adequate measures of improving hemoglobin level fails. More studies are required to know its impact on short-term and long-term patient-related outcomes such as quality of life and mortality.

Urinary phthalate metabolites and anemia: Findings from the Korean National Environmental Health Survey (2015-2017)

BACKGROUND

Several animal studies have suggested an association between phthalate exposure and decreased hemoglobin levels. To address the lack of epidemiological evidence, we evaluated the association between urinary phthalate metabolite concentrations and hematologic indices by using nationally representative data from Korea.

METHODS

Data from 3722 adults included in the third stage (2015-2017) of the Korean National Environmental Health Survey (KONEHS) were used. The association between various urinary phthalate metabolites and hematologic indices (hemoglobin, hematocrit, mean corpuscular volume [MCV], and red blood cell [RBC], white blood cell [WBC], and platelet counts) was evaluated using linear regression analysis adjusted for potential confounders. Sex-stratified analysis was performed.

RESULTS

All urinary phthalate metabolites were negatively associated with hemoglobin levels. A two-fold increase in urinary mono-(2-ethyl-5-carboxy-pentyl) phthalate (MECPP), mono-carboxyoctyl phthalate (MCOP), mono-carboxyonyl phthalate (MCNP), and mono-(3-carboxypropyl) phthalate (MCPP) levels was associated with a -0.099 g/dL (95% confidence interval (CI), -0.137 to -0.060), -0.116 g/dL (95% CI, -0.156 to -0.076), -0.111 g/dL (95% CI, -0.154 to -0.068), and -0.144 g/dL (95% CI, -0.198 to -0.089) change in hemoglobin levels, respectively. The RBC count and MCV showed negative and positive associations, respectively, with urinary phthalate metabolite concentrations. WBC counts were positively associated with MECPP, MCOP, MCNP, and MCPP levels, whereas the platelet count showed no association with urinary phthalate metabolites.

CONCLUSIONS

Urinary phthalate metabolite concentration showed a negative association with hemoglobin level. Since this was a cross-sectional study, further longitudinal and experimental studies are needed to identify a clear causal linkage and the pathological mechanism underlying phthalate exposure and anemia.

Chronic Kidney Disease in Children

Chronic kidney disease (CKD) in children occurs mostly due to congenital anomalies of kidney and urinary tract and hereditary diseases. For advanced cases, a multidisciplinary team is needed to manage nutritional requirements and complications such as hypertension, hyperphosphatemia, proteinuria, and anemia. Neurocognitive assessment and psychosocial support are essential. Maintenance dialysis in children with end-stage renal failure has become the standard of care in many parts of the world. Children younger than 12 years have 95% survival after 3 years of dialysis initiation, whereas the survival rate for children aged 4 years or younger is about 82% at one year."

Biosimilar erythropoietin in anemia treatment (BEAT)-Efficacy and safety of a 1:1 dose conversion from EPREX® to EPIAO® in patients with end-stage renal disease on hemodialysis: A prospective, randomized, double blind, parallel group study

BACKGROUND

EPREX®/ERYPO®/PROCRIT® (epoetin alfa, Janssen-Cilag GmbH) was the first available recombinant human erythropoietin (rHuEPO) and was universally reference product as per the recommendation provided by European Medicines Agency. EPIAO® is a biosimilar formulation of EPREX®, and making it a 1:1 dose conversion from EPREX® according to recommendation of European Medicines Agency. This study evaluated the clinical efficacy and safety of EPIAO® in subjects with end-stage renal disease receiving hemodialysis after intravenous administration.

METHODS

This study was a multicenter, prospective, randomized, double-blind, parallel-group, 2-cohort, maintenance phase, therapeutic equivalence study to evaluate a 1:1 dose conversion from EPREX® to EPIAO® in terms of clinical efficacy and safety that was conducted at 20 sites in 2 countries in patients with end-stage renal disease on hemodialysis. Eligible subjects were treated with EPREX® (reference product of epoetin) for a period of at least 3 months before the treatment period, and then were randomly assigned to the group of EPREX® or EPIAO®. Primary endpoints were mean absolute change in hemoglobin level and mean absolute change in weekly epoetin dosage from baseline to 6 months after treatment with EPIAO®/EPREX® in parallel groups.

RESULTS

A total of 200 people received the random intervention and were included in the safety set. After 6, 9, and 12 months of treatment with EPIAO® or EPREX®, there were no significant differences in the hemoglobin levels of the 2 groups compared with baseline. The 95% confidence interval for the treatment difference was within the predetermined acceptable range: ±0.5 g/dL. There were no significant differences in the epoetin dosage of the 2 groups compared with the baseline. The 95% confidence interval for the treatment difference was within the predetermined acceptable range: ± 45 IU/kg. There were no significant differences in the incidence of adverse events between the EPIAO® and EPREX® groups. Most adverse events were mild to moderate and were reverted/resolved.

CONCLUSION

EPIAO® demonstrated promising effectiveness and manageable safety in patients with end-stage renal disease on hemodialysis.

A review of ferric citrate clinical studies, and the rationale and design of the Ferric Citrate and Chronic Kidney Disease in Children (FIT4KiD) trial

Pediatric chronic kidney disease (CKD) is characterized by many co-morbidities, including impaired growth and development, CKD-mineral and bone disorder, anemia, dysregulated iron metabolism, and cardiovascular disease. In pediatric CKD cohorts, higher circulating concentrations of fibroblast growth factor 23 (FGF23) are associated with some of these adverse clinical outcomes, including CKD progression and left ventricular hypertrophy. It is hypothesized that lowering FGF23 levels will reduce the risk of these events and improve clinical outcomes. Reducing FGF23 levels in CKD may be accomplished by targeting two key stimuli of FGF23 production-dietary phosphate absorption and iron deficiency. Ferric citrate is approved for use as an enteral phosphate binder and iron replacement product in adults with CKD. Clinical trials in adult CKD cohorts have also demonstrated that ferric citrate decreases circulating FGF23 concentrations. This review outlines the possible deleterious effects of excess FGF23 in CKD, summarizes data from the adult CKD clinical trials of ferric citrate, and presents the Ferric Citrate and Chronic Kidney Disease in Children (FIT4KiD) study, a randomized, placebo-controlled trial to evaluate the effects of ferric citrate on FGF23 in pediatric patients with CKD stages 3-4 (ClinicalTrials.gov Identifier NCT04741646).

Unmet needs about iron deficiency in peritoneal dialysis: a Delphi consensus panel

Background

Anaemia and iron deficiency (ID) are common in chronic kidney disease (CKD) patients and related to outcomes. There is growing interest about the role of iron supplementation in CKD, particularly ferric carboxymaltose (FCM), also in relation to the use of erythropoiesis stimulating agents (ESAs). Despite a greater knowledge on ID management in patients receiving haemodialysis, a paucity of data exists about peritoneal dialysis (PD). Furthermore, the aim of this paper is to provide the results of a nationwide Italian survey about ID in PD using the Delphi method.

Methods

A list of 16 statements (48 items) was developed about four main topics: (1) approach to iron therapy in PD; (2) management experience about iron therapy in PD; (3) ESA and iron in PD; (4) pharmacoeconomic impact. Using the Delphi methodology, the survey was distributed online to 36 Italian nephrologists with expertise in PD, who rated their level of agreement with each item on a 5-point Likert scale. Consensus was predefined as more than 66% of the panel agreeing/disagreeing with any given statement.

Results

Twenty-five experts (70%) answered the survey. 35 items (73%) achieved a consensus (8 negative and 27 positive). In particular, the diagnosis of ID is widely known, but some doubts exist about how frequently test it. The use of I.V. iron seems to be routinary and can save money reducing the administration of ESAs. However, internal protocols are welcome.

Conclusions

Expert PD nephrologists know well the problem of ID and feel the necessity of shared protocols to optimize the iron therapy and consequently the use of ESAs.

Erythropoietin in children with hemolytic uremic syndrome: a pilot randomized controlled trial

BACKGROUND

The efficacy of recombinant human erythropoietin (rHuEPO) in sparing red blood cell (RBC) transfusions in children with hemolytic uremic syndrome related to Shiga toxin-producing Escherichia coli (STEC-HUS) is uncertain.

METHODS

We conducted a pilot randomized controlled open trial between December 2018 and January 2021. Children were randomized to the intervention (subcutaneous rHuEPO 50 U/kg three times weekly until discharge + RBC transfusion if hemoglobin ≤ 7 g/dL and/or hemodynamic instability) or to the control arm (RBC transfusion if hemoglobin ≤ 7 g/dL and/or hemodynamic instability). Primary outcome was the number of RBC transfusions received during hospitalization. Secondary outcomes were to explore whether baseline EPO levels were adequate to the degree of anemia, to correlate selected acute phase parameters with the number of RBC transfusions, and to assess possible adverse events.

RESULTS

Twelve patients per arm were included; they were comparable at recruitment and throughout the disease course. Median number of RBC transfusions was similar between groups (1.5, p = 0.76). Most patients had baseline EPO levels adequate to the degree of anemia, which did not correlate with the number of transfusions (r = 0.19, p = 0.44). Conversely, baseline (r = 0.73, p = 0.032) and maximum lactic dehydrogenase levels (r = 0.78, p = 0.003), creatinine peak (r = 0.71, p = 0.03) and dialysis duration (r = 0.7, p = 0.04) correlated significantly with RBC requirements. No side effects were recorded.

CONCLUSION

In children with STEC-HUS, the administration of rHuEPO did not reduce the number of RBC transfusions. Larger studies addressing higher doses and similar severity of kidney failure at rHuEPO initiation (e.g. at start of dialysis) are warranted.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03776851. A higher resolution version of the Graphical abstract is available as Supplementary information.

Anemia in Pediatric Kidney Transplant Recipients-Etiologies and Management

Posttransplant anemia (PTA) is a common complication of pediatric kidney transplantation, with a prevalence ranging from 22 to 85%. PTA is categorized as early (within 6 months posttransplant) and late (>6 months posttransplant). Early PTA is typically associated with surgical blood losses and iron deficiency. Late PTA primarily results from graft dysfunction; however, iron deficiency, drug toxicity, and posttransplant inflammation also play a role. PTA is more severe compared with the anemia in glomerular-filtration-rate matched patients with native chronic kidney disease. Treatment of PTA is directed toward the underlying cause. Erythropoiesis stimulating agents (ESA) are effective; however, their use is limited in the transplant setting. Timely diagnosis and treatment of PTA are vital to prevent long-term adverse outcomes in pediatric transplant recipients.

Growth hormone treatment in the pre-transplant period is associated with superior outcome after pediatric kidney transplantation

BACKGROUND

Recombinant human growth hormone (rhGH) is frequently used for treatment of short stature in children with chronic kidney disease (CKD) prior to kidney transplantation (KT). To what extent this influences growth and transplant function after KT is yet unknown.

METHODS

Post-transplant growth (height, sitting height, leg length) and clinical parameters of 146 CKD patients undergoing KT before the age of 8 years, from two German pediatric nephrology centers, were prospectively investigated with a mean follow-up of 5.56 years. Outcome in patients with (rhGH group) and without (non-prior rhGH group) prior rhGH treatment was assessed by the use of linear mixed-effects models.

RESULTS

Patients in the rhGH group spent longer time on dialysis and less frequently underwent living related KT compared to the non-prior rhGH group but showed similar height z-scores at the time of KT. After KT, steroid exposure was lower and increments in anthropometric z-scores were significantly higher in the rhGH group compared to those in the non-prior rhGH group, although 18% of patients in the latter group were started on rhGH after KT. Non-prior rhGH treatment was associated with a faster decline in transplant function, lower hemoglobin, and higher C-reactive protein levels (CRP). After adjustment for these confounders, growth outcome did statistically differ for sitting height z-scores only.

CONCLUSIONS

Treatment with rhGH prior to KT was associated with superior growth outcome in prepubertal kidney transplant recipients, which was related to better transplant function, lower CRP, less anemia, lower steroid exposure, and earlier maturation after KT. A higher resolution version of the Graphical abstract is available as Supplementary information.

Prevalence and Associated Factors of Kidney Dysfunction in Patients with Hypertension and/or Diabetes Mellitus from a Primary Care Population in Northwest China

Purpose

The burden of kidney dysfunction (KD) is rapidly increasing in developing countries due to an ongoing epidemic of hypertension and diabetes. We aimed to evaluate the prevalence and associated factors of KD among population with hypertension and/or diabetes from primary care setting.

Methods

This study was part of a cross-sectional study conducted in Northwest China, which aimed to investigate the epidemiological status of hypertension and other chronic noninfectious diseases. Subjects aged ≥18 years old with hypertension and/or diabetes were included in this study. KD was defined as estimated glomerular filtration rate (eGFR) less than 60 mL/min/1.73m². Least absolute shrinkage and selection operator and multivariable logistic regression were used to identify factors associated with KD. Sensitivity analysis was performed by comparing the results of different estimated equations for GFR.

Results

A total of 8899 participants with hypertension and/or diabetes were included. Prevalence of KD was 8.69% (n=144) among patients with both hypertension and DM, 3.36% (n=198) among patients with only hypertension, and 5.22% (n=70) among patients with only diabetes. Women showed higher prevalent KD than men. Modifiable factors independently associated with KD among patients with hypertension and/or diabetes included physical activity, duration of hypertension or DM, anemia, fasting plasma glucose and triglyceride. Results of different estimated equations showed similar trends of difference in the prevalence of KD among groups.

Conclusion

KD is common in patients with hypertension and/or DM in Northwest China. More attention should be paid to high-risk patients, especially to those with co-existence of hypertension and DM. Control of blood glucose and triglyceride may further improve KD management in this patient population.

Increased severity of anemia is associated with postoperative complications following primary total shoulder arthroplasty

BACKGROUND

Anemia has been demonstrated as a modifiable risk factor for postoperative complications following various types of primary and revision total joint arthroplasties. However, at present, we are not aware of any studies assessing postoperative complications following total shoulder arthroplasty (TSA) in patients with varying severity of anemia. The purpose of this study was to determine the influence of preoperative anemia severity on 30-day postoperative complications following primary TSA.

METHODS

Adult patients undergoing primary TSA from 2012 to 2018 were identified in the National Surgical Quality Improvement Program database. Patients undergoing TSA were substratified into 3 cohorts: nonanemia (hematocrit >36% for women, >39% for men), mild anemia (hematocrit 33%-36% for women, 33%-39% for men), and moderate to severe anemia (hematocrit <33% for both women and men), based on World Health Organization definitions of anemia. In this analysis, 30-day wound, cardiac, pulmonary, renal, and thromboembolic complications, as well as sepsis, mortality, postoperative transfusion, extended length of stay, and reoperation were assessed. Bivariate analyses, including χ² and analysis of variance, and multivariable logistical regression were performed.

RESULTS

Of 13,921 total patients undergoing TSA, 11,330 patients (81.4%) did not have anemia, 1934 (13.9%) had mild anemia, and 657 (4.7%) had moderate to severe anemia. Following adjustment, patients with mild anemia were more likely to have a postoperative blood transfusion (odds ratio [OR] 4.7, P < .001), extended length of stay (OR 1.7, P = .002), and reoperation (OR 1.5, P = .028). Patients with moderate to severe anemia were at increased risk of cardiac complications (OR 3.0, P = .012), pulmonary complications (OR 2.2, P = .015), postoperative blood transfusion (OR 23.8, P < .001), extended length of stay (OR 6.6, P < .001), reoperation (OR 2.2, P = .003), and death (OR 3.8, P = .034).

CONCLUSION

From mild anemia to moderate to severe anemia, there was a stepwise and approximately 2-fold increase in the odds of postoperative complications for patients undergoing primary TSA. Patients with moderate to severe anemia should be medically optimized before they undergo TSA.

Maternal and fetal outcomes of pregnancy in chronic kidney disease: diagnostic challenges, surveillance and treatment throughout the spectrum of kidney disease

Pregnancy requires several physiological adaptations from the maternal organism, including modifications in the glomerular filtration rate and renal excretion of several products. Chronic kidney disease (CKD) can negatively affect these modifications and consequently is associated with several adverse maternal and fetal adverse outcomes (gestational hypertension, progression of renal disease, pre-eclampsia, fetal growth restriction, and preterm delivery). A multidisciplinary vigilance of these pregnancies is essential in order to avoid and/or control the harmful effects associated with this pathology. Dialysis and transplantation can decrease the risks of maternal and fetal complications, nonetheless, the rates of complications remain high comparing with a normal pregnancy. Several recent developments in this area have improved quality and efficacy of treatment of pregnant women with CKD. This article summarizes the most recent literature about CKD and pregnancy.

MO555ASSESSMENT OF HEALTH-RELATED QUALITY OF LIFE (HRQOL) MEASURES FOR PAEDIATRIC PATIENTS WITH ANAEMIA OF CHRONIC KIDNEY DISEASE (CKD)

Background and Aims

Anaemia is a common complication of CKD in children that is associated with adverse clinical outcomes, including poor physical functioning for patients and lower HRQoL for patients and caregivers.1 Given the subjective nature of the disease, instruments that measure patient- and/or observer-reported outcomes (PROs/ObsROs), by collecting information about symptom severity and HRQoL, could be of value to assess treatment benefit. We determined which aspects of anaemia of CKD and its treatments are important for paediatric patients and their caregivers, and examined which PRO/ObsRO instruments comprehensively capture patients’ and caregivers’ experiences.

Method

A targeted literature review and database search were performed to find a) qualitative and quantitative studies of symptoms and related health outcomes in paediatric patients with anaemia of CKD; b) related clinical practice guidelines; and c) HRQoL information in product labelling. Study outcomes were used to develop a structured representation of health outcomes concepts and issues (‘conceptual model’) capturing the symptoms, perceptions of treatment and impact on HRQoL of anaemia of CKD, from the perspective of both paediatric patients and their caregivers. PRO and ObsRO instruments were identified from published quantitative studies and ongoing clinical trials, and a selection was then critically assessed to determine their content validity and whether their psychometric properties adequately covered the conceptual model domains.

Results

The conceptual model captured shortness of breath, fatigue and headaches as the most important symptoms experienced by paediatric patients with anaemia of CKD. Concerns regarding disease management included medical interventions, fear associated with interventions and the need for information about the disease. Disease symptoms and their management impacted seven HRQoL domains, namely physical, emotional and social functioning; activities of daily living; and effects on family, work and caregivers (Figure).

The quantitative search of published studies identified 20 unique instruments; of these, the most frequently used was Pediatric Quality of Life Inventory™ (PedsQL) Version 4.0. Ongoing clinical trials used 14 unique instruments, of which only EQ-5D-Y was used in more than one study. Two clinical practice guidelines (National Institute for Health and Care Excellence and Kidney Disease: Improving Global Outcomes) supported measurements of HRQoL, symptoms, patient preferences and school attendance/performance, but they did not advocate use of any specific instruments. No HRQoL product labelling information was identified.

Based on the conceptual model, the literature review results and age group coverage, five instruments were selected for critical appraisal: PedsQL, PedsQL Infant Scales, PedsQL Multidimensional Fatigue Scale, PedsQL v3.0 End Stage Renal Disease module, and EQ-5D-Y. Between them, these instruments provided complete coverage of the impact of fatigue and headaches, and partial coverage of the effects on physical functioning, activities of daily living, emotional functioning and social functioning. None of these instruments measured the impact of shortness of breath, and there was no coverage of the consequences for work or the family’s/caregivers’ HRQoL.

Conclusion

Anaemia of CKD affects many HRQoL domains for paediatric patients and their caregivers. While current PRO/ObsRO instruments partially address these impacts, no single instrument in our assessment measured all symptoms and domains of interest to patients and caregivers. Multiple instruments should be included in clinical studies to capture symptoms and HRQoL important to patients, and adequate measurement of the effects of anaemia on work or the family’s/caregivers’ HRQoL might require development of a new instrument.

Identifying key predictors of mortality in young patients on chronic haemodialysis-a machine learning approach

BACKGROUND

The mortality risk remains significant in paediatric and adult patients on chronic haemodialysis (HD) treatment. We aimed to identify factors associated with mortality in patients who started HD as children and continued HD as adults.

METHODS

The data originated from a cohort of patients <30 years of age who started HD in childhood (≤19 years) on thrice-weekly HD in outpatient DaVita dialysis centres between 2004 and 2016. Patients with at least 5 years of follow-up since the initiation of HD or death within 5 years were included; 105 variables relating to demographics, HD treatment and laboratory measurements were evaluated as predictors of 5-year mortality utilizing a machine learning approach (random forest).

RESULTS

A total of 363 patients were included in the analysis, with 84 patients having started HD at <12 years of age. Low albumin and elevated lactate dehydrogenase (LDH) were the two most important predictors of 5-year mortality. Other predictors included elevated red blood cell distribution width or blood pressure and decreased red blood cell count, haemoglobin, albumin:globulin ratio, ultrafiltration rate, z-score weight for age or single-pool Kt/V (below target). Mortality was predicted with an accuracy of 81%.

CONCLUSIONS

Mortality in paediatric and young adult patients on chronic HD is associated with multifactorial markers of nutrition, inflammation, anaemia and dialysis dose. This highlights the importance of multimodal intervention strategies besides adequate HD treatment as determined by Kt/V alone. The association with elevated LDH was not previously reported and may indicate the relevance of blood-membrane interactions, organ malperfusion or haematologic and metabolic changes during maintenance HD in this population.

Oral iron supplementation in patients with chronic kidney disease: Can it be harmful to the gut microbiota?

Patients with chronic kidney disease (CKD) have several pathophysiological alterations, including anemia, one of the first changes in CKD patients. More recently, researchers have observed that the intestinal microbiota alterations are also another complication in these patients. The most common treatment for anemia is oral (mainly ferrous sulfate) or intravenous iron supplementation. Despite being a necessary treatment, recent studies have reported that supplementation with oral iron may increase its availability in the intestine, leading to disturbance in the gut microbiota and also to oxidative stress in the enterocytes, which may change the permeability and the microbiota profile. Although it is a therapy routinely used in patients with CKD, supplementation with oral iron on the gut microbiota has been rarely studied in these patients. Thus, this review will discuss the relationship between iron and the gut microbiota and the possible effects of oral iron supplementation on gut microbiota in patients with CKD.

Epidemiology of Chronic Kidney Disease in Children: A Report from Lithuania

Background and Objectives: The data on the prevalence of chronic kidney disease (CKD) in the pediatric population are limited. The prevalence of CKD ranges from 56 to 74.7 cases per million of the age-related population (pmarp). The most common cause of CKD among children is congenital anomalies of the kidney and urinary tract (CAKUT). With progressing CKD, various complications occur, and end-stage renal disease (ESRD) can develop. The aim of the study was to determine the causes, stage, prevalence, and clinical signs of CKD and demand for RRT (renal replacement therapy) among Lithuanian children in 2017 and to compare the epidemiological data of CKD with the data of 1997 and 2006. Materials and Methods: The data of 172 Lithuanian children who had a diagnosis of CKD (stage 2–5) in 1997 (n = 41), in 2006 (n = 65), and in 2017 (n = 66) were retrospectively analyzed. Physical development and clinical signs of children who had CKD (stage 2–5) in 2017 were assessed. Results: The prevalence of CKD stages 2–5 was 48.0 pmarp in 1997; 88.7 in 2006; and 132.1 in 2017 (p < 0.01). Congenital and hereditary diseases of the kidney in 1997 accounted for 66% of all CKD causes; in 2006, for 70%; and in 2017, for 79%. In 2017, children with CKD stages 4 or 5 (except transplanted children) had hypertension (87.5%) and anemia (50%) (p < 0.01). Children under ≤2 years with CKD were at a 3-fold greater risk of having elevated blood pressure (OR = 3.375, 95% CI: 1.186–9.904). Conclusions: There was no change in the number of children with CKD in Lithuania; however, the prevalence of CKD increased due to reduced pediatric population. CAKUT remains the main cause of CKD at all time periods. Among children with CKD stages 4 or 5, there were more children with hypertension and anemia. In children who were diagnosed with CKD at an early age hypertension developed at a younger age.

Iron Therapy in Chronic Kidney Disease: Days of Future Past

Anemia affects millions of patients with chronic kidney disease (CKD) and prompt iron supplementation can lead to reductions in the required dose of erythropoiesis-stimulating agents, thereby reducing medical costs. Oral and intravenous (IV) traditional iron preparations are considered far from ideal, primarily due to gastrointestinal intolerability and the potential risk of infusion reactions, respectively. Fortunately, the emergence of novel iron replacement therapies has engendered a paradigm shift in the treatment of iron deficiency anemia in patients with CKD. For example, oral ferric citrate is an efficacious and safe phosphate binder that increases iron stores to maintain hemoglobin levels. Additional benefits include reductions in fibroblast growth factor 23 levels and the activation of 1,25 dihydroxyvitamin D. The new-generation IV iron preparations ferumoxytol, iron isomaltoside 1000, and ferric carboxymaltose are characterized by a reduced risk of infusion reactions and are clinically well tolerated as a rapid high-dose infusion. In patients undergoing hemodialysis (HD), ferric pyrophosphate citrate (FPC) administered through dialysate enables the replacement of ongoing uremic and HD-related iron loss. FPC transports iron directly to transferrin, bypassing the reticuloendothelial system and avoiding iron sequestration. Moreover, this paper summarizes recent advancements of hypoxia-inducible factor prolyl hydroxylase inhibitors and future perspectives in renal anemia management.

Extracellular vesicles as regulators of kidney function and disease

Extracellular vesicles (EVs) are small, lipid bilayer-delimited particles of cellular origin that recently gained increasing attention for their potential use as diagnostic biomarkers, and beyond that for their role in intercellular communication and as regulators of homeostatic and disease processes. In acute kidney injury (AKI) and chronic kidney disease (CKD), the potential use of EVs as diagnostic and prognostic markers has been evaluated in a series of clinical studies and contributions to pathophysiologic pathways have been investigated in experimental models. While EV concentrations in biofluids could not distinguish renal patients from healthy subjects or determine disease progression, specific EV subpopulations have been identified that may provide useful diagnostic and prognostic tools in AKI. Specific EV subpopulations are also associated with clinical complications in sepsis-induced AKI and in CKD. Beyond their role as biomarkers, pathophysiologic involvement of EVs has been shown in hemolytic uremic syndrome- and sepsis-induced AKI as well as in cardiovascular complications of CKD. On the other hand, some endogenously formed or therapeutically applied EVs demonstrate protective effects pointing toward their usefulness as emerging treatment strategy in kidney disease.

Anemia after kidney transplantation: Does its basis differ from anemia in chronic kidney disease?

BACKGROUND

Although similar factors play a role in both PTA and anemia in patients with CKD, additional risk factors exist in the pathogenesis of PTA. The present study aimed at comparing anemia and inflammation-related parameters between RTx recipients and CKD patients and elucidating the risk factors of PTA.

METHODS

This single-centered, cross-sectional study consisted of 68 participants: 48 were in the RTx group and 20 were in the CKD group. The CKD patients were comparable to the RTx recipients in terms of age, gender, and eGFR. Serum levels of EPO, hepcidin, and IL-6 were measured by enzyme-linked immunosorbent assays. The ratio of EPO/Hb was calculated to estimate endogenous EPO resistance.

RESULTS

The prevalence of anemia was 46% in the RTx group and 30% in the CKD group (P = .23). RTx recipients had significantly lower Hb (P = .04), higher EPO (P < .001), and ferritin levels (P = .001), and higher EPO/Hb ratios (P < .001); however, CKD patients showed a higher frequency of absolute iron deficiency (P = .008). Neither hepcidin nor IL-6 levels differed between the two groups. Hb level of RTx recipients was correlated with only eGFR (r = .437, P = .002) but not with any of the transplantation-related factors, while Fe level was the only parameter to be correlated with Hb level of CKD patients (r = .622, P = .01).

CONCLUSION

In the present study comparing GFR-matched RTx and CKD patients, lower GFR level appears to be the factor most strongly associated with anemia, and endogenous EPO resistance is among the contributing factors to PTA.

Prussian blue nanoparticles induce myeloid leukemia cells to differentiate into red blood cells through nanozyme activities

Numerous types of diseases cause serious anemia, which is characterized by a significantly decreased number of circulating red blood cells. The key reason is retarded terminal erythroid differentiation, which is largely involved in the downregulation of intracellular reactive oxygen species (ROS) and insufficient iron uptake. Prussian blue nanoparticles (PBNPs) have been demonstrated to be capable of scavenging ROS via multienzyme-like activity and contain the iron element. The aim of this study was to figure out whether PBNPs can induce terminal erythroid differentiation in myeloid leukemia cells K562 and to investigate the underlying mechanisms. Our results showed that PBNPs were taken up by K562 cells, which reduced the intracellular ROS level in the cells, upregulated the late erythroid surface marker GYPA (CD235a) and downregulated the early erythroid surface marker TFRC (CD71), clearly indicating the occurrence of terminal erythroid differentiation. In addition, the cells became smaller in size after incubation with PBNPs, providing strong side evidence that the cells had undergone terminal differentiation. Mechanistic studies indicated that PBNP-induced terminal differentiation was associated with the upregulation of the nuclear transcriptional factor NFE2 and downregulation of GATA1, both of which are closely related to the variation of intracellular ROS levels. In conclusion, PBNPs demonstrated a novel function by effectively inducing terminal erythroid differentiation in myeloid leukemia cells, which is of great significance in improving the blood profiles of anemia patients.

Collagen Hydrolysate Corrects Anemia in Chronic Kidney Disease via Anti-Inflammatory Renoprotection and HIF-2α-Dependent Erythropoietin and Hepcidin Regulation

Anemia is a common chronic kidney disease (CKD) complication contributing to increased morbidity and mortality. Collagen-based traditional Chinese nutraceuticals have long been used in antianemic therapies. This study aims to investigate the therapeutic effectiveness of porcine collagen hydrolysate (CH) and its underlying mechanism in the treatment of renal anemia by using adenine-induced CKD mice, RAW264.7 macrophages, and HepG2 hepatoma cells, with prolyl-hydroxyproline as a reference compound for collagen-derived hydroxyproline-containing di-/tripeptides. CH was found to alleviate renal filtering dysfunction, systemic and kidney inflammation, liver hepcidin overproduction and anemia and to increase erythropoietin production and hypoxia inducible factor (HIF)-2α stability in liver and kidney in CKD mice. Prolyl-hydroxyproline exerted direct anti-inflammatory effects on lipopolysaccharide-activated macrophages and elicited stimulating and inhibiting activities on erythropoietin expression and hepcidin overproduction, respectively, in HepG2 cells by HIF-2α activation. Overall, CH was effective in correcting renal anemia via anti-inflammatory renoprotection and HIF-2α-dependent erythropoietin and hepcidin regulation.