The urea reduction ratio and serum albumin concentration as predictors of mortality in patients undergoing hemodialysis

Sarcopenia: a major challenge in elderly patients with end-stage renal disease

Sarcopenia is a condition of multifaceted etiology arising in many elderly people. In patients with chronic kidney, the loss of muscle mass is much more intensive and the first signs of sarcopenia are observed in younger patients than it is expected. It is associated with the whole-body protein-energy deficiency called protein-energy wasting (PEW). It seems to be one of the major factors limiting patient's autonomy as well as decreasing the quality of life. If it cannot be treated with the simple methods requiring some knowledge and devotion, we will fail to save patients who die due to cardiovascular disease and infection, despite proper conduction of renal replacement therapy. Many factors influencing the risk of sarcopenia development have been evaluated in number of studies. Many studies also were conducted to assess the efficacy of different therapeutic strategies (diet, physical activity, hormones). Nevertheless, there is still no consensus on treatment the patients with PEW. Therefore, in the paper we present the reasons and pathophysiology of sarcopenia as an important element of protein energy wasting (PEW) in elderly patients suffering from chronic kidney disease. We also analyze possible options for treatment according to up-to-date knowledge.

Effect of GFR on plasma N-terminal connective tissue growth factor (CTGF) concentrations

BACKGROUND

Connective tissue growth factor (CTGF) has a key role in the pathogenesis of renal and cardiac fibrosis. Its amino-terminal fragment (N-CTGF), the predominant form of CTGF detected in plasma, has a molecular weight in the middle molecular range (18 kDa). However, it is unknown whether N-CTGF is a uremic retention solute that accumulates in chronic kidney disease (CKD) due to decreased renal clearance and whether it can be removed by hemodiafiltration.

STUDY DESIGN

4 observational studies in patients and 2 pharmacokinetic studies in rodents.

SETTING & PARTICIPANTS

4 single-center studies. First study (cross-sectional): 88 patients with CKD not receiving kidney replacement therapy. Second study (cross-sectional): 23 patients with end-stage kidney disease undergoing low-flux hemodialysis. Third study: 9 kidney transplant recipients before and 6 months after transplant. Fourth study: 11 low-flux hemodialysis patients and 12 hemodiafiltration patients before and after one dialysis session.

PREDICTOR

First, second, and third study: (residual) glomerular filtration rate (GFR). Fourth study: dialysis modality.

OUTCOMES & MEASUREMENTS

Plasma (N-)CTGF concentrations, measured by enzyme-linked immunosorbent assay.

RESULTS

In patients with CKD, we observed an independent association between plasma CTGF level and estimated GFR (β = -0.72; P < 0.001). In patients with end-stage kidney disease, plasma CTGF level correlated independently with residual kidney function (β = -0.55; P = 0.046). Successful kidney transplant resulted in a decrease in plasma CTGF level (P = 0.008) proportional to the increase in estimated GFR. Plasma CTGF was not removed by low-flux hemodialysis, whereas it was decreased by 68% by a single hemodiafiltration session (P < 0.001). Pharmacokinetic studies in nonuremic rodents confirmed that renal clearance is the major elimination route of N-CTGF.

LIMITATIONS

Observational studies with limited number of patients. Fourth study: nonrandomized, evaluation of the effect of one session; randomized longitudinal study is warranted.

CONCLUSION

Plasma (N-)CTGF is eliminated predominantly by the kidney, accumulates in CKD, and is decreased substantially by a single hemodiafiltration session.

Haemocompatibility and ion exchange capability of nanocellulose polypyrrole membranes intended for blood purification

Composites of nanocellulose and the conductive polymer polypyrrole (PPy) are presented as candidates for a new generation of haemodialysis membranes. The composites may combine active ion exchange with passive ultrafiltration, and the large surface area (about 80 m(2) g(-1)) could potentially provide compact dialysers. Herein, the haemocompatibility of the novel membranes and the feasibility of effectively removing small uraemic toxins by potential-controlled ion exchange were studied. The thrombogenic properties of the composites were improved by applying a stable heparin coating. In terms of platelet adhesion and thrombin generation, the composites were comparable with haemocompatible polymer polysulphone, and regarding complement activation, the composites were more biocompatible than commercially available membranes. It was possible to extract phosphate and oxalate ions from solutions with physiological pH and the same tonicity as that of the blood. The exchange capacity of the materials was found to be 600 ± 26 and 706 ± 31 μmol g(-1) in a 0.1 M solution (pH 7.4) and in an isotonic solution of phosphate, respectively. The corresponding values with oxalate were 523 ± 5 in a 0.1 M solution (pH 7.4) and 610 ± 1 μmol g(-1) in an isotonic solution. The heparinized PPy-cellulose composite is consequently a promising haemodialysis material, with respect to both potential-controlled extraction of small uraemic toxins and haemocompatibility.

Cyanate is a novel inducer of endothelial icam-1 expression

AIM

Recent work has shown that humans are significantly exposed to isocyanic acid/cyanate, which is generated when coal, biomass, or tobacco is burned. In vivo, cyanate is formed by the phagocyte protein myeloperoxidase and by breakdown of urea. Carbamylation of proteins through cyanate has been demonstrated to predict cardiovascular risk and is thought to promote vascular dysfunction; however, the underlying mechanisms remain unclear.

RESULTS

Here, we show that cyanate induces intercellular cell adhesion molecule-1 (ICAM-1) expression with subsequently enhanced neutrophil adhesion in human coronary artery endothelial cells. Cyanate triggers ICAM-1 expression through a mechanism depending on activation of the mitogen-activated protein kinase p38 and nuclear factor-kappaB. Endothelial ICAM-1 expression was not induced when low-molecular-weight substances were removed from cell culture medium, thus ruling out a role of carbamylated (lipo)proteins in ICAM-1 induction. In mice, oral administration of cyanate induced marked endothelial ICAM-1 expression in the aorta. Moreover, in patients with end-stage renal disease, the extent of plasma protein carbamylation (a marker for cyanate exposure) significantly correlated with plasma levels of soluble ICAM-1.

INNOVATION

Here, we demonstrate for the first time that cyanate, rather than carbamylated lipoproteins, induces vascular ICAM-1 expression in vivo.

CONCLUSION

Collectively, our data raise the possibility that cyanate amplifies vascular inflammation, linking inflammation, smoking, and uremia.

Hepatoprotetive, Cardioprotective and Nephroprotective Actions of Essential Oil Extract of Artemisia sieberi in Alloxan Induced Diabetic Rats

The aim of the current study is to evaluate the potential mechanism of antidiabetic action of the essential oil of Artemisia sieberi and its effects on some hematological and biochemical parameters in alloxan induced diabetic rats. Extraction of the essential oil from aerial parts of A. sieberi was preformed by hydrodistillation. Fifty rats were divided into five groups. Groups I and II normal rats given 1 mL/day of dimethyl sulfoxide and 80 mg/kg BW of this oil extract, respectively. Groups III, IV and V diabetic rats given 1 mL/day of dimethyl sulfoxide, oil extract (80 mg/kg BW) and metformin (14.2 mg/kg BW), respectively. Several hematological and biochemical parameters were assessed. Oral administration of the extract resulted in a significant reduction in the mean values of blood glucose, glucagon, cholesterol, triglyceride, LDL-C, ESR, urea, uric acid, creatinine accompanied by an increase in the mean values of the total protein, albumin, insulin, HDL-C, neutrophile count and PCV in diabetic rats. No significant changes in these parameters were found in the control group. The effects produced by this extract were closely similar to a standard antidiabetic drug, metformin. In conclusion, the present study indicates that the essential oil extract of A. sieberi appears to exhibit cardioprotective, nephroprotective and hepatoprotective activities in alloxan induced diabetic rats.

Nocturnal hemodialysis: analysis following the Frequent Hemodialysis Network trial

The recently concluded Frequent Hemodialysis Network (FHN) trials have demonstrated some striking and unexpected results. Both the daily arm and the nocturnal arm of the trial clearly demonstrated that frequent (daily or nightly) dialysis reduced blood pressure, reduced the number of antihypertensive medications, and reduced serum phosphorous concentration. One of the major questions addressed by these studies was the extent to which left ventricular mass was reduced by frequent dialysis. While the daily FHN trial showed a clear effect of frequent dialysis to reduce left ventricular mass, the nocturnal FHN trial produced inconclusive results. These apparently contradictory results are probably influenced by inadequate power and the somewhat skewed patient selection in the nocturnal arm. Patients in the nocturnal FHN trial had a shorter time on dialysis prior to enrollment, and greater residual renal function than did patients in the daily FHN trial. From a general perspective, it appears that there is minimal difference in the effect on left ventricular mass between frequent daily dialysis and nocturnal dialysis. The FHN trial was not designed to determine the effects of frequent dialysis on mortality. The analyses of this question using retrospective data strongly suggest that frequent dialysis prolongs life. The nephrology community now has the task to develop new ways to deliver improved therapy to patients on dialysis. This task will be challenging as resources for health care are constrained. New approaches to the care of such patients will be needed to realize the important conceptual advances embedded in the results of the FHN trials.

Albumin-binding capacity (ABiC) is reduced in patients with chronic kidney disease along with an accumulation of protein-bound uraemic toxins

BACKGROUND

Albumin is an important transport protein for non-water-soluble protein-bound drugs and uraemic toxins. Its transport capacity is reduced in patients with advanced chronic kidney disease (CKD) and unbound fractions of uraemic toxins are related to complications of CKD. We investigated whether this reduction could be quantified and how it correlated with the stages of CKD. Albumin-binding capacity (ABiC) is a dye-based method that quantifies the remaining binding capacity of one major binding site (site II) of the albumin molecule.

METHODS

Blood samples from 104 CKD patients were incubated with a binding site-specific fluorescent marker and the amount of unbound marker was determined by means of fluorescence detection after filtration. Measurements in a pooled human plasma were used for reference. Glomerular filtration rate and serum indoxyl sulphate (IS) levels were also determined.

RESULTS

Impairment of renal function was associated with a reduction in ABiC (mean ± SD: 118 ± 12; 111 ± 11; 99 ± 8 and 79 ± 9% for Stages 1/2, 3, 4 and 5, respectively; P < 0.001) and an increase in IS (3.9 ± 1.1; 6.2 ± 3.2; 16.3 ± 14.9 and 56.1 ± 28.6 μmol/L for Stages 1/2, 3, 4 and 5, respectively; P < 0.001). In dialysis patients, ABiC was lower in those with urine outputs <500 mL/day than in those with preserved urine output (73.7 ± 6.0 versus 83.8 ± 8.5%; P < 0.001).

CONCLUSION

Impaired albumin function in CKD patients can be quantified, is related to severity of kidney disease and is associated with an accumulation of uraemic albumin-bound retention solutes.

Longitudinal body composition changes due to dialysis

BACKGROUND AND OBJECTIVES

Nutritional status remains a powerful predictor of outcome in the dialysis population. High body mass index (BMI) seems protective, but which body compartment (fat or lean mass) confers this protection remains unclear.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This was a longitudinal study (n = 60; n = 46 completed) examining changes in body composition in incident peritoneal dialysis (PD) and hemodialysis (HD) patients over 12 months. We measured total body protein (TBP) by in vivo neutron activation, expressed as nitrogen index (NI), and lean body mass (LBM) and total body fat (TBF) by dual-energy x-ray absorptiometry. Visceral and subcutaneous fat areas (SFAs) were determined from computed tomography. Comparisons were made between different BMI groups and dialysis modalities.

RESULTS

No significant change was found in TBP, NI, or TBF. The obese group (BMI >30) had an increase in all mean LBM parameters with a significant increase in NI compared with normal-weight and the overweight group. This increase in NI remained significant after multivariate analysis β coefficient (0.08). PD patients had the greatest increase in TBF, with a significant increase in visceral fat (VFA:SFA ratio β coefficient = 0.23).

CONCLUSIONS

Obese patients showed preservation of TBP compared with normal- and overweight patients, suggesting that energy storage as fat mass is of value in the dialysis population.

Comparison of markers of appetite and inflammation between hemodialysis patients with and without failed renal transplants

OBJECTIVE

The survival of patients returning to hemodialysis (HD) following kidney transplant failure is unfavorable. However, the factors responsible for this poor outcome are largely unknown; chronic inflammation due to failed allograft and malnutrition may contribute to morbidity and mortality. We aim to compare the markers of appetite and malnutrition, and their relation with inflammation in HD patients with and without previous kidney transplantation.

METHODS

Fifty-six patients with failed renal allografts at least 3 months on dialysis (31 men, 25 women; mean age, 46 ± 9 years) and 77 HD patients who never underwent a transplant (43 men, 34 women; mean age, 50 ± 15 years) were included in the study. The appetite and diet assessment tool (ADAT) was used to determine the self reported appetite of patients. Serum concentrations of ghrelin, leptin, insulin like growth factor 1 (IGF-1), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and high-sensitivity C-reactive protein (hs-CRP) were measured. Associations among these variables were analyzed.

RESULTS

There were no significant differences considering age, gender or duration of renal replacement therapy between the 2 groups. The scores from Appetite and Diet Assessment Tool were significantly higher in the failed-transplant group. Serum ghrelin levels were significantly higher and serum albumin levels were significantly lower in the failed-transplant group. Serum leptin levels were similar between 2 groups. In addition, hs-CRP, IL-6, and TNF-α levels, which were used as inflammatory parameters, were significantly higher in the failed-transplant group.

CONCLUSIONS

Elevated serum ghrelin levels and inflammation may cause diminished appetite and malnutrition in patients with failed renal allografts, and higher levels of this hormone seem to be associated with inflammation caused by retained failed allografts.

Association between body condition and survival in dogs with acquired chronic kidney disease

BACKGROUND

Obesity in people with chronic kidney disease (CKD) is associated with longer survival. The purpose of this study was to determine if a relationship exists between body condition score (BCS) and survival in dogs with CKD.

HYPOTHESIS/OBJECTIVES

Higher BCS is a predictor of prolonged survival in dogs with CKD.

ANIMALS

One hundred dogs were diagnosed with CKD (International Renal Interest Society stages II, III or IV) between 2008 and 2009.

METHODS

Retrospective case review. Data regarding initial body weight and BCS, clinicopathologic values and treatments were collected from medical records and compared with survival times.

RESULTS

For dogs with BCS recorded (n = 72), 13 were underweight (BCS = 1-3; 18%), 49 were moderate (BCS = 4-6; 68%), and 10 were overweight (BCS = 7-9; 14%). For dogs with at least 2 body weights recorded (n = 77), 21 gained weight, 47 lost weight, and 9 had no change in weight. Dogs classified as underweight at the time of diagnosis (median survival = 25 days) had a significantly shorter survival time compared to that in both moderate (median survival = 190 days; P < .001) and overweight dogs (median survival = 365 days; P < .001). There was no significant difference in survival between moderate and overweight dogs (P = .95).

CONCLUSIONS AND CLINICAL IMPORTANCE

Higher BCS at the time of diagnosis was significantly associated with improved survival. Further research on the effects of body composition could enhance the management of dogs with CKD.

Palliative care in the treatment of end-stage renal failure

Palliative care begins with establishing goals of care based on estimated prognosis in end-stage renal disease (ESRD). Patients with ESRD are increasingly characterized by older age and multiple comorbid illnesses, and have a mortality rate 8 times higher than the general Medicare population. Dialysis patients are appropriate for palliative care because of their high mortality rate and high symptom burden. More patients and families are choosing not to start or withdraw dialysis for multiple reasons, particularly in patients older than 60 years. Advance directives and resuscitation directives are important in ensuring compassionate and goal-directed palliative care of ESRD patients. Drug toxicities are avoidable by using appropriate drugs at the correct doses and dosing intervals.

Interaction of time-varying albumin and phosphorus on mortality in incident dialysis patients

BACKGROUND AND OBJECTIVES

Hypoalbuminemia and hyperphosphatemia have been shown to be strong predictors of mortality in dialysis patients that might not be independent from each other. We prospectively investigated the relationship and interaction between serum albumin and phosphorus with all-cause mortality in an inception cohort of incident dialysis patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We followed 235 incident dialysis patients in a prospective single-center cohort study (INVOR study) applying a time-dependent Cox proportional hazards model using all measured laboratory values (2887 albumin and 10306 phosphorus values).

RESULTS

Eighty-two patients (35%) died during a median follow-up of 35.1 months. Albumin was inversely associated with mortality (hazard ratio [95% confidence interval]: 0.23 [0.14 to 0.36]; P < 0.001), whereas higher phosphorus concentrations showed a trend to an increasing risk for mortality (hazard ratio 1.57 [95% confidence interval 0.97 to 2.54]; P = 0.07). Importantly, we observed a significant interaction between albumin and phosphorus (P = 0.01). The lowest risk was found with concurrent low phosphorus and high albumin values, whereas risk was increased with either concurrent low phosphorus and low albumin values or high phosphorus and high albumin values.

CONCLUSIONS

In incident dialysis patients the associations of serum phosphorus and albumin concentrations with mortality are modified by each other over time. Phosphorus-lowering interventions that concomitantly can cause a fall in serum albumin level may be harmful and warrant additional studies. If confirmed, epidemiologic studies and therapeutic guidelines aiming for target values should consider this interplay.

Early start of dialysis: a critical review

In the US, patients who initiate dialysis "early" (at Modification of Diet in Renal Disease estimated GFR [eGFR]> 10 ml/min per 1.73 m(2)) account for over 50 percent of new dialysis starts. This trend to an early start is based on conventional wisdoms regarding benefits of dialytic clearance, that albumin levels are nutritional markers, and early dialytic therapy is justified to improve nutrition especially in diabetics and that waiting until low levels of eGFR (i.e., <6 ml/min per 1.73 m(2)) may be dangerous. In order to justify early dialysis treatment, the therapy must provide a morbidity, mortality, or quality of life benefit. The current review examines whether early dialysis initiation provides any of these benefits and whether the conventional wisdoms that have promoted this early dialysis trend are valid. Utilizing this information and the results of recent large observational studies and the randomized controlled Initiating Dialysis Early and Late (IDEAL) study, we suggest that dialysis initiation is justified at GFR levels of 5-9 ml/min/1.73 m(2), if accompanied by uremia symptoms or fluid management issues.

UK Renal Registry 13th Annual Report (December 2010): Chapter 8: adequacy of haemodialysis in UK adult patients in 2009: national and centre-specific analyses

BACKGROUND

Outcome in patients treated with haemodialysis (HD) is influenced by the delivered dose of dialysis. The UK Renal Association (RA) publishes Clinical Practice Guidelines which include recommendations for dialysis dose. The urea reduction ratio (URR) is a widely used measure of dialysis dose.

AIM

To determine the extent to which patients received the recommended dose of HD in the UK.

METHODS

All seventy-two UK renal centres submitted data to the UK Renal Registry (UKRR). Two groups of patients were included in the analyses: the prevalent patient population on 31st December 2009 and the incident patient population for 2009. Centres returning data on <50% of their patient population were excluded from centre-specific comparisons.

RESULTS

Data regarding URR were available from 63 renal centres in the UK. Fifty-one centres provided URR data on more than 90% of prevalent patients. The proportion of patients in the UK who met the UK Clinical Practice Guideline for URR (>65%) increased from 56% in 1998 to 85.5% in 2009. There was considerable variation between centres, with 19 centres attaining the RA clinical practice guideline in >90% of patients and 5 centres attaining the guideline in <70% of patients. The delivered HD dose (URR) was lower in patients who had just commenced dialysis treatment compared to patients who had survived longer on HD.

CONCLUSIONS

The delivered dose of HD for patients with established renal failure has increased over the last decade. Whilst the majority of UK patients achieved the target URR there was considerable variation between centres in the percentage of patients achieving the guideline.

No difference in meeting hemoglobin and albumin targets for dialyzed children with urologic disorders

Urologic disorders are the most common cause of chronic kidney disease in children. To determine whether children with urologic etiology of end-stage renal disease (ESRD) fare better than children with ESRD from other causes while on dialysis, we conducted a cross-sectional study of children <18 years receiving peritoneal and hemodialysis in the United States using data from the Centers for Medicare & Medicaid Services 2005 ESRD CPM Project. We compared baseline demographics and the study groups. In multivariate logistic regression analysis of 1,286 subjects, we assessed whether children with urologic disorders had a higher odds of meeting adult KDOQI targets for hemoglobin levels ≥11 g/dl and albumin ≥3.5 BCG/3.2 BCP g/dl. We conducted a subset analysis of 1,136 patients to examine the impact of erythropoietin on hemoglobin targets. Our results did not reveal differences in achievement of adult hemoglobin targets (adjusted OR: 1.27; p value 0.09; CI: 0.97-1.66) or in the subset analysis with erythropoietin (adjusted OR: 1.32; p value 0.06; CI: 0.98-1.78) or albumin targets (adjusted OR: 1.22; p value 0.21; CI: 0.90-1.65) in adjusted analyses. Due to our study's limitations, it is difficult to determine whether this may result from treatment prior to dialysis initiation or treatment effect of dialysis rather than underlying diagnosis.

Prehemodialysis care by dietitians and first-year mortality after initiation of hemodialysis

BACKGROUND

Since January 2002, Medicare has provided payment for medical nutrition therapy for patients with chronic kidney disease. Few patients receive dietary counseling before end-stage renal disease onset; whether such counseling is associated with improved outcomes is unknown.

STUDY DESIGN

Retrospective cohort analysis.

SETTING & PARTICIPANTS

Patients who initiated hemodialysis therapy on June 1, 2005, to May 31, 2007, in the United States for whom predialysis dietitian care was reported on the Centers for Medicare & Medicaid Services Medical Evidence Report.

PREDICTOR

Dietitian care before end-stage renal disease onset.

OUTCOME

Time to death.

MEASUREMENTS

Propensity score for dietitian care calculated using logistic regression; Cox regression analysis used to compare time to death by predialysis dietitian care overall and stratified by tertiles of propensity score, adjusting for baseline characteristics.

RESULTS

Most patients (88%) received no dietitian care; 9% received dietitian care for 12 months or less, and 3% received dietitian care for more than 12 months before dialysis therapy initiation (total N = 156,440). Predialysis dietitian care was associated independently with higher albumin and lower total cholesterol levels at dialysis therapy initiation. There was evidence of an independent association between predialysis dietitian care for longer than 12 months and decreased mortality during the first year on dialysis therapy for the second tertile of propensity score. Adjusted mortality HRs were 1.16 (95% CI, 0.44-3.09; P = 0.8), 0.81 (95% CI, 0.71-0.93; P = 0.002), and 0.93 (95% CI, 0.86-1.01; P = 0.1) in the first, second, and third tertiles of propensity score, respectively.

LIMITATIONS

Information for dietitian care was missing for 18.6% of Medical Evidence Reports and has low sensitivity; including only incident dialysis patients precluded evaluation of an association between dietitian care and chronic kidney disease progression; the observational design allowed the possibility of residual confounding.

CONCLUSIONS

Our study suggests an independent association between predialysis dietitian care for more than 12 months and lower mortality during the first year on dialysis therapy.

Dialysis time: does it matter? A reappraisal of existing literature

PURPOSE OF REVIEW

The length of time (Td) required for adequate maintenance hemodialysis therapy is perceived as a substantial patient burden. Technological advancements have allowed shortening Td over the past three decades. However, failure to detect improved outcomes with higher dialysis dose has prompted renewed interest in the potential impact of longer Td.

RECENT FINDINGS

Ongoing trials are focused on increasing the frequency of treatments, although the feasibility of having most patients agreeing to more than five treatments per week remain doubtful. Furthermore, survival was better in short daily hemodialysis with Td of 180 vs. 90 min. Within thrice weekly dialysis, several recent epidemiological studies have shown improved survival associated with Td more than 4 h. Improved outcomes for long in-center nocturnal hemodialysis (6-8 h, 3×/week), similar to what has been performed in Tassin for the last 30 years, have also been reported.

SUMMARY

Compelling rationale and recent outcome data support use of longer Td. Improved management of salt and water may be the cause for the dissociation of dialysis time and small molecule clearance. In most industrialized countries, hemodialysis care systems in place have the capacity to accommodate it. Until such time that results from prospective randomized trials are available, we believe that physicians should prescribe and exert all efforts to convince thrice weekly hemodialysis patients to accept 4 h as minimum Td.

Macrocytosis may be associated with mortality in chronic hemodialysis patients: a prospective study

BACKGROUND

Macrocytosis occurs in chronic hemodialysis (CHD) patients; however, its significance is unknown. The purpose of this study was to establish the prevalence and distribution of macrocytosis, to identify its clinical associations and to determine if macrocytosis is associated with mortality in stable, chronic hemodialysis patients.

METHODS

We conducted a single-centre prospective cohort study of 150 stable, adult CHD patients followed for nine months. Macrocytosis was defined as a mean corpuscular volume (MCV) > 97 fl. We analyzed MCV as a continuous variable, in tertiles and using a cutoff point of 102 fl.

RESULTS

The mean MCV was 99.1 ± 6.4 fl, (range 66-120 fl). MCV was normally distributed. 92 (61%) of patients had an MCV > 97 fl and 45 (30%) > 102 fl. Patients were not B12 or folate deficient in those with available data and three patients with an MCV > 102 fl had hypothyroidism. In a logistic regression analysis, an MCV > 102 fl was associated with a higher Charlson-Age Comorbidity Index (CACI) and higher ratios of darbepoetin alfa to hemoglobin (Hb), [(weekly darbepoetin alfa dose in micrograms per kg body weight / Hb in g/L)*1000]. There were 23 deaths at nine months in this study. Unadjusted MCV > 102 fl was associated with mortality (HR 3.24, 95% CI 1.42-7.39, P = 0.005). Adjusting for the CACI, an MCV > 102 fl was still associated with mortality (HR 2.47, 95% CI 1.07-5.71, P = 0.035).

CONCLUSIONS

Macrocytosis may be associated with mortality in stable, chronic hemodialysis patients. Future studies will need to be conducted to confirm this finding.

Modeled urea distribution volume and mortality in the HEMO Study

BACKGROUND AND OBJECTIVES

In the Hemodialysis (HEMO) Study, observed small decreases in achieved equilibrated Kt/V(urea) were noncausally associated with markedly increased mortality. Here we examine the association of mortality with modeled volume (V(m)), the denominator of equilibrated Kt/V(urea).

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Parameters derived from modeled urea kinetics (including V(m)) and blood pressure (BP) were obtained monthly in 1846 patients. Case mix-adjusted time-dependent Cox regressions were used to relate the relative mortality hazard at each time point to V(m) and to the change in V(m) over the preceding 6 months. Mixed effects models were used to relate V(m) to changes in intradialytic systolic BP and to other factors at each follow-up visit.

RESULTS

Mortality was associated with V(m) and change in V(m) over the preceding 6 months. The association between change in V(m) and mortality was independent of vascular access complications. In contrast, mortality was inversely associated with V calculated from anthropometric measurements (V(ant)). In case mix-adjusted analysis using V(m) as a time-dependent covariate, the association of mortality with V(m) strengthened after statistical adjustment for V(ant). After adjustment for V(ant), higher V(m) was associated with slightly smaller reductions in intradialytic systolic BP and with risk factors for mortality including recent hospitalization and reductions in serum albumin concentration and body weight.

CONCLUSIONS

An increase in V(m) is a marker for illness and mortality risk in hemodialysis patients.

The risks of high ultrafiltration rate in chronic hemodialysis: implications for patient care

As dialytic practice has evolved, hemodialysis (HD) adequacy has come to be defined in terms of small molecule clearance. A growing body of evidence suggests that fluid dynamics, specifically ultrafiltration rate (UFR), bear clinical and physiological significance and should perhaps play a more central role in titrating HD therapy. Three recent studies have shown an independent association between higher UFR and mortality. Further work is needed to determine whether this relationship represents a direct toxic effect of rapid fluid perturbations or whether this association is a consequence of confounding on the basis of large interdialytic weight gain, as each would prompt a different therapeutic response. This mounting evidence builds the case that fluid management should play a more central role in the dialytic prescription and that more individualized approaches to fluid management should be encouraged.

An evaluation of serum albumin, root caries, and other covariates in Gullah African Americans with type-2 diabetes

OBJECTIVES

Associations between dental conditions and overall health have been previously reported. Investigators have also shown significant inverse relationships between serum albumin (a general health status marker) and root caries. This relationship was explored among a study population of Gullah African Americans (who have a considerably lower level of non-African genetic admixture when compared to other African American populations) with type-2 diabetes (T2DM) and self-reported history of normal kidney function (N=280).

METHODS

Root caries indices were defined as total decayed and/or filled root surfaces. The coronal caries index [total decayed, missing, and/or filled coronal surfaces (DMFS)], level of glycemic control, total number of teeth, and other covariates were also evaluated. Logistic regression models were used to evaluate the associations between these factors and hypoalbuminemia (serum albumin concentrations <4 g/dl).

RESULTS

Serum albumin concentrations ranged 2.4-4.5 g/dl (mean=3.8, SD=0.3), with 70.4% exhibiting hypoalbuminemia. Root caries totals ranged 0-38 (mean=1.3, SD=4.5) surfaces decayed/filled, while total teeth ranged 1-28 (mean=19.4, SD=6.2). DMFS totals ranged 2-116 (mean=55.2, SD=28.0). We failed to detect significant associations for root caries; however, the final multivariable logistic regression models showed significant associations between hypoalbuminemia and total teeth [odds ratio (OR)=0.93, P=0.01], poor glycemic control (OR=2.49, P<0.01), elevated C-reactive protein (OR=1.57, P<0.01), glomerular filtration rates ≥60 (OR=0.31, P=0.03), and age (OR=0.97, P=0.03).

CONCLUSIONS

Previously reported inverse relationships between serum albumin and root caries were not evident in our study population. We propose that these null findings are because of the considerably lower level of root caries as well as other differing characteristics (including oral health status, the chronic presence of T2DM, and predominantly younger age) within our study population compared to these previously assessed groups.

The severity of acute kidney injury predicts progression to chronic kidney disease

Acute kidney injury (AKI) is associated with progression to advanced chronic kidney disease (CKD). We tested whether patients who survive AKI and are at higher risk for CKD progression can be identified during their hospital admission, thus providing opportunities to intervene. This was assessed in patients in the Department of Veterans Affairs Healthcare System hospitalized with a primary diagnosis indicating AKI (ICD9 codes 584.xx). In the exploratory phase, three multivariate prediction models for progression to stage 4 CKD were developed. In the confirmatory phase, the models were validated in 11,589 patients admitted for myocardial infarction or pneumonia during the same time frame that had RIFLE codes R, I, or F and complete data for all predictor variables. Of the 5351 patients in the AKI group, 728 entered stage 4 CKD after hospitalization. Models 1, 2, and 3 were all significant with 'c' statistics of 0.82, 0.81, and 0.77, respectively. In model validation, all three were highly significant when tested in the confirmatory patients, with moderate to large effect sizes and good predictive accuracy ('c' 0.81-0.82). Patients with AKI who required dialysis and then recovered were at especially high risk for progression to CKD. Hence, the severity of AKI is a robust predictor of progression to CKD.

Clinical review: Optimal dose of continuous renal replacement therapy in acute kidney injury

Continuous renal replacement therapy (CRRT) is the preferred treatment for acute kidney injury in intensive care units (ICUs) throughout much of the world. Despite the widespread use of CRRT, controversy and center-specific practice variation in the clinical application of CRRT continue. In particular, whereas two single-center studies have suggested survival benefit from delivery of higher-intensity CRRT to patients with acute kidney injury in the ICU, other studies have been inconsistent in their results. Now, however, two large multi-center randomized controlled trials - the Veterans Affairs/National Institutes of Health Acute Renal Failure Trial Network (ATN) study and the Randomized Evaluation of Normal versus Augmented Level (RENAL) Replacement Therapy Study - have provided level 1 evidence that effluent flow rates above 25 mL/kg per hour do not improve outcomes in patients in the ICU. In this review, we discuss the concept of dose of CRRT, its relationship with clinical outcomes, and what target optimal dose of CRRT should be pursued in light of the high-quality evidence now available.

Catheter access for hemodialysis defines higher mortality in late-presenting dialysis patients

BACKGROUND

This study explores the relationship between mortality and late presentation for dialysis, focusing on the role of catheter access for hemodialysis (HD).

METHODS

We analyzed data from a cohort of 286 patients commencing dialysis in 2000-2001. Survival and factors associated with death were analyzed by univariate and multivariate analysis. Dialysis access was considered in three groups: HD-AVF, HD-Catheter, and peritoneal dialysis (PD). Late referral (LR) was defined as first review by a nephrologist less than 90 days before dialysis.

RESULTS

One-year mortality was low at 10.1%. HD-Catheter patients were older (p < 0.001), more hypoalbuminemic (p < 0.001), more anemic (p = 0.005), and more likely to be LR (p < 0.001). HD-Catheter patients did not have significantly higher comorbidity (p = 0.128). HD-Catheter was strongly associated with late presentation (75% LR vs. 28% early referral, p < 0.001). Factors associated with death by univariate analysis included age (p < 0.0001), comorbidity (p < 0.0001), HD-Catheter (p < 0.0001), LR (p = 0.0001), hypoalbuminemia (p = 0.0011), and diabetes (p = 0.02). When corrected for these factors, HD-Catheter was associated with death (HR 2.226, 95% CI 1.314-3.772, p = 0.003) but LR was not (p = 0.38).

CONCLUSIONS

A predominant feature of LR that predicts mortality is the use of catheter access for HD. This may be modifiable in those LR patients who do not present as uremic emergencies.

The effect of resistance exercise to augment long-term benefits of intradialytic oral nutritional supplementation in chronic hemodialysis patients

BACKGROUND

Resistance exercise combined with intradialytic oral nutrition (IDON) supplementation improves net protein balance in the acute setting in chronic hemodialysis patients. We hypothesized that combination of long-term resistance exercise and IDON would improve markers of muscle mass and strength further compared with IDON alone.

METHODS

Thirty-two participants (21 male; mean age, 43 ± 13 years) on chronic hemodialysis were randomly assigned to IDON plus resistance exercise (NS + EX), or IDON (NS) alone for 6 months. IDON consisted of a lactose-free formula consisting of protein, carbohydrate, and fat. Three sets of 12 repetitions of leg-press were completed before each dialysis session in the NS + EX arm. Primary outcome measurement was lean body mass. Muscle strength and other nutritional parameters were measured as secondary outcomes.

RESULTS

Of 32 participants, 22 completed the 6-month intervention. There were no statistically significant differences between the study interventions with respect to changes in lean body mass and body weight, when comparing NS + EX to NS. There were also no statistically significant differences in any of the secondary outcomes measured in the study. Body weight (80.3 ± 16.6 kg, 81.1 ± 17.5 kg, and 80.9 ± 18.2 kg at baseline, month 3, and month 6, respectively; P = .02) and 1-repetition maximum (468 ± 148 lb, 535 ± 144 lb, and 552 ± 142 lb, respectively; P = .001) increased statistically significantly during the study for all patients combined.

CONCLUSION

This study did not show further benefits of additional resistance exercise on long-term somatic protein accretion above and beyond nutritional supplementation alone. When both treatments groups were combined, body weight and muscle strength improved during the study.

Wasting in chronic kidney disease

Wasting/cachexia is prevalent among patients with chronic kidney disease (CKD). It is to be distinguished from malnutrition, which is defined as the consequence of insufficient food intake or an improper diet. Malnutrition is characterized by hunger, which is an adaptive response, whereas anorexia is prevalent in patients with wasting/cachexia. Energy expenditure decreases as a protective mechanism in malnutrition whereas it remains inappropriately high in cachexia/wasting. In malnutrition, fat mass is preferentially lost and lean body mass and muscle mass is preserved. In cachexia/wasting, muscle is wasted and fat is relatively underutilized. Restoring adequate food intake or altering the composition of the diet reverses malnutrition. Nutrition supplementation does not totally reverse cachexia/wasting. The diagnostic criteria of cachexia/protein-energy wasting in CKD are considered. The association of wasting surrogates, such as serum albumin and prealbumin, with mortality is strong making them robust outcome predictors. At the patient level, longevity has consistently been observed in patients with CKD who have more muscle and/or fat, who report better appetite and who eat more. Although inadequate nutritional intake may contribute to wasting or cachexia, recent evidence indicates that other factors, including systemic inflammation, perturbations of appetite-controlling hormones from reduced renal clearance, aberrant neuropeptide signaling, insulin and insulin-like growth factor resistance, and metabolic acidosis, may be important in the pathogenesis of CKD-associated wasting. A number of novel therapeutic approaches, such as ghrelin agonists and melanocortin receptor antagonists are currently at the experimental level and await confirmation by randomized controlled clinical trials in patients with CKD-associated cachexia/wasting syndrome.

Urea kinetics and intermittent dialysis prescription in small animals

Hemodialysis improves survival for animals with acute kidney injury beyond what would be expected with conventional management of the same animals. Clinical evidence and experience in human patients suggest a role for earlier intervention with renal replacement to avoid the morbidity of uremia and to promote better metabolic stability and recovery. For a large population of animal patients, it is the advanced standard for the management of acute and chronic uremia, life-threatening poisoning, and fluid overload for which there is no alternative therapy.

Bone mineral density in Kuwaiti patients with end-stage renal disease

OBJECTIVE

This study compared an ethnically uniform group of end-stage renal disease (ESRD) Kuwaiti patients with a control group of healthy Kuwaiti subjects, in terms of their bone mineral density (BMD) and anthropometric measurements.

SUBJECTS AND METHODS

Included in the study were 94 males and 129 females with a mean age of 48 ± 10 years. Forty-five males and 53 females had ESRD. The remaining 49 males and 26 females were the control subjects. BMD was measured at total lumbar spine (L1-L4) and total left hip, using dual energy X-ray absorptiometry (HOLOGIC, QRS series, Europe, Belgium). The data were analyzed using SPSS, version 15 (SPSS Inc., Chicago, Ill., USA). The difference in BMD and the anthropometric measurements between the ESRD patients and the controls was assessed. Multivariate linear regression models were used to examine independent effects of ESRD on BMD while adjusting for relevant covariates.

RESULTS

The ESRD patients had a lower BMD than the controls at the hip (0.81 ± 0.11 vs. 0.92 ± 0.16) and the spine (0.84 ± 0.12 vs. 0.92 ± 0.16), p < 0.001. They also had a lower body mass index (27.80 ± 6.03 vs. 30.85 ± 6.54; p < 0.001) and were taller (162.56 ± 15.31 vs. 156.94 cm ± 10.03; p < 0.01). The reduced BMD persisted after controlling for confounding effects of sex, age and anthropometric measurements (p < 0.001).

CONCLUSION

Kuwaiti patients with ESRD had a lower BMD and, therefore, an increased risk of osteoporosis and bone fractures.

Peritoneal dialysis in cats with acute kidney injury: 22 cases (2001-2006)

BACKGROUND

Peritoneal dialysis (PD) has been described for use in animals with acute kidney injury refractory to fluid therapy. However, no study has examined the use of PD in a large group of cats.

HYPOTHESIS

PD is an important adjunctive therapy to treat acute kidney injury in cats.

ANIMALS

The medical records of 22 cats with acute kidney injury that had received PD were examined. Animals were excluded if acute uremia was a result of postrenal causes such as uroabdomen or urethral obstruction.

METHODS

Medical records were reviewed for the following: indication for PD, outcome, number of cycles performed, survival time, and predialysis and postdialysis results for blood urea nitrogen (BUN), creatinine, potassium, chloride, sodium, phosphorus, total protein, and albumin concentrations, and urine output.

RESULTS

Indications for PD include acute-on-chronic kidney injury, acute kidney injury caused by toxins, bilateral ureteroliths, bilateral ureteral ligation as a complication of ovariohysterectomy, and unknown causes. The median survival time for all cats on PD was 4 days, although the median survival time for the cats that were discharged was 774 days. The most common complications were dialysate retention and sequestration of dialysate SC. There was a significant (P < .05) decrease between predialysis and postdialysis results for BUN, creatinine, potassium, phosphorus, total protein, and albumin concentrations. There was a significant (P < .05) difference in survival times between sexes.

CONCLUSIONS AND CLINICAL IMPORTANCE

PD is an effective option for treatment of cats with acute kidney injury refractory to fluid therapy.

FHN Trial Group, Chertow GM, Levin NW, Beck GJ, Depner TA, Eggers PW, Gassman JJ, Gorodetskaya I, Greene T, James S, Larive B, Lindsay RM, Mehta RL, Miller B, Ornt DB, Rajagopalan S, Rastogi A, Rocco MV, Schiller B, Sergeyeva O, Schulman G, Ting GO, Unruh ML, Star RA, Kliger AS. In-center hemodialysis six times per week versus three times per week

BACKGROUND

In this randomized clinical trial, we aimed to determine whether increasing the frequency of in-center hemodialysis would result in beneficial changes in left ventricular mass, self-reported physical health, and other intermediate outcomes among patients undergoing maintenance hemodialysis.

METHODS

Patients were randomly assigned to undergo hemodialysis six times per week (frequent hemodialysis, 125 patients) or three times per week (conventional hemodialysis, 120 patients) for 12 months. The two coprimary composite outcomes were death or change (from baseline to 12 months) in left ventricular mass, as assessed by cardiac magnetic resonance imaging, and death or change in the physical-health composite score of the RAND 36-item health survey. Secondary outcomes included cognitive performance; self-reported depression; laboratory markers of nutrition, mineral metabolism, and anemia; blood pressure; and rates of hospitalization and of interventions related to vascular access.

RESULTS

Patients in the frequent-hemodialysis group averaged 5.2 sessions per week; the weekly standard Kt/V(urea) (the product of the urea clearance and the duration of the dialysis session normalized to the volume of distribution of urea) was significantly higher in the frequent-hemodialysis group than in the conventional-hemodialysis group (3.54±0.56 vs. 2.49±0.27). Frequent hemodialysis was associated with significant benefits with respect to both coprimary composite outcomes (hazard ratio for death or increase in left ventricular mass, 0.61; 95% confidence interval [CI], 0.46 to 0.82; hazard ratio for death or a decrease in the physical-health composite score, 0.70; 95% CI, 0.53 to 0.92). Patients randomly assigned to frequent hemodialysis were more likely to undergo interventions related to vascular access than were patients assigned to conventional hemodialysis (hazard ratio, 1.71; 95% CI, 1.08 to 2.73). Frequent hemodialysis was associated with improved control of hypertension and hyperphosphatemia. There were no significant effects of frequent hemodialysis on cognitive performance, self-reported depression, serum albumin concentration, or use of erythropoiesis-stimulating agents.

CONCLUSIONS

Frequent hemodialysis, as compared with conventional hemodialysis, was associated with favorable results with respect to the composite outcomes of death or change in left ventricular mass and death or change in a physical-health composite score but prompted more frequent interventions related to vascular access. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases and others; ClinicalTrials.gov number, NCT00264758.).

Current and potential roles of ghrelin in clinical practice

Ghrelin is a novel GH-releasing peptide, which has been identified as an endogenous ligand for GH-secretagogue receptor. Ghrelin is mainly secreted by the stomach and plays a critical role in a variety of physiological processes including endocrine, metabolic, cardiovascular, immunological, and other actions. Ghrelin stimulates food intake via hypothalamic neurons and causes a positive energy balance and body weight gain by decreasing fat utilization and promoting adiposity. Given the multiple effects of ghrelin, its potential clinical applications have been evaluated in various conditions. Preliminary trials have shown that it may prove valuable in the management of disease-induced cachexia. Ghrelin may improve the wasting syndrome through GH-dependent or GH-independent effects. Moreover, ghrelin may play a role in the management of disorders of gut motility and obesity. Finally, other potential clinical applications of ghrelin include the treatment of patients with diabetes mellitus, infections, rheumatological diseases or GH deficiency and the diagnosis of this hormonal disorder.

Low health literacy associates with increased mortality in ESRD

Limited health literacy is common in the United States and associates with poor clinical outcomes. Little is known about the effect of health literacy in patients with advanced kidney disease. In this prospective cohort study we describe the prevalence of limited health literacy and examine its association with the risk for mortality in hemodialysis patients. We enrolled 480 incident chronic hemodialysis patients from 77 dialysis clinics between 2005 and 2007 and followed them until April 2008. Measured using the Rapid Estimate of Adult Literacy in Medicine, 32% of patients had limited (<9th grade reading level) and 68% had adequate health literacy (≥9th grade reading level). Limited health literacy was more likely in patients who were male and non-white and who had fewer years of education. Compared with adequate literacy, limited health literacy associated with a higher risk for death (HR 1.54; 95% CI 1.01 to 2.36) even after adjustment for age, sex, race, and diabetes. In summary, limited health literacy is common and associates with higher mortality in chronic hemodialysis patients. Addressing health literacy may improve survival for these patients.

Comparison of patients starting hemodialysis with those underwent hemodialysis 15 years ago at the same dialysis center in Korea

BACKGROUND/AIMS

Maintenance dialysis is made decreased the death rate of patients with end-stage renal disease; however, mortality is still high. The aim of this study was to identify the association between clinical parameters at the start of hemodialysis with survival and compare these findings with data from patients who underwent hemodialysis about 15 years ago at the same dialysis center.

METHODS

We reviewed 117 patients who started hemodialysis between 2000 and 2004. We analyzed medical histories, laboratory findings, and clinical outcomes, and compared them with patients who started hemodialysis 15 years ago at the same center.

RESULTS

The proportion of elderly patients and those with diabetes increased from 17% and 18% in the previous study to 33% and 49% in this study, respectively. Elderly and patients with diabetes had much higher mortalities than their counterparts. Nevertheless, the overall survival rate (66% vs. 71% at 5 years) and survival of patients with diabetes improved (55% vs. 75% at 1.5 years). Common causes of death were infection and cardiovascular disease in the present study; however, inadequate dialysis accounted for 25% of deaths in the previous study.

CONCLUSIONS

The overall survival rate of patients undergoing hemodialysis has improved over the 15-year interval, even with an increased proportion of elderly patients and patients with diabetes. Adequate dialysis and further medical improvements could ameliorate mortality in patients undergoing dialysis.

Predictors and consequences of higher estimated glomerular filtration rate at dialysis initiation

There have been no studies in pediatric dialysis patients to evaluate the impact of higher estimated glomerular filtration rate (eGFR) at dialysis initiation on clinical outcomes. Baseline clinical and demographic information was collected for children aged 1-18 years undergoing incident dialysis from 1995-2002 within the United States Renal Data System. Baseline eGFRs calculated by the Schwartz formula were categorized as high (>15 ml/min/1.73 m(2)) or low (< or = 15 ml/min/1.73 m(2)). We determined predictors of eGFR at baseline, and associations between baseline eGFR and subsequent hospitalization for hypertension (HTN) or pulmonary edema (PE) in a longitudinal nonconcurrent pediatric end-stage renal disease (ESRD) cohort. Twenty percent of children had a high eGFR at initiation. Black children were less likely to initiate dialysis with a high eGFR [adjusted odds ratio (adjOR) 0.71, p < 0.001]. Girls were less likely to have a high eGFR at baseline (adjOR 0.71, p < 0.001). Children who received predialysis erythropoietin therapy were more likely to start dialysis with a high eGFR (adjOR 6.67, p < 0.001). Children with higher baseline eGFR were found to have a 21% decreased risk of hospitalization [adjusted hazard ratio (HR) 0.79, 95% confidence interval (CI) 0.65-0.96, p = 0.02]. It is not known whether this clinical benefit will result in decreased mortality and complication rates from cardiovascular disease.

[Impact of health insurance type on the quality of hemodialysis services: a multilevel analysis]

OBJECTIVES

This study aims to compare quality indicators for the hemodialysis services between patients with health insurance and those with medical aid.

METHODS

This study used data from sampled hospitals that provided a hemodialysis service. A total of 2,287 patients were selected, and the information for hemodialysis service has been granted from medical record reviews. A multi-level regression analysis was used to examine the differences in process and outcome indicators for hemodialysis between patients with health insurance and those with medical aid. Process indicators were defined as: frequency of hemodialysis, hemodialysis time, erythropoietin (EPO) use, measurement of hemodialysis dose at least once a month, measurement of phosphate at least once every three months, and measurement of albumin at least once every three months. Outcome indicators were defined as: hemodialysis adequacy, anemia management, blood pressure management, and calcium, phosphate and nutrition management. The total scores for outcome indicators ranged from 0 (worst) to 4 (best).

RESULTS

There was a significant difference in the measurement of hemodialysis dose at least once a month between patients with health insurance and those with medical aid (OR 0.66, 95% CI=0.43-0.99). However, frequency of hemodialysis, hemodialysis time, EPO use, measurement of phosphate at least once every three months, measurement of albumin at least once every three months, hemodialysis adequacy management, Hb >or= 11 g/dL, blood pressure within the range of 100-140/60-90 mmHg, calcium x phosphate <or= 55 g(2)/dL(2) and albumin >or= 4 g/dL were not significantly different between the groups.

CONCLUSIONS

There were no significant differences in outcome indicators for hemodialysis between the groups. Further studies are warranted into the mechanism that results in no differences in the outcome indicators for hemodialysis.