Automated vs continuous ambulatory peritoneal dialysis: a systematic review of randomized controlled trials.

BACKGROUND: A systematic review of randomized controlled trials (RCTs) comparing continuous ambulatory peritoneal dialysis (CAPD) with all forms of automated peritoneal dialysis (APD) was performed to assess their comparative clinical effectiveness. METHODS: The Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE and CINAHL, were searched for relevant RCTs. Analysis was by a random effects model and results expressed as relative risk (RR) and weighted mean difference (WMD) with 95% confidence intervals (CI). RESULTS: Three trials (139 patients) were identified. APD when compared to CAPD was found to have significantly lower peritonitis rates (two trials, 107 patients, rate ratio 0.54, 95% CI 0.35-0.83) and hospitalization rates (one trial, 82 patients, rate ratio 0.60, 95% CI 0.39-0.93) but not exit-site infection rates (two trials, 107 patients, rate ratio 1.00, 95% CI 0.56-1.76). However no differences were detected between APD and CAPD in respect to risk of mortality (RR 1.49, 95% CI 0.51-4.37), peritonitis (RR 0.75, 95% CI 0.50-1.11), switching from the original peritoneal dialysis (PD) modality to a different dialysis modality including an alternative form of PD (RR 0.50, 95% CI 0.25-1.02), PD catheter removal (RR 0.64, 95% CI 0.27-1.48) and hospital admissions (RR 0.96, 95% CI 0.43-2.17). Patients on APD were found to have significantly more time for work, family and social activities. CONCLUSIONS: APD appears to be more beneficial than CAPD, in terms of reducing peritonitis rates and with respect to certain social issues that impact on patients' quality of life. Further, adequately powered trials are required to confirm the benefits for APD found in this review and detect differences with respect to other clinically important outcomes that may have been missed by the trials included in this review due to their small size and short follow-up periods.     

Chronic peritoneal dialysis in Turkish children: a multicenter study

Chronic peritoneal dialysis (CPD) has been utilized in the treatment of children since 1989 in Turkey. The aims of this study were to summarize our experience with CPD in children and to establish a pediatric registry data system in Turkey. Standard questionnaires were sent to all pediatric CPD centers. 514 patients treated between 1989 and 2002 in 12 pediatric centers were enrolled in the study. Reflux nephropathy was the most common (18.1%) cause of renal failure. Mean age at dialysis initiation was 10.1±4.6 years. Mean duration of dialysis was 24.1±20.5 months. Continuous ambulatory peritoneal dialysis (CAPD) was the first CPD modality for 476 (92.6%) patients, 142 of whom switched to automated peritoneal dialysis (APD) during follow-up. Currently, 47.3% of the patients are still on CPD, 15.4% were transplanted, 13.2% switched to hemodialysis, 16.7% died. The patient and technique survivals were 90% and 95% at one year and 70% and 69% at five years, respectively. The survival was significantly shorter in the youngest age group (0–24 months) compared to those in older age groups (p=0.000). We herein report the first results of the TUPEPD study providing information on demographic data and survival of pediatric CPD patients. As opposed to clear recommendations in favor of APD, there is a clear preponderance of CAPD in our pediatric CPD population. That vesicoureteral reflux (VUR) is still the leading cause of renal failure is a distressing finding. Remarkably lower survival rates and transplantation ratios are as striking and distressing as the high incidence of VUR among the causes of ESRD. We conclude that we must make a great effort to achieve better results and to change these undesirable events.     

Polydipsia: a feature of peritoneal dialysis.

BACKGROUND: Some dialysis patients fail to comply with their fluid restriction causing problems due to volume overload. These patients sometimes blame excessive thirst. There has been little work in this area and no work documenting polydipsia among peritoneal dialysis (PD) patients. METHODS: We measured motivation to drink and fluid consumption in 46 haemodialysis patients (HD), 39 PD patients and 42 healthy controls (HC) using a modified palmtop computer to collect visual analogue scores at hourly intervals. RESULTS: Mean thirst scores were markedly depressed on the dialysis day (day 1) for HD (P<0.0001). The profile for day 2 was similar to that of HC. PD generated consistently higher scores than HD day 1 and HC (P = 0.01 vs. HC and P<0.0001 vs HD day 1). Reported mean daily water consumption was similar for HD and PD with both significantly less than HC (P<0.001 for both). However, measured fluid losses were similar for PD and HC whilst HD were lower (P<0.001 for both) suggesting that the PD group may have underestimated their fluid intake. CONCLUSION: Our results indicate that HD causes a protracted period of reduced thirst but that the population's thirst perception is similar to HC on the interdialytic day despite a reduced fluid intake. In contrast, the PD group recorded high thirst scores throughout the day and were apparently less compliant with their fluid restriction. This is potentially important because the volume status of PD patients influences their survival.     

Reduced systemic advanced glycation end products in children receiving peritoneal dialysis with low glucose degradation product content.

BACKGROUND: Glucose degradation products (GDP) in peritoneal dialysis (PD) solutions are toxic to the peritoneal membrane and promote the formation of advanced glycation end products (AGE), which contribute to accelerated atherosclerosis and amyloidosis. Double chamber PD solutions have a markedly reduced GDP content. METHODS: We analysed GDP and AGE kinetics in 21 children (7 months to 18 years) on automated PD in a prospective multicentre trial with randomized administration of single chamber, high-GDP and double-chamber, low-GDP dialysis solution for 12 weeks each. Total AGE fluorescence, carboxymethyllysine (CML, ELISA) and 3-deoxyglucosone (3-DG, HPLC) were measured in plasma and PD effluent during a 4 h peritoneal equilibration test. Plasma AGE profiles were assessed by size selective gel permeation chromatography and compared with 23 healthy controls. RESULTS: Initial effluent 3-DG concentrations were 140+/-55 and 25+/-4 micromol/l with high- and low-GDP PD fluid, respectively and declined to 53+/-32 and 7+/-2 micromol/l within 4 h dwell time (P<0.001). The ex vivo AGE generating capacity was three times higher with the high-GDP solution and decreased significantly with dwell time. Plasma AGE levels were 1.8-7.4-fold above those of healthy controls; the elevation was most marked for the small molecular fraction (<2 kDa). Plasma AGE and CML levels were significantly higher after 12 weeks exposure to high-GDP solution (20991+/-4145 AU and 1505+/-617 ng/ml) than following treatment with low-GDP fluid (17518+/-4676 AU and 1151+/-438 ng/ml; both P<0.05). Four hour AGE clearance was higher with low-GDP solution (0.74+/-0.3 vs 0.44+/-0.15 ml/min*1.73 m2, P<0.01). CONCLUSION: GDP are rapidly absorbed from the peritoneal cavity. Administration of PD solutions with low-GDP content reduces plasma AGE levels and may thus improve the cardiovascular risk profile of dialysed children.     

Peritoneal dialysis with solutions low in glucose degradation products is associated with improved biocompatibility profile towards peritoneal mesothelial cells.

BACKGROUND: In vitro experiments point to a better biocompatibility profile of new pH-neutral peritoneal dialysis fluids (PDFs) containing low levels of glucose degradation products (GDPs). The present study examines the impact on human peritoneal mesothelial cells (HPMCs) of equilibrated dialysates obtained during dialysis with either conventional or new PDFs. METHODS: Peritoneal dialysate was collected from 17 patients participating in a randomized, controlled, cross-over trial comparing a pH-neutral low-GDP solution (Balance) to a conventional solution (S-PDF). All patients were treated sequentially for 3 months with both PDFs. At the end of each treatment phase, peritoneal effluent was drained after a timed 10 h dwell. Samples of dialysate were then mixed with standard culture medium and added to in vitro cultures of HPMCs from healthy donors. Cells were assessed for proliferation, viability and cytokine release. RESULTS: Proliferation and viability of HPMCs were better preserved in the presence of effluent obtained during dialysis with Balance (P<0.046 and P<0.035, respectively). The proliferative response of HPMCs correlated with the concentration of fibronectin in dialysates (P = 0.0024). Effluent drained following a 3 month dialysis with Balance contained significantly increased levels of fibronectin (P = 0.004) and CA125 antigen (P = 0.0004) compared with S-PDF. There was no significant difference in constitutive and stimulated cytokine (IL-6, MCP-1, VEGF) synthesis by HPMCs treated with either Balance- or S-PDF-derived effluents. CONCLUSIONS: These results suggest that therapy with new pH-neutral low-GDP solutions contribute to an intraperitoneal milieu that improves mesothelial cell proliferation and viability. It may positively impact on the preservation of the peritoneal membrane integrity during long-term dialysis.     

Use of pure bicarbonate-buffered peritoneal dialysis fluid reduces the incidence of CAPD peritonitis.

BACKGROUND: Advances in bag connection technology have reduced the incidence of peritonitis in CAPD patients but there is little information on the effect of the new peritoneal dialysis fluids. METHODS: We studied the incidence of CAPD peritonitis for about 3 years in 100 incident patients--50 patients dialysed with lactate-buffered solution, pH 5.5 and containing glucose degradation products (GDP) (lactate group), and 50 patients with pure bicarbonate-buffered solution, pH 7.4 and low GDP (bicarbonate group). Patients in both groups were similar in age, sex, length of time on CAPD, connection technology and handling of dialysis. RESULTS: In the lactate group, 74 episodes of peritonitis were recorded compared with 43 in the bicarbonate group, i.e. one episode per 21 patient-months with the lactate dialysis fluid and one episode per 36 patient-months with the bicarbonate dialysis fluid (OR 0.58, 95% CI 0.37-0.91, P = 0.017). A total of 3369 exchanges per episode of peritonitis were recorded for bicarbonate compared with 2004 exchanges per episode of peritonitis in the lactate group. The majority of organisms isolated in both groups were Gram-positive bacteria, with a predominance of the oropharyngeal and cutaneous endogenous flora. Three episodes of fungal peritonitis occurred in the lactate group and none in the bicarbonate group. CONCLUSIONS: Our results suggest that the pure bicarbonate-buffered peritoneal dialysis fluid appears to reduce the frequency of peritonitis in CAPD patients possibly in relation to greater biocompatibility and maintenance of peritoneal membrane structural integrity. Similar results can probably relate to all low-GDP solutions.     

Comparison of infectious complications in peritoneal dialysis patients using either a twin-bag system or automated peritoneal dialysis.

BACKGROUND: Automated peritoneal dialysis (APD) and twin-bag (TB) systems are two major peritoneal dialysis (PD) modalities. Published data comparing the infectious complications of these modalities is limited. Subjects and methods. Ninety-five patients using APD (the APD group) and 117 patients using TB system (the TB group) were recruited. Among them, 35 patients used both modalities. The two groups' clinical characteristics, incidences of infectious complications, and the time intervals to first PD-related infection were compared. RESULTS: Clinical characteristics, incidence of exit-site infection (ESI), and time intervals to first ESI were similar in the TB and APD groups. The incidence of peritonitis in the APD group (1.22 episodes/100 patient-months) was significantly (P < 0.001) lower than that of the TB group (2.28 episodes/100 patient-months). Using the Cox proportional hazard model, APD was found to have a lower risk of peritonitis relative to TB systems, with marginal significance (RR 0.58, P = 0.051). CONCLUSION: APD was found to have a lower peritonitis rate than the TB system. Since reducing the peritonitis rate helps to maintain technical survival during PD, from this viewpoint, APD may be preferred for patients undergoing PD, unless contraindicated.     

Multidirectional approach to study peritoneal dialysis fluid biocompatibility in a chronic peritoneal dialysis model in the rat.

BACKGROUND: Peritoneal dialysis causes the functional and morphological changes in the peritoneum that result from the bioincompatibility of dialysis solutions. We present a model of chronic peritoneal dialysis in the rat that can be used for testing the biocompatibility of dialysis fluids. Methods and Results. Long-term exposure of the peritoneum to dialysis solutions can be performed in rats with implanted peritoneal catheters. Sampling of the dialysate allows the evaluation of intraperitoneal inflammation by examining cell differential and dialysate cytokine levels. Peritoneal permeability can be evaluated at designed time intervals with the peritoneal equilibration test (PET). At the end of dialysis, peritoneal histology is studied with light and electron microscopy. CONCLUSIONS: Such a multidirectional approach is an effective way to test biocompatibility of dialysis solutions.     

Peritoneal mesothelial cell biology in peritoneal dialysis

SUMMARY: Progressive peritoneal membrane hyperpermeability, ultrafiltration failure, and peritoneal fibrosis have been observed in long-term peritoneal dialysis (PD) patients, and these alterations in peritoneal structure and function may be responsible for the poor technique survival in PD. While frequent and/or severe peritonitis can result in alterations of the peritoneum, continuous exposure of the peritoneum to PD solutions may also adversely affect peritoneal structure and function. Peritoneal mesothelial cells (PMC) are directly and continuously exposed to unphysiological components of PD solution. Low pH, lactate, hyperosmolality, and glucose degradation products (GDP) reduce PMC viability and proliferation. High glucose, GDP, and advanced glycation end products (AGE) upregulate vascular endothelial growth factor (VEGF), monocyte chemoattractant protein (MCP)-1, transforming growth factor (TGF)-β1, plasminogen activator inhibitor (PAI)-1, and extracellular matrix protein expression by PMC, and may thus lead to peritoneal hyperpermeability, ultrafiltration failure, and peritoneal fibrosis, as observed in long-term PD. Activation of diacylglycerol (DAG)-protein kinase C (PKC) and generation of reactive oxygen species (ROS) are important upstream signalling events in high glucose-induced PMC activation. Thus, strategies to inhibit high glucose-induced PKC activation and ROS generation and the use of new PD solutions with non-glucose osmotic agents, pH neutral solutions, or solutions containing low GDP may allow better preservation of the structural and functional integrity of the peritoneal membrane during long-term PD.     

Supplementation with high-dose trans-resveratrol improves ultrafiltration in peritoneal dialysis patients: a prospective,randomized, double-blind study

Background Ultrafiltration (UF) failure mostly contributes to technical failure in peritoneal dialysis (PD) patients, and one of its responsible factors is peritoneal angiogenesis. Resveratrol has been proposed to have an angiogenesis-ameliorating effect on tumor patients. We hypothesize trans-resveratrol has beneficial effects on angiogenesis-related markers in PD patients. Methods In this prospective, randomized, and double-blind trial, 72 patients were randomly assigned to 12-week treatment of low-dose or high-dose (150 or 450?mg/d) trans-resveratrol or a placebo. Visits were scheduled at 0, 4, 8, and 12 weeks after treatment. Clinical indices including 24-hour UF volume, UF rate, 24-hour urine volume, residual renal function, and dialysis adequacy (kt/v) were measured. Angiogenesis markers including vascular endothelial growth factor (VEGF), fetal liver kinase-1 (Flk-1), angiopoietin-2 (Ang-2), tyrosine kinase 2 (Tie-2), and thrombospondin-1 (Tsp-1) in peritoneal effluent were also assessed by enzyme-linked immunosorbent assay. Results Finally, 64 out of 72 patients were analyzed, 18 in the high-dose group, 22 in the low-dose group, and 24 in the placebo group. Over the 12-week period, patients in the high-dose group [mean change from baseline (95% CI): 171.4 (141.3-201.5) (mL), p?=?0.003 (Net UF); 11.3(10.5-12.1) (mL/h), p?=?0.02 (UF rate)] or the low-dose group [mean change from baseline (95% CI: 98.1 (49.5-146.7) (mL), p?=?0.007 (Net UF); 6.5 (4.4-8.6) (mL/h), p?=?0.04 (UF rate)] versus the placebo group had a significantly greater improvement in mean net UF volume and UF rate. The appearance rates of VEGF, Flk-1, and Ang-2 were more significantly reduced (appearance rates of Tie-2 and Tsp-1 increased) in the high-dose group versus the placebo group, but not in the low-dose group. Conclusion Supplementation with trans-resveratrol is beneficial to improve ultrafiltration in PD patients, and high-dose supplementation may improve ultrafiltration by ameliorating angiogenesis induced by conventional lactate-buffered PD solutions.     

Different effects of amino acid-based and glucose-based dialysate from peritoneal dialysis patients on mesothelial cell ultrastructure and function.

BACKGROUND: Peritoneal dialysis fluid (PDF) containing amino acids has been introduced recently aiming to improve the nutritional status of PD patients. Dextrose-based PDFs have been implicated in progressive functional and structural deterioration of the peritoneal membrane. Limited data are currently available regarding the effect of amino acid-based PDF on the function and ultrastructure of human peritoneal mesothelial cells (HPMCs), which play a critical role in peritoneal membrane pathophysiology. METHODS: We investigated the effects of two commercially available PDFs, which utilized dextrose (1.5% Dianeal) or amino acids (1.1% Nutrineal) as the osmotic agent, obtained from patients after a 4 h dwell, on HPMC proliferation (MTT assay and cell counting) and viability [lactate dehydrogenase (LDH)release], interleukin-6 (IL-6) secretion (commercial enzyme-linked immunosorbent assay) and ultrastructure (scanning and transmission electron microscopy). RESULTS: Exposure of HPMCs to 1.5% Dianeal reduced cell proliferation, total cellular protein synthesis, IL-6 secretion and cell attachment, but prolonged the cell doubling time on recovery, and increased LDH release (P<0.001, P<0.001, P<0.0001, P<0.0001, P<0.001 and P<0.001, respectively). The 1.1% Nutrineal reduced HPMC proliferation (P<0.001) and increased IL-6 secretion (P<0.0001), but did not affect cell attachment, LDH release, protein synthesis or cell doubling time. Ultrastructural studies of HPMCs exposed to Dianeal showed cell flattening, increased cell surface area, reduced microvilli, and intracellular organelles compatible with dysfunctional mitochondria. In contrast, the ultrastructural morphology of HPMCs was relatively preserved after incubation with Nutrineal. CONCLUSIONS: Our results showed that HPMC ultrastructure, viability and protein synthesis were better preserved with amino acid-based PDF, compared with conventional dextrose-based PDF. The significance of IL-6 induction by Nutrineal remains to be elucidated.     

Intraperitoneal hydrostatic pressure and flow characteristics of peritoneal catheters in automated peritoneal dialysis.

BACKGROUND: In automated peritoneal dialysis (APD) one of the most important factors that influence the efficiency of the treatment is the total volume of dialysate infused per session and the dwell time. This study is aimed at examining the relationships between i.p. pressure (IPP), dialysate flow characteristics, and different dialysate fill volumes in order to optimize APD. METHODS: We studied 20 patients who received APD, with the standard fill volume (2 l, A), or individualized fill volumes based on the patient's body surface area (2.5 l/BSA/1.73 m, B) or on body weight (40 ml/kg body weight, C). The patient's tolerance to a given fill volume was evaluated by measuring IPP, and catheter flow characteristics were evaluated by an automated machine. RESULTS: IPP increased with the increase of the infused volume of dialysate (P < 0.05) and tended towards a positive relationship with the patient's body mass index (BMI: A vs IPP: R = 0.39, P = 0.0019; B vs IPP: R = 0.66, P = 0.0012; C vs IPP R = 0.55, P = 0.009). We also found a relationship between fill volume, BMI and IPP: IPP = 1.0839 + 0.53 (beta) x BMI + 0.211 (beta) x fill volume (R = 0.65; r(2) = 0.40 P < 0.01). The mean IPP with different dialysate fill volumes tended to be related to the volume of dialysate drained at the transition point (R = 0.37; P < 0.05). The pre-transition flow rate/mean IPP ratio tended towards a positive relationship with the volume of dialysate drained at the transition point (R = 0.35, P < 0.05), the transition time (R = 0.34; P < 0.05) and a negative one with the transition volume (R = -0.35, P = 0.05). CONCLUSION: It is possible to customize APD, where the tidal percentage coincides with the transition point for a given catheter and a specific initial dialysate fill volume, the tolerance of which can be measured by assessing IPP.     

Aspergillus fumigatus peritonitis in ambulatory peritoneal dialysis: a case report and notes on the therapeutic approach

Aspergillus peritonitis is a rare disease in continuous peritoneal dialysis. It is a severe form of peritonitis, which is frequently lethal. We report a case of Aspergillus fumigatus peritonitis in a female patient on automated peritoneal dialysis (APD), who was successfully treated with intravenous amphotericin B and the removal of the peritoneal catheter. As delayed treatment has an increased mortality rate, it is mandatory to remove the catheter and to start intravenous treatment with amphotericin B empirically.     

A high peritoneal large pore fluid flux causes hypoalbuminaemia and is a risk factor for death in peritoneal dialysis patients.

BACKGROUND: Hypoalbuminaemia is common in peritoneal dialysis (PD) patients and has an associated high mortality. An excess morbidity and mortality has previously been found in patients with high peritoneal transport. A high peritoneal large pore fluid flux (Jv(L)) results in increased peritoneal loss of protein that possibly contributes to patient morbidity. Alternatively, hypoalbuminaemia and high transport status could be just a marker of capillary pathology associated with atherosclerotic comorbidity. METHODS: Peritoneal dialysis capacity computer modelling of peritoneal transport, based on Rippe's three-pore model, was performed to measure Jv(L) in 155 incident PD patients 2-4 weeks after PD initiation. Patient clinical and biochemical status was determined -6, -3, -1, 1 and 6 months after PD initiation, and every 6 months thereafter. Jv(L) was redetermined in prevalent patients 2 and 4 years after PD initiation. RESULTS: Jv(L) was 0.106+/-0.056 ml/min/1.73 m(2) (median 0.094, interquartile range 0.068-0.128). It was correlated to age*** (*P<0.05; **P<0.01; ***P<0.001) (20-30 years 0.079+/-0.04; 70 years 0.121+/-0.071), but not to gender. No correlation to diabetic or preexisting renal replacement therapy was seen, but patients with atherosclerosis had higher Jv(L) (0.123+/-0.06 vs 0.100+/-0.056*) as had patients with other systemic disease (0.121+/-0.68 vs 0.100+/-0.051*). Jv(L) was positively correlated to area parameter (r = 0.41***), and negatively correlated to plasma albumin (-0.36***). Patients were divided into three equal groups: group 1, Jv(L) <0.075 ml/min/1.73 m(2); group 2, 0.075-0.11; group 3: >0.11. There was no difference between the groups in p-albumin prior to PD. Immediately after PD start, differences between the three groups appeared (1 month p-albumin: (micromol/l) group 1, 548+/-83; group 2, 533+/-86; group 3, 497+/-78**), and persisted for up to 6 years. No significant change in Jv(L) was seen at 2 and 4 years. Patients with significant albuminuria also had hypoalbuminaemia (<1 g/day: 546+/-81 mumol/l; >2 g/day: 503+/-54 micromol/l). Intermittent PD ameliorated the effect of Jv(L) on albumin losses and clearance. Mortality was increased significantly with raised Jv(L), independently of age (2 year mortality: group 1, 10%, group 3, 32%*). There was no overall effect on technique survival, but hypoalbuminaemic group 3 patients had a higher failure rate. CONCLUSION: Jv(L) is related to hypoalbuminaemia and mortality after PD initiation. A high Jv(L) seems to be a marker of preexisting vascular pathology, and to cause hypoalbuminaemia after PD initiation. It is suggested that peritoneal albumin loss can have an identical pathogenic effect as urinary albumin loss, by causing an iatrogenic "nephrotic" syndrome.     

Individualized bicarbonate concentrations in the peritoneal dialysis fluid to optimize acid-base status in CAPD patients.

BACKGROUND: A large percentage of peritoneal dialysis (PD) patients being treated with standard lactate-containing solutions tend to have serum bicarbonate concentrations below or above the normal range. The inter-patient variability of serum bicarbonate is a result of many influences and it may be appropriate to adjust the bicarbonate concentration in the peritoneal dialysis fluid (PDF) to the current serum bicarbonate in the individual patient. METHODS: Two concentrations of bicarbonate in PDF were compared in this study (34 and 39 mmol/l). Eligible patients underwent a pre-study phase of 12 weeks to determine serum bicarbonate every six weeks. Sixty-one patients entered the stratification phase. Acidotic patients (serum venous bicarbonate <25.3 mmol/l) were allocated to the high bicarbonate solution, patients in the normal serum bicarbonate range or alkalotic patients (serum venous bicarbonate >25.3 mmol/l) to the low bicarbonate solution. Patients were followed up for 24 weeks, in which study visits were performed every 6 weeks to assess acid-base status, peritoneal and renal function, and to calculate protein nitrogen appearance rate (PNA). RESULTS: Patients with acidosis at baseline had higher body weight, body surface area, blood urea nitrogen, serum creatinine and PNA than patients with bicarbonate within the normal range or with alkalosis. They significantly improved their serum bicarbonate (23.45 +/- 2.5 vs 25.7 +/- 2.8 mmol/l, baseline vs week 24; P < 0.01), whereas patients treated with the low bicarbonate PDF maintained their serum venous bicarbonate over the 24 week study period (27.77 +/- 2.9 vs 27.06 +/- 2.1 mmol/l, baseline vs week 24; P = NS). Analysing both study groups together, at baseline, 66% of the patients presented with mild to moderate acidosis, this figure at the end of the study was 23.4%. PNA did not change in the two groups; however, in the subgroup of patients (N = 23) in whom the 39 mmol/l PDF was effective in correcting metabolic acidosis, a decrease in PNA was observed. CONCLUSIONS: The study demonstrated that the individualized application of low and high bicarbonate PD PDFs allows one to achieve normal acid-base status in a large percentage of CAPD patients with potential benefits to nutritional status.