Protein Nitrogen Appearance Research Articles

Modified creatinine index as a marker of skeletal muscle mass in peritoneal dialysis patients.

Sarcopenia is common in peritoneal dialysis (PD) patients. Modified creatinine index (MCrI) by the Canaud's formula and single-pool Kt/V value is an accurate surrogate marker for muscle mass in hemodialysis patients. However, the method of calculation and validity of MCrI has not been tested in PD. In the exploratory cohort, we studied 138 consecutive patients converted from PD to hemodialysis. Their MCrI during PD, calculated by the Canaud's formula with total weekly Kt/V, and the conventional MCrI after conversion to HD, were compared by the Bland-Altman method. Their correlation with muscle mass as determined by bioimpedance spectroscopy and creatinine kinetic methods was explored. The result was then validated in a second cohort of 605 incident PD patients. In the exploratory cohort, the average bias of computing MCrI during PD and hemodialysis was 0.758mg/kg/day (95%CI -4.356 to 5.873mg/kg/day). The MCrI during PD significantly correlated with the muscle mass by creatinine kinetics (r=.684, P<.0001) and by bioimpedance spectroscopy (r=.641, P<.0001), but not with protein nitrogen appearance, overhydration, or adipose tissue mass, and the result was similar in the validation cohort. For incident PD patients, MCrI quartile was significantly associated with the risk of death from all cause in 12 months (Gray's test, P=.013) but not conversion to chronic hemodialysis (P=.14). In PD patients, MCrI computed by the Canaud's formula and total weekly Kt/V is a simple and reliable marker of skeletal muscle mass and may serve as a short-term prognostic indicator.

Association Between Peritoneal Glucose Absorption, Lipid Metabolism, and Cardiovascular Disease Risk in Nondiabetic Patients on Peritoneal Dialysis

BackgroundExcessive sugar intake increases the energy metabolic burden and the risk of cardiovascular disease (CVD). Patients on peritoneal dialysis (PD) absorb much more glucose than the World Health Organization recommends, but the link to CVD is unclear. ObjectiveTo identify the association between peritoneal glucose absorption, lipid metabolism, and CVD. MethodsWe applied generalized additive mixed-effects and mixed-effects Cox proportional hazard models to evaluate the impact of peritoneal glucose absorption on lipid profiles and CVD risk. We performed subgroup analyses by using protein intake (normalized protein nitrogen appearance [nPNA] and normalized protein catabolic rate [nPCR] were used to assess protein intake) and high-sensitivity C-reactive protein (hs-CRP). ResultsAfter multivariable adjustment, peritoneal glucose absorption per 10 g/d increase was associated with an increase in cholesterol of 0.145 (95% confidence interval [CI]: 0.086–0.204) mmol/L. No link with the total risk of CVD was observed; however, protein intake and hs-CRP levels affected the relationship between glucose absorption and CVD risk. Patients with values for nPNA and nPCR < 1.0 g/(kg∙d) were associated with a lower risk of CVD (hazard ratio [HR] 95% CI 0.68 (0.46–0.98)) with glucose absorption per 10 g/d increase. While patients with hs-CRP levels ≥ 3 mg/d or values for nPNA or nPCR ≥ 1.0 g/(kg∙d) were associated with a higher risk of CVD (HR 95% CI 1.32 (1.07–1.63); 1.31 (1.02–1.68)) for glucose absorption per 10 g/d increase. ConclusionsOur study found a positive correlation between peritoneal glucose absorption and lipid profiles. Increased glucose absorption was associated with a lower risk of CVD in lower protein intake patients, and a higher risk of CVD in higher hs-CRP or protein intake levels in patients on PD.

Effect of intradialytic oral nutritional supplementation on nutritional markers in malnourished chronic hemodialysis patients: prospective randomized trial

Background and objectivesMalnutrition is prevalent in chronic hemodialysis (HD) patients. It increases mortality and negatively affects quality of life. This study aimed to assess the effect of intradialytic oral nutritional supplement (ONS) on nutritional markers in chronic HD patients with protein energy wasting (PEW).MethodsThis 3-month prospective, open-label, randomized controlled trial included 60 chronic HD patients with PEW. The intervention group (30 patients) received intradialytic ONS and dietary counseling, whereas the control group (30 patients) received only dietary counseling. Nutritional markers were measured at the beginning and end of the study.ResultsThe mean age of the patients was 54 ± 12.7 years, and that of the HD vintage was 64 ± 49.3 months. Compared to the control group, the intervention group showed a significant increase in serum albumin (p < 0.001), prealbumin (p < 0.001), cholesterol (p = 0.016), body mass index (BMI) (p = 0.019), serum creatinine/body surface area (BSA) (p = 0.016), and composite French PEW score (p = 0.002), as well as a significant decrease in high-sensitivity C-reactive protein (hs-CRP) (p = 0.001). The total iron binding capacity, normalized protein nitrogen appearance, and hemoglobin levels increased significantly in both groups.ConclusionIntradialytic ONS and dietary counseling for three months were more effective than dietary counseling alone in terms of improving nutritional status and inflammation in chronic HD patients, as evidenced by increases in serum albumin, prealbumin, BMI, serum creatinine/BSA, composite French PEW score, and a decrease in hs-CRP.

Comparison of frailty, sarcopenia and protein energy wasting in a contemporary peritoneal dialysis cohort.

More elderly frail patients are now treated by peritoneal dialysis (PD). Frailty, sarcopenia and protein energy wasting (PEW) are all associated with increased mortality. Simple screening tools are required to identify patients to allow for interventions. As such, we wished to review the prevalence of frailty and compare frailty with sarcopenia and PEW in a contemporary PD population. We used the Clinical Frailty Score (CFS) to determine frailty, bio-impedance body composition and hand grip strength (HGS) to determine sarcopenia and combining laboratory, body composition and protein nitrogen appearance rate (PNA) to assess PEW. Records of 368 PD patients, 61% male, mean age 60.9 ± 16.1 years, body mass index (BMI) 26.2 ± 5.1 kg/m2 were reviewed, with 71 classified as frail (19.3%; CFS > 4), and frailty associated with age (odds ratio (OR) 1.047, 95% confidence interval (CL) 1.01-1.085, p = 0.012), Stoke-Davies co-morbidity (OR 1.808, 95%CL 1.129-2.895, p = 0.014) and negatively with HGS (OR 0.906, 95% CL 0.897-0.992, p = 0.033); 17.7% met muscle loss and HGS criteria for sarcopenia, with fair agreement with frailty (kappa 0.24 (CL 0.09-0.38)). Only two patients (0.5%) met all four criteria for PEW, 26.1% met the reduced BMI criteria, 4.6% the serum albumin, 32.9% the PNA and 39.4% the reduced muscle mass. HGS correlated with lean muscle mass (r 2 = 0.42, p < 0.001). Using the CFS, 19.3% of patients were classified as frail, compared to 17.7% with sarcopenia and <1% with PEW. The CFS requires no special equipment or laboratory tests and was associated with age, co-morbidity and HGS weakness.

Changes in blood glucose and lactate concentrations with hemodialysis.

Blood glucose concentrations are recognized to vary during hemodialysis (HD), with hypoglycemia reported with glucose-free dialysates. As glucose can be converted to lactate, and conversely lactate to glucose, we wished to study factors associated with peri-dialytic changes in blood glucose. We prospectively collected data including patient profile, dialysis prescription, hemodynamic parameters, medications, dialysis adequacy and monthly blood tests for three consecutive months. All patients used a 100mg/dl glucose dialysate. Linear mixed model, general estimated equation and binary logistic regression were used for analysis. We studied 157 sessions in 55 patients, median age 67.1 (58.5-72.6) years, 67% male, 71% diabetic, 40% prescribed insulin, dialysis vintage 20.4 (10.7-57.7) months. Mean single pool Kt/Vurea and normalized protein nitrogen appearance rate (nPNA) were 1.70±0.34 and 1.01±0.30g/kg/day respectively. Hypoglycemia (<70mg/dl) occurred during 10 sessions (6.4%). 25% of non-diabetes experienced hypoglycemia. The % change in peri-dialytic blood glucose was associated with the % change in lactate (estimate of fixed effect=0.23 p<0.001) and pre-HD glucose (estimate of fixed effect=0.09, p<0.001). The fall in glucose was not associated with urea clearance, consumption of food, administration of insulin or antidiabetic medications, nPNA, body mass index, or pyridoxine concentrations. Peri-dialytic hypoglycemia cannot simply be explained by dialyzer clearance, as the corresponding fall in lactate would potentially suggest increased gluconeogenesis. Despite using a glucose containing dialysate, asymptomatic hypoglycemia occurred in 6.4% of sessions, suggesting a role for peri-dialytic blood glucose monitoring and avoiding fasting during dialysis.

Consequences of Interdialytic Weight Gain Among Hemodialysis Patients.

BackgroundInterdialytic weight gain (IDWG) is a marker of higher pre-dialysis blood pressure, nutrition, and survival in hemodialysis (HD) patients. However, this relationship is incompletely characterized. In this study, we seek to define the association of IDWG/dry weight x100 (IDWG%) on blood pressure (BP), and the nutritional status of an HD population.Material and MethodsThis study was performed on 300 HD patients. The data was collected over four weeks, including total IDWG, IDWG%, and blood pressure. Normalized protein nitrogen appearance (nPNA), and serum albumin were used as markers of nutritional status. Participants were divided into three groups according to the mean of the IDWG% between two sessions of HD (group A < 3%, group B = 3% - 3.9%, and group C ≥ 4%); they were then compared on various aspects. Student t-test, analysis of variance (ANOVA), and linear regression analysis were used as statistical tools.ResultsThe mean (± standard deviation (SD)) age was 61.7 ± 14.2 years with 57.7% of the patients being male and 42.3% being female. The mean IDWG% for the whole studied population was 3.72% ± 1.73%. Between these three groups, a higher IDWG% was associated with younger males (p = 0.032), lower dry weight (p = 0.009), and longer duration on HD therapy (p = 0.009). IDWG% was directly associated with lower pre-dialysis serum sodium (p = 0.04), higher pre-dialysis serum creatinine (P = 0.002), and lower body mass index (BMI) (p= 0.003). Between these three groups, interdialytic variations in weight gain were not associated with increased BP. There was no significant difference between the three groups in terms of nPNA and serum albumin. ConclusionsThe most important associations of IDWG% are age, weight, pre-dialysis sodium, serum creatinine, and duration of dialysis (months). There was no association between IDWG% and increased systolic BP. IDWG% had no association with nutritional status.

The effect of protein-enriched snacks on serum albumin concentration in non-selected haemodialysis patients.

Serum albumin level is not only one of the protein-energy wasting criteria but also a powerful marker of mortality in patients on haemodialysis (HD) treatment. The study aimed to assess the effect of a protein-enriched snack given during HD treatment on serum albumin level. This prospective, single-centre, observational, non-randomized 16-month study was sub-divided into four 4-month periods.Patients on hemodialysis for more than three months and receiving a regular standard snack (8.8g of protein) during the HD session were included and assigned during four four-month periods to receive either the standard snack or a protein-enriched snack (28.7g). Patients were not selected based on nutritional criteria. Sixty-sixpatients completed the study. Serum albumin levels significantly increased, from 3.43 ± 0.28g/dl in the first period (standard snack) to 3.62 ± 0.32g/dl (p < 0.0001) in the second period (enriched snack). In the third period (standard snack), albumin levels remained stable (3.61 ± 0.35g/dl). After the fourth period (enriched snack), serum albumin levels further increased significantly(3.69 ± 0.30 g/dl;p = 0.05 and p = 0.007, respectively). Weight and normalized protein nitrogen appearance remained stable during the 16-month study period. This study suggests that the intake of a protein-enriched snack during HD treatment, independently from baselineserum albumin level, could significantly increase their serum albumin levels. Serum albumin level is a powerful predictor of mortality; therefore, this simple and effective action could be of real interest to improve patients' outcomes.

Association between Serum Uric Acid Levels, Nutritional and Antioxidant Status in Patients on Hemodialysis.

Purpose: To determine the relationship between uric acid (UA) and nutritional and antioxidant status in hemodialysis (HD) patients, given that hyperuricemia could be an indicator of good nutritional status possibly because of the antioxidant properties of UA. Methods: Cross-sectional study with 93 patients on HD. Hyperuricemia was considered as UA ≥6.0 mg/dL in females and ≥7.0 mg/dL in males. Nutritional variables were registered. Blood samples were taken before the dialysis session to determine oxidative damage as plasma malondialdehyde (MDA) content, and antioxidant capacity measuring 2,2-diphenyl-piclrylhidrazil radical (DPPH●) scavenging activity and oxygen radical absorbance capacity (ORAC) value. Results: Patients with hyperuricemia had higher creatinine (11.9 vs. 10.5 mg/dL; p = 0.004), potassium (5.5 vs. 5.0 mg/dL; p = 0.014) levels; phase angle (5.8 vs. 4.9; p = 0.005), protein consumption (normalized protein nitrogen appearance, nPNA, 1.03 vs. 0.83; p = 0.013) than normouricemic patients. DPPH● scavenging activity was higher in hyperuricemic subjects (1.139 vs. 1.049 mM Trolox equivalents; p = 0.007); likewise, hyperuricemic subjects had less oxidant damage measured by MDA (10.6 vs. 12.7 nmol/mL; p = 0.020). Subjects with normouricemia were at higher risk of having a reactance to height (Xc/H) ratio less than 35 (OR 2.79; 95% CI, 1.1–7.017, p = 0.028); nPNA < 1.0 (OR 3.78; 95% CI, 1.4–10.2, p = 0.007), diagnosis of cachexia (OR 2.95; 95% CI, 1156–7.518, p = 0.021), potassium levels <5 (OR 2.97; 95% CI, 1.136–7.772, p = 0.023) and PA < 5.5° (OR 3.38; 95% CI, 1.309–8.749, p = 0.012.) Conclusions: Patients with hyperuricemia had higher antioxidant capacity and better nutritional status. Purines and protein restrictions in HD patients with hyperuricemia need to be reviewed individually for each patient. More studies are needed to stablish a cut point of UA levels in renal population.

Addendum Regarding “Routine Kt/V and Normalized Protein Nitrogen Appearance Rate Determined From Conductivity Access Clearance With Infrequent Postdialysis Serum Urea Nitrogen Measurements” (Am J Kidney Dis. 76[1]:22-31)

Addendum Regarding “Routine Kt/V and Normalized Protein Nitrogen Appearance Rate Determined From Conductivity Access Clearance With Infrequent Postdialysis Serum Urea Nitrogen Measurements” (Am J Kidney Dis. 76[1]:22-31)

Integrating the Surprise Question, Palliative Care Screening Tool, and Clinical Risk Models to Identify Peritoneal Dialysis Patients With High One-Year Mortality

ContextUniversal screening to identify vulnerable patients who may receive limited benefits from life-sustaining treatments can facilitate palliative care in dialysis populations. ObjectivesWe aimed to develop prediction models for one-year mortality in peritoneal dialysis (PD) patients. MethodsThis prospective cohort study included 401 adult Taiwanese prevalent PD patients (average age 56.2 ± 14 years). In addition to obtaining clinical characteristics and laboratory data, the primary care nurses evaluated the surprise question (SQ) and palliative care screening tool (PCST) for each patient in March 2015. Multivariate logistic regression models were conducted to predict the primary outcome of one-year all-cause mortality. ResultsThere were 34 (8.5%) patients who died during the first year of follow-up. Patients allocated to the not surprised group according to the SQ and those who received a score of ≥4 on the PCST had increased odds of death (odds ratio 24.68 [95% CI 10.66–57.13] and 12.18 [95% CI 5.66–26.21], respectively). We also developed a clinical risk model for one-year mortality that included sex, dialysis vintage, coronary artery disease, malignancy, normalized protein nitrogen appearance, white blood cell count, and serum albumin and sodium levels. Integrating the SQ, PCST, and clinical risk model exhibited good discrimination with an area under the receiver operating characteristic curve of 0.95. Kaplan-Meier analysis showed worse survival in high-risk patients predicted by the integrated model (log-rank P < 0.001). ConclusionScreening with the use of the integrated measurement can identify high-risk PD patients. This approach may facilitate palliative care interventions for at-risk subpopulations.

Routine Kt/V and Normalized Protein Nitrogen Appearance Rate Determined From Conductivity Access Clearance With Infrequent Postdialysis Serum Urea Nitrogen Measurements

Conventional monitoring of hemodialysis dose is implemented using urea kinetic modeling based on single-pool Kt/V, which requires both pre- and postdialysis serum urea nitrogen (SUN) measurements. We compared this conventional approach to one in which Kt/V is calculated using conductivity clearance, thereby reducing the need for regular postdialysis SUN measurements. Comparative study of 2 diagnostic tests. Prevalent patients receiving maintenance hemodialysis for at least 2 years for whom both urea reduction ratio (URR) and average conductivity clearance (Kecn) were measured. During the initial 8 months (baseline interval), average Kecn and URR were used to calculate a median patient-specific, modeled, calibration solute distribution volume (Vcal). During months 9 to 16 (period 1) and 17 to 24 (period 2), Kt/V was conventionally computed using URR and also by a new method using Vcal and Kecn without postdialysis SUN values. We examined the percentage error between these 2 methods of calculating Kt/V. Concordance between the 2 methods of calculating Kt/V. Among 1,093 patients, mean individual-level median single-pool Kt/V values derived using the conventional method during the baseline interval, period 1, and period 2 were 1.62±0.24 (SD), 1.66±0.24, and 1.67±0.24, respectively. During periods 1 and 2, patient-level median Kt/V values derived using Kecn were 1.64±0.24 and 1.65±0.24, respectively. Percent differences between patient-level median values of Kt/V (conductivity minus conventional URR methods) were-0.63%±7.7% and-0.75%±8.4% for periods 1 and 2. Normalized protein nitrogen appearance were comparable between the 2 methods. Data were collected over 2 years. Study was limited to in-center hemodialysis patients dialyzed 3 times per week. Dialysis session length was not adjusted for treatment interruptions. A new method of calculating Kt/V based on Kecn that requires fewer postdialysis SUN measurements provided diagnostic data comparable to those from conventional use of URR and has the potential to avoid errors related to postdialysis blood sampling and measurement.

Dietary intake of tyrosine and phenylalanine, and p-cresyl sulfate plasma levels in non-dialyzed patients with chronic kidney disease.

ABSTRACTBackground: Patients with chronic kidney disease (CKD) present an imbalance of the gut microbiota composition, leading to increased production of uremic toxins like p-cresyl sulfate (PCS), product from bacterial fermentation of the amino acids tyrosine (Tyr) and phenylalanine (Phe) from the diet. Thus, diet may be a determinant in the uremic toxins levels produced by the gut microbiota. The aim of this study was to evaluate the possible relationship between Tyr and Phe intake and PCS plasma levels in non-dialysis CKD patients.Methods: Twenty-seven non-dialysis CKD patients (stages 3 and 4) without previous nutritional intervention were evaluated. The dietary intake was evaluated using a 24-hour recall, 3-day food record and protein intake was also estimated by Protein Nitrogen Appearance (PNA). The plasma levels of PCS were measured using reverse phase high performance liquid chromatography.Results: The evaluated patients (GRF, 34.8 ± 12.4 mL/min, 54.2 ± 14.3 years, BMI, 29.3 ± 6.1 kg/m2) presented mean protein intake of 1.1 ± 0.5 g/kg/day), Tyr of 4.5 ± 2.4 g/day and Phe of 4.6 ± 2.5 g/day. PCS plasma levels (20.4 ± 15.5 mg/L) were elevated and positively associated with both, Tyr (r = 0.58, p = 0.002) and Phe intake (r = 0.53, p = 0.005), even after adjustments for eGFR and age.Conclusion: This study suggests that the diet is an important modulator of the uremic toxins plasma levels produced by the gut microbiota, in non-dialysis CKD patients.

Fatigue in Peritoneal Dialysis Patients and an Exploration of Contributing Factors: A Cross-Sectional Study

ContextFatigue is a common and detrimental symptom in dialysis patients; however, our understanding of it and investigation of its contributing factors is still very limited, especially in peritoneal dialysis (PD) patients. ObjectivesTo assess fatigue in PD patients and identify contributing factors. MethodsOne hundred eight PD patients in a comprehensive hospital in China were recruited. The fatigue severity of the participants was assessed using the Chalder Fatigue Scale 11. Demographic factors and results of physiological tests were collected. Quality of sleep, mental health, and social support were assessed with the Pittsburgh Sleep Quality Index, Symptom Checklist 90, and Social Support Rating Scale, respectively. Multiple linear regression models were conducted with candidate variables with a P-value of less than 0.1 on univariate analysis and variables that were clinically relevant to identify contributing factors for fatigue. ResultsThe fatigue level in PD patients was significantly higher than the community population, and 78.7% of them were suffering from fatigue. The factors that were significantly associated with fatigue were quality of sleep, normalized protein nitrogen appearance, transferrin, alkaline phosphatase, and total cholesterol (adjusted R squared 0.86). Among them, quality of sleep, transferrin, alkaline phosphatase, and total cholesterol were significant contributors for physical fatigue, whereas the quality of sleep and normalized protein nitrogen appearance were contributing factors for mental fatigue. ConclusionFatigue is a common symptom in PD patients, suggesting that increased awareness of this symptom is required. The identification of correlates by extensive exploration of multidimensional factors in this study may help practitioners to identify patients at higher risk and to develop a multidimensional and targeted intervention plan.

Sodium loss, extracellular volume overload and hypertension in peritoneal dialysis patients treated by automated peritoneal dialysis cyclers.

Achieving sodium balance is important for peritoneal dialysis patients, as sodium excess may lead to hypertension and extracellular water expansion. We wished to determine whether greater sodium removal had adverse consequences. We calculated 24-h urinary and peritoneal sodium losses in peritoneal dialysis patients treated by automated cyclers, when attending for peritoneal membrane and bioimpedance assessments. We reviewed 439 peritoneal dialysis patients, 56.7% male, average age 54.6 years, median sodium loss 110 (68-155) mmol/day. Sodium loss was strongly associated with urine volume, r = 0.37, protein nitrogen appearance rate, r = 0.29, and body cell mass, r = 0.21, all p < 0.001. We found no association with blood pressure or anti-hypertensive medication prescription, or extracellular water. On multivariable logistic regression analysis, sodium loss was associated with greater urine output, odds ratio 1.001, 95% confidence interval 1.00-1.001, p < 0.001, and protein nitrogen appearance (odds ratio 1.023, confidence interval 1.006-1.04), p = 0.008. Adjusting for body weight, sodium loss was associated with urine output (odds ratio 1.001, confidence interval 1.001-1.002, p < 0.001), and negatively with body fat index (odds ratio 0.96, confidence interval 0.93-0.99, p = 0.008) and co-morbidity grade (odds ratio 0.58, confidence interval 0.36-0.39, p = 0.023). Heavier peritoneal dialysis patients with greater estimated dietary protein intake (protein nitrogen appearance), those with greater residual renal function and peritoneal clearances, along with lower co-morbidity, had greater daily sodium losses. Adjusting for body weight, then sodium losses were greater with higher daily urine output, and lower in patients with proportionately more body fat and co-morbidity. Sodium losses would appear to primarily determined by body size and not associated with hypertension or extracellular water expansion.

High rates of protein intake are associated with an accelerated rate of decline of residual kidney function in incident peritoneal dialysis patients.

Preservation of residual kidney function (RKF) is a relevant objective in peritoneal dialysis (PD) patients. The influence of dietary protein intake (PI) on this variable has not been adequately investigated. Following an observational design, we studied 336 patients incident on PD, with a minimum follow-up of 6 months. The main study variable was the mean PI [normalized rate of protein nitrogen appearance (nPNA)] during the first 4 months on PD. The main outcome variables were the absolute rate of decline of RKF and the proportion of patients presenting a >50% decay of their RKF during the first year of follow-up. We applied univariate and multivariate strategies of analysis, taking into consideration the main control variables bearing a correlation with nPNA and/or RKF. Mean nPNA (first 4 months) was 1.23 ± 0.33 g/kg/day, while the overall rate of decline of RKF was -0.13 ± 0.29 mL/min/month; 69 patients (25.1%) had lost >50% of their initial RKF by the end of the first year. Univariate analysis disclosed consistent associations between the main study variable on one hand and baseline RKF (r = 0.32, P < 0.0005) and its rate of decline (r = -0.23, P < 0.0005) on the other. The latter two variables were also significantly correlated (r = -0.36, P < 0.0005). Multivariate analysis identified mean nPNA as an independent predictor of the rate of decline of RKF [odds ratio 1.09 per 0.10 g/kg/day, 95% confidence interval (CI) 0.99-1.19, P = 0.058] and, in particular, of the probability of losing >50% of the baseline RKF during the first year of treatment (odds ratio 1.15 per 0.10 g/kg/day, 95% CI 1.04-1.27, P = 0.006). Higher rates of PI during the first months of therapy are associated with a faster decline of RKF among patients incident on PD. Our results underline the convenience of keeping an adequate balance between sufficient protein ingestion, to prevent malnutrition and wasting, and sensible restriction in stable, adequately nourished individuals with rates of intake in the higher range or above-recommended allowances.

Influence of dietary protein intake on body composition in chronic kidney disease patients in stages 3–5: A cross-sectional study

IntroductionA controlled protein intake has shown beneficial effects to preserve renal function and nutritional status in chronic kidney disease (CKD) patients. This study aimed to analyze usual dietary protein intake and its potential contribution to body composition in CKD patients in stages 3–5. MethodCross-sectional study in 134 CKD patients in stages 3–5 (mean e-GFR: 19.4±8.7ml/min/1.73m2; males 68.7% and primary CKD etiology was diabetes mellitus, 35.8%). Demographic, clinical and nutritional parameters were evaluated. Normalized protein nitrogen appearance (nPNA), was used as a surrogate marker of dietary protein intake. The sample was classified into three nPNA groups (Gn): G1: <0.8g/kg/day; G2: 0.8–1g/kg/day and, G3: ≥1g/kg/day. Assessment of nutritional status using the malnutrition-inflammation score (MIS), anthropometric measures and laboratory parameters. Analysis of body composition and hydration status by bioelectrical impedance analysis (BIVA-101-RJL system). Statistical analysis by SPSS v.20. ResultsOverall mean nPNA values were 0.91±0.23g of protein/kg BW/day and only 32.1% had a dietary protein intake <0.8g of protein/kg BW/day. Most of the CKD patients (65.5%) were in stages 4 or 5. Prevalence of protein–energy–wasting (PEW) syndrome measured by MIS was 15%. By analyzing differences between nPNA groups, body weight (BW), BMI and triceps-skinfold (TSF) thickness were significantly higher in the group with nPNA ≥1g/kg BW/day (G3), whereas a significant inverse relationship was found with the percentages of body cell mass (BCM%), fat-free mass (FFM%), muscle mass (MM%) and phase angle (PA) in the group with the lowest nPNA (G1). Analysis of gender among subjects showed significant differences with BW, FFM%, TSF and mid-arm muscle circumference (MAMC%). Linear regression analysis showed that resistance, BCM%, MM%, and serum albumin were significant predictors of nPNA as a surrogate marker of daily protein intake (R=0.51; R2=0.29; R2 adjusted=0.23; p<0.001). ConclusionControlled protein intake is one of the cornerstones of treatment in CKD patients. A low protein intake in patients with CKD stages 3 and 4–5 was associated with loss of muscle mass in the advanced-CKD unit. The loss of muscle mass appears as an early indicator of nutritional comprised. Factors such, elderly age and loss of eGFR, showed lower protein intake and were associated with muscle loss, especially in women. Further longitudinal studies are required to evaluate the contribution of different protein intakes to uremic symptoms, nutritional status, body composition and CKD progression.

Influence of dietary protein intake on body composition in chronic kidney disease patients in stages 3–5: A cross-sectional study

IntroductionA controlled protein intake has shown beneficial effects to preserve renal function and nutritional status in chronic kidney disease (CKD) patients. This study aimed to analyze usual dietary protein intake and its potential contribution to body composition in CKD patients in stages 3–5. MethodCross-sectional study in 134 CKD patients in stages 3–5 (mean e-GFR: 19.4±8.7ml/min/1.73m2; males 68.7% and primary CKD etiology was diabetes mellitus, 35.8%). Demographic, clinical and nutritional parameters were evaluated. Normalized protein nitrogen appearance (nPNA), was used as a surrogate marker of dietary protein intake. The sample was classified into three nPNA groups (Gn): G1: <0.8g/kg/day; G2: 0.8–1g/kg/day and, G3: ≥1g/kg/day. Assessment of nutritional status using the malnutrition-inflammation score (MIS), anthropometric measures and laboratory parameters. Analysis of body composition and hydration status by bioelectrical impedance analysis (BIVA-101-RJL system). Statistical analysis by SPSS v.20. ResultsOverall mean nPNA values were 0.91±0.23g of protein/kg BW/day and only 32.1% had a dietary protein intake <0.8g of protein/kg BW/day. Most of the CKD patients (65.5%) were in stages 4 or 5. Prevalence of protein–energy–wasting (PEW) syndrome measured by MIS was 15%. By analyzing differences between nPNA groups, body weight (BW), BMI and triceps-skinfold (TSF) thickness were significantly higher in the group with nPNA ≥1g/kg BW/day (G3), whereas a significant inverse relationship was found with the percentages of body cell mass (BCM%), fat-free mass (FFM%), muscle mass (MM%) and phase angle (PA) in the group with the lowest nPNA (G1). Analysis of gender among subjects showed significant differences with BW, FFM%, TSF and mid-arm muscle circumference (MAMC%). Linear regression analysis showed that resistance, BCM%, MM%, and serum albumin were significant predictors of nPNA as a surrogate marker of daily protein intake (R=0.51; R2=0.29; R2 adjusted=0.23; p<0.001). ConclusionControlled protein intake is one of the cornerstones of treatment in CKD patients. A low protein intake in patients with CKD stages 3 and 4–5 was associated with loss of muscle mass in the advanced-CKD unit. The loss of muscle mass appears as an early indicator of nutritional comprised. Factors such, elderly age and loss of eGFR, showed lower protein intake and were associated with muscle loss, especially in women. Further longitudinal studies are required to evaluate the contribution of different protein intakes to uremic symptoms, nutritional status, body composition and CKD progression.

A16521 Serum Advanced glycation end-products are associated with nutrition status but not aortic stiffness in end-stage renal disease

Objectives: Advanced glycation end-products (AGEs) are a heterogeneous group of uremic toxins, which are acquired via endogenous pathways and through absorption of AGE-modified peptides found in food. Through modification of extracellular structural proteins of the arterial wall, AGEs can lead to vascular stiffness. In this study, we aimed to examine the association of serum fluorescent AGEs with aortic stiffness (AS), tissue AGEs and protein intake in a cohort of subjects undergoing chronic hemodialysis. Methods: In 166 subjects with a mean age of 65 ± 15, 55% male, 48% diabetic and 59% with established cardiovascular disease, serum AGEs was determined by total serum and molecular weight based serum autofluorescence (HPLC), tissue levels of AGEs was measured by skin autofluorescence (AF), AS was measured by determination of carotid-femoral pulse wave velocity (cfPWV). Results: Despite higher levels of HbA1C in diabetic patients (0.063 ± 0.011 vs 0.052 ± 0.004, p = 0.001) and higher cfPWV (14.9 ± 3.7 vs 12.4 ± 3.8, p < 0.001), total serum AGEs was lower in diabetic subjects (3.47 ± 0.77 vs 2.97 ± 0.76, p < 0.001). There was a positive association between total serum AGEs and normalized protein nitrogen appearance rate in both diabetics (r = 0.337, p = 0.004) and non-diabetics (r = 0.362, p < 0.001). There were no correlations between skin AF and total serum AGEs or any of the fractions of molecular weight using various cut-offs (2, 5, 10 and 30 kd). In non-diabetics, there was a consistent negative association between serum AGEs and AS (even after adjustments for confounding factors), but there was not any associations between serum AGEs and AS in diabetics. Conclusion: Serum measurements of AGEs based on serum auto-fluorescence is better correlated to protein intake and is not associated with tissue levels of AGEs or AS.

Screening for muscle loss in patients established on peritoneal dialysis using bioimpedance.

LBMI was 9.7±1.9 kg/m2, mean age was 55.3±16.4 years, 53.1% were male, 33.7% were diabetic and 51% were Caucasoid. 98.5% of patients were classified as having sarcopenia based on LBMI cutoffs from NHANES data, whereas 28.8% had moderate and 6.3% severe sarcopenia using a grading correlated with functional disability. Lower muscle mass was associated with increasing co-morbidity (β=0.34, P=0.02) and age (β=0.01, P=0.006), and negatively with body mass index (β=-0.23, P<0.001), log serum creatinine (β=-0.231, P<0.001), normalised protein nitrogen appearance (β=-1.33, P<0.001) and log urine volume (β=-0.28, P=0.002). There was no association with duration of PD, dialysis prescription, residual renal function or solute clearances. There is currently no agreed universal definition for sarcopenia, and prevalence varied markedly depending on the scoring system. Prevalence was not associated with small solute clearances, but was associated with sex, age co-morbidity, BMI and ethnicity. There was an association with dietary protein intake and urine volume, which may allow for dietary interventions and strategies to preserve urine output to reduce muscle loss in PD patients.

Replacing Phosphorus-Containing Food Additives With Foods Without Additives Reduces Phosphatemia in End-Stage Renal Disease Patients: A Randomized Clinical Trial

The purpose of the study was to verify the effects of replacing phosphorus-containing food additives with foods without additives on phosphatemia in end-stage renal disease (ESRD) patients. Randomized clinical trial. Adult patients on hemodialysis for ≥6months at a single center. A total of 134 patients with phosphorus levels of >5.5mg/dL were included and were randomized into an intervention group (n=67) and a control group (n=67). The IG received individual orientation to replace processed foods that have phosphorus additives with foods of similar nutritional value without these additives. The CG received only the nutritional orientation given before the study. Clinical laboratory data, nutritional status, energy and protein intake, and normalized protein nitrogen appearance (nPNA) were evaluated at the beginning of the study and after 90days. There was no initial difference between the groups in terms of serum phosphorus levels, nutritional status, and energy intake. After 3months, there was a decline in phosphorus levels in the IG (from 7.2±1.4 to 5.0±1.3mg/dL, P<.001), but there was no significant difference in the CG (from 7.1±1.2 to 6.7±1.2mg/dL, P=.65). In the IG, 69.7% of the patients reached the serum phosphorus target of ≤5.5mg/dL; however, only 18.5% of the CG subjects reached this level (P<.001). At the end, there was no difference between the two groups in terms of nutritional status, energy intake, protein intake, and nPNA. The replacing phosphorus-containing food additives with foods without additives reduced serum phosphorus without interfering in the nutritional status of ESRD patients.