Factors associated with increased plasma homocysteine in patients using an amino acid peritoneal dialysis fluid.

BACKGROUND: Although amino acid peritoneal dialysate (AAPD) substitution is thought to improve protein-energy malnutrition in patients undergoing peritoneal dialysis (PD), it may also increase plasma homocysteine (Hcy) levels due to the methionine load in the dialysate. However, it is still unclear which factors are important for elevating Hcy in patients treated with AAPD. METHODS: Sixteen malnourished PD patients (age 48+/-18 years) were treated daily with one exchange of 1.1% AAPD for 3 months. The effects of AAPD on nutrition, Hcy, methionine, leptin and insulin resistance were studied. We also analysed factors that influenced plasma Hcy levels. RESULTS: We found a transient increase in serum albumin (P<0.01) after 1 month treatment, especially in patients with serum albumin < or = 3.5 g/dl. Total plasma Hcy increased markedly after AAPD (the peak at month 2, P<0.001) and returned to baseline after ceasing AAPD, despite no changes in dietary methionine intake and serum methionine levels. Eight patients with Hcy increments >5.65 microM (the median) had lesser dietary intakes of protein (P = 0.01) and methionine (P = 0.028), lower body fat mass (P = 0.05) and lower aspartate transaminase (AST) (P = 0.008) before AAPD treatment than patients with lower increments. DeltaHcy was inversely correlated with baseline dietary methionine intake (r = -0.61), protein intake (r = -0.54) and AST (r = -0.51) (all P<0.05). There was no change in leptin or insulin resistance. AAPD treatment significantly increased Kt/Vurea (P<0.001), weekly creatinine clearance (P<0.05) and peritoneal glucose transport (P<0.05). CONCLUSIONS: Treatment with 1.1% AAPD transiently increased serum albumin in malnourished PD patients. However, the methionine load from the dialysate in this study significantly elevated plasma Hcy levels, especially in patients with lower protein and methionine intakes, and lower AST levels. Further long-term studies will be needed to clarify potential nutritional benefits and adverse effects of AAPD.     

Influence of haemodialysis on plasma total homocysteine concentration.

BACKGROUND: The high prevalence of hyperhomocysteinaemia in uraemic patients is of interest because of the cardiovascular risk associated with increased plasma total homocysteine (tHcy) concentration. Treatment with folic acid lowers tHcy in haemodialysis patients, however, in most patients not to normohomocysteinaemic levels. With possible tHcy-lowering modifications in mind, we studied the influence of standard haemodialysis on tHcy. METHODS: In 56 folate-loaded haemodialysis patients, tHcy and parameters of dialysis adequacy were measured. In six patients, interdialytic curves of tHcy and serum creatinine concentrations were obtained and in five patients, the amount of homocysteine (Hcy) in dialysate was determined. RESULTS: tHcy (21.8+/-14.4 micromol/l) correlated significantly with Kt/V (r=0.32, P<0.05), total Kt/V (r=0.29, P<0.05), nPCR (r=0.30, P<0.05) and serum concentrations of albumin (r=0.28, P<0.05) and cobalamines (r=-0.27, P<0.05). In a multiple linear regression analysis, only serum albumin concentrations significantly predicted tHcy (r=0.34, P < 0.05). During dialysis, tHcy decreased by 28% and remained constant for at least 8 h after treatment. The amount of Hcy recovered in dialysate was 63 micromol (12-158 micromol). There was no difference in tHcy between those who had residual renal function and those who had not. CONCLUSIONS: The direct relationship between tHcy and Kt/V seemed to be mediated by the serum albumin concentration. The shape of the interdialytic tHcy curve suggested facilitated Hcy removal for at least 8 h after dialysis possibly due to reduced levels of inhibitory activities against relevant enzyme(s). The dialysed amount of Hcy did not seem to contribute significantly to Hcy removal. Thus, modifications of standard dialytic regimens are not likely to be effective from a tHcy-lowering point of view whereas convective procedures such as haemofiltration or haemodiafiltration might be more effective.     

Determinants of haemoglobin carbamylation in haemodialysis and peritoneal dialysis patients.

BACKGROUND: Carbamylation is an irreversible process of non-enzymatic modification of proteins by the breakdown products of urea. For haemoglobin (Hb), the extent of carbamylation is a marker of urea exposure and has been proposed as an indicator of the control of uraemia by dialysis, analogous to the use of Hb glycosylation in diabetic patients. METHODS: We performed a cross-sectional study of haemodialysis (HD) and peritoneal dialysis (PD) patients in order to study potential determinants of carbamylated Hb (CarbHb) and to investigate the relationship between CarbHb and established measures of dialysis dose/adequacy by multivariate analysis. RESULTS: In 80 HD patients, CarbHb was independently predicted by post-dialysis urea (r=0.40, P:<0.01), serum albumin (r=0.24, P:<0.05) and serum bicarbonate (r=-0.40, P:<0. 05). No correlation was found between CarbHb and measures of dialysis dose/adequacy (Kt/V, urea reduction ratio, weekly dialysis duration, and normalized protein catabolic rate (nPCR)). In 42 PD patients, serum urea was the only significant independent predictor of CarbHb (r=-0.51, P:=0.001). No relationship was found between CarbHb and Kt/V, corrected creatinine clearance (CrCl) or nPCR in PD patients. CONCLUSIONS: Serum urea is the most consistent independent predictor of CarbHb in dialysis patients. This association in combination with the lack of a relationship with conventional measures of dialysis dose and a positive relationship with serum albumin suggest that a single measurement of CarbHb is unlikely to be a useful indicator of the adequacy of dialysis.     

Peritoneal dialysis adequacy and risk of death

BACKGROUND: The purpose of this study was to evaluate the relationship between dialysis dose, patient characteristics, and medical comorbidities on mortality in chronic peritoneal dialysis patients. METHODS: This work comprised a study cohort of 1446 patients obtained from a random sample of chronic peritoneal dialysis patients from each dialysis center in three southeastern states. Data collected on a standardized form were used to calculate weekly Kt/V urea and creatinine clearance. Data were linked to Network files containing data on patient demographic and medical comorbidities. RESULTS: Both weekly Kt/V urea and creatinine clearance were measured at least once in only 60.5% of continuous ambulatory peritoneal dialysis (CAPD) patients and 63.7% of cycler patients. Among the 873 patients who had at least one calculable adequacy measure, the mean (+/-SD) weekly Kt/V urea was 2.13 +/- 0.55, and the normalized mean weekly creatinine clearance was 62.9 +/- 20.4 L/week/m2. During the seven month period of follow-up, there were 140 deaths. In separate logistic regression models that included all of the studied risk factors, using separate variables for the urinary and peritoneal components of dialysis adequacy, each 10 L/week/1.73 m2 increase in the urinary component of weekly creatinine clearance was associated with a 40% decreased risk of death, and each 0.1 unit increase in the urinary component of weekly Kt/V urea was associated with a 12% decreased risk of death. In contrast, the dialysate components of neither weekly creatinine clearance nor weekly Kt/V urea were predictive of death. Other factors that were associated with an increased risk of death included increasing age, diabetes mellitus as the cause of end-stage renal disease (ESRD), and a history of myocardial infarction. CONCLUSIONS: Residual renal function, as expressed by weekly creatinine clearance or Kt/V urea, is an important predictor of death in chronic peritoneal dialysis patients. The nonsignificant findings regarding peritoneal clearances and mortality may possibly be secondary to the narrow range of peritoneal clearances in this study cohort.     

The outcome for pediatric patients on peritoneal dialysis

BACKGROUND: The adverse effects of peritonitis and of the duration of dialysis on dialysis adequacy and clinical outcome were evaluated in this study. METHODS: The study comprised 24 chronic peritoneal dialysis patients who were followed up at least for 12 months. Casual blood pressure (BP) measurements, echocardiographic evaluation, peritonitis rate, hemoglobin (Hb), serum albumin, normalized protein catabolic rate (nPCR), total Kt/Vurea, weekly creatinine clearance (CCr), residual renal function (RRF), removal of fluid and dose of recombinant human erythropoietin (EPO) were evaluated. RESULTS: Mean age of the patients was 15.3 +/- 3.6 years. Mean follow-up was 50.4 +/- 26.8 months. Peritonitis rate was calculated as 1 episode/32.7 patient-months. Systolic hypertension was detected in 14 patients (58%) and diastolic hypertension in 15 (63%). RRF showed a negative correlation with duration on dialysis (r=-0.623, p=0.006).There was no significant correlation between RRF and nPCR, Hb, hematocrit, albumin and dose of EPO. A negative correlation was found with left ventricular mass index and fluid removal (r=-0.461, p=0.041). Higher doses of Kt/Vurea are associated with higher protein intake (r=0.503, p=0.024). A positive correlation was found between Kt/Vurea and Hb and Hct levels (r=0.460, p=0.009, and r=0.528, p=0.017, respectively). Dialysis adequacy tests were found not to be affected by the frequency of peritonitis. CONCLUSION: The most important factor for the prevention of hypervolemia in chronic peritoneal dialysis patients is RRF. The concept of adequate dialysis should include normal volume homeostasis, control of blood pressure and adequate nutrition.     

Is peritoneal dialysis adequate for hypercatabolic acute renal failure in developing countries?

BACKGROUND: Peritoneal dialysis (PD) is a therapeutic option for acute renal failure (ARF) in developing countries, despite concerns about inadequacy. Shorter and more efficient tidal peritoneal dialysis (TPD) was compared with continuous equilibrating peritoneal dialysis (CEPD) therapy in ARF by using their adequacies as accepted standards and analyzing the solute reduction indices (SRI). METHODS: A prospective, randomized crossover trial was performed in patients with mild to moderate hypercatabolic ARF who were assigned to CEPD and TPD therapy after an adequate washout period. Solute clearances (Kt/V, normalized creatinine clearances) were compared to NKF guidelines. Potassium and phosphate clearances, dextrose absorption, protein losses and costs were compared. Kt/V was compared to SRIdialysate, SRIKt/V. RESULTS: Eighty-seven patients with ARF received 236 sessions of dialysis (118 in each treatment). TPD resulted in higher clearances of solutes than CEPD (creatinine and urea clearances in mL/min of 9.94 +/- 2.93, 6.74 +/- 1.63 and 19.85 +/- 1.95, 10.63+/- 2.62, respectively, P=0.001). TPD and CEPD normalized creatinine clearances (L/week/1.73 m2 BSA) and Kt/V values were 68.5 +/- 4.43, 58.85 +/- 2.57 and 2.43 +/- 0.87, 1.80 +/- 0.32, respectively. CEPD did not meet standards of adequacy. TPD resulted in greater potassium and phosphate clearances, less dextrose absorption and was less expensive. CEPD resulted in less protein loss. Kt/V corresponded to SRIdialysate 0.88 +/- 0.12 (P=0.076). CONCLUSION: TPD produced higher solute clearances in less time with greater protein loss. CEPD just fell short to meet the dialysis adequacy standard. However, both TPD and CEPD are reasonable options for mild-moderate hypercatabolic ARF. Kt/V appropriately estimates solute removal in PD.     

Long-term use of 1.1% amino acid dialysis solution in hypoalbuminemic continuous ambulatory peritoneal dialysis patients

INTRODUCTION: Malnutrition is a common problem in patients treated with continuous ambulatory peritoneal dialysis (CAPD). Hypoalbuminemia in CAPD patients is an independent risk factor for death and is associated with malnutrition. Previous short-term studies have examined the use of amino acid based PD solutions in terms of albumin levels and anthropometric changes, but not clinical outcome. We report on the extended use of 1.1% amino acid based peritoneal dialysis solution (Nutrineal) and have assessed clinical utility in terms of nutrition, biochemical indices, dialysis adequacy and clinical outcomes. METHODS: The effect of Nutrineal was studied retrospectively in 22 patients during the past 30 months. All patients had an albumin level of < 35 g/l prior to commencing Nutrineal, and had either a protein intake < 1.2 g/kg or weight loss of > 5% in the previous 3 months. 19 of the 22 patients underwent an 8-week trial of oral nutritional supplements with no improvement in serum albumin level. Albumin level, normalized protein catabolic rate, weight, Kt/V and creatinine clearance were assessed for all patients prior to Nutrineal and at the end of the study period. RESULTS: The mean time on Nutrineal therapy was 13.6 months (range 6-26 months). There were no reported side effects of the treatment. There was an average of 1 episode of peritonitis per 23 treatment months, and only 1 patient died (4% annually adjusted mortality cf 8.9% on the peritoneal dialysis program as a whole). There was a significant increase in albumin level from 22.45 +/- 0.97 range 14-33 g/l to 25.68 +/- 1.159 range 16-35 g/l (p = 0.0036). Normalized protein catabolic rate increased significantly, from 0.898 +/- 0.053 to 1.085 +/- 0.056 g/kg/day (p = 0.0057). Weight decreased slightly although this did not reach statistical significance. Kt/V and creatinine clearance both decreased significantly, but remained within the adequate range in > 80% of the patients. There was no significant change in residual renal function (mean residual creatinine clearance 3.8 +/- 0.59 ml/min at the start of the study period, cf 3.4 +/- 0.61 ml/min at the end). CONCLUSION: These data suggest that Nutrineal can be used safely and effectively for an extended period of time. Such use is associated with a low mortality rate and a low peritonitis rate, although dialysis adequacy is compromised to a degree.     

Urea kinetics and other dialysis indices in children undergoing ambulatory peritoneal dialysis

Background. Peritoneal dialysis (PD) is an established treatment for children with end-stage renal failure. Creatinine clearance and urea kinetics are used to quantitate the dialysis treatment, but the means to assess the adequacy of dialysis in children are still controversial. Methods. We studied serum chemistry, dietary protein intake (DPI), protein catabolic rate (PCR), weekly urea clearance/body water (Kt/V_urea), weekly creatinine clearance (Ccr/week), clinical signs and symptoms during PD treatment, and peritoneal transport function in 17 children (4 to 18 years of age) with end-stage renal disease treated with PD. Fourteen children were on continuous ambulatory peritoneal dialysis (CAPD) and 3 were on automated peritoneal dialysis. Results. The mean values of the parameters tested were: blood urea nitrogen, 71 mg/dl; creatinine, 9.8 mg/dl; total protein, 6.4 g/dl; albumin, 4.0 g/dl; total Ccr, 70 l/week per 1.73 m²; DPI, 1.76 g/kg per day; PCR, 1.17 g/kg per day, and total Kt/V_urea, 2.28/week. The mean patient's clinical assessment score was 11.7, out of 15 and the mean doctor's clinical assessment score was 11.7, out of 14. The correlation between Kt/V_urea and creatinine clearance was 0.84 (P < 0.0001). Kt/V_urea and clinical assessment scores (patient's and doctor's scores) did not show a good correlation (r = 0.32; P = 0.228, and r = 0.47; P = 0.064, respectively). Peritoneal function seemed to be preserved after an average duration of 32 months on PD. Conclusions. These patients appeared to be fairly well dialyzed, judging from the values for the various dialysis indices obtained in this study and comparing them with adult indices. Received: January 7, 1999 / Accepted: March 22, 2000     

Nocturnal ultrafiltration profiles in patients on APD: impact on fluid and solute transport

In order to prevent morbidity and mortality in peritoneal dialysis (PD), sodium and water balance as well as a minimal level of small-solute clearances are needed. The impact of three nocturnal peritoneal ultrafiltration (UF) profiles on UF and small solute clearance in patients on automated PD (APD) was studied: constant glucose concentration of 1.36% (flat) or modifying the glucose concentration of the heater bag (descendant: 3.86-1.36%; ascendant: 1.36-3.86%). Sixty-two patients were enrolled in the study and received each profile within a four-month period, thus serving as their own controls. UF was lower with the flat profile (367+/-420ml; P<0.01), but no difference was seen between the two higher glucose concentration profiles. Peritoneal Kt/V (pKt/V) and peritoneal creatinine clearance (CrpC) showed statistically higher values from the descendant vs ascendant vs flat profiles (pKt/V: 1.54+/-0.30 vs 1.45+/-0.30 vs 1.38+/-0.27, and CrpC: 36.9+/-7.9 vs 33.5+/-7.48 vs 29.92+/-7.5 mlmin(-1)). Multivariate analysis showed statistical significance for the following: in the intrasubject comparisons, the profile for pKt/V (F=9.109, P<0.001) and CrpC (F=11.697, P<0.001), and in the intersubjects comparisons, the effects of both gender (F=14.334, P<0.01) for pKt/V and peritoneal permeability for both parameters (pKt/V: F=4.37, P<0.05; CrpC: F=11.697, P<0.001). In conclusion, the application of ascendant and descendant UF profiles in automated PD is feasible and results in better UF and small solute clearances, thus preventing inadequate dialysis and volume overload..     

Past, present, and future of quantified peritoneal dialysis

The role of peritoneal dialysis (PD) as a modality in renal replacement therapy has been well established. In this article we review various aspects in the evolution of PD, with special emphasis on adequacy. Until the late 1950s PD was still considered as a last resort in the treatment of terminal uremia. The introduction of a chronic indwelling catheter made chronic PD possible. The concept of continuous ambulatory peritoneal dialysis (CAPD), proposed in 1975, had a major impact on the way PD was performed later. The value of determining the adequacy, using urea clearance normalized to total body water (Kt/V) or creatinine clearance normalized to body surface area, was clearly highlighted by the Canada-USA (CANUSA) study. Introduction of standardized peritoneal equilibration tests has been very helpful in enhancing the efficiency of PD. In 1995 the National Kidney Foundation-Dialysis Outcomes Quality Initiatives (NKF-DOQI) established guidelines to improve patient survival and outcome on dialysis. These guidelines established minimum criteria for PD adequacy. Compliance and malnutrition remain important factors determining the efficacy of PD. The "healthy start" concept emphasizes an early start of dialysis in patients with end-stage renal disease (ESRD). The quest for an ideal PD modality has recently led to renewed interest in the idea of continuous flow peritoneal dialysis (CFPD). PD continues to grow and at the same time faces many challenges. Its role as a renal replacement therapy is likely to evolve further in the years to come.     

Serum creatinine can predict adequacy of peritoneal dialysis--preliminary report

AIM: To determine the value of creatinine clearance, estimated using the Cockcroft and Gault formula, in assessing adequacy of peritoneal dialysis. METHODS: We undertook a retrospective analysis of creatinine clearance results derived from a conventional 24-hour collection in 35 stable outpatients on peritoneal dialysis and compared them with those calculated from the corresponding serum creatinine using the Cockcroft and Gault formula. RESULTS: There was a strong correlation between the 2 methods (r = 0.82, p < 0.0001), although the formula tended to over-estimate clearances. The formula had a positive predictive value of 88% and a negative predictive value of 86% for detecting inadequate dialysis. CONCLUSION: The creatinine clearance calculated using the Cockcroft and Gault formula can be used in patients on peritoneal dialysis to estimate adequacy of dialysis. We believe that this method, which is far less expensive and time-consuming, deserves further testing in a larger population in order to define more accurately its role in the management of PD patients.     

Impact of dialysis adequacy on the mortality and morbidity of anuric Chinese patients receiving continuous ambulatory peritoneal dialysis

Dialysis adequacy has a major impact on the outcome of continuous ambulatory peritoneal dialysis (CAPD) patients. However, most studies on peritoneal dialysis adequacy have focused on patients with significant residual renal function. The present study examined the effect of dialysis adequacy on anuric CAPD patients. A single-center prospective observational study on 140 anuric CAPD patients was performed. These patients were followed for 22.0 +/- 11.9 mo. Dialysis adequacy and nutritional indices, including Kt/V, creatinine clearance (CCr), protein equivalent nitrogen appearance, percentage of lean body mass, and serum albumin level were monitored. Clinical outcomes included actuarial patient survival, technique survival, and duration of hospitalization. In the study population, 64 were male, 36 (25.7%) were diabetic, and 59 (42.1%) were treated with 6 L exchanges per day. The body weight was 59.2 +/- 10.2 kg. Average Kt/V was 1.72 +/- 0.31, and CCr was 43.7 +/- 11.5 L/wk per 1.73m(2). Two-yr patient survival was 68.8%, and technique survival was 61.4%. Multivariate analysis showed that DM, duration of dialysis before enrollment, serum albumin, and index of dialysis adequacy (Kt/V or CCr) were independent factors of both patient survival and technique survival. It was estimated that for two patients who differed only in weekly Kt/V, a 0.1 higher value was associated with a 6% decrease in the RR of death (P: < 0.05; 95% confidence interval, 0.92 to 0.99). Serum albumin and CCr were the only independent factors that predicted hospitalization. It was found that even when there is no residual renal function, higher dialysis dosage is associated with better actuarial patient survival, better technique survival, and shorter hospitalization. Dialysis adequacy has a significant impact on the clinical outcome of CAPD patients, and the beneficial effect is preserved in anuric patients as well as in an ethnic group that has a low overall mortality.     

Clinical outcome of continuous ambulatory peritoneal dialysis predicted by urea and creatinine kinetics.

The effectiveness of urea kinetics (Kt/V, where K is urea clearance, t is treatment time, and V is the volume of distribution for urea) to assess the adequacy of continuous ambulatory peritoneal dialysis (CAPD) and clinical outcome has not been established prospectively, and cross-sectional clinical studies have been inconclusive. A minimum weekly creatinine clearance of 40 to 50 L is recommended, but the adequacy of this dose is unproven. We introduced a simpler approach to creatinine kinetics in the form of an efficacy number (EN) calculated from data obtained in a standardized 4-h dwell exchange. To determine the most effective model for predicting CAPD adequacy, residual renal function, weekly Kt/V urea, weekly creatinine clearance standardized to body surface area, and EN (liters per gram of creatinine per day) were measured in 18 stable CAPD patients followed prospectively for at least 12 months. Patients were divided into three groups, good (G), intermediate (I), and poor (P), on the basis of uremic symptoms, mortality, hospital days, biochemical indices, and the need for transfer to hemodialysis. When comparing groups G (N = 6) and P (N = 8), weekly Kt/V were 2.3 +/- 0.2 versus 1.5 +/- 0.1 (P less than 0.005), weekly creatinine clearances were 71.5 +/- 8.6 versus 35.1 +/- 1.3 L (P less than 0.001), and EN were 7.4 +/- 0.8 versus 3.6 +/- 0.2 L/g of creatinine/day (P less than 0.005). Creatinine kinetics (weekly clearance and EN) but not urea kinetics could differentiate group I (N = 4) from groups G or P. Both urea and creatinine kinetics predict clinical outcome in CAPD.(ABSTRACT TRUNCATED AT 250 WORDS)     

Importance of dialysis adequacy in mortality and morbidity of chinese CAPD patients

BACKGROUND: In continuous ambulatory peritoneal dialysis (CAPD), the impact of dialysis adequacy on patient outcome is well established in Caucasian patients but is less clear in Asian patients. Recent evidence suggests that Asian dialysis patients enjoy better overall survival. We hypothesize that dialysis adequacy may be less important in determining outcome for this ethnic group. METHODS: We performed a single-center prospective observational study. From September 1995, we enrolled 150 existing and 120 new CAPD patients. They were followed for up to three years. We monitored dialysis adequacy and nutritional indices, including Kt/V, weekly creatinine clearance (CCr), residual glomerular filtration rate (GFR), normalized protein catabolic rate (NPCR), percentage of lean body mass (%LBM), and plasma albumin level. Clinical outcomes included mortality, technique failure, and duration of hospitalization. RESULTS: The duration of study follow-up was 22.1 +/- 12.3 months. In our study population, 136 were male. Seventy were diabetic (25.9%), and 212 were treated with 6 L exchanges per day (78.5%). The body weight was 59.3 +/- 9.4 kg. Baseline total Kt/V was 1.78 +/- 0.41, peritoneal Kt/V 1.48 +/- 0.36, and median residual GFR 0.98 mL/min (range 0 to 7.45). Two-year patient survival was 83.0%, and technique survival was 72.8%. Multivariate analysis showed that the duration of dialysis, diabetes, %LBM, index of dialysis adequacy (Kt/V or CCr), residual GFR, and requirement of a helper for CAPD exchanges were independent factors of patient survival; serum albumin, adequacy index (Kt/V or CCr), and requirement of a helper were independent factors of technique survival. Duration of dialysis, body weight, requirement of helper, cardiovascular disease, HBsAg carrier, serum albumin, and CCr had independent effects on hospitalization. The peritoneal component of Kt/V or CCr had no independent effect on any outcome parameter. When the prevalent and new CAPD cases were analyzed separately, Kt/V predicted survival only for new CAPD cases. CONCLUSIONS: Our results show that dialysis adequacy has significant impact on outcome of Asian CAPD patients. Although we have excellent medium-term patient and technique survival, this favorable outcome should not prevent health care workers from providing adequate dialysis to Asian patients. The reason of discrepancy in outcome between Asian and Caucasian dialysis patients requires further study.     

Clinical performance measures: the changing status of peritoneal dialysis.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.