How I treat renal anemia

The influencing factors of the erythropoietin resistance index and its association with all-cause mortality in maintenance hemodialysis patients

Anemia is a common complication of chronic kidney disease with major option treatment of erythropoiesis-stimulating agents (ESAs). This study aimed to investigate the influencing factors of erythropoietin resistance index (ERI) and its association with mortality in maintenance hemodialysis (MHD) patients. Patients enrolled from China Dialysis Outcomes and Practice Patterns Study (DOPPS) 5 were included. ERI was calculated as follows: ESA (IU/week)/weight (kg, post-dialysis)/hemoglobin level (g/dL). The Cox regression model was used to analyze the influencing factors on survival outcomes. Stepwise multivariate logistic regression was used to identify the related risk factors, and subgroup analyses were performed. A total of 1270 MHD subjects (687 males and 583 females) were included, with an average age of 60 (49.0, 71.0) years. All subjects were divided into two groups by the median ERI of 14.03. Multivariate logistic regression showed that dialysis vintage (OR 0.957, 95% CI: 0.929-0.986), white blood cells (OR 0.900, 95% CI: 0.844-0.960), high flux dialyzer use (OR 0.866, 95% CI: 0.755-0.993), body mass index (OR 0.860, 95% CI: 0.828-0.892), males (OR 0.708, 95% CI: 0.625-0.801), and albumin (OR 0.512, 95% CI: 0.389-0.673) had a negative association with high ERI baseline (all p < 0.05). There were 176 (13.9%) deaths in total including 89 cardiac/vascular deaths during follow-up. Cox regression analysis showed that ERI was positively associated with all-cause mortality, especially in some subgroups. ERI was associated with increased all-cause mortality in MHD patients, indicating the possibility of death prediction by ERI. Patients with high ERI warrant more attention.

A nomogram for predicting the risk of treatment failure of roxadustat in peritoneal dialysis with renal anemia

The determinants of roxadustat treatment failure in renal anemia remain elusive. This study sought to develop a nomogram for predicting the risk of treatment failure of roxadustat in peritoneal dialysis (PD) with renal anemia. A retrospective cohort analysis from January 1, 2019, to January 31, 2023, included 204 PD patients with renal anemia, stratified by attainment group (Hb ≥ 110 g/L, n = 103) or non-attainment (Hb < 110 g/L, n = 101) within 1 year treatment. Univariate and multivariate Cox proportional hazards regressions were employed to ascertain predictive factors and construct the nomogram. Nomogram efficacy was evaluated via C-index, time-dependent ROC, calibration plots, and decision curve analysis, with internal validation via tenfold cross-validation and 1000 bootstrap resampling iterations. The study identified PD duration, serum transferrin, cardiovascular comorbidities, and stains as significant predictors. The nomogram demonstrated moderate discrimination at 6 months (AUC: 0.717) and enhanced predictive accuracy at 12 months (AUC: 0.741). The predicted and actual risk probabilities were concordant, with clinical net benefits observed at six-month (8 to 53%) and twelve-month (27 to 84%) risk thresholds. This nomogram is a valuable tool for effectively predicting non-attainment risk and facilitating personalized management of renal anemia in PD patients treated with roxadustat.

Cardiovascular Consequences of Uremic Metabolites: an Overview of the Involved Signaling Pathways

The crosstalk of the heart with distant organs such as the lung, liver, gut, and kidney has been intensively approached lately. The kidney is involved in (1) the production of systemic relevant products, such as renin, as part of the most essential vasoregulatory system of the human body, and (2) in the clearance of metabolites with systemic and organ effects. Metabolic residue accumulation during kidney dysfunction is known to determine cardiovascular pathologies such as endothelial activation/dysfunction, atherosclerosis, cardiomyocyte apoptosis, cardiac fibrosis, and vascular and valvular calcification, leading to hypertension, arrhythmias, myocardial infarction, and cardiomyopathies. However, this review offers an overview of the uremic metabolites and details their signaling pathways involved in cardiorenal syndrome and the development of heart failure. A holistic view of the metabolites, but more importantly, an exhaustive crosstalk of their known signaling pathways, is important for depicting new therapeutic strategies in the cardiovascular field.

Renal function modifies the association between hemoconcentration and outcomes in hospitalized heart failure patients

Evidence-based management of decongestion is lacking in hospitalized heart failure (HHF) patients, especially in patients with impaired renal function. Hemoconcentration is an objective measure of decongestion that portends a favorable prognosis and guides management in HHF patients with preserved renal function. We aim to investigate whether it remains a prognosticator in patients with renal impairment, and to refine the identification of subpopulations who will benefit from hemoconcentration-guided therapy. HHF patients admitted to Heart Failure Center of Fuwai Hospital were consecutively included from December 2006 to June 2018. Patient characteristics were depicted. Relationships between in-hospital hemoconcentration, worsening renal function (WRF), and one-year all-cause mortality were investigated in the total population and compared between renal function groups using survival analysis and cubic splines, with a special focus on renal function-based interactions. The association was further validated in sensitivity analyses. Clinically relevant cut-offs and subpopulations were identified by subpopulation treatment effect pattern plots (STEPP) and subgroup analysis. 3661 participants (30.4% with impaired renal function) were included. Hemoconcentration, reflected by an in-hospital increase in hemoglobin, hematocrit, or a relative reduction in estimated plasma volume from baseline to discharge, was predictive of decreased one-year mortality in the total cohort despite its correlation with higher WRF incidence. The prognostic value of hemoconcentration differed in patients with impaired and preserved renal function. Hemoconcentration was related to a favorable prognosis in patients with preserved renal function (HR, 0.69; 95% CI, 0.53-0.90; P = 0.007), especially in young male patients with New York Heart Association functional class III-IV, reduced ejection fraction, and baseline eGFR > 75 mL/min/1.73m2. Contrarily, impaired renal function patients experienced a higher incidence of WRF, and hemoconcentration was no longer related to outcome (HR, 0.90; 95% CI, 0.64-1.26; P = 0.545), with findings consistent in all clinically relevant subgroups. In HHF patients, the prognostic value of hemoconcentration differs by renal function, and the clinical utility of hemoconcentration is contingent on preserved renal function.

A cross-sectional study of factors influencing left ventricular myocardial work in peritoneal dialysis patients

Objectives

To evaluate myocardial work in peritoneal dialysis patients by pressure-strain loop. To analyze the factors influencing myocardial work in peritoneal dialysis patients with preserved ejection fraction.

Methods

We collected clinical data on possible effects on myocardial work in 105 maintenance peritoneal dialysis patients with preserved ejection fraction and applied ultrasonic pressure-strain loops to obtain the left ventricular global constructive work (GCW), Global work index (GWI), global work waste (GWW), and global work efficiency (GWE) of the patients. Then, the clinical data and myocardial work indices were statistically described and correlated.

Results

Left ventricular hypertrophy was observed in 78 % of peritoneal dialysis patients with left ventricular ejection fraction preservation. There is a correlation between the left ventricular mass index and myocardial work indices (P < 0.05). On multiple linear regression analysis, systolic blood pressure (SBP), IL-6, and hemoglobin correlated with GCW(P < 0.05); SBP and IL-6 correlated with GWI(P < 0.05); homocysteine, SBP, TNF-α, and hemoglobin correlated with GWW(P < 0.05); homocysteine, TNF-α and hemoglobin correlated with GWE (P < 0.05).

Conclusions

Using noninvasive pressure-strain loops to assess left ventricular myocardial work can provide information on cardiac function more consistent with pathophysiological changes than conventional ejection fraction. Hypertension, anemia, hyperhomocysteinemia, and inflammation influence left ventricular myocardial work in peritoneal dialysis patients, and they selectively affect one or more myocardial work indices.

Complex Management of a Geriatric Patient With Multimorbidity: A Case Study

Geriatric patients' distinct physiological responses to diseases and treatments, combined with multimorbidity and polypharmacy, make their care highly challenging. This case study examines the complex management of a 77-year-old female with multiple comorbidities, focusing on the primary issue of splenic hematoma leading to anemia. It highlights the importance of a multidisciplinary approach in geriatric care. The care she received underscores the necessity of ongoing supervision through the Bridge Model of Transitional Care, family engagement in the care process, and a customized, interdisciplinary approach to care. The conclusion of this case has implications for geriatric medicine, primary care, and specialty care, and it also influences strategies to help older adults maintain their functional status and quality of life.

Low hemoglobin levels are associated with Bowman's capsule rupture and peritubular capillaritis in ANCA-associated renal vasculitis: a link of vascular injury to anemia?

BACKGROUND

Anemia in anti-neutrophil cytoplasmic antibody (ANCA)-associated renal vasculitis is a severe complication that predicts renal survival. We here conducted correlative analyses to evaluate correlations of low hemoglobin levels and histopathological characteristics in ANCA-associated renal vasculitis.

METHODS

Fifty-two patients with biopsy-proven ANCA-associated renal vasculitis observed between 2015 and 2020 were retrospectively evaluated. Spearman's correlation was performed to assess correlations, and statistical evaluation was performed by simple and stepwise multivariable regression.

RESULTS

Regarding laboratory anemia parameters, no significant association with serum hemoglobin levels was observed. Serum hemoglobin levels were associated with the estimated glomerular filtration rate in the total cohort (β = 0.539, p < 0.001), and in the MPO-ANCA subgroup (β = 0.679, p = 0.008). Among tubulointerstitial lesions, decreased serum hemoglobin levels correlated with peritubular capillaritis in the whole cohort (β = - 0.358, p = 0.013), and was suggested in the MPO-ANCA subgroup (p = 0.029, r = - 0.446). Regarding glomerular lesions, the prevalence of necrotic glomeruli significantly associated with low serum hemoglobin levels in PR3-ANCA (β = - 0.424, p = 0.028). In the total cohort, a significant correlation between decreased serum hemoglobin levels and the occurrence of diffuse Bowman's capsule rupture was identified (β = - 0.374, p = 0.014), which was implied in the MPO-ANCA subgroup (p = 0.013, r = - 0.546; p = 0.0288, slope = - 16.65).

CONCLUSION

Peritubular capillaritis and Bowman's capsule rupture correlate with low hemoglobin levels; this may indicate that histopathological lesions are linked with inflammatory vascular injury and  relative erythropoietin deficiency in ANCA-associated renal vasculitis.

An updated meta-analysis on the efficacy and safety of hypoxia-inducible factor prolyl hydroxylase inhibitor treatment of anemia in nondialysis-dependent chronic kidney disease

BACKGROUND

Renal anemia, a common complication and threat factor of chronic kidney disease (CKD), has long been treated with injectable erythropoietin-stimulating agents (ESAs). As concerns regarding cardiovascular safety and erythropoietin resistance to ESAs have emerged, alternative therapies are urgently needed. Hypoxia-inducible factor prolyl hydroxylase inhibitor (HIF-PHI), an oral agent, has been proven to be effective in improving renal anemia. However, the effects of HIF-PHIs on nondialysis-dependent CKD (NDD-CKD) have yet to be supported by updated meta-analyses.

METHODS

A meta-analysis of clinical randomized controlled trials (RCTs) on HIF-PHI treatment of NDD-CKD patients based on PubMed, EMBASE, and Cochrane databases as of July 16th, 2023, was conducted. The primary outcomes were the level of hemoglobin (Hb) postintervention and the ratio of Hb responses. Most of the analysis was conducted via RevMan 5.3 software using a random-effects model. Stata (version 15.0) was used to analyze the publication bias.

RESULTS

Twenty-two studies with a total of 7178 subjects in the HIF-PHI group, 3501 subjects in the ESA group and 2533 subjects in the placebo group were enrolled. HIF-PHIs increased the level of Hb and improved iron metabolism but were not inferior to ESAs in terms of safety.

CONCLUSIONS

HIF-PHIs may be a convenient and safe alternative to ESAs in patients with NDD-CKD and anemia.

Infectious Risk and Variability of Hemoglobin Level in Patients Undergoing Hemodialysis

Introduction

In the management of anemia in chronic kidney disease, hemoglobin levels often fall below or exceed target ranges. Past retrospective cohort studies of patients undergoing hemodialysis with conventional erythropoiesis stimulating agents (ESAs) found that hemoglobin level fluctuations predicted mortality and cardiovascular adverse events; long-acting agents were thereafter widely available. An updated validation by a prospective cohort study was needed.

Methods

Using Cox regression models, we evaluated associations between hemoglobin variability and all-cause death, hospitalization, and cardiovascular, thrombotic, or infectious adverse event outcomes in 3063 hemodialysis patients' data from the Japanese Dialysis Outcomes and Practice Patterns Study (J-DOPPS) from 2012 to 2018.

Results

During a median follow-up time of 2.5 years, all-cause mortality was lowest in the first quartile and tended to be higher in groups with greater hemoglobin variability (hazard ratio [HR]: 95% confidence interval for the fourth quartile of an absolute value of hemoglobin variability: 1.44 [0.99-2.08], P for trend = 0.056). Infectious event incidence in these patients was also lower in the first quartile than for the other quartiles (P for trend < 0.01). The association was more pronounced in patients with lower serum ferritin levels or iron supplementation. Cardiovascular and thrombotic event incidence was not associated with hemoglobin variability.

Conclusions

Maintenance hemodialysis patients on ESA treatment with higher hemoglobin variability are at higher risk for all-cause mortality and particularly infectious events.

Effect of different cooking methods on saponin content and hematopoietic effects of Panax notoginseng-steamed chicken on mice

ETHNOPHARMACOLOGICAL RELEVANCE

Panax notoginseng-steamed chicken (PNSC) is a medicinal food with ethnic characteristics developed by the Miao ethnic group in the southeast of Yunnan Province, China. PNSC has been eaten for hundreds of years, and its tonic effect has been widely recognized by the people. However, its cooking conditions and scientific connotation of its effect of toning blood and supplementing deficiency are also lack of in-depth analysis.

AIM OF THE STUDY

To optimize the cooking conditions of Panax notoginseng-steamed chicken (PNSC) and to explore its anemia-improving effects.

MATERIALS AND METHODS

The ratio of P. notoginseng (PN) to chicken and the steaming time were systematically altered, and the PNSC cooking conditions was optimized with the response surface method. By establishing animal models of postpartum blood-deficiency anemia, acute hemorrhagic anemia and myelosuppressive anemia, the blood replenishing effect of PNSC was explored, and the blood replenishing mechanism of PNSC on myelosuppressive anemia was revealed by immunoblotting analyses and histopathological sectioning.

RESULTS

The optimal processing conditions included a ratio of chicken to P. notoginseng of 100:5 and a steaming time of 5.5 h. The amounts of P. notoginseng polysaccharides (PNPS), total protein and blood-enriching P. notoginseng saponins were 44.3 mg/g, 2.48% and 2.04%, respectively. Freeze-dried powder of P. notoginseng steamed chicken soup (FPSC) was found to promote the recovery of routine blood factors and organ indexes in the three models of anemia and to activate the JAK2-STAT5 signaling pathway, induce phosphorylation of JAK2 and STAT5 and normalize the secretion of hematopoietic regulators EPO, IL-3, and TNF-α.

CONCLUSION

FPSC improves the symptoms of anemia in mice, and it plays a role in tonifying blood by activating the JAK2-STAT5 signaling pathway and altering the expression of hematopoiesis-related factors.

Preferred Conformation-Guided Discovery of Potent and Orally Active HIF Prolyl Hydroxylase 2 Inhibitors for the Treatment of Anemia

In this work, we discovered a novel series of prolyl hydroxylase 2 (PHD2) inhibitors with improved metabolic properties based on a preferred conformation-guided drug design strategy. Piperidinyl-containing linkers with preferred metabolic stability were designed to match the dihedral angle of the desired docking conformation in the PHD2 binding site with the lowest energy conformation. Based on the piperidinyl-containing linkers, a series of PHD2 inhibitors with high PHD2 affinity and favorable druggability were obtained. Remarkably, compound 22, with an IC₅₀ of 22.53 nM toward PHD2, significantly stabilized hypoxia-inducible factor α (HIF-α) and upregulated the expression of erythropoietin (EPO). Furthermore, oral administration of 22 dose-dependently stimulated erythropoiesis in vivo. Preliminary preclinical studies showed that 22 has good pharmacokinetic properties and an excellent safety profile, even at 10 times the efficacious dose (200 mg/kg). Taken together, these results indicate that 22 is a promising candidate for anemia treatment.

Targeting the innate repair receptor axis via erythropoietin or pyroglutamate helix B surface peptide attenuates hemolytic-uremic syndrome in mice

Hemolytic-uremic syndrome (HUS) can occur as a systemic complication of infections with Shiga toxin (Stx)-producing Escherichia coli and is characterized by microangiopathic hemolytic anemia and acute kidney injury. Hitherto, therapy has been limited to organ-supportive strategies. Erythropoietin (EPO) stimulates erythropoiesis and is approved for the treatment of certain forms of anemia, but not for HUS-associated hemolytic anemia. EPO and its non-hematopoietic analog pyroglutamate helix B surface peptide (pHBSP) have been shown to mediate tissue protection via an innate repair receptor (IRR) that is pharmacologically distinct from the erythropoiesis-mediating receptor (EPO-R). Here, we investigated the changes in endogenous EPO levels in patients with HUS and in piglets and mice subjected to preclinical HUS models. We found that endogenous EPO was elevated in plasma of humans, piglets, and mice with HUS, regardless of species and degree of anemia, suggesting that EPO signaling plays a role in HUS pathology. Therefore, we aimed to examine the therapeutic potential of EPO and pHBSP in mice with Stx-induced HUS. Administration of EPO or pHBSP improved 7-day survival and attenuated renal oxidative stress but did not significantly reduce renal dysfunction and injury in the employed model. pHBSP, but not EPO, attenuated renal nitrosative stress and reduced tubular dedifferentiation. In conclusion, targeting the EPO-R/IRR axis reduced mortality and renal oxidative stress in murine HUS without occurrence of thromboembolic complications or other adverse side effects. We therefore suggest that repurposing EPO for the treatment of patients with hemolytic anemia in HUS should be systematically investigated in future clinical trials.

Association of Clonal Hematopoiesis of Indeterminate Potential with Worse Kidney Function and Anemia in Two Cohorts of Patients with Advanced Chronic Kidney Disease

BACKGROUND

Clonal hematopoiesis of indeterminate potential (CHIP) is an inflammatory premalignant disorder resulting from acquired genetic mutations in hematopoietic stem cells. This condition is common in aging populations and associated with cardiovascular morbidity and overall mortality, but its role in CKD is unknown.

METHODS

We performed targeted sequencing to detect CHIP mutations in two independent cohorts of 87 and 85 adults with an eGFR<60 ml/min per 1.73m2. We also assessed kidney function, hematologic, and mineral bone disease parameters cross-sectionally at baseline, and collected creatinine measurements over the following 5-year period.

RESULTS

At baseline, CHIP was detected in 18 of 87 (21%) and 25 of 85 (29%) cohort participants. Participants with CHIP were at higher risk of kidney failure, as predicted by the Kidney Failure Risk Equation (KFRE), compared with those without CHIP. Individuals with CHIP manifested a 2.2-fold increased risk of a 50% decline in eGFR or ESKD over 5 years of follow-up (hazard ratio 2.2; 95% confidence interval, 1.2 to 3.8) in a Cox proportional hazard model adjusted for age, sex, and baseline eGFR. The addition of CHIP to 2-year and 5-year calibrated KFRE risk models improved ESKD predictions. Those with CHIP also had lower hemoglobin, higher ferritin, and higher red blood cell mean corpuscular volume versus those without CHIP.

CONCLUSIONS

In this exploratory analysis of individuals with preexisting CKD, CHIP was associated with higher baseline KFRE scores, greater progression of CKD, and anemia. Further research is needed to define the nature of the relationship between CHIP and kidney disease progression.

Carbon Dots as a Potential Therapeutic Agent for the Treatment of Cancer-Related Anemia

Due to the adverse effects of erythropoietin (EPO) on cancer patient survival, it is necessary to develop new agents that can be used to efficiently manage and treat cancer-related anemia. In this study, novel distinctive carbon dots, J-CDs, derived from jujube are designed, synthesized, and characterized. Based on the obtained results, this material comprises sp² and sp³ carbon atoms, as well as oxygen/nitrogen-based groups, and it specifically promotes the proliferation of erythroid cells by stimulating the self-renewal of erythroid progenitor cells in vitro and in vivo. Moreover, J-CDs have no discernible effects on tumor proliferation and metastasis, unlike EPO. Transcriptome profiling suggests that J-CDs upregulate the molecules involved in hypoxia response, and they also significantly increase the phosphorylation levels of STAT5, the major transducer of signals for erythroid progenitor cell proliferation. Overall, this study demonstrates that J-CDs effectively promote erythrocyte production without affecting tumor proliferation and metastasis; thus, they may be promising agents for the treatment of cancer-related anemia.

Treatment of Iron Deficiency Anemia in CKD and End-Stage Kidney Disease

Iron deficiency is common in individuals with chronic kidney disease and plays a major role in the development of anemia. Oral and intravenous iron agents are both available to replete iron in patients with chronic kidney disease diagnosed with iron deficiency. The choice of which agent to use is most often dictated by goals of therapy, tolerability, convenience, and response to prior therapy. Diminished absorption of iron in the gastrointestinal tract and a high incidence of gastrointestinal adverse effects can reduce the efficacy of oral iron agents, necessitating the use of i.v. iron formulations to treat iron deficiency anemia, particularly in patients requiring kidney replacement therapy. Newer oral agents may help to overcome these limitations and help treat iron deficiency in those not requiring kidney replacement therapy. Recent studies have provided new evidence that more aggressive repletion of iron in patients with chronic kidney disease requiring kidney replacement therapy may provide benefits with respect to anemia management and hard clinical outcomes such as cardiovascular disease and survival.