Serum albumin is strongly associated with erythropoietin sensitivity in hemodialysis patients

Development and validation of a postoperative bleeding complications prediction model in infective endocarditis

OBJECTIVES

Bleeding complications are one of the most serious postoperative complications after cardiac surgery and are associated with high mortality, especially in patients with infective endocarditis (IE). Our objectives were to identify the risk factors and develop a prediction model for postoperative bleeding complications in IE patients.

METHODS

The clinical data of IE patients treated from October 2013 to January 2022 were reviewed. Multivariate logistic regression analysis was used to evaluate independent risk factors for postoperative bleeding complications and develop a prediction model accordingly. The prediction model was verified in a temporal validation cohort. The performance of the model was evaluated in terms of its discrimination power, calibration, precision, and clinical utility.

RESULTS

A total of 423 consecutive patients with IE who underwent surgery were included in the final analysis, including 315 and 108 patients in the training cohort and validation cohort, respectively. Four variables were selected for developing a prediction model, including platelet counts, systolic blood pressure, heart failure and vegetations on the mitral and aortic valves. In the training cohort, the model exhibited excellent discrimination power (AUC = 0.883), calibration (Hosmer-Lemeshow test, P = 0.803), and precision (Brier score = 0.037). In addition, the model also demonstrated good discrimination power (AUC = 0.805), calibration (Hosmer-Lemeshow test, P = 0.413), and precision (Brier score = 0.067) in the validation cohort.

CONCLUSIONS

We developed and validated a promising risk model with good discrimination power, calibration, and precision for predicting postoperative bleeding complications in IE patients.

LRG1 Associates with Iron Deficiency Anemia Markers in Adolescents

Leucine-rich α-2 glycoprotein1 (LRG1) has been shown to be associated with several health conditions; however, its association with iron deficiency anemia, especially in children, has not been previously explored. In this study, we investigated the association between LRG1 and several iron deficiency anemia markers, including hemoglobin (Hb), albumin, red cell distribution width (RDW), iron, ferritin, and Hb transferrin saturation. A total of 431 participants were included in this analysis aged between 11 and 14 years. Higher LRG1 levels were observed in children diagnosed with anemia [31.1 (24.6, 43.2) µg/mL] compared to non-anemic children [29.2 (22.7-35.95) µg/mL]. Statistically significant differences of LRG1 level across the three groups (tertiles) of Hb, iron, transferrin saturation, albumin, RDW, ferritin, and WBC were observed. Strong negative correlations were observed between LRG1 and Hb (Spearman's rho = -0.11, p = 0.021), albumin (Spearman's rho = -0.24, p < 0.001), iron (Spearman's rho = -0.25, p < 0.001), and Hb transferrin saturation (Spearman's rho = -0.24, p < 0.001), whereas circulating LRG1 levels were positively associated with RDW (Spearman's rho = 0.21, p < 0.001). In conclusion, our findings demonstrate for the first time the strong association between iron deficiency anemia markers and LRG1 in otherwise healthy school-aged children. However, further studies are needed to corroborate those results and to look for similar associations in other population subgroups.

Phase angle and extracellular water-to-total body water ratio estimated by bioelectrical impedance analysis are associated with levels of hemoglobin and hematocrit in patients with diabetes

Background

Anemia is one of the common complications of diabetes and is associated with mortality. Phase angle (PhA), ratio of extracellular water to total body water (ECW/TBW) and skeletal muscle mass index (SMI) estimated by bioelectrical impedance analysis (BIA) have been used as prognostic indicators for various chronic diseases and frailty. We aimed to clarify the clinical significance of PhA, ECW/TBW and SMI for anemia in patients with diabetes.

Materials and methods

The values of PhA, ECW/TBW and SMI were estimated by a portable BIA device and blood samples were collected in 371 Japanese patients with diabetes. The relationships of PhA, ECW/TBW and SMI with hemoglobin (Hgb) and hematocrit (Hct) were statistically evaluated.

Results

In simple linear regression analysis, PhA and SMI were positively correlated with Hgb and Hct levels in total subjects, male subjects and female subjects. In contrast, ECW/TBW was negatively correlated with Hgb and Hct levels regardless of sex. Multivariate regression analysis showed that both PhA and ECW/TBW but not SMI independently contributed to Hgb and Hct levels after adjustment of clinical confounding factors in both males and females.

Conclusions

PhA and ECW/TBW but not SMI were associated with levels of Hgb and Hct in patients with diabetes. Therefore, aberrant values of PhA and ECW/TBW suggest a risk of anemia in diabetic patients.

Clinical relevance of abstruse transport phenomena in haemodialysis

Haemodialysis (HD) utilizes the bidirectional properties of semipermeable membranes to remove uraemic toxins from blood while simultaneously replenishing electrolytes and buffers to correct metabolic acidosis. However, the nonspecific size-dependent transport across membranes also means that certain useful plasma constituents may be removed from the patient (together with uraemic toxins), or toxic compounds, e.g. endotoxin fragments, may accompany electrolytes and buffers of the dialysis fluids into blood and elicit severe biological reactions. We describe the mechanisms and implications of these undesirable transport processes that are inherent to all HD therapies and propose approaches to mitigate the effects of such transport. We focus particularly on two undesirable events that are considered to adversely affect HD therapy and possibly impact patient outcomes. Firstly, we describe how loss of albumin (and other essential substances) can occur while striving to eliminate larger uraemic toxins during HD and why hypoalbuminemia is a clinical condition to contend with. Secondly, we describe the origins and mode of transport of biologically active substances (from dialysis fluids with bacterial contamination) into the blood compartment and biological reactions they elicit. Endotoxin fragments activate various proinflammatory pathways to increase the underlying inflammation associated with chronic kidney disease. Both phenomena involve the physical as well as chemical properties of membranes that must be selected judiciously to balance the benefits with potential risks patients may encounter, in both the short and long term.

The relationship between FGF23 and anemia in HD and renal transplant patients

PURPOSE

Recent studies claim that FGF23 is also associated with anemia and inflammation. In this study, the relationship between FGF23 and anemia in hemodialysis (HD) and renal transplantation patients (RTx patients) patients was investigated.

METHODS

This was a cross-sectional study involving 40 RTx patients (13 females, 27 males; mean age, 45.93 ± 12.49 years) who had transplantation at least 6 months before, 25 HD patients (12 females, 13 males; mean age, 54.72 ± 15.5 years), and 20 healthy control subjects (13 females, 7 males; mean age, 36.7 ± 9.38 years). FGF23 was studied using Elisa method. Parameters such as iron, ferritin, total iron binding capacity, and transferrin saturation were assessed.

RESULTS

FGF23 level was significantly higher in HD patients when compared with the RTx patients and control groups. In the bivariate correlation analysis, hemoglobin was positively correlated with albumin (r = 0.681, p = 0.000), ferritin (r = 0.446, p = 0.043), and negatively correlated with CRP (r = - 0.476, p = 0.016) and FGF23 (r = 0.493, p = 0.043). FGF23 was found to be an independent predictor of decreased hemoglobin in HD patients. In addition, this association was observed to disappear after transplantation.

CONCLUSION

While FGF23 is closely related to hemoglobin levels in HD patients, we have shown that this relationship disappears after transplantation.

Population exposure-efficacy and exposure-safety analyses for rucaparib in patients with recurrent ovarian carcinoma from Study 10 and ARIEL2

OBJECTIVE

To evaluate correlations between rucaparib exposure and selected efficacy and safety endpoints in patients with recurrent ovarian carcinoma using pooled data from Study 10 and ARIEL2.

METHODS

Efficacy analyses were limited to patients with carcinomas harboring a deleterious BRCA1 or BRCA2 mutation who had received ≥2 prior lines of chemotherapy. Safety was evaluated in all patients who received ≥1 rucaparib dose. Steady-state daily area under the concentration-time curve (AUCss) and maximum concentration (Cmax,ss) for rucaparib were calculated for each patient and averaged by actual dose received over time (AUCavg,ss and Cmax,avg,ss) using a previously developed population pharmacokinetic model.

RESULTS

Rucaparib exposure was dose-proportional and not associated with baseline patient weight. In the exposure-efficacy analyses (n = 121), AUCavg,ss was positively associated with independent radiology review-assessed RECIST response in the subgroup of patients with platinum-sensitive recurrent disease (n = 75, p = 0.017). In the exposure-safety analyses (n = 393, 40 mg once daily to 840 mg twice daily [BID] starting doses), most patients received a 600 mg BID rucaparib starting dose, with 27% and 21% receiving 1 or ≥2 dose reductions, respectively. Cmax,ss was significantly correlated with grade ≥2 serum creatinine increase, grade ≥3 alanine transaminase/aspartate transaminase increase, platelet decrease, fatigue/asthenia, and maximal hemoglobin decrease (p < 0.05).

CONCLUSION

The exposure-response analyses provide support for the approved starting dose of rucaparib 600 mg BID for maximum clinical benefit with subsequent dose modification only following the occurrence of a treatment-emergent adverse event in patients with BRCA-mutated recurrent ovarian carcinoma.

Slipping Through the Pores: Hypoalbuminemia and Albumin Loss During Hemodialysis

Hypoalbuminemia results when compensatory mechanisms are unable to keep pace with derangements in catabolism/loss and/or decreased synthesis of albumin. Across many disease states, including chronic kidney disease (CKD), hypoalbuminemia is a well-established, independent risk factor for adverse outcomes, including mortality. In the setting of CKD, reduced serum albumin concentrations are often a manifestation of protein-energy wasting, a state of metabolic and nutritional alterations resulting in reduced protein and energy stores. The progression of CKD to kidney failure and the initiation of maintenance hemodialysis (HD) further predisposes an already at-risk population toward hypoalbuminemia such that approximately 60% of HD patients have albumin concentrations <4.0 g/dl. Albumin loss into the dialysate through the dialyzer appears to be a potentially modifiable cause of hypoalbuminemia in some patients. A group of newer dialyzers for maintenance HD-sometimes termed protein-leaking or medium cut-off membranes-aim to improve clearance of middle molecules (vs high flux dialyzers) but are associated with increased albumin losses. In this article, we will examine the impact of dialyzer selection on albumin losses during conventional HD, including the clinical relevance of such losses on serum albumin levels. Data on the clinical relevance of albumin losses during dialysis and current gaps in the evidence base are also discussed.

Iron homeostasis is dysregulated, but the iron-hepcidin axis is functional, in chronic liver disease

BACKGROUND

Perturbations in iron homeostasis have been reported to be associated with irreversible liver injury in chronic liver disease (CLD). However, it is not clear whether liver dysfunction per se underlies such dysregulation or whether other factors also contribute to it. This study attempted to examine the issues involved.

METHODS

Patients diagnosed to have chronic liver disease (n = 63), who underwent a medically-indicated upper gastrointestinal endoscopy, were the subjects of this study. Patients with dyspepsia, who underwent such a procedure, and were found to have no endoscopic abnormalities, were used as control subjects (n = 49). Duodenal mucosal samples were obtained to study mRNA and protein levels of duodenal proteins involved in iron absorption. A blood sample was also obtained for estimation of hematological, iron-related, inflammatory and liver function-related parameters.

RESULTS

Patients with CLD had impaired liver function, anemia of inflammation and lower serum levels of hepcidin than control subjects. Gene (mRNA) expression levels of duodenal ferroportin and duodenal cytochrome b (proteins involved in iron absorption) were decreased, while that of divalent metal transporter-1 (DMT-1) was unchanged. Protein expression of DMT-1 was, however, decreased while that of ferroportin was unchanged. In the CLD group, serum hepcidin was predicted independently by serum ferritin and hemoglobin, but not by C-reactive protein (a marker of inflammation). CLD patients with serum ferritin greater than 300 μg/dL had significantly greater liver dysfunction (as indicated by significantly higher serum concentrations of bilirubin, AST and ALT, and MELD scores), higher serum concentrations of CRP and hepcidin, and higher ferroportin protein expression, than those with serum ferritin ≤ 300 μg/dL.

CONCLUSIONS

In patients with CLD, anemia of inflammation and low serum hepcidin levels were found to paradoxically co-exist. Expression of duodenal proteins involved in iron absorption were either decreased or unaltered in these patients. The hepcidin response to higher body iron levels and/or inflammation appeared to be functional in these patients, despite the presence of liver disease.

The Influence of Inflammation on Anemia in CKD Patients

Anemia is frequently observed in the course of chronic kidney disease (CKD) and it is associated with diminishing the quality of a patient’s life. It also enhances morbidity and mortality and hastens the CKD progression rate. Patients with CKD frequently suffer from a chronic inflammatory state which is related to a vast range of underlying factors. The results of studies have demonstrated that persistent inflammation may contribute to the variability in Hb levels and hyporesponsiveness to erythropoietin stimulating agents (ESA), which are frequently observed in CKD patients. The understanding of the impact of inflammatory cytokines on erythropoietin production and hepcidin synthesis will enable one to unravel the net of interactions of multiple factors involved in the pathogenesis of the anemia of chronic disease. It seems that anti-cytokine and anti-oxidative treatment strategies may be the future of pharmacological interventions aiming at the treatment of inflammation-associated hyporesponsiveness to ESA. The discovery of new therapeutic approaches towards the treatment of anemia in CKD patients has become highly awaited. The treatment of anemia with erythropoietin (EPO) was associated with great benefits for some patients but not all.

Efficacy and safety of a low monthly dose of intravenous iron sucrose in peritoneal dialysis patients

PURPOSE

Scientific data regarding intravenous iron supplementation in peritoneal dialysis (PD) patients are scarce. In attempting to administer the minimum monthly IV iron dose that could improve erythropoiesis, we wanted to assess the safety and efficacy of monthly maintenance intravenous administration of 100 mg iron sucrose in PD patients.

METHODS

In a 9-month prospective study, all clinically stable PD patients received intravenously 200 mg of iron sucrose as a loading dose, followed by monthly doses of 100 mg for five consecutive months. Levels of hemoglobin (Hb), ferritin, transferrin saturation (TSAT), reticulocyte hemoglobin content (CHr) and C-reactive protein (CRP) were measured before each administration and 3 months after the last iron infusion. Also, doses of concurrent erythropoietin administration were recorded.

RESULTS

Eighteen patients were eligible for the study. Mean levels of Hb and ferritin increased significantly (from 10.0 to 10.9 mg/dL, p = 0.01 and from 143 to 260 ng/mL, p = 0.005), as well as the increase in TSAT levels approached borderline significance (from 26.2 to 33.1%, p = 0.07). During the 6 months of iron administration, the erythropoietin dose was reduced in five patients and discontinued in one. During the 3 months following the last iron infusion, three of them again raised the erythropoietin dose to previous levels. None of the patients experienced any side effects related to IV iron administration.

CONCLUSIONS

A monthly maintenance intravenous dose of 100 mg iron sucrose may be a practical, effective, and safe in the short term, treatment of anemia in PD patients resulting in improved hemoglobin levels, iron indices, and erythropoietin response.

Restitution volumes at the end of dialysis sessions: A potential influencing factor on patients' haemoglobin levels?

AIM

To evaluate whether haemoglobin (Hb) levels are influenced by the restitution volume (RestVol) at the end of the dialysis session, independently of erythropoiesis-stimulating agents (ESA) and iron doses.

DESIGN

Over 12 months, 4,386 haemodialysis patients from 34 centres were enrolled in this observational descriptive study according to the checklist STrengthening the Reporting of Observational Studies in Epidemiology (STROBE).

METHOD

RestVol, Hb levels, ESA and iron doses of every patient were assessed on a monthly basis. To determine the ideal RestVol, the clinics were classified into three groups according to the restitution volumes at the end of the dialysis sessions.

RESULTS

Mean age was 69 ± 14 years, and 58.9% were men. The evaluation of 665,712 treatments revealed that RestVol of 380 ml seems to be the most efficient, since the clinics in this group managed to reduce ESA consumption with a negligible reduction in Hb levels.

Time-averaged hemoglobin values, not hemoglobin cycling, have an impact on outcomes in pediatric dialysis patients

BACKGROUND

During erythropoietin-stimulating agent (ESA) treatment, hemoglobin (Hb) levels usually fluctuate; this phenomenon is known as "Hb cycling (HC)." In this study, we aimed to evaluate the predictors of HC and its impact on left ventricular hypertrophy (LVH) as a patient-important outcome parameter in pediatric dialysis patients.

METHODS

Records of patients followed up in nine pediatric nephrology centers between 2008 and 2013 were reviewed. More than 1 g/dL decrease or increase in Hb level was considered as HC. Patients were divided into two groups according to 12-month Hb trajectory as rare cycling (RC) (≤ 3) and frequent cycling (FC) (> 3 fluctuation) as well as three groups based on T-A-Hb levels: < 10, 10-11, and > 11 g/dL.

RESULTS

Two hundred forty-five dialysis (160 peritoneal dialysis (PD) and 85 hemodialysis (HD)) patients aged 12.3 ± 5.1 (range 0.5-21) years were enrolled in this study. Fifty-two percent of the patients had RC, 45% had FC, and only 3% had no cycling. There were no differences between HC groups with respect to age, dialysis modality, having anemia, hospitalization rate, residual urine volume, and mortality. Although left ventricular mass index (LVMI) tended to be higher in RC than FC group (65 ± 37 vs 52 ± 23 g/m^2.7, p = 0.056), prevalence of LVH was not different between the groups (p = 0.920). In regression analysis, FC was not a risk factor for LVH, but low T-A Hb level (< 10 g/dL) was a significant risk for LVH (OR = 0.414, 95% CI 0.177-0.966, p = 0.04). The target Hb levels were more often achieved in PD patients, and the number of deaths was significantly lower in non-anemic patients (Hb level > 11 g/dL).

CONCLUSION

Hb cycling is common among dialysis patients. Severity of anemia rather than its cycling has more significant impact on the prevalence of LVH and on inflammatory state.

The anaemia control model: Does it help nephrologists in therapeutic decision-making in the management of anaemia?

INTRODUCTION

Anaemia is common in haemodialysis patients and treating it with erythropoiesis-stimulating agents (ESAs) is complex due to many factors.

OBJECTIVES

To assess the usefulness of the Anaemia Control Model (ACM) in the treatment of anaemia in haemodialysis.

METHODS

ACM is a software that predicts the optimal dose of darbepoetin and iron sucrose to achieve target haemoglobin (Hb) and ferritin levels, and makes prescription suggestions. Study conducted in dialysis clinics lasting 18months with two intervention phases (IPs) with ACM (IP1, n:213; IP2, n:218) separated by a control phase (CP, n:219). The primary outcome was the percentage of Hb in range and the median dose of ESAs, and the secondary outcomes were transfusion, hospitalisation and cardiovascular events. Clinical and patient analyses were performed. Hb variability was assessed by the standard deviation (SD) of the Hb. We also analysed the patients with most of the suggestions confirmed (ACM compliant group).

RESULTS

ACM increased the percentage of Hb in range: 80.9% in IP2, compared with 72.7% in the CP and reduced the intake of darbepoetin (IP1: 20 [70]; CP 30 [80] μg P=0.032) with less Hb fluctuation (0.91±0.49 in the CP to 0.82±0.37g/dl in IP2, P<0.05), improving in the ACM compliant group. The secondary outcomes decreased with the use of ACM.

CONCLUSIONS

ACM helps to obtain better anaemia results in haemodialysis patients, minimising the risks of treatment with ESAs and reducing costs.

Epoetin alfa resistance in hemodialysis patients with chronic kidney disease: a longitudinal study

Anemia is an inevitable complication of hemodialysis, and the primary cause is erythropoietin deficiency. After diagnosis, treatment begins with an erythropoiesis-stimulating agent (ESA). However, some patients remain anemic even after receiving this medication. This study aimed to investigate the factors associated with resistance to recombinant human erythropoietin therapy with epoetin alfa (αEPO). We performed a prospective, longitudinal study of hemodialysis patients receiving treatment with αEPO at our reference hospital from July 2015 to June 2016. Clinical data was collected, and the response to αEPO treatment was evaluated using the erythropoietin resistance index (ERI). The ERI was defined as the weekly weight-adjusted αEPO dose (U/kg per week)/hemoglobin level (g/dL). A longitudinal linear regression model was fitted with random effects to verify the relationships between clinical and laboratory data and ERI. We enrolled 99 patients (average age, 45.7 (±17.6) years; male, 51.5%; 86.8% with hypertension). The ERI showed a significant positive association with serum ferritin and C-reactive protein, percentage interdialytic weight gain, and continuous usage of angiotensin receptor blocker (ARB) hypertension medication. The ERI was negatively associated with serum iron and albumin, age, urea reduction ratio, and body mass index. Our findings indicate that resistance to αEPO was related to a low serum iron reserve, an inflammatory state, poor nutritional status, and continuous usage of ARBs.

Hepatic Proteins and Inflammatory Markers in Rheumatoid Arthritis Patients

BACKGROUND

Rheumatoid arthritis is an autoimmune inflammatory rheumatic disease that causes chronic synovial inflammation eventually leading to joint destruction and disability. The aim of this study was to determine the variations of hepatic proteins, myeloperoxidase, and iron in rheumatoid arthritis Tunisian patients and their implications in inflammation and in iron metabolism.

METHODS

Overall, 172 patients from the Rheumatology Department of the University Hospital "Farhat Hached", Sousse-Tunisia between 2011 and 2012, with rheumatoid arthritis (97.1% women, average age: 48±13 yr) and 147 healthy volunteers (70.1% women, average age: 46± 7 yr) were included in this study. Serum hepatic proteins (high-sensitive C-reactive protein, ceruloplasmin, albumin, transferrin, α-1-acid glycoprotein and haptoglobin) were assessed by immunoturbidimetry (COBAS INTEGRA 400, Roche) and ferritin was measured by a microparticulate immunoenzymatic technic (AxSYM, ABBOTT, Germany), Plasma myeloperoxidase was determined by Enzyme-Linked Immunosorbent Assay. Serum iron was measured according to a colorimetric method at 595 nm (CX9-BECKMANN Coulter-Fuller-Ton, CA).

RESULTS

Significantly higher levels of high-sensitive C-reactive protein, α-1-acid glycoprotein, Haptoglobin and myeloperoxidase in patients compared to controls (P<10^-3). Albumin and iron rates were significantly decreased in patients compared to healthy group (P=0.026 and P<10^-3, respectively). There were no differences between cases and controls for levels of ceruloplasmin, transferrin and ferritin (P=0.782, P=0.808, and P=0.175, respectively).

CONCLUSION

The high-sensitive C-reactive protein, α-1-acid glycoprotein, and haptoglobin increased in acute phase proteins in rheumatoid arthritis disease. The pro-inflammatory cytokines affect iron metabolism leading to the iron deficiency and rheumatoid anemia, which influenced Tf and ferritin levels.

Administration of a High-Dose Erythropoietin-Stimulating Agent in Hemodialysis Patients is Associated with Late Arteriovenous Fistula Failure

PURPOSE

Investigating the risk of vascular access failure is critical for maintenance hemodialysis (MHD) patients. Erythropoietin stimulating agents (ESA) typically used for anemia of chronic kidney disease (CKD) may also stimulate neointimal hyperplasia, which is the most important factor in late arteriovenous fistula (AVF) failure. The aim of this study was to investigate whether ESA treatment is associated with late AVF failure.

MATERIALS AND METHODS

The late AVF failure group comprised 51 patients who underwent percutaneous intervention or surgery for fistula revision after successful use for at least three months. There were 51 controls whose AVF had been patent for at least 24 months.

RESULTS

The mean time from the first cannulation to late loss of AVF patency was 8.4±4.2 months. The average weekly dose of ESA was significantly higher in patients with AVF failure (4782.2±2360.5 IU/mL/wk vs. 7161.8±2775.2 IU/mL/wk, p<0.001). The only independent predictor of late AVF failure in multivariate analysis was high average ESA dose (odds ratio=1.015, 95% confidence interval=1.002-1.028, p=0.022).

CONCLUSION

Patients with late AVF patency loss exhibit an association with a higher dose of ESA, although causality is unproven. Further study to elucidate potential mechanisms is warranted.

Oxidative stress during erythropoietin hyporesponsiveness anemia at end stage renal disease: Molecular and biochemical studies

Inflammation and oxidative stress are two faces of one coin in end stage renal disease patients (ESRD) on maintenance hemodialysis. Their interconnection induces anemia complicated with erythropoietin hyporesponsiveness. The biochemical bases behind the resistance to erythropoietin therapy with frequent hemoglobinemia, oxidative stress and iron status have not been fully understood. Here two equal groups (40 patients each) of responders and non-responders to recombinant human erythropoietin therapy (higher than 300 IU/kg/wk of epoetin) were investigated. Hematological and biochemical analyses of collected blood and serum samples were performed along with serum electrophoretic protein footprinting. The leukocytic DNA fragmentation was used to evaluate the degree of oxidative insult. The good responders showed lower erythrocyte malondialdehyde (E-MDA) level and less DNA fragmentation of circulating leukocytes than poor responders with elevated hemoglobin, albumin, A/G ratio, total iron, and ferritin levels. Contrariwise, lower erythrocyte superoxide dismutase (E-SOD) and catalase activities in EPO poor responder group were noticed. Neither other serum constituents nor electrophoretic protein pattern showed any difference between the two groups. There were higher levels of inflammatory markers, interleukin-6 (IL6) and C-reactive protein (CRP) in EPO poor responder than good responder. The negative correlations between Hb and both IL6 and CRP levels in the present data remotely indicate a positive correlation between inflammatory markers and severity of anemia. A direct correlation between Hb and antioxidant enzymes (E-SOD and catalase) was noticed, while inverse correlation with E-MDA was recorded. The study proved that oral supplementation of vitamin C to ESRD patients might mitigate the previously elevated serum MDA level in these patients.

Thresholds of iron markers for iron deficiency erythropoiesis-finding of the Japanese nationwide dialysis registry

Reportedly, serum ferritin levels are much lower in Japanese hemodialysis (HD) patients than their Western counterparts. Therefore, the cutoff values of ferritin and transferrin saturation (TSAT) for iron deficiency might differ from other countries. We conducted a cross-sectional observational study using the Japanese nationwide registry data. We enrolled 142,339 maintenance HD patients and assessed the association between these markers, hemoglobin (Hb), and erythropoiesis-stimulating agent (ESA) resistance index (ERI) utilizing restricted cubic spline analyses. Median ferritin and TSAT levels were 73 (IQR: 31–158) ng/ml and 23.7 (16.8–32.0)%, respectively. These lower ferritin ranges may possibly stem from a lower inflammatory state in Japanese patients, as shown in median CRP of 1.0 mg/l. An adjusted nonlinear association between Hb and TSAT showed that Hb levels drop with the decrease in TSAT below 20%, regardless of serum ferritin levels, suggesting the absolute iron deficiency cutoff as 20% for TSAT. In patients with TSAT >20%, the association between Hb and ferritin levels is nearly flat, whereas in patients with TSAT <20%, ferritin <50 ng/ml was associated with low Hb. In long-acting ESAs-users with TSAT >20%, U-shaped relationship was observed between ERI and ferritin with the bottom of ERI around 100 ng/ml of ferritin, possibly because high ferritin levels reflected an inflamed state leading to hyporesponsiveness to ESA. The patient subgroup with TSAT <20% and ferritin >100 ng/ml had significantly higher ERIs compared with the subgroup with TSAT >20% and ferritin <100 ng/ml, implying that TSAT, rather than ferritin, should be a primary iron marker predicting ESA response.

Factors precipitating erythropoiesis-stimulating agent responsiveness in a European haemodialysis cohort: case-crossover study

Purpose

Hyporesponsiveness to erythropoiesis‐stimulating agents (ESAs) is clinically and economically important in the treatment of anaemia in chronic kidney disease (CKD) patients. Previous studies focused on baseline predictors of ESA hyporesponsiveness, rather than factors associated with the transition to this state. Reversibility of ESA hyporesponsiveness has also not been studied previously.

Methods

Case‐crossover methodology was applied to a cohort of 6645 European CKD patients undergoing haemodialysis and prescribed ESAs. Ninety‐day ESA exposure periods were defined, haemoglobin (Hb) response was calculated using the last 30 days of one period and the first 30 days of the next, and periods were classified based on a median ESA dose (80.8 IU/kg/week) and a 10 g/dL Hb threshold. Clinical, dialysis and laboratory data from patients' first hyporesponsive ‘case’ period was compared with the preceding responsive ‘control’ period using conditional logistic regression. A similar approach was applied to hyporesponsiveness reversal.

Results

Of the patients, 672 experienced hyporesponsiveness periods with preceding responsive periods; 711 reversed to normality from hyporesponsiveness periods. Transition to hyporesponsiveness was associated with hospitalization, vascular access changes or worsening inflammation, with these factors accounting for over two‐thirds of transitions. Findings were largely insensitive to alternative ESA doses and Hb thresholds. Continued hospitalization, catheter insertion and uncontrolled secondary hyperparathyroidism were associated with a lack of regain of responsiveness.

Conclusions

Transition to hyporesponsiveness is linked to the development of conditions such as hospitalization events, vascular access issues or episodes of systemic inflammation. However, a third of hyporesponsive episodes remain unexplained. © 2015 The Authors. Pharmacoepidemiology and Drug Safety published by John Wiley & Sons Ltd.

Low baseline serum albumin as a predictor of anemia in chronic hemodialysis patients

BACKGROUND

Inflammatory process has a substantial contribution in the development of anemia in chronic hemodialysis patients. Low serum albumin in hemodialysis patients is considered a marker of inflammation. The present longitudinal study aimed to determine the relationship between low baseline serum albumin and future development of anemia.

METHODS

The population of this study consisted of all patients on standard maintenance hemodialysis for at least three months or longer. Patients were classified as high or low serum albumin level (≥ or < 3.9 gr/dl). All patients received the standard treatment of anemia. The main objective of this study was to compare the prevalence of anemia defined as hemoglobin levels < 11 gr/dl between the two study groups at the end of the study period.

RESULTS

A total of 82 patients (50% females) with mean±SD age of 55±16.8 years and mean dialysis duration of 5.2±4 years were followed-up for an average period of 10±1 (range, 8-11) months, however 48 patients with high serum albumin and 24 patients with low serum albumin group completed the study. At baseline, the two groups were similar regarding hemoglobin (9.8±1.2 vs 9.16±1.6 gr/dl, P=0.95) levels. At endpoint, prevalence of anemia in high albumin group was significantly lower than the low albumin group (50% versus 83.3% P=0.005).

CONCLUSION

The findings of this study indicate that low serum albumin in hemodialysis patients is a predictor of anemia indicating unresponsiveness to conventional treatment of anemia.

Body composition affects the response to erythropoiesis-stimulating agents in patients with chronic kidney disease in dialysis

BACKGROUND

The response to erythropoiesis-stimulating agents (ESA) in patients with chronic kidney disease (CKD) is variable. The body mass index (BMI) variations can modify the response to ESA. The objective was to assess the effect of body composition on the response to ESA in dialysis patients.

METHODS

This is an observational cross-sectional study. Prevalent hemodialysis and peritoneal dialysis (PD) patients were selected. In the same day, a single blood test, a body composition analysis using bioimpedance spectroscopy and anthropometric measurements were performed. We collected ESA doses. We analyzed erythropoietin resistance index (ERI). The ERI was calculated dividing the weekly weight-adjusted (kg) dose of ESA (IU) by the hemoglobin level (g/dL).

RESULTS

The study was comprised of 218 patients (58% men; age 65 (16) years old; 80% hemodialysis, 20% PD). There was an inverse correlation between ERI and BMI (p=0.01), fat tissue index (FTI) (p=0.01) and prealbumin (p=0.04). We found an independent association between higher ERI levels and lower FTI and prealbumin values.

CONCLUSION

Response to ESA is influenced by body composition. Fat tissue favors the body's response to ESA.

Pre-emptive replacement of water treatment components improves responsiveness to erythropoiesis-stimulating agents in maintenance haemodialysis patients: a quality improvement report

Hypo-responsiveness to erythropoiesis-stimulating agents (ESAs) has been associated with increased mortality. We examined the effect of water treatment component replacement on declining ESA responsiveness in the absence of chemical or microbiological standards failure. Pre-emptive renewal of the water treatment system supplying 802 standard-flux haemodialysis patients resulted in a significant rise in haemoglobin from (mean ± SD) 12.1 ± 1.2 to 12.3 ± 1.0 g/dl (p < 0.0001), accompanied by a significant decrease in prescribed dose of darbepoetin alfa from 47.9 ± 27.3 to 44.7 ± 27.6 μg/week (p < 0.0001). ESA responsiveness improved significantly from 0.060 ± 0.041 to 0.055 ± 0.040 μg/kg/g · dl(-1) (p < 0.0001) and the number of patients no longer requiring ESA therapy increased threefold. These benefits were derived in the absence of haemolysis or significant changes in water quality. Renewal of water system components should be conducted even in the absence of proven microbiological and chemical failure.

Hydroxocobalamin supplementation and erythropoisis stimulating agent hyporesponsiveness in haemodialysis patients

BACKGROUND

Long-term haemodialysis patients may be at risk of hydrosoluble vitamin deficiencies. This study aimed to test the hypothesis that in patients with serum B12 < 300 pmol/L, intramuscular hydroxocobalamin reduces erythropoietin requirements whilst maintaining haemoglobin concentrations (Hb).

METHODS

Study design was prospective, non-randomized, open label, with single group assignment. In 61 patients hydroxocobalamin 1000 μg was given weekly for 3 weeks and erythropoietin dose adjusted to target a Hb of 11-12 g/L. The primary outcome was the change in erythropoietin requirements at 2 years. Secondary outcomes included assessment of change in biochemical or clinical parameters.

RESULTS

The erythropoietin dose reduced from 11 000 ± 7000 (10 000) IU to 5000 ± 6000 (3000) IU per week (P < 0.001) with no change in Hb 116 ± 16 (117) g/L before and after 114 ± 15 (113) g/L (P = 0.488) hydroxocobalamin supplementation. Serum albumin rose from 35 ± 4 (35) g/L to 36 ± 4 (36) g/L (P = 0.03). A significant rise in red cell folate (RCF) and serum vitamin B12 levels was observed. Serum ferritin rose despite a reduction in intravenous iron usage and no significant change in c-reactive protein or transferrin saturation.

CONCLUSIONS

In HD patients with B12 < 300 pmol/L, following treatment with hydroxocobalamin there was reduced erythropoietin requirements, maintained Hb and a small but significant rise in the serum albumin. RCF may be low in haemodialysis patients with metabolic cobalamin deficiency and rises significantly after supplementation. Hydroxocobalamin supplementation may have the potential to reduce the cost of anaemia management.

Association of serum albumin concentration with mortality, morbidity, CD4 T-cell reconstitution among tanzanians initiating antiretroviral therapy

BACKGROUND

Prospective studies of serum albumin concentration measurement as a low-cost predictor of human immunodeficiency virus (HIV) disease progression are needed for individuals initiating antiretroviral therapy (ART) in resource-limited settings.

METHODS

Serum albumin concentration was measured at ART initiation for 2145 adults in Tanzania who were enrolled in a trial examining the effect of multivitamins on HIV disease progression. Participants were prospectively followed for mortality, morbidity, and anthropometric outcomes at monthly visits (median follow-up duration, 21.2 months). Proportional hazard models were used to analyze mortality, morbidity, and nutritional outcomes, while generalized estimating equations were used to analyze CD4(+) T-cell counts.

RESULTS

Individuals with hypoalbuminemia (defined as a serum albumin concentration of <35 g/L) at ART initiation had a hazard of death that was 4.52 times (95% confidence interval, 3.37-6.07; P < .001) that of individuals with serum albumin concentrations of ≥ 35 g/L, after multivariate adjustment. Hypoalbuminemia was also independently associated with the incidence of pulmonary tuberculosis (P < .001), severe anemia (P < .001), wasting (P = .002), and >10% weight loss (P = .012). Secondary analyses suggested that serum albumin concentrations of <38 g/L were associated with increased mortality and incident pulmonary tuberculosis. There was no association between serum albumin concentration and changes in CD4(+) T-cell counts (P = .121).

CONCLUSIONS

Serum albumin concentrations can identify adults initiating ART who are at high risk for mortality and selected morbidities. Future research is needed to identify and manage conditions that reduce the serum albumin concentration.

Predictors of haemoglobin levels and resistance to erythropoiesis-stimulating agents in patients treated with low-flux haemodialysis, haemofiltration and haemodiafiltration: results of a multicentre randomized and controlled trial

Background

Predictors of haemoglobin (Hb) levels and resistance to erythropoiesis-stimulating agents (ESAs) in dialysis patients have not yet been clearly defined. Some mainly uncontrolled studies suggest that online haemodiafiltration (HDF) may have a beneficial effect on Hb, whereas no data are available concerning online haemofiltration (HF). The objectives of this study were to evaluate the effects of convective treatments (CTs) on Hb levels and ESA resistance in comparison with low-flux haemodialysis (HD) and to evaluate the predictors of these outcomes.

Methods

Primary multivariate analysis was made of a pre-specified secondary outcome of a multicentre, open-label, randomized controlled study in which 146 chronic HD patients from 27 Italian centres were randomly assigned to HD (70 patients) or CTs: online pre-dilution HF (36 patients) or online pre-dilution HDF (40 patients).

Results

CTs did not affect Hb levels (P = 0.596) or ESA resistance (P = 0.984). Hb correlated with polycystic kidney disease (P = 0.001), C-reactive protein (P = 0.025), ferritin (P = 0.018), ESA dose (P < 0.001) and total cholesterol (P = 0.021). The participating centres were the main source of Hb variability (partial eta² 0.313, P < 0.001). ESA resistance directly correlated with serum ferritin (P = 0.030) and beta2 microglobulin (P = 0.065); participating centres were again a major source of variance (partial eta² 0.367, P < 0.001). Transferrin saturation did not predict either outcome variables (P = 0.277 and P = 0.170).

Conclusions

In comparison with low-flux HD, CTs did not significantly improve Hb levels or ESA resistance. The main sources of variability were participating centres, ESA dose and the underlying disease.

The relationship between the antioxidant system and anaemia in haemodialysis patients

Anaemia and oxidative stress are common features of chronic kidney disease, and both are associated with an increase in morbidity and mortality. There is growing evidence, from experimental and clinical studies, that oxidative stress may be implicated in the pathogenesis of anaemia. This study investigated the relationship between total antioxidant capacity, anaemia and serum albumin levels in 127 non-diabetic patients requiring haemodialysis. Total serum antioxidant capacity levels were determined and were found to be significantly correlated with levels of haemoglobin, haematocrit, serum albumin, serum total protein, malondialdehyde (a product of lipid peroxidation), potassium, phosphorus and alanine transaminase. There was also a significant correlation between serum albumin levels and haemoglobin and haematocrit levels. In conclusion, total antioxidant capacity was found to be inversely correlated with malondialdehyde levels and positively correlated with haemoglobin and haematocrit levels in non-diabetic patients requiring haemodialysis. Patients with high serum albumin concentrations and high total antioxidant capacity may also have high (i.e. normal) levels of haemoglobin.

Variant hemoglobin phenotypes may account for differential erythropoiesis-stimulating agent dosing in African-American hemodialysis patients

African-American patients with end-stage renal disease have historically lower hemoglobin concentrations and higher requirements of erythropoiesis-stimulating agent (ESA). While disparities in health-care access may partially explain these findings, the role of variant hemoglobin, such as sickle trait, has not been investigated. To clarify this, we evaluated 154 African-American patients receiving in-center hemodialysis with available hemoglobin phenotyping. The primary exposure was any abnormal hemoglobin variant and the primary outcome of higher-dose ESA was defined as a dose of 6500 or more units per treatment. Logistic regression assessed the association between variant hemoglobin and higher-dose ESA. Covariates included age, gender, diabetes, iron parameters, intravenous iron dose, parathyroid hormone, albumin, phosphorus, body mass index, vascular access type, hospitalization/missed treatments, smoking status, alcohol abuse, and gastrointestinal bleeding. Of 33 patients with variant hemoglobin, 24 had HbAS and 9 had HbAC. Univariate odds of higher-dose ESA among those with hemoglobin variants were twice that of those with the normal HbAA phenotype (odds ratio 2.05). In multivariate models, the likelihood of higher-dose ESA had an odds ratio of 3.31 and the nature of this relationship did not change in Poisson regression or sensitivity analyses. Hence, our findings may explain, in part, the difference in ESA dosing between Caucasians and African-Americans with end-stage renal disease but await further study.

Association between the malnutrition-inflammation score and post-transplant anaemia

BACKGROUND

Post-transplant anaemia (PTA) is common and is associated with adverse consequences. The protein-energy wasting (PEW) syndrome is associated with erythropoietin resistance in patients on maintenance dialysis. We assessed the association between PEW and PTA in a large prevalent cohort of stable kidney-transplanted patients.

METHODS

Data from 942 prevalent kidney-transplanted patients were analysed. Socio-demographic parameters, laboratory results, transplantation-related data and medication were obtained from the charts. Biomarkers reflecting nutritional status and inflammation [serum leptin, albumin, interleukin-6 (IL-6), tumour necrosis factor-α (TNF-α) and C-reactive protein] were measured. Anthropometric measures and the malnutrition-inflammation score (MIS) were also tabulated. Anaemia was defined according to the guidelines of the American Society of Transplantation.

RESULTS

Mean age was 51 ± 13 years, 57% were males and 22% had diabetes. The prevalence of PTA was 33%. The haemoglobin (Hb) level significantly and negatively correlated with the MIS (rho = - 0.316), marginally with serum TNF-α (rho = - 0.079) and serum IL-6 (rho = - 0.075) and positively with serum transferrin (r = 0.298), serum albumin (r = 0.274), abdominal circumference (r = 0.254) and serum leptin (rho = - 0.152), P < 0.05 for all. In a multivariable linear regression model, MIS was independently associated with Hb (beta = - 0.118, P = 0.004) in patients with estimated glomerular filtration rate (eGFR) lower than or equal to 60 mL/min/1.73 m(2), but not in patients with higher eGFR.

CONCLUSIONS

The MIS is independently associated with PTA in the kidney-transplanted population with eGFR lower than or equal to 60 mL/min/1.73 m(2).

Role of residual renal function in phosphate control and anemia management in chronic hemodialysis patients

BACKGROUND AND OBJECTIVES

There is increasing awareness that residual renal function (RRF) has beneficial effects in hemodialysis (HD) patients. The aim of this study was to investigate the role of RRF, expressed as GFR, in phosphate and anemia management in chronic HD patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Baseline data of 552 consecutive patients from the Convective Transport Study (CONTRAST) were analyzed. Patients with a urinary output≥100 ml/24 h (n=295) were categorized in tertiles on the basis of degree of GFR and compared with anuric patients (i.e., urinary output<100 ml/24 h, n=274). Relations between GFR and serum phosphate and erythropoiesis-stimulating agent (ESA) index (weekly ESA dose per kg body weight divided by hematocrit) were analyzed with multivariable regression models.

RESULTS

Phosphate levels were between 3.5 and 5.5 mg/dl in 68% of patients in the upper tertile (GFR>4.13 ml/min per 1.73 m2), as compared with 46% in anuric patients despite lower prescription of phosphate-binding agents. Mean hemoglobin levels were 11.9±1.2 g/dl with no differences between the GFR categories. The ESA index was 31% lower in patients in the upper tertile as compared with anuric patients. After adjustments for patient characteristics, patients in the upper tertile had significantly lower serum phosphate levels and ESA index as compared with anuric patients.

CONCLUSIONS

This study suggests a strong relation between RRF and improved phosphate and anemia control in HD patients. Efforts to preserve RRF in HD patients could improve outcomes and should be encouraged.

Novel serum biomarkers for erythropoietin use in humans: a proteomic approach

Erythropoietin (Epo) is produced primarily in the kidneys upon low blood oxygen availability and stimulates erythropoiesis in the bone marrow. Recombinant human Epo (rHuEpo), a drug developed to increase arterial oxygen content in patients, is also illicitly used by athletes to improve their endurance performance. Therefore, a robust and sensitive test to detect its abuse is needed. The aim of the present study was to investigate potential human serum biomarkers of Epo abuse employing a proteomic approach. Eight healthy male subjects were injected subcutaneously with rHuEpo (5,000 IU) every second day for a 16-day period. Serum was collected before starting the treatment regime and again at days 8 and 16 during the treatment period. Samples were homogenized and proteins separated by two-dimensional gel electrophoresis (2DE). Spots that changed significantly in response to rHuEpo treatment were identified by mass spectrometry. Both the number of reticulocytes and erythrocytes increased throughout the study, leading to a significant increase in hematocrit and hemoglobin content. In addition, transferrin levels increased but the percentage of iron bound to transferrin and ferritin levels decreased. Out of 97 serum proteins, seven were found to decrease significantly at day 16 compared with pre-Epo administration, and were identified as four isoforms of haptoglobin, two isoforms of transferrin, and a mixture of hemopexin and albumin. In support, total serum haptoglobin levels were found to be significantly decreased at both days 8 and 16. Thus a 2DE proteomic approach for discovery of novel markers of Epo action appears feasible.

Use of 12x/month haemoglobin monitoring with a computer algorithm reduces haemoglobin variability

BACKGROUND

Haemoglobin variability may be associated with increased death. Frequent haemoglobin monitoring may allow earlier detection of trends in haemoglobin slopes, alerting staff to intercurrent events. The more frequent haemoglobin values may provide early evidence of response to erythropoietin (EPO) doses, and allow more appropriate anaemia management. Our objective is to assess whether frequent haemoglobin monitoring data (12x/month) using a computer algorithm (AMIE, Leeds, UK) will reduce haemoglobin variability compared with 1x/month monitoring.

METHODS

We performed an observational case-control study of 44 unselected patients, comprising one dialysis facility measuring Crit-Line haemoglobin, lab haemoglobin, standard deviation of residuals as surrogate of haemoglobin variability and EPO dosing.

RESULTS

Haemoglobin variability and 'percent in target haemoglobin range' significantly improved with 12x/month haemoglobin results using a computer algorithm. There was also a non-significant trend toward for lower EPO doses.

CONCLUSION

Use of a computer algorithm to analyse 12x/month haemoglobin values provides early evidence of haemoglobin trends and allows more appropriate anaemia management, with decreased haemoglobin variability, lower EPO doses and more patients achieving target haemoglobin.

Secondary hyperparathyroidism and anemia in children treated by hemodialysis

BACKGROUND

Many patients treated using hemodialysis remain anemic despite exogenous erythropoietin therapy, suggesting that the anemia experienced by these patients is multifactorial in cause. Iron deficiency, infection, inflammation, and malnutrition have been implicated in this process. Additionally, secondary hyperparathyroidism has been associated with anemia in adults, but few data exist about this topic in children.

STUDY DESIGN

Cross-sectional retrospective.

SETTING & PARTICIPANTS

Children treated in hemodialysis centers (N = 588) within the Centers for Medicare & Medicaid Services' 2002 Clinical Performance Measures Project.

PREDICTOR

Intact parathyroid hormone (iPTH) levels assessed in October, November, and December 2001 and categorized as quintiles.

OUTCOMES & MEASUREMENTS

Achievement of serum hemoglobin level > or = 11 g/dL was assessed using Poisson regression adjusting for sex, age, race, dialysis vintage, vascular access type, single-pool Kt/V, serum albumin level, normalized protein catabolic rate, calcium-phosphorus product, and erythropoietin alfa dose.

RESULTS

Using the second quintile (iPTH, 103-224 pg/mL) as the reference quintile, there was no association between iPTH quintile and achievement of the hemoglobin goal: quintile 1 prevalence ratio, 1.0 (95% CI, 0.9-1.2); quintile 3, 0.95 (95% CI, 0.8-1.1); quintile 4, 0.99 (95% CI, 0.8-1.2); and quintile 5, 0.97 (95% CI, 0.8-1.1). Only serum albumin level >/= 3.5 g/dL (bromocresol green assay method) or > or = 3.2 g/dL (bromocresol purple assay method) was significantly associated with meeting the hemoglobin goal: 1.4 (95% CI, 1.2-1.6).

LIMITATIONS

The simultaneous collection of iPTH and hemoglobin limits causal inference. Iron stores and iron therapy are potential confounders not accounted for in this study.

CONCLUSIONS

In the largest study of this topic in children, no association was found between iPTH level and achievement of a hemoglobin level > or = 11 g/dL. Serum albumin level was associated strongly with achievement of the hemoglobin goal.

Iron, inflammation, dialysis adequacy, nutritional status, and hyperparathyroidism modify erythropoietic response

BACKGROUND AND OBJECTIVES

The erythropoietic response in hemodialysis patients depends on several physiologic factors. Most epidemiologic studies include the effect of these factors by representing them as confounders. This study tested the hypothesis that iron stores, inflammation, dialysis adequacy, nutritional status, and hyperparathyroidism act as nonlinear effect modifiers of the erythropoietic response and quantified the magnitude of those effects over clinically relevant ranges.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The following retrospective data from 209 hemodialysis patients receiving Epoetin alfa (Epo) were collected: monthly: predialysis hemoglobin (Hgb), transferrin saturation, serum albumin, dialysis adequacy (Kt/V); quarterly: predialysis serum ferritin and intact parathyroid hormone over a period of 13 to 69 months. The study analyzed the dynamic relationship between hemoglobin and Epo, considering nonlinear effect modification by ferritin, transferrin saturation, Kt/V, albumin, and parathyroid hormone individually.

RESULTS

Maximum Hgb response to Epo was achieved for serum ferritin between 350 and 500 ng/ml, transferrin saturation greater than 30%, Kt/V greater than 1.4, and albumin greater than 3.8 g/dl. Hgb sensitivity to Epo decreases by about 30% as parathyroid hormone increases from 0 through 1000 pg/ml.

CONCLUSIONS

Serum ferritin, transferrin saturation, Kt/V, serum albumin, and intact parathyroid hormone are markers of nonlinear effect modification of the erythropoietic response in hemodialysis patients.

Effects of peridialytic oral supplements on nutritional status and quality of life in chronic hemodialysis patients

OBJECTIVE

Our objective was to determine the effects of peridialytic oral supplements on nutritional markers and quality of life (QOL) in patients receiving maintenance hemodialysis.

DESIGN

This trial was open, prospective, nonrandomized, and comparative.

SETTING

This study was performed at an outpatient hemodialysis unit in a teaching hospital.

PATIENTS

This study included 88 adults with chronic kidney disease at stage 5.

INTERVENTION

This study involved directly observed nutrition therapy with >or=1 can of enteral nutrition (Nepro) with each hemodialysis session thrice weekly for 3 months, or standard care.

MAIN OUTCOME MEASURE

Changes in biochemical markers of nutritional status and QOL, as measured by the Kidney Disease Quality of Life-Short Form, were determined.

RESULTS

Peridialytic oral nutrition resulted in a significant difference between the nutrition and comparison groups in serum albumin change over time (P = .03; repeated-measures analysis of variance with covariates). Mean (+/-SD) serum albumin concentration did not differ between baseline and month 3 in the nutrition group (3.68 +/- 0.33 g/dL vs. 3.75 +/- 0.40 g/dL; P = .12), but in the comparison group, serum albumin levels declined significantly (3.93 +/- 0.34 g/dL at baseline versus 3.81 +/- 0.37 g/dL at month 3; P = .04). The "role-physical" domain score of the Kidney Disease Quality of Life-Short Form significantly changed over time in the nutrition group versus the comparison group (P = .02; repeated-measures analysis of variance with covariates). Nepro was well-tolerated, and greater than 80% of the prescribed therapy was consumed.

CONCLUSION

Oral nutrition, as part of structured, directly observed peridialytic therapy in chronic hemodialysis patients, was well-accepted, and resulted in the maintenance of serum albumin levels and QOL with respect to impact of physical health on daily activities. These findings need to be confirmed in a randomized, controlled trial.

Factors that condition the response to erythropoietin in patients on hemodialysis and their relation to mortality

The response to erythropoietin-stimulating agents (ESA) can vary among different patients and according to the different circumstances over time within a given individual. The aim of this study was to analyze the factors that can modify the response to epoetin in patients on hemodialysis (HD) and its influence on early mortality. Prospective and observational study including 1710 patients from 119 HD units in Spain with a follow-up of 12 months. To evaluate the dose-response effect of EPO therapy, we used the erythropoietin resistance index (ERI), calculated as the weekly weight-adjusted dose of EPO divided by the hemoglobin level. Patients were stratified in three groups according to ERI: group A, ERI <5; group B, ERI=5-15; group C, ERI>15 U/kg/week/g per 100 ml. Mean ERI for the entire group was 10.2+/-7.3 U/kg/week/g per 100 ml. ERI was directly related with incident comorbidity (Charlson Index), age, female gender and low body mass index with no relationship with etiology of chronic kidney disease. Patients with antecedents of heart failure, acute infection or malignant neoplasm had significantly higher ERI than those without. Transferrin saturation index, but not serum ferritin, was inversely related with ERI. Serum levels of albumin and cholesterol were related with lower ERI, but no relation was found with normalized protein catabolic rate. Patients with a permanent catheter for HD had significant higher values of ERI than those with native fistula (P=0.012). One year survival in all three groups of patients according to ERI was 0.916 in group A, 0.877 in group B and 0.788 in group C (log-rank=20.7, P<0.001). The resistance to ESA is directly related with incident comorbidity in patients on hemodialysis and it can be interpreted as a useful marker of early mortality.

Hyporesponsiveness to erythropoietin: causes and management

In patients with chronic kidney disease, erythropoietin resistance is common, costly, and has implications beyond the management of anemia because the presence of erythropoietin resistance portends mortal outcomes. Exploring the provenance of erythropoietin resistance may be facilitated by the consideration of the pathogenetic triad of iron-restricted erythropoiesis, inflammation, and bone marrow suppression. Challenging to diagnose because of difficulty in interpreting tests of iron deficiency, iron-restricted erythropoiesis should be considered in patients who require high doses of erythropoietin, have low transferrin saturation (eg, <20%-25%), and do not have very high ferritin (eg, <1,200 ng/mL); a therapeutic trial of intravenous iron may be worthwhile. Aluminum intoxication is a rare cause of iron-restricted erythropoiesis that may manifest as microcytic hypochromic anemia. A decrease in serum albumin concentration may signal the presence of inflammation, which may be manifest (such as because of a recent illness or infection) or occult; the latter include clotted synthetic angioaccess, failed renal allograft, dialysis catheter, periodontal disease, underlying malignancy, or uremia per se. Marrow hyporesponsiveness may be improved by increasing the delivered dialysis dose, using ultrapure dialysate, maintaining adequate vitamin B12 and folate stores, or by treating hyperparathyroidism. In summary, improving the outcomes of erythropoietin-resistant patients will require complete patient assessment that goes beyond considerations of iron and erythropoietin dose alone. Given that erythropoietin dose is associated with mortality, mitigating erythropoietin resistance has the potential to improve patient outcomes.

Hemoglobin variability and hyporesponsiveness: much ado about something or nothing?

Hemoglobin (Hb) variability is considered a discrete clinical entity that when present may presage poor clinical outcomes. However, Hb variability is an intrinsic property of biological systems and is present in all patients, those with and without the anemia of chronic kidney disease. Taken together, variability actually represents the integration of multiple influences at multiple levels in the life of a red cell, namely the summation of positive and negative influences on erythropoiesis. Thus, Hb variability may be interpreted as a mathematic function of time and is the result of a host of influences including definition of the normal Hb range, native erythron responsiveness/hyporesponsiveness, temporal changes in endogenous and exogenous erythropoiesis-stimulating agent (ESA) levels, the algorithms used to dose ESAs and their duration of action, the presence of biologically available iron, red cell turnover, and recyclable and non-recyclable blood loss and gain. When viewed within this construct of matrixed determinants, the source of hemoglobin variability is more readily identified. When variability is present but the etiology is not easily discerned, erythropoietic hyporesponsiveness must be considered and evaluated. Finally, integration of all of these concepts is possible within the context of an anemia management protocol.

Inflammation and its impact on anaemia in chronic kidney disease: from haemoglobin variability to hyporesponsiveness

The availability of erythropoiesis-stimulating agents (ESAs) has revolutionized the treatment of anaemia in patients with chronic kidney disease. However, maintaining patients at haemoglobin (Hb) levels that are both safe and provide maximal benefit is a continuing challenge in the field. Based on emerging data on the potential risks of Hb treatment targets >13 g/dL, treatment targets have recently been lowered. In the latest revision (March 2008) of the European product labelling for the ESA class of drugs, the target treatment range was lowered to 10–12 g/dL. Fluctuation of Hb levels or ‘Hb variability’ during treatment with ESAs is a well-documented phenomenon. Hb levels that are either too high or too low may have an adverse effect on patient outcomes; thus, it is important to understand the causes of Hb variability in order to achieve optimal treatment. Several factors are believed to contribute to variation in the Hb level, including patient comorbidities and intercurrent events. Inflammation is also an important factor associated with Hb variability, and the consequences of persistent inflammatory activity are far-reaching in affected patients. This review addresses the complex role of inflammation in chronic kidney disease, as evidenced by the apparent state of deranged inflammatory markers. The mechanisms by which inflammatory cytokines may affect the response to ESAs, the development of anaemia and poor treatment outcomes are also examined. In addition, various options for intervention to enhance the response to ESAs in haemodialysis patients with inflammation are considered.

Serum albumin level and risk for mortality and hospitalization in adolescents on hemodialysis

BACKGROUND AND OBJECTIVES

National Kidney Foundation Dialysis Outcomes Quality Initiative practice guidelines recommend serum albumin > or = 4.0 g/dl for adults who are on hemodialysis. There is no established pediatric target for albumin and little evidence to support use of adult guidelines. This study examined the association between albumin and risk for death and hospitalization in adolescents who are on hemodialysis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This retrospective cohort study linked data on patients aged 12 to 18 yr in 1999 and 2000 from the Centers for Medicare and Medicaid Services' End Stage Renal Disease Clinical Performance Measures Project with 4-yr hospitalization and mortality records in the United States Renal Data System. Albumin was categorized as < 3.5/3.2, > or = 3.5/3.2 and < 4.0/3.7, and > or = 4.0/3.7 g/dl.

RESULTS

Of 675 adolescents, 557 were hospitalized and 50 died. Albumin > or = 4.0/3.7 g/dl was associated with male gender, Hispanic ethnicity, and higher hemoglobin level. Those with albumin > or = 4.0/3.7 g/dl had fewer deaths per 100 patient-years and fewer hospitalizations per time at risk. In multivariate analysis, patients with albumin > or = 4.0/3.7 g/dl had 57% decreased risk for death. Poisson regression showed progressive decrease in hospitalization risk as albumin level increased; however, confidence intervals were similar between albumin > or = 4.0/3.7 g/dl and albumin > or = 3.5/3.2 and < 4.0/3.7 g/dl.

CONCLUSIONS

This study demonstrates decreased mortality and hospitalization risk with albumin > or = 3.5/3.2 g/dl and suggests that adolescent hemodialysis patients who are able to achieve serum albumin > or = 4.0/3.7 g/dl may have the lowest mortality risk.