Automated peritoneal dialysis prescriptions for enhancing sodium and fluid removal: a predictive analysis of optimized, patient-specific dwell times for the day period

Clinical guideline on adequacy and prescription of peritoneal dialysis

In recent years, the meaning of adequacy in peritoneal dialysis has changed. We have witnessed a transition from an exclusive achievement of specific objectives -namely solute clearances and ultrafiltration- to a more holistic approach more focused to on the quality of life of these patients. The purpose of this document is to provide recommendations, updated and oriented to social and health environment, for the adequacy and prescription of peritoneal dialysis. The document has been divided into three main sections: adequacy, residual kidney function and prescription of continuous ambulatory peritoneal dialysis and automated peritoneal dialysis. Recently, a guide on the same topic has been published by a Committee of Experts of the International Society of Peritoneal Dialysis (ISPD 2020). In consideration of the contributions of the group of experts and the quasi-simultaneity of the two projects, references are made to this guide in the relevant sections. We have used a systematic methodology (GRADE), which specifies the level of evidence and the strength of the proposed suggestions and recommendations, facilitating future updates of the document.

Metabolomic profiling of overnight peritoneal dialysis effluents predicts the peritoneal equilibration test type

This study primarily aimed to evaluate whether peritoneal equilibration test (PET) results can be predicted through the metabolomic analysis of overnight peritoneal dialysis (PD) effluents. From a total of 125 patients, overnight PD effluents on the day of the first PET after PD initiation were analyzed. A modified 4.25% dextrose PET was performed, and the PET type was categorized according to the dialysate-to-plasma creatinine ratio at the 4-h dwell time during the PET as follows: high, high average, low average, or low transporter. Nuclear magnetic resonance (NMR)-based metabolomics was used to analyze the effluents and identify the metabolites. The predictive performances derived from the orthogonal projection to latent structure discriminant analysis (OPLS-DA) modeling of the NMR spectrum were estimated by calculating the area under the curve (AUC) using receiver operating characteristic curve analysis. The OPLS-DA score plot indicated significant metabolite differences between high and low PET types. The relative concentrations of alanine and creatinine were greater in the high transporter type than in the low transporter type. The relative concentrations of glucose and lactate were greater in the low transporter type than in the high transporter type. The AUC of a composite of four metabolites was 0.975 in distinguish between high and low PET types. Measured PET results correlated well with the total NMR metabolic profile of overnight PD effluents.

Research hotspots and emerging trends of automated peritoneal dialysis: A bibliometric analysis from 2000 to 2020

BACKGROUND

The implementation of automated peritoneal dialysis (APD) has considerably increased in many countries. We conducted a bibliometric analysis to evaluate the accumulating studies on APD in the last two decades quantitatively and qualitatively.

METHODS

Publications regarding APD research between 2000 and 2020 were retrieved from the Web of Science Core Collection database by using the index term "automated peritoneal dialysis." CiteSpace, VOSviewer, and an online platform were employed to analyze the number of publications and the collaboration relationships between countries, institutions, authors, and co-cited journals. Cluster analysis and burst keywords detection were performed on co-cited references and keywords, respectively.

RESULTS

We obtained a record of 545 publications related to APD in total. The United States was the country that contributes most, and Baxter Healthcare Corporation was the leading institution. Peritoneal Dialysis International was the most active journals in this field. Claudio Ranco was the most productive author, and Simon J Davies ranked the first in the cited authors. Co-cited reference cluster analysis and high frequency keywords showed that survival, ultrafiltration and peritonitis are continuous hot topics. While remote monitoring (RM) and telemedicine may be APD research frontiers according to burst keywords detection.

CONCLUSION

This bibliometric study provides comprehensive overview on the publications of APD over the past two decades. These findings help to identify the hotspots and explore new directions for future research. RM has become an emerging trend in APD field.

The prognosis and risk factors of baseline high peritoneal transporters on patients with peritoneal dialysis

The relationship between baseline high peritoneal solute transport rate (PSTR) and the prognosis of peritoneal dialysis (PD) patients remains unclear. The present study combined clinical data and basic experiments to investigate the impact of baseline PSTR and the underlying molecular mechanisms. A total of 204 incident CAPD patients from four PD centres in Shanghai between 1 January 2014 and 30 September 2020 were grouped based on a peritoneal equilibration test after the first month of dialysis. Analysed with multivariate Cox and logistic regression models, baseline high PSTR was a significant risk factor for technique failure (AHR 5.70; 95% CI 1.581 to 20.548 p = 0.008). Baseline hyperuricemia was an independent predictor of mortality (AHR 1.006 95%CI 1.003 to 1.008, p < 0.001) and baseline high PSTR (AOR 1.007; 95%CI 1.003 to 1.012; p = 0.020). Since uric acid was closely related to high PSTR and adverse prognosis, the in vitro experiments were performed to explore the underlying mechanisms of which uric acid affected peritoneum. We found hyperuricemia induced epithelial‐to‐mesenchymal transition (EMT) of cultured human peritoneal mesothelial cells by activating TGF‐β1/Smad3 signalling pathway and nuclear transcription factors. Conclusively, high baseline PSTR induced by hyperuricaemia through EMT was an important reason of poor outcomes in CAPD patients.

Dialysate glucose response phenotypes during peritoneal equilibration test and their association with cardiovascular death: A cohort study

Different measures of rates of transfer of glucose during the peritoneal equilibrium test (PET), undertaken during peritoneal dialysis (PD) might provide additional information regarding a patient's risk of future cardiovascular mortality. This study aimed to characterize the heterogeneity of dialysate glucose (DG) response phenotypes during the PET and compare the cardiovascular mortality rates associated with the different phenotypes. Our cohort was derived from Henan peritoneal dialysis registry. A total of 3477 patients initiating PD in 2007 to 2014 had the DG measured at 0, 2-hour and 4-hour (D0, D2, and D4 respectively) during the PET for estimation of D2/D0 and D4/D0. Deaths mainly due to CVD within 2 years since the initiation of PD were defined as the outcome. Latent class mixed-effect models were fitted to identify distinct phenotypes of the DG response during the PET. Multivariable unconditional Logistic regression models with adjustment for cardiometabolic risk factors were used to compare the 2-year risk of cardiovascular mortality among patients in the different latent classes. Three distinct DG response phenotypes during the PET were identified. Those with consistently high D2/D0 and D4/D0 ratios had a 1.22 [95% confidence interval: 1.02, 1.35] excess risk of a cardiovascular death within 2 years of commencing PD compared with patients with the lowest D2/D0 ratio and decreased D4/D0 ratio after adjustment for cardiometabolic risk factors. Consistently elevated D2/D0 and D4/D0 ratios during the PET are associated with an increased risk of 2-year cardiovascular mortality independent of other cardiometabolic risk factors. In view of the potential bias due to unmeasured confounders (eg, Family history of cardiovascular diseases, and dietary patterns), this association should be further validated in other external cohorts.

New-Onset Diabetes Mellitus in Peritoneal Dialysis and Hemodialysis Patients: Frequency, Risk Factors, and Prognosis-A Review

New-onset diabetes mellitus (NODM) is observed in both hemodialysis (HD) and peritoneal dialysis (PD) patients. The prevalence of NODM in dialysis patients is slightly higher compared to subjects of the general population. Based on currently published data there is no convincing evidence that the risk of NODM is different between HD and PD patients. Data on the effect of glucose load on risk of NODM in dialysis patients remain controversial. PD modality (automated or continuous ambulatory PD) has no significant influence on NODM incidence. Chronic inflammation is associated with NODM in dialysis patients. Reported differences in NODM between PD and HD patients are possibly also influenced by differences in demographic factors between these patient groups. Mortality in NODM patients is lower than mortality in patients with preexisting DM. This may be partly explained by the younger age and lower number of comorbidities in patients with NODM.

Dialysate Creatinine Response Patterns During Peritoneal Equilibration Test and the Association Between Cardiovascular Mortality: Findings from a Prospective Cohort Study

BACKGROUND/AIMS

During peritoneal equilibrium test (PET), intermediate measures of Dt/P (dialysate/plasma creatinine ratio), D0/P, D2/P and D4/P ratios might provide additional information regarding a patient's cardiovascular mortality. We aimed to characterise heterogeneity of dialysate creatinine response patterns based on three ratios and compare cardiovascular mortality risks by response patterns.

METHODS

3,477 patients initialising peritoneal dialysis (PD) between 2007-2015 were measured D0/P, D2/P and D4/P at baseline and 2-year cardiovascular mortality was defined as the primary outcome. Latent class mixed-effect models were fitted to identify distinct patterns of dialysate creatinine response. Multivariable Logistic regression model with adjustment of cardiometabolic factors were used to compare cardiovascular mortality by latent classes.

RESULTS

The 1st latent class including 36% of participants was characterised by consistently increasing and high Dt/P ratios both at 2-hour and 4-hour. The 2nd class including 61% of participants characterised by sharply increased ratio at 2-hour and slightly increased ratio at 4-hour. The 3rd class included 3% of participants with decreased ratio at 2-hour and increased ratio at 4-hour. Comparing the 1st class, the lower cardiovascular mortality risk was identified in the 2nd and 3rd class with adjusted odds ratio 0.65 (95% confidence interval: 0.62-0.69) and 0.48 (0.41-0.57), respectively.

CONCLUSION

Patients with decreased Dt/P ratio between 0-hour and 2-hour and low ratios at 2-hour and 4-hour tend to have low cardiovascular mortality. Latent class analysis seems to be a promising method to reveal unidentified subgroups that do not fit into the risk category defined by Dt/P ratio at 4-hour.

Fluid Redistribution in Sleep Apnea: Therapeutic Implications in Edematous States

Sleep apnea (SA), a condition associated with increased cardiovascular risk, has been traditionally associated with obesity and aging. However, in patients with fluid-retaining states, such as congestive heart failure and end-stage renal disease, both prevalence and severity of SA are increased. Recently, fluid shift has been recognized to play an important role in the pathophysiology of SA, since the fluid retained in the legs during the day shifts rostrally while recumbent, leading to edema of upper airways. Such simple physics, observed even in healthy individuals, has great impact in patients with fluid overload. Correction of the excess fluid volume has risen as a potential target therapy to improve SA, by attenuation of nocturnal fluid shift. Such strategy has gained special attention, since the standard treatment for SA, the positive airway pressure, has low compliance rates among its users and has failed to reduce cardiovascular outcomes. This review focuses on the pathophysiology of edema and fluid shift, and summarizes the most relevant findings of studies that investigated the impact of treating volume overload on SA. We aim to expand horizons in the treatment of SA by calling attention to a potentially reversible condition, which is commonly underestimated in clinical practice.

Effect of Icodextrin Solution on the Preservation of Residual Renal Function in Peritoneal Dialysis Patients: A Randomized Controlled Study

Although icodextrin solution has been highlighted in the fluid management compared to glucose-based solutions, proof of a beneficial effect of icodextrin solution on residual renal function (RRF) is lacking. We conducted a multicenter prospective randomized controlled open-label trial to investigate whether icodextrin solution can preserve RRF.One hundred patients with urine volume ≥750 mL/day from 8 centers in Korea were randomly assigned to receive 1 exchange of icodextrin solution for a ≥8 hour-dwell time and 2 exchanges of 1.5% glucose-based biocompatible neutral pH solution or 1 exchange of ≥2.5% and 2 exchanges of 1.5% glucose-based biocompatible solutions. Using mixed-effects general linear models, we analyzed changes in residual glomerular filtration rate (GFR) and daily urine volume at 1 year.Forty-nine patients were assigned to the icodextrin group and 51 to the glucose solution group. During follow-up, the slope of the decline in residual GFR was -0.170 mL/min/month/1.73 m² in the icodextrin group, while it was -0.155 mL/min/month/1.73 m² in the glucose solution group (95% confidence interval [CI], -0.06 to 0.10; P = 0.701). Daily urine volume decreased faster in the glucose solution group than in the icodextrin group (-31.02 vs -11.88 mL per month; 95% CI, -35.85 to -2.44; P = 0.025). Results were consistent when we analyzed using intention-to-treat and per protocol principles. There were no differences in fluid status, peritoneal ultrafiltration, and peritoneal transport between groups during follow-up.This study clearly showed that icodextrin solution preserves residual urine volume better than glucose solution.

Peritoneal Equilibration Test and Patient Outcomes

BACKGROUND AND OBJECTIVES

Although a peritoneal equilibration test yields data on three parameters (4-hour dialysate/plasma creatinine, 4- to 0-hour dialysate glucose, and 4-hour ultrafiltration volume), all studies have focused on the prognostic value of dialysate/plasma creatinine for patients undergoing peritoneal dialysis. Because dialysate 4- to 0-hour glucose and ultrafiltration volume may be superior in predicting daily ultrafiltration, the likely mechanism for the association of peritoneal equilibration test results with outcomes, we hypothesized that they are superior to dialysate/plasma creatinine for risk prediction.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We examined unadjusted and adjusted associations of three peritoneal equilibration test parameters with all-cause mortality, technique failure, and hospitalization rate in 10,142 patients on peritoneal dialysis treated between January 1, 2007 and December 31, 2011 in 764 dialysis facilities operated by a single large dialysis organization in the United States, with a median follow-up period of 15.8 months; 87% were treated with automated peritoneal dialysis.

RESULTS

Demographic and clinical parameters explained only 8% of the variability in dialysate/plasma creatinine. There was a linear association between dialysate/plasma creatinine and mortality (adjusted hazards ratio per 0.1 unit higher, 1.07; 95% confidence interval, 1.02 to 1.13) and hospitalization rate (adjusted incidence rate ratio per 0.1 unit higher, 1.05; 95% confidence interval, 1.03 to 1.06). Dialysate/plasma creatinine and dialysate glucose were highly correlated (r=-0.84) and yielded similar risk prediction. Ultrafiltration volume was inversely related with hospitalization rate but not with all-cause mortality. None of the parameters were associated with technique failure. Adding 4- to 0-hour dialysate glucose, ultrafiltration volume, or both did not result in any improvement in risk prediction with dialysate/plasma creatinine alone.

CONCLUSIONS

This analysis from a large contemporary cohort treated primarily with automated peritoneal dialysis validates dialysate/plasma creatinine as a robust predictor of outcomes in patients treated with peritoneal dialysis.

Volume-Based Peritoneal Dialysis Prescription Guide to Achieve Adequacy Targets

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BACKGROUND

The use of automated and continuous ambulatory peritoneal dialysis (APD and CAPD) prescriptions (Rxs) to achieve adequate uremic toxin and fluid removal targets is important for attaining optimal patient outcomes. One approach for predicting such Rxs is the use of kinetic modeling. ♦

METHODS

Demographic data and peritoneal membrane characteristics derived from a peritoneal equilibration test (PET) were available from 1,005 patients in North American centers who participated in a national adequacy initiative in 1999. Twelve patient subgroups were identified according to peritoneal membrane transport type and tertiles of total body water, assumed equal to urea distribution volume (Vurea). Each patient was then modeled using PD Adequest 2.0 to be treated by 12 CAPD and 34 APD Rxs using both glucose and icodextrin solutions to achieve adequacy targets of weekly urea Kt/V of 1.7 and 1 L of daily ultrafiltration (UF). Residual kidney function (RKF) was assumed to be 0, 2, 4, and 6 mL/min. Feasible peritoneal dialysis (PD) Rxs were identified where: 1) the 95% confidence limit achieved the goal of meeting the targets for urea Kt/V, daily UF, and both in 85%, 75%, and 70% of patients, respectively; 2) average PD solution dextrose concentration was < 2.5%; and 3) the number of daytime exchanges was minimized. ♦

RESULTS

Feasible PD Rxs were similar when RKF was ≥ 2 mL/min, allowing condensed recommendations based on RKF ≥ 2 mL/min or < 2 mL/min. Individuals with lower or slower membrane transport required relatively greater 24-h solution volumes to achieve adequacy targets when RKF fell below 2 mL/min. With increasing Vurea, there was disproportionately greater dependence on RKF to achieve targets. While multiple Rxs achieving urea Kt/V and daily UF goals were identified for all membrane transport types, use of icodextrin in the long dwell reduced the need for a midday exchange in APD, glucose exposure, required fill and 24-h dwell volumes, irrespective of RKF and Vurea. While these benefits were most notable in high and high-average transporters, similar results were also seen in low and low-average transporters. ♦

CONCLUSIONS

Kinetic modeling identified multiple APD and CAPD Rxs that achieved adequate uremic solute and fluid removal for patients, irrespective of RKF and Vurea. Use of icodextrin rather than glucose in the long dwell reduced the complexity of the PD regimen, total glucose exposure, and 24-h total treatment solution volumes. Irrespective of modeling, adequacy of any PD prescription should be based upon individual clinical evaluation both for volume and solute removal.

Icodextrin Simplifies PD Therapy by Equalizing UF and Sodium Removal Among Patient Transport Types During Long Dwells: A Modeling Study

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BACKGROUND

In recent years, results from clinical studies have changed the focus of peritoneal dialysis (PD) adequacy from small solute clearance to volume control, resulting in continued efforts to improve fluid and sodium removal in PD patients. We used a modified 3-pore model to theoretically predict fluid and solute removal using glucose-based and icodextrin solutions for a wide range of transport characteristics with automated PD (APD) and continuous ambulatory PD (CAPD) therapies. ♦

METHODS

Simulations were performed for the day (APD: 15-hr, 2.27% glucose and 7.5% icodextrin; CAPD: 3x5-hr, 1.36% and 2.27% glucose) and night (APD: 9-hr, 1.36% glucose; CAPD: 9-hr, 2.27% glucose and 7.5% icodextrin) dialysis periods separately. During APD, the number of night exchanges (N) was varied from 3 to 7. Ultrafiltration (UF), sodium removal (NaR), total carbohydrate absorption (CHO), UF efficiency (UFE), and sodium removal efficiency (NaRE) were calculated. Typical patients in fast (i.e. high, H), average (high-average, HA; low-average, LA), and slow (low, L) transport groups with no residual kidney function were considered. ♦

RESULTS

The effective dwell times varied between 1.0 and 14.7 hours depending on the number of exchanges. With glucose-based solutions, differences in UF and NaR between H and L transport patients ranged from 140 mL and 2 mmol (APD night, n = 7) to 778 mL and 56.4 mmol (CAPD day, 2.27%). With icodextrin, differences in UF and NaR ranged from 1 mL and 1.1 mmol (CAPD night) to 59 mL and 6.1 mmol (APD day). The use of icodextrin resulted in greater CHO than 2.27% glucose (APD: 27.1 - 35.6 g more; CAPD: 17.1 - 17.5 g more). The UFE and NaRE were greater for all patients with icodextrin than with glucose-based solution in both therapy modalities, except for slow transport patients in CAPD. ♦

CONCLUSION

This modeling study shows that the dependence of UF and NaR on patient transport type observed with glucose-based solutions can be minimized using icodextrin during the long dwells of APD and CAPD. While this approach simplifies the PD prescription by minimizing the dependencies of ultrafiltration and sodium removal on patient transport type when using icodextrin, it improves fluid and sodium removal efficiencies in fast and average transport patients without any added glucose exposure.