Chronic Hemodialysis Patients Research Articles

PMMA dialyzers modulate both humoral and cell-mediate immune response to anti-COVID-19 vaccine (BNT162b2) in a cohort of chronic hemodialyzed patients

Patients on hemodialysis (HD) have a high risk of death from COVID-19. We evaluated the humoral and cell-mediated immune response to BNT162b2 (Pfizer-BioNTech) vaccine in HD patients, comparing HD with Poly-methyl-methacrylate (PMMA) and HD with Polysulphone (PS). Samples were collected before vaccination (T0) and 14-days after the 2ndvaccine (T2) in a TG (TG, n = 16-Foggia) and in a VG (CG, n = 36-Novara). Anti-SARS-CoV-2-Ig were titrated in the cohort 2-weeks after the 2nddose of vaccine. In the Testing-Group, serum neutralizing antibodies (NAb) were assayed and PBMCs isolated from patients were thawed, counted and stimulated with SARS-CoV-2 IGRA stimulation tube set. All patients had a positive ab-response, except in a case. PMMA-patients had higher levels of anti-SARS-CoV-2 IgG (p = 0.031); VG data confirmed these findings (p < 0.05). NAb evaluation: PMMA patients passed the positive cut-off value, while in PS group only only 1/8 patient did not respond. PMMA patients showed higher percentages of anti-SARS-CoV-2 S1/RBD-Ig after a complete vaccine schedule (p = 0.028). Interferon-gamma release: PMMA patients showed significantly higher release of IFNγ (p = 0.014). The full vaccination course provided sufficient protection against SARS-CoV-2 across the entire cohort, regardless of dialyzer type. After vaccination, PMMA patients show a better immune response, both humoral and cellular, at the end of the vaccination course than PS patients.

#1665 Mechanisms underlying long-term weight changes and their impact on all-cause mortality among chronic hemodialysis patients

Abstract Background and Aims Observational studies have demonstrated a significant association between long-term weight loss and weight gain and an increased risk of mortality among chronic hemodialysis patients. However, underlying mechanisms of these associations remain insufficiently explored. To address this knowledge gap, we conducted an in-depth analysis using a cohort of hemodialysis patients, benefiting from comprehensive baseline data, regular six-month evaluations, and an extended follow-up period. We employed advanced statistical techniques, including Lasso regression, to construct predictive models for long-term weight loss and gain. Furthermore, we conducted mediation analyses to elucidate whether weight change mediates the impact of major risk factors on all-cause mortality. Method This post-hoc analysis utilized data from participants in a previous randomized controlled trial conducted between 2006 and 2011, named as the Olmesartan clinical trial in Okinawan patients under the OKIDS (OCTOPUS) study. Subsequently, we tracked participants' mortality outcomes until July 2018. At the time of enrollment, we collected comprehensive baseline information, encompassing demographics, medical history, and laboratory data. Throughout the trial, participants' body weights were meticulously recorded every six months. Our analysis was restricted to patients who survived for at least two years post-enrollment, ensuring a minimum of five body weight measurements during the trial. Lasso regression was employed in training datasets (comprising 60% of participants) to identify crucial risk factors associated with long-term weight gain (&amp;gt;1 kg per year) or weight loss (&amp;lt;−1 kg per year) among chronic hemodialysis patients. These selected models were subsequently applied to paired validation datasets (comprising 40% of participants), and receiver operating characteristic (ROC) curves were used to calculate the area under the curve (AUC), aiding in the identification of key risk factors for long-term weight changes. Subsequently, we conducted mediation analyses to investigate whether weight change mediated the relationship between risk factors and all-cause mortality. Results Our analysis included 404 out of 461 OCTOPUS participants, with 60.9% being male, a mean age of 59.2 years (±11.7), and a mortality rate of 41.6%. The median follow-up period extended to 10.3 years. In the training datasets, Lasso models identified critical predictors for weight increase, including a history of diabetes, younger age, normal cardio-thoracic ratio (CTR) (&amp;lt;50% for males and &amp;lt;53% for females), and BMI &amp;lt;20. Conversely, predictors for weight decrease included BMI ≥20, serum sodium &amp;lt;135 mEq/L, serum albumin &amp;lt;3.5 g/dL, and older age. Weight increase demonstrated higher predictability (mean AUC of 0.59) compared to weight decrease (mean AUC of 0.55) in the validation datasets. Mediation analyses revealed that weight loss mediated 30% of the impact of older age (≥70 years old) on all-cause mortality (P = 0.068). Conclusion Our findings suggest that, among chronic hemodialysis patients, long-term weight increase is associated with a history of diabetes and younger age, while long-term weight loss is linked to BMI (≥20), hyponatremia, hypoalbuminemia, and older age. Notably, long-term weight loss appears to explain 30% of the increased risk of all-cause mortality associated with older age (≥70 years old).

#1228 MOTS-c improves CV and mortality risk prediction in chronic hemodialysis patients: a prospective, multicenter cohort study

Abstract Background and Aims Cardiovascular disease (CVD) is the leading cause of death in patients with end stage kidney disease (ESKD), especially in those undergoing chronic hemodialysis (HD), but correct risk prediction in this setting is often complicated. The mitochondrial open reading frame of 12S rRNA type-C (MOTS-s) is a peptide encoded by mitochondrial DNA, mainly expressed by cardiac and skeletal muscle tissues, which may prevent CVD thanks to its remarkable anti-oxidant capacities. From a clinical point of view, altered circulating MOTS-c levels predict worsen CV outcomes, particularly among diabetic individuals or post-AMI patients. Mitochondrial dysfunction is highly pervasive in HD patients. Starting from this background, we aimed at evaluating the clinical significance and predictive usefulness of measuring circulating MOTS-c in a multicenter cohort of chronic HD patients, beyond common cohort-related risk factors. Method We conducted a prospective, observational study on 94 chronic HD patients. The study endpoint was a composite of all-cause/CV mortality and non-fatal CV events. We identified the cohort-related predictors of the endpoint by logistic and Cox-regression analyses and built prognostic models based on such variables. Performance of such models was tested before and after the inclusion of MOTS-c. 31 healthy patients were employed as controls. MOTS-c was measured in serum using a commercially available ELISA kit. Results MOTS-c levels were more elevated in HD patients than in controls (36.7 [24.9-49.9] vs. 13.8 [10.4-28.7] ng/mL; p &amp;lt; 0.001; Fig. 1) and independently correlated with a history of ischemic heart disease (β = 0.213; p = 0.03), LVMi (β = 0.185; p = 0.05) and phosphate plasma concentration (β = −0.201; p = 0.05). Of note, MOTS-c levels were even more increased in the 53 individuals experiencing the endpoint during a median 26.5. months follow-up (p = 0.01; Fig. 2). MOTS-c predicted the endpoint at either multivariate logistic (OR 1.020; 95% CI 1.011-1.109; p = 0.03) or Cox-regression analyses (HR 1.004; 95% CI 1.000-1.025; p = 0.05) and the addition of this peptide to multivariate models including the other, cohort-related risk factors (age, LVMi, E/e’, diabetes, pulse pressure) remarkably improved the calibration, risk variability explanation (+3%), discrimination (ROC-AUC from 0.727 to 0.743; C-index from 0.658 to 0.700) and, particularly, the overall reclassification capacity (NRI 15.87%; p = 0.01). Conclusion Circulating MOTS-c balance is altered in chronic HD patients. In these individuals, MOTS-c may add significant information to improve CV and mortality risk prediction, on top of traditional and uremia-specific, cohort-related risk variables. Future investigations are needed to extend this preliminary observation in wider HD cohorts.

#1854 Prevalence of Fabry disease in chronic hemodialysis patients: a multicenter screening approach

Abstract Background and Aims Fabry disease (FD), an X-linked lysosomal storage disorder caused by alpha-galactosidase A (α-Gal A) deficiency, leads to significant morbidity and early mortality due to progressive organ failure. Given the availability of enzyme replacement therapy, early identification of FD is crucial for improving patient outcomes. Method A multicenter screening was conducted among chronic hemodialysis patients across six centers. We utilized a two-tiered diagnostic approach. Initially, α-Gal A activity was measured from dried blood spots on filter paper. Subsequently, those with reduced enzyme levels underwent GLA gene mutation analysis. Results Out of 428 patients, 255 (102 females and 153 males) were selected for testing, leading to the analysis of 239 patients. In the male cohort, the average α-Gal A activity was 21.84 ± 11.9 µmol/L/h, with 34 males below the cut-off value (&amp;lt;15.3 µmol/L/h) but with normal lyso-Gb3 levels and no mutations. Among females, α-Gal A levels were typically within the normal range. Notably, one female was found to have a heterozygous variant of uncertain significance in the GLA gene [p.(Asp313Tyr)] in exon 6, with normal α-Gal A and lyso-Gb3 levels. Screening of other family members was not possible, as they resided abroad although we recommended it. Conclusion Screening for AFD in high-risk groups, such as hemodialysis patients, is challenging yet essential. Implementing α-Gal A measurement as a standard procedure for newly registered hemodialysis patients could prospectively identify potential Fabry carriers, offering more excellent utility than our cross-sectional study. While identifying index patients at a late disease stage may not benefit the patients themselves, it is crucial for early detection of family members, potentially altering their disease course. This proactive approach, supported by national and international guidelines, could significantly impact the management and outcomes of AFD.

#2080 Prevalence and development of sarcopenia in chronic hemodialysis patients, a single center, prospective, observational study

Abstract Background and Aims Sarcopenia is a progressive muscle disease (muscle failure) associated with age and various factors including chronic kidney disease that increases the risk of falls, fractures, and mortality. We aimed to analyze the prevalence of sarcopenia and other related problems, such as nutrition or physical fitness, in a group of patients in a chronic dialysis program. Method In our dialysis center, we conducted a prospective observational study to monitor the prevalence and development of sarcopenia. We performed repeated SARC-F (simple five-item questionnaire), grip strength, bioimpedance analysis of body composition, short physical performance battery (SPPB), muscle sonography and MNA (Mini Nutritional Assessment) in chronic hemodialysis patients. Here we report the cross-sectional results of the prevalence of probable sarcopenia (according to the recommendations, enough to trigger assessment of causes and start intervention) defined by EWGSOP2 (the European Working Group on Sarcopenia in Older People), risk of malnutrition, physical fitness, and its development in 1 year follow up. Results The median age in our cohort was 64 years (IQR 16.5). We examined 58 patients (36 men and 22 women) who signed informed consent in the period from 1 October 2020 to 31 January 2023. The prevalence of probable sarcopenia was 20.7%. A higher prevalence was observed in women than in men (27.3% vs 16.7%, P = 0.505), in patients ≥65 years than in the &amp;lt;65 years (26.5% vs 8.3%, P = 0.102) and in the group of patients more than one year on dialysis compared to the group up to one year (27.8% vs 4.5%, P = 0.039). We observed reduced physical performance (SPPB test) in 20 subjects (34.5%) and risk of malnutrition according to MNA in 33 subjects (56.9%). Seven of 29 evaluated patients (24.1%) had a worsening of physical performance (SPPB) after one year. Ten out of 29 patients (34.5%) had worsened MNA scores; the prevalence of malnutrition risk in this group remained the same (51.7%). The development of other parameters did not lead to significant conclusions, given the heterogeneity of characteristics and the relatively small number of subjects. Conclusion Sarcopenia is a serious and potentially impactful problem. The prevalence of probable sarcopenia in our cohort was 20.7% and was higher, although not statistically significant, in women, in patients ≥65 years of age and in patients more than one year on dialysis.

#2923 Intracardiac vascular access as a last resort for hemodialysis in patients with exhausted traditional vascular access: a case report

Abstract Introduction The dysfunction of vascular access (VA) constitutes one of the main problems faced by nephrologists and patients in chronic hemodialysis (HD). This challenge becomes particularly worrying in patients who have depleted their upper extremity venous resources and have no longer arteriovenous fistula available, requiring the placement of a central venous catheters. It leads to an increase in morbidity and mortality and a higher of infections, thrombosis and exhaustion of access points. In such cases, alternatives to conventional VA are limited, with intracardiac access being an emerging option, albeit with very limited documented experience. Case Report We describe the case of a 68-year-old male with a history of hypertension, nasopharyngeal carcinoma in 2012 treated with chemotherapy and radiotherapy. In 2018 he was diagnosed with low-grade urothelial bladder carcinoma (PT1G1) that infiltrated the subepithelial corion while sparing the muscular layer. He also had severe hydronephrosis with impaired renal function, requiring radical cystoprostatectomy with Bricker bladder reconstruction and subsequent bilateral nephrostomy due to persistent dilatation and progressive deterioration of renal function. He began chronic HD in June 2020 through a left femoral catheter due to the inability to access the upper thoracic vascular tree due to stenosing fibrosis from previous radiotherapy. He was placed on the waiting list for a kidney transplant (KT) in the right iliac fossa but experienced multiple catheter dysfunction episodes, requiring the placement of a right femoral venous catheter to continue with his HD sessions. Additionally, peritoneal dialysis was not considered due to previous urological surgery. Considering the limitation of VA and the possibility of KT as its best alternative, we opted for the insertion of a tunnelled intracardiac catheter at the right atrium. This procedure was conducted by the Cardiac Surgery Department on 03/12/2021 through a median sternotomy in the 4th intercostal space. A permanent hemodialysis catheter was inserted in the right atrium through the 3rd intercostal space and fixed with a purse-string suture. It was then tunnelled under the breast to the 2nd intercostal space through a counter-incision. The cuff was appropriately placed in the subcutaneous tissue (Figs 1 and 2). The intervention proceeded without any complication and the catheter exhibited normal functionality. After that, the patient received anticoagulation with enoxaparin the days between dialysis sessions. Consequently, the right femoral catheter was safely removed. Two weeks later, the patient successfully received a KT from a deceased donor. He was discharged on the day 11st post-KT with any complication and maintains a good renal function after 2 years of follow-up with a serum creatinine 1.7 mg/dL (eGFR: 39 ml/min). The intracardiac catheter was removed one month later through a mini-thoracotomy. Conclusions Intracardiac VA is an unusual and high-risk resource that seems an alternative in patients with exhausted VA with no alternative emergency renal replacement therapy, so it should be considered as the last resort. In the case of our patient, the implantation of this catheter allowed for the continuation of dialysis and access to KT.

#2812 Continuous blood pressure monitoring with a finger cuff is unreliable in chronic hemodialysis patients

Abstract Background and Aims Intradialytic hypotension (IDH) is the most common complication of hemodialysis (HD), which is often related to ultrafiltration. Due to the high prevalence of cardiovascular disease (CVD), compensatory mechanisms often fail. In clinical practice, BP is measured 2x/hour, while additional readings are only performed when symptoms arise. However, since IDH defined by a nadir systolic BP (SBP)&amp;lt;90 mmHg or &amp;lt;100 mmHg (depending on pre-dialysis SBP), regardless of symptoms, is most strongly associated with mortality, current BP measurement frequency may severely underestimate the true incidence of IDH. Continuous BP-monitoring may offer a solution to this issue. The Clearsight device (CSD) is a non-invasive continuous BP-monitoring system that measures arterial pressure and waveforms through a finger cuff by photoplethysmography. Yet, a compromised peripheral circulation may hamper its reliability in HD patients. This study aims to assess the agreement between intradialytic CSD-monitoring and standard oscillometric brachial arterial pressure (oBAP) assessment. Methods 40 Chronic HD patients were cross-over randomized to 4 modalities, each for 2 weeks: [standard HD (S-HD), cool HD (C-HD), low volume hemodiafiltration (LV-HDF) and high-volume HDF (HV-HDF)]. During one session of each second week, BP and heart rate (HR) were continuously recorded with the CSD (BMEYE/Edwards Lifesciences) and every 15 minutes with a brachial arterial cuff (contralateral of the fistula or graft, if applicable). Simultaneous measurements of SBP, diastolic BP (DBP) and HR were compared with descriptive statistics (mean difference [bias, BAP minus CSD], standard deviation (SD) and range) and Bland-Altman analysis. Bias was defined as the mean difference between oBAP and CSD, and 95% limits of agreement (LA) as the mean difference ±1.96 SD. Post-hoc, patients were stratified into tertiles of unexplained missing CSD-readings, to explore whether specific patient characteristics explain failed readings. Results 75% of patients was male, with a mean age 69.7 (±13.5 years) and median dialysis vintage 3.0 years (IQR 1.0-5.8). Diabetes mellitus and CVD were present in 48% and 73%, resp. Of the 2720 paired BP-measurements, 42% CSD and 6% of oBAP-readings were missing, leaving 36% of absent CSD-readings unexplained. Bland-Altman analysis, comparing oBAP and CSD-measurements, revealed a mean bias ± LA of 13.3 ± 44.5 mmHg for SBP, a mean bias ± LA of 13.3 ± 25.5 for DBP, and a mean bias ± LA of −0.03 ± 22.9 for HR. Surprisingly, the group with a high (&amp;gt;38%) proportion of unexplained missing CSD-values was significantly younger compared to the low (&amp;lt;21%) and intermediate group (21-38%) (p = 0.015), whereas no significant differences were observed with respect to dialysis vintage, diabetes mellitus or CVD. Conclusions 1) Compared to the oBAP method, finger cuff-monitoring shows poor precision and accuracy in BP-measurements, but good accuracy and poor precision in HR-readings; 2) 1/3 of readings failed for unknown reasons. Thus, CSD-monitoring is unsuitable for intradialytic hemodynamic monitoring in chronic HD patients.

#1024 Lung ultrasound in 28 versus 8 places and volume status in chronic hemodialysis patients

Abstract Background and Aims Overhydration is considered a significant risk factor for cardiovascular and all-cause mortality in end-stage kidney disease patients. Measurement of total and extracellular water with bioelectrical impedance analysis (BIA), inferior vena cava diameter (IVCd) measurement, and circulating pro-B-type natriuretic peptide (proBNP) levels have previously been tested as possible indicators of volume status in hemodialysis (HD) patients, with BIA showing the most potential. Recently, it has been shown that lung ultrasound (LUS)-guided volume depletion is an effective strategy for relieving lung congestion in chronic HD patients. The aim of our study was to determine whether performing LUS on only 8 places was comparable to the regular 28 places. Method LUS was performed on 29 randomly selected patients before their regular HD procedure in 28 regular places and correlated with 8 places (4 on each side). In addition, BIA with a body composition monitor (BCM) was performed, IVCd was measured using ultrasound and serum NT-proBNP value was determined. Statistical analysis was performed using a commercially available SPSS® for Windows® (version 29.0; Chicago, IL, USA). Spearman's non-parametric test was used to determine a correlation between variables. P-values less than 0.05 were considered statistically significant. Results We included 29 chronic HD patients, 15 male (51.7 %), with a mean age of 66.3 ± 12.5 years and a median dialysis vintage of 53.0 (95% CI (40.9, 100.6)) months. Most patients (96.6 %) had a functional arteriovenous fistula, whereas only one patient (3.4 %) was dialysed using a Hickman catheter. A very strong, directly proportional correlation was found between performing LUS in 28 and 8 places (ρ=0.909; p&amp;lt;0.001). A significant moderate correlation was also found between both LUS in 28 and 8 places and systolic blood pressure (ρ=0.503; p=0.005 and ρ=0.467; p=0.011, respectively) (Table 1). Neither of the LUS methods statistically correlated with other tested volume markers – overhydration, intracellular and extracellular volume measured with BIA, IVCd in inspiration and expiration and IVC index, or serum NT-proBNP levels. Conclusion In our study, we found a very strong, positive, and significant correlation between performing LUS in 28 regular places and 8 places. Both also moderately correlated with systolic blood pressure. However, we did not find a statistically significant correlation between LUS and other tested volume markers.

#2887 Interdialytic weight gain and low dialysate sodium concentration in patients on chronic hemodialysis: a systematic review and meta-analysis

Abstract Background and Aims In many patients on chronic hemodialysis, interdialytic weight gain (IDWG) is greater than 4.0%-4.5% of dry weight, the value recommended by the international guidelines. High IDWG is a condition associated with risk of all-cause mortality and hospitalization and it depends on elevate intake of fluids and/or foods. More specifically, high intake of water is secondary to the disturbing and constant presence of thirst in such patients, so the limitation of the IDWG is a challenge both for the patients and the physicians. Low dialysate sodium levels can significantly reduce thirst as well as the water intake in the interdialytic period because they can increase the removal of sodium during the dialytic session, and this leads to a reduced content of sodium in the body. The present systematic review and meta-analysis aims at evaluating the efficacy of low dialysate sodium concentration on interdialytic weight gain (IDWG) in chronic hemodialysis patients. Method Studies were eligible for inclusion if they were English language papers published in a peer-reviewed journal and met the following inclusion criteria: 1) Primary research studies in adult patients (over 18 years of age), 2) Included patients with end-stage renal disease on chronic hemodialysis since at least 6 months; 3) Compared standard (138-140 mmol/l) or high (&amp;gt;140 mmol/l) dialysate sodium concentration with low (&amp;lt;138 mmol/l) dialysate sodium concentration; 4) Included one outcome of interest: interdialytic weight gain. We excluded studies on pediatric patients, pre-dialysis CKD patients, acute kidney injury patients, ESRD patients with other renal replacement therapy modalities such as peritoneal dialysis and transplant. Medline, PubMed, Web of Science, and the Cochrane Library were searched for studies comparing low or high dialysate sodium concentration. Outcome of interest was IDWG. The quality of reporting for each study was performed using the Quality Assessment Tool of Controlled Intervention Studies of the National Institutes of Health. The quality of reporting of each cross-over study was performed using the Revised Cochrane Risk of Bias (RoB) tool for cross-over trials as proposed by Ding et al. Results Nineteen studies (710 patients) were included in the analysis: 15 were cross-over and 4 parallel randomized controlled studies. In cross-over studies, pooled analysis revealed that dialysate sodium concentration reduced IDWG with a pooled MD of −0.40 kg (95% CI -0.50 to −0.30; P &amp;lt; 0.00001). The systematic review of four parallel, randomized, studies revealed that the use of a low dialysate sodium concentration was associated with a significant reduction of the IDWG in two studies, sustained and almost significant (P=0.05) reduction in one study, and not significant reduction in one study. In most studies, the frequency of intradialytic hypotensive events did not differ significantly between low and high sodium dialysate hemodialysis. The GRADE methodology was used to assess the quality of the body of retrieved evidence and studies risk of bias, inconsistency and imprecision were estimated as low. Conclusion Low dialysate sodium concentration reduces the IDWG in patients on chronic hemodialysis.

#1277 Comparing advanced glycation end products removal in super high-flux hemodialysis versus high-volume hemodiafiltration: a randomized, crossover study

Abstract Background and Aims Expanded hemodialysis using super high-flux membrane, is a promising therapy for effectively clearing middle molecule uremic toxins. However, its impact on advanced glycation end products (AGEs), which is related to an increase in cardiovascular mortality [1], remains inconclusive. Previous studies demonstrated that AGEs increased over time in patients treated with high-flux hemodialysis (HD) [2, 3] while remaining stabilized in online hemodiafiltration (ol-HDF) [3]. This study aims to compare the longitudinal tissue AGEs measured by skin autofluorescence (SAF) between super high-flux hemodialysis (SHF-HD) and high-volume post-dilution ol-HDF. Method In this open-label prospective cross-over 24-week trial, twenty-two prevalent HD patients were randomly assigned to undergone two sequences of 24-week treatment periods: SHF-HD followed by high-volume postdilution ol-HDF or vice versa, with a 4-week wash-out period with high-flux HD between. SAF was measured at baseline and 24 weeks. Midweek pre-HD measurements of beta-2 microglobulin (B2M), serum albumin, normalized protein catabolic rate (NPCR) and Kt/V were obtained every 8 weeks. The amount of dialysate albumin was collected by continuous sampling of spent dialysate method and determined by immunoturbidimetric assay Results Seventeen out of twenty-two patients completed the study. At baseline, SAF levels (3.88 ± 0.14 vs 3.99 ± 0.14 AU, p = 0.463) and pre-HD B2M (22.66 ± 1.41 vs 21.09 ± 1.41 mg/L, p = 0.228) were similar between the SHF-HD and ol-HDF groups. After 24 weeks, SAF levels showed no significant change in SHF-HD (from 3.88 ± 0.14 to 3.91 ± 0.14 AU, p = 0.846) and ol-HDF (from 3.99 ± 0.14 to 3.95 ± 0.14 AU, p = 0.796), with a mean difference of change 0.06 (95% CI −0.34, 0.47, p = 0.75). Similarly, mid-week pre-HD serum B2M at 24 weeks exhibited no significant change in the SHF-HD group (22.66 ± 1.41 to 22.18 ± 1.47 mg/L, p = 0.722) and the ol-HDF group (21.09 ± 1.41 to 21.83 ± 1.45 mg/L, p = 0.577), with a mean difference of change −1.22 (95% CI −4.94, 2.49, p = 0.519). The spKt/V urea did not exhibit any notable differences. Furthermore, pre-HD levels of all small uremic toxins after the 24-week periods did not differ between both groups. Nutritional status measured by serum albumin and NPCR were comparable despite higher dialysate albumin loss in postdilution ol-HDF group (0.82 ± 0.04 vs 1.92 ± 0.12 g, p &amp;lt; 0.001 in SHF-HD and ol-HDF, respectively) Conclusion After 24 weeks of treatment, SHF-HD demonstrated levels of AGEs, pre-HD serum B2M, and serum albumin comparable to high-volume ol-HDF. If high-volume postdilution ol-HDF is not feasible, SHF-HD may serve as a valuable alternative treatment for stabilizing AGEs in chronic hemodialysis patients.

#3034 Therapeutic compliance: another challenge for patients on chronic hemodialysis

Abstract Background and Aims Therapeutic compliance corresponds to the degree of concordance between the patient's behavior and the recommendations of his doctor. Non-adherence to treatment predispose to high risk of mortality and increases health costs. The objective of our study was to assess the level of compliance in chronic hemodialysis patients and to identify the predictive factors of poor compliance. Method A cross-sectional study was conducted in the hemodialysis center at Taher Sfar Hospital in Mahdia. Medication adherence was assessed using a “compliance assessment test” quiz comprising six questions to which the patient must answer yes or no. Results Sixty-one patients were enrolled. The mean age was 50 ± 13 years (26 - 79 years) with a sex ratio M/F of 1.27. The patients have diabetes mellitus and hypertension in 35% and 68% of cases. They were dialyzed for a long duration (37 ± 15 months) that reaches a maximum of 280 months. The main initial nephropathies were diabetic nephropathy (35.5%) and chronic interstitial nephropathy (23.5%). Adherence was poor in 16.9 % of patients, average in 55.9% of patients while 27.1% were good adherents. Polymedication and missing of treatment were the leading causes of non-adherence. In univariate analyses, the socio-economic level affected significantly the compliance in elderly group as well as high comorbidity score (Charlson) (p&amp;lt;0.04) and diabetes status (p=0.04). No significant difference was found between elderly and young group in term of compliance to treatment. Conclusion Compliance is a dynamic behavior that is difficult to predict and requires constant monitoring. In our hemodialysis center it turned out to be good; we must insist on the therapeutic education of patients and minimize the list to the necessary.

#2973 COVID-19 increased hemodialysis patients’ mortality, relation with inflammation and telomere attrition

Abstract Background and Aims An increased risk of mortality and hospitalization has been consistently demonstrated in patients with CKD who are additionally affected by corona virus disease 19 (COVID-19). In this study, we tried to identify predictive factors of mortality and hospitalizations, especially the ratio of neutrophils to lymphocytes (NLR), lactate dehydrogenase (LDH), c-reactive protein (CRP), disease status of COVID-19, telomere length in peripheral blood cells (TL) and 2-year risk score. Method A total of 130 chronic hemodialysis patients, were enrolled in the present study and followed up for 18 months. Routine laboratory parameters including LDH, were determined by standard automated methods, redox status parameters SOD and O2. - Using spectrophotometric methods.TL was determined using the modified Cawthon method and was calculated as the T/S ratio. Kaplan-Meier analysis was used to test survival predictors. Results Patients in deceased group (30%) were significantly older (p &amp;lt;0.001), with higher body mass index (BMI), (p &amp;lt; 0.01) than survived patients. Also, patients in the deceased group had higher levels of LDH, NLR index, CRP compared to survivors. Lower lymphocytes and shortened TL were characteristic of these patient groups, but the deceased group had the lowest lymphocytes (p &amp;lt; 0.005) and telomeres (p&amp;lt;0.002), and had the highest NLR (0.004). The difference in 2-years risk score also was significant (p &amp;lt; 0.001), with higher scores in the deceased group. Kaplan-Meier survival analysis showed six parameters were significant predictors in the following order of significance: COVID-19 status, 2-years risk score, NLR, TL, CRP, LDH. Using binary logistic regression analysis Summary risk score, a combination of these six parameters revealed as the best predictor of patients’ survival in this group of parameters (Log rank=25.4, P &amp;lt; 0.001). Conclusion Independent predictors of mortality in chronic haemodialysis patients are higher NLR, CRP, LDH, Lower lymphocytes and shortened TL, and COVID -19 made the situation even worse by significantly arising these patients’ mortality rate.

#704 Albumin, inflammation and nutrition in hemodialisis patients in Colombia: a cohort study

Abstract Background and Aims Hypoalbuminemia is a well-identified risk factor for mortality in chronic hemodialysis patients. As a negative acute phase reactant, albumin levels could be associated with several factors that affect the patient on hemodialysis (HD), such as alterations in the rate of hepatic synthesis, an increase in the rate of catabolism, or an increase in losses due to the dialysis process. The objective of the present study is to analyze serum albumin values in repeated measurements over time in two cohorts, one with expanded HD (HDx) enabled by the medium cut-off membrane (MCO) Theranova and the other with high flux (HF) HD and estimate the relationship with other relevant variables. Method Cohort study, one with HDx enabled by Theranova® and the other with HF HD, adult prevalent HD patients (&amp;gt; 90 days) at Baxter Renal Care Services Colombia starting between September 1, 2017, and November 30, 2017, with follow-up for up to 48 months. Sociodemographic and clinical characteristics were summarized descriptively, and a mixed linear model with repeated measures was performed to evaluate the association between dialysis membrane and albumin levels, controlling for confounding variables. Results We evaluated 1092 patients (62% male): 533 in HF-HD vs. 559 in HDx (Table 1); the median age was 61 years, 42% had a history of diabetes, and 19% had cardiovascular disease. We found no differences in albumin levels over time when comparing Theranova versus HF HD patients, p-value = 0.789 (see Fig. 1). No association between serum albumin levels and the Theranova dialyzer was found with the linear mixed model with repeated measures when controlling for confounding variables, p-value= 0.198. On the other hand, we found that serum albumin was associated with inflammatory and nutritional variables such as C reactive protein, Ratio platelets/lymphocytes, and Protein Energy Wasting (PEW) (Table 2). Conclusion Variables including nutritional status and inflammation, age, and hospitalization events are associated with serum albumin levels varying over time. Variation in serum albumin levels over time are not associated with type of dialyzer (Theranova® vs HF).

#885 Combination of medium cut-off dialyzer membrane and diet modification to reduce serum concentrations of p-cresyl sulfate and indoxyl sulfate

Abstract Background and Aims Online hemodiafiltration (ol-HDF) may be considered currently as the best choice for chronic hemodialysis (HD) treatment, but medium cut-off (MCO) membranes may provide similar efficiency for larger and protein-bound toxin removal. P-cresyl sulfate (PCS) and indoxyl-sulfate (IS) concentration depends mainly on residual renal function and diet. Increased dietary fiber intake and short-chain fatty acid (SCFA) supplementation were associated with decreased production of PCS and IS. The aim of this study was to pragmatically combine MCO use with diet modification in an attempt to reduce serum concentration of PCS and IS and compare this strategy to online HDF use. Method We report preliminary results from a subset of a study sample with 42 chronic prevalent HD patients in a prospective randomized controlled interventional study. Two weeks after standard bicarbonate HD (BHD), patients were randomized to hemodialysis with MCO membrane (EXP group) or ol-HDF with a standard "high-flux" (HF) dialyzer membrane (CON group). After 4 weeks, both groups were supplemented by a change in the diet with increase of the daily intake of dietary fiber to 30g and addition of a SCFA propionate in the dose of 1g daily for 8 weeks. Two main outcomes were serum concentrations of PCS and IS. Measurements were taken at baseline (after 2 week wash-in period), after 4 weeks of the first intervention phase (MCO vs. ol-HDF; T1), after 8 weeks of the second intervention phase (fiber and SCFA supplementation; T2) and finally, after 4 weeks of wash-out period with BHD (T3). Results From 42 participants, 38 completed the study (63.2% men, 66.4±10.9 years, Charlson comorbidity index 5.7±2.3). In the CON group, serum concentrations of PCS (in μg/ml) were 36.8±19.6 (baseline), 36.9±20.8 (T1), 32.4±17.4 (T2) and 38.6±22.1 (T3). Serum concentrations of IS (in μg/ml) were 31.8±13.0 (baseline), 32.9±14.7 (T1), 29.5±9.1 (T2) and 35.5±16.8 (T3). In the EXP group, serum concentrations of PCS were 33.5± 16.6 (baseline), 35.9±17.8 (T1), 34.0±16.1 (T2) and 37.4±21.5 (T3). Serum concentrations for IS were 39.6±12.6 (baseline), 37.3±12.9 (T1), 42.3±13.5 (T2) and 41.0±12.8 (T3). Repeated measures ANOVA revealed no significant time*group interaction for PCS (F(1,33)=0.479, p=0.698, ŋ2=0.014) and IS (F(1,33)=2.392, p=0.073, ŋ2=0.068). There was a significant within-group increase in serum IS concentration between T2 and T3 in CON group (p=0.042). There was a trend towards a decrease in PCS concentration between T1 and T2 and increase between T2 and T3 in CON group. Conclusion The results of the study suggest both hemodialysis methods are equivalent in eliminating PCS and IS. Additional fiber and SCFA propionate supplementation did not decrease serum PCS and IS concentrations significantly, although there was a trend towards lower serums concentration of PCS after diet modification in CON group.

#2434 Literature review on the burden of herpes zoster in patients with kidney disease—a need for earlier prevention

Abstract Background and Aims Kidney disease (KD), including end stage renal disease (ESRD), is a global health problem. Both are associated with impaired immune systems, which can lead to infections. Complications such as cardiovascular disease and various infections are leading causes of morbidity and mortality in KD patients. Notably, patients with KD have an increased risk of herpes zoster (HZ). While the link between ESRD and renal transplant with increased HZ risk is understood, knowledge gaps regarding the burden of HZ across the KD spectrum still exist. This review aims to describe the risk and impact of HZ across the KD spectrum in order to guide preventive care strategies for patients with renal diseases. Method A structured literature review was conducted in PubMed using a combination of keywords and Medical Subject Heading (MeSH) terms to identify studies related to HZ risk in adult KD patients aged ≥18 years published in the English language between 01/11/2003–31/10/2023. Data extracted from published studies included the burden of HZ infection in patients with KD (risk of HZ and related complications), impact of HZ on underlying KD, and the efficacy/effectiveness of HZ vaccines among patients with KD. Results A total of 47 studies were identified (Randomized controlled trials [RCT] = 2; observational studies = 45) in this review (Fig. 1). Included studies presented evidence from regions in Europe (n = 18), Asia (n = 17), North America (n = 7), South America (n = 1), multinational (n = 2) and Australia (n = 1); country not reported in one study. Evidence from observational studies (n = 37) reported a high risk of HZ infection and related complications, such as disseminated HZ, and recurrent HZ across the KD spectrum, including chronic KD, polycystic KD, hemodialysis, peritoneal dialysis and kidney transplant patients. Infection with HZ was reported to accelerate KD progression and increased the risk of ESRD and cardiovascular events. In general, for ESRD patients with an inpatient HZ diagnosis, mortality increased with age, followed by malnutrition and bacteremia/septicemia. Studies reporting vaccine efficacy (n = 2) and effectiveness results (n = 8) suggest that HZ vaccination was associated with a reduced risk of HZ when compared to unvaccinated individuals. Furthermore, the recombinant zoster vaccine (RZV) was found to be immunogenic in kidney transplant recipients, with immunogenicity persisting through 12 months post-vaccination. An RCT post-hoc analysis showed high vaccine efficacy in patients aged ≥50 years with medical conditions at enrollment, including KD, which was consistent with the overall population. A favorable benefit-risk profile was reported in randomized and observational studies. Studies evaluating the effectiveness of the zoster live-attenuated vaccine (ZVL) found a lower risk of HZ in patients with ESRD immunized against HZ compared to unvaccinated individuals. In many countries, vaccination guidelines specifically recommended immunization of people with KD to protect against HZ. However, ZVL is contraindicated for immunocompromised (e.g. kidney transplant) patients. Conclusion Findings indicate that HZ has a significant HZ burden across the KD spectrum, which may negatively impact renal disease progression. With effective vaccines offering durable protection against HZ and its complications, the immunization of renal patients at earlier stages could enhance healthcare management and patient outcomes.

#529 Educational level and mortality in patients receiving chronic hemodialysis in Lazio Region—Italy

Abstract Background and Aims In 2010, 2.6 million people received Kidney Replacement Treatment (KRT) worldwide. Hemodialysis (HD) is the most commonly used KRT. HD patients have a consistent risk of death. The impact of Educational Level (Edl) on the mortality in HD patients is unclear. This study aims to analyse the association between the Edls and mortality in incident chronic HD patients using the Lazio Regional Dialysis and Transplant Registry. Method A cohort of incident HD patients between 2008 and 2022 was selected. Patients under 18 years old and with a follow-up period shorter than 91 days were excluded. All patients were characterized by sociodemographic and clinical characteristics at the incident date and were followed from the incident date until the earliest of the following dates: death, transplantation, renal function recovery or end of the study (one or three years after initiation). One-year and three-year Crude Mortality Rates*100 Person Years (CMR*100PY) overall and by Edal (low: up to primary school, medium: secondary school, high: university degree and more) were calculated. Cumulative survival estimates at one year and three years since starting HD, were presented as Kaplan-Meier curves by EdL and compared using the log-rank test. Crude and adjusted Hazard Ratios (HR) and respective 95% Confidence Intervals (95% CI) of the association between EdL and one and three-year mortality were calculated using univariate and multivariate Cox regression models (reference category: low EdL). Sociodemographic and clinical characteristics were considered potential confounders or effect modifiers in the adjusted Cox regression models. Results The cohort counted 9,776; 33.5% had a low EdL, 30.7% had a medium, and 35.8% had a high EdL. The mean age decreased with increasing EdL (73 and 65 in low and high EdL, respectively) as the proportion of females (43.0% and 26.0% in low and high EdL, respectively). During the first year of HD, 1,683 deaths occurred, and 3,827 occurred within three years. One-year CMR*100PY were 24.1 (95% CI 22.4-26.0) in low EdL, 17.4 (95% CI: 15.9-19.0) in medium EdL and 15.0 (95% CI: 13.8-16.4) in high ED. The corresponding three-year CMR were 22.7 (95% CI 21.6-23.8), 17.4 (95% CI 16.4-18.4) and 15.1 (95% CI 14.2-16.0). One-year survivals estimates were 78.0% in low EdL, 83.8% in medium and 85.8% in high EdL (log-rank test: p-value &amp;lt; 0.001). The three-years survival estimates were 51.0% in low EdL, 59.3% in medium EdL and 63.7% in high EdL (log-rank test: p-value &amp;lt; 0.001). In one-year mortality the crude HRs were 0.72 (95% CI: 0.64–0.81) and 0.62 (95% CI: 0.55–0.70) of medium and high EdL vs. low EdL respectively; the corresponding adjusted HRs were 0.93 (95% CI: 0.83–1.06) and 0.92 (95% CI: 0.81–1.04) (Fig. 1). Similar results were obtained for three-year mortality: crude HRs were 0.77 (95% CI: 0.71–0.83) and 0.66 (95% CI: 0.62–0.72); adjusted HRs were 0.99 (95% CI: 0.92–1.08) and 0.97 (95% CI: 0.89–1.06), respectively (Fig. 2).). Conclusion Based on the present study, high educational level does not appear to be associated with lower mortality risk at either one-year or three-years. Hemodialysis patients are constantly monitored by National Health Service; this probably cancels the effect of low educational level on mortality. Although EdL is a strong indicator of socioeconomic position, it does not capture all dimensions of disadvantage. The mechanisms that underline the poor prognosis in Haemodialysis patients are complex and further investigations are needed.

#1813 Safety and efficacy of reducing hemodialysis fluid flow rate—contribution to planetary health

Abstract Background and Aims Historically, increasing dialysate flow rates (Qd) have been recommended to improve hemodialysis (HD) efficiency. For decades, Qd has routinely been set to a fixed rate of 500 ml/min. A standard HD treatment uses on average around 500 L of water [1], resulting in a consumption of 78 000 L per patient and year with an additional estimated 10 000 L for post-dilution hemodiafiltration. This corresponds to the annual water consumption of 1.5 persons in developed countries and considerably more in developing countries. We investigated the effect of reducing dialysate flow rates on HD safety and efficacy. Method This is a prospective single-center non-blinded observational study. We investigated the effect of a 1:1 adjustment of online Qd to blood flow rate by adjusting autoflow (AF) settings of the dialysis monitor to a calculation factor of 1.0 with a lower Qd limit of 350 ml/min (AF 1.0 mode). We examined the effect on dialysis efficacy, metabolic markers, and anemia in routine biochemical analyses, and calculated energy, water, and waste savings in 116 stable chronic HD patients. Data were compared with previous turnover in energy, waste, and water, as well as with clinical results prior to the mentioned modifications. Results After 12 months of HD treatment with AF 1.0 mode we observed reductions of 10% in electricity consumption, 19% in raw water consumption, and 24% in dialysate concentrate consumption. Conversely, we did not observe deteriorations in treatment quality or dialysis dose (Table 1), nor phosphate or hemoglobin. Conclusion Long-term HD treatment with reduced dialysate fluid flow rates led to substantially improved water and carbon footprints with potential effects on planetary health and economic savings, while dialysis quality remained unchanged.

#2703 Venous chambers vary in the reduction capacity of air microbubbles: a randomized study of chronic haemodialysis patients

Abstract Background and Aims The extracorporeal circuit (ECC) enables haemodialysis (HD) of patients. When the blood passes the ECC air contamination occurs, and consequently microbubbles (MBs) enter into the patient. MBs are verified at autopsy of HD patients and are covered by clots manifested as microemboli that are deposited within the lung, heart and brain tissue. A venous chamber is inserted in the ECC to reduce air contamination. However, venous chambers in clinical use have limited capacity in eliminating MBs from entering the return bloodline. In an in vitro study, the Emboless® chamber showed better results in comparison to models commonly used clinically (the best of the clinical models was the Fresenius 5008). Our aim was to determine if the Emboless® venous chamber differed in its capacity to limit MB exposure compared to the Fresenius 5008 (F5008) during HD and hemodiafiltration (HDF). Method Twenty chronic HD patients were included in a cross-over randomized study to compare the Emboless® to the F5008 venous chamber during HD. Each patient underwent a total of four dialyses divided into two paired series. This resulted in 80 studied dialyses, of which 32 included HDF. Dialyzers, blood-pump speed, HD or HDF, and ultrafiltration was the same between the pairs. MBs (20-500 µm, merged in intervals of 5 µm) were measured with an ultrasound device adjusted for HD (BCC200, GAMPT) at the ‘inlet’ and ‘outlet’ of the venous chamber. Measurements of MBs were done in the HD mode during the first 30 minutes, and if HDF was prescribed the measurement proceeded for another 30 minutes after the switch to the HDF mode (time was extended if fewer than 1000 MBs were detected at the inlet). The percentage of change in the ‘outlet’ versus ‘inlet’ counts was compared (paired Wilcoxon test). A total reduction was equal to −100%, while an increase (+) of MBs (worsening) was expressed as an unlimited percentage. If a diameter of an MB was without counts, it was not included in the analysis. Results For patients during HD, the median change of MBs in the outlet versus the inlet bloodline was −39% with the F5008 (n = 3807) and −76% with the Emboless® (n = 3805) venous chambers (p &amp;lt; 0.001, Fig. 1). For patients during HDF, the median change of MBs in the outlet versus the inlet bloodline was −28% with the F5008 (n = 1549) and −70% with the Emboless® (n = 1517) venous chambers (p &amp;lt; 0.001, Fig. 2). Conclusion Fewer MBs and subsequently fewer microemboli entered the patient using the Emboless® compared to the Fresenius 5008 venous chamber during HD, as well as during HDF. In considering previous autopsy studies, our results support less patient tissue damage when using the Emboless® venous chamber.

#220 Acute vascular response to hemodialysis as measured by serum syndecan-1 and endothelin-1 levels, as well as vascular stiffness

Abstract Background and Aims End-stage kidney disease (ESKD) patients on chronic hemodialysis (HD) have very high cardiovascular risk. Acute vascular changes during dialysis mediated partially by factors of the endothelium may have a crucial role in the cardiovascular (CV) disease of HD patients. Aim To study acute vascular changes during HD measured by applanation tonometry and to assess the role of syndecan-1 (SDC-1), endothelin-1 (ET-1), and traditional and non-traditional CV risk factors in these changes. Method 29 consecutive chronic HD patients (median age: 65.6 ± 10.4 years; 52% men) were included in the study. Pre-, mid-, and post-HD plasma SDC-1 and ET-1 levels and routine biochemical parameters were measured. Applanation tonometry (SphygmoCor, AtCor Medical) was performed before HD. Results As assessed by trend analysis, SDC-1 levels increased significantly during HD (p = 0.004). ET-1 levels were decreasing during HD. Male patients had significantly higher ET-1 levels than women. Patients were divided into 2 groups based on their pulse wave velocity (PWV): PWV ≥12 m/s and PWV &amp;lt;12 m/s. Pre-HD and mid-HD SDC-1 levels were significantly higher in the group with PWV ≥12 m/s (10.174 ± 2.568 vs. 7.928 ± 1.794 ng/ml, p = 0.013, and 10.319 ± 3.482 vs. 8.248 ± 1.793 ng/ml, p = 0.044, respectively). Post-HD ET-1 levels were significantly higher in the patient group having PWV ≥12 m/s (10.88 ± 3.00 vs. 8.05 ± 3.48 pg/l, p = 0.027). Patients having PWV ≥12 m/s had significantly higher pre-HD peripheral and aortic systolic blood pressure than the patients having lower PWV (147.4 ± 73.3 vs. 134.1 ± 72.2 mmHg, p = 0.038, and 130.7 ± 16.6 vs. 122.5 ± 14.9 mmHg, p = 0.016, respectively). Mid-HD and post-HD blood pressures were not different. We found a positive correlation between total cholesterol and the decrease in SDC-1 levels during HD (r = 0.539; p = 0.008). Pre-, mid-, and post-HD SDC-1 correlated significantly with the ultrafiltration volume during HD (r = 0.432, p = 0.019; r = 0.377, p = 0.044; and r = 0.401, p = 0.012, respectively). Conclusion SDC-1 and ET-1 may contribute to the vascular changes observed during HD, and they have correlations with some traditional and non-traditional CV risk factors.

#941 Pentraxin-3 as a marker of coronary artery disease in hemodialysis patients

Abstract Background and Aims Pentraxin-3 (PTX3), a novel inflammatory biomarker, has been recognized as a predictor of cardiovascular events in the general population, including coronary artery disease (CAD). Although PTX3 is elevated in dialysis patients, its potential diagnostic value for the estimation of CAD severity is still insufficiently studied. The aim of this study was to evaluate the association between PTX3 and CAD in hemodialysis patients. Method This cross-sectional study included 60 angina-free chronic hemodialysis patients (60% men, mean age 60 ± 11 years, mean dialysis vintage 26 ± 14 months). Coronary artery calcium score (CACS) and coronary computed tomography angiography (CCTA) were performed to evaluate CAD burden and stenosis severity, which was defined as significant if obstructing more than 50% of the vessel lumen. PTX3 was quantified using an enzyme-linked immunosorbent assay kit. Results Significant coronary artery stenosis was detected in 24 (40%) patients, of which the majority (17; 70.83%) had one-vessel disease. PTX3 was 194.82 ± 68.58 ng/mL in patients with significant CAD, whereas 83.55 ± 11.89 ng/mL in those without significant coronary artery stenosis (p = 0.028). PTX3 levels tend to increase in patients with CACS higher than 200 Agatston units, however statistically significant difference was not reached (p = 0.504). PTX3 levels correlated with age (p &amp;lt; 0.05) and c-reactive protein (p = 0.007), while negatively correlated with body mass index (p &amp;lt; 0.05). Conclusion PTX3 is significantly increased in hemodialysis patients with coronary artery disease. Further studies should elucidate if including PTX3 as a marker for detecting CAD prior to invasive imaging could improve cardiovascular risk stratification even in angina-free hemodialysis patients.