The influence of automated peritoneal dialysis on the decrease in residual renal function

Correlation of Serum Albumin Levels With Laboratory Parameters in Automated Peritoneal Dialysis and Continuous Ambulatory Peritoneal Dialysis Patients: A Prospective Cohort Study

Background Peritoneal dialysis (PD) is a treatment option for end-stage renal disease (ESRD) patients, with automated peritoneal dialysis (APD) and continuous ambulatory peritoneal dialysis (CAPD) being the two main modalities. APD has reported benefits such as reduced peritonitis rates, improved ultrafiltration, and enhanced quality of life. However, some studies have found potential negative consequences of APD, and the impact on survival outcomes is limited and contradictory. Selecting the appropriate PD modality for ESRD patients should be individualized based on various factors, including nutritional status, demographic factors, laboratory findings, and other outcomes. PD patients are at high risk of malnutrition, and serum albumin is commonly used as a marker of nutritional status. Continuous monitoring of laboratory values may be beneficial for identifying nutritional deficiencies in a timely manner. Methodology This prospective cohort study aimed to compare APD and CAPD modalities in relation to serum albumin levels, demographic factors, and other laboratory parameters. The sample consisted of patients with ESRD treated with PD, who were divided into two groups per baseline albumin level. The study collected data on demographic, clinical, and laboratory characteristics, as well as comorbidities. The data were analyzed using SPSS version 26 (IBM Corp., Armonk, NY, USA), and statistical tests, such as the chi-square test and repeated-measures analysis of variance (ANOVA), were conducted to determine significant associations and differences between variables. Results The study included a total of 85 patients with ESRD who required PD as a treatment modality. Among them, 71 patients were undergoing APD, and 14 patients were undergoing CAPD. The study found that there were no significant differences in demographic factors, laboratory parameters, or medical history parameters between APD and CAPD patients with different albumin levels. The patients were followed up for six months and laboratory parameters were evaluated. Repeated-measures ANOVA showed that there were no significant variations in both APD and CAPD patients. However, Spearman's rank correlation test revealed statistically important correlations between albumin and some laboratory parameters in both APD and CAPD patients at different assessment stages, including hemoglobin, sodium, transferrin, uric acid, phosphate, total protein, cholesterol, and triglycerides (p < 0.05). Conclusions Serum albumin levels appeared to be unaffected by the choice of PD modality. There were significant correlations between serum albumin levels and specific laboratory findings, including total protein, across all assessment stages for both APD and CAPD patients. These findings underscore the importance of continuous laboratory monitoring for PD patients.

Astragalus Total Saponins Ameliorate Peritoneal Fibrosis by Promoting Mitochondrial Synthesis and Inhibiting Apoptosis

Peritoneal fibrosis (PF) is a disease caused by prolonged exposure of the peritoneum to high levels of dialysis fluid. Astragalus total saponins (ATS) is a phytochemical naturally occurring in Radix Astragali that has anti-inflammatory and anti-oxidant properties. In this study, we constructed an in vivo model of PF using 4.25% glucose-containing administered intraperitoneally to rats and incubated peritoneal mesothelial cells (PMCs) with 4.25% glucose-containing peritoneal dialysis fluid to construct an in vitro model of PF. Furthermore, siRNA of PGC-1[Formula: see text] was used to inhibit the expression of PGC-1[Formula: see text] to further investigate the mechanism of the protective effect of ATS on PF. In both in vivo and in vitro models, ATS treatment showed a protective effect against PF, with ATS reducing the thickness of peritoneal tissues in PF rats, increasing the viability of PMCs, increasing the mitochondrial membrane potential and reducing apoptosis ratio. ATS treatment also reduced the expressions of peritoneal fibrosis markers (Smad2, p-Smad2 and [Formula: see text]-SMA) and apoptosis markers (Caspase3, cleaved-Caspase3 and Bax) and restored the expressions of mitochondrial synthesis proteins (PGC-1[Formula: see text], NRF1 and TFAM) in ATS-treated peritoneal tissues or PMCs. Furthermore, in the presence of PGC-1[Formula: see text] inhibition, the protective effect of ATS on PF was blocked. In conclusion, ATS treatment may be an effective therapeutic agent to inhibit high glucose-induced in peritoneal fibrosis through PGC-1[Formula: see text]-mediated apoptosis.

miR-15a-5p suppresses peritoneal fibrosis induced by peritoneal dialysis via targeting VEGF in rats

Aim

When peritoneal fibrosis (PF) causes ultrafiltration failure in peritoneal dialysis (PD) patients, PD has to be discontinued. Currently, there is no effective way to relieve PF. In this study, we aimed to determine whether miR-15a-5p is involved in PF and to determine the underlying mechanism.

Methods

Six normal rats were used as the control group. A uremic rat model was constructed using 5/6 nephrectomy in a Sprague–Dawley model. The uremic rats were randomly divided into PD, lentivirus-transfected, negative control, VEGFR-inhibited and gavage control groups. Except for the control group, all uremia rats received continuous PD for 28 days. In the lentivirus-transfected group, the miR-15a-5p plasmid was injected into the peritoneal cavity to upregulate miR-15a-5p expression. Axitinib was used to block vascular endothelial growth factor receptor (VEGFR) in the peritoneum. The mRNA levels of miR-15a-5p and VEGF were detected by qRT-PCR and FISH. Protein levels of VEGF, E-cadherin, collagen IV, fibronectin and α-SMA were detected by western blot and immunohistochemistry.

Results

PD leads to peritoneal thickening and fibrosis. The expression level of miR-15a-5p decreased and that of VEGF increased in the PD group than in the controls. Additionally, E-cadherin was significantly reduced while collagen IV, fibronectin and α-SMA were obviously increased in the PD group compared to controls. FISH showed that VEGF might be the target gene of miR-15a-5p. Overexpression of miR-15a-5p or inhibition of VEGFR could reverse PF.

Conclusion

miR-15a-5p may participate in the endothelial to mesenchymal transition of PF caused by PD through VEGF.

Therapeutic Options for Preservation of Residual Renal Function in Patients on Peritoneal Dialysis

Dialysis is not the ideal renal replacement therapy because it does not fully restore all kidney functions. Increasing evidence suggests that preservation of residual renal function is associated with a survival benefit, a decrease in morbidity, better nutrition, a lower level of inflammatory markers, an improved quality of life, and cost savings by obviating the need for more peritoneal dialysis exchanges and possibly by reducing the requirement for antihypertensive agents, phosphate binders, and erythropoietin. In the present article, we review the impact of residual renal function on patient outcomes and the renoprotective strategies available in patients on peritoneal dialysis.

Continuous Ambulatory Peritoneal Dialysis is Better than Automated Peritoneal Dialysis as First-Line Treatment in Renal Replacement Therapy

This article examines the roles of continuous ambulatory peritoneal dialysis (CAPD) versus automated peritoneal dialysis (APD) as first-line renal replacement therapy. To date, no high-quality large-scale randomized controlled studies have compared CAPD with APD as first-line therapy. However, a discussion on this issue is important so that nephrologists can decide and patients can have a choice of modality on which to start dialysis, especially in the context of health care economics. We review the literature and present Hong Kong as the model of a “CAPD first” policy, an appealing, cost-effective approach for any country.

An ideal renal replacement therapy should provide optimal survival, lowest possible risk for comorbidity, highest level of quality of life, and equally important, acceptable cost to society. When we consider this subject in the context that all patients should be started on one first-line modality, the data suggest that a “CAPD first” policy has all these advantages, with APD probably having the edge only with regard to patient preference. The present review highlights preservation of residual renal function, removal and balancing of sodium, incidence of peritonitis, peritoneal membrane transport status, patient rehabilitation, and financial issues in demonstrating that a “CAPD first” policy is the model that should be adopted.

Predictors of Decline of Residual Renal Function in New Peritoneal Dialysis Patients

♦ Objective

The aim of this study was to prospectively evaluate the risk factors for decline of residual renal function (RRF) in an incident peritoneal dialysis (PD) population.

♦ Design

Prospective observational study of an incident PD cohort at a single center.

♦ Setting

Tertiary-care institutional dialysis center.

♦ Participants

The study included 146 consecutive patients commencing PD at the Princess Alexandra Hospital between 1 August 1995 and 1 July 2001 (mean age 54.8 ± 1.4 years, 42% male, 34% diabetic). Patients with failed renal transplants ( n = 26) were excluded.

♦ Main Measurements

Timed urine collections ( n = 642) were performed initially and at 6-month intervals thereafter to measure RRF. The development of anuria was also prospectively recorded.

♦ Results

The mean (±SD) follow-up period was 20.5 ± 14.8 months. The median slope of RRF decline was –0.05 mL/minute/month/1.73 m2. Using binary logistic regression, it was shown that the 50% of patients with more rapid RRF loss (< –0.05 mL/min/month/1.73 m2) were more likely to have had a higher initial RRF at commencement of PD [adjusted odds ratio (AOR) 1.83, 95% confidence interval (CI) 1.39 – 2.40] and a higher baseline dialysate/plasma creatinine ratio at 4 hours (D/P creat; AOR 44.6, 95% CI 1.05 – 1900). On multivariate Cox proportional hazards model analysis, time from commencement of PD to development of anuria was independently predicted by baseline RRF [adjusted hazard ratio (HR) 0.81, 95% CI 0.60 – 0.81], D/P creat (HR 2.87, 95% CI 2.06 – 82.3), body surface area (HR 6.23, 95% CI 1.53 – 25.5), dietary protein intake (HR 2.87, 95% CI 1.06 – 7.78), and diabetes mellitus (HR 1.65, 95% CI 1.00 – 2.72). Decline of RRF was independent of age, gender, dialysis modality, urgency of initiation of dialysis, smoking, vascular disease, blood pressure, medications (including angiotensin-converting enzyme inhibitors), duration of follow-up, and peritonitis rate.

♦ Conclusions

The results of this study suggest that high baseline RRF and high D/P creat ratio are risk factors for rapid loss of RRF. Moreover, a shorter time to the onset of anuria is independently predicted by low baseline RRF, increased body surface area, high dietary protein intake, and diabetes mellitus. Such at-risk patients should be closely monitored for early signs of inadequate dialysis.

The Role of Peritoneal Dialysis as the First-Line Renal Replacement Modality

Twenty years after its introduction, peritoneal dialysis (PD) is a well-established alternative to hemodialysis (HD) as a modality of renal replacement therapy. Much debate and research is apparent in the literature, comparing hemodialysis and PD as “opposite” modalities and trying to ascertain which modality should be more optimal.

In our opinion, HD and PD are two distinct modalities, each with its own advantages and disadvantages. In addition, it is clear that for both HD and PD, rates of technique failure are high, causing patients to transfer between modalities. The question is thus not which modality is best, but rather, which flow-chart of modalities makes best use of the advantages of each modality, while avoiding its disadvantages. In this respect, HD and PD appear to be complementary modalities.

The better preservation of residual renal function, lower risk of infection with hepatitis B and C, better outcome after transplantation, preservation of vascular access, and lower costs are arguments to promote PD as a good initial treatment. When PD-related problems arise (adequacy, ultrafiltration, peritonitis, patient burnout), a timely transfer to HD has to be planned.

This editorial tries to review arguments supporting the complementary nature of both modalities, and especially the role of PD as the first-line renal replacement therapy.

Rate of Decline of Residual Renal Function in Patients on Continuous Peritoneal Dialysis and Factors Affecting It

Objective

We analyzed residual renal function (RRF) in a large number of new peritoneal dialysis (PD) patients to prospectively define the time course of decline of RRF and to evaluate the risk factors assumed to be associated with faster decline.

Study Design

Single-center, prospective cohort study.

Setting

Home PD unit of a tertiary care University Hospital.

Patients

The study included 242 patients starting continuous PD between January 1994 and December 1997, with a minimum follow-up of 6 months and at least three measurements of RRF.

Measurement

All patients had data on demographic and laboratory variables, episodes of peritonitis and the use of aminoglycoside (AG) antibiotics, temporary hemodialysis, and number of radiocontrast studies. Adequacy of PD was measured from 24-hour urine and dialysate collection and peritoneal equilibration test using standard methodology. Further data on RRF was collected every 3 to 4 months until the patient became anuric (urine volume < 100 mL/day or creatinine clearance < 1.0 mL/min) or until the end of study in December 1998.

Outcome Measure

The slope of the decline of residual glomerular filtration rate (GFR) (an average of renal urea and creatinine clearance) was the main outcome measure. Risk factors associated with faster decline were evaluated by a comparative analysis between patients in the highest and the lowest quartiles of the slopes of GFR, and a multivariate analysis using a stepwise option within linear regression and general linear models.

Results

There was a gradual deterioration of residual GFR with time on PD, with 40% of patients developing anuria at a mean of 20 months after the initiation of PD. On multivariate analysis, use of a larger volume of dialysate ( p = 0.0001), higher rate of peritonitis ( p = 0.0005), higher use of AG ( p = 0.0006), presence of diabetes mellitus ( p = 0.005), larger body mass index (BMI) ( p = 0.01), and no use of antihypertensive medications ( p = 0.04) independently predicted the steep slope of residual GFR. Male gender, higher grades of left ventricular dysfunction, and higher 24-hour proteinuria were associated with faster decline on univariate analysis only.

Conclusion

Faster decline of residual GFR corresponds with male gender, large BMI, presence of diabetes mellitus, higher grades of congestive heart failure, and higher 24-hour proteinuria. Higher rate of peritonitis and use of AG for the treatment of peritonitis is also associated independently with faster decline of residual GFR. Whether the type of PD (CAPD vs CCPD/NIPD) is associated with faster decline of residual GFR remains speculative.

Blood Pressure Control and Left Ventricular Hypertrophy in Long-Term Capd and Hemodialysis Patients: A Cross-Sectional Study

Background

It is still not clear whether hypertension and left ventricular hypertrophy (LVH) are more common in continuous ambulatory peritoneal dialysis (CAPD) than in hemodialysis (HD) patients.

Methods

To examine this subject, the indices of cardiac performance were compared between 50 HD and 34 CAPD patients. Patients were further divided into two subgroups [long-term (L) CAPD and L-HD] according to dialysis modality and duration of dialysis (more than 60 months’ duration).

Results

The blood pressure and cardiothoracic index of CAPD patients did not differ from HD patients. On average, the left atrial index was 2 mm/m2higher in HD patients than in CAPD patients. Left ventricular chamber sizes, wall thickness, and left ventricular mass index (LVMI) in patients on CAPD were similar to those of HD patients. Isovolumic relaxation time (IVRT) of CAPD patients was insignificantly less than that of HD patients (101 ± 22 and 115 ± 27 msec respectively). There was no significant difference between the two subgroups (L-HD and L-CAPD) in blood pressure, left atrial diameter, left ventricular chamber size, wall thickness, LVMI, ejection fraction, or IVRT.

Conclusion

If normovolemia and normotension are obtained by strict volume control without using antihypertensive drugs, the effects of the two modalities of chronic dialysis treatment (HD and CAPD) on cardiac structure and function are not different from each other.

Automated Peritoneal Dialysis Has Significant Effects on Systemic Hemodynamics

Objectives

Maintenance of residual renal function (RRF) is an important determinant of outcome in peritoneal dialysis patients. It remains contentious as to whether automated peritoneal dialysis (APD) leads to an increased rate of decline of RRF compared with continuous ambulatory peritoneal dialysis (CAPD). We studied whether APD was associated with significant systemic hemodynamic changes that may play a role in the accelerated loss of RRF.

Methods

As a follow-on from a previous study, 8 well-established CAPD patients underwent a 4-hour APD treatment consisting of 3 drain/fill cycles using 2 x 2.5 L 1.36% glucose and 1 x 3.86% glucose dialysate. Each dwell phase lasted 76 minutes. Blood pressure (BP) and a full range of hemodynamic variables, including pulse (HR), stroke volume (SV), cardiac output (CO), and total peripheral resistance (TPR), were measured noninvasively using continuous arterial pulse wave analysis.

Results

BP fell during 2 of the 3 drain/fill periods when dialysate was drained from the peritoneal cavity, but then rose upon instillation of dialysate fluid. The fall in BP was associated with a fall in TPR, matched by an inadequate rise in SV and CO. Over the entire study period, TPR progressively rose to +53.4% above baseline ( p = 0.032). Both SV and CO fell over the same period, to -21.1% ( p = 0.060) and -22.4% from baseline ( p = 0.037) respectively. This did not result in any significant difference between start and end BP.

Conclusions

This study demonstrates that APD is associated with significant systemic hemodynamic effects. The increased number of drain/fill cycles compared to CAPD, or the progressive rise in TPR and reduction in CO (possibly due to a cooling effect), may potentially be factors that adversely affect RRF in APD patients.

Serum BNP Concentration and Left Ventricular Mass in CAPD and Automated Peritoneal Dialysis Patients

Objective

To compare ultrafiltration under continuous ambulatory peritoneal dialysis (CAPD) and automated PD (APD), disclosing potential effects on serum B-type natriuretic peptide (BNP) levels and echocardiographic findings.

Patients and Methods

This cross-sectional clinical study included 32 patients on CAPD and 30 patients on APD without clinical evidence of heart failure or hemodynamically significant valvular heart disease. Peritoneal equilibration tests, BNP levels, and echocardiographic measurements were performed in each subject. BNP measurements were also performed in 24 healthy control subjects.

Results

Patients on APD had lower ultrafiltration and higher values of BNP and left ventricular mass index (LVMI) compared with patients on CAPD (respectively: 775 ± 160 vs 850 ± 265 mL, p = 0.01; 253.23 ± 81.64 vs 109.42 ± 25.63 pg/mL, p = 0.001; 185.12 ± 63.50 vs 129.30 ± 40.95 g/m2, p = 0.001). This occurred despite higher mean dialysate glucose concentrations and far more extensive use of icodextrin in the APD group.

Conclusion

Treatment with APD is associated with higher plasma BNP levels and LVMI compared to CAPD. This may be the result of chronic fluid retention caused by lower ultra-filtration in APD patients.

Prescribing high-quality peritoneal dialysis: The role of preserving residual kidney function

Maintenance of residual kidney function (RKF) is independently associated with increased survival in patients with end-stage renal disease. Presence of RKF is also associated with improved volume status, better nutritional status, reduced erythropoietin requirement, and decreased rate of peritonitis in patients on peritoneal dialysis (PD). Thus, the preservation of RKF is an important therapeutic end point in the management of patients on PD. Measurement of RKF in PD patients should be based on the mean of 24-h urinary creatinine and urea clearances, and ideally, this should be done quarterly. Compared to those started on hemodialysis, patients initiated on PD appear to have slower decline in RKF. The choice of PD modality should be based on patient preference, as there is no clear evidence to date showing one modality is superior than the other in preserving RKF. Peritoneal dialysates with neutral pH and low glucose degradation products seem to have a favorable effect on RKF. An angiotensin-converting enzyme inhibitor or angiotensin receptor blocker should be used whenever possible to preserve RKF and reduce cardiac mortality. Both loop diuretics and icodextrin can be utilized to maintain fluid balance in PD patients. However, caution should be taken to avoid volume depletion which could accelerate RKF decline. Short-term use of aminoglycosides does not have a detrimental impact on RKF, but prolonged use (>3 weeks) should be avoided to minimize the risk of ototoxicity. Lastly, potential nephrotoxic agents such as intravenous contrast should be used judiciously.

The Effect of Automated versus Continuous Ambulatory Peritoneal Dialysis on Mortality Risk in China

Background

There is an emerging practice pattern of automated peritoneal dialysis (APD) in China. We report on outcomes compared to continuous ambulatory peritoneal dialysis (CAPD) in a Chinese cohort.

Methods

Data were sourced from the Baxter Healthcare (China) Investment Co. Ltd Patient Support Program database, comprising an inception cohort commencing PD between 1 January 2005 and 13 August 2015. We used time-dependent cause-specific Cox proportional hazards and Fine-Gray competing risks (kidney transplantation, change to hemodialysis) models to estimate relative mortality risk between APD and CAPD. We adjusted or matched for age, gender, employment, insurance, primary renal disease, size of PD program, and year of dialysis inception. We used cluster robust regression to account for center effect.

Results

We modeled 100,351 subjects from 1,178 centers over 240,803 patient-years. Of these, 368 received APD at some time. Compared with patients on CAPD, those on APD were significantly younger, more likely to be male, employed, self-paying, and from larger programs. Overall, APD was associated with a hazard ratio (HR) for death of 0.79 (95% confidence interval [CI] 0.64 – 0.97) compared with CAPD in Cox proportional hazards models, and 0.76 (0.62 – 0.95) in Fine-Gray competing risks regression models. There was prominent effect modification by follow-up time: benefit was observed only up to 4 years follow-up, after which risk of death was similar.

Conclusion

Automated peritoneal dialysis is associated with an overall lower adjusted risk of death compared with CAPD in China. Analyses are limited by the likelihood of important selection bias arising from group imbalance, and residual confounding from unavailability of important clinical covariates such as comorbidity and Kt/V.

Advances in Understanding and Management of Residual Renal Function in Patients with Chronic Kidney Disease

BACKGROUND

Residual renal function (RRF), defined as the ability of native kidneys to eliminate water and uremic toxins, is closely correlated with mortality and morbidity rates among patients receiving either peritoneal dialysis (PD) or hemodialysis (HD) via continuous clearance of middle-sized molecules and protein-bound solutes. Therefore, preserving RRF is considered to be one of the primary goals in managing patients with end-stage renal disease (ESRD).

SUMMARY AND KEY MESSAGES

In this article, we provide a review on the understanding and management of RRF in patients on dialysis. RRF may be estimated and measured by calculating the mean 24-hour urine creatinine level and urea clearance. Currently, several middle-sized molecules are reported but rarely used in practice. Many risk factors such as original renal diseases, dietary intake, and nephrotoxic agents impair RRF. Targeting such factors may halt the decline in RRF and offer better outcomes for patients on PD or HD. Except for in PD patients, RRF is a powerful predictor of survival in HD patients. RRF requires more clinical and research attention in the care of patients with ESRD on dialysis.

Preservation of residual kidney function in hemodialysis patients: reviving an old concept

Residual kidney function (RKF) may confer a variety of benefits to patients on maintenance dialysis. RKF provides continuous clearance of middle molecules and protein-bound solutes. Whereas the definition of RKF varies across studies, interdialytic urine volume may emerge as a pragmatic alternative to more cumbersome calculations. RKF preservation is associated with better patient outcomes including survival and quality of life and is a clinical parameter and research focus in peritoneal dialysis. We propose the following practical considerations to preserve RKF, especially in newly transitioned (incident) hemodialysis patients: (1) periodic monitoring of RKF in hemodialysis patients through urine volume and including residual urea clearance with dialysis adequacy and outcome markers such as anemia, fluid gains, minerals and electrolytes, nutritional, status and quality of life; (2) avoidance of nephrotoxic agents such as radiocontrast dye, nonsteroidal anti-inflammatory drugs, and aminoglycosides; (3) more rigorous hypertension control and minimizing intradialytic hypotensive episodes; (4) individualizing the initial dialysis prescription with consideration of an incremental/infrequent approach to hemodialysis initiation (e.g., twice weekly) or peritoneal dialysis; and (5) considering a lower protein diet, especially on nondialysis days. Because RKF appears to be associated with better patient outcomes, it requires more clinical and research focus in the care of hemodialysis and peritoneal dialysis patients.

Clinical Significance of the Edema Index in Incident Peritoneal Dialysis Patients

Background

Proper monitoring for volume overload is important to improve prognosis in peritoneal dialysis (PD) patients. The association between volume status and residual renal function (RRF) remains an unresolved issue. The aim of the present study was to evaluate the association between the edema index and survival or RRF in incident PD patients.

Patients and Methods

We identified all adults who underwent PD. The edema index was defined as the ratio of extracellular fluid to total body fluid. Participants with available data regarding survivorship or non-survivorship during the first year after PD initiation were included in the area under the receiver operating characteristic curve analysis. The cutoff value of the edema index for 1-year mortality was >0.371 in men and >0.372 in women. Participants were divided into two groups according to the cutoff value of their baseline edema indices: High (>cutoff value) and Low (≤cutoff value). Survivors during the first year after PD initiation were divided into two groups according to the initial and 1-year edema index: Non-improvement (maintenance of criteria in the initial Low group during the year) and Other (all participants except those in the Non-improvement group).

Results

In total, 631 patients were enrolled in the present study. The cutoff value of the edema index for 1-year mortality was >0.371 in men and >0.372 in women. The respective mean initial RRF values (mL·min^-1·1.73 m^-2) in the Low and High groups, respectively, were 4.88 ± 4.09 and 4.21 ± 3.28 in men (P = 0.108), and 3.19 ± 2.57 and 2.98 ± 2.70 in women (P = 0.531). There were no significant differences between groups in either sex. The respective mean RRF values at 1 year after PD initiation in the Low and High groups, respectively, were 3.56 ± 4.35 and 2.73 ± 2.53 in men, and 2.80 ± 2.36 and 1.85 ± 1.51 in women. RRF at 1 year after PD initiation was higher in the Low group than in the High group (men: P = 0.027; women: P = 0.001). In men, the cumulative 5-year survival rates were 78.7% and 46.2% in the Low and High groups, respectively, whereas in women, rates were 77.2% and 58.8% in the Low and High groups, respectively. For survivors during the first year after PD initiation, the Non-improvement group was associated with a poor survival rate compared with the Other group for both sexes.

Conclusion

A high edema index was associated with mortality in incident PD patients at baseline and follow-up. The edema index may be used as a new marker for predicting mortality in PD patients.

Risk factors for loss of residual renal function in children treated with chronic peritoneal dialysis

In dialyzed patients, preservation of residual renal function is associated with better survival, lower morbidity, and greater quality of life. To analyze the evolution of residual diuresis over time, we prospectively monitored urine output in 401 pediatric patients in the global IPPN registry who commenced peritoneal dialysis (PD) with significant residual renal function. Associations of patient characteristics and time-variant covariates with daily urine output and the risk of developing oligoanuria (under 100 ml/m²/day) were analyzed by mixed linear modeling and Cox regression analysis including time-varying covariates. With an average loss of daily urine volume of 130 ml/m² per year, median time to oligoanuria was 48 months. Residual diuresis significantly subsided more rapidly in children with glomerulopathies, lower diuresis at start of PD, high ultrafiltration volume, and icodextrin use. Administration of diuretics significantly reduced oligoanuria risk, whereas the prescription of renin–angiotensin system antagonists significantly increased the risk oligoanuria. Urine output on PD was significantly associated in a negative manner with glomerulopathies (−584 ml/m²) and marginally with the use of icodextrin (−179 ml/m²) but positively associated with the use of biocompatible PD fluid (+111 ml/m²). Children in both Asia and North America had consistently lower urine output compared with those in Europe perhaps due to regional variances in therapy. Thus, in children undergoing PD, residual renal function depends strongly on the cause of underlying kidney disease and may be modifiable by diuretic therapy, peritoneal ultrafiltration, and choice of PD fluid.

Left ventricular hypertrophy and blood pressure control in automated and continuous ambulatory peritoneal dialysis patients

Hypertension, non-dipper blood pressure (BP) pattern and decrease in daily urine output have been associated with left ventricular hypertrophy (LVH) in peritoneal dialysis (PD) patients. However, there is lack of data regarding the impact of different PD regimens on these factors. We aimed to investigate the impact of circadian rhythm of BP on LVH in end-stage renal disease patients using automated peritoneal dialysis (APD) or continuous ambulatory peritoneal dialysis (CAPD) modalities. Twenty APD (7 men, 13 women) and 28 CAPD (16 men, 12 women) patients were included into the study. 24-h ambulatory blood pressure monitoring (ABPM) and transthoracic echocardiography besides routine blood examinations were performed. Two groups were compared with each other for ABPM measurements, BP loads, dipping patterns, left ventricular mass index (LVMI) and daily urine output. Mean systolic and diastolic BP measurements, BP loads, LVMI, residual renal function (RRF) and percentage of non-dippers were found to be similar for the two groups. There were positive correlations of LVMI with BP measurements and BP loads. LVMI was found to be significantly higher in diastolic non-dippers compared to dippers (140.4 ± 35.3 vs 114.5 ± 29.7, respectively, P = 0.02). RRF and BP were found to be independent predictors of LVMI. Non-dipping BP pattern was a frequent finding among all PD patients without an inter-group difference. Additionally, higher BP measurements, decrease in daily urine output and non-dipper diastolic BP pattern were associated with LVMI. In order to avoid LVH, besides correction of anemia and volume control, circadian BP variability and diastolic dipping should also be taken into consideration in PD patients.

Strategies for preserving residual renal function in peritoneal dialysis patients

Although there have been many advancements in the treatment of patients with chronic kidney disease (CKD) over the last 50 years, in terms of reducing cardiovascular risk, mortality remains unacceptably high, particularly for those patients who progress to stage 5 CKD and initiate dialysis (CKD5d). As mortality risk increases exponentially with progressive CKD stage, the question arises as to whether preservation of residual renal function once dialysis has been initiated can reduce mortality risk. Observational studies to date have reported an association between even small amounts of residual renal function and improved patient survival and quality of life. Dialysis therapies predominantly provide clearance for small water-soluble solutes, volume and acid-base control, but cannot reproduce the metabolic functions of the kidney. As such, protein-bound solutes, advanced glycosylation end-products, middle molecules and other azotaemic toxins accumulate over time in the anuric CKD5d patient. Apart from avoiding potential nephrotoxic insults, observational and interventional trials have suggested that a number of interventions and treatments may potentially reduce the progression of earlier stages of CKD, including targeted blood pressure control, reducing proteinuria and dietary intervention using combinations of protein restriction with keto acid supplementation. However, many interventions which have been proven to be effective in the general population have not been equally effective in the CKD5d patient, and so the question arises as to whether these treatment options are equally applicable to CKD5d patients. As strategies to help preserve residual renal function in CKD5d patients are not well established, we have reviewed the evidence for preserving or losing residual renal function in peritoneal dialysis patients, as urine collections are routinely collected, whereas few centres regularly collect urine from haemodialysis patients, and haemodialysis dialysis patients are at risk of sudden intravascular volume shifts associated with dialysis treatments. On the other hand, peritoneal dialysis patients are exposed to a variety of hypertonic dialysates and episodes of peritonitis. Whereas blood pressure control, using an angiotensin-converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB), and low-protein diets along with keto acid supplementation have been shown to reduce the rate of progression in patients with earlier stages of CKD, the strategies to preserve residual renal function (RRF) in dialysis patients are not well established. For peritoneal dialysis patients, there are additional technical factors that might aggravate the rate of loss of residual renal function including peritoneal dialysis prescriptions and modality, bio-incompatible dialysis fluid and over ultrafiltration of fluid causing dehydration. In this review, we aim to evaluate the evidence of interventions and treatments, which may sustain residual renal function in peritoneal dialysis patients.

Compared decline of residual kidney function in patients treated with automated peritoneal dialysis and continuous ambulatory peritoneal dialysis: a multicenter study

BACKGROUND

There is controversy concerning the compared rates of decline of residual kidney function (RKF) in patients treated with continuous ambulatory peritoneal dialysis (CAPD) and automated peritoneal dialysis (APD).

OBJECTIVES AND METHOD

Following an observational, multicenter design, we studied 493 patients initiating peritoneal dialysis (PD) in four different Spanish units. We explored the effect of the PD modality on the rate of decline of RKF and the probability of anuria during follow-up. We applied logistic regression for intention-to-treat analyses, and linear mixed models to explore time-dependent variables, excluding those affected by indication bias.

MAIN RESULTS

Patients started on APD were younger and less comorbid than those initiated on CAPD. Baseline RKF was similar in both groups (p = 0.50). Eighty-seven patients changed their PD modality during follow-up. The following variables predicted a faster decline of RKF: higher (rate of decline) or lower (anuria) baseline RKF, younger age, proteinuria, nonprimary PD, use of PD solutions rich in glucose degradation products, higher blood pressure, and suffering peritonitis or cardiovascular events during follow-up. Overall, APD was not associated with a fast decline of RKF, but stratified analysis disclosed that patients with lower baseline RKF had an increased risk for this outcome when treated with this technique (HR: 2.26, 95% CI: 1.09-4.82, p = 0.023). Moreover, the probability of anuria during follow-up was overtly higher in APD patients (HR: 3.22, 95% CI: 1.25-6.69, p = 0.002).

CONCLUSIONS

Starting PD patients directly on APD is associated with a faster decline of RKF and a higher risk of developing anuria than doing so on CAPD. This detrimental effect is more marked in patients initiating PD with lower levels of RKF.

Inflammation and myocardial damage markers influence loss of residual renal function in peritoneal dialysis patients

BACKGROUND

Residual renal function (RRF) has been identified as the most important component in dialysis adequacy and has a strong effect on clinical outcomes. This justifies any effort in understanding the mechanism behind the preservation or decline in RRF. The aim of this study was to analyze the possible association of components of cardio-renal syndrome with the rate of decline in RRF.

METHODS

A retrospective cohort study was performed in a group of prevalent adult patients on continuous ambulatory peritoneal dialysis (CAPD). Patients were analyzed at baseline and after a 30-month follow-up. Evaluations included measurements of residual renal function, dialysis adequacy parameters, cardiovascular comorbidity, and measurements of biochemical markers of cardiovascular disease (CVD) and inflammation, as well as resting electrocardiography.

RESULTS

We included 129 patients in the study who were divided into groups according to loss of RRF, considering the cut-off point as 100 mL/day of 24 h urine volume. At baseline, there were no differences between groups: patients who lost RRF showed low values of 24 h urine volume, higher levels of systolic blood pressure, N-terminal pro-brain natriuretic peptide (NT-proBNP), C-reactive protein (CRP), IL-6, and low values of serum albumin. In the multivariate analysis, age, albumin, CRP, and NT-proBNP were significant risk factors for the loss of RRF.

CONCLUSIONS

Data indicate a close relationship between heart and kidney function where chronic kidney disease (CKD) affects and is an effect of, heart function, indicative of a bi-directional influence that leads to a vicious cycle, promoting deleterious effects on both systems.

Strategies for the preservation of residual renal function in pediatric dialysis patients

In adults with end-stage renal disease (ESRD), the preservation of residual renal function (RRF) has been shown to be associated with decreased mortality and improved control of complications of chronic kidney disease. However, less is known on the benefits of RRF in the pediatric dialysis population. The purpose of this article is to review the clinical significance of RRF and to discuss strategies for the preservation of RRF in children with ESRD.

Comparative outcomes between continuous ambulatory and automated peritoneal dialysis: a narrative review

Automated methods for delivering peritoneal dialysis (PD) to persons with end-stage renal disease continue to gain popularity worldwide, particularly in developed countries. However, the endeavor to automate the PD process has not been advanced on the strength of high-level evidence for superiority of automated over manual methods. This article summarizes available studies that have shed light on the evidence that compares the association of treatment with continuous ambulatory PD or automated PD (APD) with clinically meaningful outcomes. Published evidence, primarily from observational studies, has been unable to demonstrate a consistent difference in residual kidney function loss rate, peritonitis rate, maintenance of euvolemia, technique survival, mortality, or health-related quality of life in individuals undergoing continuous ambulatory PD versus APD. At the same time, the future of APD technology appears ripe for further improvement, such as the incorporation of voice commands and expanded use of telemedicine. Given these considerations, it appears that patient choice should drive the decision about PD modality.

Effect of peritoneal dialysis modality on the 1-year rate of decline of residual renal function

PURPOSE

The effect of different peritoneal dialysis (PD) modalities on the decline in residual renal function (RRF) is unclear due to inconsistencies among studies. In particular, the effect of automated peritoneal dialysis (APD) modalities [continuous cyclic peritoneal dialysis (CCPD) and nightly intermittent peritoneal dialysis (NIPD)] on RRF has not been examined in a large cohort.

MATERIALS AND METHODS

We conducted a single-center retrospective study to investigate the association between PD modalities and decline in RRF in 142 incident PD patients [34 on CCPD, 36 on NIPD, and 72 on continuous ambulatory peritoneal dialysis (CAPD)]. RRF was measured within 2 months from PD start and at 1 year after PD initiation.

RESULTS

The RRF at 1 year after PD initiation was 1.98±2.20 mL/min/1.73 m² in CCPD patients and 3.63±3.67 mL/min/1.73 m² in NIPD patients, which were moderately lower than 4.23±3.51 mL/min/1.73 m² in CAPD patients (p=0.064). Moreover, there was no significant difference in the 1-year rate of decline of RRF between CCPD and NIPD patients, although APD patients had a faster 1-year RRF decline rate than CAPD patients (CCPD and NIPD vs. CAPD: -45.68 and -36.69 vs. 1.17%/year, p=0.045). APD was associated with a more rapid decline in RRF in patients with end-stage renal disease undergoing PD, although multivariate analysis attenuated the significance of this finding (β=-31.50; 95% CI, -63.61 to 0.62; p=0.052).

CONCLUSION

Our results suggest that CAPD might be more helpful than APD for preserving RRF during the first year of dialysis therapy, although there was no significant difference in the 1-year rate of decline of RRF between the two APD modalities.

Residual renal function in children treated with chronic peritoneal dialysis

Residual renal function (RRF) in patients with end-stage renal disease (ESRD) receiving renal replacement therapy is defined as the ability of native kidneys to eliminate water and uremic toxins. Preserved RRF improves survival and quality of life in adult ESRD patients treated with peritoneal dialysis. In children, RRF was shown not only to help preserve adequacy of renal replacement therapy but also to accelerate growth rate, improve nutrition and blood pressure control, reduce the risk of adverse myocardial changes, facilitate treatment of anemia and calcium-phosphorus balance abnormalities, and result in reduced serum and dialysate fluid levels of advanced glycation end-products. Factors contributing to RRF loss in children treated with peritoneal dialysis include the underlying renal disease such as hemolytic-uremic syndrome and hereditary nephropathy, small urine volume, severe proteinuria at the initiation of renal replacement therapy, and hypertension. Several approaches can be suggested to decrease the rate of RRF loss in pediatric patients treated with chronic peritoneal dialysis: potentially nephrotoxic drugs (e.g., aminoglycosides), episodes of hypotension, and uncontrolled hypertension should be avoided, urinary tract infections should be treated promptly, and loop diuretics may be used to increase salt and water excretion.

Comparison between the fixation of peritoneal dialysis catheters to the peritoneal wall and the conventional placement technique: clinical experience and follow-up of a new implant technique for peritoneal dialysis catheters

Peritoneal dialysis (PD) catheters often become severely dislocated, which may lead to malfunction. With the aim of preventing this complication, we have developed a simple method of fixing the catheter downwards in the peritoneal cavity (fixation technique), a technique that does not require a laparoscope. Sixteen patients were implanted using the conventional placement technique and 25 patients were implanted using the fixation technique. The location of the catheter tip was classified from grade 1 (downward, normal) to 5 (dislocated). The frequency of dislocation (defined as the extended time and/or decrease in volume when draining the PD solution) was measured for both the fixation technique and conventional placement technique. There was a significant difference in grade between the fixation technique (2.72 ± 1.01) and conventional technique (3.92 ± 1.31). The time until first dislocation was significantly different between the fixation technique (59.3 ± 48.1 days) and conventional technique (8.8 ± 14.6 days). The time until any dislocation was significantly different between the fixation technique (69.2 ± 41.9 days) and conventional technique (12.9 ± 13.7 days). Complications were not significantly different between the fixation technique and conventional technique. The fixation technique appears to be simple, safe, and useful for preventing severe dislocation and for lengthening the time until dislocation in PD patients.

Automated peritoneal dialysis in Hong Kong: there are two distinct groups of patients

AIM

To compare the clinical outcome between continuous ambulatory peritoneal dialysis (CAPD) and automated peritoneal dialysis (APD) in specific subgroups of patients.

METHODS

We reviewed the clinical outcome of 90 consecutive incident APD patients and 180 CAPD patients in our centre.

RESULTS

The median follow up was 21.9 months (inter-quartile range, 9.5 to 46.5 months). The APD group was younger and had a lower Charlson's score than the CAPD group. Furthermore, the APD group had a highly skewed distribution of the Charlson's score, indicating the possibility of two different groups of patients. Multivariate analysis showed that in addition to the treatment mode (APD vs CAPD) and Charlson's score, there was a significant interaction between the two (P = 0.043) on patient survival. For patients with Charlson's score ≤6, the APD group had a significantly better patient survival than the CAPD group (78.3% vs. 65.4% at 5 years, P = 0.039), while for patients with Charlson's score ≥7, the APD group had a worse patient survival than the CAPD group (16.3% vs. 48.4% at 5 years, P = 0.028). Similarly, Charlson's score and its interaction with treatment mode, but not the APD group per se, were independent predictors of technique survival (P = 0.013). For patients with Charlson's score ≥7, the APD group had a significantly lower technique survival than the CAPD group (8.8% vs. 34.3%, P = 0.001), while for patients with Charlson's score ≤6, the technique survival was similar (44.4% vs. 42.5%, P = 0.15). Peritonitis-free survival was 35.2% and 32.2% for APD and CAPD groups, respectively (P = 0.021), and the difference was not affected by Charlson's score.

CONCLUSIONS

Comorbid diseases had a significant interaction with the mode of PD on patient and technique survival of incident PD patients. Our result suggests that APD may offer benefit in, and only in, young patients with minimal comorbid diseases.

[Peritoneal dialysis from the beginnings up to today: which developments of the last decades were important?]

During the past years new developments in peritoneal dialysis (PD) technique have resulted in continuous improvement of patient outcome. The importance of salt and fluid balance, residual renal function and peritoneal glucose load are of increasing interest, whereas small solute clearances have lost importance. In patients with high peritoneal transport rates automated PD (APD) is indicated. However, APD can also be chosen as initial PD treatment since recent studies show comparable or even better survival as compared to continuous ambulatory PD patients. Alternative PD solutions improve peritoneal ultrafiltration (icodextrin), reduce peritoneal glucose load (amino acid solution, icodextrin) and protect the peritoneal membrane (solutions with low concentration of glucose degradation products). Infection risk can be reduced when using antibiotic creams, but resistances should be considered. Ongoing studies will clarify if non-antibiotic agents, e.g. medihoney, are effective in preventing PD-associated infections. Due to these improvements PD and hemodialysis have become equivalent treatments.

Time course of peritoneal function in automated and continuous peritoneal dialysis

BACKGROUND AND OBJECTIVES

In automated peritoneal dialysis (APD), a patient's peritoneal membrane is more intensively exposed to fresh dialysate than it is in continuous ambulatory peritoneal dialysis (CAPD). Our aim was to study, in incident peritoneal dialysis (PD) patients, the influence of APD-compared with that of CAPD-on peritoneal transport over 4 years.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

Patients were included if at least 2 annual standard permeability analyses (SPAs) performed with 3.86% glucose were available while the patient was using the same modality with which they had started PD (APD or CAPD). Patients were followed until their first modality switch. Differences in the pattern of SPA outcomes over time were tested using repeated-measures models adjusted for age, sex, comorbidity, primary kidney disease, and year of PD start.

RESULTS

The 59 CAPD patients enrolled were older than the 47 APD patients enrolled (mean age: 58 ± 14 years vs 49 ± 14 years; p < 0.01), and they had started PD earlier (mean start year: 2000 vs 2002). Over time, no differences in solute (p > 0.19) or fluid transport (p > 0.13) were observed. Similarly, free water transport (p = 0.43) and small-pore transport (p = 0.31) were not different between the modalities. Over time, patients on APD showed a faster decline in effective lymphatic absorption rate (ELAR: p = 0.02) and in transcapillary ultrafiltration (TCUF: p = 0.07, adjusted p = 0.05). Further adjustment did not change the results.

CONCLUSIONS

Compared with patients starting on CAPD, those starting on APD experienced a faster decline in ELAR and TCUF. Other transport parameters were not different over time between the groups.

Emerging importance of residual renal function in end-stage renal failure

Residual renal function (RRF) is well recognized as an important marker of outcomes in peritoneal dialysis (PD), and contributes vitally to solute clearance. Recently, its importance in hemodialysis (HD) has emerged with evidence that it is strongly associated with improved outcomes. The presence of RRF is associated with improved nutrition, reduced erythropoetin requirements, better potassium clearance, and improved quality of life. Retrospective and observational evidence is now available, which suggests that the presence of RRF is independently associated with survival and that this benefit goes beyond what is expected simply from augmentation of small solute clearance. Preservation of RRF is now considered by many to be an important aspect of dialysis strategy. Evidence in favor of one modality over another for preservation of RRF is conflicting, as are the potential benefits of biocompatible fluids in PD. In HD, the evidence in favor of biocompatible membranes is stronger. Emerging evidence is broadly in favor of angiotensin converting enzyme inhibitors for preservation of RRF. Diuretics appear to have a neutral effect. The complexities and practical difficulties in measurement of RRF have resulted in this important parameter being largely ignored in HD. Novel markers of renal function may provide alternative, simple methods of estimating RRF, which may remove the need for urine collections and simplify its measurement.

Definition and risk factors of rapidly declining residual renal function in peritoneal dialysis: an observational study

BACKGROUND

It is critical to preserve residual renal function (RRF) in peritoneal dialysis (PD), as RRF is associated with lower morbidity and mortality. There is no uniform definition of RRF, and rapidly declining RRF has rarely been studied and predominately limited to single factor analysis and not corrected for lead-time bias.

METHODS

An observational study in 71 incident PD patients. RRF was defined as urine output (UO) ≥500 ml/day and renal glomerular filtration rate (rGFR) ≥2 ml/min/1.73 m(2), rapid declining RRF as UO <500 ml/day and rGFR <2 ml/min/1.73 m(2) occurring within 6 months which were separately evaluated. Independent risk factors associated with rapid RRF decline were identified while correcting for lead-time bias.

RESULTS

RRF declined rapidly by both definitions in 65% patients 2.5 years after PD start. Both definitions of RRF decline were consistent in 96%. Nephrotoxic drugs, renal transplant failure and absent angiotensin-converting enzyme inhibitors (ACEI) or angiotensin II receptor blockers (ARB) were independent risk factors associated with rapidly declining RRF defined both by definitions, intravascular radiocontrast additionally for UO decline.

CONCLUSIONS

Most PD patients demonstrated rapid RRF decline, independent of its definition. Both definitions are highly consistent and interchangeable. Nephrotoxic drugs and radiocontrast were identified as risk factors of acute, absent ACEI or ARB, and renal transplant failure of chronic renal injury.

Comparison of Outcomes on Continuous Ambulatory Peritoneal Dialysis versus Automated Peritoneal Dialysis: Results from a USA Database

Background and Objective

Automated peritoneal dialysis (APD) is being increasingly used as an alternative to continuous ambulatory peritoneal dialysis (CAPD). However, there has been concern regarding reduced sodium removal leading to hypertension and resulting in a faster decline in residual renal function (RRF). The objective of the present study was to compare patient and technique survival and other relevant parameters between patients treated with APD and patients treated with CAPD.

Methods

Data for incident patients were retrieved from the database of the Renal Research Institute, New York. Treatment modality was defined 90 days after the start of dialysis treatment. In addition to technique and patient survival, RRF, blood pressure, and laboratory parameters were also compared.

Results

179 CAPD and 441 APD patients were studied. Mean as-treated survival was 1407 days [95% confidence interval (CI) 1211 - 1601] in CAPD patients and 1616 days (95% CI 1478 - 1764) in APD patients. Adjusted hazard ratio (HR) for mortality was 1.31 in CAPD compared to APD (95% CI 0.76 - 2.25, p = NS). Unadjusted as-treated technique survival was lower in CAPD compared to APD, with HR 2.84 (95% CI 1.65 - 4.88, p = 0.002); adjusted HR was 1.81 (95% CI 0.94 - 3.57, p = 0.08). Peritonitis rate was 0.3 episodes/ patient-year for CAPD and APD; exit-site/tunnel infection rate was 0.1 and 0.3 episodes/patient-year for CAPD and APD respectively (p = NS).

Conclusions

Patient survival was not significantly different between APD and CAPD patients, whereas technique survival appeared to be higher in APD patients and could not be explained by differences in infectious complications. No difference in blood pressure control or decline in RRF was observed between the 2 modalities. Based on these results, APD appears to be an acceptable alternative to CAPD, although technique prescription should always follow individual judgment.

Comparison of Blood Pressure Control and Left Ventricular Hypertrophy in Patients on Continuous Ambulatory Peritoneal Dialysis (CAPD) and Automated Peritoneal Dialysis (APD)

This study aimed to investigate the influence of different peritoneal dialysis regimens on blood pressure control, the diurnal pattern of blood pressure and left ventricular hypertrophy in patients on peritoneal dialysis. Forty-four patients undergoing peritoneal dialysis were enrolled into the study. Patients were treated with different regimens of peritoneal dialysis: 26 patients on continuous ambulatory peritoneal dialysis (CAPD) and 18 patients on automated peritoneal dialysis (APD). All patients performed 24-hour ambulatory blood pressure monitoring (ABPM) and echocardiography. Echocardiography was performed for measurement of cardiac parameters and calculation of left ventricular mass index (LVMI). There were no significant differences in average of systolic and diastolic blood pressure during 24-hour, daytime, and nighttime between CAPD and APD groups. There were no significant differences in diurnal variation of blood pressure, systolic and diastolic blood pressure load, and LVMI between CAPD and APD groups. LVMI was associated with 24 hour systolic blood pressure load (r = 0.311, P < 0.05) and daytime systolic blood pressure load (r = 0.360, P < 0.05). In conclusion, this study found that there is no difference in blood pressure control, diurnal variation of blood pressure and left ventricular hypertrophy between CAPD and APD patients. The different peritoneal dialysis regimens might not influence blood pressure control and diurnal variation of blood pressure in patients on peritoneal dialysis.

Decline in residual renal function in automated compared with continuous ambulatory peritoneal dialysis

BACKGROUND AND OBJECTIVES

We compared the decline of RRF in patients starting dialysis on APD with those starting on CAPD, because a faster decline on APD has been suggested.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

NECOSAD patients starting dialysis on APD or CAPD with RRF at baseline were included and followed for 3 years. Residual GFR (rGFR) was the mean of urea and creatinine clearances. Differences in yearly decline of rGFR were estimated in analyses with linear repeated measures models, whereas the risk of complete loss of RRF was estimated by calculating hazard ratios (HRs) for APD compared with CAPD. As-treated (AT) and intention-to-treat (ITT) designs were used. All of the analyses were adjusted for age, gender, comorbidity, and primary kidney disease and stratified according to follow-up and mean baseline GFR.

RESULTS

The 505 CAPD and 78 APD patients had no major baseline differences. No differences were found in the analyses on yearly decline of rGFR. APD patients did have a higher risk of losing RRF in the first year (ITT crude HR 2.43 [confidence interval 95%, 1.48 to 4.00], adjusted 2.66 [1.60 to 4.44]; AT crude 1.89 [1.04 to 3.45], adjusted 2.15 [1.16 to 3.98]). The higher risk of losing all RRF was most pronounced in patients with the highest rGFR at baseline (ITT; crude 3.91 [1.54 to 9.94], adjusted 1.85 to 14.17).

CONCLUSIONS

The risk of losing RRF is higher for patients starting dialysis on APD compared with those starting on CAPD, especially in the first year.

In younger dialysis patients, automated peritoneal dialysis is associated with better long-term patient and technique survival than is continuous ambulatory peritoneal dialysis

BACKGROUND

In the U.S. Renal Data System registry, technique and patient survival are similar with automated peritoneal dialysis (APD) and continuous ambulatory peritoneal dialysis (CAPD). The clinical outcomes of APD and CAPD in various age groups have not been clarified.

OBJECTIVES

We investigated whether patient and technique survival are different for incident dialysis patients treated with APD or CAPD in two age groups.

METHODS

Our retrospective study of prospectively collected data included 282 incident peritoneal dialysis (PD) patients (161 on APD, 121 on CAPD). Patients on PD for less than 3 months were excluded. The patients were divided into those less than 65 years of age and those 65 years of age or older. Overall mortality and technique failure were the primary endpoints of the study. Hazard ratios (HRs) for mortality and technique failure were calculated by the Cox proportional hazards model and were adjusted for age, sex, diabetes mellitus, initial peritoneal equilibration test (PET), weekly peritoneal and renal creatinine clearances, and PD caregiver (self or other).

RESULTS

The characteristics and clinical data were not significantly different between patients on APD and CAPD, except for age and sex. The adjusted risk for overall mortality was not different between patients on APD and CAPD (HR: 0.72; 95% CI: 0.44 to 1.20; p = 0.207). The adjusted risk for technique failure was lower in APD patients than in CAPD patients (HR: 0.58; 95% CI: 0.34 to 0.98; p = 0.041). In patients less than 65 years of age, those on APD had a significantly lower risk of mortality (HR: 0.35; 95% CI: 0.16 to 0.75; p = 0.007) and technique failure (HR: 0.52; 95% CI: 0.28 to 0.95; p = 0.034) than did those on CAPD. In patients 65 years of age and older, those on APD had risks for mortality (HR: 1.14; 95% CI: 0.53 to 2.46; p = 0.730) and technique failure (HR: 0.51; 95% CI: 0.17 to 1.50; p = 0.220) that were similar to those of patients on CAPD. Nutrition status, including serum albumin and protein catabolic rate, was not significantly different between patients on APD and on CAPD, in either younger or older patients.

CONCLUSIONS

Younger Chinese patients on APD have better patient and technique survival than do those on CAPD. However, there is a strong possibility that this benefit may be confounded or accounted for by baseline differences between the APD and CAPD populations.

Strategies for improving long-term survival in peritoneal dialysis patients

The incidence and prevalence of ESRD in the United States continues to increase. Currently there are over 26,000 patients maintained on peritoneal dialysis. Mortality rates have fallen over the past several years, but long-term survival remains poor, with only 11% of peritoneal dialysis patients surviving past 10 years. Cardiovascular disease accounts for most deaths, and dialysis patients have many traditional and nontraditional cardiovascular risk factors. Lowering of these risk factors has not resulted in reduced cardiovascular morbidity and mortality in dialysis patients. Maneuvers to improve long-term peritoneal dialysis patient survival must therefore focus on modifiable risk factors including residual renal function, peritoneal membrane integrity, rate of infections, and peritoneal dialysis center size. This article reviews strategies for preserving residual renal function and peritoneal membrane integrity as well as strategies for reducing the rate of infections to enhance long-term survival in peritoneal dialysis patients.

Similar survival on automated peritoneal dialysis and continuous ambulatory peritoneal dialysis in a large prospective cohort

BACKGROUND AND OBJECTIVES

Automated peritoneal dialysis (APD) is increasingly used in comparison with continuous ambulatory peritoneal dialysis (CAPD). Although APD is expected to improve survival, convincing evidence of major advantages is lacking. The objective was to investigate whether overall mortality and technique failure of incident dialysis patients treated with APD are different from those treated with CAPD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Patients on APD or CAPD at 3 mo after start of dialysis were selected from a prospective multicenter cohort study in incident dialysis patients (NECOSAD). Overall mortality was studied with an intention-to-treat design; the event was death. Technique failure was studied with an as-treated design; the event was a switch of dialysis modality. Hazard ratios (HRs) were calculated with a follow-up of 5 yr. The HRs were adjusted for gender, age, primary kidney disease, comorbidity, residual GFR, urine production and plasma albumin at 3 mo after inclusion.

RESULTS

Eighty-seven APD and 562 CAPD patients were included. In the intention-to-treat analysis 154 CAPD and 21 APD patients died. The crude HR for overall mortality was 0.98 (95% CI: 0.62-1.54), the adjusted HR was 1.09. In the as-treated analysis 238 CAPD and 34 APD patients switched therapy, whereas 91 CAPD and 7 APD patients died. The crude HR for technique failure was 0.92 (95% CI: 0.64-1.31) and did not change after adjustment.

CONCLUSIONS

No difference was found in overall mortality and technique failure for APD compared with CAPD in incident dialysis patients.

Benefits of biocompatible PD fluid for preservation of residual renal function in incident CAPD patients: a 1-year study

BACKGROUND

In vitro studies of peritoneal dialysis (PD) solutions demonstrated that a biocompatible 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 investigated the effects of the biocompatible solution on residual renal function (RRF). We performed a prospective, randomized trial with patients starting continuous ambulatory peritoneal dialysis (CAPD).

METHODS

Ninety-one incident patients started CAPD for 12-month treatment with either LF (Balance, Fresenius, n = 48) or CF (CAPD/DPCA, Fresenius, n = 43). RRF, peritoneal solute transport rate and solute clearance were measured every 6 months.

RESULTS

LF had a significant effect on the change of glomerular filtration rate (GFR) (P = 0.048 by the mixed model). In per-protocol analysis, GFR in the LF group did not decrease over a 12-month period, while GFR in the control group significantly decreased (0.13 +/- 33.4 L/ week/1.73 m(2) for LF versus -13.6 +/- 19.4 L/week/1.73 m(2) for CF, P = 0.049). Subgroup analysis for patients with initial GFR of 2 mL/min/1.73 m(2) or above showed a significantly higher GFR for the LF group over the 12-month period. At Month 13, serum total CO(2) levels were higher and serum albumin levels were lower in the LF group. No differences between the two groups were observed for the C-reactive protein. Over the 12-month period, effluent cancer antigen-125 levels significantly increased in the LF group, compared with those of the CF group, while effluent interleukin-6 levels were not different between the two groups.

CONCLUSION

Our study suggests that LF may better preserve RRF over the 12-month treatment period in incident CAPD patients.

Long-Term Outcomes in Automated Peritoneal Dialysis: Similar or Better than in Continuous Ambulatory Peritoneal Dialysis?

In many parts of the world, a progressively larger proportion of chronic peritoneal dialysis (PD) patients are being treated with automated PD (APD). Increasingly, the decision to use APD is being dictated by patient and physician preference rather than being based on medical considerations. It is important to determine if the PD modality has any effect on long-term patient outcomes. Studies examining the effects of APD on residual renal function have been inconsistent, and the effect of cycler use on native renal clearances, if any, is small and probably not clinically significant. The preponderance of the evidence suggests that peritonitis rates are somewhat lower in APD patients than in patients treated with continuous ambulatory PD (CAPD). Two of three recent studies indicated that the risk for transfer to maintenance hemodialysis may be lower in APD patients, particularly in the early period after starting chronic PD. However, the risk for death in patients treated with CAPD and APD appears to be similar in most of the studies that have looked at that question. In summary, the long-term outcomes of CAPD and APD appear to be similar, and patient and physician preference are likely to increase the utilization of APD in many parts of the world.

Different treatment options in peritoneal dialysis

Patients with end-stage renal disease (ESRD) are placed on dialysis while they await kidney transplantation. The mortality rate among patients with ESRD is high. This review outlines the importance of preservation of residual renal function (RRF) and supports the idea of the integrated care approach to uraemia where patients start on peritoneal dialysis (PD).