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

Growth Hormone Treatment during Hemodialysis in a Randomized Trial Improves Nutrition, Quality of Life, and Cardiovascular Risk

Nutritional markers, such as lean body mass (LBM) and serum albumin, predict outcome in dialysis patients, in whom protein-energy malnutrition is associated with increased morbidity and mortality. The metabolic effects of human growth hormone (hGH) may improve the nutritional and cardiovascular health of these patients and consequently reduce morbidity and mortality. The aim of this study was to establish clinical proof of concept of hGH treatment for the improvement of the nutritional status in adult patients who are on maintenance hemodialysis. A total of 139 adult patients who were on maintenance hemodialysis and had serum albumin levels < or =40 g/L were randomly assigned to 6 mo of treatment with placebo or 20, 35, or 50 microg/kg per d hGH. Change in LBM and serum albumin (primary outcomes), health-related quality of life, and secondary efficacy and safety parameters were monitored. The study showed that hGH treatment increased LBM significantly at all dosage levels (2.5 kg [95% confidence interval 1.8 to 3.1] versus -0.4 kg [95% confidence interval -1.4 to 0.6]; P < 0.001 for pooled hGH groups versus placebo). Serum albumin tended to increase (P = 0.076), serum transferrin (P = 0.001) and serum HDL (P < 0.038) increased, and plasma homocysteine was reduced (P = 0.029). TNF-alpha also tended to decrease with treatment (P = 0.134). An improvement in the Role Physical SF-36 quality-of-life subscale was observed (P = 0.042). There were no differences in clinically relevant adverse events between groups. In conclusion, hGH therapy safely improves LBM, other markers of mortality and morbidity, and health-related quality of life in adult patients who are on maintenance hemodialysis. A long-term study is warranted to investigate whether these treatment benefits result in reduced mortality and morbidity.

Effect of intradialytic parenteral nutrition in patients with malnutrition–inflammation complex syndrome on body weight, inflammation, serum lipids and adipocytokines: results from a pilot study

OBJECTIVE

Evaluation of the influence of intradialytic parenteral nutrition (IDPN) in patients suffering from Malnutrition-Inflammation Complex Syndrome (MICS) on nutritional status, inflammation, adipocytokines and serum lipids.

SUBJECTS

Six patients with MICS were assigned to IDPN, whereas six patients matched for age, sex, body mass index (BMI) and co-morbidity without malnutrition served as controls. Patients were recruited from Outpatient Dialysis Unit, Medical University Innsbruck and from Dialysis Unit, Hospital Feldkirch.

RESULTS

In all patients with IDPN, dry body weight increased during the interventional period whereas body weight remained stable in patients without IDPN. Tumor necrosis factor (TNF)-alpha levels were higher in patients with MICS compared with controls at all time points. Total cholesterol, LDL- and HDL-levels significantly increased during dialysis at all time points in controls but not in patients with MICS. Albumin, C-reactive protein, interleukin-6 (IL-6), soluble interleukin-2 receptor (sIL-2R) and adipocytokines did not differ between patients and controls during the study period.

CONCLUSIONS

IDPN in patients with MICS increases body weight despite not influencing inflammatory status. Furthermore, IDPN does not induce a pro-atherogenic lipid composition enhancing the risk for atherosclerosis. Thus, IDPN is a safe and effective treatment of malnutrition in patients with MICS.

Protein metabolism in glucocorticoid excess: study in Cushing's syndrome and the effect of treatment

How protein metabolism is perturbed during chronic glucocorticoid excess is poorly understood. The aims were to investigate the impact of chronic glucocorticoid excess and restoration of eucortisolemia in Cushing's syndrome (CS) on whole body protein metabolism. Eighteen subjects with CS and 18 normal subjects (NS) underwent assessment of body composition using DEXA and whole body protein turnover with a 3-h constant infusion of l-[(13)C]leucine, allowing calculation of rates of leucine appearance (leucine R(a)), leucine oxidation (L(ox)), and leucine incorporation into protein (LIP). Ten subjects with CS were restudied after restoration of eucortisolemia. Percentage FM was greater (43.9 +/- 1.6 vs. 33.8 +/- 2.4%, P = 0.002) and LBM lower (52.7 +/- 1.6 vs. 62.1 +/- 2.3%, P = 0.002) in CS. LBM was significantly correlated (r(2) > 0.44, P < 0.005) to leuceine R(a), L(ox), and LIP in both groups. After correcting for LBM, leucine R(a) (133 +/- 5 vs. 116 +/- 5 micromol/min, P = 0.02) and L(ox) (29 +/- 1 vs. 24 +/- 1 micromol/min, P = 0.01) were greater in CS. FM significantly correlated (r(2) = 0.23, P < 0.05) with leucine R(a) and LIP, but not L(ox) in CS. In multiple regression, LBM was an independent determinant of all three indexes of leucine turnover, FM of leucine R(a), and LIP and CS of L(ox). Following restoration of eucortisolemia, L(ox) was reduced (Delta-7.5 +/- 2.6 micromol/min, P = 0.02) and LIP increased (Delta+15.2 +/- 6.2 micromol/min, P = 0.04). In summary, whole body protein metabolism in CS is influenced by changes in body composition and glucocorticoid excess per se, which increases protein oxidation. Enhanced protein oxidation is a likely explanation for the reduced protein mass in CS. Successful treatment of CS reduces protein oxidation and increases protein synthesis to prevent ongoing protein loss.

Body composition and physical activity in end-stage renal disease

OBJECTIVE

The study objective was to examine the relationship between visceral and somatic protein stores and physical activity in individuals with end-stage renal disease.

DESIGN

This was a prospective single-center study.

SETTING

The study took place at the Vanderbilt University Outpatient Dialysis Unit and General Clinical Research Center.

PATIENTS

Fifty-five patients with prevalent chronic hemodialysis (CHD) were included: 33 males, 22 females, 45 African Americans, 9 Caucasians, and 1 Asian. The mean age was 47.0 +/- 1.6 years, height was 166.4 +/- 13.9 cm, and weight was 83.1 +/- 2.6 kg.

METHODS

Body composition was measured by dual-energy x-ray absorptiometry. Minute-by-minute physical activity was assessed over a 7-day period with a triaxial accelerometer. Participants were interviewed by a trained registered dietitian for two 24-hour diet recalls (one from a hemodialysis day; one from a nonhemodialysis day). Laboratory values for serum concentrations of albumin, prealbumin, C-reactive protein, and creatinine were also collected.

MAIN OUTCOME MEASURE

Predictors of somatic protein stores were the main outcome measure.

RESULTS

Serum albumin was negatively and significantly correlated with the percentage of fat mass (P = .016) and kg of fat mass (P = .044). C-reactive protein was positively and significantly correlated with body weight (P = .006), percentage of fat mass (P = .017), kg of fat mass (P = .006), and body mass index (P = .004). Physical activity and total daily protein intake were the strongest predictors of the amount of lean body mass (P = .01 and .003, respectively).

CONCLUSION

The association between somatic protein and visceral protein stores is weak in patients with CHD. Whereas increased levels of physical activity and total daily protein intake are associated with higher lean body mass in patients with CHD, higher adiposity is associated with higher C-reactive protein and lower albumin values.

The Kidney Disease: Improving Global Outcomes website: Comparison of guidelines as a tool for harmonization

Chronic kidney disease (CKD) is a worldwide public health problem with significant comorbidity and mortality. Improving quality of life and survival of CKD patients necessitates a large number of preventive and therapeutic interventions. To resolve these issues several organizations have developed guidelines, which are difficult to compare comprehensively. The Kidney Disease: Improving Global Outcomes website at http://kdigo.org compares five major guidelines. The section 'compare guidelines' covers 41 topics distributed over five major subjects: (1) general clinics; (2) hemodialysis (HD); (3) vascular access for HD; (4) peritoneal dialysis; and (5) chemistries. The tables compare guideline recommendations and the evidence levels on which they are based, with direct links to each of the guidelines. These data show that the different guideline groups tend to propose similar targets, but that nuances in the guideline statements, their rationale, and grading of evidence levels present some discrepancies, although most guidelines are based on the same literature. We conclude that there is an urgent need to harmonize existing guidelines, and for a global initiative to avoid the parallel development of conflicting guidelines on the same topics. The tables displayed on the website offer a basis for structuring this process, a procedure which has recently been initiated by a body composed of the five guideline development groups.

Mortality predictors after 10 years of dialysis: a prospective study of Japanese hemodialysis patients

BACKGROUND

This work aimed to examine the predictive value for death of various clinical variables after long-term hemodialysis (HD).

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

A total of 947 patients (597 men and 350 women, aged 21 to 93 yr) who were undergoing maintenance HD in Niigata, Japan, were stratified into two cohorts: Those with >10 yr of prior HD at study enrollment (n = 391) and those with < or =10 yr of previous therapy (n = 556). The survival of patients was examined for up to 40 mo (1999 to 2003) with the Cox proportional hazards model. Baseline clinical and dialysis data and serum biochemistries were used as independent variables. For adjustment for bias in patient selection, patient survival in either cohort was analyzed separately.

RESULTS

In patients with >10 yr of HD, high pulse pressure, cerebrovascular disease, low serum creatinine, and low Kt/V values were the mortality risk predictors, whereas for those with < or =10 yr of HD, age and cerebrovascular disease were independent risk predictors for death. Diabetes, coronary artery disease, serum albumin, and C-reactive protein were NS predictors in those with long-term HD.

CONCLUSIONS

Providing adequate dosage of dialysis and achieving a better control of pulse pressure may further improve survival in selected patients who had undergone HD for >10 yr.

Protein and energy intake in advanced chronic kidney disease: how much is too much?

Uremic wasting is strongly associated with increased risk of death and hospitalization events in patients with advanced chronic kidney disease (CKD). Recent evidence indicates that patients with advanced chronic kidney disease are prone to uremic wasting due to several factors, which include the dialysis procedure and certain comorbid conditions, especially chronic inflammation and insulin resistance or deficiency. While the catabolic effects of dialysis can be readily avoided with intradialytic nutritional supplementation, there are no established alternative strategies to avoid the catabolic consequences of comorbid conditions other than treatment of their primary etiology. To this end, there is no indication that simply increasing dietary protein and energy intake above the required levels based on level of kidney disease is beneficial in patients with advanced chronic kidney disease. However, aside from the potential adverse effects such as uremic toxin production, dietary protein and energy intake in excess of actual needs might be beneficial in maintenance dialysis patients as it may lead to weight gain over time. Clearly, the role of obesity in advanced uremia needs to be examined in detail prior to making any clinically applicable recommendations, both in terms of ''low'' and ''high'' dietary protein and energy intake.

Evidence of progressive deterioration of renal function in rats exposed to a maternal low-protein dietin utero

Intrauterine growth retardation associated with maternal undernutrition is proposed to play a significant role in the aetiology of hypertension and CHD. Animal experiments suggest that the kidney, which is extremely vulnerable to the adverse effects of growth-retarding factors, may play an important role in the prenatal programming of hypertension. Maintenance of renal haemodynamic functions following structural impairment in fetal life is proposed to require adaptations which raise systemic blood pressure and promote a more rapid progression to renal failure. Rats were fed on diets containing 180 g casein/kg (control) or 90 g casein/kg (low protein) during pregnancy. The offspring were studied in terms of blood pressure, creatinine clearance, blood urea N, plasma and urinary albumin, renal morphometry and metabolic activity at 4, 12 and 20 weeks of age. Blood pressure was elevated at all ages in the low-protein-exposed offspring, relative to control rats. Rats (4 weeks old) exposed to the low-protein diet had smaller kidneys which were shorter and wider than those of control animals. Creatinine clearance was significantly reduced in 4-week-old rats exposed to the low-protein diet. Renal morphometry and creatinine clearance at older ages were not influenced by prenatal diet. Blood urea N, urinary output and urinary albumin excretion were, however, significantly greater in low-protein-exposed rats than in control rats at 20 weeks of age. These findings are suggestive of a progressive deterioration of renal function in hypertensive rats exposed to mild maternal protein restriction during fetal life. This is consistent with the hypothesis that adaptations to maintain renal haemodynamic functions following impairment of fetal nephrogenesis result in an accelerated progression towards glomerulosclerosis and increased intrarenal pressures mediated by rising vascular resistance.

Intradialytic parenteral nutrition: comparison of olive oil versus soybean oilbasedlipid emulsions

Lipid, oxidative and inflammatory parameters are frequently altered in dialysis patients and may be worsened by intravenous lipid emulsions (ILE). We assessed the efficacy and tolerance of olive as compared with standard soybean oil-based ILE during intradialytic parenteral nutrition (IDPN). IDPN mixtures containing amino acids, glucose, and either olive oil (OO group,n17) or soybean oil-based ILE (SO group,n18) were administered in a 5-week randomized, double-blind study. On days 0 and 35, patients' nutritional status was assessed by BMI, normalized protein catabolic rate, predialytic creatinine, serum albumin and transthyretin; lipid metabolism by plasma LDL- and HDL-cholesterol, triacylglycerols, phospholipids, apo A-I, A-II, B, C-II, C-III, E and lipoprotein (a); oxidative status by α-tocopherol, retinol, selenium, glutathione peroxidase, malondialdehyde and advanced oxidized protein products; inflammatory status by serum C-reactive protein, orosomucoid, IL-2 and IL-6. No serious adverse event was observed. Significant changes were observed from day 0 to day 35 (P<0·05): nutritional criteria improved (albumin in OO; albumin, transthyretin and creatinine in SO); LDL-cholesterol, apo B, C-II, C-III and apo A-I/A-II ratio increased in both groups. HDL-cholesterol decreased in OO; apo E increased and lipoprotein (a) decreased in SO; α-tocopherol/cholesterol ratio increased in OO; malondialdehyde decreased in both groups; IL-2 increased in both groups. The between-group comparison only showed the following differences: α-tocopherol/cholesterol increased in OO; lipoprotein (a) decreased in SO. From these data, it was concluded that OO- and SO-based IDPNs similarly improved nutritional status and influenced plasma lipid, oxidative, inflammatory and immune parameters.

Brain activation in uremic anorexia

This article reviews current knowledge about mechanisms responsible for uremic events, especially those that involve the central nervous system (CNS). Anorexia is a frequent complication of the uremic syndrome that contributes to malnutrition in patients on dialysis. Uremic anorexia has been associated with many factors. Traditionally, anorexia in dialysis patients has been regarded as a sign of uremic toxicity; therefore, 2 hypotheses have been proposed: the "middle molecule" and "peak concentration" hypotheses; both of these remain unproved. Recently, our group has proposed the tryptophan-serotonin hypothesis, which is based on a disorder in the amino acid profile that may be acquired when the patient is in uremic status. It is characterized by low concentrations of large neutral and branched chain amino acids in the cerebrospinal fluid. This situation permits a high level of tryptophan transport across the blood-brain barrier and enhances the synthesis of serotonin (the final target responsible for inhibiting appetite). The role of inflammation in the genesis of anorexia-malnutrition is also emphasized. In summary, in the CNS, factors associated with uremic anorexia include high levels within the cerebrospinal fluid of proinflammatory cytokines, leptin, and free tryptophan and serotonin (hyperserotoninergic-like syndrome), along with deficiency of neural nitric oxide (nNO) and disorders in various receptors such as melanocortin receptor-4 (MC4-R). Uremic anorexia is a complex complication associated with malnutrition and high levels of morbidity and mortality. Several uremia-acquired disorders in the CNS such as high cerebrospinal fluid levels of anorexigen substances and disorders in appetite regulator receptors may explain the lack of appetite.

Association between dialysis dose improvement and nutritional status among hemodialysis patients

BACKGROUND

Several studies suggest an association between improved survival and better nutritional status. It has been suggested that there is a correlation between dose of dialysis and nutritional status. However, in spite of the current practice, there are conflicting reports regarding the relationship between dose of dialysis or malnutrition, and biochemical outcome. In this article, we will discuss the impact of dose of dialysis on nutritional status and biochemical outcome in hemodialysis patients. We will also mention the interrelationships of dialysis dose, malnutrition, and biochemical outcome with respect to these patients.

METHODS

Data were processed on 134 dialysis patients (mean age 48.21 +/- 13.38, 69 male, 65 female) on 3-times-per-week dialysis regimens. The overall study period was 3 months from June 1, 2005 to August 31, 2005. The patients were divided into two groups: the baseline group and the intervention group. The data of the baseline group were collected in June, 2005 and the data of the intervention group were collected in August, 2005 after applying the intervention or a protocol for dialysis adequacy improvement.

RESULTS

The statistical analysis demonstrated that there was a significant improvement in mean URR and Kt/V from the baseline to the intervention group. The intervention group had a considerably higher rate than the baseline group for all nutritional and biochemical outcome parameters. The study showed a strong positive correlation between nPCR and Kt/V (p = 0.0001) and also a strong positive correlation between serum albumin and Kt/V (p = 0.00001). No correlations were found between Kt/V and biochemical outcomes such as hemoglobin (p = 0.4922), calcium (p = 0.650), phosphate (p = 0.508), and phosphatase (p = 0.091).

CONCLUSION

All the available evidence in hemodialysis patients confirms the close association between dialysis dose and biochemical outcome. A body of evidence also highlights the existence of relationship between malnutrition and outcome among these patients. Dose of dialysis and nutrition are considered to be interrelated.

Severe Periodontitis Is Associated with Low Serum Albumin among Patients on Maintenance Hemodialysis Therapy

The relationship between periodontitis and two measures of systemic inflammation, serum albumin and C-reactive protein (CRP), were examined among patients who were receiving chronic outpatient hemodialysis. Adult patients at two locations, North Carolina and New York City, were evaluated by dentist examiners. Six sites per tooth (up to 32 teeth per patient) were examined. A periodontitis case was defined as > or = 60% of sites with attachment level > or = 4 mm. Multivariable logistic regression was used to determine the association of periodontitis with low serum albumin, defined as < 3.5 mg/dl, and with high CRP, defined as > 3.0 mg/dl. A total of 154 patients completed the study. The mean age was 54.6 yr (SD 13.3), and average duration of dialysis was 4.0 yr (3 mo to 16 yr). Eighty-six (54.6%) were men, and 89 (58.2%) were black. Common causes of end-stage kidney disease were hypertension (12.3%), diabetes (22.1%), glomerulonephritis (7.1%), and other (58.4%). The average number of teeth was 20.3 (SD 8.4). Thirty-five (23%) patients were periodontitis cases. Severe periodontitis was associated with low serum albumin (odds ratio 8.20; 95% confidence interval 1.61 to 41.82; P = 0.01) compared with individuals without severe periodontitis disease after adjustment for age, gender, race, diabetes, hypertension, body mass index, smoking, study site, total cholesterol, serum calcium, serum phosphorus, and normalized protein catabolic rate. There was no observed association of severe periodontitis with CRP. Investigation of the potential contribution of periodontitis to serum albumin and possibly to morbidity and mortality among patients with end-stage kidney disease seems warranted.

Attainment of clinical performance targets and improvement in clinical outcomes and resource use in hemodialysis care: a prospective cohort study

BACKGROUND

Clinical performance targets are intended to improve patient outcomes in chronic disease through quality improvement, but evidence of an association between multiple target attainment and patient outcomes in routine clinical practice is often lacking.

METHODS

In a national prospective cohort study (ESRD Quality, or EQUAL), we examined whether attainment of multiple targets in 668 incident hemodialysis patients from 74 U.S. not-for-profit dialysis clinics was associated with better outcomes. We measured whether the following accepted clinical performance targets were met at 6 months after study enrollment: albumin (> or =4.0 g/dl), hemoglobin (> or =11 g/dl), calcium-phosphate product (<55 mg2/dl2), dialysis dose (Kt/V> or =1.2), and vascular access type (fistula). Outcomes included mortality, hospital admissions, hospital days, and hospital costs.

RESULTS

Attainment of each of the five targets was associated individually with better outcomes; e.g., patients who attained the albumin target had decreased mortality [relative hazard (RH) = 0.55, 95% confidence interval (CI), 0.41-0.75], hospital admissions [incidence rate ratio (IRR) = 0.67, 95% CI, 0.62-0.73], hospital days (IRR = 0.61, 95% CI, 0.58-0.63), and hospital costs (average annual cost reduction = 3,282 dollars, P = 0.002), relative to those who did not. Increasing numbers of targets attained were also associated, in a graded fashion, with decreased mortality (P = 0.030), fewer hospital admissions and days (P < 0.001 for both), and lower costs (P = 0.029); these trends remained statistically significant for all outcomes after adjustment (P < 0.001), except cost, which was marginally significant (P = 0.052).

CONCLUSION

Attainment of more clinical performance targets, regardless of which targets, was strongly associated with decreased mortality, hospital admissions, and resource use in hemodialysis patients.

Association between serum lipids and survival in hemodialysis patients and impact of race

Despite the enormous cardiovascular disease epidemic among maintenance hemodialysis (MHD) patients, total hypercholesterolemia seems paradoxically to be associated with better survival. It was hypothesized that similar paradoxic associations also exist for serum LDL, HDL, and triglycerides. A 3-yr (July 2001 through June 2004) cohort of 15,859 MHD patients was studied in the United States from DaVita dialysis clinics where lipid profile was measured in at least 50% of all outpatients during a given calendar quarter. Cox proportional hazard models were adjusted for case mix and surrogates of malnutrition-inflammation complex. Both total and LDL hypercholesterolemia showed a paradoxic association with better survival. Hypertriglyceridemia (>200 mg/dl) also showed a similar trend, but serum HDL cholesterol did not have any clear association with survival. The association between a low serum LDL <70 mg/dl, which was prevalent among almost 50% of all MHD patients, and a higher all-cause death risk was robust to multivariate adjustment. In the subgroup analyses, these paradoxic associations persisted among most subgroups, although they tended to be stronger among hypoalbuminemic (<3.8 mg/dl) patients and those with a lower dietary protein intake (<1 g/kg per d). However, in black patients, a high serum LDL (>100 mg/ml) was associated with adjusted cardiovascular death hazard ratio of 1.94 (95% confidence interval 1.12 to 2.38; P = 0.02). Despite inverse associations between hyperlipidemia and survival, black MHD patients with high LDL show almost two-fold increase in cardiovascular death risk. Although these associations may not be causal, they call into question whether specific subgroups of dialysis patients are better targets for cholesterol-lowering therapy.

Relationship between P-wave dispersion and effective hemodialysis in chronic hemodialysis patients

OBJECTIVE

To investigate whether or not P-wave dispersion (PWD) can be used as a good indicator of effective hemodialysis.

SUBJECTS AND METHODS

The study included 35 patients (20 males, 15 females, mean age 61 +/- 10 years) who regularly received hemodialysis treatment for chronic renal failure. Following hemodialysis, the patients whose hemodynamic parameters were preserved and who reached dry body weight were included. Twelve-lead resting electrocardiogram (ECG) at a speed of 25-50 mm/s, the value of total body fluid (TBF) and bioelectric impedance using bipedal bioelectric impedance equipment were obtained before and immediately after hemodialysis. Blood samples were also taken for the assessment of blood electrolytes, urea and creatinine. PWD was defined as the difference between the maximum and minimum P-wave duration calculated on a standard 12-lead ECG before and after dialysis.

RESULTS

The following parameters were obtained before and after hemodialysis: blood pressure 132 +/- 21 vs. 130 +/- 10 mm Hg (p > 0.05), TBF 33.9 +/- 6 vs. 32 +/- 5.6 liters (p = 0.001), impedance 499 +/- 110 vs. 596 +/- 136 Omega (p = 0.001), P-max 103.1 +/- 8.9 vs. 106.3 +/- 12.7 ms (p > 0.05), P-min 70.2 +/- 11 vs. 72.5 +/- 7.9 ms (p > 0.05), PWD 32.2 +/- 11.9 vs. 33.8 +/- 13.4 ms (p > 0.05). Although statistically significant decreases were observed in urea and creatinine levels after hemodialysis, no such changes were observed in blood electrolytes.

CONCLUSION

The P-max and PWD did not change significantly after hemodialysis, hence these two parameters can be used as an indicator of effective hemodialysis.

Can a decreasing ultrafiltration profile affect the dialytic dose administered?

During hemodialysis, ultrafiltration (UF) seems to affect the dialytic dose because of convective removal of urea and contraction of its distribution volume. We aimed to assess whether the adoption of a decreasing UF profile could yield a different dialytic dose from that obtained with a constant UF mode. Ten patients were randomly assigned to undergo 12 sessions with a constant UF mode (phase A) followed by 12 sessions with a decreasing UF rate (phase B), or the reverse. Kt/V and urea reduction ratio (URR) were 1.77 +/- 0.26 and 70.02 +/- 8.26% in phase A vs. 1.81 +/- 0.36 and 71.02 +/- 6.48% in phase B, respectively, showing no significant difference. Measurement of the differences in volemic variations between the two phases showed a statistically significant difference at the second hour (P < 0.001, the volemic reduction being greater in phase B than A) and at the fourth hour (P < 0.001, being greater in phase A than B). In standard bicarbonate dialysis, the adoption of a decreasing UF profile rather than a constant one does not alter the efficiency of the dialytic treatment.

Associations between CMS's Clinical Performance Measures project benchmarks, profit structure, and mortality in dialysis units

Prior studies observing greater mortality in for-profit dialysis units have not captured information about benchmarks of care. This study was undertaken to examine the association between profit status and mortality while achieving benchmarks. Utilizing data from the US Renal Data System and the Centers for Medicare & Medicaid Services' end-stage renal disease (ESRD) Clinical Performance Measures project, hemodialysis units were categorized as for-profit or not-for-profit. Associations with mortality at 1 year were estimated using Cox regression. Two thousand six hundred and eighty-five dialysis units (31,515 patients) were designated as for-profit and 1018 (15,085 patients) as not-for-profit. Patients in for-profit facilities were more likely to be older, black, female, diabetic, and have higher urea reduction ratio (URR), hematocrit, serum albumin, and transferrin saturation. Patients (19.4 and 18.6%) in for-profit and not-for-profit units died, respectively. In unadjusted analyses, profit status was not associated with mortality (hazard ratio (HR)=1.04, P=0.09). When added to models with profit status, the following resulted in a significant association between profit status (for-profit vs not-for-profit) and increasing mortality risk: URR, hematocrit, albumin, and ESRD Network. In adjusted models, patients in for-profit facilities had a greater death risk (HR 1.09, P=0.004). More patients in for-profit units met clinical benchmarks. Survival among patients in for-profit units was similar to not-for-profit units. This suggests that in the contemporary era, interventions in for-profit dialysis units have not impaired their ability to deliver performance benchmarks and do not affect survival.

Continuous online monitoring of ionic dialysance allows modification of delivered hemodialysis treatment time

Considerable intrinsic intrapatient variability influences the actual delivery of Kt/V. The aim of this study is to examine the feasibility of using continuous online assessment of ionic dialysance measurements (Kt/V(ID)) to allow dialysis sessions to be altered on an individual basis. Ten well-established chronic hemodialysis (HD) patients without significant residual renal function were studied (mean age 65+/-4.3 [38-81] years, mean length of time on dialysis 66+/-18 [14-189] months). These patients had all been receiving thrice-weekly 4-hr dialysis using Integra dialysis monitors. Dialysis monitors were equipped with Diascan modules permitting measurement of Kt/V(ID). Predicted treatment time required to achieve a Kt/V(ID) > or = 1.1 (equivalent to a urea-based method of 1.2) was calculated from the delivered Kt/V(ID) at 60 and 120 min. Treatment time was reprogrammed at 2 hr (ensuring all planned ultrafiltration would be accommodated into the new modified session duration). Owing to practical issues, and to avoid excessively short dialysis times, these changes were censored at no more than+/-10% of the usual 240-min treatment time (210-265 min). Data were collected from a total of 50 dialysis sessions. Almost all sessions (47/50) required modification of the standard treatment time: 13/50 sessions were lengthened and 34/50 shortened (mean length of session 232.2+/-2.5 [210-265] min). A Kt/V(ID) of > or = 1.1 was achieved in 39/50 sessions. The difference in mean urea-based Kt/V poststudy (1.3+/-0.05 [1.1-1.6]) and mean achieved Kt/V(ID) (1.16+/-0.02 [0.7-1.37]) was significant (p = 0.002). The use of individualized variable dialysis treatment time using online ionic dialysance measurements of Kt/V(ID) appears both practicable and effective at ensuring consistently delivered adequate dialysis.

The kidney disease wasting: inflammation, oxidative stress, and diet-gene interaction

The 350,000 maintenance hemodialysis (MHD) patients in the United States have an unacceptably high mortality rate of >20%/year. Almost half of all deaths are assumed to be cardiovascular. Markers of kidney disease wasting (KDW) such as hypoalbuminemia, anorexia, body weight and fat loss, rather than traditional cardiovascular risk factors, appear to be the strongest predictors of early death in these patients. The KDW is closely related to oxidative stress (SOX). Such SOX markers as serum myeloperoxidase are associated with pro-inflammatory cytokines and poor survival in MHD patients. Identifying the conditions that modulate the KDW/SOX-axis may be the key to improving outcomes in MHD patients. Dysfunctional lipoproteins such as a higher ratio of the high-density lipoprotein inflammatory index (HII) may engender or aggravate the KDW, whereas functionally intact or larger lipoprotein pools, as in hypercholesterolemia and obesity, may mitigate the KDW in MHD patients. Hence, a reverse epidemiology or "bad-gone-good" phenomenon may be observed. Diet and gene and their complex interaction may lead to higher proportions of pro-inflammatory or oxidative lipoproteins such as HII, resulting in the aggravation of the SOX and inflammatory processes, endothelial dysfunction, and subsequent atherosclerotic cardiovascular disease and death in MHD patients. Understanding the factors that modulate the KDW/SOX complex and their associations with genetic polymorphism, nutrition, and outcomes in MHD patients may lead to developing more effective strategies to improve outcomes in this and the 20 to 30 million Americans with chronic disease states such as individuals with chronic heart failure, advanced age, malignancies, AIDS, or cachexia.

Advanced glycation end products in renal failure

Cellular and extracellular proteins suffer significant damage in vivo by glycation. Physiological proteolysis of proteins damaged by glycation forms glycation free adducts that are released into plasma for urinary excretion. Inefficient elimination of these free adducts in uremia leads to their accumulation. In mild renal insufficiency, plasma glycation free adducts accumulated as renal clearance declined. In patients with end-stage renal disease, plasma glycation free adducts were increased up to 18-fold on peritoneal dialysis and up to 40-fold on hemodialysis. Glycation free adduct concentrations in peritoneal dialysate increased with dialysate dwell time, achieving concentrations in the dialysate higher than in plasma--suggesting that glycation adduct formation may occur in the peritoneal cavity and active transport into the peritoneal cavity may occur. In hemodialysis, plasma glycation free adducts equilibrated rapidly across the dialysis membrane, with both plasma and dialysate concentrations decreasing during a dialysis session. Therefore, protein glycation free adducts normally excreted efficiently in urine show profound mishandling and accumulation in chronic renal failure. Their accumulation may impair vascular cell function and contribute to morbidity and mortality in renal disease.

Association of mortality and hospitalization with achievement of adult hemoglobin targets in adolescents maintained on hemodialysis

With the use of data from the Centers for Medicare & Medicaid Services' ESRD Clinical Performance Measures Project (October through December 1999 and 2000) linked with US Renal Data System hospitalization and mortality records, whether achieving adult target hemoglobin (Hb) levels in adolescents who are on hemodialysis (HD) was associated with decreased risk for death or hospitalization was assessed. Of 677 adolescents, 238 were hospitalized and 54 died. In bivariate analysis, 11.7% with Hb <11 g/dl at study entry died versus 5% of those with initial Hb > or =11 g/dl (P = 0.001); 40.3% with baseline Hb <11 g/dl were hospitalized versus 31.1% with initial Hb > or =11 g/dl (P = 0.013). In multivariate analysis, Hb > or =11 g/dl was associated with decreased risk for death (hazard ratio [HR] 0.38; 95% confidence interval [CI] 0.20 to 0.72) but did not show a statistically significant association with decreased risk for hospitalization (HR 0.87; 95% CI 0.66 to 1.15). When Hb was recategorized as Hb <10, > or =10 and <11, > or =11 and < or =12, and >12 g/dl, risk of mortality declined as Hb level increased. At Hb 11 to 12 g/dl (versus Hb <10 g/dl), mortality risk decreased by 69% (HR 0.31; 95% CI 0.14 to 0.65). Risk for mortality was similar for Hb 11 to 12 and >12 g/dl. For hospitalization, no statistically significant difference in risk between Hb categories was found. This observational study of adolescents who are on HD is consistent with adult literature showing decreased mortality in patients who have ESRD and meet adult Hb targets. Further studies in the form of randomized, clinical trials are needed to assess optimal Hb levels for adolescents who are on HD.

Up-regulation of NPY gene expression in hypothalamus of rats with experimental chronic renal failure

Anorexia is possibly one of the most important causes of malnutrition in uremic patients. The cause of this abnormality is still unknown. Considering that: (a) NPY is one of the most important stimulants of food intake; (b) eating is a central nervous system regulated process and (c) NPY is expressed in hypothalamus, we hypothesized that the decrease of NPY gene expression in the hypothalamus could be an important factor contributing to anorexia associated with uremic state. In contrast to the prediction, the results presented in this paper indicate that the NPY gene expression in the hypothalamus of chronic renal failure (CRF) rats was significantly higher than in the hypothalamus of control (pair-fed) rats. Moreover, we found that serum NPY concentration in CRF rats was higher than in control (pair-fed) animals. The increase of plasma NPY concentration in CRF rats may be due to the greater synthesis of the neuropeptide in liver, since higher level of NPY mRNA was found in liver of CRF rats. The results obtained revealed that experimental chronic renal failure is associated with the increase of NPY gene expression in hypothalamus and liver of rats.

Longitudinal associations between dietary protein intake and survival in hemodialysis patients

BACKGROUND

Decreased dietary protein intake may be associated with increased mortality risk in individuals with kidney failure undergoing maintenance hemodialysis (MHD). We hypothesized that longitudinal changes in dietary protein intake have independent associations with survival in MHD patients.

METHODS

The relation between urea kinetic-based normalized protein nitrogen appearance (nPNA) and all-cause and cardiovascular mortality was examined in a 2-year (July 2001 to June 2003) cohort of 53,933 MHD patients from virtually all DaVita dialysis clinics in the United States, using both conventional and time-dependent (repeated-measure) Cox models to estimate death hazard ratios for quarterly averaged nPNA categories controlled for case-mix, comorbidity, dialysis dose (Kt/V), and available markers of malnutrition-inflammation complex syndrome (MICS).

RESULTS

The best survival was associated with nPNA between 1.0 and 1.4 g/kg/d, whereas nPNA less than 0.8 or greater than 1.4 g/kg/d was associated with greater mortality in almost all models. Adjustment for MICS mitigated the associations substantially. A decrease in protein intake during the first 6 months in patients with an nPNA in the 0.8- to 1.2-g/kg/d range was associated incrementally with greater death risks in the subsequent 18 months, whereas an increase in nPNA tended to correlate with reduced death risk.

CONCLUSION

Low daily protein intake or decrease in its magnitude over time is associated with increased risk for death in MHD patients. Whether the association between time-varying protein intake and survival is causal or a consequence of anorexia secondary to MICS or other factors needs to be explored further in interventional trials.

The tortoise and hare on hemodialysis: Does slow and steady win the race?

The importance of hemodialysis session length relative to small solute (e.g., urea) clearance has been debated for many years. Longer session length augments clearance of larger molecules and may facilitate ultrafiltration; however, the independent effects of session length on survival and other outcomes are unknown. In this report, we review two recently published observational studies examining the association between hemodialysis session length and survival. Prospective clinical trials will be required to resolve the debate.

Improving Albumin Levels Among Hemodialysis Patients: A Community-Based Randomized Controlled Trial

BACKGROUND

Low albumin level is a strong predictor of mortality and morbidity among hemodialysis patients, yet few interventions are available to improve albumin levels. Moreover, the relative importance of nutritional barriers versus inflammation in contributing to hypoalbuminemia is unclear. We sought to determine whether targeting specific nutritional barriers will improve albumin levels.

METHODS

We conducted a randomized controlled trial involving 180 patients with baseline albumin levels less than 3.7 g/dL (<37 g/L) at 44 long-term hemodialysis facilities. Study coordinators identified and intervened on specific barriers present among intervention patients, whereas control patients continued to receive the usual care. Barriers targeted included poor nutritional knowledge, poor appetite, help needed with shopping or cooking, low fluid intake, inadequate dialysis dose, depression, difficulty chewing, difficulty swallowing, gastrointestinal symptoms, and acidosis.

RESULTS

At baseline, intervention and control patients had similar albumin levels, dietary intakes, levels of inflammatory markers, and numbers of nutritional barriers. After 12 months, intervention patients had greater increases in albumin levels compared with control patients (+0.21 versus +0.06 g/dL [+2.1 versus +0.6 g/L]; P < 0.01), as well as greater increases in energy intake (+4.1 versus -0.6 Kcal/d/kg; P < 0.001) and protein intake (+0.13 versus -0.06 g/d/kg; P < 0.001). The intervention appeared most effective for barriers related to poor nutritional knowledge, help needed with shopping or cooking, and difficulty swallowing. About half the subjects had elevated levels of inflammatory markers, but there was no relationship between change in levels of albumin and inflammatory markers.

CONCLUSION

A nutrition intervention tailored to patient-specific barriers resulted in modest improvements in albumin levels regardless of levels of inflammatory markers.

Determinants of small solute clearance in hemodialysis

Recent outcome trials in chronic dialysis patients raise concerns about the relationship between delivered urea Kt/V and survival. Nevertheless, measurement of delivered small solute clearance remains the most common approach to quantify therapy. The purpose of this review is to provide an overview of the numerous factors influencing small solute clearance during hemodialysis. Although the focus of the review is on the manner in which dialyzer characteristics influence small solute clearances, factors related to other aspects of the extracorporeal circuit and to the patient will also be discussed.

The predictive value of self-report scales compared with physician diagnosis of depression in hemodialysis patients

The prevalence of depression in end-stage renal disease (ESRD) patients on hemodialysis has not been definitively determined. We examined the prevalence of depression and the sensitivity, specificity, positive, and negative likelihood ratios (+LR and -LR) of self-report scales using the physician-administered Structured Clinical Interview for Depression (SCID) as the comparison. Ninety-eight consecutive patients completed the Beck Depression Inventory (BDI) and the Center for Epidemiological Study of Depression (CESD) scales. A physician blinded to BDI and CESD scores administered the SCID. Receiver/responder operating characteristic curves determined the best BDI and CESD cutoffs for depression. Depressed patients had more co-morbidities and lower quality of life, P<0.05. The prevalence of depression by SCID was 26.5% and of major depression was 17.3%. The CESD cutoff with the best diagnostic accuracy was 18, with sensitivity 69% (95% confidence interval (CI) (51%, 87%)), specificity 83% (95% CI (74%, 92%)), positive predictive value (PPV) 60%, negative predictive value (NPV) 88%, +LR 4.14, and -LR 0.37. The best BDI cutoff was 14, with sensitivity 62% (95% CI (43%, 81%)), specificity 81% (95% CI (72%, 90%)), PPV 53%, NPV 85%, +LR 3.26, and -LR 0.47. Self-report scales have high +LR but low -LR for diagnosis of depression. When used for screening, the threshold for depression should be higher for ESRD compared with non-ESRD patients. Identifying depression using physician interview is important, given the low -LR of self-report scales.

An anti-inflammatory and antioxidant nutritional supplement for hypoalbuminemic hemodialysis patients: a pilot/feasibility study

BACKGROUND

A low serum albumin concentration < 3.8 g/dL, a marker of malnutrition-inflammation complex syndrome, is observed in approximately half of all maintenance hemodialysis (MHD) patients in the United States and is strongly associated with increased mortality.

OBJECTIVES

We hypothesized that a novel oral nutritional intervention with anti-inflammatory and antioxidant properties taken during routine dialysis sessions is well tolerated and corrects hypoalbuminemia in MHD patients.

DESIGN

Controlled clinical study.

SETTING

An outpatient dialysis facility affiliated with a tertiary care community medical center with six equally distributed hemodialysis shifts and 163 MHD patients.

PATIENTS

Among all MHD outpatients of three selected HD shifts (n = 81 patients), 21 subjects had a serum albumin level < 3.8 g/dL. One patient who was hospitalized before the intervention was excluded. The other three dialysis shifts, with 82 MHD outpatients including 20 hypoalbuminemic subjects, were observed as concurrent controls.

INTERVENTION

The nutritional intervention included one can of Oxepa and one can of Nepro to be taken together orally during each routine hemodialysis session for 4 weeks. Each can contains 237 mL fluid. Oxepa provides 355 calories and 14.8 g protein per can, includes maltodextrin, medium-chain triglycerides, borage oil, and refined and deodorized fish oil, and is designed for critically ill patients with inflammation and oxidative stress. Each can of Oxepa includes 1,020 mg gamma-linolenic acid, 3,100 mg caprylic acid, 1,080 mg eicosapentaenoic acid, 75 mg taurine, 2,840 IU vitamin A activity, 75 IU vitamin E, and 200 mg vitamin C. Nepro provides 475 calories and 16.7 g protein per can; includes high-oleic safflower oil, corn syrup solids, and fructo-oligosaccharides; and is tailored for the nutritional needs of MHD patients. Oxepa and Nepro also contain L-carnitine, 43 mg and 62 mg, respectively.

MAIN OUTCOME MEASURES

Serum albumin pretrial and posttrial.

RESULTS

Studied outpatients (12 men and 8 women) were aged 60.4 +/- 13.0 (SD) years. Three patients had started MHD treatment between 1.5 and 3 months before the intervention. Nine patients were diabetic. Preintervention serum albumin, 3.44 +/- 0.34 g/dL (mean +/- SD) increased to 3.68 +/- 0.34 g/dL (P = .001) 4 weeks after the start of the intervention. In 16 patients, serum albumin level increased by 0.2 to 1.3 g/dL, whereas in 4 patients the serum albumin level decreased by 0.2 to 0.6 g/dL. Three patients reported diarrhea, and one diabetic patient had increased serum glucose values. No other side effects were noted. In 20 control outpatients not receiving nutritional intervention, serum albumin did not change from 3.46 +/- 0.20 to 3.47 +/- 10.44 g/dL (P = .47).

CONCLUSIONS

In hypoalbuminemic MHD patients, a short-term in-center nutritional intervention with one can of Nepro and one can of Oxepa during HD is practical, convenient, well-tolerated, and associated with a significant increase in serum albumin level. Well-designed randomized placebo-controlled clinical trials are needed to verify the safety and effectiveness of this nutritional intervention and its impact on clinical outcome in hypoalbuminemic MHD patients.

Early changes in bioelectrical estimates of body composition in chronic kidney disease

The aim of this study was to detect the potential occurrence of early abnormalities of body composition in patients with chronic kidney disease (CKD) at first referral to an outpatient nephrology clinic. Eighty-four patients with CKD (49 men and 35 women) were compared with 604 healthy control subjects (298 men and 306 women). Anthropometry and bioelectrical impedance analysis (BIA) were performed in all participants, whereas renal function, laboratory tests for nutritional status, and nutrient intake were assessed in the CKD group only. Creatinine clearance was 27.8 +/- 13.8 and 27.4 +/- 13.0 ml/min per 1.73 m(2) in male and female patients with CKD, respectively. No patient showed peripheral edema; frank malnutrition, defined by presence of serum albumin <3.5 g/dl plus body mass index <20 kg/m(2); or protein intake <0.6 g/kg per d. At the BIA, patients with CKD showed lower resistance (R) and abnormal mean impedance vectors for the bivariate normal distribution of R/height and reactance/height. Phase angle also was reduced (-22%), especially in patients with diabetes. When BIA-derived data were considered, total body water was slightly higher (+4.3% in men; +3.5% in women) and body cell mass was lower (-6.7% in men; -7.7% in women) in patients with CKD. No difference in either BIA parameters or nutritional indexes was observed among various CKD stages. Despite the absence of overt malnutrition, patients with CKD exhibit altered BIA variables from the early phases of renal disease. These alterations are related to the renal dysfunction, are more marked in the presence of diabetes, and mainly indicate the presence of overhydration in the absence of edema. Therefore, BIA represents an attractive clinical tool to detect impairment of body composition from the early stages of CKD.

Characterization of the metabolic phenotypes of Cushing's syndrome and growth hormone deficiency: a study of body composition and energy metabolism

OBJECTIVE

A comparison of the severity and distribution of perturbations in body composition and their relationship to energy metabolism in glucocorticoid excess and GH deficiency (GHD) has not been undertaken before. The aim of this study was to investigate the impact of Cushing's syndrome (CS) and GHD on whole and regional body composition and energy metabolism.

DESIGN

Cross-sectional study design.

PATIENTS

Eighteen subjects with CS (12 women, aged = 41.5 +/- 3.0 years, 24-h urinary free cortisol = 1601 +/- 361 nmol/day, normal < 300 nmol/day), 22 subjects with GHD (14 women, age = 42.9 +/- 2.9 years) and 18 normal subjects (11 women, age = 46.8 +/- 2.8 years).

MEASUREMENTS

Lean body mass (LBM), fat mass (FM) and regional body composition were assessed by dual-energy X-ray absorptiometry (DEXA). Resting energy expenditure (REE) and fat oxidation (Fox) were assessed by indirect calorimetry.

RESULTS

Mean percentage FM was significantly greater by 30% in CS (P = 0.002) and 22% in GH-deficient subjects (P = 0.014) than in normal subjects. LBM was significantly lower by 15% in CS (P = 0.002) and 11% in GHD (P = 0.013). In CS, the proportion of lean tissue in the limbs was 12% less than in normal (P = 0.001) and GH-deficient subjects (P = 0.0005). Truncal fat represented a greater proportion of total FM in CS (52.5 +/- 1.8%vs. 46.9 +/- 1.3%, P = 0.014) than in normal subjects, but not in GHD. REE and Fox, corrected for LBM, were significantly lower in GHD (P < 0.02 for both vs. normal) but not in CS.

CONCLUSION

FM was higher and LBM lower in both CS and GHD. However, there is a greater abnormality of regional body composition in patients with CS who exhibit a lower limb lean mass and a greater truncal fat. Reduced REE and Fox contribute to increased adiposity in GHD. As REE and Fox are not perturbed in CS, other mechanisms must explain the marked gain in truncal and total fat.

Changes in physical and psychosocial functioning among adolescents with chronic kidney disease

Little research has been published assessing changes in the functional health status of children and adolescents with chronic kidney disease (CKD). We know little about which clinical parameters influence functional status or health-related quality of life in these young people. In a prospective study using data from semi-annual visits over a 4-year period from 78 adolescents with CKD aged 11 years to 18 years, we detail the impact of several clinical measures (i.e., kidney function, albumin, hematocrit, height) on short-term changes in health-related quality of life. The 50-item Child Health Questionnaire Parent Form, a validated health-related quality of life measure in children, was used to obtain physical and psychosocial functioning summary scores at each visit. After adjustment for the variables mentioned above, the physical summary score on the Child Health Questionnaire (CHQ) declined as glomerular filtration rate declined. Increasing height was associated with a positive change in physical and psychosocial summary scores. We conclude that decline in kidney function is associated with a subsequent decline in health-related quality of life, particularly in terms of physical activity.

Effect of Change in Vascular Access on Patient Mortality in Hemodialysis Patients

BACKGROUND

Hemodialysis patients using a catheter have a greater mortality risk than those using an arteriovenous (AV) access (fistula or graft). However, catheter-dependent patients also differ from those with an AV access in several clinical features, and these differences may themselves contribute to their excess mortality.

METHODS

The current study evaluates whether a change in vascular access affects risk for mortality in patients enrolled in the Hemodialysis Study. Time-dependent Cox regression was used to relate mortality risk to current type of access and change in access type during the preceding 1 year.

RESULTS

Compared with patients who dialyzed using an AV access at both the beginning and end of the preceding 1-year interval, relative risks for mortality were 3.43 (95% confidence interval [CI], 2.42 to 4.86) in patients who dialyzed with a catheter at both times; 2.38 (95% CI, 1.76 to 3.23) in patients switching from an AV access to a catheter, and 1.37 (95% CI, 0.81 to 2.32) in patients switching from a catheter to an AV access. Change from AV access to a catheter was associated with an antecedent decrease in serum albumin level (odds ratio, 1.25; 95% CI, 1.09 to 1.45 per 0.5 g/dL; P = 0.002), weight loss (odds ratio, 1.14; 95% CI, 1.06 to 1.22 per 2 kg; P < 0.001), and decreases in equilibrated normalized protein catabolic rate (odds ratio, 2.22; 95% CI, 1.41 to 3.57 per 0.25 g/kg/d; P < 0.001) and non-access-related hospitalization (odds ratio, 1.19; 95% CI, 1.06 to 1.32 per 1 additional hospitalization over 4 months; P = 0.002). Change from a catheter to AV access was predicted by only the antecedent non-access-related hospitalization rate (odds ratio, 0.93; 95% CI, 0.87 to 0.97 per 1 additional hospitalization over 4 months; P < 0.001).

CONCLUSION

Change from a catheter to AV access is associated with a substantial decrease in mortality risk.

Nutrition and Metabolism in Kidney Disease

Nutritional and metabolic derangements are highly prevalent in patients with chronic kidney disease (CKD) and patients on renal replacement therapy. These derangements, which can be termed uremic malnutrition, significantly affect the high morbidity and mortality rates observed in this patient population. Uremic malnutrition clearly is related to multiple factors encountered during the predialysis stage and during chronic dialysis therapy. Several preliminary studies suggested that interventions to improve the nutritional status and metabolic status of uremic patients actually may improve the expected outcome in these patients, although their long-term efficacy is not well established. It therefore is important to emphasize that uremic malnutrition is a major comorbid condition in CKD and renal replacement therapy patients, and that all efforts should be made to try to understand better and treat these conditions effectively to improve not only mortality but also the quality of life of chronically uremic patients. In this article we review the current state of knowledge in the field of nutrition and metabolism in all stages of CKD and renal replacement therapy, including kidney transplant. We also address questions that face investigators in this field and suggest where future research might be headed.

Relationship between serum albumin level before initiating haemodialysis and angiographic severity of coronary atherosclerosis in end-stage renal disease patients

BACKGROUND

In patients with chronic kidney disease (CKD), although strong associations have been observed between malnutrition and atherosclerosis, the relationship between serum albumin concentration and angiographic changes of coronary artery disease (CAD) remains poorly explored. The goal of the present study was, in patients with CKD, to clarify the relationship between the angiographic severity of CAD and serum albumin concentration reflecting either inflammation or nutrition or both.

METHODS

In this study, 100 end-stage renal disease (ESRD) patients were enrolled, who commenced long-term dialysis therapy at our hospital and underwent coronary angiography within 3 months of the first haemodialysis (HD) session. Mean age was 63+/-11 years, 20% of the subjects were female and 62% had diabetes. Severity of CAD was evaluated in terms of (i) number of vessels exhibiting CAD (>or=75% stenosis) and (ii) Gensini score (GS). Clinical characteristics and laboratory findings were recorded at initiation of long-term HD therapy. We then evaluated a possible association with the presence and degree of CAD.

RESULTS

Sixty-four patients exhibited signs of CAD. Forty-one among them (64%) had multivessel disease. On univariate logistic regression analysis, age, diabetes and hypoalbuminaemia were significantly associated with multivessel CAD. Univariate linear regression analysis demonstrated a positive correlation of age and diabetes with GS, and an inverse correlation of BMI and serum albumin level with GS. Stepwise regression analysis showed age and serum albumin level to be independently associated with multivessel CAD and GS. The ROC curves demonstrated best cut-off levels of age and albumin for predicting multivessel CAD to be 70 years and 3.15 g/dl, respectively.

CONCLUSION

Hypoalbuminaemia at the initiation of dialysis is an important predictor of advanced CAD, particularly in male and in diabetic patients. It may reflect mainly a state of inflammation. However, malnutrition as a confounding factor cannot be entirely excluded.

Reduction in urea distribution volume over time in clinically stable dialysis patients

We have previously shown that, assuming urea distribution volume (V) remains constant for 1 month, ionic dialysance (ID) allows the dialysis dose to be calculated without the need for blood sampling. The aim of this multicenter study was to verify whether the assumption of a constant V can be extended to 1 year. In clinically stable patients receiving thrice-weekly hemodialysis at 13 dialysis centers, V and Kt/V were assessed during three dialysis sessions at baseline and 1 year later using ID as dialyzer urea clearance and the single-pool urea kinetic model. Baseline albumin, hemoglobin, and C reactive protein were prespecified covariates for predicting the change in V over time. Of the 52 enrolled patients, 40 (25 males; age 63.0+/-13.5 years) completed the study. Baseline end-dialysis body weight (62.4+/-13.7 kg) showed a non-significant 1% reduction during follow-up (-0.6+/-2.8 kg; P=0.175), whereas V significantly decreased from 29.0+/-6.8 to 27.4+/-6.0 l (-1.6+/-3.0 l or 4.5%; P=0.002). The reduction in V was greater when baseline albumin was lower (P=0.001) and baseline V was higher (P=0.005). The single-pool K(t)/V calculated using baseline V underestimated the actual value by 0.07+/-0.16 (P=0.008). The slight underestimate of Kt/V during follow-up suggests that annual V evaluations may be sufficient for dialysis dose quantification as the only risk is underestimating the actually delivered dialysis dose. However, the relationship between baseline albumin and the reduction in V over time may have nutritional value, and suggests more frequent V evaluations.

Identifying critically ill patients at high risk for developing acute renal failure: a pilot study

BACKGROUND

Acute renal failure (ARF) occurs commonly in the intensive care unit (ICU), but predicting which patients will develop ARF is difficult. We set out to determine which risk factors would predict the development of ARF in critically ill patients who are admitted to the ICU without ARF.

METHODS

From August 2002 to April 2003, we enrolled medical-surgical ICU admissions into a cohort using a sampling tool based on their risk factor (RF) profile. The risk factors we identified were separated into 3 categories: chronic major, chronic minor, and acute RFs. Combinations of these RFs were used to create a sampling tool and identify patients to enroll into our cohort. Patients with end-stage renal disease and ARF upon admission to the ICU were excluded.

RESULTS

We enrolled 194 patients over a 14-month period. The mean age of the cohort was 64.6 +/- 14.7 years. The percentage of Caucasians, African Americans, and Hispanics was 40.7%, 50.5%, and 3.6%, respectively. In a univariate analysis of the entire cohort, increasing APACHE II quartile, increased A-a gradient, presence of systemic inflammatory response syndrome (SIRS), decreased levels of serum albumin, and presence of active cancer predicted ARF. In a multiple logistic regression analysis, decreased serum albumin (high levels of serum albumin were protective), increased A-a gradient, and cancer were associated with development of ARF (OR 2.17, 1.04, and 2.86, respectively).

CONCLUSION

Decreased levels of serum albumin concentration, increased A-a gradient, and presence of active cancer predict which patients who are admitted to the ICU will develop ARF.

Serum ghrelin concentrations in patients with chronic renal failure undergoing dialysis

BACKGROUND

Ghrelin is a recently discovered protein hormone mainly synthesized in the gastric endocrine cells. This hormone not only is a potent growth hormone secretagogue but also is involved in the regulation of food ingestion and energy metabolism. Derangements in ghrelin secretion in patients with chronic renal failure (CRF) have not been fully evaluated.

OBJECTIVE

Our aim has been to quantify serum concentrations of total ghrelin in a group of patients with CRF on chronic therapy with both haemodialysis (HD) and peritoneal dialysis (PD) in comparison with a group of patients on conservative management (predialysis).

PATIENTS AND MEASUREMENTS

We studied 68 CRF patients treated by HD (n = 30, 16 men, age 61.2 +/- 1.8 years) and PD groups (n = 38, 21 men, age 54.4 +/- 1.7 years). A group of 19 uraemic patients on conservative management served as the control. Serum concentrations of ghrelin, leptin, insulin, IGF I and GH were measured in all subjects.

RESULTS

Patients undergoing HD showed similar concentrations of ghrelin in comparison with the control group (9491 +/- 787 vs 9280 +/- 918 pg/ml, NS). However, PD patients exhibited baseline ghrelin concentrations significantly lower than those found in patients on conservative management (3230 +/- 216 pg/ml, P < 0.0001). Men and women showed similar serum ghrelin levels in both HD (9845.9 +/- 1071 vs 9085 +/- 1194 pg/ml) and PD patients (3214 +/- 297 vs 3250 +/- 324 pg/ml). Hypertension and diabetes mellitus did not influence ghrelin levels. Serum GH levels were positively correlated with serum ghrelin concentrations in both HD (r = 0.46, P < 0.05) and PD (r = 0.53, P < 0.001) patients; however, no relationships between ghrelin, leptin, insulin and IGF I were found.

CONCLUSIONS

These results suggest that PD is accompanied by a striking decrement in baseline ghrelin concentrations in comparison with values found both in HD and control patients. Further studies are necessary to determine mechanisms involved in ghrelin regulation in uraemic patients.

The morbidity and cost implications of hemodialysis clinical performance measures

Clinical performance measures, including dialysis dose, hemoglobin, albumin, and vascular access, are the focus of monitoring and quality improvement activities. However, little is known about the implications of clinical performance measures for hospital utilization and health care costs. We obtained clinical performance measures and hospitalization records for a national random sample of 10,650 hemodialysis patients and analyzed the relationship between changes in clinical performance measures and hospital utilization after adjustment for patient demographic and medical characteristics. Higher hemoglobin, higher albumin, and fistula or graft use were independently associated with fewer hospitalizations, fewer hospital days, and decreased Medicare inpatient reimbursement. For example, a 0.5 g/dL higher hemoglobin, a 0.25 g/dL higher albumin, fistula use, and graft use were associated with hospitalization rate ratios of 0.90 (95% confidence interval 0.85, 0.96), 0.64 (0.53, 0.77), 0.60 (0.52, 0.69), and 0.79 (0.71, 0.89), respectively. Moreover, there was a 2-3-fold variation in hospital utilization across end-stage renal disease networks that was still evident after adjustment for patient characteristics and clinical performance measures. Clinical performance measures, especially albumin and vascular access, are strongly associated with hospital utilization and health care costs. These results highlight the importance of targeting nutrition and vascular access in quality improvement efforts. The marked variation in hospital utilization across networks deserves further examination.

Surrogate nutrition markers, malnutrition, and adequacy of nutrition support

Surrogate nutrition markers are used to assess adequacy of nourishment and to define malnutrition despite evidence that fails to link nourishment, surrogate markers, and outcomes. Markers such as serum levels of albumin, prealbumin, transferrin, and IGF-1 and delayed hypersensitivity and total lymphocyte count may be valid to help stratify risk. However, it is not appropriate to consider these as markers of adequacy of nourishment in the sick patient.

Association between serum bicarbonate and death in hemodialysis patients: is it better to be acidotic or alkalotic?

The optimal acid-base status for survival in maintenance hemodialysis (MHD) patients remains controversial. According to recent reports, acidosis is associated with improved survival in MHD patients. It was hypothesized that this inverse association is due to a confounding effect of the malnutrition-inflammation complex syndrome (MICS). Associations between baseline (first 3 mo averaged) predialysis serum bicarbonate (HCO3(-)) and 2-yr mortality were examined in 56,385 MHD patients who were treated in virtually all DaVita dialysis clinics across the United States. The range of HCO3(-) was divided into 12 categories (< 17, > or = 27, and 10 groups in between). Three sets of Cox regression models were evaluated to estimate hazard ratios of all-cause and cardiovascular death in both incident and prevalent patients: (1) Unadjusted, (2) multivariate case mix adjusted (which also included dialysate HCO3(-) and Kt/V), and (3) adjusted for case mix and nine markers of MICS (body mass index; erythropoietin dose; protein intake; serum albumin; creatinine; phosphorus; calcium; ferritin and total iron binding capacity; and blood hemoglobin, WBC, and lymphocytes). There were significant inverse associations between serum HCO3(-) and serum phosphorus and estimated protein intake. The lowest unadjusted mortality was associated with predialysis HCO3(-) in the 17- to 23-mEq/L range, whereas values > or = 23 mEq/L were associated with progressively higher all-cause and cardiovascular death rates. This association, however, reversed after case-mix and MICS multivariate adjustment, so that HCO3(-) values >22 mEq/L had lower death risk. Although previous epidemiologic studies indicated an association between high serum HCO3(-) and increased mortality in MHD patients, this effect seems to be due substantially to the effect of MICS on survival.

Does provision of a higher Kt/V urea make a difference? A hemodialysis controversial issue

BACKGROUND

Adequate dialysis cannot be ascertained on the sole base of a normal or even a high Kt/V(urea) so the impetus of this study was to use the neurophysiologic studies as a marker of the biologic status of the hemodialysis patients to assess the optimum level of Kt/V(urea).

METHODS

This study was carried out on 20 patients (15 men and 5 women) on maintenance hemodialysis; their ages ranged from 18 to 66 years. Initially, the patients were subjected to thorough clinical and laboratory investigations, and their dialysis adequacy was assessed by studying their urea kinetic modeling and neurophysiologic studies (Phase I). Dialysis was optimized to achieve a target Kt/V(urea) of 1.3 in Phase II and 1.5 in Phase III. The duration of each phase was six months at the end of which all patients were thoroughly reevaluated. Nutrition was not manipulated during the study.

RESULTS

A neurophysiologic study showed a significant improvement of polyphasicity pattern of both proximal and distal muscles of the upper and lower limbs concomitant with improvement of quality of life on achieving a Kt/V(urea) of 1.5 (p < 0.001). There was no significant change of the duration and amplitude of all studied muscles, however.

CONCLUSION

Achieving a Kt/V(urea) of 1.5 is a more suitable target for hemodialysis patients because it may be an avenue for improving the neuromuscular functions of these patients.

Relationship between urea clearance and ionic dialysance determined using a single-step conductivity profile

BACKGROUND

On-line determination of ionic dialysance (ID) has been used to measure the clearance of small solutes like urea. However, attempts to determine the in vivo relationship between ID and urea clearance have led to discordant findings. The aim of this study was to determine the relationship between the mean values of repeated instantaneous determinations of ID throughout a dialysis session ((m)ID), obtained using a single-step inlet dialysate conductivity profile, and the mean values of urea clearance corrected for access recirculation (K(eu1)), total recirculation (access plus cardiopulmonary recirculation, K(eu2)), and the entire postdialysis urea rebound (K(wb)).

METHODS

Eighty-two anuric patients on chronic thrice-weekly hemodialysis were studied using an Integra machine equipped with the Diascan module for the automatic determination of ID. The mean values of repeated ID measurements made at 30-minute intervals were compared with K(eu1) (available for only 31 patients), K(eu2), and K(wb).

RESULTS

The results in all 82 patients were: (m)ID = 176 +/- 23 mL/min; K(eu2) = 181 +/- 25 mL/min; K(wb) = 159 +/- 22 mL/min. The mean (m)ID/K(wb) and (m)ID/K(eu2) ratios were, respectively, 1.11 +/- 0.06 and 0.98 +/- 0.06. The results in the 31 patients for whom K(eu1) values were available were: (m)ID = 179 +/- 24 mL/min and K(eu1) = 200 +/- 27 mL/min; the mean (m)ID/K(eu1) ratio was 0.90 +/- 0.05.

CONCLUSION

The mean value of repeated ID determinations obtained using a single-step conductivity profile underestimates urea clearance corrected for access recirculation, and may be considered an adequate estimate of urea clearance corrected for total recirculation.