Background: The population of elderly patients undergoing chronic hemodialysis is increasing, and anemia represents a frequent complication. The aim of our study was to evaluate the association between ultrafiltration rate (UFR) in hemodialysis and erythropoietin (EPO) response in elderly patients with end-stage kidney disease (ESKD). Methods: This was a multicenter, retrospective observational study, involving elderly patients (aged 65 years or more) under chronic hemodialysis therapy. Individuals were divided into two groups according to the UFR adjusted to weight (UFR/W): lower (UFR-N) or higher (UFR-H) than 10 mL/h/kg. EPO resistance index (ERI) was calculated. We evaluated the hemogram, reticulocyte count, and quantified markers of iron metabolism and inflammation. Results: A total of 193 patients were enrolled in the study: 141 patients met criteria for inclusion in UFR-N group and 52 in UFR-H group. Compared to UFR-N, patients in the UFR-H group presented significantly higher doses of erythropoiesis-stimulating agents (ESA) and ERI values, with similar hemoglobin (Hb) and inflammatory markers levels. In a sub-analysis, within patients presenting transferrin saturation (TSAT) lower than 20%, a more marked difference in ERI between UFR groups was observed, being much higher in UFR-H compared with UFR-N. In this subgroup (UFR-H with lower TSAT), levels of hepcidin were lower than in the other subgroups. Conclusions: Our data show that UFR appears to be a contributing factor of ESA response in elderly patients under hemodialysis, particularly in those with lower iron availability. These findings suggest that inadequate weight control and/or UF prescription seem to aggravate ESA needs to achieve target Hb.

Anemia is common in patients under regular hemodialysis therapy. Despite treatment with erythropoiesis-stimulating agents (ESA), hypo-responsiveness to this therapy can occur (refractory cases). We studied the association between ESA resistance in hemodialysis patients and potential causes of ineffective treatment, including nutritional, iron metabolism, and inflammatory variables, and dialysis related parameters. We performed a cross-sectional study involving 289 hemodialysis patients. Ultrafiltration rate adjusted to weight (UFR/W), urea reduction ratio (URR) and Kt/V were obtained for the session where blood samples were collected. Blood analyses were performed by using automated technology or by enzyme-linked commercialized immunoassays, as previously described [1]. Erythropoietin (EPO) resistance index (ERI) was calculated by the formula: EPO dose per week (IU)/body weight (kg) /hemoglobin (g/dL). The mean age of patients was 68.7 years (±13.6), 240 patients (83%) were under ESA prescription and 186 (64.4%) were receiving intravenous iron. The median (interquartile range) for ERI was 7.1 (3.7–11.7) IU/kg/g/dL, and for median transferrin saturation (TSAT) was 21.9 (16.8–28.5) %. ERI was positively correlated with levels of soluble transferrin receptor (sTfR, r = 0.556, P = 7.8×10−21; Fig. 1), interleukin (IL)-6 (r = 0.196, P = 0.002), pentraxin 3 (r = 0.192, P = 0.003), C-reactive protein (r = 0.130, P = 0.043) and UFR/W values (r = 0.135, P = 0.037) and inversely correlated with body mass index (r = −0.179, P = 0.005) and levels of iron (r = −0.382, P = 9.2×10−10), TSAT (r = −0.340, P = 6.8×10−8), hepcidin (r = −0.197, P = 0.002) and albumin (r = −0.166, P = 0.010). By performing multivariate linear regression analysis (after normalization of non-normally distributed data), levels of sTfR (β = 0.487, P < 0.001), iron (β = −0.176, P = 0.003), and IL-6 (β = 0.111, P = 0.035), and UFR/W values (β = 0.168, P = 0.001) were independent predictors of ERI. When iron repleted patients (ferritin ≥ 100 µg/L and TSAT ≥ 20%) receiving EPO therapy were analyzed separately (n = 138), sTfR and UFR/W were kept in the regression model as predictors of ERI (β = 0.504, P < 0.001 and β = 0.207, P = 0.006, respectively); within these patients, those with UFR/W > 10 ml/h/kg presented higher ERI than those below 10 ml/h/kg (Fig. 2). Besides lower iron, raised UFR/W and IL-6 are independently associated with hypo-responsiveness to ESA. sTFR seems to be a valuable tool to access ESA-driven erythropoiesis in hemodialysis patients, particularly in iron repleted patients. Our results support the idea that the modulation of inflammation and UFR prescription can improve anemia management.

Pediatric patients with end-stage kidney disease (ESKD) often require hemodialysis (HD) when transplantation is not feasible. Arteriovenous fistulas (AVFs) are the preferred vascular access for HD due to their lower rates of infection and thrombosis compared to central venous catheters (CVCs). However, the creation and maintenance of AVFs in children present significant challenges, including smaller vessel size and higher risks of primary failure. This study aims to describe and update our experience in AVF creation and assess its patency in children and adolescents undergoing HD. We retrospectively analyzed all the AVFs performed in our center in patients under 18 from January 2006 to December 2024. Collected data included demographics, clinical parameters, dialysis history, surgical details, and laboratory results. We reviewed medical records and entered data into a database for analysis using SPSS software. A total of 46 AVFs were created in 36 pediatric patients. The median age at first AVF construction was 13.0 years (range: 4.8–17.9). Congenital anomalies of the kidney and urinary tract were the most frequent cause of ESRD (n = 21, 58.3%), and most patients (n = 27, 75.0%) were already on kidney replacement therapy. The median follow-up was 11 months (range: 1–98.4), and 61.1% of patients (n = 22) were transplanted during this period. The mortality rate was 5.6% (n = 2). Radiocephalic AVFs were the initial choice in 47.2% of cases (n = 17), representing 37.0 % of all AVFs. Brachiocephalic AVFs were initially created in 30.6% of patients (n = 11) and comprised 23.9% of all AVFs, including revisions. Brachiobasilic AVFs were the initial choice in 22.2% of cases (n = 8) and accounted for 17.4% of the total. Primary AVF failure occurred in 27.8% of cases (n = 10), with successful re-intervention at the same site in 40.0% of these failures (n = 4). Primary and secondary patency rates at one year were, respectively, 62.2% and 91.1%. No statistically significant relationship was found between the occurrence of primary AVF failure and either the age at first AVF creation and AVF location. Regarding AVF complications: Thrombosis was the most common complication, occurring in 23.9% of AVFs. Stenosis was observed in 17.4%, distal ischemia in 4.3%, and high flow/aneurysmal dilations also in 6.5%. A negative correlation (Pearson coefficient −0.394, significance level 0.018) was seen between the age of patients and the presence and number of complications. Arteriovenous fistulas (AVFs) are increasingly acknowledged as a reliable and efficacious option for hemodialysis in pediatric patients. Our findings indicate favorable outcomes in this group, with elevated primary and secondary patency rates, irrespective of AVF location.

Background:Limited data exist on rehospitalization in paediatric dialysis patients. The objective of this study was to identify indications, rates and risk factors for 30-day readmissions in this population. Methods:We used a prospective multinational, multicentre cohort study of haemodialysis (HD) and peritoneal dialysis (PD) patients discharged between July 2017 and July 2018. Readmission was identified as repeat hospitalization within 30 days of a prior (index) admission. Potentially preventable readmissions were clinically related to the initial admission. Early readmissions were those occurring within 7 days of discharge. The primary outcome was 30-day readmission. Secondary outcomes included potentially avoidable and early readmissions. Results:A total of 54 (31%) of 176 patients (102 PD, 74 HD) had at least one readmission; 84 (18%) discharges were followed by readmission. PD and HD patients had similar readmission rates {30.4% versus 31.1%; hazard ratio [HR] 1.06 [95% confidence interval (CI) 0.61-1.81]}. Compared with PD, HD patients had a significantly shorter time to readmission (8 versus 14 days; P = .019), higher early readmission rates (46% versus 18%; P = .010) and risk [odds ratio (OR) 3.87 (95% CI 1.35-11.11)]. Main readmission causes were dialysis access-related non-infectious complications (31%) and access infections (22.7%); 47% of readmissions were potentially avoidable. Lower haemoglobin levels were linked to readmission [HR 0.78 (95% CI 0.64-0.95)]. Bicarbonate use was associated with a 51% lower readmission risk [HR 0.49 (95% CI 0.24-0.99)]. Neurological comorbidity [OR 7.00 (95% CI 1.04-47.22)] and partial recovery [OR 56.45 (95% CI 3.02-1053.10)] were risk factors for avoidable readmission. Risk of avoidable and early readmission decreased with age [OR 0.98 (95% CI 0.97-0.99) and OR 0.99(95%CI 0.98-0.99), respectively]. Conclusions:Readmissions are common in paediatric dialysis patients, with a substantial proportion being potentially preventable. To reduce rehospitalizations, interventions should target modifiable factors such as access complications, anaemia and incomplete recovery at discharge, while recognizing non-modifiable risks like HD and younger age to identify high-risk patients.

Patients with neurogenic bladder (NB) can develop progressive chronic kidney disease (CKD), so early detection of estimated glomerular filtration rate (eGFR) reduction is essential to prevent morbimortality. Due to decreased muscle mass in children with NB, there may be significant inaccuracy when using creatinine-based eGFR formulas. This study aims to analyse eGFR calculated by different equations using serum creatinine (Cr) and/or cystatin C (CysC) and compare between patients with and without motor neurological injury. A retrospective study was conducted on pediatric patients with NB and CKD with stable renal function (stages 1 and 2), based on Chronic Kidney Disease in Children (CKiD) Under25 (U25)-Cr formula, from a Pediatric Nephrology Unit of a tertiary hospital. The eGFR was calculated using CKiD U25-Cr, CKiD U25-CysC, European Kidney Function Consortium (EKFC)-Cr and EKFC-CysC equations. Forty-four patients were included in the analysis, with a median age (IQR) of 14.2 years (9.1–17), 50% (n = 22) were male, 63.6% (n = 28) had lipo/myelomeningocele and 72.7% (n = 32) were classified as stage 1 CKD. The median (IQR) eGFR (ml/min/1.73 m2) calculated by different formulas was: CKiD U25-Cr 101.0 (79.6–130.7); CKiD U25-CysC 73.6 (61.9–93.5); EKFC-Cr 110.4 (86.9–123.6) and EKFC-CysC 84.6 (70.7–97.9). When compared to CKiD U25-Cr, the CKiD U25-CysC and EKFC-CysC formulas showed significantly lower values of eGFR (p < 0.001), while EKFC-Cr was similar (P = 0.076). When CKiD U25-CysC and EKFC-CysC equations were used, 40.9% and 44.2% of the patients respectively, moved to a more advanced CKD stage. In patients on wheelchair or orthosis, with more muscle atrophy (52.3%, n = 23), the median eGFR calculated using the CKiD U25-Cr and EKFC-Cr equations was significantly higher (P = 0.04 and P = 0.011, respectively) when compared to those with autonomous gait. However, there were no differences between the two groups when using CKiD U25-CysC and EKFC-CysC-based equations (P = 0.698 and P = 0.525, respectively). In pediatric patients with NB and muscle mass depletion Cr-based formulas can overestimate eGFR and delay the diagnosis and correct staging of CKD. CysC seems to be a more reliable and earlier marker of kidney dysfunction, especially in those with greater muscular atrophy, thus being a valuable tool for identification of pediatric patients with NB who may benefit from early Pediatric Nephrology referral.

INTRODUCTION:Recent findings suggest that the four-variable Kidney Failure Risk Equation (KFRE) may be useful in predicting the likelihood of allograft failure in adult kidney transplant (KT) recipients. However, research on its application in pediatric patients is lacking. This study aimed to assess the accuracy of the four-variable KFRE for prediction of the two-year and five-year risk of allograft failure in a cohort of pediatric KT recipients. METHODS:A retrospective observational study of patients undergoing KT in a tertiary pediatric nephrology unit between 2007 and 2017 was conducted. The KFRE risk scores were determined using data collected one-year post-transplantation. Discrimination and calibration properties of the four-variable KFRE were assessed through the area under the receiver operating characteristic curves (AUC) and calibration plots. RESULTS:Fifty-nine patients with a median age of 12.4 (9.1-15.7) years at KT were included. Eleven (18.6%) were living donor recipients. The median estimated glomerular filtration rate one-year post-transplantation was 62.0 (49.0-75.0) mL/min/1.73 m2. One (1.7%) and three (5.1%) patients experienced allograft failure within two and five years following the one-year post-transplantation date, respectively. The four-variable KFRE showed excellent and very good discrimination for the two-year and five-year risks, respectively (AUC 0.966, 95% confidence interval (CI) 0.914-1.000; AUC 0.887, 95% CI 0.732-1.000). Calibration plots demonstrated imprecise calibration. CONCLUSION:The four-variable KFRE shows promise in predicting kidney failure progression in pediatric KT recipients with a functioning allograft one-year post-transplantation. Larger-scale studies are essential to confirm its predictive accuracy and establish more definitive conclusions.

Worldwide, the number of elderly individuals receiving chronic hemodialysis is rising. The aim of our study was to evaluate several clinical and analytical biomarkers in chronically dialyzed patients and analyze how they change with age. A cross-sectional study was performed by evaluating 289 end-stage renal disease patients undergoing dialysis. We evaluated the hemogram, adipokines, the lipid profile, and several markers related to inflammation, endothelial function/fibrinolysis, nutrition, iron metabolism, and cardiac and renal fibrosis. Clinical data and dialysis efficacy parameters were obtained from all patients. The relationships between studied biomarkers and age were assessed by a statistical comparison between younger (adults with age < 65 years) and older (age ≥ 65 years) patients and by performing regression analysis. Participants presented a mean age of 68.7 years (±13.6), with 66.8% (n = 193) being classified as older. Compared to younger patients, older patients presented the following: (a) significantly lower values of diastolic blood pressure (DBP) and ultrafiltration volume; (b) lower levels of phosphorus, uric acid, creatinine, and albumin; and (c) higher circulating concentrations of tissue-type plasminogen activator (tPA), D-dimer, interleukin-6, leptin, N-terminal pro B-type natriuretic peptide, and tissue inhibitor of metalloproteinase-1. In the multiple linear regression analysis, DBP values, tPA, phosphorus, and D-dimer levels were independently associated with the age of patients (standardized betas: −0.407, 0.272, −0.230, and 0.197, respectively; p < 0.001 for all), demonstrating relevant changes in biomarkers with increasing age at cardiovascular and nutritional levels. These findings seem to result from crosstalk mechanisms between aging and chronic kidney disease.

Abstract Background and Aims Emerging evidence suggests that the 4-variable Kidney Failure Risk Equation (KFRE) can be used to predict the risk of graft failure in adult transplant recipients. However, research studies in pediatric patients are lacking. This study aimed to validate the 4-variable KFRE (age, sex, estimated glomerular filtration rate [eGFR], and urine albumin-to-creatinine ratio [uACR]) for prediction of the 2- and 5-year risk of graft failure in a group of pediatric transplant patients. Method A retrospective observational study involving 59 pediatric patients who underwent kidney transplant between January 2007 and December 2017 was conducted. The KFRE risk scores were calculated with data collected at 1-year post-transplantation. The area under the receiver operating characteristic curves (AUC) and calibration plots were used to assess the discrimination and calibration properties of the 4-variable KFRE in predicting the risk of graft failure at 2 and 5 years from the point of the 1-year post-transplantation measurements. Results Among the 59 patients, 41 (69.5%) were male, with median age of 12.8 years (interquartile range 9.2-15.7) at the time of the kidney transplant. Eleven (18.6%) were living donor recipients. Median eFGR at 1-year post-transplantation was 62.0 mL/min/1.73 m2 (50.0-76.5); 1 (1.7%) and 3 (5.1%) patients developed graft failure within 2 and 5 years from the point of the 1-year post-transplantation measurements, respectively. The 4-variable KFRE showed excellent discrimination for the 2-year risk (AUC 0.966, 95% confidence interval [CI] 0.914-1.000) and very good discrimination for the 5-year risk (AUC 0.887, 95% CI 0.732-1.000). Calibration plots however showed imprecise calibration. A discernible trend was apparent in this sample, suggesting that living donor recipients have increased probability of experiencing graft failure in the first 5 years (p = 0.069). Conclusion The 4-variable KFRE may be of interest in predicting kidney failure progression in pediatric kidney transplant recipients using data at 1-year post-transplant, however to substantiate these findings and ensure the robustness of conclusions, larger-scale studies should be conducted.

Abstract Background and Aims In chronic kidney disease (CKD), hypertension (HT) is commonly found during its development and is a leading cause for its progression. HT, dyslipidemia and visceral obesity are among the components of metabolic syndrome (MetS) and seem to associate with progression of CKD to end-stage kidney disease (ESKD). Enhanced levels of soluble tumor necrosis factor receptor 2 (sTNFR2) are known to associate with progressive CKD; and this biomarker was reported as an independent predictor of all-cause mortality in ESKD patients under dialysis. Concerning the TNFRSF1B gene, the polymorphism rs1061624 (A > G), located in the 3′-untranslated region (3′-UTR), was associated with the development of HT in men and with increased risk of MetS. The aim of this study was to determine the genotype frequencies of TNFRSF1B rs1061624 in ESKD patients with and without HT, and to evaluate its relationship with the circulating levels of some MetS biomarkers. Method We studied 277 ESKD patients on dialysis (recruited between 2016-2019), 170 diagnosed with HT and 107 without HT (no-HT group); age, sex, body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP) and statin therapy were recorded. Real time PCR TaqMan SNP genotyping assay was used to assess genotype frequencies of TNFRSF1B rs1061624. We also evaluated the conventional lipid profile and the levels of oxidized low-density lipoprotein, adiponectin and leptin. Results The genotype frequencies in patients with and without HT were different (P = 0.002); the AA genotype was less frequent in HT than in no-HT group, while GG and AG genotypes were more frequent. Considering the AA genotype carriers, HT ESKD patients (n = 23), compared to the no-HT group (n = 33), presented lower adiponectin levels (P = 0.025); for the AG genotype carriers, HT group (n = 89) presented a trend towards lower adiponectin concentrations (P = 0.055), and were younger than no-HT patients (n = 48; P<0.001); in both comparisons, groups were matched for sex, BMI and number of patients under statins treatment, and in the first case also for age. Considering GG genotype, HT patients (n = 58) only differed from no-HT subjects (n = 26) in SBP, that was higher (P<0.001). Among HT patients, AG genotype carriers presented higher DBP (P = 0.004), lower values of leptin (P = 0.012) and leptin/adiponectin ratio (P = 0.022) and were younger (P<0.001) than GG genotype patients; compared to AA carriers, cholesterol levels were lower (P = 0.012). For the no-HT group, AG genotype patients presented lower DBP (P = 0.008) than AA genotype carriers. Conclusion The genotype frequencies were different in ESKD patients with and without HT, being G allele more frequent in HT. The HT ESKD patients with the AA or the AG genotypes seem to present lower adiponectin levels than the ESKD no-HT patients with the same genotypes. Acknowledgements This work was financed by CESPU, through the project SNPsCKD-GI2-CESPU-2022; FCT, in the scope of the project UIDP/04378/2020 and UIDB/04378/2020 of the Research Unit on Applied Molecular Biosciences—UCIBIO and the project LA/P/0140/2020 of the Associate Laboratory Institute for Health and Bioeconomy—i4HB.

Abstract Background and Aims There is a high-risk of progressive chronic kidney disease (CKD) in patients with neurogenic bladder (NB) and early detection of estimated glomerular filtration rate (eGFR) reduction is essential, preventing delayed diagnosis. Creatinine-based formulas can overestimate eGFR in these patients due to decreased muscle mass. This study aims to compare eGFR calculated by different equations using serum creatinine (Cr) and/or cystatin C (CysC), in children with NB, and analyse the influence of demographic variables and proteinuria. Methods Data on pediatric patients with NB and CKD stage 1 and 2, based on eGFR calculated by the CKiD-Cr formula, were collected from January 2009 to December 2022, in a Pediatric Nephrology Unit from a tertiary hospital. The eGFR was calculated using CKiD CysC, Schwartz combined Cr/CysC, Zapitelli-CysC and Zapitelli combined Cr/CysC formulas. Proteinuria was defined by urine protein-to-creatinine ratio greater than 0.2 (mg/mg). Results Fifty patients were evaluated, with a median (25th-75th percentile) age of 14.2 (9.0-16.7) years, 48% (n = 24) female, with a median height of 142 (119.8-154.3) cm, mostly below to 5th percentile (64%, n = 32) and a median body mass index of 20.5 (15.5-26.7) kg/m2, 58% (n = 29) of patients had lipo/myelomeningocele and 76% (n = 38) were classified as stage 1 CKD. The median eGFR (ml/min/1.73m2) calculated by different formulas was: CKiD-Cr 108.1 (89.2-129.6); CKiD-CysC 77.1 (59.7-87.7), CKiD- Cr/CysC 86.6 (67.4-98.1); Zapitelli-CysC 83.3 (63.3-95.7) and Zapitelli combined- Cr/CysC 101.4 (75.5-121.2). When compared to CKiD-Cr, all the CysC-based formulas showed significantly lower values of eGFR (p<0.01). No statistical differences were obtained in eGFR calculated by CKiD-Cr and CKiD-CysC equations regarding age, sex, percentile of height or body mass index. In patients without independent gait (wheelchair or orthosis), with more muscle atrophy and underdeveloped lower limbs (54%, n = 27), the eGFR calculated by CKiD- Cr equation was higher than in the patients who are ambulatory (119.0 (102.8-150.0) vs 91.6 (64.5-111.8); p<0.01). On the other hand, there were no differences regarding eGFR obtained by CKiD-CysC in those two groups of patients (p = 0.640). Proteinuria was detected in 39% (n = 15) of the patients with stage 1 CKD and of these 87% (n = 13) had CKD upstaging using CKiD-CysC equation. In addition, the difference between the median Cr-eGFR and CysC-eGFR was significantly higher in the group of patients with proteinuria (53.0 (36.2-59.7) vs 32.6 (13.4-45.9); p = 0.007). Proteinuria was significantly higher in the group of children with more muscle atrophy, without independent gait (wheelchair or orthosis) compared to ambulatory (0.30 (0.12-0.43) vs 0.12 (0.06-0.20); p = 0.021). Conclusions In pediatric patients with NB and poor muscle mass Cr-based formulas can overestimate eGFR and delay the diagnosis and correct staging of CKD. In these patients CysC-based equations seem to be more reliable in assessing kidney function. In children with NB proteinuria appears to be a possible early and sensitive marker of CKD progression, mostly in those with more muscle depletion.

Previous studies investigating hospitalizations in dialysis patients have focused primarily on patient-centered factors. We analyzed the impact of hospital and dialysis unit characteristics on pediatric dialysis patients’ hospitalizations for access-related complications (ARCs). This cross-sectional study involved 102 hemodialysis (HD) and 163 peritoneal dialysis (PD) patients. Data between July 2017 and July 2018 were analyzed. Children’s hospitals (CHs) had more pediatric nephrologists and longer PD experience (years) than general hospitals (GHs) (p = 0.026 and p = 0.023, respectively). A total of 53

Abstract Background and Aims In the pediatric population, transplantation remains the first-line therapy in patients with end-stage renal disease (ESRD). However, it is not always possible, increasing the need for other kidney replacement therapy (KRT) modalities, and hemodialysis (HD) has been growing as a modality choice in recent years. To provide quality HD treatment, efficient vascular access is mandatory, and the arteriovenous fistula (AVF) is advocated as the best long-term access option. However, its creation is technically challenging, and its development and maintenance are some of the most difficult elements in the pediatric population. In this study, we describe our experience in the utilization of AVFs in children and adolescents on HD. Method We conducted a retrospective study including all the AVFs performed in our center on underage patients between January 2006 and December 2022. We reviewed the medical records, collected data on demographic variables, AVF characteristics, blood test results, and clinical outcomes. Statistical analysis was performed using SPSS software. Results Forty-three AVFs were performed in 32 pediatric patients. The median age at first AVF construction was 13.5 years (min 4.8; max 17.9). The most frequent etiology of ESRD was congenital anomalies of kidney and urinary tract (n = 20, 62.5%) and most patients (n = 24, 75.0%) were already receiving KRT. Median follow-up time was 16.4 months (min 1; max 98.4) and, at the end of the follow-up period, most patients (n = 22, 68.8%) were transplanted. The mortality rate was 6.3% (n = 2). In what concerns to the location of the AVF, radiocephalic was the first choice in 46.9% of the cases (n = 15), accounting for 34.9% of the total AVFs. Brachiocephalic location was used in 34.4% (n = 11) of first fistulas and 6 subsequent accesses, accounting for 39.5% of the total AVFs. The brachiobasilic location was chosen in 18.8% (n = 6) of the first AVFs and 25.6% of the total AVFs. Primary AVF failure occurred in 26.6% (n = 11) cases and, in 4 of these (36.4%), it was possible to successfully use the same location for a second AVF. We observed no statistical association between primary AVF failure dysfunction and gender, age at the construction of the first fistula, AVF location, or dialysis vintage. Platelet-lymphocyte (PLR) and neutrophil-lymphocyte (NLR) ratios also did not differ between groups. Primary and secondary patency rates at one year were, respectively, 62.5% and 93.8%. With respect to total AVF complications, we observed: thrombosis (27.9%), stenosis (18.6%), distal ischemia induced by vascular access (4.7%), and high flow/aneurismatic dilations (18.6%). The presence of complications was statistically related to age (p = 0.046), with more events in older patients at the time of AVF construction. There was no statistical difference between complications’ occurrence and AVF type, sex, gender, PLR, and NLR. Conclusion The utilization of AVF for HD has been growingly recognized as a safe and efficient alternative for the performance of KRT in pediatric patients. Although larger studies are needed, we demonstrate positive results in its usage in a pediatric population, with high primary and secondary patency rates. These outcomes were independent of the AVF location. We also advocate AVF usage in younger patients, as complications were associated with older age. PLR and NLR, which are emerging biomarkers for systemic inflammation, were not associated with AVF dysfunction, aligning with the results of other studies in pediatrics.

Background and hypothesis. Hospital admissions in pediatric dialysis patients need to be better studied, and most existing studies are retrospective and based on registry data. This study aimed to analyse and compare hospital admission rates, causes, length of stay (LOS), and outcomes in children treated with peritoneal dialysis (PD) and hemodialysis (HD).Methods. Data from 236 maintenance PD and 138 HD patients across 16 European dialysis centers were collected between 1 July 2017 and 30 June 2018. A total of 178 hospitalized patients (103 PD, 75 HD) were included for further analyses.Results. There were 465 hospitalization events (268 PD, 197 HD) with a rate of 0.39 admissions per 100 patient-days at risk (PDAR) and 2.4 hospital days per 100 PDAR. The admission rates were not significantly different between HD and PD patients. The most common causes of hospitalization were access-related infections (ARI) (17%), non-infectious complications of access (NIAC) (14%), and infections unrelated to access (12%). ARI was the leading cause in PD patients (24%), while NIAC was more common in HD patients (19%). PD patients had more ARIs, diagnostic procedures, and treatment adjustments (P < .05), while HD patients had more NIACs, infections unrelated to access, access placement procedures, and interventional/surgical procedures (P < .001). LOS was longer with acute admissions than non-acute admissions (P < .001). Overall LOS and LOS in the intensive care unit were similar between HD and PD patients. High serum uric acid and low albumin levels were significant predictors of longer LOS (P = .022 and P = .045, respectively). Young age, more significant height deficit, and older age at the start of dialysis were predictors of longer cumulative hospital days (P = .002, P = .001, and P = .031, respectively).Conclusion. Access-related complications are the main drivers of hospitalization in pediatric dialysis patients, and growth and nutrition parameters are significant predictors of more extended hospital stays.

Abstract Background and Aims Enhanced levels of soluble tumor necrosis factor receptor 2 (sTNFR2) are known to associate with progressive chronic kidney disease (CKD), and is pointed as a potential biomarker for early detection of CKD; moreover, it has been reported as an independent predictor of all-cause mortality in end-stage renal disease (ESRD) patients under dialysis. Despite the increase in TNFR2 and in other inflammatory markers, recognized as risk factors for mortality in dialysis patients, the hypothesis that genetic polymorphisms of those biomarkers might modulate the inflammatory response and, thereby, the patients’ survival predisposition, has been poorly studied. Concerning TNFR2 genetic variants, a single nucleotide polymorphism in TNFR2 (+ 676 T/G; rs1061622), that results in amino acid change at position 196 (Met/Arg), was associated with higher levels of sTNFR2 in inflammatory conditions. The aim of this study was to determine the allelic frequencies of TNFR2 in ESRD patients and controls, and to evaluate its relationship with the circulating levels of inflammatory biomarkers. Method We studied 277 ESRD patients on dialysis and 32 controls, matched for gender, body mass index, and, as far as possible, for age. Real time PCR TaqMan SNP genotyping assay was used to assess allelic frequencies of TNFR2 (rs1061622). We also evaluated the circulating levels of TNF-alpha, sTNFR2, ferritin, hepcidin, elastase and cell-free DNA (cfDNA). Deaths occurring along 1-year follow-up period were recorded and mortality rates were assessed. Results ESRD patients presented higher levels of all studied biomarkers, as compared to controls; their overall mortality rate was 10.5%. Allelic frequencies in ESRD patients and controls were similar for TNFR2 (rs1061622) considering the homozygous and heterozygous individuals (χ2, p = 0.518). Concerning sTNFR2 values, no significant differences were observed between patients with genotypes TT, GG or TG. The GG genotype patients, compared to TT genotype carriers, presented significantly lower ferritin (p = 0.048), hepcidin (p = 0.038), elastase (p = 0.006) and cfDNA levels (p = 0.016); and compared to TG genotype patients, showed significantly lower ferritin (p = 0.039) and a trend towards lower values of hepcidin (p = 0.097), elastase (p = 0.079) and cfDNA (p = 0.0164). TG genotype patients showed higher TNF-alpha (p = 0.049) and a trend towards lower elastase (p = 0.081) than TT genotype subjects. The GG genotype patients presented a trend towards lower mortality rate (6.3%, 7.5%, and 12.4% for GG, TG and TT, respectively). Conclusion No differences were found in the allelic frequencies between controls and ESRD patients. The GG genotype patients for TNFR2 rs1061622 polymorphism showed decreased levels of inflammation, suggesting a more favorable inflammatory response, which is usually associated to a lower mortality risk in these patients. In accordance with the scientific community, recommending studies on genetic survival predisposition in dialysis patients, the polymorphisms of TNFR2 and of other inflammatory biomarkers deserve further studies. Acknowledgements: This work was financed by CESPU, through the project SNPsCKD-GI2-CESPU-2022; FCT, through the project UIDP/04378/2020 and UIDB/04378/2020 of the Research Unit on Applied Molecular Biosciences—UCIBIO and the project LA/P/0140/2020 of the Associate Laboratory Institute for Health and Bioeconomy—i4HB.

Abstract Background and Aims Hepatocyte nuclear factor 1β (HNF1β)-associated disorder is a rare entity that may present with a wide range of clinical phenotypes. Genetic transmission is autosomal dominant, penetrance is incomplete, and expression is variable, which can contribute to different clinical presentations, raising difficulties to reach the diagnosis. The most common findings are renal cysts, responsible for kidney function decline, as well as diabetes mellitus, among other possible organs’ manifestations such as the pancreas, liver, brain and parathyroid gland. The disease arises through monoallelic single nucleotide deleterious variants (SNVs) or whole-gene deletions, in the chromosome 17q12. Method Retrospective analysis of patients with HNF1β-associated disease followed in pediatric nephrology unit, throughout the last 10 years (2013-2022), in our pediatric tertiary center. Data regarding demographic variables, along with family history, relevant clinical information and genetic variants were collected from electronical clinical files. Results A total of 6 patients were followed in our centre, mostly males (n = 5). Regarding age at diagnosis, two patients were diagnosed prenatally, owing to positive familial history and renal cysts, while for the other 4 patients (de novo mutations) the age at diagnosis ranged from one to 13 years-old (yo). Five patients presented with renal cysts, while the other patient presented with unilateral urinary tract dilation. Only one patient presented with diabetes mellitus. Regarding other possible comorbidities, two patients presented with neurodevelopmental disorders and one with hypertension. At presentation, 3 patients had chronic kidney disease stage 3. The mean decrease in glomerular filtration rate was 1.44 ml/min/year (according to Schwartz “bedside” formula). Creatinine levels almost doubled in 3 of the patients since referral (adolescents currently with 1.5-2 mg/dL), while remaining in the normal range in the other patients. Two patients presented with low grade proteinuria during follow-up (max protein/creatinine ratio 0.36 g/g). Values of calcium, transaminases and uric acid were normal in all patients. Familial history of kidney disease, namely cysts or chronic kidney disease, was positive in 3 patients. In terms of genetic transmission, 3 patients had SNVs, while the other 3 presented with larger deletions in chromosome 17q12. Conclusion In conclusion, in these patients, a high degree of suspicion is needed for diagnosis, owing to the rarity of the disease and heterogeneity of its manifestations. A multidisciplinary approach and genetic counseling are determinant for disease management. Families of the affected individuals should be tested, even if asymptomatic, to determine if the HNF1β variant was inherited or occurred de novo. Given the small number of patients, it would be important to widen the sample through a multicentric study.