Development and Validation of a Machine Learning Model Predicting Arteriovenous Fistula Failure in a Large Network of Dialysis Clinics

Background: Vascular access surveillance of dialysis patients is a challenging task for clinicians. We derived and validated an arteriovenous fistula failure model (AVF-FM) based on machine learning. Methods: The AVF-FM is an XG-Boost algorithm aimed at predicting AVF failure within three months among in-centre dialysis patients. The model was trained in the derivation set (70% of initial cohort) by exploiting the information routinely collected in the Nephrocare European Clinical Database (EuCliD®). Model performance was tested by concordance statistic and calibration charts in the remaining 30% of records. Features importance was computed using the SHAP method. Results: We included 13,369 patients, overall. The Area Under the ROC Curve (AUC-ROC) of AVF-FM was 0.80 (95% CI 0.79–0.81). Model calibration showed excellent representation of observed failure risk. Variables associated with the greatest impact on risk estimates were previous history of AVF complications, followed by access recirculation and other functional parameters including metrics describing temporal pattern of dialysis dose, blood flow, dynamic venous and arterial pressures. Conclusions: The AVF-FM achieved good discrimination and calibration properties by combining routinely collected clinical and sensor data that require no additional effort by healthcare staff. Therefore, it can potentially enable risk-based personalization of AVF surveillance strategies.

Ensuring hemodialysis adequacy by dialysis dose monitoring with UV spectroscopy analysis of spent dialyzate

Introduction: Patients’ session-to-session variation has been shown to influence outcomes, making critical the monitoring of dialysis dose in each session. The aim of this study was to detect the intra-patient variability of blood single pool Kt/V as measured from pre-post dialysis blood urea and from the online tool Adimea®, which measures the ultraviolet absorbance of spent dialyzate. Methods: This open, one-armed, prospective non-interventional study, evaluates patients on bicarbonate hemodialysis or/and on hemodiafiltration. Dialysis was performed with B. Braun Dialog+ machines equipped with Adimea®. In the course of the prospective observation, online monitoring with Adimea® in each session was established without the target warning function being activated. A sample size of 97 patients was estimated. Results: A total of 120 patients were enrolled in six centers in China (mean age 51.5 ± 12.2 years, 86.7% males, 24.2% diabetics). All had an AV-fistula. The proportion of patients with blood Kt/V < 1.20 at baseline was 48.3%. During follow-up with Adimea®, the subgroup with Kt/V > 1.20 at baseline remains at the same adequacy level for more than 90% of the patients. Those with a Kt/V < 1.20 at baseline, showed a significant increase of Kt/V to 60% of the patients reaching the adequacy level >1.20. The coefficient of variation for spKt/V as evaluated by Adimea® was 9.6 ± 3.4%, not significantly different from the 9.6 ± 8.6% as blood Kt/V taken at the same time. Conclusion: Online monitoring of dialysis dose by Adimea® improves and maintains dialysis adequacy. Implementing online monitoring by Adimea into daily practice moves the quality of dialysis patient care a significant step forward.

Chronic Kidney Disease: Socioeconomic Impact. Findings from a Two Center Study in Southwestern Nigeria

Introduction: Despite the rising prevalence of chronic kidney disease (CKD), access to adequate renal care is still not available to a very large part of the populace, essentially due to inadequate funds and this has further heightened the burden of the disease on patients and the general society. Measures are therefore needed to highlight this health challenge and proffer solutions. Methods: A comparative study in which consented 354 consented participants with CKD stage 3-5 gave history, were examined and had blood taken for serum biochemistry and hematocrit to access kidney function. Results: Two hundred and thirty six males and 118 females participated. The mean age of the participants was 52.11 ± 6.04 yrs. A greater percentage (44.6%) of participants had hypertension as cause of CKD and earned a monthly income less than the national minimum wage (47.7%). A greater proportion of participants had tertiary education (51.4%), were married (64.1%) and travelled less than 50 kilometers (67.5%) to access renal care. The health insured were more likely to be males (P=0.002), aged (P<0.001) have higher hematocrit (P=0.002), albumin (P=0.06), bicarbonate (P=0.04) and GFR (P=0.01).. The health insured had more frequent dialysis (P<0.001) and erythropoietin use (P<0.001. Forty percent of the health insured had renal transplant compared to 1.6% of the uninsured, P<0.001. The insured were more associated with IDHT as the uninsured were more associated with IDH. The health insured had a mean dialysis dose (Kt/V 1.34 ± 0.9) compared to 1.13 ± 0.5 for the uninsured, P<0.001. The dialysis dose was positively correlated with frequency of dialysis (P<0.001), and erythropoietin (P<0.001) but was negatively correlated with age (P=0.01) and serum creatinine (P=0.004). Predictors of dialysis dose were insurance status, frequency of dialysis, and erythropoietin, hematocrit, serum albumin and bicarbonate. Conclusion: Only 11.9% of the CKD cohorts had health insurance coverage and they were more likely to be males, aged, highly educated, with higher hematocrit, and albumin. The health insured had a mean dialysis dose of Kt/V 1.34±0.9 as against 1.13±0.5 for the uninsured. The uninsured had more metabolic acidosis, were younger and being the most active working population, their affectation only further worsens the burden associated with CKD. Key words: health insured, intradialysis hypotension, intradialysis hypertension, dialysis dose.

Combining Diffusion, Convection and Absorption: A Pilot Study of Polymethylmethacrylate versus Polysulfone Membranes in the Removal of P-Cresyl Sulfate by Postdilution On-Line Hemodiafiltration

Dialytic clearance of p-cresyl sulfate (pCS) and other protein-bound toxins is limited by diffusive and convective therapies, and only a few studies have examined how to improve their removal by adsorptive membranes. This study tested the hypothesis that high-flux polymethylmethacrylate (PMMA) dialysis membranes with adsorptive capacity increase pCS removal compared to polysulfone membranes, in a postdilution on-line hemodiafiltration (OL-HDF) session. Thirty-five stable hemodialysis patients randomly completed a single study of 4 h OL-HDF with PMMA (BG2.1U, Toray®, Tokyo, Japan) and polysulfone (TS2.1, Toray®) membranes. The primary endpoint was serum pCS reduction ratios (RRs) obtained with each dialyzer. Secondary outcomes included RRs of other solutes such as β2-microglobulin, the convective volume obtained after each dialysis session, and the dialysis dose estimated by ionic dialysance (Kt) and urea kinetics (Kt/V). The RRs for pCS were higher with the PMMA membrane than those obtained with polysulfone membrane (88.9% vs. 58.9%; p < 0.001), whereas the β2-microglobulin RRs (67.5% vs. 81.0%; p < 0.001), Kt (60.2 ± 8.7 vs. 65.5 ± 9.4 L; p = 0.01), Kt/V (1.9 ± 0.4 vs. 2.0 ± 0.5; p = 0.03), and the convection volume (18.8 ± 2.8 vs. 30.3 ± 7.8 L/session; p < 0.001) were significantly higher with polysulfone membrane. In conclusion, pCS removal by OL-HDF was superior with high-flux PMMA membranes, appearing to be a good dialysis strategy for improving dialytic clearance of pCS, enabling an acceptable clearance of β2-microglobulin and small solutes.

What Total Body Water Measurement Should Be Used for Prescribing the Dialysis Dose in Low-Flow Home Daily Dialysis?

<b><i>Introduction:</i></b> In low-flow home daily dialysis (HDD), the dialysis dose is evaluated from the total body water (TBW). TBW can be estimated by anthropometric methods or bioimpedance spectroscopy. <b><i>Methods:</i></b> A multicentric cross-sectional study of patients in HDD for &#x3e;3 months was conducted to assess the correlation and the difference between the anthropometric estimate of TBW (Watson-TBW) and the bioimpedance estimate (BIS-TBW) and to analyse the impact on the dialysate volume prescribed. <b><i>Results:</i></b> Forty patients from 10 centres were included. The median BIS-TBW and Watson-TBW were 35.1 (29.1–41.4 L) and 36.9 (32–42.4 L), respectively. The 2 methods had a good correlation (<i>r</i> = 0.87, <i>p</i> &#x3c; 0.05). However, Bland-Altman analysis showed an overestimation of TBW with Watson’s formula, with a bias of 2.77 L. For 4, 5, or 6 sessions per week, the use of Watson-TBW increases the dialysate prescription per week by 100 L, 45 L, or 10 L, respectively, over our entire cohort. There is no increase in the volume of dialysate prescribed with the 7 sessions per week schedule. <b><i>Conclusion:</i></b> BIS-TBW and Watson-TBW estimation have a good correlation; however, Watson’s equation overestimates TBW. This overestimation is negligible for a prescription frequency of &#x3e;5 sessions per week.

Patiromer in a Patient with Severe Hyperkalemia on Incremental Hemodialysis with 1 Session per Week: A Case Report and Literature Review

Hyperkalemia is common in patients with ESRD, undergoing hemodialysis (HD), and is associated with an increase in hospitalization and mortality. Residual kidney function in long-term dialysis patients is associated with lower morbidity and mortality in HD patients. Although the 2015 National Kidney Foundation-Kidney Disease Outcomes Quality Initiate (NKD-KDOQI) guidelines allow the reduction in the weekly HD dose for patients with a residual kidney urea clearance (Kur) &#x3e;3 mL/min/1.73 m², very few centers adjust the dialysis dose based on these criteria. In our center, the pattern of incremental hemodialysis (iHD) with once-a-week schedule (1 HD/W) has been an option for a group of patients showing very good results. This pattern is maintained as long as residual diuresis is &#x3e;1,000 mL/24 h, Kur is &#x3e;4 mL/min, and there is no presence of edema or volume overload, as well as no analytical parameters persistently outside the advisable range (serum phosphorus &#x3e;6 mg/dL or potassium [K⁺] &#x3e;6.5 mmol/L). Management of hyperkalemia in HD patients includes reduction of dietary intake, dosing of medications that contribute to hyperkalemia, and use of cation-exchange resins such as calcium or sodium polystyrene sulfonate. Two newer potassium binders, patiromer sorbitex calcium and sodium zirconium cyclosilicate, have been safely used for potassium imbalance treatment in patients with ESRD in HD with a conventional regimen of thrice weekly, but has not yet been studied in 1 HD/W schedules. We present the case of a 76-year-old woman in iHD (1 HD/W) treated with patiromer for severe HK and describe her clinical characteristics and outcomes. In addition, we review the corresponding literature. Based on these data, it can be anticipated that the use of patiromer may overcome the risk of hyperkalemia in patients with incident ESRD treated with less-frequent HD regimens.

A case of autosomal dominant polycystic kidney disease with amelioration of refractory cyst infections following prolonged hemodialysis time

Renal cyst infection is a frequent and serious problem in patients with autosomal dominant polycystic kidney disease (ADPKD). Cyst infection is often a refractory complication of treatment that leads to sepsis and death in patients with ADPKD. It was previously reported that a higher dose of dialysis demonstrated clearly better survival than shorten-time dialysis. The relationship between the frequency of cyst infection episodes in hemodialysis (HD) patients with ADPKD and the dialysis dose has not yet been fully elucidated. In this report, we describe a case of an HD patient with ADPKD that was provided elongation of HD time from 4-h twice weekly HD to 8-h thrice weekly nocturnal HD. As a result, the frequency of cyst infection episodes decreased from 10.0 to 1.5 days a month. Our findings suggest that prolonged HD time might contribute to amelioration of refractory cyst infections in patients with ADPKD.

Contact Activation Inhibitor, AB023, in Heparin-Free Hemodialysis: Results of a Randomized Phase 2 Clinical Trial

End-stage renal disease (ESRD) patients on chronic hemodialysis have repeated blood exposure to artificial surfaces that can trigger clot formation within the hemodialysis circuit. Dialyzer clotting can lead to anemia despite erythropoietin and iron supplementation. Unfractionated heparin prevents clotting during hemodialysis, but it is not tolerated by all patients. Although heparin-free dialysis is performed, intradialytic blood entrapment can be problematic. To address this issue, we performed a randomized, double-blind, phase 2 study comparing AB023, a unique antibody that binds factor (F) XI and blocks its activation by factor XIIa but not by thrombin, to placebo in 24 patients with ESRD undergoing heparin-free hemodialysis (www.clinicaltrials.gov #NCT03612856). Patients were randomized to receive a single pre-dialysis dose of AB023 (0.25 or 0.5 mg/kg) or placebo in a 2:1 ratio and safety and preliminary efficacy were compared to placebo and to observations made prior to dosing within each treatment arm. AB023 administration was not associated with impaired hemostasis or other drug-related adverse events. Occlusive events requiring hemodialysis circuit exchange were less frequent and levels of thrombin-antithrombin complexes and C-reactive protein were lower after AB023 administration compared with data collected prior to dosing. AB023 also reduced potassium and iron entrapment in the dialyzers, consistent with less blood accumulation within the dialyzers. We conclude that despite the small sample size, inhibition of contact activation-induced coagulation with AB023 was well tolerated and reduced clotting within the dialyzer.

MO1007RELATIONSHIP BETWEEN DIALYSIS ADEQUACY, ULTRAFILTRATION RATE AND SURVIVAL IN YOUNG HEMODIALYSIS (HD) PATIENTS HAVING INITIATED CHRONIC HD IN CHILDHOOD*

Background and Aims Hemodialysis (HD) adequacy is currently assessed based on weight-normalized small solute clearance (spKt/V), with same targets in both adult and pediatric patients on chronic thrice weekly hemodialysis, despite lack of pediatric studies to support this. It has been hypothesised that pediatric patients of small size may require higher spKt/V targets, due to higher ratio of body surface area (BSA) to body weight and/or greater post-dialysis urea rebound. Ultrafiltration rates (UFR) &gt;10-13 mL/kg/h, associated with increased mortality in adults, are furthermore routinely exceeded in pediatric patients with uncertain consequences. We aimed to characterize how different delivered HD adequacy metrics and UFR are associated with survival in a large cohort of patients who started HD in childhood. Method Retrospective analysis on a cohort of patients &lt;30y on chronic HD since childhood (&lt;19y), having received thrice-weekly HD 2004-2016 in outpatient DaVita dialysis centers. Mean delivered dialysis dose (spKt/V) and alternative measures of HD adequacy and fluid balance, including eKt/V, body-surface normalized Kt (Kt/BSA) and ultrafiltration rate (UFR), were investigated as predictors of survival in a Weibull regression model. Results A total of 1780 patients were included (age at initiation of HD: 0-12y: n=321, &gt;12-18y: n=1459), with median spKtV=1.55, eKt/V=1.31, Kt/BSA=31.2 L/m2 and UFR=10.6 mL/kg/h. Kt/BSA was a better predictor of survival than spKt/V or eKt/V (P&lt;0.001 versus P=0.002, respectively). UFR was associated with survival (P&lt;0.001), with increased mortality &lt;10/&gt;18 mL/kg/h. Associations remained significant after adjusting for age, ethnicity, and etiology of kidney disease. Conclusion We found that targeting Kt/BSA&gt;30 L/m2 in children and young adults on maintenance HD is associated with improved long-term outcomes, corresponding to spKt/V&gt;1.4 (&gt;12 years) and &gt;1.6 (&lt;12 years), respectively. Relatively high UFR of 10-18 ml/kg/h appears to be risk-free in this HD population.