Protein Equivalent Of Nitrogen Appearance Research Articles

Cystatin C levels in functionally anephric patients undergoing dialysis: the effect of different methods and intensities.

Cystatin C, a low molecular weight protein, is produced by nucleated cells, filtered by glomeruli, and degraded by tubules at a constant rate. Its serum concentration has been proposed as a marker of GFR. Its size should make it dialyzable. It is hypothesized that serum cystatin C levels are influenced by the method and intensity of dialysis received. This is a cross-sectional pilot study of cystatin C in functionally anephric dialysis patients. It was measured predialysis in 14 patients on conventional (3 to 5 h, 3 x wk) hemodialysis; eight on nocturnal hemodialysis (three to seven nights, 6 to 8 h); three on daily hemodialysis (6 d, 1(1/2) to 2(1/2) h); and 10 on automated peritoneal dialysis. All had urea kinetic studies and values for single pool Kt/V (Sp Kt/V), standard weekly Kt/V (Std Kt/V), and protein equivalent of nitrogen appearance (nPNA; g/kg/d). C reactive protein (CRP; mg/L) and thyroid stimulating hormone (TSH; mIU/L) were measured as factors known to influence cystatin C. There was no correlation between cystatin C and Sp Kt/V, but there was a significant inverse linear correlation with Std Kt/V and there were significant differences between treatment modalities in cystatin C levels and in Std Kt/V. The estimation of cystatin C was reliable and stable over 3 to 6 wk and its levels uninfluenced by nPNA, CRP, or TSH. Serum cystatin C levels are influenced by the method and intensity of dialysis and may have a role in treatment adequacy monitoring.

The Protein Equivalent of Nitrogen Appearance in Critically Ill Acute Renal Failure Patients Undergoing Continuous Renal Replacement Therapy

To assess the nutritional status of critically ill patients with acute renal failure on continuous renal replacement therapy (CRRT) and their protein needs by estimating the protein equivalent of nitrogen appearance (PNA). Prospective, observational study. A 74-bed intensive care unit in a single tertiary care hospital. Twenty-five consecutive critically ill patients with acute renal failure on CRRT. The patients were studied over a period of 24 hours, at initiation on CRRT. The nutritional status was assessed by anthropometry and bioimpedance analysis. The PNA was estimated using the Bergstrom equation and PNA was normalized to body weight. The mean age was 58.2 +/- 17 years and 20 (80%) were male. The mean weight was 67 +/- 12 kg, body mass index was 25 +/- 3.5 kg/m(2), and triceps and subscapular skin fold thickness were 13 +/- 4.6 mm and 15 +/- 2.5 mm, respectively. Bioimpedance studies showed that the total body water was increased at 61.7 +/- 5.5% and body fat was 31.8 +/- 5.4%. The PNA was 103 +/- 35 g/day and normalized PNA was 1.57 +/- 0.4 g/kg/day. The mean protein intake was 0.56 +/- 0.38 g/kg/day, resulting in mean net negative protein balance of 1.0 +/- 0.6 g/kg/day. Malnutrition was uncommon in patients with acute renal failure at the time of initiation on CRRT, but their total body water was increased. They exhibited hypercatabolism and the mean normalized PNA was 1.57 g/kg/day. A large negative nitrogen balance was observed in them, since their protein intake was suboptimal.

Association Between Serum Albumin and Mortality in Dialysis Patients Is Partly Explained by Inflammation, and Not by Malnutrition

We investigated the effects of inflammatory and nutritional status on the association between serum albumin and mortality in hemodialysis (HD) and peritoneal dialysis (PD) patients. This was a prospective cohort study of incident dialysis patients starting HD or PD. Inflammation (C-reactive protein >or=5 or >or=10 mg/L), malnutrition (1 to 5 on the 7-point subjective global assessment [SGA]), and low protein intake (normalized protein equivalent of nitrogen appearance [nPNA] <0.99 g/kg/day) were measured at 3 months after the start of dialysis. The study involved 38 dialysis centers in The Netherlands. We ascertained all-cause mortality during the first 2 years after the start of dialysis. In total, 700 patients were included (mean SD age, 59 [+/-15] years; serum albumin, 3.3 (0.7) g/dL; 60% men; 454 starting HD, and 246 starting PD). The 2-year mortality was 21%. In HD patients, the mortality (hazard ratio [HR], with 95% confidence interval [95% CI]) per unit decrease in serum albumin (g/dL) was 1.47 (95% CI, 1.07 to 2.00). Adjustment for SGA did not decrease this risk, whereas adjustment for nPNA decreased the HR to 1.45 (95% CI, 1.06 to 1.97). The mortality risk decreased to 1.30 (95% CI, 0.95 to 1.78) after adjustment for inflammation, and did not further decrease after additional adjustment for SGA and nPNA. Additional adjustments for age, sex, and comorbidity decreased the HR to 1.09 (95% CI, 0.79 to 1.51). In PD patients, the effects of adjustments on the mortality risk of serum albumin (1.38; 95% CI, 0.87 to 2.20) were similar. In dialysis patients, a 1-g/dL decrease in serum albumin was associated with an increased mortality risk of 47% in HD patients and 38% in PD patients. These mortality risks were in part explained by the inflammatory pathway. The mortality risks associated with serum albumin were not a consequence of malnutrition, as measured with SGA and nPNA. These findings imply that nutritional status cannot be assessed with precision by the measurement of serum albumin in dialysis patients.

De Novo Hypokalemia in Incident Peritoneal Dialysis Patients: A 1-Year Observational Study

Hypokalemia occurs frequently in patients undergoing peritoneal dialysis (PD). However, the therapeutic strategy may differ from that of non-PD-related hypokalemia. We investigated clinical features and related factors of de novo hypokalemia in incident PD patients. We retrospectively enrolled 82 normokalemic patients starting PD at Gachon University Gil Hospital, Korea. The patients were divided into hypokalemia (K+<3.5 mEq/L) and normokalemia (3.5 mEq/L≤K+<5.5 mEq/L) groups based on the plasma potassium levels at month 13, and then clinical parameters including peritoneal function and adequacy tests and biochemical parameters were compared. Eight patients who showed hyperkalemia (K+≥5.5 mEq/L) at month 13 were excluded from our analyses. The incidence of hypokalemia in PD patients was 7.3% in a year. The de novo hypokalemia (n=6) and normokalemia (n=68) groups had no significant differences in baseline characteristics. The serum albumin levels and normalized protein equivalent of nitrogen appearance (nPNA) at month 1 were not significantly different between the two groups. At month 13, on the other hand, serum albumin levels and nPNA were significantly lower in the hypokalemia group (P=0.014; P=0.006, respectively). Kt/Vurea, residual renal function, dialysate-peritoneal creatinine ratio, and glucose load were not significantly different between the two groups. Hypokalemia occurring after initiation of PD may largely be associated with poor nutritional status.

Could Solutions Low in Glucose Degradation Products Preserve Residual Renal Function in Incident Peritoneal Dialysis Patients? A 1-Year Multicenter Prospective Randomized Controlled Trial (Balnet Study)

In vitro studies of peritoneal dialysis (PD) solutions demonstrated that a lactate-buffered fluid with neutral pH and low glucose degradation products (LF) has better biocompatibility than a conventional acidic lactate-buffered fluid (CF). However, few clinical trials have evaluated the long-term benefit of the biocompatible solution on residual renal function (RRF). To compare LF with CF, we performed a prospective, randomized study with patients starting PD. After 1-month run-in period, 91 new PD patients were randomized for 12 months of treatment with either LF (Balance: Fresenius Medical Care, Bad Homburg, Germany; n = 48) or CF (Stay Safe: Fresenius; n = 43). We measured RRF, acid-base balance, peritoneal equilibration test, and adequacy of dialysis every 6 months after the run-in period. After 12 months of treatment, the residual glomerular filtration rate (GFR) in patients using LF tended to be higher than that of patients on CF (p = 0.057 by repeated-measures analysis of variance). We observed a significant difference in the changes of residual GFR between the two groups (p = 0.009), a difference that was especially marked in the subgroup whose baseline residual GFR was more than 2 mL/min/1.73 m(2). In addition, serum total CO(2) levels were higher (p = 0.001) and serum anion gap was lower (p = 0.019) in the LF group. We observed no differences between groups for Kt/V, C-reactive protein, or normalized protein equivalent of nitrogen appearance. In incident PD patients with significant residual GFR, LF may better preserve RRF over a 12-month treatment period. Additionally, pH-neutral PD fluid may improve acid-base balance as compared with CF.

Long-Term Oral Sodium Bicarbonate Supplementation Does Not Improve Serum Albumin Levels in Hemodialysis Patients

Metabolic acidosis, a frequent event in hemodialysis patients, has been implicated as a potential cause of protein-energy malnutrition. Unfortunately, correction of metabolic acidosis by means of high bicarbonate concentration in the dialysate does not seem to lead to significant changes in nutritional parameters. The project was a single-arm, open-label, 12-month pilot study at a university-based tertiary care center aimed at evaluating whether correction of metabolic acidosis through long-term oral sodium bicarbonate supplementation improves serum albumin levels and other nutritional parameters in patients undergoing maintenance hemodialysis. Twenty highly acidotic hemodialysis patients patients were invited to consume an oral supplementation of sodium bicarbonate (1 g, thrice daily), for 12 months. Patients were followed at baseline and every month, until month 12. At each follow-up visit, dry body weight, BMI, blood pressure, presence of edema, venous bicarbonate, and serum albumin were measured. Total lymphocyte count, fasting total cholesterol and C-reactive protein were assessed every 2 months. At baseline and at 12 months, the subjective global assessment of nutritional status and the protein equivalent of nitrogen appearance normalized to actual body weight were determined. Plasma bicarbonate level rose from 18.1 ± 2.7 to 22.1 ± 4.5 mmol/l after 10 months (p = 0.001). Mean serum albumin levels were 3.8 ± 0.2 mg/dl at baseline and 3.9 ± 0.2 at the end of the study. Repeated measure ANOVA showed that there was no significant effect of bicarbonate treatment on serum albumin levels (p = 0.29), dry weight (p = 0.1), serum total cholesterol (p = 0.97), total lymphocyte count (p = 0.69), or C-reactive protein (p = 0.85). Mean subjective global assessment score was 4.53 ± 0.37 at baseline and 4.58 ± 0.54 at 12 months (p = 0.1). Mean nPNA (g/kg/day) was 0.86 ± 0.05 at baseline and 0.85 ± 0.08 at month 12. The present study demonstrates that long-term oral sodium bicarbonate at the dose of 1 gram thrice daily has no significant effect on nutritional status of HD patients.

Resting Energy Expenditure in Peritoneal Dialysis Patients

This study aimed to evaluate whether resting energy expenditure (REE) of patients undergoing peritoneal dialysis (PD) therapy differs from that of healthy individuals, as well as to investigate the factors associated with REE in this sample of patients. Cross-sectional study. Dialysis Unit of the Nephrology Division, Federal University of Sao Paulo-Oswaldo Ramos Foundation, Brazil. The study examined the REE of 37 patients (20 males, age 44.5 +/- 13 years) undergoing PD therapy. Only patients older than 18 years, on PD for at least 3 months, without catabolic illness, and with normal thyroid function were included. Patients were pair matched for age and gender with 37 healthy individuals. REE was measured by indirect calorimetry. Body composition was assessed by dual-energy x-ray absorptiometry in the patients and by bioelectrical impedance in the healthy individuals. The REE of PD patients was similar to that of pair-matched controls (1372 +/- 266 and 1453 +/- 252 kcal/day respectively, p = 0.13) even when adjusted for lean body mass and gender (p = 0.56). The REE of PD patients was positively correlated with lean body mass (r = 0.60, p < 0.01), fat mass (r = 0.43, p < 0.01), body mass index (r = 0.60, p < 0.01), serum glucose (r = 0.36, p < 0.05), and protein equivalent of nitrogen appearance (PNA; r = 0.42, p < 0.01). There were no correlations between REE and glucose absorption, dialysis-related parameters, C-reactive protein, and energy or protein intake by 3-day food diary. In the multiple linear regression analysis, using REE as the dependent variable, the final model showed that lean body mass and female gender were determinants of REE in PD patients (R(2) = 0.44). When separate analysis by gender was performed, REE correlated directly with body fat in female patients (r = 0.70, p < 0.01) but not in male patients (r = 0.29, p = 0.21). On the other hand, lean body mass was significantly correlated with REE in male patients (r = 0.78, p < 0.01) but not in female patients (r = 0.47, p = 0.06). This study showed that REE of PD patients did not differ from that of healthy individuals. The strong association between body fat and REE in female patients remains to be further investigated.

Stability of nutritional parameters during a 5‐year follow‐up in patients treated with sequential long‐hour hemodialysis

Progressive nutritional impairment has been recently reported during conventional hemodialysis (HD) treatment. We studied the nutritional parameters during a 5-year follow-up in HD patients. Thirty-three patients (15F/18M; 65 years old at the study start) filled out a 3-day food questionnaire once a year between 1995 and 1999 (study group). Twenty patients, who did not fill out the food records during this period served as a control group (control group). The food record was run by the renal dietician using a dedicated software, providing daily energy and protein intakes (DEI and DPI). Serum albumin, normalized protein equivalent of nitrogen appearance (nPNA), and postdialysis body weight (BW) at the time of food record were collected in the study group and from the patient chart in the control group. The energy intake in the study group and the protein intake in both groups were close to the recommended intakes in ESRD patients. Protein intake assessed from food questionnaire or from urea kinetics were not statistically different. Using ANOVA for repeated measures, no difference along the 5 years was found for daily energy intake, daily protein intake, nPNA, and BW in the study group. The BW and nPNA remained stable in the control group. Hence, this study does not confirm the progressive nutritional impairment reported in the HEMO study, whereas the patients' age and vintage are largely higher in the present study. The role of a large dialysis dose in maintaining nutritional status in HD patients is discussed.

The Ratio of Extracellular Fluid to Total Body Water and Technique Survival in Peritoneal Dialysis Patients

Patients receiving peritoneal dialysis experience a high technique failure rate and are often overhydrated. We examined whether an increased extracellular fluid volume (VECF) as a proportion of the total body water (VTBW) predicted technique survival (TS) in a prevalent patient cohort. The VECF and VTBW were estimated by multiple-frequency bioelectric impedance in 59 prevalent peritoneal dialysis patients (median time on dialysis 14 months). Demographic, biochemical (albumin, C-reactive protein, and ferritin), and anthropometric data, forearm muscle strength, nutritional score by three-point Subjective Global Assessment, residual renal function, dialysate-to-plasma (D/P) creatinine ratio, total weekly Kt/V urea, total creatinine clearance, normalized protein equivalent of nitrogen appearance, and midarm muscle circumference were also assessed. Technique survival was determined at 3 years, and significant predictors of TS were sought. In patient groups defined by falling above or below the median value for each parameter, only residual renal function (p = 0.002), 24-hour ultrafiltrate volume (p = 0.02), and VECF/VTBW ratio (p = 0.05) were significant predictors of TS. Subjects with a higher than median VECF/VTBW ratio had a 3-year TS of 46%, compared to 78% in subjects with a lower than median value. In multivariate analysis, systolic blood pressure and VECF/VTBW ratio (both p < 0.05) were significant predictors of TS. C-reactive protein approached significance. Increased ratio of extracellular fluid volume to total body water is associated with decreased TS in peritoneal dialysis.

Optimum dietary protein requirement in nondiabetic maintenance hemodialysis patients

Background: There is controversy about whether the dietary protein requirement of 1.2 g/kg/d for hemodialysis (HD) patients, in the nutritional guidelines recommended by the National Kidney Foundation-Kidney Disease Outcomes Quality Initiative (NKF-KDOQI), is reasonable. Methods: A cross-sectional study was conducted in 129 stable HD patients without diabetes (84 men, 45 women) to investigate the association between the protein equivalent of nitrogen appearance normalized by ideal body weight (nPNAibw), an index of protein intake, and skeletal muscle mass or other metabolic consequences. Patients were divided into 5 groups according to nPNAibw index. Midthigh muscle area (TMA), midthigh subcutaneous fat area (TSFA), abdominal muscle area (AMA), abdominal subcutaneous fat area (ASFA), and visceral fat area (AVFA) were measured using computed tomography, and various nutritional parameters were compared among these groups. Results: TMA and AMA values increased with increasing dietary protein intake from less than 0.7 g/kg/d to 0.9–1.1 g/kg/d and showed a plateau at greater than 0.9 to 1.1 g/kg/d of dietary protein intake. Conversely, fat mass, including TSFA, ASFA, and AVFA, and serum potassium concentration increased with graded protein intake, and no plateau was formed. Patients with nPNAibw greater than 1.3 g/kg/d satisfied the criterion of visceral obesity. Although serum prealbumin levels showed a trend similar to that of muscle mass, there was no significant difference in serum albumin levels among the study groups. Conclusion: Optimal dietary protein requirement for patients undergoing maintenance HD in a stable condition appears to be less than the level recommended by the NKF-KDOQI nutritional guidelines.

Adverse Prognostic Indicators in Continuous Ambulatory Peritoneal Dialysis Patients without Obvious Vascular or Nutritional Comorbidities

Factors that predict the occurrence of vascular events and poor patient survival in continuous ambulatory peritoneal dialysis (CAPD) patients have not been clearly defined. Previous studies have focused on nonselective CAPD patients, in whom pre-existing comorbidity or poor health might complicate interpretation of the significance of individual factors. The present study was conducted with CAPD patients without severe vascular and nutritional comorbidity. This single-center, prospective, observational study was conducted with 66 prevalent CAPD patients without co-existing severe vascular or nutritional problems. The patients were enrolled in January 1999. We monitored baseline demographic data and clinical and laboratory characteristics including average clinic blood pressure (BP), hemoglobin (Hb), serum albumin, intact parathyroid hormone (iPTH), serum cholesterol, triglycerides, dialysate-to-plasma (D/P) creatinine, dialysis adequacy [Kt/V and creatinine clearance (CCr)], and protein equivalent of nitrogen appearance. We followed the patients for 3 years. Outcome measures were actuarial patient survival, time to occurrence of cerebrovascular accident (CVA) and acute myocardial infarction (AMI), technique survival, and hospitalization rate. Mean age of the patients was 56.7 +/- 10.3 years. Mean duration on CAPD at the time of enrollment was 36.4 +/- 21.7 months. Nineteen of the patients (28.8%) had diabetes. Most of the patients [n = 55 (83.3%)] were using three 2-L exchanges daily. Mean body weight was 56.3 +/- 12.2 kg. Mean total weekly Kt/V was 1.91 +/- 0.47, and mean total weekly CCr was 75.3 +/- 30.6 L/1.73 m(2). Actuarial patient survival was 96.9% at 1 year, 90.5% at 2 years, and 75.3% at 3 years. Overall technique survival was 96.9% at 1 year, 95.1% at 2 years, and 89.1% at 3 years. Multivariate analysis showed that age, diabetes mellitus (DM), and body size (weight or surface area) were independent predictors of patient survival. We estimated that a 1-kg increase in body weight was associated with a 6% increase in the relative risk of death (p = 0.015; 95% confidence interval: 1.013 to 1.126). Patients with a body weight of 60 kg or less showed a significantly better 3-year survival as compared with patients with body weight greater than 60 kg (88.1% vs 58.3%, p = 0.0042). No significant predictors were identified for technique failure or occurrence of a major vascular event. High BP and DM were independent predictors for hospitalization. Dialysis adequacy indices and serum albumin showed no significant effect on any outcome measure. Our study showed that, in addition to age and DM, body size could also be a significant factor affecting survival of CAPD patients. However, the underlying causative mechanisms remain unclear and require further study.

Are Three Exchanges Suitable for Asian Patients on Peritoneal Dialysis?

Phenomenal growth in continuous ambulatory peritoneal dialysis (CAPD) has occurred in the developing countries of Asia. In many regions in Asia, neither governments nor insurance companies fully cover treatment expenses for dialysis. Hence, patients in developing countries such as India, Bangladesh, Pakistan, and Nepal use just three 2-L exchanges daily. Typical practice in many centers is to do daytime CAPD with a dry night. Most of our Indian patients who are on three exchanges per day showed a Kt/V of 1.67 and 2-year survival rate of 60% with a normalized protein equivalent of nitrogen appearance of 0.73 - 0.80 g/kg daily. Vegetarians had a lower protein consumption rate and lower serum albumin levels. Peritoneal membrane characteristics vary among high, high average, and low average in various regions of Asia. The prevalence of diabetic nephropathy, with its associated comorbid conditions, as a major cause of end-stage renal disease in the Indian subcontinent explains the differences in the CAPD mortality rates between India and various Asian countries. Given the financial constraints in countries in Asia, small-volume dialysis of 6 L daily may be an acceptable compromise in some patient populations with a smaller body size and significant residual renal function; however, dialysis dose should be individualized according to the needs of each patient.

Influence of renal function on spontaneous dietary intake and on nutritional status of chronic renal insufficiency patients.

To analyze the spontaneous food intake and the nutritional parameters of patients with different degrees of chronic renal insufficiency (CRI) at the onset of predialysis treatment. Cross-sectional. Outpatient Clinic of the Nephrology Division of Federal University of São Paulo, Brazil. The analysis involved 487 (187 women and 300 men) patients with moderate to advanced CRI who were evaluated in the first visit to the clinic. Patients were divided according to creatinine clearance (CrCl) quartiles. CrCl in the first quartile was lower than 19.9 ml/min/1.73 m(2) and in the fourth one was higher than 43 ml/min/1.73 m(2). Energy intake was significantly (P<0.05) lower in the first quartile when compared with the fourth one while protein intake estimated by protein equivalent of nitrogen appearance (PNA) was significantly lower in the first, second and third quartiles in comparison with the fourth (P<0.05). Body mass index (BMI) and percentage of ideal body weight were significantly decreased in the three lowest levels of renal function. Standard per cent of triceps skinfold thickness was lower in the first quartile when compared with the fourth one. Compared with the fourth quartile, standard per cent of midarm muscle circumference (MAMC) was lower in the second and in the third quartile. CrCl correlated directly and significantly with PNA (r=0.30; P<0.01), energy intake (r=0.17; P<0.01), and MAMC (r=0.20; P<0.01). In a multiple linear regression analysis, controlling for energy and protein intake, CrCl correlated significantly and positively with BMI and MAMC. This study suggests that a spontaneous decrease in energy and protein intake as well as in anthropometric indices follows a decline in renal function in patients with no previous dietary intervention.

A 3-year, prospective, randomized, controlled study on amino acid dialysate in patients on CAPD

Background:Malnutrition is prevalent in patients on continuous ambulatory peritoneal dialysis (CAPD) and confers a poor prognosis. Inadequate nutrient intake is an important contributing factor. Although short-term studies have shown mild to modest nutritional benefit with amino acid dialysate, its long-term effects and tolerability remain obscure. Methods:The authors have performed a 3-year, randomized, prospective, controlled study of amino acid dialysate in malnourished Chinese patients on CAPD. Sixty patients were assigned randomly to either replace 1 exchange daily with amino acid dialysate (Nutrineal; DAA group, n = 30) or to continue with dextrose dialysate (Dianeal; DD group, n = 30). Results:The 2 groups had similar mortality, hospitalization duration, serial C-reactive protein levels, and drop-out rates during the study. Biochemical nutritional parameters including albumin and cholesterol decreased in the DD group but remained stable or increased in the DAA group. The composite nutritional index did not differ between the 2 groups throughout the study period. Triglyceride decreased only in DAA-treated patients. Normalized protein equivalent of nitrogen appearance and dietary protein intake showed a sustained increase only in DAA patients. The nutritional benefit of DAA appeared more prominent in women, whose lean body mass and body mass index was maintained with DAA but not with DD. Mass transfer area coefficient for creatinine increased in DAA-treated patients, whereas that for urea as well as macromolecular restriction coefficients remained stable. Total Kt/Vurea and daily ultrafiltration volume were similarly maintained in the 2 groups throughout the study. Conclusion:Long-term administration of amino acid dialysate is well tolerated and presents a means to improve the nutritional status in high-risk patients. The current study, however, has not shown a significant effect of amino acid dialysate on patient survival.

Suitable Dialytic Indicators for Pediatric Peritoneal Dialysis Patients: The Alternative to Creatinine Clearance

Owing to the discord between body weight and body surface area (BSA), creatinine clearance (CCr) is predisposed to be small in pediatric patients on peritoneal dialysis (PD). Alternatively, Kt/V creatinine (Kt/V creat), which is normalized to total body water (TBW) rather than BSA, could be a better dialytic indicator. In this study, the efficiency of dialysis and the nutritional status of pediatric patients on chronic PD were examined, and the utility of dialytic indicators was evaluated. 49 patients under 20 years old, in stable condition, and on PD were analyzed. Weekly total Kt/V of urea (Kt/V urea), CCr, Kt/V creat, and normalized protein equivalent of nitrogen appearance (nPNA) were measured for all patients and for patients under 6 years old. The target value was 2.0/week for Kt/V urea and 60 L/ week/1.73 m2 for CCr, as recommended by the Kidney Disease Outcomes Quality Initiative guidelines. The target value for Kt/V creat was set as 1.52/week, using a male model with a height of 170 cm and a body weight of 65 kg. The mean values of delivered Kt/V urea, CCr, Kt/V creat, and nPNA (and proportion of patients that achieved each target value) for all patients were 2.25 +/- 0.57/ week (67.4%), 53.8 +/- 19.3 L/week1/.73 m2 (26.5%), 1.83 +/- 0.73/ week (65.3%), and 1.11 +/- 0.42 g/day, respectively. The values for patients under 6 years old were 2.38 +/- 0.26/week (90.0%), 45.9 +/- 12.8 L/week/1.73 m2 (10.0%), 1.94 +/- 0.51/week (90.0%), and 1.52 +/- 0.67 g/day, respectively. Stepwise multiple regression analyses revealed that the relationship between CCr and Kt/V urea was affected by the patient's age. Our pediatric patients achieved the recommended target value of Kt/V urea. At the same time, the nPNA results reflected the patient's status well. However, CCr appeared to be inappropriate as an indicator for patients under 6 years old. Kt/V creat is suggested to be a better dialytic indicator for these patients.

Randomized prospective comparison between erythropoietin and androgens in CAPD patients

Anemia and malnutrition are significant complications in peritoneal dialysis (PD) patients. Previous studies in hemodialysis have shown that androgens are effective as therapy for anemia; however, this has not been tested in a randomized prospective trial in PD patients. Furthermore, the anabolic properties of androgens may exert additional benefits on the nutritional status in this population. Twenty-seven stable male patients over 50 years who were under maintenance continuous ambulatory peritoneal dialysis (CAPD) therapy were randomized to receive recombinant human erythropoietin (rHuEPO; N = 14) or nandrolone decanoate (ND; 200 mg/week IM; N = 13) as therapy for anemia. The evolution of hematologic parameters and the impact on both nutritional anthropometric and biochemical variables were evaluated after six months of treatment. Hemoglobin and hematocrit experienced similar increases in both groups: from 8.5 +/- 0.9 g/dL and 25.8 +/- 2.7% to 11.7 +/- 0.6 g/dL and 34.7 +/- 1.6% (P < 0.001) in patients receiving rHuEPO, and from 8.9 +/- 0.8 and 27 +/- 2.2% to 11.8 +/- 0.4 g/dL and 35.1 +/- 1.5% (P < 0.001) in subjects treated with ND. At the end of the study, out of the diverse nutritional variables included in this investigation, only weight and body mass index significantly increased in the rHuEPO group. Conversely, both anthropometric [weight, body mass index, triceps skinfold, mid-arm circumference (MAC) and mid-arm muscle circumference (MAMC)] and biochemical parameters (serum total proteins, albumin, prealbumin and transferrin) were significantly increased in patients treated with ND. In this group, serum urea nitrogen, urea net excretion and protein equivalent of nitrogen appearance significantly decreased. These facts, together with an increase in serum creatinine and no changes in dietary intake during the study, suggest a rise in muscle mass related to an anabolic effect of nandrolone decanoate. Interestingly, serum levels of insulin-like growth factor type 1 (IGF-1) increased in patients on the androgen group compared to subjects treated with rHuEPO. Moreover, there was a positive and significant correlation between the rise in IGF-1 concentrations and the increase in hemoglobin, hematocrit, MAC and MAMC. Androgens therapy improved the anemia in elderly male CAPD patients in a similar manner to that observed with rHuEPO. Furthermore, compared with rHuEPO, androgen administration was associated with beneficial effects on nutritional status. The mechanism of action of androgens on hematologic and nutritional parameters might be mediated, at least in part, by IGF-1.

Clinical performance measures: The changing status of peritoneal dialysis

The Peritoneal Dialysis-Clinical Performance Measures Project (PD-CPM) characterizes peritoneal dialysis within the U.S. Current survey results are reported and compared to those of previous years. Prevalence data from random national samples of adult peritoneal dialysis (PD) patients participating in the United States End-Stage Renal Disease (ESRD) program have been collected annually since 1995. In 1995, 79% of the respondents used continuous ambulatory peritoneal dialysis (CAPD) rather than automated peritoneal dialysis (APD). The mean hematocrit (Hct) of PD patients was 32% and only 66% of individuals had a measurement of dialysis adequacy reported. The mean weekly Kt/Vurea (wKt/V) and weekly creatinine clearance (wCCr) reported for CAPD patients in 1995 were 1.9 and 67 L/1.73 m2/week, respectively. In 2000 the median age of PD patients was 55 years and 63% were white. The leading cause of ESRD was diabetes mellitus (34%) and 54% of adult PD patients performed some form of APD rather than CAPD. Age, sex, size, hematocrit, peritoneal permeability, dialysis adequacy, residual renal function and nutritional indices did not differ between APD and CAPD patients. The mean hemoglobin (Hb) for the 2000 PD-CPM population was 11.6 +/- 1.4 g/dL (mean +/- 1 SD) and 11% of patients had an average Hb below 10 g/dL. The average serum albumin was 3.5 +/- 0.5 g/dL by the bromcresol green method and 56% of subjects had an average serum albumin equal to or above 3.5 g/dL (or 3.2 g/dL by bromcresol purple). In 2000 85% of patients had a dialysis adequacy measurement reported and the mean calculated wKt/V and wCCr were 2.3 +/- 0.6 and 72.7 +/- 24.9 liters/1.73 m2/week for CAPD patients and 2.3 +/- 0.6 and 71.6 +/- 25.1 L/1.73 m2/week for APD patients. PD subjects had a mean body weight of 76 +/- 19 kg and body mass index (BMI) of 27.5 +/- 6.4 kg/m2. The protein equivalent of nitrogen appearance (nPNA) of these patients was 0.95 +/- 0.31 g/kg/day, their normalized creatinine appearance rate (nCAR) equaled 17 +/- 6.5 mg/kg/day, resulting in a percent lean body mass (%LBM) of 64 +/- 17% of actual body weight. Serum albumin correlated in a positive fashion with BMI, nPNA, nCAR and %LBM, but not with wCCr. The majority of indicator variables monitored by the PD-CPM have improved since 1995. PD patients have higher hemoglobins and a greater proportion of patients meet the criteria for adequate dialysis. Serum albumin values, however, remain marginal and unchanged over the five-year project. Furthermore, serum albumin values fail to correlate with the intensity of renal replacement therapy and are not strongly correlated with alternative estimates of nutritional status.

Nutritional Markers during Peritoneal Dialysis: Data from the 1998 Peritoneal Dialysis Core Indicators Study

This analysis explores the nutritional status of adult U.S. peritoneal dialysis (PD) patients. The Peritoneal Dialysis Core Indicators Study is a prospective cross-sectional prevalence survey describing the care provided to a random sample of adult U.S. PD patients. Prevalence data were collected from a national random sample of 1381 adult PD patients participating in the United States End Stage Renal Disease (ESRD) program. The median age of these patients was 55 years, 61% were Caucasian; the leading cause of ESRD was diabetes mellitus. Age, sex, size, peritoneal permeability, dialysis adequacy, and nutritional indices did not differ between patients on continuous ambulatory PD and patients on automated PD. The dialysis prescriptions employed achieved mean weekly Kt/V urea (wKt/V) and creatinine clearance (wCCr) values of 2.22 +/- 0.57 and 67.8 +/- 22.5 L/1.73 m2/week, respectively. The PD patients were large, with a mean body weight of 77 +/- 21 kg and body mass index (BMI) of 27 +/- 8.6 kg/m2. The mean serum albumin of these patients was 3.5 +/- 0.51 g/dL, and 43% of values fell below the National Kidney Foundation Dialysis Outcomes Quality Initiative's desired range. The PD patients had a normalized protein equivalent of nitrogen appearance (nPNA) of 1.0 +/- 0.57 g/kg/day, a normalized creatinine appearance rate (nCAR) of 17 +/- 7.3 mg/kg/day, and an estimated lean body mass (%LBM) of 62% +/- 18% of body weight. Serum albumin correlated positively with patient size, nCAR, and nPNA, but negatively with age, the presence of diabetes mellitus, female gender, erythropoietin dose, the creatinine dialysate-to-plasma ratio results of peritoneal equilibration testing, and the dialysis portion of the wCCr. The duration of ESRD experience correlated negatively with both serum albumin and patient size, although these relationships were complex. Peritoneal dialysis patients generally have marginal serum albumin levels, a finding incongruent with alternative measures of nutritional status, such as weight, BMI, and creatinine generation. Serum albumin is reduced in patients with high peritoneal permeability (i.e., rapid transporters) and, because these patients generally have higher than average wCCr values, serum albumin is inversely correlated with the dialysis component of the wCCr. The presumptive nutritional indicators (BMI, %LBM, nPNA, and serum albumin) provide disparate estimates, varying from 10% to 50% for the prevalence of nutritionally stressed PD patients.

Nutritional status over time in hemodialysis and peritoneal dialysis.

Malnutrition is a risk factor for mortality in the dialysis population. So far, prospective studies comparing the time course of nutritional status in new hemodialysis (HD) and peritoneal dialysis (PD) patients have not been published. The aims of this study were to compare the time course of nutritional status in patients who were starting HD or PD and to identify the baseline determinants of that time course. In this prospective multicenter cohort study, data were collected from 3 (baseline) to 24 mo after the start of dialysis. Repeated measures ANOVA was used to establish the time course of nutritional status. Differences were adjusted for baseline characteristics. A total of 250 consecutive new patients were included: 132 started on HD, and 118 started on PD. A univariate analysis demonstrated a decrease in serum albumin (SA) in patients who started on HD and an increase in patients who started on PD. Body fat increased in PD; LBM did not change. The protein equivalent of nitrogen appearance normalized to ideal weight decreased in PD after 1 yr. In a multivariate analysis, SA at 2 yr was 2.0 g/L (95% confidence interval [CI], 0.3 to 3.8) higher in patients who started on PD compared with patients who started on HD. The increase in body fat was 3.2 kg (95% CI, 1.6 to 4.9) higher in women who started on PD than in others. Patients who had diabetes gained 2.3 kg (95% CI, 0.6 to 4.1) more fat than patients who did not have diabetes. Kt/V(urea) did not affect the time course of nutritional status, but a higher Kt(urea) was associated with a higher SA at 24 mo. Nutritional status at the start of dialysis, gender, and diabetic status might be considered in making the choice for dialysis modality. Furthermore, providing a higher Kt(urea) may improve protein metabolism.

Urea and nitrogen excretion in pediatric peritoneal dialysis patients

Adequate nutrition is critical to the care of children with end-stage renal disease, and failure to reach the target dietary intake is associated with growth failure. Prospective studies of urea and nitrogen output in adults have led to the derivation of quantitative relationships, which allow assessment of dietary protein intake when only urea appearance is known. Such a clinically useful relationship has not been defined in children receiving chronic peritoneal dialysis (PD). We studied 18 pediatric PD patients (ages 0.8 to 14.3 years) on 132 occasions and determined norms of urea nitrogen appearance (UNA), total nitrogen appearance (TNA), and nonurea nitrogen appearance (NUNA). We stratified data on UNA, TNA, NUNA, nonprotein nitrogen appearance, and the protein equivalent of nitrogen appearance by age groups (0 to 5, 6 to 10, and 11 to 15 years of age) and demonstrated significant differences. In addition, dietary protein and energy intake were measured in the outpatient setting with food scales and dietitian interviews, and the results were stratified by age, presence of residual renal function, and recombinant human growth hormone (rhGH) therapy. UNA (3.05 +/- 1.38 g/day, 103 +/- 42 mg/kg/day) and TNA (4.67 +/- 1.86 g/day, 159 +/- 52 mg/kg/day) varied significantly between different age groups. NUNA in pediatric subjects (56 +/- 24 mg/kg/day) was significantly greater than previously published adult norms. A linear relationship was defined between UNA and TNA that was specific to pediatric PD patients [TNA (g/day) = 1.26(UNA) + 0.83]. When the relationship was scaled to body mass, the y intercept was significantly different in the youngest subjects [TNA = 1.03 (UNA) + 0.02 (weight in kg) + 0.56 (for subjects age 0 to 5) or 0.98 (for subjects age 11 to 15 or 6 to 10), r2 = 0.91]. Dietary protein intake was significantly greater in subjects receiving rhGH therapy, although nitrogen excretion was unchanged. Markers of protein metabolism in pediatric PD patients are age dependent and differ from adult values. An age-specific relationship between TNA and UNA is defined for pediatric subjects; it does not vary with rhGH or the presence of residual renal function.