Predictors of erythropoietin use in patients with cardiorenal anaemia syndrome

Objectives

Chronic kidney disease (CKD) and anemia are common in patients with heart failure (HF) – these 3 conditions have been coined the Cardiorenal Anemia Sydrome (CRAS). The National Kidney Foundation Kidney Disease Outcomes Quality Initiative (NKF-K/DOQI) guidelines do not specifically address patients with CRAS, creating uncertainty in erythropoietin (EPO) prescribing. We sought to determine predictors of EPO use in patients with CRAS.

Methods

We conducted a retrospective cohort study at the Veteran’s Affairs Greater Los Angeles Healthcare System (VAGLAHS), a 300+ bed facility that provides primary and tertiary inpatient, and ambulatory care services, between January 1, 2003 to December 31, 2006. A multiple logistic regression model was constructed to identify predictors of EPO use among CRAS patients.

Key findings

Of 2058 patients with CRAS, 213 (10.3%) were prescribed EPO. There were significant differences in baseline characteristics between the EPO and non-EPO groups. The following predictors were found to be associated with EPO prescription: iron supplementation (odds ratio [OR] 52.70, 95% confidence interval [CI] 11.70–237.46), renal clinic appointment (OR 2.60, 95% CI 1.79–3.76), malignancy (OR 1.52, 95% CI 1.07–2.16) and use of hydralazine/nitrates (OR 1.41, 95% CI 1.03–1.92). There was an inverse association found between EPO prescription and baseline hemoglobin (OR 0.61, 95% CI 0.53–0.70) and eGFR (OR 0.96, 95% CI 0.94–0.97).

Conclusion

A small proportion of patients eligible for EPO therapy according to guidelines at the time of the study were prescribed the indicated therapy. Markers of declining renal function or those suggesting need for anemia therapy were identified as EPO predictors.

Anemia in Adenine-Induced Chronic Renal Failure and the Influence of Treatment With Gum Acacia Thereon

Anemia frequently complicates chronic kidney disease (CKD). We investigated here the effect of adenine-induced CKD in rats on erythrocyte count (EC), hematocrit (PCV) and hemoglobin (Hb) concentration, as well as on the activity of L-γ-glutamyl transferase (GGT) and the concentrations of iron (Fe), transferrin (Tf), ferritin (F), total iron binding capacity (TIBC) / unsaturated iron binding capacity (UIBC) and hepcidin (Hp) in serum and erythropoietin (Epo) in renal tissue. Renal damage was assessed histopathologically, and also by measuring the serum concentrations of the uremic toxin indoxyl sulfate (IS), creatinine, and urea, and by creatinine clearance. We also assessed the influence of concomitant treatment with gum acacia (GA) on the above analytes. Adenine feeding induced CKD, accompanied by significant decreases (P<0.05) in EC, PCV, and Hb, and in the serum concentrations of Fe, Tf, TIBC, UIBC and Epo. It also increased Hp and F levels. GA significantly ameliorated these changes in rats with CKD. A general improvement in the renal status of rats with CKD after GA is shown due to its anti-inflammatory and anti-oxidant actions, and reduction of the uremic toxin IS, which is known to suppress Epo production, and this may be a reason for its ameliorative actions on the indices of anemia studied.

Mechanism of erythropoietin regulation by angiotensin II

Erythropoietin (EPO) is the primary regulator of red blood cell development. Although hypoxic regulation of EPO has been extensively studied, the mechanism(s) for basal regulation of EPO are not well understood. In vivo studies in healthy human volunteers and animal models indicated that angiotensin II (Ang II) and angiotensin converting enzyme inhibitors regulated blood EPO levels. In the current study, we found that Ang II induced EPO expression in situ in murine kidney slices and in 786-O kidney cells in culture as determined by reverse transcription polymerase chain reaction. We further investigated the signaling mechanism of Ang II regulation of EPO in 786-O cells. Pharmacological inhibitors of Ang II type 1 receptor (AT1R) and extracellular signal-regulated kinase 1/2 (ERK1/2) suppressed Ang II transcriptional activation of EPO. Inhibitors of AT2R or Src homology 2 domain-containing tyrosine phosphatase had no effect. Coimmunoprecipiation experiments demonstrated that p21Ras was constitutively bound to the AT1R; this association was increased by Ang II but was reduced by the AT1R inhibitor telmisartan. Transmembrane domain (TM) 2 of AT1R is important for G protein-dependent ERK1/2 activation, and mutant D74E in TM2 blocked Ang II activation of ERK1/2. Ang II signaling induced the nuclear translocation of the Egr-1 transcription factor, and overexpression of dominant-negative Egr-1 blocked EPO promoter activation by Ang II. These data identify a novel pathway for basal regulation of EPO via AT1R-mediated Egr-1 activation by p21Ras-mitogen-activated protein kinase/ERK kinase-ERK1/2. Our current data suggest that Ang II, in addition to regulating blood volume and pressure, may be a master regulator of erythropoiesis.

Impact of chronic kidney disease and anemia on physical function in patients with chronic heart failure

OBJECTIVE

The aim of this study was to confirm the effects of chronic kidney disease (CKD) and anemia on physical function and to clarify whether the interaction between CKD and anemia has an additive effect.

DESIGN

Eligible subjects were chronic heart failure (HF) patients who were discharged between March 2007 and August 2009. A total of 102 chronic HF patients (33% females; mean age: 68 ± 14 years) were enrolled in the present study. CKD was defined as an estimated glomerular filtration rate of <60 ml/min/1.73 m(2), and anemia was defined as a hemoglobin level of <12 g/dl in males and of <11 g/dl in females. The Short Physical Performance Battery (SPPB) was used to assess physical function.

RESULTS

The adjusted mean SPPB score was lower in patients with both CKD and anemia than in those with neither of the diseases or with either disease alone (p < 0.05).

CONCLUSION

This study found that CKD and anemia are independently associated with reduced physical function.

Clinical outcomes of erythropoietin use in heart failure patients with anemia of chronic kidney disease

BACKGROUND

Anemia and chronic kidney disease are common disorders in heart failure (HF) patients and are associated with increased morbidity and mortality. This study assessed clinical outcomes associated with erythropoietin (EPO) treatment in this cardiorenal anemia syndrome (CRAS) population.

METHODS AND RESULTS

This was a retrospective cohort study of Veterans Affairs patients with CRAS from January 2003 to December 2006. The primary outcome was a composite of death, acute coronary syndrome (ACS), HF, and stroke. Multiple Cox regression modeling was used to evaluate the outcome in patients prescribed (n = 213) and not prescribed EPO (n = 1845). Adjusted incidence of mortality was statistically significantly higher in EPO than in non-EPO users (33.8% vs 19.7%; hazard ratio 1.40, 95% confidence interval 1.06-1.85; P = .02). The unadjusted composite of cardiovascular events/death was higher in the EPO group, but not statistically significant when adjusted for confounders (P = .12). Crude ACS events were documented in 18.8% and 10.8% patients (P = .001), and stroke events occurred in 22.5% and 18.3% patients (P = .14) in EPO and non-EPO groups, respectively.

CONCLUSIONS

We found that in CRAS patients, EPO use was associated with increased risk of mortality and a trend toward increased cardiovascular events. Therefore, clinicians considering EPO use in CRAS patients should assess whether any potential benefits outweigh the risks of use.

Fasting long-acting natriuretic peptide correlates inversely with metabolic syndrome in kidney transplant patients

The metabolic syndrome (MetS) is a risk factor for posttransplant diabetes mellitus, chronic graft dysfunction, graft loss, occurrence of atherosclerotic events, and patient death among kidney transplantation patients. Long-acting natriuretic peptide (LANP) is among the peptide hormones in atrial natriuretic peptide prohormone. Low levels of natriuretic peptide may lead to reduced lipolysis and excessive weight gain in obese patients. This study was undertaken to evaluate the relationship between MetS and fasting serum LANP concentration among kidney transplanted patients. Fasting blood samples were obtained from 69 kidney recipients. The MetS and its components were defined using the diagnostic criteria of the International Diabetes Federation. Fasting LANP levels were measured using a commercial enzyme immunoassay kit. The prevalence rate of MetS was 20.3% (14/69). Fasting LANP level negatively correlated with MetS among these patients (P = .010). Using univariate linear regression analysis, serum LANP values were negatively correlated with hemoglobin (r = -0.252; P = .037), and positively correlated with blood urea nitrogen (r = 0.254; P = .035) and creatinine (r = 0.311; P = .009). Multivariate forward stepwise linear regression analysis of the significant variables revealed that creatinine (R(2) change = 0.097; P = .009) was an independent predictor of fasting serum LANP concentration among kidney transplanted patients. Serum LANP concentration correlates inversely with MetS; for these patients, creatinine is an independent predictor of the serum LANP value.

Cardiorenal syndrome type 1: pathophysiological crosstalk leading to combined heart and kidney dysfunction in the setting of acutely decompensated heart failure

Cardiorenal syndrome (CRS) type 1 is characterized as the development of acute kidney injury (AKI) and dysfunction in the patient with acute cardiac illness, most commonly acute decompensated heart failure (ADHF). There is evidence in the literature supporting multiple pathophysiological mechanisms operating simultaneously and sequentially to result in the clinical syndrome characterized by a rise in serum creatinine, oliguria, diuretic resistance, and in many cases, worsening of ADHF symptoms. The milieu of chronic kidney disease has associated factors including obesity, cachexia, hypertension, diabetes, proteinuria, uremic solute retention, anemia, and repeated subclinical AKI events all work to escalate individual risk of CRS in the setting of ADHF. All of these conditions have been linked to cardiac and renal fibrosis. In the hospitalized patient, hemodynamic changes leading to venous renal congestion, neurohormonal activation, hypothalamic-pituitary stress reaction, inflammation and immune cell signaling, systemic endotoxemic exposure from the gut, superimposed infection, and iatrogenesis all contribute to CRS type 1. The final common pathway of bidirectional organ injury appears to be cellular, tissue, and systemic oxidative stress that exacerbate organ function. This review explores in detail the pathophysiological pathways that put a patient at risk and then effectuate the vicious cycle now recognized as CRS type 1.