Peritoneal Equilibration Test Research Articles

#2055 Variations in free water transport condition ultrafiltration capacity since basal times

Abstract Background and Aims There is great variability in free water carrying capacity (FFWC) in incident patients, but the extent to which this variability impacts inherent ultrafiltration failure (UF) is unknown. The peritoneal equilibration test (PET) with 3.86% glucose allows measurement of permeability (D/Pcr), standard UF (UFs) and sodium screening (CriNa) as an indirect measure of TAL. Our objectives were to determine to what extent variations in free water transport condition a related ultrafiltration failure. To assess, according to the variables studied, whether or not the patient`s comorbidities or anthropometric data influenced our study. Method We conducted a study in 58 incident patients in our hospital between 2009-2023 in which we evaluated D/Pcr, UFs and CriNa in PET -3.86. We recorded the dialysis pattern and daily UF. Results The PET -3.86% results were evaluated (Table 1), showing the clinical and peritoneal transport characteristics of the total patients and the comparison between patients with CriNa lower or higher than the median. The patients with lower CriNa were older and had lower UFs and UFd. We found a correlation between CriNa and UFs (0.39, p = 0.002) and daily UF (0.318, p = 0.05). In the multiple regression analysis, CriNa and D/Pcr maintain the correlation with UFs independently. While only CriNa maintains the correlation with daily UF, despite there being no differences in the use of DPA or icodextrin. Conclusion On analyzing the results, we found that the intrinsic variations of the membrane, in the free water transport capacity, justify part of the ultrafiltration capacity measured both in kinetics and daily ultrafiltration. As for age, we found that the older the patient is, the lower the sodium sieving, at least initially. With this study we emphasize the importance of assessing variations in free water transport capacity using the peritoneal equilibrium test as a tool.

The relationship between peritoneal membrane permeability and dyspepsia in peritoneal dialysis patients.

The aim of this study is to determine whether there is a relationship between peritoneal membrane permeability and dyspepsia in peritoneal dialysis patients. This study included 95 peritoneal dialysis patients aged 18 and older. The presence of dyspepsia in patients was recorded according to the 2016 ROME-IV Functional Dyspepsia Diagnostic Criteria. Subsequently, the Glasgow Dyspepsia Severity Score questionnaire was administered to assess the severity of dyspepsia. Endoscopy was performed for those who agreed to exclude organic pathology, or the results of endoscopy conducted within the last 2years were recorded. Furthermore, stool samples were examined for H. pylori to exclude organic causes of dyspepsia. PET (peritoneal equilibration test) and Kt/V values of patients were calculated using the "PD Adequest" computer software. PET values were categorized as low and low-normal for low permeability and high and high-normal for high permeability. Dyspepsia was detected in 51.6% of all peritoneal dialysis patients. H. pylori was found positive in 11.6% of all patients and 12.2% of those with dyspeptic symptoms. There was no significant difference in the rate of H. pylori occurrence between low and high permeability groups. The Glasgow Dyspepsia Severity Score did not differ significantly between H. pylori-positive and -negative patients. Dyspepsia was more frequent and severe in the low permeability group. Dyspepsia in the low permeability group was mostly considered as functional dyspepsia due to the predominance of normal endoscopic findings. Dyspepsia is a common health problem in approximately half of peritoneal dialysis patients. Dyspepsia observed in those with low peritoneal membrane permeability is generally of functional origin. Furthermore, the frequency and severity of dyspepsia are higher in individuals with low permeability. When planning peritoneal dialysis for these patients, the current status should be taken into consideration, and patients should be informed about necessary precautions and recommendations.

#2784 Deep learning algorithm predicts individual ultrafiltration trajectories for patients on automated peritoneal dialysis 12 weeks ahead

Abstract Background and Aims Adequate small solute clearance and ultrafiltration (UF) are the main requirements for fluid and salt homeostasis on peritoneal dialysis (PD). New automated peritoneal dialysis (APD) systems that allow remote patient monitoring in terms of PD treatment analysis have the potential to improve clinical outcomes. UF on APD although dependent on PD prescription, i.e. fill volumes and glucose concentration, exhibits substantial intra- and interindividual variation, even day-by-day. As conventional statistical methods are not able to assess these complex non-linear relationships adequately, we aimed to build a deep learning algorithm to predict ultrafiltration trajectories of individual patients 12 weeks ahead. Method Data on daily UF and PD prescriptions (i.e., glucose concentration, fill volumes) was extracted from the APD cycler management software (PD Link, Baxter, IL, USA) and patient charts at the Medical University of Vienna, for a secondary analysis of this cohort. The Keras high-level API for TensorFlow in R software (R Core Team 2023) was used to create a Long Short-Term Memory (LSTM) recurrent neural network based on historic prescription and gcUF data of 26 weeks (after the first 90 days of APD) to predict individual UF trajectories for the following 12 weeks. Results APD machine readouts from a total of 123 patients, with a mean time on PD of 117 (±73) days, were retrieved. The final recurrent neural network consisted of four LSTM layers with 64 cells each, sigmoid activation. The final model was fit using 30 epochs, 49 steps per epoch, and recurrent dropout to avoid overfitting. A 40-40-20% data split was used to train, validate, and test the model adequately. This deep learning algorithm was able to predict individual UF values, for each day of the upcoming 12 weeks, with an accuracy of at mean 201ml. Upon visual inspection, predicted individual UF trajectories smoothly resemble the overall day-by-day trajectory of the patient but fail to account for extreme spikes in either direction. Conclusion In conclusion, historic daily APD cycler and prescription data in coalescence with respective daily measurements of membrane function (i.e., gcUF) can be used to predict individual daily ultrafiltration values and trajectories of APD patients 12 weeks ahead using a deep learning algorithm. Therefore, continuous collection of PD prescription data and UF measurements may be used to monitor peritoneal membrane function of patients on APD and alert clinical teams upon detection of relevant changes of UF trajectories already 12 weeks ahead to facilitate early intervention. In contrast to current “screening” methods on PD, i.e., Peritoneal Equilibrium Test, these methods could reduce treatment burden.

Sodium removal per ultrafiltration volume in automated peritoneal dialysis in pediatric patients.

The standard rate of sodium removal in adult anuric patients on continuous ambulatory peritoneal dialysis (CAPD) is 7.5g/L of ultrafiltration volume (UFV). Although automated PD (APD) is widely used in pediatric patients, no attempt has yet been made to estimate sodium removal in APD. The present, retrospective cohort study included pediatric patients with APD who were managed at Tokyo Metropolitan Children's Medical Center between July 2010 and November 2017. The patients underwent a peritoneal equilibrium test (PET) at our hospital. Sodium removal per UFV was calculated by peritoneal function and dwell time using samples from patients on APD with 1- and 2-h dwell effluent within three months of PET and 4- and 10-h dwell effluent at PET. In total, 217 samples from 18 patients were included, with 63, 81, and 73 of the samples corresponding to the High [H], High-average [HA], and Low-average [LA] PET category, respectively. Sodium removal per UFV (g/L in salt equivalent) for dwell times of one, two, four, and ten hours was 5.2, 8.8, 8.0, and 11.5 for PET [H], 5.3, 5.8, 5.6, and 8.1 for PET [HA], and 4.6, 5.1, 5.1, and 7.1 for PET [LA], respectively. Sodium removal per UFV in pediatric APD was less than the standard adult CAPD and tended to be lower with shorter dwell times, leading to sodium accumulation. Therefore, salt intake should be restricted in combination with one or more long daytime dwells, especially in anuric patients.

Peritoneal glucose uptake reduction by sodium-glucose co-transporter 2 inhibitors in clinical peritoneal dialysis

Introduction: In peritoneal dialysis (PD), managing peritoneal glucose uptake is a clinical challenge, as the uptake leads to peritoneal ultrafiltration loss. Peritoneal expression of sodium-glucose co-transporter 2 (SGLT2) suggests that SGLT2 inhibitors, a class of antidiabetic agents, may offer a solution. Methods: In 12 PD patients, we examined the influence of dapagliflozin, an SGLT2 inhibitor, on peritoneal equilibration test. Results: The volume of drainage and the total glucose content in drainage were larger in the test with dapagliflozin than in that without dapagliflozin (2.41 ± 0.16 vs. 2.23 ± 0.20 L, p = 0.011 and 16.9 ± 3.8 vs. 14.5 ± 3.7 g, p = 0.005, respectively). Conclusion: SGLT2 inhibitors could reduce peritoneal glucose uptake and improve fluid removal in clinical PD.

Osteoprotegerin and Inflammation in Incident Peritoneal Dialysis Patients.

Objectives: Osteoprotegerin (OPG) is a member of the tumor necrosis factor receptor family involved in processes in many inflammatory states. OPG concentration is enhanced in the majority of chronic kidney disease (CKD) patients and those undergoing renal replacement therapy. The aim of the study was to assess the relation of OPG and chronic inflammation in peritoneal dialysis (PD) patients and to evaluate whether OPG concentrations in plasma and dialysate were related to plasma and dialysate levels of proinflammatory mediators (interleukin 6 (IL-6), high-sensitivity C-reactive protein (hsCRP), interleukin 33 (IL-33) and interleukin 1 receptor-like 1IL-1RL1 (IL-1RL1, sST2)). Methods: The study included 37 patients of the Peritoneal Dialysis Center, Department of Nephrology, Transplantology and Internal Medicine, Szczecin, Poland, 4-6 weeks after the onset of peritoneal dialysis therapy. During a peritoneal equilibration test, plasma (at 2 h) and dialysate (at 4 h) OPG, IL-33, 1IL-1RL1 (sST2), IL-6 and hsCRP concentrations were determined. Results: Plasma concentration of OPG did not correlate with dialysate OPG level (Rs = 0.04, p = 0.8). There was a strong positive correlation between plasma OPG concentrations and plasma IL-1RL1 (sST2) (Rs = 0.41; p = 0.01), plasma IL-6 (Rs = 0.38; p = 0.01) and plasma hsCRP (Rs = 0.35; p = 0.02). Dialysate OPG concentrations were positively associated with dialysate IL-1RL1 (sST2) (Rs = 0.37; p = 0.02) and dialysate IL-6 levels (Rs = 0.44; p = 0.005). Multivariate analysis showed that higher IL-1RL1 (sST2) (ß = +0.38, p = 0.006), higher plasma hsCRP (ß = +0.32, p = 0.02) and older age (ß = +0.35, p = 0.01) were independent determinants of higher plasma OPG concentration and that higher concentrations of dialysate IL-6 (ß = +0.37, p = 0.02) were independent determinants of higher dialysate OPG concentration. Conclusions: Both plasma and dialysate OPG levels are associated with the severity of systemic and local inflammation illustrated by the plasma and dialysate concentrations of IL-1RL1 (sST2), hsCRP and IL-6, suggesting that OPG might have a pivotal role in explaining the milieu of systemic and intraperitoneal inflammation.

Correlation Between the 8-hydroxy-2'-deoxyguanosine Levelin the Peritoneal Solution of Patients Undergoing PeritonealDialysis and the Peritoneal Equilibration Test, Kt/V, Ferritin,and Albumin Levels.

Peritoneal dialysis (PD) is an effective treatment modality for advanced kidney failure, offering patients a significant degree of independence. However, the long-term use of PD is limited due to the degeneration of the peritoneal membrane, resulting in reduced dialysis adequacy. Evaluating the peritoneal membrane condition in patients with advanced kidney failure who are undergoing PD is challenging with existing methods. Therefore, this study aimed to investigate the correlation between 8-hydroxy-2'-deoxyguanosine (8OHDG) levels in the peritoneal solution of patients undergoing PD and various factors, such as peritoneal equilibration test (PET), dialysis adequacy (Kt/V), underlying diseases, serum ferritin, and albumin levels. 8OHDG is a sensitive marker of oxidative stress caused by DNA damage. A total of 56 patients were included in this cross-sectional study. Five milliliters of PD fluid were collected from the patients, and 8-OHdG levels were measured using ELISA method. Then, they were compared with PET, Kt/V, albumin, and ferritin markers in the patients' files, and the results were analyzed by statistical tests. The study examined the correlation between 8OHDG and other markers. It was found that this index had significant associations with PET and underlying HTN (P < .05), whereas no significant associations were identified with the other markers. The results of the present study demonstrate that the level of 8OHDG, as one of the oxidative stress markers, could be used to evaluate the function of the peritoneum in patients undergoing PD. DOI: 10.52547/ijkd.7654.

Role of Peritoneal Equilibration Test in Assessing Folate Transport During Peritoneal Dialysis

BACKGROUNDLow plasma folate levels have been reported in patients undergoing hemodialysis and peritoneal dialysis (PD) in clinical studies. However, folate transport has never been mentioned as a factor contributing to low plasma folate levels in patients undergoing PD. The peritoneal equilibrium test (PET) assesses the plasma creatinine level and glucose transport abilities. This study aimed to evaluate the association between plasma folate levels and folate transport during PD based on PET grades. METHODSThis study recruited 50 patients who underwent PD for ≥ 3 months and were categorized according to PET grades. Data regarding plasma folate levels and dialysate folate were collected. The primary outcomes were the relationship between the PET grade and plasma folate level and between the PET grade and dialysate-to-plasma folate concentration ratio (D/P folate). Furthermore, the difference in the plasma folate level and D/P folate between men and women was assessed. RESULTSThe plasma folate level and the D/P folate significantly differed among the four PET groups (both p < 0.001). PET grade was significantly negatively correlated with plasma folate levels (r=-0.56, p < 0.001) and positively correlated with D/P folate (r=0.686, p < 0.001). In subgroup analysis, neither the plasma folate level nor the D/P folate significantly differed between men and women. CONCLUSIONSOur study provides clinical evidence that the PET grade is associated with the plasma folate level and D/P folate, regardless of sex. Larger cohort studies are warranted to assess the importance of folate supplementation during PD based on PET grades.

Predicting solute transfer rate in patients initiating peritoneal dialysis.

While assessment of membrane characteristics is fundamental to peritoneal dialysis (PD) prescription in patients initiating therapy, peritoneal equilibration test has theoretical and practical drawbacks. We wished to determine whether an equation using simple clinical variables could predict fast (above population mean) peritoneal solute transfer rate without dialysate sampling. We measured peritoneal solute transfer rate, as determined by peritoneal equilibration test using the 4-h dialysate to plasma creatinine ratio, in consecutive PD outpatients attending a single tertiary hospital for their first clinical follow-up within 3months of dialysis initiation. An equation estimating peritoneal solute transfer rate based on readily available clinical variables was generated in a randomly selected modeling group and tested in a distinct validation group. We included 712 patients, with 562 in the modeling group and 150 in the validation group. Mean age was 58.4 ± 15.9 with 431 (60.5%) men. Mean peritoneal solute transfer rate value was 0.73 ± 0.13. An equation based on gender, race, serum sodium and albumin yielded a receiving operator characteristics (ROC) area under the curve (AUC) to detect fast peritoneal solute transfer rate (> 0.73) of 0.74 (0.67-0.82). Estimated peritoneal solute transfer rate values based on percentiles 15th (> 0.66), 20th (> 0.68), 25th (> 0.69) and 30th (> 0.70) could rule out fast peritoneal solute transfer rate with negative predictive values of 100%, 93.5%, 84.2% and 80.0%, respectively. An equation based on simple clinical variables allows ruling out fast transport in a significant proportion of patients initiating PD with a high degree of confidence without requiring dialysate sampling. This could prove useful in guiding dialysis prescription of PD patients in daily clinical practice, particularly in low-resource settings.

Dapagliflozin in peritoneal dialysis patients: a pilot study evaluating peritoneal membrane function

BackgroundPatients taking SGLT-2 inhibitors may experience delayed peritoneal fibrosis, better ultrafiltration of water and toxins, and higher survival rates. We aimed to evaluate the possible effects of Dapagliflozin in changing the peritoneal solute transfer rate, reducing peritoneal glucose absorption, and, hence, increasing ultrafiltration.MethodologyA pilot pre-post interventional study was used to evaluate 20 patients on continuous ambulatory peritoneal dialysis (CAPD) enrolled in a one-month self-controlled study [Trial#: NCT04923295]. Inclusion criteria included being over 18, and having a Peritoneal Dialysis (PD) vintage of at least six months. All participants were classified as having high or average high transport status based on their Peritoneal Equilibrium Test with a D0/D4 > 0.39. and using at least two exchanges with 2.35% dextrose over the previous three months before enrollment.ResultsFollowing the treatment, 13 patients had an increase in median D4/D0 from 0.26 [0.17–0.38] to 0.31 [0.23–0.40], while seven patients had a decline from 0.28 [0.17–0.38] to 0.23 [0.14–0.33]. Additionally, nine patients had a decrease in median D/P from 0.88 [0.67–0.92] to 0.81 [0.54–0.85], while 11 patients had an increase from 0.70 [0.6–0.83] to 0.76 [0.63–0.91].ConclusionAccording to the findings of this study, Dapagliflozin usage in peritoneal dialysis patients did not result in a reduction in glucose absorption across the peritoneal membrane. Additionally, Dapagliflozin was also associated with a small increase in sodium dip, a decrease in peritoneal VEGF, and a decrease in systemic IL-6 levels all of which were not statistically significant. Further large-scale studies are required to corroborate these conclusions.

Matrix metalloproteinase-10 deficiency has protective effects against peritoneal inflammation and fibrosis via transcription factor NFκΒ pathway inhibition

One of the most common causes of discontinued peritoneal dialysis is impaired peritoneal function. However, its molecular mechanisms remain unclear. Previously, by microarray analysis of mouse peritoneum, we showed that MMP (matrix metalloproteinase)-10 expression is significantly increased in mice with peritoneal fibrosis, but its function remains unknown. Chlorhexidine gluconate (CG) was intraperitoneally injected to wild-type and MMP-10 knockout mice to induce fibrosis to elucidate the role of MMP-10 on peritoneal injury. We also examined function of peritoneal macrophages and mesothelial cells obtained from wild-type and MMP-10 knockout mice, MMP-10-overexpressing macrophage-like RAW 264.7 cells and MeT-5A mesothelial cells, investigated MMP-10 expression on peritoneal biopsy specimens, and the association between serum proMMP-10 and peritoneal solute transfer rates determined by peritoneal equilibration test on patients. MMP-10 was expressed in cells positive for WT1, a mesothelial marker, and for MAC-2, a macrophage marker, in the thickened peritoneum of both mice and patients. Serum proMMP-10 levels were well correlated with peritoneal solute transfer rates. Peritoneal fibrosis, inflammation, and high peritoneal solute transfer rates induced by CG were all ameliorated by MMP-10 deletion, with reduction of CD31-positive vessels and VEGF-A-positive cells. Expression of inflammatory mediators and phosphorylation of NFκΒ subunit p65 at S536 were suppressed in both MMP-10 knockout macrophages and mesothelial cells in response to lipopolysaccharide stimulation. Overexpression of MMP-10 in RAW 264.7 and MeT-5A cells upregulated pro-inflammatory cytokines with phosphorylation of NFκΒ subunit p65. Thus, our results suggest that inflammatory responses induced by MMP-10 are mediated through the NFκΒ pathway, and that systemic deletion of MMP-10 ameliorates peritoneal inflammation and fibrosis caused by NFκΒ activation of peritoneal macrophages and mesothelial cells.

The Peritoneal Membrane and its Role in Peritoneal Dialysis.

A healthy and functional peritoneal membrane is key to achieve sufficient ultrafiltration and to restore fluid balance, a major component of high-quality prescription in patients treated with peritoneal dialysis (PD). Variability in membrane function at the start of PD or changes over time on treatment influence dialysis prescription and outcomes, and dysfunction of the peritoneal membrane contributes to fluid overload and associated complications. In this review, we summarize the current knowledge about the structure, function and pathophysiology of the peritoneal membrane with a focus on clinical implications for patient-centered care. We also discuss the molecular and genetic mechanisms of solute and water transport across the peritoneal membrane, including the role of aquaporin water channels in crystalloid vs. colloid osmosis; why and how to assess membrane function using peritoneal equilibration tests; the etiologies of membrane dysfunction and their specific management; and the impact of genetic variation on membrane function and outcomes in patients treated with PD. This review also identifies the gaps in current knowledge and perspectives for future research to improve our understanding of the peritoneal membrane and, ultimately, to improve the care of patients treated with PD.

Partial replacement of d-glucose with d-allose ameliorates peritoneal injury and hyperglycaemia induced by peritoneal dialysis fluid in rats.

Peritoneal dialysis (PD) is a crucial dialysis method for treating end-stage kidney disease. However, its use is restricted due to high glucose-induced peritoneal injury and hyperglycaemia, particularly in patients with diabetes mellitus. In this study, we investigated whether partially replacing d-glucose with the rare sugar d-allose could ameliorate peritoneal injury and hyperglycaemia induced by peritoneal dialysis fluid (PDF). Rat peritoneal mesothelial cells (RPMCs) were exposed to a medium containing d-glucose or d-glucose partially replaced with different concentrations of d-allose. Cell viability, oxidative stress and cytokine production were evaluated. Sprague-Dawley (SD) rats were administrated saline, a PDF containing 4% d-glucose (PDF-G4.0%) or a PDF containing 3.6% d-glucose and 0.4% d-allose (PDF-G3.6%/A0.4%) once a day for 4 weeks. Peritoneal injury and PD efficiency were assessed using immuno-histological staining and peritoneal equilibration test, respectively. Blood glucose levels were measured over 120 min following a single injection of saline or PDFs to 24-h fasted SD rats. In RPMCs, the partial replacement of d-glucose with d-allose increased cell viability and decreased oxidative stress and cytokine production compared to d-glucose alone. Despite the PDF-G3.6%/A0.4% having a lower d-glucose concentration compared to PDF-G4.0%, there were no significant changes in osmolality. When administered to SD rats, the PDF-G3.6%/A0.4% suppressed the elevation of peritoneal thickness and blood d-glucose levels induced by PDF-G4.0%, without impacting PD efficiency. Partial replacement of d-glucose with d-allose ameliorated peritoneal injury and hyperglycaemia induced by high concentration of d-glucose in PDF, indicating that d-allose could be a potential treatment option in PD.

An observational study on the effect of seasonal variation on peritoneal dialysis patients.

Background: Seasonal variation has an impact on plants, wild animals, and also human beings. Data have shown seasonal variation has a significant impact on patients' fluid status, biochemistry results, and outcomes in hemodialysis populations. The relevant data on peritoneal dialysis is scant. Methods: This was a cross sectional study. All patients followed up in our center had a peritoneal equilibration test and PD adequacy test every 6months. All the peritoneal equilibration test and PD adequacy test data were collected during December 2019 to November 2020. The monthly delivery information of the whole center was collected from 2015 to 2019. Results: There were 366 patients and 604 sets of peritoneal equilibration test and PD adequacy test results in the study. Plasma albumin and phosphate levels were higher in summer. The monthly average outdoor temperature was positively correlated with plasma albumin. There was no seasonal difference in peritoneal dialysis ultrafiltration or urine volume. The percentage of low glucose concentration (1.5%) usage was higher in summer and lower in winter. Conclusion: Plasma albumin and phosphate levels were higher in summer in PD patients. Weaker glucose peritoneal dialysis dialysate was more widely used in summer. Understanding the seasonal variation of peritoneal dialysis is helpful in individualized treatment.

Influence of peritoneal residual volume on the results of the peritoneal equilibration test. Prospective study

BackgroundCategorization of the capacity of ultrafiltration during a peritoneal equilibration test (PET) is a usual step during the monitoring of peritoneal transport characteristics of Peritoneal Dialysis (PD) patients. Quantifying the peritoneal residual volume (Vr) after the dwell preceding the PET (Vrpre) and at the end of the test (Vrpost) could help to improve the accuracy of the estimation of this variable. MethodFollowing a prospective design, we calculated Vrpre and Vrpost in 116 patients, incident or prevalent on DP, who underwent one or two (n = 27) PET with 3,86/4,25% glucose-based PD solutions and complete drainage at 60 min. We evaluated the consistency of Vr by comparing Vrpre and Vrpost, as also these two parameters in repeated tests. We scrutinized potential associations between demographic and clinical factors, on one side, and the amount of Vr on the other, as also the impact of correcting ultrafiltration during PET for Vr on the categorization of the capacity of ultrafiltration. ResultsAs a mean, Vrpost was larger than Vrpre. Consequently, correction of ultrafiltration for Vr resulted in significantly higher values than those obtained according to the standard procedure (494 vs. 449 mL, p < 0,0005). We disclosed marked inconsistencies for different estimations of Vr in the same patients (Vrpre vs Vrpost and repeated PET studies). Moreover, no demographic or clinical variable was able to predict the amount of Vr. We observed a significant deviation (>200 mL) between both methods of estimation of the capacity of utrafiltration in only 12,9% of the patients. However, 21,1% of the patients categorized as cases of ultrafiltration failure according to the standard procedure did not maintain this condition after correction for Vr. ConclusionsCorrection for Vr of the capacity of ultrafiltration during a PET carries, as a mean, a minor impact on the categorization of this parameter. However, the results of the test can be significantly affected in 12,9% of the cases. We have been unable to detect demographic or clinical predictors of Vr, which suggests a random component for the mechanics of single peritoneal exchanges. We suggest that Vr should be estimated at the time of categorizing the capacity of ultrafiltration, whenever inconsistencies during serial PET studies are detected.

Supervivencia y su relación con el tipo de transferencia de solutos de membrana peritoneal, en pacientes con enfermedad renal crónica incidentes en terapia de diálisis peritoneal en RTS Colombia entre los años 2007-2017

IntroductionIn some studies, the peritoneal solute transfer rate (PSTR) through the peritoneal membrane has been related to an increased risk of mortality. It has been observed in the literature that those patients with rapid diffusion of solutes through the peritoneal membrane (high/fast transfer) and probably those with high average transfer characterized by the peritoneal equilibrium test (PET) are associated with higher mortality compared to those patients who have a slow transfer rate. However, some authors have not documented this fact. In the present study, we want to evaluate the (etiological) relationship between the characteristics of peritoneal membrane transfer and mortality and survival of the technique in an incident population on peritoneal dialysis in RTS Colombia during the years 2007 to 2017 using a competing risk model. Materials and methodsA retrospective cohort study was carried out at RTS Colombia in the period between 2007 and 2017. In total, there were 8170 incident patients older than 18 years, who had a PET between 28 and 180 days from the start of therapy. Demographic, clinical, and laboratory variables were evaluated. The (etiological) relationship between the type of peritoneal solute transfer rate at the start of therapy and overall mortality and technique survival were analyzed using a competing risk model (cause-specific proportional hazard model described by Royston-Lambert). ResultsPatients were classified into four categories based on the PET result: slow/low transfer (16.0%), low average (35.4%), high average (32.9%), and high/fast transfer (15.7%). During follow-up, with a median of 730 days, 3025 (37.02%) patients died, 1079 (13.2%) were transferred to hemodialysis and 661 (8.1%) were transplanted. In the analysis of competing risks, adjusted for age, sex, presence of DM, HTA, body mass index, residual function, albumin, hemoglobin, phosphorus, and modality of PD at the start of therapy, we found cause-specific HR (HRce) for high/fast transfer was 1.13 (95% CI 0.98–1.30) P = .078, high average 1.08 (95% CI 0.96–1.22) P = .195, low average 1.09 (95% CI 0.96–1.22) P = .156 compared to the low/slow transfer rate. For technique survival, cause-specific HR for high/rapid transfer of 1.22 (95% CI 0.98–1.52) P = .66, high average HR was 1.10 (95% CI 0.91–1.33) P = .296, low average HR of 1.03 (95% CI 0.85–1.24) P = .733 compared with the low/slow transfer rate, adjusted for age, sex, DM, HTA, BMI, residual renal function, albumin, phosphorus, hemoglobin, and PD modality at start of therapy. Non-significant differences. ConclusionsWhen evaluating the etiological relationship between the type of peritoneal solute transfer rate and overall mortality and survival of the technique using a competing risk model, we found no etiological relationship between the characteristics of peritoneal membrane transfer according to the classification given by Twardowski assessed at the start of peritoneal dialysis therapy and overall mortality or technique survival in adjusted models. The analysis will then be made from the prognostic model with the purpose of predicting the risk of mortality and survival of the technique using the risk subdistribution model (Fine & Gray).

#5157 ESTIMATION OF RENAL KT/V FROM 24-HOUR URINE VOLUME AND UREA DISTRIBUTION VOLUME IN PERITONEAL DIALYSIS

Abstract Background and Aims Residual renal function is an important factor in peritoneal dialysis (PD) regarding technical survival and implementation of incremental therapy schemes. The aim of the retrospective study was to develop an estimation formula of renal Kt/Vurea in PD based on urine output and anthropometric data. Method In 235 adult PD patients (151 males, 84 females, median age 66 years, median BMI 26.0, diuresis &amp;gt;100 ml/day) urine output was registered together with anthropometric and lab data during the first peritoneal equilibration test. The dose of furosemide therapy was noted. Urea distribution volume calculated using the formula of DuBois. Measurement of urea in blood and urine was performed by a standard kinetic test with urease. Results 24-hour urine volume ranged from 100 to 3800 ml (median 1150 ml), similar in both sexes. Renal Kturea showed a significant linear correlation to daily urine volume (r=0.78, p&amp;lt;0.01) independent from sex and diuretic dose: renal Kturea = 5.116 + 0.0221 x 24-hour urine volume (renal Kturea in liters/week, 24-hour urine volume in ml). Urea distribution volume varied between 24 and 60 liters (median 36.4 liters), and calculated renal Kt/V ranged from 0.05 to 2.57 (median 0.84). Estimated renal Kt/V, based on the before mentioned equation divided by urea distribution volume, correlated significantly to calculated renal Kt/V (r=0.75, p&amp;lt;0.01). The goodness of fit analysis showed a mean absolute error of 0.24. The Bland-Altman Plot confirmed a tendency of over-estimation for renal Kt/V &amp;lt; 1.0 and under-estimation for higher renal Kt/V. A restriction of the analysis to 24-hour urine volume up to 1500 ml (n=142 patients, median age 69 years, BMI 25) resulted in an improvement of renal Kt/V estimation (goodness of fit analysis: mean absolute error 0.20). Conclusion The estimation of renal Kt/V in PD patients seems to be feasible utilizing 24-hour urine volume and anthropometric data.

#5768 ASSOCIATION OF HIGH SERUM PHOSPHORUS WITH INCREASED MORTALITY RISK IN PATIENTS ON PERITONEAL DIALYSIS: RESULTS FROM COLOMBIA

Abstract Background and Aims Elevated levels of serum phosphorus (PO4) in patients with kidney failure are associated with complications such as cardiovascular (CV) disease, bone disease and impaired wound healing, and increased mortality in hemodialysis patients. A recent PDOPPS study (Lopes et al NDT 2023) showed that high PO4 is associated with increased mortality also in patients undergoing peritoneal dialysis (PD). We explored PO4 levels in a large cohort of patients undergoing chronic PD in Colombia to determine the association of PO4 levels with mortality. Method In an observational study of 8113 prevalent PD patients treated with APD (n = 2692) or CAPD (n = 5421), PO4 levels together with demographic and clinical data, including dialysate to plasma ratio of creatinine at 240 min (D/PCr240min at peritoneal equilibration test) and body mass index (BMI), were recorded. During follow-up for a median of 1.99 years, 3169 patients died, and 988 patients underwent kidney transplantation (KT). We divided patients into 5 groups (P1 to P5) according to their baseline PO4 levels (first available measurement) with the following cut-off values for groups: up to 3.5, 4.5, 5.5, 6.5, and over 6.5 mg/dL, respectively. The association of baseline PO4 levels with all-cause and CV mortality risk was analyzed with a competing-risk regression model and KT as a competing risk. Results Characteristics of patients classified into groups P1 (16%), P2 (33%), P3 (27%), P4 (13%), and P5 (9%) are presented in Table. P5-patients were in general younger, more often men, less often diabetic (DM), and had lower hemoglobin (Hb) and serum albumin compared to P1-patients. All-cause mortality risk (after adjusting for age, sex, BMI, albumin, Hb, D/PCr240min, residual renal function, DM, and hypertension) was increased in P4- and P5-patients compared with P2-patients, sub-hazard ratio (sHR) of 1.14 (95% Cl: 1.01-1.27) and sHR of 1.27 (95% Cl: 1.10-1.46), respectively. Higher PO4 levels were not associated with significantly increased CV mortality risk for P4-patients, sHR of 1.10 (95% Cl: 0.93-1.31), or for P5-patients, sHR = 1.14 (95% Cl: 0.93-1.39) compared to P2-patients. Conclusion Among 8113 PD patients in Colombia, 49% had baseline PO4 &amp;gt;4.5 mg/dL and 22% PO4 &amp;gt; 5.5 mg/dL. Baseline PO4 levels &amp;gt; 5.5 mg/dL (P4 and P5 groups) were associated with increased all-cause mortality. These results are in agreement with the results of the PDOPPS study and suggest that effective management of hyperphosphatemia is important to improve clinical outcomes in PD patients.

#5668 PERITONEAL DIALYSIS ADDITIVE REDUCES TRANSPERITONEAL LOSS OF BLOOD MICROPARTICLE AND EXTRACELLULAR MATRIX PROTEINS IN A CONTROLLED CROSSOVER TRIAL

Abstract Background and Aims About 11% of patients requiring dialysis worldwide are treated with peritoneal dialysis (PD). With each PD exchange high amounts of protein are removed from the peritoneal cavity stemming from the systemic circulation (reflecting toxin removal, loss of serum proteins, inflammatory processes) and local inflammatory processes. Thereby, the clinically measured peritoneal protein loss (PPL) is the result of transperitoneal serum loss, lymphatic drainage, transmesothelial reabsorption, local production, and cellular components. Although high PPL has been found to be predictive of mortality and cardiovascular morbidity, the pathophysiological concept is still poorly understood. Method Peritoneal dialysis effluent (PDE) samples were obtained from peritoneal equilibrium tests during a prospective, multicenter, double-blinded, controlled, randomized, dual-period, 2-treatment, crossover, phase II, proof-of-concept study in Austria. PDE samples were submitted to proteomic analysis by tandem mass tag (TMT) labeling and 2D reversed phase liquid chromatography mass spectrometry. To disentangle transmembrane serum protein loss from local protein production we developed a novel and unique analytical approach. Briefly, partitioning around medoids and proximity in the Euclidean space for between visit (non-treatment visits only) single-protein kinetics was utilized to achieve this separation. A multivariate mixed-effects model was calculated to identify treatment (intraperitoneal alanyl-glutamine administration) effects. Results We identified 2,624 different proteins within the PDE of 12 patients across two time-points. A large cluster of proteins with stable abundances in collinearity with well-established clinical characteristics of transperitoneal transport (e.g., dialysate-to-plasma-albumin) in accordance with the three-pore-model was identified. After clustering and separation, the proteins resembling similar time-course kinetics to clinical transperitoneal membrane transport characteristics (one of five clusters) were all identified to be able to theoretically traverse through the small peritoneal pore (&amp;lt; 4-6 nm). Of these 549 proteins lost from the systemic circulation via transperitoneal small pore diffusion, the appearance of 51 in the PD effluent was significantly reduced by intraperitoneal administration of alanyl-glutamine. The affected proteins are mainly involved in extracellular matrix organization, part of extracellular exosome signaling and blood microparticles, e.g. high density lipoprotein (HDL) formation (Apolipoprotein A1). Conclusion PPL is an important but poorly understood undesired effect of PD associated with cardiovascular morbidity and mortality. Our novel analytical approach enables us to disentangle the complexity of transperitoneal serum protein loss and local protein production on single-protein level across the peritoneal proteome. Furthermore, we were able to delineate the potential beneficial effects of intraperitoneal alanyl-glutamine treatment on PPL and peritoneal health which might even suggest potential beneficial effects on cardiovascular morbidity (e.g., HDL formation).

#6690 THE ASSOCIATION BETWEEN SERUM CHEMERIN AND PERITONEAL MEMBRANE TRANSPORT FUNCTION IN INCIDENT PERITONEAL DIALYSIS PATIENTS: A PROSPECTIVE COHORT STUDY

Abstract Background and Aims Some biomarkers in drained dialysate or peritoneal membrane have been found related to the dialysate/plasma ratio of creatinine at 4 h (D/P Cr) in patients undergoing peritoneal dialysis (PD). But so far, there is no report on serum markers. Some biomarkers are associated with cardiovascular diseases (CVDs). Chemerin is a multifunctional chemoattractant adipokine which plays roles in inflammation, adipogenesis and metabolism. In this study, we intended to investigate the role of chemerin in the peritoneal membrane transport function and CVDs in incident PD patients. Method This prospective cohort study was conducted in our PD center. The patients underwent initial standardized peritoneal equilibration test (PET) after PD for 4–6 weeks. Level of serum chemerin was determined via enzyme-linked immunosorbent assay (ELISA). The patients’ CVDs were recorded during the follow-up period. Results 151 eligible patients with a mean age of 46.59±13.52 years were enrolled. And the median duration of PD was 25.0 months. The median concentration of serum chemerin was 29.09 ng/mL. Baseline D/P Cr was found to be positively correlated with serum chemerin (r = 0.244, p = 0.003). The multivariate analyses revealed that serum chemerin (p = 0.002), age (p = 0.041), albumin (p = 0.000), and high-density lipoprotein (HDL) (p = 0.022) were independent factors of D/P Cr. The serum chemerin level was significantly higher in diabetes mellitus (DM) patients than that of patients without DM (36.45 vs 27.37 ng/mL, p = 0.000). And there was a significant statistical difference in CVDs between the high chemerin group (≥29.09 ng/mL) and low chemerin group (&amp;lt;29.09 ng/mL) (42% vs 21%, p = 0.009). Conclusion Serum chemerin has a positive correlation with baseline D/P Cr in incident PD patients. It may be a biomarker that can predict the baseline transport function of peritoneal membrane. And serum chemerin may be a risk factor of CVDs for incident PD patients. Multicenter studies with a larger sample size are warranted in the future.