Hemoglobin variability and mortality in ESRD

Effects of the Omicron variant of coronavirus disease 2019 on anaemia treatment for patients undergoing peritoneal dialysis

AIM

Patients undergoing dialysis are at high risk for coronavirus disease 2019 (COVID-19). Haemoglobin (Hb) levels may be changed in patients infected with the Omicron variant of COVID-19 who are undergoing peritoneal dialysis (PD). Therefore, we aimed to explore the effect of anti-anaemia treatment on such patients.

METHODS

This study enrolled patients undergoing PD who were infected with the Omicron variant of COVID-19 at our centre between November 2022 and February 2023. We retrospectively analysed changes in Hb levels and explored the effectiveness of roxadustat and recombinant human erythropoietin (rhEPO) for patients infected with the Omicron variant of COVID-19.

RESULTS

Among 125 enrolled patients, 83 (66.4%) were infected with the Omicron variant and 75 (90.4%) patients mainly experienced mild or moderate disease. During infection, C-reactive protein (CRP) levels were higher than those before infection (p < .001). Additionally, their CRP levels were negatively correlated with Hb levels (p = .002). However, Hb levels were decreased 1 month after infection (109.61 ± 10.64 g/L vs. 115.69 ± 12.04 g/L; p < .001). The roxadustat treatment group did not exhibit significantly decreased Hb levels 1 month after infection (114.57 ± 14.11 vs. 117.51 ± 10.74 g/L; p = .225). Conversely, the rhEPO treatment group experienced a mild decrease in Hb levels (108.69 ± 11.20 vs. 115.03 ± 12.23 g/L; p = .001). Ferritin levels increased in both groups during infection (p = .495). Two months after infection, ferritin levels (median, 205.0 ng/mL) were significantly decreased compared with during infection (median, 377.4 ng/mL) (p < .001) in the roxadustat treatment group.

CONCLUSION

Roxadustat was effective than rhEPO for treating anaemia in patients undergoing PD who were infected with the Omicron variant of COVID-19.

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.

Mechanisms of hemoglobin cycling in anemia patients treated with erythropoiesis-stimulating agents

Patients with renal anemia are frequently treated with erythropoiesis-stimulating agents (ESAs), which are dynamically dosed in order to stabilize blood hemoglobin levels within a specified target range. During typical ESA treatments, a fraction of patients experience hemoglobin 'cycling' periods during which hemoglobin levels periodically over- and undershoot the target range. Here we report a specific mechanism of hemoglobin cycling, whereby cycles emerge from the patient's delayed physiological response to ESAs and concurrent ESA dose adjustments. We introduce a minimal theoretical model that can explain dynamic hallmarks of observed hemoglobin cycling events in clinical time series and elucidates how physiological factors (such as red blood cell lifespan and ESA responsiveness) and treatment-related factors (such as dosing schemes) affect cycling. These results show that in general, hemoglobin cycling cannot be attributed to patient physiology or ESA treatment alone but emerges through an interplay of both, with consequences for the design of ESA treatment strategies.

Anemia biomarkers and mortality in hemodialysis patients with or without diabetes: A 10-year follow-up study

BACKGROUND

Many studies have assessed the association between anemia and mortality in hemodialysis but few compared patients with and without diabetes. Our study aims to investigate the impact of hemoglobin and iron parameters on mortality in hemodialysis patients with or without diabetes.

METHODS

This is a two-center retrospective study that included all adult patients who started hemodialysis between February 2012 and February 2020, followed until January 2021. Averages of hemoglobin, ferritin and transferrin saturation of entire follow-up were recorded. Kaplan Meier survival, log rank test and cox regression analyses were performed to assess the association between anemia biomarkers and mortality.

RESULTS

A total of 214 patients were included. Mean age was 67.98 ±12.41 years, mean hemoglobin was 10.92 ±0.75 g/dL, mean ferritin was 504.43 ± 221.42 ng/mL and mean transferrin saturation was 26.23 ±7.77%. Log rank test showed an association between hemoglobin ≥11 g/dL and better survival in patients without diabetes (P = 0.028). Based on cox regression analysis, hemoglobin was associated with all-cause mortality in all patients (HR = 0.66; CI:0.49,0.89; P = 0.007). When comparing patients with and without diabetes, this association remained significant only in patients without diabetes (HR = 0.53; CI:0.37,0.77; P<0.001). Based on different multivariate models, hemoglobin, ferritin and age were independent factors associated with mortality in patients without diabetes.

CONCLUSIONS

This study showed that hemoglobin ≥11 g/dL is associated with better survival in hemodialysis patients without diabetes but not in those with diabetes. These differences need to be further explored in other countries and settings. An individualization of the hemoglobin target level might be necessary to improve patients' outcomes.

Variability in serum creatinine is associated with waitlist and post-liver transplant mortality in patients with cirrhosis

BACKGROUND AND AIMS

Kidney function in patients with cirrhosis is dynamic. After controlling for the presence of chronic kidney disease (CKD) and acute kidney injury (AKI), we investigated the impact of variation in clinical function on pre-liver transplantation (LT) and post-LT outcomes.

APPROACH AND RESULTS

We included adults listed for LT from 2011 through 2018. We excluded those with any exceptions, those on hemodialysis at listing, and those with fewer than three clinical updates in the United Network for Organ Sharing database. Our primary exposure was the serum creatinine coefficient of variation (sCr CoV). Logistic regression determined the associations between our exposures and higher sCr CoV. Competing risk regression determined the associations between our exposures and waitlist mortality, accounting for LT as a competing risk. Cox regression determined the associations between our exposures and either listing for kidney transplant or death. We divided our cohort into tertiles of sCr CoV: low variability, 8.8% (interquartile range [IQR], 6.6%-10.8%); intermediate variability, 17.4% (IQR, 14.8%-20.4%); high variability, 36.8% (IQR, 29.5%-48.8%). We demonstrate that women, those with CKD, and those with advanced liver disease were more likely to have a greater sCr CoV. Compared to those with low variability, those with high variability had significantly higher waitlist mortality (34.7% vs. 19.6% vs. 11.7%, p < 0.001). We highlight that the sCr CoV was associated with higher waitlist and post-LT mortality-an association independent of baseline sCr, the degree of underlying liver disease, the presence of AKI, or the presence of CKD.

CONCLUSION

This study informs the long-term impact of the variation in kidney function we all see in clinical practice. These data highlight that all fluctuations in sCr are associated with worse pre-LT and post-LT outcomes.

High hemoglobin fluctuation was a protective factor for cardiovascular-related death in peritoneal dialysis (PD) patients: A retrospective analysis of 232 patients with PD

Objectives

This study aimed to investigate the effect of hemoglobin (Hb) fluctuation after dialysis on the prognosis of cardiovascular‐related and all‐cause deaths in peritoneal dialysis (PD).

Methods

According to the Hb fluctuation, patients were divided into low fluctuation group, moderate fluctuation group, and high fluctuation group, and then, the effects of Hb fluctuation after dialysis on the prognosis of cardiovascular‐related and all‐cause death in PD were analyzed by regression analysis.

Results

A total of 232 patients were selected in this study. Compared with the low Hb fluctuation group, the moderate and high fluctuation groups had lower body mass index (BMI), estimated glomerular filtration rate (eGFR), and baseline Hb, and the moderate fluctuation group had less erythropoietin (EPO) and dialysis dose. Compared with survivors, patients with cardiovascular‐related and all‐cause deaths had lower mean Hb and Hb fluctuation (all p < 0.05). Cox regression analysis showed that before and after adjusting for confounding factors, Hb fluctuation was still independently correlated with cardiovascular prognosis, and higher Hb fluctuation was still a protective factor for cardiovascular‐related death in the Hb‐substandard group, but there was no significant correlation between Hb fluctuation and all‐cause death. Multivariate linear regression analysis revealed that Hb fluctuation was positively correlated with Kt/V and EPO dosage, but negatively correlated with the baseline Hb.

Conclusion

High Hb fluctuation was a protective factor for cardiovascular‐related death in PD with substandard Hb. Compared with Hb fluctuation, correction of anemia timely and making Hb reaches the standard level had a greater impact on reducing cardiovascular‐related death in PD.

Assessing mechanical catheter dysfunction in automated tidal peritoneal dialysis using cycler software: a case control, proof-of-concept study

New recommendations on evaluation of peritoneal membrane function suggest ruling out catheter dysfunction when evaluating patients with low ultrafiltration capacity. We introduce the use of a combination of parameters obtained from the cycler software PD Link with HomeChoicePro (Baxter International Inc., Illinois, United States) cyclers for predicting catheter dysfunction in automated peritoneal dialysis patients (APD). Out of 117 patients treated at the Medical University of Vienna between 2015 and 2021, we retrospectively identified all patients with verified catheter dysfunction (n = 14) and compared them to controls without clinical evidence of mechanical catheter problems and a recent X-ray confirming PD catheter tip in the rectovesical/rectouterine space (n = 19). All patients had a coiled single-cuff PD catheter, performed tidal PD, and received neutral pH bicarbonate/lactate-buffered PD fluids with low-glucose degradation products on APD. Icodextrin-containing PD fluids were used for daytime dwells. We retrieved cycler data for seven days each and tested parameters' predictive capability of catheter dysfunction. Total number of alarms/week > 7 as single predictive parameter of catheter dislocation identified 85.7% (sensitivity) of patients with dislocated catheter, whereas 31.6% (1-specificity) of control patients were false positive. A combination of parameters (number of alarms/week > 7, total drain time > 22 min, ultrafiltration of last fill < 150 mL) where at least two of three parameters appeared identified the same proportion of patients with catheter dislocation, but was more accurate in identifying controls (21.1% false positive). In contrast to yearly PET measurements, an easily applicable combination of daily cycler readout parameters, also available in new APD systems connected to remote monitoring platforms shows potential for diagnosis of catheter dysfunction during routine follow-up.

Patterns of chronic and transient hyperkalaemia and clinically important outcomes in patients with chronic kidney disease

Background

Whether hyperkalaemia in CKD is chronic or transient, and whether this has different outcome implications, is not known.

Methods

This was an observational study of adults with CKD G3–5 from Stockholm, Sweden 2006–11. We examined individual trajectories of potassium from all measurements obtained through routine outpatient care. For each month of follow-up, we created a rolling assessment of the proportion of time in which potassium was abnormal during the previous 12 months. We defined patterns of hyperkalaemia as transient (≤50% of time during the previous year with potassium >5.0 mmol/L) and chronic (>50% of time with potassium >5.0 mmol/L), and examined whether previous hyperkalaemia pattern offers additional predictive value beyond that provided by the most recent (current) potassium value.

Results

We included 36 511 participants (56% women) with CKD G3–5 and median estimated glomerular filtration rate 46 mL/min/1.73 m². Transient and chronic hyperkalaemia, respectively, were observed in 15% and 4% of patients with CKD G3a, and in 50% and 17% of patients with CKD G5. In fully adjusted models, transient (hazard ratio 1.36, 95% confidence interval 1.29–1.46) or chronic (1.16, 1.04–1.32) hyperkalaemia patterns, but not current hyperkalaemia, were associated with major adverse cardiovascular events (MACE), compared with normokalaemia. Transient hyperkalaemia (1.43, 1.35–1.52) and current potassium values, but not chronic hyperkalaemia, were associated with the risk of death.

Conclusions

Between 4% and 17% of patients with CKD G3–5 develop chronic hyperkalaemia. In general, hyperkalaemia predicted MACE and death; however, the lack of effect of current potassium on MACE when adjusted for the previous pattern, and the stronger effects on death than on MACE, lead us to question whether hyperkalaemia is causal in these relationships.

Prediction of Mortality in Hemodialysis Patients Using Moving Multivariate Distance

There is an increasingly widespread use of biomarkers in network physiology to evaluate an organism’s physiological state. A recent study showed that albumin variability increases before death in chronic hemodialysis patients. We hypothesized that a multivariate statistical approach would better allow us to capture signals of impending physiological collapse/death. We proposed a Moving Multivariate Distance (MMD), based on the Mahalanobis distance, to quantify the variability of the multivariate biomarker profile as a whole from one visit to the next. Biomarker profiles from a visit were used as the reference to calculate MMD at the subsequent visit. We selected 16 biomarkers (of which 11 are measured every 2 weeks) from blood samples of 763 chronic kidney disease patients hemodialyzed at the CHUS hospital in Quebec, who visited the hospital regularly (∼every 2 weeks) to perform routine blood tests. MMD tended to increase markedly preceding death, indicating an increasing intraindividual multivariate variability presaging a critical transition. In survival analysis, the hazard ratio between the 97.5th percentile and the 2.5th percentile of MMD reached as high as 21.1 [95% CI: 14.3, 31.2], showing that higher variability indicates substantially higher mortality risk. Multivariate approaches to early warning signs of critical transitions hold substantial clinical promise to identify early signs of critical transitions, such as risk of death in hemodialysis patients; future work should also explore whether the MMD approach works in other complex systems (i.e., ecosystems, economies), and should compare it to other multivariate approaches to quantify system variability.

Variability in Hemoglobin Levels and the Factors Associated with Mortality in Hemodialysis Patients: A 78-Month Follow-Up Study

Some studies have described that when the hemoglobin levels of chronic kidney disease (CKD) patients change, especially in those taking erythropoiesis-stimulating agents (ESA), they are associated with unfavorable outcomes such as increased morbidity and mortality, mainly due to cardiovascular events. This prospective cohort study included patients with end-stage renal disease currently undergoing hemodialysis. The initial 6-month clinical evaluation provided data of the variability in hemoglobin, associated blood parameters, and the use of erythropoietin. Subsequently, the patients were followed up for 78 months to evaluate mortality-associated factors. In total, 133 patients completed the 6-month follow-up with a mean age of 47.1 (±13.2) years. The majority were women (51.9%). Six-month hemoglobin levels were as follows: always low (18.0%), intermediate/target (1.5%), always high (0.8%), low-amplitude fluctuation/Hb low (n = 37; 27.8%), low-amplitude fluctuation/Hb high (13.53%), and high-amplitude fluctuation (38.6%), among end-stage renal disease patients. At the end of 78 months, 50 (37.6%) patients died; 70% of deaths were attributed to cardiovascular etiologies. A high variability was observed in hemoglobin levels, which was not associated with mortality. Among all the variables evaluated, age, erythropoietin dose, and transferrin saturation were associated with a higher mortality. Thus, this study suggests that greater attention to erythropoietin doses and transferrin saturation levels may improve the survival of dialysis patients.

Predialysis Potassium Variability and Postdialysis Mortality in Patients With Advanced CKD

Introduction

Patients with advanced non–dialysis-dependent chronic kidney disease (NDD-CKD) are prone to potassium (K) imbalances due to reduced kidney function. Both hypo- and hyperkalemia are associated with increased mortality; however, it is unclear if K variability before dialysis initiation is associated with outcomes after dialysis initiation.

Methods

We identified 34,167 US veterans with advanced NDD-CKD transitioning to dialysis between October 1, 2007, through March 31, 2015, who had at least 1 K measurement each year over a 3-year period before transition (3-year prelude). For each patient, a linear mixed-effects model was used to regress K over time (in years) over the 3-year prelude to derive K variability (square root of the average squared distance between the observed and estimated K). The main outcomes of interest were 6-month all-cause and cardiovascular mortality after dialysis initiation. Multivariable Cox and Fine-Gray competing risk regression adjusted for 3-year prelude K intercept, K slope (per year), demographics, smoking status, comorbidities, length of hospitalizations, body mass index, vascular access type, medications, average estimated glomerular filtration rate, and number of K measurements over the 3-year prelude were used to assess the association of K variability (expressed as quartiles) with all-cause and cardiovascular mortality, respectively.

Results

Higher prelude K variability was associated with higher multivariable-adjusted risk of all-cause mortality but not cardiovascular mortality (adjusted hazard/subhazard ratios [95% confidence interval] for highest quartile [vs. lowest] of K variability, 1.14 [1.03–1.25] and 0.99 [0.85–1.16] for all-cause and cardiovascular mortality, respectively).

Conclusion

Higher K variability is associated with higher all-cause mortality after dialysis initiation.

The Impact of CKD Anaemia on Patients: Incidence, Risk Factors, and Clinical Outcomes-A Systematic Literature Review

Anaemia is a common consequence of chronic kidney disease (CKD); however, the risk factors for its development and its impact on outcomes have not been well synthesised. Therefore, we undertook a systematic review to fully characterise the risk factors associated with the presence of anaemia in patients with CKD and a contemporary synthesis of the risks of adverse outcomes in patients with CKD and anaemia. We searched MEDLINE, EMBASE, and the Cochrane Library from 2002 until 2018 for studies reporting the incidence or prevalence of anaemia and associated risk factors and/or associations between haemoglobin (Hb) or anaemia and mortality, major adverse cardiac events (MACE), hospitalisation, or CKD progression in adult patients with CKD. Extracted data were summarised as risk factors related to the incidence or prevalence of anaemia or the risk (hazard ratio (HR)) of outcome by Hb level (<10, 10-12, >12 g/dL) in patients not on dialysis and in those receiving dialysis. 191 studies met the predefined inclusion criteria. The risk factor most associated with the prevalence of anaemia was CKD stage, followed by age and sex. Mean HRs (95% CI) for all-cause mortality in patients with CKD on dialysis with Hb <10, 10-12, and >12 g/dL were 1.56 (1.43-1.71), 1.17 (1.09-1.26), and 0.91 (0.87-0.96), respectively. Similar patterns were observed for nondialysis patients and for the risks of hospitalisation, MACE, and CKD progression. This is the first known systematic review to quantify the risk of adverse clinical outcomes based on Hb level in patients with CKD. Anaemia was consistently associated with greater mortality, hospitalisation, MACE, and CKD progression in patients with CKD, and risk increased with anaemia severity. Effective treatments that not only treat the anaemia but also reduce the risk of adverse clinical outcomes are essential to help reduce the burden of anaemia and its management in CKD.

An analysis of the impact of fluid overload and fluid depletion for all-cause and cardiovascular mortality

BACKGROUND

Both baseline fluid overload (FO) and fluid depletion are associated with increased mortality risk and cardiovascular complications in haemodialysis patients. Fluid status may vary substantially over time, and this variability could also be associated with poor outcomes.

METHODS

In our retrospective cohort study, including 4114 haemodialysis patients from 34 Romanian dialysis units, we investigated both all-cause and cardiovascular mortality risk according to baseline pre- and post-dialysis volume status, changes in pre- and post-dialysis fluid status during follow-up (time-varying survival analysis), pre-post changes in volume status during dialysis and pre-dialysis fluid status variability during the first 6 months of evaluation.

RESULTS

According to their pre-dialysis fluid status, patients were stratified in the following groups: normovolaemic with an absolute FO (AFO) compartment between -1.1 and 1.1 L, fluid depletion with an AFO below -1.1 L, moderate FO with an AFO compartment >1.1 but <2.5 L and severe FO with the AFO compartment >2.5 L. Baseline pre-dialysis FO and fluid depletion patients had a significantly elevated risk of all-cause mortality risk {hazard ratio [HR] 1.53 [95% confidence interval (CI) 1.22-1.93], HR 2.04 (95% CI 1.59-2.60) and HR 1.88 (95% CI 1.07-3.39) for moderate FO, severe FO and fluid depletion, respectively}. In contrast, post-dialysis fluid depletion was associated with better survival [HR 0.71 (95% CI 0.57-0.89)]. Similar results were found when using changes in pre- or post-dialysis fluid status during follow-up (time-varying values): FO patients had an increased risk of all-cause [moderate FO: HR 1.39 (95% CI 1.11-1.75); severe FO: HR 2.29 (95% CI 2.01-3.31] and cardiovascular (CV) mortality [moderate FO: HR 1.34 (95% CI 1.05-1.70); severe FO: HR 2.34 (95% CI 1.67-3.28)] as compared with normohydrated patients. Using pre-post changes in volume status during dialysis, we categorized the patients into six groups: Group 1, AFO <-1.1 L pre- and post-dialysis; Group 2, AFO between -1.1 and 1.1 L pre-dialysis and <-1.1 L post-dialysis (the reference group); Group 3, AFO between -1.1 and 1.1 L pre- and post-dialysis; Group 4, AFO >1.1 L pre-dialysis and <-1.1 L post-dialysis; Group 5, AFO >1.1 L pre-dialysis and between -1.1 and 1.1 L post-dialysis; Group 6, AFO >1.1 L pre- and post-dialysis. Using the baseline values, only patients in Groups 1, 5 and 6 maintained an increased risk for all-cause mortality as compared with the reference group. Additionally, CV mortality risk was significantly higher for patients in Groups 5 and 6. When we applied the time-varying analysis, patients in Groups 1, 5 and 6 had a significantly higher risk for both all-cause and CV mortality risk. In the last approach, the highest risk for the all-cause mortality outcome was observed for patients with high-amplitude fluctuation during the first 6 months of evaluation [HR 2.75 (95% CI 1.29-5.84)].

CONCLUSION

We reconfirm the association between baseline pre- and post-dialysis volume status and mortality in dialysis patients; additionally, we showed that greater fluid status variability is independently associated with higher mortality.

Cerebral oxygenation improvement is associated with hemoglobin increase after hemodialysis initiation

INTRODUCTION

Near-infrared spectroscopy has been used to measure the regional oxygen saturation (rSO₂) of the brain, and decreases in cerebral rSO₂ have been reported to lead to cognitive impairment in patients undergoing hemodialysis. However, reports about the association between changes in cerebral oxygenation and clinical parameters at hemodialysis initiation, including hemoglobin level, are lacking.

METHODS

This study included 33 patients at the hemodialysis initiation phase. Cerebral rSO2 was monitored using an INVOS 5100C. Included patients were assessed twice (at hemodialysis initiation and 42.7 ± 20.8 days after the first measurement), and changes in cerebral rSO2 were compared with changes in clinical parameters.

RESULTS

Cerebral rSO2 at the second measurement significantly increased compared with that at hemodialysis initiation (57.2 ± 6.8% vs 54.4 ± 8.8%, p < 0.05). Changes in cerebral rSO2 represented a significant correlation with changes in hemoglobin level, pulse rate, and serum albumin level. Multivariate linear regression analysis was performed using significant factors in simple linear regression analysis. Changes in hemoglobin (standardized coefficient: 0.37) and serum albumin (standardized coefficient: 0.45) levels were identified as independent factors influencing the changes in cerebral rSO2.

CONCLUSION

Cerebral rSO2 was low in the presence of low hemoglobin levels at hemodialysis initiation and improved in response to hemoglobin increase in addition to changes in serum albumin levels. Attention should be paid to changes in hemoglobin levels even at hemodialysis initiation to prevent the deterioration of cerebral oxygenation, and this might contribute to the maintenance of cognitive function in patients undergoing hemodialysis.

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.

Real-world treatment patterns of renal anemia in hemodialysis patients: A multicenter cohort study performed using DialysisNet (RRAHD study)

A multicenter cohort study.The DialysisNet was previously developed for the management of hemodialysis (HD) patients based on the American Society for Testing and Materials Continuity of Care Records by metadata transformation. DialysisNet is a dialysis patient management program created by using the personal health record care platform to overcome the problems of registry studies, in real-time.Here, we aimed to investigate the pattern of treatment for renal anemia in HD patients using DialysisNet.We performed a multicenter cohort study among HD patients who were treated at one of the three Korean university-affiliated hospitals from January 2016 to December 2016. Subjects were divided into 4 hemoglobin variability groups by quartiles. The variable anemia treatment pattern was reviewed. To determine renal anemia treatment patterns, we automatically collected information on the practice of anemia treatment patterns such as erythropoietin stimulating agent (ESA) doses and administration frequencies, and targeted hemoglobin maintenance rate. Individual hemoglobin variabilities were expressed as (standard deviations)/(√(n/[n-1]).The records of 159 patients were analyzed (Hospital A: 35, Hospital B: 21, Hospital C: 103). Mean patients' age was 65.6 ± 12.8 years, and 61.6% were men. Overall, hemoglobin level was 10.5[7.43;13.93] g/dL. 158 (99.3%) patients were using ESA; and overall, the epoetin alfa dose was 33,000[4000;136,800] U per week. Hemoglobin levels (P = .206) and epoetin alfa doses were similar (P = .924) for patients with different hemoglobin variabilities. The hemoglobin target maintenance rate was lower in the highest hemoglobin variability group than in the lowest variability group (P = .045).In this study, detailed information on the actual anemia treatment patterns were obtained using the DialysisNet. We expect that DialysisNet will simplify and improve the renal anemia management for both dialysis patients and health care providers.

Association between long-term hemoglobin variability and mortality in Korean adults: a nationwide population-based cohort study

Hemoglobin variability is known to be associated with mortality in patients with chronic renal failure and cardiovascular disease. However, the effect of hemoglobin variability on mortality in the general population has not yet been studied. We aimed to investigate the association between hemoglobin variability and mortality using Korean cohort from National Health Insurance Service-Health Screening 2002–2015 database. This study was conducted on 182,757 adults who underwent more than 4 health screenings from 2002 to 2009. Hemoglobin variability was assessed by 3 indices of coefficient of variation (CV), standard deviation (SD), and variability independent of the mean (VIM). Cox proportional hazard regression analysis was performed for each index of quartile groups (Q1–Q4). The hazard ratio and 95% confidence interval^l for all-cause mortality comparing Q2, Q3 and Q4 with Q1 of hemoglobin variability CV in the multivariable adjusted model were 1.07 [0.96–1.20], 1.18 [1.06–1.31] and 1.43 [1.29–1.58] respectively. As the 5% CV, SD, and VIM increased, the hazard ratio for mortality increased by 1.08 [1.06–1.10] in the multivariable adjusted model. Hemoglobin variability is not only important predictor in patients with chronic renal failure and cardiovascular disease but could also be considered as a useful predictor of mortality in the general population.

Freestanding Dialysis Facility Quality Incentive Program Scores and Mortality Among Incident Dialysis Patients in the United States

RATIONALE & OBJECTIVE

The Centers for Medicare & Medicaid Services introduced the Quality Incentive Program (QIP) along with the bundled payment reform to improve the quality of dialysis care in the United States. The QIP has been criticized for using easily obtained laboratory indicators without patient-centered measures and for a lack of evidence for an association between QIP indicators and patient outcomes. This study examined the association between dialysis facility QIP performance scores and survival among patients after initiation of dialysis.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

Study participants included 84,493 patients represented in the US Renal Disease System's patient-level data who had initiated dialysis between January 1, 2013, and December 1, 2013, and who did not, during the first 90 days after dialysis initiation, die, receive a transplant, or become lost to follow-up. Patients were followed up for the study outcome through March 31, 2014.

PREDICTOR

Dialysis facility QIP scores.

OUTCOME

Mortality.

ANALYTICAL APPROACH

Using a unique facility identifier, we linked Medicare freestanding dialysis facility data from 2015 with US Renal Disease System patient-level data. Kaplan-Meier product limit estimator was used to describe the survival of study participants. Cox proportional hazards regression was used to assess the multivariable association between facility performance scores and patient survival.

RESULTS

Excluding patients who died during the first 90 days of dialysis, 11.8% of patients died during an average follow-up of 5 months. Facilities with QIP scores<45 (HR, 1.39; 95% CI, 1.15-1.68) and 45 to<60 (HR, 1.21; 95% CI, 1.10-1.33) had higher patient mortality rates than facilities with scores≥90.

LIMITATIONS

Because the Centers for Medicare & Medicaid Services have revised QIP criteria each year, the findings may not relate to years other than those studied.

CONCLUSIONS

Dialysis facilities characterized by lower QIP scores were associated with higher rates of patient mortality. These findings need to be replicated to assess their consistency over time.

Optimal EPO dosing in hemodialysis patients using a non-linear model predictive control approach

Anemia management with erythropoiesis stimulating agents is a challenging task in hemodialysis patients since their response to treatment varies highly. In general, it is difficult to achieve and maintain the predefined hemoglobin (Hgb) target levels in clinical practice. The aim of this study is to develop a fully personalizable controller scheme to stabilize Hgb levels within a narrow target window while keeping drug doses low to mitigate side effects. First in-silico results of this framework are presented in this paper. Based on a model of erythropoiesis we formulate a non-linear model predictive control (NMPC) algorithm for the individualized optimization of epoetin alfa (EPO) doses. Previous to this work, model parameters were estimated for individual patients using clinical data. The optimal control problem is formulated for a continuous drug administration. This is currently a hypothetical form of drug administration for EPO as it would require a programmable EPO pump similar to insulin pumps used to treat patients with diabetes mellitus. In each step of the NMPC method the open-loop problem is solved with a projected quasi-Newton method. The controller is successfully tested in-silico on several patient parameter sets. An appropriate control is feasible in the tested patients under the assumption that the controlled quantity is measured regularly and that continuous EPO administration is adjusted on a daily, weekly or monthly basis. Further, the controller satisfactorily handles the following challenging problems in simulations: bleedings, missed administrations and dosing errors.

A Microfluidic Deformability Assessment of Pathological Red Blood Cells Flowing in a Hyperbolic Converging Microchannel

The loss of the red blood cells (RBCs) deformability is related with many human diseases, such as malaria, hereditary spherocytosis, sickle cell disease, or renal diseases. Hence, during the last years, a variety of technologies have been proposed to gain insights into the factors affecting the RBCs deformability and their possible direct association with several blood pathologies. In this work, we present a simple microfluidic tool that provides the assessment of motions and deformations of RBCs of end-stage kidney disease (ESKD) patients, under a well-controlled microenvironment. All of the flow studies were performed within a hyperbolic converging microchannels where single-cell deformability was assessed under a controlled homogeneous extensional flow field. By using a passive microfluidic device, RBCs passing through a hyperbolic-shaped contraction were measured by a high-speed video microscopy system, and the velocities and deformability ratios (DR) calculated. Blood samples from 27 individuals, including seven healthy controls and 20 having ESKD with or without diabetes, were analysed. The obtained data indicates that the proposed device is able to detect changes in DR of the RBCs, allowing for distinguishing the samples from the healthy controls and the patients. Overall, the deformability of ESKD patients with and without diabetes type II is lower in comparison with the RBCs from the healthy controls, with this difference being more evident for the group of ESKD patients with diabetes. RBCs from ESKD patients without diabetes elongate on average 8% less, within the hyperbolic contraction, as compared to healthy controls; whereas, RBCs from ESKD patients with diabetes elongate on average 14% less than the healthy controls. The proposed strategy can be easily transformed into a simple and inexpensive diagnostic microfluidic system to assess blood cells deformability due to the huge progress in image processing and high-speed microvisualization technology.

[Impact of comorbidities on hemoglobin stability in patients with chronic kidney insufficiency on hemodialysis, treated with CERA in current practice: The MIRIADE study]

This national, prospective and multicenter study aimed to describe the real-life impact of comorbidities on hemoglobin stability in patients with chronic kidney disease on hemodialysis, treated with CERA in relay of an erythropoietin stimulating agent. Comorbidities were defined by the Charlson Index (adjusted on age) and hemoglobin stability as a variation of ±1g/dL after the 6-month treatment period. The 585 analyzed patients were distributed as follows according to the adjusted Charlson index: score≤3 (12% of patients), 4≤score≤5 (17%), 6≤score≤7 (31%) and score≥8 (40%). At CERA start, its median monthly dose was of 100μg for the overall population, with no changes during the treatment period and with little variation according to the comorbidity score. Patients with stable hemoglobin (56%, 67% if score≤3) were more numerous to reach the therapeutic target range between 10 and 12g/dL after 6 months (85% versus 43% if not stable hemoglobin). Patients with low C-reactive protein value (≤5mg/L ; P=0.04), no red blood cell transfusion (P=0.03), or no/low dose of intravenous iron (≤200mg ; P=0.03) were more likely to reach stable hemoglobin under CERA after 6 months. Among the 644 CERA-treated patients, 4 patients (<1%) had one serious adverse event related to treatment. A stable hemoglobin within the therapeutic target was reached in the majority of the patients after 6 months in current practice with a lower CERA dose, regardless of the comorbidities scores of patients on hemodialysis.

Haemoglobin variability and all-cause mortality in haemodialysis patients: A systematic review and meta-analysis

Aim

Haemoglobin (Hb) variability has been reported to be associated with mortality in dialysis patients in some but not all studies. We aimed to establish the prognostic significance of Hb variability with all‐cause mortality in haemodialysis patients through this meta‐analysis.

Methods

The Medline, Embase, Cochrane Library and Web of Science databases were searched for studies assessing the association between Hb variability and all‐cause mortality in haemodialysis patients after adjustment for other covariates.

Results

We included three studies of five cohorts with a total of 262 641 patients. Forest plots showed that the combined hazard ratio for all‐cause mortality was 1.09 (95% CI = 1.01–1.08; P = 0.03) per 1 g/dL increase in Hb variability.

Conclusion

Based on the current evidence, our meta‐analysis found an association between Hb variability and all‐cause mortality in patients receiving haemodialysis therapy.

Three studies of five cohorts with a total of 262 641 patients showed a combined hazard ratio for all‐cause mortality in HD patients to be 1.09 (95% CI = 1.01–1.08; P = 0.03) per 1 g/dL increase in the haemoglobin level. A significant heterogeneity exists between the studies.

Statistical methods for building better biomarkers of chronic kidney disease

The last two decades have witnessed an explosion in research focused on the development and assessment of novel biomarkers for improved prognosis of diseases. As a result, best practice standards guiding biomarker research have undergone extensive development. Currently, there is great interest in the promise of biomarkers to enhance research efforts and clinical practice in the setting of chronic kidney disease, acute kidney injury, and glomerular disease. However, some have questioned whether biomarkers currently add value to the clinical practice of nephrology. The current state of the art pertaining to statistical analyses regarding the use of such measures is critical. In December 2014, the National Institute of Diabetes and Digestive and Kidney Diseases convened a meeting, "Toward Building Better Biomarker Statistical Methodology," with the goals of summarizing the current best practice recommendations and articulating new directions for methodological research. This report summarizes its conclusions and describes areas that need attention. Suggestions are made regarding metrics that should be commonly reported. We outline the methodological issues related to traditional metrics and considerations in prognostic modeling, including discrimination and case mix, calibration, validation, and cost-benefit analysis. We highlight the approach to improved risk communication and the value of graphical displays. Finally, we address some "new frontiers" in prognostic biomarker research, including the competing risk framework, the use of longitudinal biomarkers, and analyses in distributed research networks.

Definition and Validation of a Novel Metric of Erythropoiesis-Stimulating Agent Response in Hemodialysis Patients

Erythropoiesis-stimulating agents (eg, epoetin alfa) are the primary treatment for anemia in patients with end-stage renal disease. Hemoglobin variability in and out of a narrow target range is common and associated with higher morbidity and mortality risk. More robust erythropoiesis-stimulating agent response metrics are needed to define optimal dosing and their association with clinical outcomes. In this cross-sectional, single-center, retrospective study, 49 patients with end-stage renal disease on hemodialysis were followed over 12 months. To quantify hemoglobin deviations outside the target range (10-12 g/dL), the area under the curve of hemoglobin versus time over a 12-month period (AUC-HGB) was calculated using the trapezoidal rule. Patients were categorized into 4 responder groups based on AUC-HGB quartiles. Comparative analyses of demographic and clinical characteristics between responder groups were performed. Correlations between AUC-HGB, erythropoietin resistance index, and time within therapeutic range were calculated. There were no significant differences in laboratory and dialysis parameters between responder groups except hemoglobin concentration and epoetin alfa dose. There was a negative correlation between AUC-HGB and time within therapeutic range (r = -.92; P < .001) and hemoglobin concentration (r = -.85; P < .01), indicating internal validity of the metric. There was a positive correlation between AUC-HGB and erythropoietin resistance index (r = .70; P < .001) indicating external validity. The poor response group received a higher median epoetin alfa dose (160 U/kg/week) compared to the excellent response group (68.8 U/kg/week; P < .001) with a similar number of dose changes between the groups. AUC-HGB is a valid marker of epoetin alfa response and should be considered in future analyses of larger populations.

Impact of hemoglobin variability on cardiovascular mortality in maintenance hemodialysis patients

PURPOSE

Although the association between anemia and cardiovascular mortality in hemodialysis patients is well established, whether hemoglobin variability (Hgb-Var) affects the prognosis remains unclear. We aimed to evaluate the association between Hgb-Var and cardiovascular mortality in Chinese hemodialysis patients.

METHODS

This retrospective study included 252 patients starting hemodialysis in Xin Hua Hospital between January 2009 and December 2015. Patients were divided into three tertiles based on Hgb-Var, as reflected by SD Hgb_mean, SD Hgb_range, and Hgb_deflection during a 12-month evaluation period after hemodialysis initiation. Left ventricular ejection fraction (EF) and left ventricular mass index (LVMI) were evaluated by echocardiography. Information on cardiovascular deaths occurred by December 2017 was collected. Multivariate Cox regression models were constructed to evaluate the association between Hgb-Var and cardiovascular mortality.

RESULTS

A total of 75 deaths and 52 cardiovascular deaths occurred during the 47-month follow-up (range 29.5-70). Under multivariate regression, the subgroup with the highest Hgb-Var had a higher risk of cardiovascular mortality after adjusting for relevant factors (HR vs. lowest SD Hgb_mean: 9.15, 95% CI 2.82, 29.693, P < 0.0001; HR vs. lowest SD Hgb_range: 3.81, 95% CI 1.40, 10.38, P = 0.005). Per 1 SD of Hgb_mean and Hgb_range elevations were both related to a 10% increase in the cardiovascular mortality risk. Baseline EF% and LVMI did not differ across the Hgb-Var subgroups. EF% upon the last patient visit to the clinic was lower in the subgroup with the highest SD Hgb_mean (P = 0.02).

CONCLUSIONS

High Hgb-Var is an independent risk factor for cardiovascular mortality in hemodialysis patients and might influence the cardiac function.

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.

Variability in hemoglobin levels in hemodialysis patients in the current era: a retrospective cohort study

Background: Given regulatory and reimbursement changes in anemia management, we examined hemoglobin variability in a contemporary cohort of maintenance hemodialysis patients. Materials and methods: The study population included > 200,000 hemodialysis patients with Medicare parts A and B as primary payer on October 1, 2012. Based on 25^th and 75^th percentiles, monthly hemoglobin values were categorized as low, intermediate, or high. Six variability categories were created by patterns during the 6-month observation period. Stable categories were: always-low, always-intermediate, always-high; variable patterns were: varying between low and intermediate, intermediate and high, low and high (most-variable). Cox proportional hazard models were used to assess the association between hemoglobin variability and all-cause mortality or major adverse cardiac events (MACE). Results: The 25^th and 75^th hemoglobin percentiles were 10.2 and 11.5 g/dL, respectively, in 2012, vs. 11 and 12.5 g/dL in 2004. ESA doses were lower in all categories in 2012 and transfusion rates higher, particularly for always-low patients. Hemoglobin variability decreased modestly: in 2004, 6.0% were always-intermediate, vs. 9.5% in 2012. In 2012, more patients were always-high and fewer were most-variable. Mortality hazard ratios (HRs) were higher for patients with any low hemoglobin: always-low (HR, 95% CI: 2.07, 1.84 – 2.31), varying between low and intermediate (1.37, 1.29 – 1.45), and most-variable (1.23, 1.16 – 1.31); the pattern was similar for MACE. Conclusions: In 2012 vs. 2004, hemoglobin levels decreased, the range of levels narrowed, and variability decreased modestly; transfusions increased. The highest risk of mortality and MACE appeared to occur in patients with persistently low, rather than highly variable, hemoglobin levels.


Evaluating the effectiveness of IV iron dosing for anemia management in common clinical practice: results from the Dialysis Outcomes and Practice Patterns Study (DOPPS)

Background

Anemia management protocols in hemodialysis (HD) units differ conspicuously regarding optimal intravenous (IV) iron dosing; consequently, patients receive markedly different cumulative exposures to IV iron and erythropoiesis-stimulating agents (ESAs). Complementary to IV iron safety studies, our goal was to gain insight into optimal IV iron dosing by estimating the effects of IV iron doses on Hgb, TSAT, ferritin, and ESA dose in common clinical practice.

Methods

9,471 HD patients (11 countries, 2009-2011) in the DOPPS, a prospective cohort study, were analyzed. Associations of IV iron dose (3-month average, categorized as 0, <300, ≥300 mg/month) with 3-month change in Hgb, TSAT, ferritin, and ESA dose were evaluated using adjusted GEE models.

Results

Relative change: Monotonically positive associations between IV iron dose and Hgb, TSAT, and ferritin change, and inverse associations with ESA dose change, were observed across multiple strata of prior Hgb, TSAT, and ferritin levels. Absolute change: TSAT, ferritin, and ESA dose changes were nearest zero with IV iron <300 mg/month, rather than 0 mg/month or ≥300 mg/month by maintenance or replacement dosing. Findings were robust to numerous sensitivity analyses.

Conclusions

Though residual confounding cannot be ruled out in this observational study, findings suggest that IV iron dosing <300 mg/month, as commonly seen with maintenance dosing of 100-200 mg/month, may be a more effective approach to support Hgb than the higher IV iron doses (300-400 mg/month) often given in many European and North American hemodialysis clinics. Alongside studies supporting the safety of IV iron in 100-200 mg/month dose range, these findings help guide the rational dosing of IV iron in anemia management protocols for everyday hemodialysis practice.

Electronic supplementary material

The online version of this article (10.1186/s12882-017-0745-9) contains supplementary material, which is available to authorized users.

Developing a classification system for haemoglobin management in patients with end-stage renal disease on haemodialysis: a secondary data analysis

BACKGROUND

Ongoing discussion on anaemia management and target haemoglobin (Hb) levels in patients on haemodialysis with erythropoietin treatment require a systematic approach in evaluating current practice. Aim of the present study was to develop a new classification system to easily monitor Hb trajectories and categorise patients on haemodialysis.

METHODS

Routine data from five dialysis centres in the USA collected between 2010 and 2016. Data were anonymised and only those from patients with fortnightly Hb values were included in the analysis. Entries on blood parameters and medication were standardised to achieve overall comparability. Data from each patient was grouped in periods of 120 days. Hb values above or below the target level of 10-12 g/dL were counted for each period. Periods were then assigned to Hb-classes according to the number of Hb values out of range per period: Hb-class I with 0-2, Hb-class II for 3-5 and Hb-class III for ≥6 values out of range.

RESULTS

Records from 3349 patients with fortnightly Hb values, information on haemodialysis data, laboratory parameters correlated to red blood cells and data on medication with erythropoiesis-stimulating agents (ESAs) were available. Patients were 64.4±15.9 years old; 55.0% were men. Statistical analysis revealed significant differences between Hb-classes in all of the examined parameters, except erythrocytes mean corpuscular volume and C reactive protein above the threshold, with more critical values in higher Hb-classes. The usage of ESAs showed a mean difference between Hb-class III and Hb-class I of 6.4 units/day and kilogram body weight in a 120-day period.

CONCLUSION

Our classification system allows an easily achievable overview of the patients' responsiveness and performance of Hb management. Integrated into a disease management programme or continuous quality improvement, the classification delivers an instant appraisal without complex statistical or mathematical processing.

Pre-End-Stage Renal Disease Hemoglobin Variability Predicts Post-End-Stage Renal Disease Mortality in Patients Transitioning to Dialysis

BACKGROUND

Hemoglobin variability (Hb-var) has been associated with increased mortality both in non-dialysis dependent chronic kidney disease (NDD-CKD) and end-stage renal disease (ESRD) patients. However, the impact of Hb-var in advanced NDD-CKD on outcomes after dialysis initiation remains unknown.

METHODS

Among 11,872 US veterans with advanced NDD-CKD transitioning to dialysis between October 2007 through September 2011, we assessed Hb-var calculated from the residual SD of at least 3 Hb values during the last 6 months before dialysis initiation (prelude period) using within-subject linear regression models, and stratified into quartiles. Outcomes included post-transition all-cause, cardiovascular, and infection-related mortality, assessed in Cox proportional hazards models and adjusted for demographics, comorbidities, length of hospitalization, medications, estimated glomerular filtration rate (eGFR), type of vascular access, Hb parameters (baseline Hb [i.e., intercept] and change in Hb [i.e., slope]), and number of Hb measurements.

RESULTS

Higher prelude Hb-var was associated with use of iron and antiplatelet agents, tunneled dialysis catheter use, higher levels of baseline Hb, change in Hb, eGFR, and serum ferritin. After multivariable adjustment, higher prelude Hb-var was associated with higher post-ESRD all-cause and infection-related mortality, but not cardiovascular mortality (adjusted hazard ratios [95% CI] for the highest [vs. lowest] quartile of Hb-var, 1.10 [1.02-1.19], 1.28 [0.93-1.75], and 0.93 [0.79-1.10], respectively).

CONCLUSIONS

High pre-ESRD Hb-var is associated with higher mortality, particularly from infectious causes rather than cardiovascular causes. Further research is required to clarify the underlying mechanisms and true causal nature of the observed association.

The role of hemoglobin variability as a prognostic indicator in peritoneal dialysis patients: a retrospective descriptive study

PURPOSE

To investigate the effect of hemoglobin fluctuations on cardiovascular prognosis of patients on peritoneal dialysis (PD).

METHODS

Retrospective descriptive study, with sample composed of 333 patients treated with PD at the Renal Unit. Two indicators were adopted to indicate hemoglobin fluctuations of PD patients: absolute value of hemoglobin variability (HV) and HV trend. Moreover, the new cardiovascular events and recurrent rate of cardiovascular events within 3 months after PD were recorded and were compared in groups of PD patients classified by hemoglobin fluctuation indicators.

RESULTS

Patients whose HV value is less than 10 g/l have an increased risk of new cardiovascular events than patients with HV value > 10 g/l (27.2 vs. 12.2%, p < 0.05) during 3 months after PD. Patients who kept high hemoglobin values (≥ 110 g/l) 3 months after PD are prone to develop recurrent cardiovascular events than patients with relatively low hemoglobin values (< 110 g/l; p < 0.05).

CONCLUSIONS

Hemoglobin fluctuations were associated with the cardiovascular prognosis in patients on PD. A limitation of our study is its retrospective design. However, the results in this research indicated anemia in PD patients without cardiovascular events history should be timely treated. Instead, hemoglobin should be kept within a relatively low level in patients with history of cardiovascular events. Additional clinical researches are needed to verify and improve our findings.

Aging and death-associated changes in serum albumin variability over the course of chronic hemodialysis treatment

Background

Several epidemiological studies have demonstrated associations between variability in a number of biological parameters and adverse outcomes. As the variability may reflect impaired homeostatic regulation, we assessed albumin variability over time in chronic hemodialysis (HD) patients.

Methods

Data from 1346 subjects who received chronic HD treatment from May 2001 to February 2015 were analyzed according to three phases of HD treatment: post-HD initiation, during maintenance HD treatment, and before death. The serum albumin values were grouped according to the time interval from HD initiation or death, and the yearly trends for both the albumin levels and the intra-individual albumin variability (quantified by the residual coefficient of variation: Alb-rCV) were examined. The HD initiation and death-associated changes were also analyzed using generalized additive mixed models. Furthermore, the long-term trend throughout the maintenance treatment period was evaluated separately using linear regression models.

Results

Albumin levels and variability showed distinctive changes during each of the 3 periods. After HD initiation, albumin variability decreased and reached a nadir within a year. During the subsequent maintenance treatment period (interquartile range = 5.2–11.0 years), the log Alb-rCV showed a significant upward trend (mean slope: 0.011 ± 0.035 /year), and its overall mean was -1.49 ± 0.08 (equivalent to an Alb-rCV of 3.22%). During the 1–2 years before death, this upward trend clearly accelerated, and the mean log Alb-rCV in the last year of life was -1.36 ± 0.17. The albumin levels and variability were negatively correlated with each other and exhibited exactly opposite movements throughout the course of chronic HD treatment. Different from the albumin levels, albumin variability was not dependent on chronological age but was independently associated with an individual’s aging and death process.

Conclusion

The observed upward trend in albumin variability seems to be consistent with a presumed aging-related decline in homeostatic capacity.

The relation between hemoglobin variability and carotid intima-media thickness in chronic hemodialysis patients

PURPOSE

Hemoglobin variability is a common problem among hemodialysis patients. We have previously demonstrated an association between Hb variability and left ventricular mass index. In this study, we investigated a possible relation between Hb variability and carotid intima-media thickness (CIMT).

METHODS

Twelve-month hemoglobin (Hb) values of 135 patients on maintenance hemodialysis were examined retrospectively. The range of 11-12 gr/dl was accepted as normal according to the KDOQI guidelines. Hemoglobin levels were classified as: Hb < 11 gr/dl:Low, Hb = 11-12 gr/dl:Normal and Hb > 12 gr/dl:High. According to 12-month Hb trajectory, the patients were divided into three groups: low-normal (LN), normal-high (NH) and low-high (LH). The CIMT measurements were taken on common carotid arteries bilaterally, and the average of these measurements were taken. The groups were compared in terms of CIMT measurements, demographic and laboratory features.

RESULTS

The LN, NH and LH groups were similar in terms of age, gender, incidence of diabetes mellitus, hypertension and cardiovascular diseases. Duration of hemodialysis, hemodialysis adequacy, serum lipids and CaxP products were also similar among the groups. The mean CIMT value was 0.601 ± 0.107, 0.744 ± 0.139 and 0.604 ± 0.134 mm in the LN, LH and NH groups, respectively (p < 0.001). CIMT was significantly higher in LH than in the other two groups.

CONCLUSIONS

In our study, when the three groups with similar risk factors for atherosclerosis were examined, we found that the LH group with the highest hemoglobin variability has the highest CIMT. This study is the first study to demonstrate that Hb variability is associated with an increase in CIMT in HD patients.

An international observational study suggests that artificial intelligence for clinical decision support optimizes anemia management in hemodialysis patients

Managing anemia in hemodialysis patients can be challenging because of competing therapeutic targets and individual variability. Because therapy recommendations provided by a decision support system can benefit both patients and doctors, we evaluated the impact of an artificial intelligence decision support system, the Anemia Control Model (ACM), on anemia outcomes. Based on patient profiles, the ACM was built to recommend suitable erythropoietic-stimulating agent doses. Our retrospective study consisted of a 12-month control phase (standard anemia care), followed by a 12-month observation phase (ACM-guided care) encompassing 752 patients undergoing hemodialysis therapy in 3 NephroCare clinics located in separate countries. The percentage of hemoglobin values on target, the median darbepoetin dose, and individual hemoglobin fluctuation (estimated from the intrapatient hemoglobin standard deviation) were deemed primary outcomes. In the observation phase, median darbepoetin consumption significantly decreased from 0.63 to 0.46 μg/kg/month, whereas on-target hemoglobin values significantly increased from 70.6% to 76.6%, reaching 83.2% when the ACM suggestions were implemented. Moreover, ACM introduction led to a significant decrease in hemoglobin fluctuation (intrapatient standard deviation decreased from 0.95 g/dl to 0.83 g/dl). Thus, ACM support helped improve anemia outcomes of hemodialysis patients, minimizing erythropoietic-stimulating agent use with the potential to reduce the cost of treatment.

Naturally nonanemic dialysis patients: Who are they?

Introduction Not only anemia, but also erythropoiesis stimulating agent (ESA)s for treating anemia may adversely affect prognosis of chronic hemodialysis patients. Various features of naturally (with no ESA usage) nonanemic patients may be useful for defining several factors in the pathogenesis of anemia. Methods Data, retrieved from the European Clinical Database (EuCliD)-Turkey on naturally nonanemic prevalent chronic hemodialysis patients (n: 201) were compared with their anemic (those who required ESA treatment) counterparts (n: 3948). Findings Mean hemoglobin values were 13.5 ± 0.8 and 11.5 ± 0.9 g/dL in nonanemic and anemic patients, respectively (P < 0.001). Nonanemia status was associated with younger age, male gender, longer dialysis vintage, nondiabetic status, more frequent hepatitis-C virus seropositivity and more frequent arteriovenous fistula usage. Serum ferritin and CRP levels and urea reduction ratio were higher in ESA-requiring patients. One (99%) and two (95.3%) years survival rates of the "naturally nonanemic" patients were superior as compared to anemics (91.0% and 82.6%, respectively), (P < 0.001). Discussion "Naturally nonanemic" status is associated with better survival in prevalent chronic hemodialysis patients; underlying mechanisms in this favorable outcome should be investigated by randomized controlled trials including large number of patients.

Effects of acceptance of disability on death or dialysis in chronic kidney disease patients: a 3-year prospective cohort study

Background

Acceptance of disability (AOD) is a useful construct that assesses the ability of a patient to psychologically cope with chronic diseases, but its effect on long-term outcomes of patients with chronic kidney disease (CKD) remains unclear. This study aimed to evaluate the relation between AOD level and clinical outcomes in a cohort of CKD patients in Taiwan.

Methods

262 CKD patients without dialysis at a hospital in Taiwan were consecutively recruited, from 2010 to 2011, and followed up for 3 years. At enrollment, demographic and clinical data were obtained, including baseline level measurement of AOD, using the Acceptance of Disability Scale-Revised (AODS-R). During follow-up, the authors assessed the effect of AOD on progression to dialysis and all-cause mortality by using Cox proportional hazard regression analysis.

Results

Of the patients included in the analyses, 145 (55.3 %) whose total scores of AOD were below the median (86.00) were regarded as having low AOD at enrollment. At the end of 3-year follow-up, 25 have died and 57 initiated dialysis. Participants with low AOD were more likely to have the composite end-point of progression to dialysis or death (adjusted hazard ratios [AHR] = 1.89, 95 % confidence interval [CI]: 1.18-3.20). In addition, CKD stage at IV or above and hemoglobin level were found to be associated with the occurrence of the composite end-point.

Conclusion

AOD was associated with an increased risk for poor clinical outcomes, thus suggesting that prompt awareness and management of the psychological reactions may improve clinical outcomes of patients with CKD.

Assessment of hemoglobin responsiveness to epoetin alfa in patients on hemodialysis using a population pharmacokinetic pharmacodynamic model

A population pharmacokinetic pharmacodynamic (PK/PD) model describing the effect of epoetin alfa on hemoglobin (Hb) response in hemodialysis patients was developed. Epoetin alfa pharmacokinetics was described using a linear 2-compartment model. PK parameter estimates were similar to previously reported values. A maturation-structured cytokinetic model consisting of 5 compartments linked in a catenary fashion by first-order cell transfer rates following a zero-order input process described the Hb time course. The PD model described 2 subpopulations, one whose Hb response reflected epoetin alfa dosing and a second whose response was unrelated to epoetin alfa dosing. Parameter estimates from the PK/PD model were physiologically reasonable and consistent with published reports. Numerical and visual predictive checks using data from 2 studies were performed. The PK and PD of epoetin alfa were well described by the model.

Successful creation of an anemia management algorithm for hemodialysis patients

INTRODUCTION

Several anemia guidelines for hemodialysis patients have recommended a target hemoglobin (Hb) range of 10-12 g/dL. However, maintaining Hb values continuously within a narrow target has been difficult, and there has been no generally accepted anemia management algorithm for hemodialysis patients.

METHODS

In our study, we created an anemia management algorithm that considers the length of erythrocyte lifetimes, focuses on the combination of erythropoiesis-stimulating agent management and iron administration, and prevents iron deficiency and overload. Our algorithm established a target Hb range of 10-12 g/dL.

RESULTS

We evaluated our algorithm in 49 patients for 6 months. The mean Hb values were approximately 11 g/dL during our study period. The percentage of patients in the target Hb range of 10-12 g/dL increased from 77.6% (38 of 49) at baseline to 85.7% (42 of 49) at 4-6 months. Throughout monthly regular blood tests during 1-6 months after we introduced our algorithm, Hb values remained within the target range in 55.1% (27 of 49) of patients. The standard deviation of Hb values significantly decreased at 5 and 6 months (P=0.013 and P=0.047, respectively; 1 g/dL at 0 month, 0.7 g/dL at 5 months, and 0.7 g/dL at 6 months). Our algorithm also succeeded in suppressing cumulative doses of iron (≤800 mg) and decreasing the ferritin values significantly (P=0.011). There were no significant differences in erythropoiesis-stimulating agent doses between 0 and 6 months (P=0.357).

CONCLUSION

Our anemia management algorithm successfully increased the number of patients in the target Hb range, significantly decreased the Hb standard deviation, suppressed cumulative doses of iron, and decreased ferritin values. These results suggest a better prognosis for hemodialysis patients. Further studies are required to evaluate our algorithm.

Progressive rise in red blood cell distribution width predicts mortality and cardiovascular events in end-stage renal disease patients

Red blood cell distribution width (RDW) is a robust marker of adverse clinical outcomes in various populations. However, the clinical significance of a progressive rise in RDW is undetermined in end-stage renal disease (ESRD) patients. The purpose of this study was to determine the prognostic importance of a change in RDW in ESRD patients. Three hundred twenty-six incident dialysis patients were retrospectively analyzed. Temporal changes in RDW during 12 months after dialysis initiation were assessed by calculating the coefficients by linear regression. Patients were divided into two groups: an RDW-decreased group who had negative coefficient values (n = 177) and an RDW-increased group who had positive values (n = 149). The associations between rising RDW and mortality and cardiovascular (CV) events were investigated. During a median follow-up of 2.7 years (range, 1.0–7.7 years), 75 deaths (24.0%) and 60 non-fatal CV events (18.4%) occurred. The event-free survival rate for the composite of end-points was lower in the RDW-increased group (P = 0.004). After categorizing patients according to baseline RDW, the event-free survival rate was lowest in patients with a baseline RDW >14.9% and increased RDW, and highest in patients with a baseline RDW ≤14.9% and decreased RDW (P = 0.02). In multivariate analysis, rising RDW was independently associated with the composite of end-points (hazard ratio = 1.75, P = 0.007), whereas the baseline RDW was not. This study shows that a progressive rise in RDW independently predicted mortality and CV events in ESRD patients. Rising RDW could be an additive predictor for adverse CV outcomes ESRD patients.

Survival patterns of lead-exposed workers with end-stage renal disease from Adult Blood Lead Epidemiology and Surveillance program

BACKGROUND

One previous study has shown that patients with end-stage renal disease (ESRD) with higher blood lead levels (BLLs) have shorter survival, in a cohort without occupational exposure where follow-up began an average of 5 years after dialysis (a survivor population).

METHODS

The authors studied individuals with at least 1 blood lead test who were part of an occupational lead surveillance program sponsored by the National Institute for Occupational Safety and Health and were diagnosed with ESRD. The authors studied the effect of BLL on survival from time of ESRD diagnosis after adjusting for potential confounders. Cox proportional hazards models were run, in which death was the end point and follow-up time was the time variable.

RESULTS

There were 434 ESRD cases with 82% males, 65% white and 31% African American; 51% had 1 blood test, whereas the remainder had a median of 5 tests. The median years of follow-up were 2.7 years with 219 deaths in the cohort. After adjusting for covariates (eg, transplantation status, age at diagnosis, glomerular filtration rate, comorbidities and ethnicity), the authors found no significant association between highest measured BLL and mortality across categories; 0 to <5 μg/dL (hazard ratio [HR] = 1.00), 5 to <25 μg/dL (HR = 1.09; 95% confidence interval [CI]: 0.70-1.70), 25 to <40 μg/dL (HR = 1.28; 95% CI: 0.81-2.02), 40 to <50 μg/dL (HR = 0.89; 95% CI: 0.48-1.63) and 50+ μg/dL (HR = 1.09; 95% CI: 0.66-1.81).

CONCLUSIONS

The authors found no association between BLL and survival after ESRD diagnosis. The authors' finding differs from earlier findings, possibly because the cohort had higher blood leads (25 versus 10 μg/dL), follow-up began at the time of ESRD diagnosis, and BLLs were measured before ESRD incidence.

Iron-hepcidin dysmetabolism, anemia and renal hypoxia, inflammation and fibrosis in the remnant kidney rat model

Anemia is a common complication of chronic kidney disease (CKD) that develops early and its severity increases as renal function declines. It is mainly due to a reduced production of erythropoietin (EPO) by the kidneys; however, there are evidences that iron metabolism disturbances increase as CKD progresses. Our aim was to study the mechanisms underlying the development of anemia of CKD, as well as renal damage, in the remnant kidney rat model of CKD induced by 5/6 nephrectomy. This model of CKD presented a sustained degree of renal dysfunction, with mild and advanced glomerular and tubulointerstitial lesions. Anemia developed 3 weeks after nephrectomy and persisted throughout the protocol. The remnant kidney was still able to produce EPO and the liver showed an increased EPO gene expression. In spite of the increased EPO blood levels, anemia persisted and was linked to low serum iron and transferrin levels, while serum interleukin (IL)-6 and high sensitivity C-reactive protein (hs-CRP) levels showed the absence of systemic inflammation. The increased expression of duodenal ferroportin favours iron absorption; however, serum iron is reduced which might be due to iron leakage through advanced kidney lesions, as showed by tubular iron accumulation. Our data suggest that the persistence of anemia may result from disturbances in iron metabolism and by an altered activity/function of EPO as a result of kidney cell damage and a local inflammatory milieu, as showed by the increased gene expression of different inflammatory proteins in the remnant kidney. In addition, this anemia and the associated kidney hypoxia favour the development of fibrosis, angiogenesis and inflammation that may underlie a resistance to EPO stimuli and reduced iron availability. These findings might contribute to open new windows to identify putative therapeutic targets for this condition, as well as for recombinant human EPO (rHuEPO) resistance, which occurs in a considerable percentage of CKD patients.

Variability in estimated glomerular filtration rate values is a risk factor in chronic kidney disease progression among patients with diabetes

Background

It is unknown whether variability of estimated Glomerular Filtration Rate (eGFR) is a risk factor for dialysis or death in patients with chronic kidney disease (CKD). This study aimed to evaluate variability of estimated Glomerular Filtration Rate (eGFR) as a risk factor for dialysis or death to facilitate optimum care among high risk patients.

Methods

A longitudinal retrospective cohort study of 70,598 Veterans Health Administration veteran patients with diabetes and CKD (stage 3–4) in 2000 with up to 5 years of follow-up. VHA and Medicare files were linked to derive study variables. We used Cox proportional hazards models to evaluate association between time to initial dialysis/death and key independent variables: time-varying eGFR variability (measured by standard deviation (SD)) and eGFR means and slopes while adjusting for prior hospitalizations, and comorbidities.

Results

There were 76.7% older than 65 years, 97.5% men, and 81.9% Whites. Patients were largely in early stage 3 (61.2%), followed by late stage 3 (28.9%), and stage 4 (9.9%); 29.1%, 46.8%, and 73.3%, respectively, died or had dialysis during the follow-up. eGFR SDs (median: 5.8, 5.1, and 4.0 ml/min/1.73 m² ) and means (median: 54.1, 41.0, 27.2 ml/min/1.73 m²) from all two-year moving intervals decreased as CKD advanced; eGFR variability (relative to the mean) increased when CKD progressed (median coefficient of variation: 10.9, 12.8, and 15.4). Cox regressions revealed that one unit increase in a patient’s standard deviation of eGFRs from prior two years was significantly associated with about 7% increase in risk of dialysis/death in the current year, similarly in all three CKD stages. This was after adjusting for concurrent means and slopes of eGFRs, demographics, prior hospitalization, and comorbidities. For example, the hazard of dialysis/death increased by 7.2% (hazard ratio:1.072; 95% CI = 1.067, 1.080) in early stage 3.

Conclusion

eGFR variability was independently associated with elevated risk of dialysis/death even after controlling for eGFR means and slopes.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-015-0025-5) contains supplementary material, which is available to authorized users.

Mortality risk of darbepoetin alfa versus epoetin alfa in patients with CKD: systematic review and meta-analysis

BACKGROUND

Epoetin alfa (EPO) and darbepoetin alfa (DPO) are erythropoiesis-stimulating agents that are widely and interchangeably used for the treatment of anemia in patients with advanced chronic kidney disease and end-stage renal disease. No study has specifically compared the risks of hard study outcomes between EPO and DPO, including mortality.

STUDY DESIGN

Systematic review of the literature and meta-analysis.

SETTING & POPULATION

Patients enrolled in randomized trials comparing EPO versus DPO for the treatment of anemia in adults with chronic kidney disease, including those requiring dialysis.

SELECTION CRITERIA FOR STUDIES

We conducted a systematic search of the literature (PubMed, CENTRAL, SCOPUS, and EMBASE, all years) and industry resources, using predefined search terms and data abstraction tools. We then summarized key characteristics and findings of these trials and performed a random-effects meta-analysis of trials with at least 3 months' duration to identify the summary OR of mortality between patients randomly assigned to DPO versus EPO.

INTERVENTION

DPO versus EPO.

OUTCOME

All-cause mortality.

RESULTS

We identified 9 trials that met the stated inclusion criteria. Overall, 2,024 patients were included in the meta-analysis, of whom 126 died during follow-up, which ranged from 20 to 52 weeks. We found no significant difference in mortality between patients randomly assigned to DPO versus EPO (OR, 1.33; 95% CI, 0.88-2.01). No treatment heterogeneity across studies was detected (Q statistic=4.60; P=0.8).

LIMITATIONS

Generalizability to nontrial populations is uncertain.

CONCLUSIONS

Few trials directly comparing DPO and EPO have been conducted and follow-up was limited. In aggregate, no effect of specific erythropoiesis-stimulating agent on mortality was identified, but the confidence limits were wide and remained compatible with considerable harm from DPO. Absent adequately powered randomized trials, observational postmarketing comparative effectiveness studies comparing these erythropoiesis-stimulating agents are required to better characterize the long-term safety profiles of these agents.

Benefits and risks of erythrocyte-stimulating agents

Chronic kidney disease (CKD) is a common and serious clinical problem. Anemia in patients with advanced CKD, frequently called renal anemia, causes disabling fatigue and diminishes patients’ quality of life. Frequent and excess transfusions or iron supplementation are potentially hazardous. Although it remains unclear whether the main factor in the development of renal anemia is the failure of erythropoietin (EPO) production in the kidney or a dysfunction in oxygen sensing exogenous EPO administration is considered a rational treatment. The advent of recombinant human erythropoietin (rHu-EPO) products has dramatically changed the therapeutic strategy for renal anemia. Although rHu-EPO therapy has improved patients’ quality of life and decreased the need for blood transfusions, some potential adverse effects have been reported till date. This brief review discusses the treatment of renal anemia with regard to the following: (1) historical background; (2) effectiveness of rHu-EPO; (3) some topics regarding the treatment of anemia, including EPO resistance, hemoglobin (Hb) cycling, and adequate Hb levels; (4) major adverse effects of rHu-EPO, including hypertension, thrombotic complications, and pure red cell aplasia; and (5) future problems to be resolved.

Effect of dialysis dose and membrane flux on hemoglobin cycling in hemodialysis patients

Many studies found that hemoglobin (Hb) fluctuation was closely related to the prognosis of the maintenance hemodialysis patients. We investigated the association of factors relating dialysis dose and dialyzer membrane with Hb levels. We undertook a randomized clinical trial in 140 patients undergoing thrice-weekly dialysis and assigned patients randomly to a standard or high dose of dialysis; Hb level was measured every month for 12 months. In the standard-dose group, the mean (±SD) urea reduction ratio was 65.1% ± 7.3%, the single-pool Kt/V was 1.26 ± 0.11, and the equilibrated Kt/V was 1.05 ± 0.09; in the high-dose group, the values were 73.5% ± 8.7%, 1.68 ± 0.15, and 1.47 ± 0.11, respectively. The standard deviation (SD) and residual SD (liner regression of Hb) values of Hb were significantly higher in the standard-dose group and low-flux group. The percentage achievement of target Hb in the high-dose dialysis group and high-flux dialyzer group was significantly higher than the standard-dose group and low-flux group, respectively. Patients undergoing hemodialysis thrice weekly appear to have benefit from a higher dialysis dose than that recommended by current KDQQI (Kidney Disease Qutcome Quality Initiative) guidelines or from the use of a high-flux membrane, which is in favor of maintaining stable Hb levels.