Protein Catabolic Rate Research Articles

Association of serum angiopoietin-2 with malnutrition, inflammation, atherosclerosis and valvular calcification syndrome and outcome in peritoneal dialysis patients: a prospective cohort study

BackgroundTo examine serum angiopoietin-2 (Angpt-2) in relation to malnutrition, inflammation, atherosclerosis and cardiac valvular calcification, so-called MIAC syndrome and its predictive role in outcomes of peritoneal dialysis (PD) patients.MethodsA prospective observational study was conducted in 324 chronic PD patients. Biochemical analysis was performed at baseline for serum angiopoietins, albumin and high sensitive C-reactive protein (hs-CRP) and echocardiography was done to detect cardiac valvular calcification. Primary study end points were fatal or nonfatal cardiovascular events and mortality.ResultsThe median of serum Angpt-2 levels was 5.44 ng/mL (interquartile range, 3.41–7.85). Across the three tertiles of serum Angpt-2, a significant trend effect was observed for body mass index, normalized protein catabolic rate, calcium × phosphorus product, hs-CRP, brain natriuretic peptide, lower-density lipoprotein cholesterol, left ventricular ejection fraction, total weekly urea clearance and residual renal function (all p < 0.05). Serum Angpt-2 showed a significant increase across the four groups of patients with increasing components of MIAC syndrome (p < 0.001). There were 77 deaths and 57 cardiovascular events. High serum Angpt-2 was an independent predictor of fatal and nonfatal cardiovascular events in PD patients (p = 0.02), however serum Angpt-2 was not an independent predictor of all-cause mortality (p = 0.3).ConclusionsSerum Angpt-2 showed close association with valvular calcification, atherosclerosis, inflammation and malnutrition, having significant independent prognostic value and is useful for cardiovascular event stratification in chronic PD patients. Angpt-2 might be a potential mediator of increased cardiovascular risk in patients undergoing PD treatment.

Serum levels of the adipokine zinc-alpha2-glycoprotein (ZAG) predict mortality in hemodialysis patients

Wasting has been associated with increased cardiovascular and all-cause mortality in chronic kidney disease (CKD). We investigated whether serum zinc-alpha2-glycoprotein (ZAG), a potent cachectic and lipid-mobilizing factor that is increased in patients with CKD, predicts clinical outcomes in patients on chronic hemodialysis. We quantified serum ZAG at baseline in a prospective cohort of 252 patients undergoing maintenance hemodialysis. Serum ZAG concentrations were inversely associated with serum albumin, creatinine, and triglycerides and, conversely, positively associated with age. Although ZAG is strongly linked to protein energy wasting (PEW) in patients with cancer, higher ZAG concentrations were not associated with PEW in our cohort. During a mean study follow-up of 954 days, 49 patients died and 62 patients experienced a cardiovascular event. Kaplan-Meier analysis revealed a significant correlation between serum ZAG concentrations and all-cause mortality and cardiovascular events. In separate multivariable Cox regression models, serum ZAG concentrations remained significantly associated with all-cause mortality and cardiovascular events after adjustment for demographic factors (age, sex, and dialysis vintage), metabolic parameters (serum albumin, prealbumin, triglycerides, cholesterol, normalized protein catabolic rate, and body mass index), and cardiovascular risk factors (diabetes, dyslipidemia, history of cardiovascular disease, smoking, and diuretic use as a proxy of residual renal function). Thus, serum ZAG appears to be a strong and independent predictor of mortality and cardiovascular events in patients with end-stage renal disease. Further studies are necessary to confirm this association and to elucidate the underlying mechanisms.

Eliminating the need for routine monthly postdialysis serum urea nitrogen measurement: A method for monitoring Kt/V and normalized protein catabolic rate using conductivity determined dialyzer clearance.

Many dialysis machines can compute dialyzer sodium clearances at multiple time points during a dialysis treatment using conductivity. For a given treatment, the average dialyzer sodium clearance (K), when combined with treatment time (t), and the estimated urea distribution volume (V, usually based on either anthropometry or bioimpedance), can be used to estimate Kt/V, an important measure of hemodialysis adequacy. While this conductivity-derived value for Kt/V correlates moderately with Kt/V calculated from predialysis and postdialysis serum urea nitrogen (SUN) values (urea reduction ratio, URR), the ultrafiltration volume, and session length it is, unfortunately, not sufficiently accurate to replace URR-based Kt/V. Here we underline the potential utility of an alternative method to estimate Kt/V (a variant of a technique originally proposed by Gotch and Levin and their colleagues) using conductivity-derived sodium clearance (K) that does not require routine measurement of the postdialysis SUN but which should closely track Kt/V computed in the usual fashion. The increased accuracy with the new method is explained by the use of a patient-specific value of V, which is an average value calculated from several dialysis sessions where both conductivity dialyzer clearance and predialysis and postdialysis SUN have been measured. Once this patient-specific conductivity/URR-based value for V has been determined, it can be used to calculate Kt/V for subsequent treatments in which conductivity-based dialyzer clearances are measured, but around which predialysis and postdialysis SUN values have not been obtained. (If the predialysis SUN values for such a subsequent treatment are also measured, then a normalized protein catabolic rate that closely tracks the value from conventional urea modeling, can also be determined.) By reducing the number of postdialysis SUN measurements needed to monitor hemodialysis adequacy this new method of estimating Kt/V by conductivity should save staff time and laboratory costs, increase patient and staff safety, and decrease error rates associated with improper postdialysis blood sampling technique.

Total weight loss obtained after 2 weeks of very low caloric diet is strongly associated with baseline (net) protein catabolic and glutamine production rates

Rationale: Obesity is a major healthcare problem and the need for management is well established. Very Low-Calorie Diet (VLCD) is often used for weight reduction, but large individual changes in weight loss between subjects have been observed. We studied whether the variation in weight loss after a VLCD among (morbidly) obese participants can be explained by individual differences in baseline protein and amino acid metabolism (so-called “metabolic phenotyping”).

The impact of residual renal function on quality of life in patients with peritoneal dialysis .

Residual renal function (RRF) is a crucial factor that plays an important role in peritoneal dialysis (PD) patients, but whether RRF influences the quality of life (QOL) of PD patients is still controversial. The aims of this study were to explore the effects of RRF on QOL in patients with continuous ambulatory peritoneal dialysis (CAPD) and analyze the related factors that might affect patients' QOL. All 120 adult patients in this study received regular CAPD treatment for at least 3 months. Patients were divided into two groups: an RRF group (residual glomerular filtration (rGFR) ≥ 1 mL×min-1×(1.73m2)-1) and a non-RRF group (rGFR ≥ 1 mL×min-1×(1.73m2)-1). The Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) was used as a reference to calculate the scores of CAPD patients for assessing their QOL. Multiple- and single-linear regression analysis was performed to analyze correlation degree of several SF-36-related indexes. The indexes of age, gender, cause of disease, complication, body mass index (BMI), systolic and diastolic blood pressure (SBP and DBP), hemoglobin (HB), cholesterol, triglycerides, high- and low-density lipoprotein, normalized protein catabolic rate (nPCR), and cardiothoracic ratio (CTR) showed no difference between the two groups (RRF and non-RRF). Comparing with RRF group, the patients without RRF showed a significant difference on indexes of PD duration, urine volume, ultrafiltration volume, dialysis dose, serum albumin, potassium, Kt/V (urea reduction ratio), creatinine, calcium, phosphate, C-reactive protein (CRP), and parathyroid hormone (PTH). Single-linear regression analysis that achieved total score of SF-36 showed no correlation with rGFR, but there was a correlation of SF-36 score with CRP, creatinine, CTR, albumin, and ultrafiltration volume. These results suggested that there was no correlation between RRF and QOL in CAPD patients, but chronic inflammation, fluid overload, and malnutrition were considered as the main factors that affect patients' QOL. .

Percorsi pratici per intraprendere un programma di dialisi monosettimanale combinato con una nutrizione ipoproteica personalizzata

The aim of this article is to provide detailed information to nephrologists on how to apply the combined diet dialysis program (CDDP) in selected patients. Patients are evaluated by urea nitrogen appearance, which allows the sustainability and compliance of patients on 0.6 g/kg per day low-protein diet to be verified by calculating the protein catabolic rate at a metabolic steady state. The combined action of nutrition and less frequent hemodialysis may preserve residual renal function with a further chance of achieving greater excretion of the protein-bound uremic toxins, thereby obtaining a positive phosphate balance. This paper describes all fundamental steps and calculations, although a greater clinical commitment is required to achieve a tailored therapeutic protocol such as Combined Diet Dialysis Program (CDDP).

Clinical efficacy and feasibility of whey protein isolates supplementation in malnourished peritoneal dialysis patients: A multicenter, parallel, open-label randomized controlled trial

Poor dietary intake is commonly associated with malnutrition in the dialysis population and oral nutritional supplementation is strategized to redress dietary inadequacy. Knowledge on clinical efficacy of whey protein supplementation (WPS) as an option to treat malnutrition in continuous ambulatory peritoneal dialysis (CAPD) patients is limited. This multicenter, parallel, open-label, randomized controlled trial investigated the clinical efficacy of WPS in 126 malnourished CAPD patients with serum albumin <40g/L and body mass index (BMI) <24kg/m2. Patients randomized to the intervention group (IG, n=65) received protein powder (27.4g) for 6 months plus dietary counseling (DC) while the control group (CG, n=61) received DC only. Anthropometry, biochemistry, malnutrition-inflammation-score (MIS), dietary intake inclusive of dialysate calories, handgrip strength (HGS) and quality of life (QOL) were assessed at baseline and 6 months. Clinical outcomes were assessed by effect size (Cohen's d) comparisons within and between groups. Seventy-four patients (n=37 per group) completed the study. Significantly more IG patients (59.5%) achieved dietary protein intake (DPI) adequacy of 1.2g/kg per ideal body weight (p<0.001) compared to CG (16.2%) although difference in the adequacy of dietary energy intake between groups was non-significant (p>0.05). A higher DPI paralleled significant increases in serum urea (mean Δ: IG=+2.39±4.36mmol/L, p=0.002, d=0.57 vs CG=-0.39±4.59mmol/L, p>0.05, d=0.07) and normalized protein catabolic rate, nPCR (mean Δ: IG=+0.11±0.14g/kg/day, p<0.001, d=0.63 vs CG=+0.001±0.17g/kg/day, p>0.05, d=0.09) for IG compared to CG patients. Although not significant, comparison for changes in post-dialysis weight (mean Δ:+0.64±1.16kg vs+0.02±1.36kg, p=0.076, d=0.58) and mid-arm circumference (mean Δ:+0.29±0.93cm vs-0.12±0.71cm, p=0.079, d=0.24) indicated trends favoring IG vs CG. Other parameters remained unaffected by treatment comparisons. CG patients had a significant decline in QOL physical component (mean Δ=-6.62±16.63, p=0.020, d=0.47). Using changes in nPCR level as a marker of WPS intake within IG, 'positive responders' achieved significant improvement in weight, BMI, skinfold measures and serum urea (all p<0.05), while such changes within 'negative responders' were non-significant (all p>0.05). A single macronutrient approach with WPS in malnourished CAPD patients was shown to achieve DPI adequacy and improvements in weight, BMI, skin fold measures, serum urea and nPCR level. CLINICAL TRIAL REGISTRY: www.clinicaltrials.gov (NCT03367000).

Impact du renforcement de la prise en charge nutritionnelle du patient en hémodialyse chronique par ajout d’œufs durs en collation

Denutrition for chronic hemodialysed patients is common and severe, often the first step of many complication and comorbidities. This work was aimed to study the impact of the adjunction of hard-boiled egg during six months, at the time of the hemodialysis session, if the classic nutritional support with oral nutritional supplements and intradialytic parenteral nutrition has failed. Required criteria were: Albuminemia, prealbuminemia and Moreau and Gaudry's score. Thirty-six patients have been included. During the six months, the following nutritional parameters have improved: Moreau and Gaudry's score decreased of 0.27, C reactive protein of 9.44 mg/L. Albuminemia improved of 3.53 g/L in average, pre-albuminemia of 0.2 g/L, and normalized Protein catabolic rate of 0.01 g/kg/day. Half of the patients were successful to stop the intradialytic parenteral nutrition. Protein adjunction with hard-boiled egg during chronic hemodialysis session, on top of the classic dietetic support has improved nutritional patient status.

Twice-Weekly Hemodialysis and Clinical Outcomes in the China Dialysis Outcomes and Practice Patterns Study

IntroductionIn China, a quarter of patients are undergoing 2-times weekly hemodialysis. Using data from the China Dialysis Outcomes and Practice Patterns Study (DOPPS), we tested the hypothesis that whereas survival and hospitalizations would be similar in the presence of residual kidney function (RKF), patients without RKF would fare worse on 2-times weekly hemodialysis.MethodsIn our cohort derived from 15 units randomly selected from each of 3 major cities (total N = 45), we generated a propensity score for the probability of dialysis frequency assignment, estimated a survival function by propensity score quintiles, and averaged stratum-specific survival functions to generate mean survival time. We used the proportional rates model to assess hospitalizations. We stratified all analyses by RKF, as reported by patients (urine output <1 vs. ≥1 cup/day).ResultsAmong 1265 patients, 123 and 133 were undergoing 2-times weekly hemodialysis with and without evidence of RKF. Over 2.5 years, adjusted mean survival times were similar for 2- versus 3-times weekly dialysis groups: 2.20 versus 2.23 and 2.20 versus 2.15 for patients with and without RKF (P = 0.65). Hazard ratios for hospitalization rates were similar for 2- versus 3-times weekly groups, with (1.15, 95% confidence interval = 0.66−2.00) and without (1.10, 95% confidence interval 0.68−1.79]) RKF. The normalized protein catabolic rate was lower and intradialytic weight gain was not substantially higher in the 2- versus 3-times weekly dialysis group, suggesting greater restriction of dietary sodium and protein.ConclusionIn our study of patients in China’s major cities, we could not detect differences in survival and hospitalization for those undergoing 2- versus 3-times weekly dialysis, regardless of RKF. Our findings indicate the need for pragmatic studies regarding less frequent dialysis with associated nutritional management.

Population Pharmacokinetics of Durvalumab in Cancer Patients and Association With Longitudinal Biomarkers of Disease Status.

The objectives of this analysis were to develop a population pharmacokinetics (PK) model of durvalumab, an anti‐PD‐L1 antibody, and quantify the impact of baseline and time‐varying patient/disease characteristics on PK. Pooled data from two studies (1,409 patients providing 7,407 PK samples) were analyzed with nonlinear mixed effects modeling. Durvalumab PK was best described by a two‐compartment model with both linear and nonlinear clearances. Three candidate models were evaluated: a time‐invariant clearance (CL) model, an empirical time‐varying CL model, and a semimechanistic time‐varying CL model incorporating longitudinal covariates related to disease status (tumor shrinkage and albumin). The data supported a slight decrease in durvalumab clearance with time and suggested that it may be associated with a decrease in nonspecific protein catabolic rate among cancer patients who benefit from therapy. No covariates were clinically relevant, indicating no need for dose adjustment. Simulations indicated similar overall PK exposures following weight‐based and flat‐dosing regimens.

Association between Increases in Normalized Protein Catabolic Rate and Increases in Creatinine Generation Rate in Dialysis Patients.

The older dialysis population is growing, and malnutrition and wasting syndrome are great concerns in this population. The management of these syndromes includes appropriate nutritional intake and physical activity. However, whether management in the form of an increase in protein intake has a beneficial effect on muscle mass has not been demonstrated. In this study, we investigated an association between changes of normalized protein catabolic rate (nPCR), as a proxy for protein intake and percent creatinine generation rate (%CGR), as a proxy for muscle mass in patients receiving hemodialysis. Multiple linear regression models were employed, and we included several sensitivity analyses. The results showed that increases in nPCR were associated with increases in %CGR. The association was stronger in patients with baseline %CGR levels below 100%. This was the first study to demonstrate that an increase in dietary protein intake might increase the muscle mass, but this study had certain limitations. Future interventional studies will be needed to investigate whether increases in protein intake have a beneficial effect on sarcopenia, protein-energy wasting, and frailty.

Cancer antigen 125 concentrations in patients on chronic peritoneal dialysis: Relationship with dialysis quality and membrane transport properties

The aim of this study was to evaluate longitudinal changes in drained dialysate cancer antigen 125 (dCA-125) levels and to assess relationships between dCA-125 and dialysis quality, peritoneal membrane transport rates, dialysate glucose load, peritonitis and use of erythropoiesis stimulating agents (ESA), angiotensin-converting-enzyme inhibitors (ACEi) and statins in patients with end-stage renal failure during the first 6 months of peritoneal dialysis (PD) treatment. This prospective study included 20 patients (11 males and 9 females; mean age 62.90?12.69 years) who were followed-up during the first 6 months of PD using conventional low pH glucose-based dialysis fluids. The concentration of dCA-125 was measured in all patients, and the peritoneal equilibration test (PET), peritoneal dialysis treatment adequacy (Kt/V), normalized protein catabolic rate (nPCR), and total, peritoneal and residual clearances of urea and creatinine were calculated. Information on peritonitis occurrence, the use of ESA, ACEi and statins were collected. Data were analyzed by the Mann-Whitney test, Wilcoxon matched pairs test and Spearman?s rank correlation. The concentration of dCA-125 significantly decreased during the follow-up (p=0.016). After 6 months of PD treatment, the concentration of dCA-125 decreased significantly (p=0.016) in all patients. The decrease was present in all patients, but was statistically significant in patients on ACEi therapy (p=0.006) and in patients not using statins (p=0.005) or ESA (p=0.012). No correlation was found between dCA-125 and glucose load, but a statistically significant negative correlation between dCA-125 and the PET for creatinine was observed (p=0.013). These findings challenge the role of dCA-125 in predicting mesothelial cell integrity in PD patients.

The Association between Intradialytic Hypertension and Metabolic Disorders in End Stage Renal Disease.

Background Intradialytic hypertension was associated with a high mortality risk. We examined the relationship between intradialytic hypertension and metabolic disorders in hemodialysis treatment patients. Methods We studied 76 patients in online hemodiafiltration. Dialysis adequacy was defined by Kt/V for urea. Normalized protein catabolic rate (nPCR), as a marker of protein intake, was calculated. Sodium removal was determined as percent sodium removal. Metabolic acidosis was determined by serum bicarbonate less than 22 mmol/L. Interdialytic urine volume more than 100 ml was recorded. Intradialytic hypertension was defined by an increase in systolic blood pressure equal to 10 mmHg from pre- to posthemodialysis. Arterial stiffness was assessed as carotid-femoral pulse wave velocity (c-fPWV) and carotid augmentation index (AIx). Chi-square tests and logistic regression analysis were applied for intradialytic hypertension prediction. Results Patients with intradialytic hypertension were older and had significantly lower hemoglobin, nPCR, urine output, and serum bicarbonate and significantly higher c-fPWV, though similar Kt/V for urea, than patients without intradialytic hypertension. They also had increased sodium removal and pulse pressure related to less urine output. Serum bicarbonate was inversely associated with c-fPWV (r = −0.377, p = 0.001). Chi-square test showed significant association between intradialytic hypertension and serum bicarbonate < 22 mmol/L (x2 = 5.6, p = 0.01), which was supported by an adjusted model. Conclusion The intradialytic hypertension was significantly associated with metabolic disorders including malnutrition/inflammation and uncontrolled metabolic acidosis in hemodialysis treatment patients. Severe metabolic acidosis may reflect sodium imbalance and hemodynamic instability of these patients resulting in volume overload and increased vascular resistance.

Relationship between serum uric acid and mortality among hemodialysis patients: Retrospective analysis of Korean end-stage renal disease registry data.

BackgroundIt is thought that hyperuricemia might lower the risk of mortality among hemodialysis patients, unlike in the general population, but the evidence is controversial. The aim of the current study was to evaluate the impact of serum uric acid level on the long-term clinical outcomes of hemodialysis patients in Korea.MethodsRetrospective analysis was performed on data from the End-Stage Renal Disease Registry of the Korean Society of Nephrology. This included data for 7,333 patients (mean age, 61 ± 14 years; 61% male) who received hemodialysis from January 2001 through April 2015. Initial laboratory data were used in the analysis.ResultsThe mean serum uric acid level in this study was 7.1 ± 1.7 mg/dL. Body mass index, normalized protein catabolic rate, albumin, and cholesterol were positively correlated with serum uric acid level after controlling for age and sex. After controlling for demographic data, comorbidities, and residual renal function, a higher uric acid level was independently associated with a significantly lower all-cause mortality (hazard ratio [HR], 0.90 per 1 mg/dL increase in uric acid level; 95% confidence interval [CI], 0.83–0.97; P = 0.008), but not cardiovascular mortality (HR, 0.90; 95% CI, 0.80–1.01; P = 0.078). Comparing uric acid levels in the highest and lowest quintiles, the HR for all-cause mortality was 0.65 (95% CI, 0.42–0.99; P = 0.046).ConclusionHyperuricemia was strongly associated with a lower risk of all-cause mortality, but there seems to be no significant association between serum uric acid level and cardiovascular mortality among Korean hemodialysis patients with end-stage renal disease.

Effects of Oral Nutritional Supplements on Mortality, Missed Dialysis Treatments, and Nutritional Markers in Hemodialysis Patients

Protein-energy wasting is common in end-stage renal disease patients undergoing dialysis and is strongly associated with mortality and adverse outcomes. Intradialytic oral nutritional supplements (ONS) reduce risk of mortality in these patients. Large studies characterizing the impact of ONS on other outcomes are lacking. We assessed the associations between administration of ONS and clinical and nutritional outcomes. Retrospective evaluation of a pilot program providing ONS to patients at a large dialysis organization in the United States. The pilot program provided ONS to in-center hemodialysis patients with serum albumin ≤3.5g/dL at 408 facilities. ONS patients were compared to matched controls with serum albumin ≤3.5g/dL, identified from facilities not participating in the ONS program (n=3,374 per group). Receipt of ONS. Death, missed dialysis treatments, hospitalizations, serum albumin, normalized protein catabolic rate, and postdialysis body weight were abstracted from large dialysis organization electronic medical records. There was a 69% reduction in deaths (hazard ratio=0.31; 95% confidence interval=0.25-0.39), and 33% fewer missed dialysis treatments (incidence rate ratio=0.77; 95% confidence interval=0.73-0.82) among ONS patients compared to controls (P<.001 for both). The effects of ONS on nutritional indices were mixed: serum albumin was lower, whereas normalized protein catabolic rate values, a surrogate for dietary protein intake, and postdialysis body weights were higher for ONS patients compared to controls during follow-up. Our evaluation confirmed the beneficial effects of ONS in reducing mortality and improving some indices of nutritional status for hypoalbuminemic hemodialysis patients. We also report the novel finding that ONS can reduce the number of missed dialysis treatments. These results support the use of intradialytic ONS as an effective intervention to improve the outcomes in hemodialysis patients with low serum albumin.

A Randomized, Double-Blind, Crossover Pilot Trial of Rice Endosperm Protein Supplementation in Maintenance Hemodialysis Patients

In maintenance hemodialysis (MHD) patients, low protein intake is associated with protein-energy wasting, a risk factor that affects outcome. However, increased protein intake may lead to hyperphosphatemia and hyperkalemia, which are also mortality risk factors. Here, we evaluated the safety and effects of purified rice endosperm protein (REP), which contains less phosphorus and potassium than soy and casein proteins, as a supplemental protein source for MHD patients. This randomized, double-blind, placebo-controlled, crossover pilot study of REP supplementation (5 g/day × 4 weeks) was carried out in 50 Japanese adult MHD patients (1 dropped out); the primary outcome was the change in the urea kinetic-based normalized protein catabolic rate (nPCR), an indicator of protein intake in MHD patients. Intention-to-treat analyses of 24 patients in the REP-first group and 25 in the placebo-first group showed that REP supplementation increased nPCR significantly by 0.07 g/kg/day (95% confidence interval, 0.03–0.11), whereas changes in serum phosphorus and potassium concentrations were not different from the placebo. REP supplementation did not show a significant effect on other nutritional or metabolic parameters and no specific complications. In conclusion, purified REP with efficient bioavailability may be safe and useful for dietary supplementation in MHD patients.

Dynamics of Nutritional Competence in the Last Year Before Death in a Large Cohort of US Hemodialysis Patients

Recently, a new Nutritional Competence Score (NCS) has been shown to associate with hospitalization and outcome in hemodialysis patients. The aim of this study was to investigate the dynamics, the individual components, and the impact of hospitalizations of this score's trajectory in the year before death. In addition, we investigated whether dynamics in the NCS add additional independent prognostic value over a single cross-sectional assessment. We included all Fresenius Medical Care North America patients who initiated hemodialysis between January 1, 2006, and December 31, 2011 with data on all 5 NCS components (serum albumin, creatinine, phosphate, equilibrated normalized protein catabolic rate, and interdialytic weight gain) in at least 1month. NCS was quantified monthly, and trajectories were compared between nonsurvivors and survivors across different dialysis vintage strata. Survivors and nonsurvivors were matched by dialysis vintage. The association of baseline NCS and NCS dynamics with mortality risk were assessed with Cox proportional hazards models. In this cohort of 110,794 patients, we found that across all vintage groups, NCS was lower in patients who died than in survivors. NCS was found to significantly decline before death, whereas survivors showed no decline in NCS. The rate of NCS decline before death was not materially influenced by hospitalization in the months before death. Cox models showed that NCS dynamics over time carry significant predictive power above a cross-sectional NCS assessment. There are distinct differences in NCS values and their trajectories between patients who die and vintage-matched controls. These differences may be able to be exploited for implementation of a routine, prospective monitoring tool for early detection of patients at increased risk of death. Prospective studies are required to validate such an approach.

Carbon, nitrogen and sulphur isotopic fractionation in captive juvenile hooded seal (Cystophora cristata): Application for diet analysis.

Intrinsic biogeochemical markers, such as stable isotope ratios of carbon, nitrogen and sulphur, are increasingly used to trace the trophic ecology of marine top predators. However, insufficient knowledge of fractionation processes in tissues continues to hamper the use of these markers. We performed a controlled feeding experiment with eight juvenile hooded seals (Cystophora cristata) that were held on a herring-based diet (Clupea harengus) for two years. Stable isotope ratios were measured via isotope ratio mass spectrometry in three of their tissues and related to values of these markers in their diet. Diet-tissue isotope enrichment (trophic enrichment factor, TEF) values between dietary herring and seal tissues for carbon (Δ13 C) were +0.7 ‰ for red blood cells, +1.9 ‰ for hair and +1.1 ‰ for muscle. The TEFs for nitrogen trophic (Δ15 N) were +3.3 ‰ for red blood cells, +3.6 ‰ for hair and +4.3 ‰ for muscle. For sulphur, the Δ34 S values were +1.1 ‰ for red blood cells, +1.0 ‰ for hair and +0.9 ‰ for muscle. These enrichment values were greater than those previously measured in adult seals. This increase may be related to the higher rate of protein synthesis and catabolism in growing animals. This study is the first report on sulphur isotope enrichment values for a marine mammal species.

MON-P124: Value of the Protein Catabolic Rate (PCR) As an Indicator of Protein Intake in Hemodialysis Patients (HDP) and Its Association with Anthropometric and Biochemical Parameters. Influence of inflammation

MON-P124: Value of the Protein Catabolic Rate (PCR) As an Indicator of Protein Intake in Hemodialysis Patients (HDP) and Its Association with Anthropometric and Biochemical Parameters. Influence of inflammation

Energy and Protein in Critically Ill Patients with AKI: A Prospective, Multicenter Observational Study Using Indirect Calorimetry and Protein Catabolic Rate.

The optimal nutritional support in Acute Kidney Injury (AKI) still remains an open issue. The present study was aimed at evaluating the validity of conventional predictive formulas for the calculation of both energy expenditure and protein needs in critically ill patients with AKI. A prospective, multicenter, observational study was conducted on adult patients hospitalized with AKI in three different intensive care units (ICU). Nutrient needs were estimated by different methods: the Guidelines of the European Society of Parenteral and Enteral Nutrition (ESPEN) for both calories and proteins, the Harris-Benedict equation, the Penn-State and Faisy-Fagon equations for energy. Actual energy and protein needs were repeatedly measured by indirect calorimetry (IC) and protein catabolic rate (PCR) until oral nutrition start, hospital discharge or renal function recovery. Forty-two patients with AKI were enrolled, with 130 IC and 123 PCR measurements obtained over 654 days of artificial nutrition. No predictive formula was precise enough, and Bland-Altman plots wide limits of agreement for all equations highlight the potential to under- or overfeed individual patients. Conventional predictive formulas may frequently lead to incorrect energy and protein need estimation. In critically ill patients with AKI an increased risk for under- or overfeeding is likely when nutrient needs are estimated instead of measured.