Total Nitrogen Appearance Research Articles

Peritoneal Phosphate Clearance: Determinants and Association With Mortality.

Dialytic phosphate removal is a cornerstone of the management of hyperphosphatemia in peritoneal dialysis (PD) patients, but the influencing factors on peritoneal phosphate clearance (PPC) are incompletely understood. Our objective was to explore clinically relevant factors associated with PPC in patients with different PD modality and peritoneal transport status and the association of PPC with mortality. This is a cross-sectional and prospective observational study. Four hundred eighty-five PD patients were enrolled and divided into 2 groups according to PPC. All-cause mortality was evaluated after followed-up for at least 3 months. High PPC group showed lower mortality compared with Low PPC group by Kaplan-Meier analysis and log-rank test. Both multivariate linear regression and multivariate logistic regression revealed that high transport status, total effluent dialysate volume per day, continuous ambulatory PD (CAPD), and protein in total effluent dialysate volume appeared to be positively correlated with PPC; body mass index (BMI) and the normalized protein equivalent of total nitrogen appearance (nPNA) were negatively correlated with PPC. Besides PD modality and membrane transport status, total effluent dialysate volume showed a strong relationship with PPC, but the correlation differed among PD modalities. Higher PPC was associated with lower all-cause mortality risk in PD patients. Higher PPC correlated with CAPD modality, fast transport status, higher effluent dialysate volume and protein content, and with lower BMI and nPNA.

Correlation of the Dietary Protein Intake between Those Estimated from a Short Protein Food-Recall Questionnaire and from 24-Hour Urinary Urea-Nitrogen Excretion in Stages 3-4 Chronic Kidney Disease Patients.

High protein intake may accelerate progression of chronic kidney disease (CKD). Estimation of dietary protein intake (DPI) is indispensable for management of CKD, but to achieve optimum DPI is quite challenging in routine clinical practice. We recently studied a beneficial effect of utilizing integrated care on the management of CKD at the rural community level. In that study, we created a short protein food-recall questionnaire (S-PFRQ) as a working tool to estimate DPI of the CKD patients during home visit by community health personnel. Herein, we reported the initial evaluation of the reliability of S-PFRQ from our previous study. We compared the amount of DPI obtained from S-PFRQ with that obtained from protein-equivalent of total nitrogen appearance (PNA). In the previous ESCORT-2 study, 914 patients with CKD stage 3 or 4, who were living in the rural area of Thailand, were prospectively followed while receiving integrated care for 36 consecutive months. During home visits by community nurses from subdistrict health centers, dietary food recall was made, recorded in S-PFRQ, and DPI was obtained. Among these, sixty patients were randomly selected, and 24-h urine was collected for urinary urea-N and estimation of PNA. A correlation was made between DPI obtained from S-PFRQ and PNA. The DPIs derived from S-PFRQ and PNA were 28.8 ± 14.8 and 39.26 ± 17.79 g/day, respectively. The mean difference and 95% CI between the 2 methods was -10.43 (-7.1 to -13.8) g/day, respectively (P < 0.001). Interclass correlation between these 2 methods was 0.24, P = 0.007. The difference between the 2 methods remained constant across different amounts of DPI. The DPI estimated from S-PFRQ significantly correlated to that from PNA. However, the S-PFRQ method yielded a DPI value which was about 10 g of protein or 25% less than the PNA method. Despite this amount of difference, this S-PFRQ is user-friendly and could be used during field work as an easy and simple tool for DPI estimation in resource-limiting condition.

Use of low-protein staple foods in the dietary management of patients with stage 3\u20134 chronic kidney disease: a prospective case-crossover study

ObjectiveMaintaining a low-protein diet (LPD) is important for patients with chronic kidney disease (CKD) to delay renal degradation and alleviate clinical symptoms. For most patients with CKD, it is difficult to maintain the necessary low level of dietary protein intake (DPI). To improve the current dietary management of CKD, we conducted an intervention study by administering low-protein staple foods (LPSF).Design and methodsWe conducted a prospective case-crossover study among 25 patients with stage 3–4 CKD. During the initial 12 weeks of the study, we instructed the patients regarding a standard LPD according to the recommendations of a renal dietitian. In the second stage of the study, we requested the patients taking low-protein rice or low-protein flour (250 g/d) as an LPSF diet instead of regular staple food daily, and followed these patients up for 12 weeks. We compared the DPI, dietary energy intake (DEI), normalized protein equivalent of total nitrogen appearance (nPNA), serum creatinine levels, and nutritional index between baseline and the end of the study.ResultsWe found no change in dietary variables among the patients during the first 12 weeks of the LPD. After subjecting them to an LPSF diet, the corresponding variables showed a pronounced change. The patients’ DPI decreased from 0.88 ± 0.20 to 0.68 ± 0.14 g/kg/d (P < 0.01) and the nPNA value decreased from 0.99 ± 0.18 to 0.87 ± 0.19 g/kg/d (P < 0.01). The high biological value protein intake proportion increased from 42% (baseline) to 57% (P < 0.01) during the 24 weeks. No variation was found in the measured DEI (28.0 ± 5.8 vs 28.6 ± 5.4 kcal/kg/d), nutrition assessment, or renal function and serum creatinine levels.ConclusionOur prospective case-crossover study demonstrated that an LPSF diet can help patients with stage 3–4 CKD reduce DPI and nPNA values, improve the proportion of highly bioavailable proteins, ensure adequate calorie intake, and avoid malnutrition. An LPSF diet is an effective and simple therapy for patients with stage 3–4 CKD.

The estimation of protein equivalents of total nitrogen in Chinese CAPD patients: an explanatory study

Objective The protein equivalent of total nitrogen appearance (PNA) formula, based on the urea nitrogen appearance (UNA), is popularly used by stable continuous ambulatory peritoneal dialysis (CAPD) patients to estimate dietary daily protein intake (DPI). However, we found that the estimated DPI was higher than that directly evaluated from the dietary records of most of our CAPD patients. Therefore, in the present study, we tried to determine possible bias in PNA estimation by UNA with a nitrogen balance study of our CAPD patients. Methods Thirty-one CAPD patients with stable clinical conditions were included. Their 3-day dietary records were reviewed by a dedicated dietitian to calculate their energy, protein, and nitrogen intake (NI). The nitrogen removal (NR) from urine and dialysate was measured by the Kjeldahl technique. Then, we calculated the proportion of urea nitrogen appearance (UNA) in total nitrogen appearance (TNA) and analyzed the possible factors that could affect this proportion. Results Among these patients, 17 males and 14 females, the mean age was 64.19 ± 12.42, and the dialysate drainage volume was 6700 (2540) ml/day. The percentage of UNA in TNA was 63.22 ± 6.66%. Compared with the other classic nitrogen balance studies in the CAPD population, the protein nitrogen and other nonurea nitrogen losses in this study were all lower. Based on these 31 nitrogen balance studies, we proposed a pair of new equations to estimate PNA by UNA. (1) PNA = 9.3 + 7.73 UNA; (2) PNA = PNPNA + TPL = 6.7 + 7.28 UNA + TPL. Conclusion Our study suggested that the PNA formula generated from previous European studies overestimated DPI in our CAPD patients.

Trimethylamine-N-oxide (TMAO) and clinical outcomes in patients with end-stage kidney disease receiving peritoneal dialysis.

Trimethylamine-N-oxide (TMAO) is a gut bacteria-derived metabolite of l-carnitine and choline. A high concentration of TMAO has been proven to relate to cardiovascular disease (CVD), all-cause mortality and chronic kidney disease progression. We aimed to investigate the relation between the value of serum TMAO and outcomes for peritoneal dialysis (PD) patients. This is a prospective cohort study with data retrospectively analysed. All incident PD patients were enrolled and followed up. Log-rank test, competing risk survival analysis and COX regression were performed to test the effect of serum TMAO on developing first-episode peritonitis, all-cause and CVD mortality. A wide distribution of serum TMAO concentration was observed in 513 PD patients, with a median level of 72.3 (43.7, 124.7) µmol/L. Patients with lower TMAO concentration were more likely to be without diabetes and hypertension. Patients with lower TMAO concentration showed better residual kidney function and solute clearance at baseline. Participants in the higher three TMAO quartiles showed an increased risk for first-episode peritonitis (p = 0.039). By competing risk survival analysis, after adjusting for age, sex, diabetes mellitus, CVD, body mass index, albumin, high-sensitive C-reactive protein, potassium, phosphorus, residual kidney function, normalised protein equivalent of total nitrogen appearance and calendar year of catheter implantation, patients in the higher three TMAO quartiles had a statistically or marginally higher risk for first-episode peritonitis compared with patients in the lowest quartile, with hazard ratio (HR) 1.65 (1.05, 2.58), 1.46 (0.92, 2.31) and 1.66 (1.05, 2.61), respectively. In the COX model, patients in the third quartile TMAO group had significantly higher CVD mortality risk compared with the lowest quartile group, as HR 2.27 (1.02, 5.05) after adjusting for various factors. As for all-cause mortality, TMAO did not show any associated effects. Serum TMAO concentration is associated with the risk of first-episode peritonitis and CVD mortality in PD patients. No obvious association between serum TMAO and all-cause mortality was observed.

Nutritional predictors associated with malnutrition in continuous ambulatory peritoneal dialysis patients.

Currently in China, out of the total dialysis population, approximately 20% represents continuous ambulatory peritoneal dialysis (CAPD) and almost half of CAPD patients was affected by malnutrition. This study aimed to investigate the association between nutritional predictors and malnutrition with 5.1 years of dialysis according to the subjective global assessment (SGA) in continuous ambulatory peritoneal dialysis (CAPD) patients. A cross-sectional study was conducted from April 2013 to May 2018 and included 70 CAPD patients. The relationship between anthropometric and biochemical parameters with malnutrition was assessed by multiple logistic regression analysis. The prevalence of malnutrition in CAPD patients was 52.9%. Our result revealed a 7.05-fold increased odds of malnutrition for patients with protein equivalent of total nitrogen appearance normalized to body weight (nPNA)<1.0g/kg per day (d) versus patients with normal nPNA (confidence interval (CI) 1.33-37.34; p<0.05). Patients whose normalized protein catabolic rate (nPCR) was <1.2g/(kg/d) had a significant positive association with malnutrition versus patients with normal nPCR (adjusted odds ratio (OR) 7.99; p<0.05). Patients with dietary protein intake (DPI)<1.0g/(kg/d) had a higher likelihood of malnutrition than those with normal DPI (OR 12.73; p<0.05). CAPD patients with upper arm circumference (UAC)<23.2cm had a high risk of malnutrition versus patients with normal UAC (OR 12.99; p<0.05). Our study suggested a close association between nPNA, DPI, nPCR, and UAC and malnutrition in CAPD patients. Further studies can be warranted the use of these variables as predictors and a malnutrition consequence among Chinese CAPD patients.

Protein-Energy Wasting and Mortality Risk Prediction Among Peritoneal Dialysis Patients

Protein-energy wasting (PEW) is defined as the loss of body protein and energy reserves associated with kidney disease. However, the extent to which PEW contributes to increased mortality among peritoneal dialysis (PD) patients remains unclear. This is a retrospective cohort study from 2012 to 2020. The PEW was diagnosed by applying at least 3 of the 4 following criteria: (1) altered serum biochemistry indicated by a serum albumin level of <3.5g/L; (2) decreased body mass status identified by a body mass index (BMI) of <23kg/m2 or <10% total body fat; (3) muscle wasting defined by the lean tissue index, calculated as a lean tissue mass normalized to the height-squared in the <10th percentile of the reference population; and (4) low dietary protein intake determined by the normalized protein equivalent of a total nitrogen appearance of <0.8g/kg/day. The Malnutrition Inflammation Score (MIS) was also examined as an alternative tool for assessment of PEW. The average age of the 555 participants was 57.5±12.6years. The prevalence of PEW was 27.3%, with 196 deaths observed during the mean follow-up of 25.5months. Patients with PEW who fulfilled at least 3 of the 4 listed criteria had a higher risk of death in the unadjusted model (hazard ratio 1.61, 95% confidence interval 1.19-2.18, P=.002). However, these associations were attenuated after adjusting for potential confounders. Regarding the individual PEW criterion, decreased serum albumin and low muscle mass were significantly associated with mortality in the multivariable models. In contrast, decreased body mass and low protein intake were not associated with a higher risk of death. High MIS (≥5 points) and each one-point increase in the MIS were also significantly associated with higher risk of death in both unadjusted and adjusted models. Among PD patients, the presence of PEW was not a better predictor of all-cause mortality than either the altered serum biochemistry (albumin) or low muscle mass criteria. The MIS performed well as an independent predictor of death and might be an option for assessment of PEW status in the PD population.

Which Method Should Be Used to Assess Protein Intake in Peritoneal Dialysis Patients? Assessment of Agreement Between Protein Equivalent of Total Nitrogen Appearance and 24-Hour Dietary Recall

After dialysis initiation, a high protein diet is recommended due to significant nutrient losses through dialysate and increased risk of protein energy wasting. In peritoneal dialysis (PD) patients, protein intake can be assessed through different methods that have some advantages and limitations, which affect its use on routine care. The aim of this study is to evaluate the agreement between 2 different methods (24-hour dietary recall and PNA-protein equivalent of total nitrogen appearance) on estimating protein intake in PD patients. Patients on PD for at least 3months, aged 18years old or more, were enrolled. To estimate protein intake, 24-hour dietary recall and PNA was used. PNA was calculated from 24-hour urine on the same day of the 24-hour dietary recall. Fifty individuals on PD were included, mean age 55.7±16.2years, and body mass index 26.0±4.5kg/m2. The average energy consumption was 1788.79±504.40kcal/day, which corresponds to 26.81±9.11kcal/kg current body weight (BW)/day and 29.82±8.39kcal/kg ideal body weight (IBW)/day. The median of total daily and normalized protein intake estimated using dietary recall was 61.43 (45.28-87.40) g/day, 0.90 (0.58-1.22) g/kg current BW/day, and 1.04 (0.77-1.32) g/kg IBW/day, respectively. Daily protein intake estimated by PNA was 55.75 (48.27-67.74) g/day, protein intake normalized by current BW was 0.81 (0.72-0.99) g/kg and 0.92 (0.83-1.06) g/kg IBW/day. Bland-Altman analysis indicates no systematic bias for the assessment of total protein intake and normalized protein intake for current and ideal BW. Significant proportionality bias was observed for both evaluations, showing there is a dispersion of the values. Despite the absence of systematic bias in the Bland-Altman analysis, there is no agreement in the assessment of protein intake by dietary recall and PNA, due to the existence of proportionality bias. Thus, values can be influenced biased by the magnitude of the measures.

EFFECT OF RENAL SPECIFIC ORAL NUTRITION (ONCE RENAL) ON DIETARY INTAKE AND SERUM ELECTROLYTES IN CHRONIC KIDNEY DISEASE STAGE IV

Background and Objectives: Low nutritional intake is common in advanced chronic kidney disease (CKD) and poses a direct risk for malnutrition. Our study evaluated the effects of a renal specific oral nutrition (ONCE Renal) supplement concerning nutritional status, minerals and electrolytes among patients with stage IV CKD.&#x0D; Methods and Study Design: A total of 32 CKD patients with an estimated glomerular filtration rate 16-29 mL/min/1.73 m2, well nourished subjects and anticipated good compliance with the diet received the ONCE Renal diet instead of 1 meal daily for 30 days. Dietary protein and energy intake, body compositions, and serum concentrations of urea, creatinine, calcium, magnesium, phosphate and albumin were assessed at baseline, and at 30 days. A dietary intake by three-day food record were also evaluated by a registered dietitian.&#x0D; Results: At the end of 30 days, significant improvements in energy, fat, fiber and magnesium intake by dietary interview were noted. In addition, the patients also increased body weight and body mass index after supplement. No significant changes in renal function, serum electrolytes, calcium, phosphorus, magnesium concentration and other nutritional markers including serum albumin, body compositions and protein equivalence of total nitrogen appearance were observedduring study. The compliance with the ONCE Renal diet was good among enrolled patients and no adverse reactions were found.&#x0D; Conclusions: Renal specific oral diet supplement can improve energy intake, body weight and maintain serum electrolytes concentrations among patients with stage IV CKD.

The effect of ONCE Renal on minerals and electrolytes in predialysis patients with chronic kidney disease.

BackgroundMalnutrition is one common adverse consequence in patients with advanced chronic kidney disease (CKD), and most patients have a lower-than-normal dietary energy intake. The present study was undertaken to examine whether orally administered ONCE Renal formula (ORF) supplement would improve energy intake without minerals and electrolytes disturbances in predialysis patients with CKD.MethodsAll eligible nondiabetic patients with CKD received ORF supplement for 1 week. Nutrition markers, renal function, and minerals and electrolytes were evaluated before and after supplementing. All patients kept a 3-day food record and were interviewed by a registered dietitian.ResultsA total of 29 patients with mean age 64.9±13.3 years were included. Mean estimated glomerular filtration rate was 37.7±12.1 mL/min/1.73 m2. A significant increase was observed in amount of energy, fat, fiber, calcium, and magnesium intake after 1 week of ORF supplement. Moreover, in comparison with baseline values, the patients displayed decreased dietary protein intake and blood urea nitrogen and increased serum magnesium. However, no significant change was found in renal function, nutritional markers (body weight, prealbumin, albumin, and protein equivalence of total nitrogen appearance), serum calcium, phosphorus, sodium, potassium, and bicarbonate.ConclusionIn patients with CKD, ingestion of ORF was well tolerated and had a positive effect with an increase in dietary energy, fat, and fiber intake, as well as a decreased dietary protein intake. No mineral or electrolyte abnormalities were observed during the study.

EVALUATION OF NUTRITIONAL ASSESSMENT IN ELDER PATIENTS WITH CONTINUOUS AMBULATORY PERITONEAL DIALYSIS: COMPARING THE MINI NUTRITIONAL ASSESSMENT (MNA) WITH THE SUBJECT GLOBAL ASSESSMENT (SGA)

The DOQI 2000 recommends the subjective global assessment(SGA)for the nutritional evaluation in patient with continuous ambulatory peritoneal dialysis(CAPD). In 1990s, the mini nutritional assessment (MNA)has been used successfully in the evaluation of the nutrition status in the flail elder person. Is it more suitable for MNA than SGA in assessment the nutrition of elder CAPD patient? In this study, we compared the MNA method with the traditional SGA in the evaluating the nutritional status in elder CAPD patients. We used the cross-sectional study with selection of the patient. Forty-five elder CAPD patients 21 male and 24 female with more than 60 years old, were enrolled in this study. SGA and MN questionnaire, anthropometric parameters and laboratory test were investigated in those patients. The normalized protein equivalent of total nitrogen appearance (nPNA) was calculated. The result were: 1)These patients were classified into three nutritional classes according to the SGA (i.e. normal nutrition SGA considered as A, mild to moderate malnutrition SGA as B, and severe malnutrition SGA as C). The corresponding, classification according to the MNA was normal nutrition(MNAl), at risk of malnutrition(MNA2), and severe malnutrition(MNA 3). In the SGA classification, 49% were assessed as A, 31% in B and 20% in C, while the corresponding figures in MNA Was 40% in MNA 1, 38% in MNA 2 and 22% in MNA 3. Either in SGA or in MNA assessment . the dietary protein intake (DPI), dietary energy intake (DEI), serum albumin(Alb), nPNA, months On CAPD, residual renal function(RRF), and the adequacy indices(Kt/v, Ccr) were significantly different among three groups(P 0.05). Only in severe malnutrition group, both in SGA and MNA, the abnormal rates of all measures were above 80% for DEI or DPI and Alb, except for Prealbumin. 2) There were no significant differences between the classes, irrespective of methods. The kappa test, was used to compare the result of two methods, and the kappa value was 0.545 5(P

Amino Acid Balance with Extended Daily Diafiltration in Acute Kidney Injury

Background: The impact of hybrid dialysis therapies on amino acid (AA) balance in critically ill patients with acute kidney injury is unknown. Methods: We examined prospectively the AA balance with extended daily diafiltration (EDDF). Results: We studied 7 patients. AA clearances with EDDF ranged from 21.6 ml/min (tryptophan) to 66.9 ml/min (taurine). AA loss was 4.2 (IQR 1.4–12.3) g/day and 4.5% of daily protein intake for patients on enteral nutrition (EN). Percentage AA loss per hour on EDDF was highest for glutamine (32.1%) and lowest for glutamic acid (0.8%). Blood AA levels correlated with corresponding EDDF losses. Median total nitrogen appearance was 25.0 (IQR 20.6–29.3) g/day for patients on EN. This resulted in a negative nitrogen balance of –10.7 (IQR –16.6 to –1.4) g/day, of which 6.5% was attributable to AA loss. Conclusions: AA loss with EDDF was limited, but with much individual variability, and contributed to a strongly negative daily nitrogen balance.

Helicobacter pylori Infection: Protective Against Increased Interdialytic Weight Gain in Asymptomatic Hemodialysis Patients?

Infection with Helicobacter pylori, which induces persistent and uncontrolled gastric inflammation leading to decreased appetite, might be protective against obesity. There is a close relationship between interdialytic weight gain (IDWG) and nutritional parameters, confirming the role of IDWG as a marker of calorie and protein intake in hemodialysis (HD) patients. Hypothesis of the present study was that infection with H pylori in subjects with uremia might cause inflammation, diminished appetite, anorexia, and decreased IDWG. A cross-sectional study was conducted. This trial involved HD patients from a state hospital. Demographic, laboratory, and clinical parameters were collected. All patients were clinically stable and euvolemic and their average IDWG percent was calculated. Malnutrition inflammation score, spKt/V, and normalized protein equivalent of total nitrogen appearance were determined. Patients were asked to rate their appetite status from 1 to 5 on a Likert scale (very good, good, fair, poor, and very poor appetite, respectively). An H pylori infection was detected by the H pylori stool antigen (HpSA) in all the patients. HpSA was positive in 18 (30%) patients. None of the demographic and laboratory parameters differed between patients infected with HpSA and the noninfected patients. Stepwise linear regression analysis of independent factors related with IDWG% revealed that daily urine output (β = -0.432, P < .0001), serum phosphorus (β = +0.343, P = .004), and hemoglobin (β = +0.358, P = .003) were related with IDWG%. Infection with H pylori is not related with IDWG% and nutritional parameters in HD patients.

Troponin I and Cardiovascular Events in Transplant Patients

We have carefully read the recently published article in Transplantation by Claes et al. (1). The authors clearly demonstrated that elevated pretransplant troponin I is an independent predictor of major adverse cardiac events in transplant patients. Recently, we have demonstrated that in asymptomatic hemodialysis patients, silent myocardial damage as defined by elevated cardiac troponin I (cTnI) levels were associated with both traditional and nontraditional cardiovascular risk factors. Among the factors related with elevated cTnI were found to be diabetes mellitus, left ventricular hypertrophy, uncontrolled blood pressure, normalized protein equivalent of total nitrogen appearance, hemoglobin, and tumor necrosis factor-α (2). In common with our study, Claes et al. also reported that troponin I levels were correlated with the presence of diabetes and C-reactive protein. Thus, by the light of these two studies, we believe that some of the factors for elevated cTnI levels may be predictable (e.g., diabetes, inflammation). Because elevated cTnI is found to be a risk factor for future cardiac events, including myocardial infarction, cardiac death, and revascularization in asymptomatic patients with chronic renal failure (3–5), factors related with elevated cTnI level should also be defined. Bearing these issues in mind, we wonder whether Claes et al. would give further information whether the blood pressure measurements and the presence of hypertension at the time of transplantation were related with elevated troponin I levels. We also wonder whether any nutritional parameter other than albumin were related with elevated troponin I levels. Finally, we would like to learn whether the authors suggest routine coronary angiography to patients with elevated troponin I levels. Baris Afsar Rengin Elsurer Department of Nephrology Zonguldak Atatürk Government Hospital Zonguldak, Turkey

Are Ghrelin and Leptin Involved in Food Intake and Body Mass Index in Maintenance Hemodialysis?

Both leptin and ghrelin (in the forms of acyl ghrelin and des-acyl ghrelin) are involved in food intake, and appear to be dysregulated in chronic kidney disease. This study describes plasma leptin, acyl, and des-acyl ghrelin concentrations in relation to protein intake and body mass index (BMI) in hemodialysis (HD) patients. This was a cross-sectional study. This study was conducted during the baseline phase of the French multicenter Influence of a High-Flux Dialyzer on Long-Term Leptin Levels Study. We studied 125 HD patients (aged 72.5+/-11.7 years; 59% males). Blood samples were collected during fasting, and before a regular HD session. Plasma ghrelin and leptin were evaluated. The protein equivalents of total nitrogen appearance and BMI were calculated. Patients demonstrated elevated serum leptin (48.0+/-49.0 ng/mL) and des-acyl ghrelin (646.6+/-489.5 pg/mL) levels, and low acyl ghrelin levels (29.8+/-58.5 pg/mL), according to normal values. Acyl ghrelin was negatively correlated with C-reactive protein (r=-0.34, P < .001). The des-acyl to acyl ghrelin ratio was negatively correlated with protein intake, as estimated by normalized Protein Nitrogen Appearance (r=-0.22, P=.01). Serum leptin exhibited its well-described positive correlation with BMI and waist circumference, but the other hormones did not. This study reports high des-acyl ghrelin and leptin levels and low acyl ghrelin levels in HD patients, a finding potentially associated with inflammation and food intake.

Factors Related to Silent Myocardial Damage in Hemodialysis Patients

Background. Both traditional and non-traditional risk factors play a role for the development of cardiovascular disease in hemodialysis patients. However, a specific relationship between these risk factors and silent myocardial damage is unknown. Methods. Demographic, anthropometric, clinical, and laboratory data were collected. Silent myocardial damage was defined by elevated cardiac troponin I values above cutoff values. Results. In total, 113 hemodialysis patients were included. Cardiac troponin I concentrations were below cutoff value (<2.3 ng/mL) in 103 (91.2%) patients (Group 1), whereas 10 (8.8%) patients had elevated concentrations (Group 2). Group 1 patients had higher levels of hemoglobin (p = 0.002) and high-density lipoprotein cholesterol (p = 0.002) and lower C-reactive protein (p = 0.003) and tumor necrosis factor-α (p = 0.005) levels, as well as less incidence of left ventricular hypertrophy (p = 0.045), when compared to Group 2 patients. Diabetes mellitus (Beta = +0.160, p = 0.021), left ventricular hypertrophy (Beta = +0.247, p < 0.0001), uncontrolled blood pressure (Beta = +0.170, p = 0.016), normalized protein equivalent of total nitrogen appearance (Beta = −0.230, p = 0.001), hemoglobin (Beta = −0.302, p < 0.0001), and tumor necrosis factor-α (Beta = +0.506, p < 0.0001) were found to be independently associated with cardiac troponin I levels in multiple linear regression analysis. Conclusions. Both traditional and non-traditional risk factors are related with silent myocardial damage, which is considered to an antecedent of major cardiovascular events. Hemodialysis patients, even when asymptomatic, must be closely followed up for the presence of these risk factors.

Dietary Protein Requirements and Dialysate Protein Losses in Chronic Peritoneal Dialysis Patients

Recommended dietary protein allowances for chronic peritoneal dialysis (PD) patients are approximately 60% higher than the dietary protein allowances for healthy adults. The relative contribution of dialysate protein and amino acid losses to these high protein requirements or total nitrogen losses is uncertain. Following a peritoneal equilibration test, two 24-hour dialysate collections (24-1 and 24-2) were performed in 9 stable patients undergoing automated PD [4 males, 3 diabetics, age 43 +/- 5 years (mean +/- SEM), dialysis vintage 42 +/- 6 months, dialysate-to-plasma ratio of creatinine 0.61 +/- 0.04]. Dialysate effluent from nighttime cycling was collected separately from the daytime dwells. The measured 24-hour protein losses were 9.4 +/- 0.6 (24-1) and 10.8 +/- 0.8 (24-2) g/day. Even though day dwells accounted for 27% of daily dialysate volume, they accounted for 40% of daily protein and amino acid losses. The frequency of nighttime cycling and duration of dwell were significant predictors of peritoneal protein losses. Dialysate protein and amino acid losses constituted 24% +/- 2% and 3.1% +/- 0.3% of dialysate nitrogen and 14% +/- 1% and 1.7% +/- 0.1% of dietary nitrogen intake respectively. Treatment with automated PD is associated with somewhat higher 24-hour dialysate protein losses compared to previous reports among continuous ambulatory PD patients. Dialysate protein and amino acid losses constitute a small, albeit significant, proportion of total nitrogen appearance and thus may contribute to the increased dietary protein requirements of chronic PD patients.

Effect of Protein and Energy Intakes on Body Composition in Non-Diabetic Maintenance-Hemodialysis Patients

This cross sectional study was performed to find the adequate amount and combination of dietary protein and energy for maintaining better nutritional status for stable non-diabetic maintenance hemodialysis (MHD) patients. The body composition including body fat, total body water, body cell mass and body protein were measured by multi-frequency bioelectrical impedance analysis in 200 stable MHD patients without diabetes (124 men, 76 women). Dietary energy intake (DEI) and dietary protein intake (DPI) were assessed by a brief self-administered diet history questionnaire (BDHQ), the DPI value being confirmed by calculating the normalized protein equivalent of total nitrogen appearance (nPNA). The nutritional status and the body composition were compared among 4 groups of patients in each gender that were divided by the combination of DEI and DPI; high energy (HE)/high protein (HP), HE/low protein (LP), low energy (LE)/HP and LE/LP groups. The mean DPI ranged between 1.17-1.23 and 0.89-0.95 g/kg IBW/d in the HP and LP groups, respectively for both genders, and the mean DEI was 35-37 and 24-25 kcal/kg IBW/d in HE and LE groups, respectively. BMI and serum albumin concentration were not different among the 4 groups. Body cell mass index (BCMI) was maintained in the HE groups regardless of DPI, and it was significantly higher in the HE/HP group than in the LE/LP group. Multiple regression analysis also showed that the BCMI was more greatly affected by DEI than DPI. These results indicated that a DPI of 0.89-0.95 g/kg IBW/d could be sufficient for maintaining BCMI, if DEI is kept over 35 kcal/kg IBW/d in stable non-diabetic MHD patients. This DPI level is lower than the recommended DPI proposed by dietary guidelines in the US and Japan.

Kt/V and nPNA in pediatric peritoneal dialysis: a clinical or a mathematical association?

The relationship between dialysis dose and nutrition is a field of particular interest in chronic pediatric dialysis (PD), and a positive correlation between ureaKt/V and nPNA has been published, suggesting a better nutritional status is associated with higher dialysis doses. However, this relationship has also been criticized as being the result of a mathematical coupling resulting from the same variables. The objective of the study was to establish the relationship between dialysis dose (Kt/V) and nutritional variables: daily protein intake (DPI), protein catabolic rate (PCR), protein equivalent of total nitrogen appearance (PNA) and nitrogen balance (NB) in dialyzed children. A cohort, prospective, observational study was carried out, for which 223 biochemical measurements were performed in 20 patients, ages 1 month to 14.3 years old (13 males), under PD for a 12-month period of follow-up. Monthly residual and total ureaKt/V, DPI, PCR, nPNA and NB were calculated, and the correlation between Kt/V and the nutritional parameters was evaluated. The Borah equation was used to calculate the nPNA. The data are reported as the mean plus or minus the standard error. All statistical comparisons were done with a paired t test, and two-way ANOVA for repeated measures was used to calculate correlations. A P <0.05 was considered significant. Mean total and residual Kt/V was 3.4+/-1.3 and 1.69+/-1.27, respectively; nPNA and PCR were 1.38+/-0.44 and 1.39+/-0.43 g/kg/day, daily protein intake (DPI) was 3.25+/-1.27 g/kg/day, and NB showed a value of 1.86+/-1.25 g/kg/day. A significant positive correlation was found between Kt/V and DPI, PCR, DPC and nPNA (all values P <0.0001), but no correlation was found between total and residual Kt/V vs. nitrogen balance ( P:ns). Total Kt/V showed a significant positive correlation with nPNA, but it did not show any correlation with nitrogen balance, suggesting that the relationship with nPNA is the result of a mathematical association calculated from the same variables.

Urea Kinetics and Clinical Chemistry Parameters in Patients on Twice-Weekly Hemodialysis

Despite the fact that thrice-weekly hemodialysis is regarded as the standard for maintenance dialysis, prescription of twice-weekly hemodialysis with a longer treatment time is common in Hong Kong to allow more renal failure patients to receive treatment. In an attempt to assess whether clinical and biochemical parameters differ between hemodialysis with different interdialytic intervals, we investigated the urea kinetics and blood biochemistry parameters in patients undergoing two dialysis sessions per week. Data were collected for 16 anuric stable maintenance dialysis patients for two dialyses in the same week. Compared with hemodialysis after a short interdialytic interval (HD SII ), hemodialysis after a long interdialytic interval (HD LII ) led to significantly greater interdialytic weight gain. Predialysis plasma potassium, urea and creatinine concentrations were significantly higher for HD LII . On the other hand, there were no significant differences in predialysis plasma sodium, chloride, total carbon dioxide, albumin, calcium and phosphorus concentrations and anion gap between HD SII and HD LII . Both immediate postdialysis and 30-minute postdialysis plasma urea concentrations were significantly higher for HD LII . Urea removal, creatinine removal, modified urea reduction ratio (mURR), single-pool Kt/V (spKt/V) and equilibrated Kt/V (eKt/V) were significantly greater for HD LII . Moreover, there was a good linear relationship between mURR for HD SII and HD LII . Similar findings were noted for both spKt/V and eKt/V. However, there were no differences between the two dialyses in urea reduction ratio, normalized protein equivalent of total nitrogen appearance and postdialysis urea rebound. Our findings suggest that there are differences in some dialysis indices and blood biochemistry parameters between HD SII and HD LII . Standardization of dialysis sessions (HD SII or HD LII ) for blood sampling schedules is needed to permit meaningful comparison of dialysis indices and biochemistry parameters within and between dialysis patients.