Clinical Journal of the American Society of Nephrology

Introduction: B cell depletion with rituximab leads to complete or partial remission (CR/PR) in only ~60% of patients with primary membranous nephropathy (PMN). Adding belimumab to rituximab may result in greater depletion of memory B cells, limit the re-emergence of autoreactive B cells, and improve clinical responses. Methods: REBOOT Part A (NCT03949855) is a single arm, open-label, pharmacokinetic study where all participants had proteinuria [≥] 4g/day and detectable serum anti-phospholipase A2 receptor (anti-PLA2R) antibodies. Participants received belimumab 200 mg subcutaneously weekly for 52 weeks and rituximab 1000 mg intravenously at weeks 4 and 6. Assessments included belimumab exposure at week 4 and CR/PR at week 104. Results: Seventeen participants started belimumab. Belimumab exposure was not significantly reduced in those with high (> 9 g/day) proteinuria at week 4. Among all treated participants, 59% (10/17) achieved CR/PR at week 104, while in per protocol analyses, 91% (10/11) achieved CR/PR at week 104. All participants in per protocol analyses had normal serum albumin and undetectable serum anti-PLA2R by week 104. Circulating memory B cells increased before rituximab and were depleted by rituximab. B cell re-constitution occurred after week 52 with primarily naive and transitional B cells. Belimumab with rituximab was well-tolerated, with one participant discontinuing belimumab due to infection. Conclusion: In this study, a high proportion of participants receiving belimumab with rituximab achieved CR/PR. Thus, a multi-targeted approach to B cell depletion may improve immunologic and clinical outcomes in PMN and is being studied in a larger, randomized, placebo-controlled clinical trial.

Background: Fibrosis, characterised by excessive accumulation of collagen type I (COL1), is a common feature of chronic diseases, including liver diseases (LDs), chronic kidney disease (CKD) and heart failure (HF). COL1 degradation products can be detected in urine by proteomics/ peptidomics analyses and may serve as non-invasive biomarkers of fibrosis. We aimed to identify a common molecular signature of fibrosis across these diseases that may ultimately guide interventions to slow disease progression and prevent organ damage. Methods: Using capillary electrophoresis coupled to mass spectrometry (CE-MS), naturally occurring COL1 degradation products (peptides) in the urine of patients with fibrotic disease, LDs (n=127), CKD (n=263) or HF (n=187), were investigated and compared with the same number of matched controls. Disease-associated COL1 peptides were identified separately for each condition, and peptides showing consistent associations across the three diseases were selected to define a common fibrosis signature. A support vector machine model based on the selected peptides was developed and validated in independent cohorts of patients with LDs (n=110), CKD (n=93), HF (n=32) and controls (n=643). Results: We identified a common fibrotic signature consisting of 50 COL1 degradation products, mainly downregulated in fibrosis. A model based on these peptides achieved a strong performance, with an area under the receiver operating characteristic curve (AUC) of 0.935 (95% confidence interval (CI) 0.917-0.953, p<0.0001) in an external validation cohort comprising pooled disease groups (LDs, CKD, and HF) and controls. Performance was maintained in LDs, CKD and HF, with AUCs of 0.917 (95% CI 0.890-0.944, p<0.0001), 0.951 (95% CI 0.931-0.971, p<0.0001) and 0.950 (95% CI 0.903-0.997, p<0.0001), respectively. The model scores were significantly associated with fibrosis stage in LDs (p=0.0097) and with interstitial fibrosis and tubular atrophy in CKD (p=0.045). Conclusion: A model of urinary COL1 peptides captures a shared collagen degradation signature across organs and diseases, enabling the non-invasive assessment of fibrosis irrespective of its origin. As these peptides exclusively reflect collagen degradation, the findings suggest impaired collagen degradation as a driver in fibrosis. Future clinical studies are warranted to evaluate the utility of this model for early fibrosis detection and earlier implementation of anti-fibrotic interventions.

Background: The dietary approaches to stop hypertension (DASH) diet is often recommended to patients with chronic kidney disease, although evidence regarding its efficacy in this population is limited. Our study tested the hypothesis that increased adherence to the dietary approaches to stop hypertension (DASH) diet score would be associated with longer time to kidney function decline among Veterans. Methods: We conducted a retrospective cohort study of 251,921 Veterans enrolled in the Million Veteran Program (MVP). The DASH diet score was calculated from the food frequency questionnaire and categorized into tertiles. The primary outcome was a composite of: Kidney event or death, where a kidney event was defined as a sustained 40% decline in estimated glomerular filtration rate (eGFR) or end-stage kidney disease (ESKD). Cox regression models compared the hazard for both outcomes by DASH score tertiles. We examined modification by ancestry, sex and other clinical characteristics Results: The median age was 67 years and 90% of Veterans were men. There were 59,269 (23.5%) who experienced the primary composite outcome, during the maximum follow-up of 10 years (median 6.1 years). Crude incidence rates for the kidney event and death outcome were 43.3, 40.4, and 36.8 per 1000 person-years of DASH score by tertiles. DASH score was associated with a lower hazard ratio (HR) for the primary composite outcome; third vs first tertile 0.81 (95% Confidence Interval (CI) 0.80 - 0.83) and second vs first tertile HR 0.90 [95% CI 0.88 - 0.92]. In subgroup analysis for individuals of African ancestry, Admixed American, and Females, only the third tertile of the DASH score was associated with a statistically significant reduction in composite outcome. Conclusion: Beneficial associations of the DASH diet were observed across subgroups. Future research is needed to understand gene and environmental factors that influence the observed subgroup differences

Background: ALECT2 is the third most common cause of renal amyloidosis in the United States, with a strong predilection for Hispanic patients in the Southwest. (PMID:24522497) Despite its regional prevalence, the data on the trajectory of kidney function decline and post-transplant outcomes remain poorly characterized. Methods: This is a retrospective study of patients diagnosed with ALECT2 by kidney biopsy at UNM from January 2014 to April 2024. Pre- and post-biopsy eGFR trajectories and post-transplant allograft function were analyzed. Results: 12 patients had pre-biopsy data available, with the mean age at diagnosis 64 SD 12.0 years, 8(67%) were females, and 8 identified as Hispanic. Mean eGFR at diagnosis was 31 (SD 29) indicating advanced kidney disease with 67% diagnosed as CKD stage 4 or 5. Concomitant kidney pathology was identified in 50% with diabetic nephropathy being present in 2/3 of those. A significant change in the eGFR trajectory identified at the time of biopsy through change point analysis [Figures A,C,D] Among four patients who underwent kidney transplantation, allograft eGFR remained stable over more than 60 months of follow-up [Figure D] Conclusion: In this cohort of predominantly Hispanic patients, ALECT2 amyloidosis presented with advanced CKD and accelerated loss of kidney function, which prompted a biopsy that detected the disease. Post- transplant allograft function was well maintained, supporting kidney transplantation as a viable treatment strategy for ALECT2-associated kidney disease.

Background: Whether benchmark performance reflects robust clinical reasoning rather than surface-level pattern recognition remains uncertain. We evaluated the robustness of state-of-the-art large language models (LLMs) on nephrology board renewal questions using "None of the other answers" (NOTA) substitution. Methods: From 210 Japanese Society of Nephrology board renewal questions (2014-2023), two nephrologists independently reviewed all items. Questions in which NOTA became the sole correct answer after replacement were included, yielding 145 validated questions. GPT-5, GPT-4o, Gemini 2.5 Pro, and Gemini 2.0 Flash were evaluated via application programming interfaces under default settings. The primary endpoint was accuracy, and paired differences were assessed using the exact two-sided McNemar test. Results: Accuracy was significantly lower after NOTA substitution for all models: GPT-4o, 66.21% to 19.31% (drop, 46.90 percentage points [pp]); GPT-5, 87.59% to 73.10% (14.48 pp); Gemini 2.0 Flash, 58.62% to 31.03% (27.59 pp); and Gemini 2.5 Pro, 86.90% to 55.86% (31.03 pp); all P < .001. GPT-5 showed the smallest decline and the highest accuracy in both versions. Conclusions: All evaluated LLMs showed a significant robustness gap after NOTA replacement. Newer models may be more robust, but multiple-choice accuracy remains an incomplete measure of clinical reasoning robustness.

Background: Current understanding of acute kidney injury (AKI) risk factors remains largely descriptive, offering limited precision into how specific biomarker values or physiologic thresholds influence susceptibility. We aimed to synthesize knowledge from machine learning models trained across multiple health systems to identify generalizable, value-specific risk drivers and biomarker interactions contributing to AKI risk. Methods: We analyzed electronic health records (EHRs) from 785,497 adult inpatients between 2010 and 2019 across nine U.S. academic medical centers within PCORnet. Interpretable gradient boosting machine models were independently developed at each health system to quantify predictor-outcome associations. Meta-regression was applied to integrate these site-level results, characterize nonlinear value-risk relationships, and identify bivariate interactions between predictors. Results: Meta-analysis revealed consistent, value-specific risk drivers across health systems. An increase in glucose from 100 mg/dL to 140 mg/dL was associated with a 1.46-fold higher risk of AKI. Chloride and anion gap also demonstrated elevated AKI risk with risk increases overlapping portions of their reference ranges, with anion gap showing a 1.14-fold increase across 4-12 mmol/L and chloride a 1.28-fold increase across 96-100 mEq/L. Electrolytes including potassium, calcium, and sodium showed quadratic associations with AKI risk. Bivariate meta-regression identified interactions between key predictors, highlighting pathways that jointly modulate AKI risk. Conclusion: This cross-system meta-analysis synthesizes machine learning-derived evidence into clinically interpretable knowledge, revealing how specific biomarker ranges and interactions modulate AKI risk. By moving beyond surface-level associations to quantitative, generalizable physiologic thresholds, these findings provide actionable insights to enhance risk stratification and personalized prevention in hospital care.

Introduction: Kidney volume is associated with renal function, but conventional whole-organ measurements may miss regional changes in kidney substructures. We used magnetic resonance imaging (MRI) to test whether kidney substructure volumes and three-dimensional (3D) thickness phenotypes are associated with disease, adiposity, and incident outcomes. Methods: Automated abdominal MRI segmentations from 70,270 UK Biobank participants were used to quantify left and right kidney cortex, medulla, and parenchyma volumes and mesh-based thickness maps. Mass univariate regression generated statistical parametric maps linking regional thickness to anthropometric traits and disease (CKD, type-2 diabetes [T2D], hypertension). Bidirectional causal mediation analyses were performed using kidney substructure volumetric, thickness PCs and kidney adiposity. Longitudinal changes were assessed in 2,610 participants with repeat imaging. Cox proportional hazards models tested the associations between kidney volumes and principal component (PC) scores of thickness and incident CKD, T2D, hypertension, cardiovascular disease (CVD), and mortality. Results: CKD was associated with thinning of the parenchyma and most pronounced in the medulla (87.7% left, 72.8% right), whereas associations in the cortex were mixed. In contrast, T2D and hypertension were predominantly associated with increased thickness, most extensively in the cortex (T2D: 84.39% left, 96.35% right; hypertension: 94.8% left, 99.9% right). Age-disease interactions were associated with reduced thickness across all conditions. Smaller medulla volume and lower cortical thickness mediated the association between CKD and renal sinus fat. Kidney substructure volume was inversely associated with incident CKD across all substructures and both kidney sides (p<0.05), but positively associated with incident hypertension and mortality (p<0.05). Thickness PC scores also predicted outcomes independently of volume, with PC3 in the left cortex (HR 0.91 [0.84-0.98]), reflecting inferior pole/hilar thickness, associated with incident CKD. Conclusions: MRI-derived kidney substructure volumes and 3D thickness maps provide complementary, spatially-resolved markers of kidney morphology, that are mechanistically linked to renal adiposity and future disease risk.

Abstract Background. Enteric hyperoxaluria (EH) causes calcium oxalate kidney stones, oxalate nephropathy, and chronic kidney disease (CKD), and can progress to end-stage kidney disease. It occurs in Crohn's disease (CD), cystic fibrosis (CF), chronic pancreatitis, celiac disease, short bowel syndrome, and after bariatric surgery. Its prevalence in these populations has not been synthesized. Methods. PROSPERO CRD420261364424. PubMed and Embase were searched to 24 August 2026 for studies reporting 24-hour urinary oxalate. Prevalence was pooled using the Freeman-Tukey double arcsine transformation with a DerSimonian-Laird random-effects model; unweighted crude prevalence is also reported. Because heterogeneity was high, the narrative synthesis stratified by testing condition is the primary result. Prespecified subgroups addressed oxalate load before collection, diagnostic threshold, ileal resection, age, and urine collection format. Results. Forty-seven studies were included. In CD (17 studies, 471 patients; 204 with EH), crude prevalence was 43.3% and pooled prevalence 49.3% (95% CI 38.9-59.8; I^2 = 95.3%). With an oxalate load, prevalence was 64.7% (pooled 74.0%, 55.9-88.6) versus 38.6% without (pooled 39.1%, 28.7-50.0). Among CD patients, EH was more frequent with ileal resection (48.8% vs 31.7%; OR 1.62, 0.91-2.89) and with steatorrhea (62.5% vs 29.3%; OR 9.88, 3.81-25.61). In CF (7 studies, 348 patients; 179 with EH), pooled prevalence was 49.8% (40.5-59.1; I^2 = 91.9%). After bariatric surgery (15 studies, 849 patients; 474 with EH), pooled prevalence was 54.7% (45.4-63.9; I^2 = 96.7%). Conclusions. Roughly half of these patients have EH, but the proportion depends heavily on whether an oxalate load precedes urine collection (39% unprovoked vs 65%-74% provoked); because most studies do not state this condition, published prevalence estimates are not directly comparable. Ileal resection and steatorrhea identify those who should be screened.

Background Hepatitis E virus infection is associated with renal manifestations in selected clinical populations. Whether serologic evidence of previous exposure is associated with kidney dysfunction in the general population remains uncertain. Methods We conducted a cross-sectional analysis of six National Health and Nutrition Examination Survey cycles from 2009-2018 and August 2021-August 2023. Adults aged [&ge;]20 years with valid hepatitis E virus immunoglobulin G levels, serum creatinine levels, urinary albumin-to-creatinine ratios, and covariate data were included. The outcomes included a reduced estimated glomerular filtration rate (<60 mL/min/1.73 m2), albuminuria (albumin-to-creatinine ratio [&ge;]30 mg/g [3.39 mg/mmol]), and their composite. Survey-weighted logistic regression models were unadjusted, adjusted for age and sex, and additionally adjusted for demographic and clinical covariates. Results Among 30,428 adults, 2,911 were seropositive; the weighted seroprevalence was 8.29%. The seropositive participants were older than the seronegative participants were (weighted mean, 60.7 versus 46.5 years). Seropositivity was associated with all three binary outcomes in unadjusted analyses, but the estimates approached the null after adjustment for age and sex. The fully adjusted odds ratios were 0.99 (95% confidence interval, 0.85-1.16) for a reduced filtration rate, 1.05 (0.91-1.22) for albuminuria, and 1.05 (0.93-1.19) for composite kidney dysfunction. In a secondary analysis, seropositivity was associated with a 1.57 mL/min/1.73 m2 higher adjusted mean filtration rate (95% confidence interval, 0.71-2.43). Conclusions Hepatitis E virus immunoglobulin G seropositivity was not significantly associated with binary kidney outcomes after adjustment. Attenuation occurred principally after adjustment for age and sex. These findings do not establish the absence of an association and do not address kidney injury during active or persistent infection.

Certain glomerulopathies (GN) feature impaired protein homeostasis in the endoplasmic reticulum (ER) of podocytes. Protein misfolding causing ER stress activates the unfolded protein response (UPR), a protective signaling network. Mesencephalic astrocyte-derived neurotrophic factor (MANF) and ERdj3/DNAJB11 are ER chaperones that may be secreted from cells during the UPR. In rats with membranous nephropathy (MN) and focal segmental glomerulosclerosis (FSGS), secretion of MANF or ERdj3 from podocytes into urine identified glomerular ER stress/UPR activation. We address the biomarker potential of MANF and ERdj3 in human MN and FSGS. Glomerular gene expression of MANF and ERdj3 was increased in human MN and FSGS. Urinary MANF and ERdj3 were increased in proteinuric MN and FSGS compared to MN and FSGS in remission (low proteinuria), as well as other GNs, polycystic kidney disease, hypertension and healthy controls. In individuals with proteinuric MN or FSGS, amounts of urinary MANF and ERdj3 correlated weakly with proteinuria; correlation of MANF with ERdj3 was moderate. Males represented ~60% of persons in each group. eGFR in proteinuric MN and FSGS was >40 ml/min/1.73 m2. In MN, there were no significant differences in urinary MANF and ERdj3 between anti-PLA2R positive and negative individuals. In conclusion, proteinuric MN and FSGS show increased glomerular expression of MANF and ERdj3. High urinary levels of these ER chaperones correlate only weakly with proteinuria. In these GNs, urinary ER chaperones are thus non-invasive biomarkers of glomerular/podocyte ER stress. Such biomarkers may eventually be useful in identifying patients for therapies targeting ER protein misfolding.

Background IgA vasculitis (IgAV) is the most common systemic vasculitis in children, and its prognosis is largely determined by renal involvement (IgAV nephritis). No routine blood test identifies IgAV or stratifies the risk of nephritis, although aberrant O-glycosylation of the IgA1 hinge region is central to its pathogenesis. We developed a mass-spectrometry assay to profile IgA1 hinge O-glycoforms and define signatures of disease activity and renal involvement. Methods IgA was affinity-purified from 5 uL of plasma from 91 children (27 with acute IgAV, 26 in remission, and 38 age-matched healthy controls; 24 with and 29 without nephritis), trypsin-digested, and hinge-region O-glycopeptides were quantified by LC-MS. Sixty-nine glycoforms were normalized to a total-IgA1 tryptic peptide. Duplicate measurements showed good analytical repeatability, with a median coefficient of variation of 6%. Groups were compared using Mann-Whitney and Kruskal-Wallis tests (Benjamini-Hochberg FDR). Discrimination was assessed by ROC analysis and cross-validated logistic regression panels. Results Acute IgAV showed broad remodeling of the hinge glycoform profile (35 glycoforms differed with excellent discrimination (AUC 0.93-0.95) for the best ones), with an increase in low-sialylated, agalactosylated species and a decrease in complex sialylated species. The profile was normalized in remission (no glycoform differed from the controls). Two distinct renal patterns emerged: disease-associated glycoforms already altered without nephritis and renal-specific glycoforms altered only in nephritis (H2N2S1, H3N3S5, H3N4S4, and H4N4S3). A four-marker panel discriminated nephritis among IgAV children with a cross-validated AUC of 0.86 (IC95 % 0.75-0.94). Conclusions A single mass-spectrometry assay, from a small blood volume, captures an IgAV-associated IgA1 hinge O-glycoform signature that normalizes in remission, together with a distinct renal involvement associated signature. These findings identify candidate IgA1 O-glycoform signatures associated with IgAV activity and documented renal involvement. Prospective longitudinal studies are required to determine whether the renal-associated panel can predict subsequent nephritis.

Background: Chronic kidney disease (CKD) imposes persistent metabolic stress, yet whether metabolic organization can be preserved under sustained renal stress remains unclear. Essential trace elements support redox defense, mitochondrial function, and intermediary metabolism, and their homeostasis is disturbed in CKD; however, single-element supplementation has yielded heterogeneous results. We examined whether a defined multi-element formulation preserves metabolic resilience in CKD. Methods: In a randomized, double-blind, placebo-controlled trial, 80 maintenance dialysis patients received standard care alone (n = 40) or plus a trace element cocktail (TEX, 20 mL/day; n = 40). Longitudinal trajectories were analyzed with linear mixed-effects models; endpoint plasma metabolomics and fecal metagenomics were profiled in subsets. A 5/6 nephrectomy mouse model was used to quantify plasma tryptophan-pathway branches and renal spatial metabolism by MALDI imaging mass spectrometry. Results: TEX was well tolerated, with no treatment-related safety signal, and was associated with modestly more favorable creatinine and eGFR trajectories. Supplementation constrained, rather than erased, CKD-associated metabolic displacement (median |Cohen's d|, 0.25 versus 2.09 for disease effects), selectively realigning circulating metabolism toward the healthy state. The host kynurenine branch responded most strongly, whereas microbial indole metabolism and gut community structure changed little. Renal metabolic remodeling was region-specific, with preservation of selected tubular and antioxidant features. Conclusions: Trace element supplementation preserved metabolic resilience in CKD, limiting metabolic displacement without complete restoration. Preservation of metabolic organization may represent a complementary dimension of therapeutic response in CKD. Trial registration: International Traditional Medicine Clinical Trial Registry, ITMCTR2026000263 (registered 3 February 2026).

Introduction: Pediatric renal vein thrombosis is a rare but well-recognized form of venous thromboembolism. While long-term renal outcomes of neonatal cases are well-described, they are relatively unknown in cases affecting older children. Moreover, the ability of anticoagulation treatment to prevent these outcomes remains unknown. The objective of this study was to assess adverse long-term renal outcomes and determine if anticoagulation reduced their likelihood. Methods: Administrative data analysis utilizing the Pediatric Health Information System database. Renal vein thrombosis occurring in patients under 18 years were assessed. Cases involving tumor thrombus were excluded to focus the analysis only on thrombotic disease. Demographics, co-morbid conditions, anticoagulant therapies, and renal outcomes were assessed over a 9-year period. In sub-analyses, neonatal ([&le;]28 days) and non-neonatal renal vein thromboses were assessed to determine how their characteristics may differ. Results: 383 eligible renal vein thrombosis cases with 796 patient-years of follow-up were identified for analysis. 48.8% of the cases occurred in neonates. 25.3% of the cases occurred in children with pre-existing complex chronic conditions and 9.1% were associated with the onset of nephrotic syndrome. Mortality followed 15.1% of the cases, but causality cannot be assigned from administrative data. Most (80.2%) of the cases were treated with anticoagulation. Acute kidney injury occurred in 24% of cases, chronic kidney disease developed in 22.2%, hypertension in 26.9%, and proteinuria in 3.1%. Anticoagulation did not have a discernable effect on the likelihood of these long-term renal outcomes. Conclusion: Acute kidney injury, chronic kidney disease, and hypertension are prevalent in survivors of childhood renal vein thrombosis. Anticoagulation does not appear to reduce the incidence of long-term renal outcomes, but the low percentage of non-anticoagulated patients suggests treatment bias. Long-term kidney health surveillance is warranted in pediatric renal vein thrombosis survivors.

Vitamin D sterols, phosphorus binders and calcimimetics are used to treat chronic kidney disease mineral and bone disorder (CKD-MBD) in hemodialysis. With few randomized trials, providers may titrate agents differently reflecting equipoise and opportunities for clinical trials. We studied patients initiating in-center hemodialysis at Dialysis Clinic, Inc facilities from 2006-2015 and who remained on hemodialysis for [&ge;]90 days (n=23,549). Multinomial logit models assessed titration among users of each medication at the start of the month considering static and dynamic CKD-MBD laboratories. Similarly parameterized logistic models assessed treatment initiation. Differences across facilities were quantified as random effects and corresponding median odds ratios. We observed patterns of titration associated with CKD-MBD laboratories including albumin-corrected serum calcium (Ca), serum phosphorus and parathyroid hormone (PTH) and minimal impact of patient characteristics. Best fit models incorporated 3 months of lagged Ca and phosphorus values and linear splines for current Ca, phosphorus and PTH values. Absolute titration probabilities for vitamin D sterols and calcimimetics were influenced by all three CKD-MBD parameters, such that Ca and phosphorus values altered the threshold PTH at which escalation and de-escalation probabilities crossed. Median odds ratios indicated the greatest facility variation for vitamin D sterol titration. Providers titrate CKD-MBD medications based largely on the full CKD-MBD laboratory phenotype, including the recent serum Ca, phosphorus and PTH history. Facility variation suggests equipoise in titration of vitamin D sterols with opportunities for clinical trials.

ABSTRACT Importance: The prevalence of chronic kidney disease (CKD) is increasing, with aging being a major contributor. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) are well established therapies for CKD; however, adults aged 80 years or older have been underrepresented in previous large-scale trials. Consequently, evidence regarding effects of SGLT2i therapy in this cohort remains limited. Objective: To evaluate the association of SGLT2i initiation with mortality, kidney outcomes and cardiovascular outcomes among patients over 80 years of age and CKD. Design, Setting, Participants: This retrospective cohort study used data from TriNetX Research Network, a multicenter electronic health record database. To ensure comparable standard of care and SGLT2i eligibility, the period for the occurrence of the index event was restricted to January 1, 2021, until January 1, 2025. Propensity score matching was performed to balance comorbidities, laboratory parameters, concomitant medications, and frailty-associated factors between groups. Exposures: Initiation of SGLT2i therapy vs. non-use Main Outcomes and Measures: Outcome analysis focused on all-cause mortality, major adverse kidney events (MAKE) and major adverse cardiovascular events (MACE). Cox proportional hazards models were used to estimate hazard ratios with 95% confidence intervals; following propensity score matching, results were considered as adjusted hazard ratios (aHR). Results: After propensity score matching, 5,038 patients were included in each group. During two years of follow-up, SGLT2i initiation was associated with lower all-cause mortality (aHR 0.818; 95% CI 0.746 - 0.896, p<0.0001) and fewer MAKE events (aHR 0.779; 95% CI 0.0.715 - 0.850, p<0.0001). No significant difference in MACE was observed (aHR 1.007; 95%CI 0.938 - 1.082, p=0.84). Results were generally consistent across subgroups. Risk of acute kidney injury was higher in the SGLT2i group, while incident dialysis and end-stage renal disease were significantly reduced. Acute myocardial infarction and acute heart failure were increased in the SGLT2i group. Conclusion and Relevance: Regarding survival and kidney endpoints, even the oldest CKD patients seem to benefit from SGLT2i treatment, which was associated with reduced mortality as well as improved long-term renal outcomes. MACE showed no significant differences, while specific cardiac events were increased, reflecting possible safety concerns requiring further investigation in this specific age group.

Background: Genomic reassessment may reveal clinically relevant diagnoses in patients with young-onset kidney failure despite established clinical diagnostic labels. We evaluated this approach after excluding clinically apparent polycystic kidney disease (PKD). Methods: Among 1,139 patients receiving maintenance dialysis at participating Japanese facilities, 355 had initiated dialysis at age [&le;]50 years. After excluding 17 patients with clinically apparent PKD, 108 of 338 eligible patients underwent whole-genome sequencing through voluntary, nonrandom enrollment. Analysis included 465 nuclear candidate genes, mitochondrial DNA, and copy-number/structural variants. Clinically concordant diagnoses were adjudicated using integrated clinical and genetic evidence, with a separate pathogenic/likely pathogenic (P/LP)-supported subset. Results: Diagnoses were identified in 10/108 participants (9.3%; 95% confidence interval, 5.1-16.2), comprising seven renal and three systemic/metabolic diagnoses. Nine diagnoses were P/LP-supported (8.3%; 95% confidence interval, 4.4-15.1). The remaining diagnosis was phenotype-based clinical Dent disease associated with a CLCN5 variant of uncertain significance. Diagnoses occurred across diabetic kidney disease, nephrosclerosis, chronic glomerulonephritis, unknown-cause, and other clinical categories. In a post hoc analysis excluding three participants with low target coverage, the integrated and P/LP-supported proportions were 9/105 (8.6%) and 8/105 (7.6%). Six exploratory findings were excluded from both diagnostic numerators. Gitelman syndrome was included as a clinically manifest renal disorder, although its contribution to kidney failure remained uncertain. Conclusions: Integrated genomic assessment can uncover renal and systemic/metabolic diagnoses across conventional labels in young-onset kidney failure after exclusion of clinically apparent PKD. Nonrandom enrollment and variable sequencing coverage limit generalizability and interpretation of negative results.

Introduction: Autosomal-dominant tubulointerstitial kidney disease (ADTKD) is characterized by chronic kidney disease (CKD) with an average age of end-stage renal disease (ESRD) of approximately 45 years, bland urinary sediment, the absence of proteinuria and autosomal dominant inheritance. While several causative genes have been found, there remain families in whom no molecular diagnosis has been identified (ADTKD-NMD). Methods: We identified BICC1 truncating variants in several families with ADTKD-NMD in the Wake Forest Rare Inherited Kidney Disease Registry and then screened families in our database and other referred families for BICC1 truncating variants. We performed segregation analysis and characterized affected individuals for clinical and histopathologic phenotypes. We analyzed oligomer formation of BICC1 mutants with wild-type BICC1-, ANKS3- and ANKS6 proteins through co-immunoprecipitation and Western blotting, and we tested for posttranscriptional regulation of the BICC1 target mRNA, Dand5, in a Luciferase reporter assay. Results: We found 6 heterozygous truncating mutations in BICC1 segregating with the ADTKD phenotype in 8 independent pedigrees worldwide. Affected individuals developed kidney failure in the 6th to 7th decade of life that was characterized pathologically by tubular atrophy and interstitial fibrosis. The truncated gene products localized to cytoplasmic bodies and demonstrated various degrees of self-association or binding to the known interaction partners, ANKS3 and ANKS6. While the wild-type BICC1 gene product acts as a posttranscriptional repressor of target mRNAs, all truncation variants exhibited increased expression of substrate mRNA. Conclusions: Truncating variants in BICC1 are a novel cause of ADTKD, segregating with the disease phenotype and upregulating BICC1 target gene expression through a dominant-negative- or a gain-of-function mode of action.

Intracranial aneurysms (IA) and their rupture (subarachnoid haemorrhage, SAH) are a rare but serious complication of autosomal dominant polycystic kidney disease (ADPKD). Both genetic and environmental risk factors contribute to the pathogenesis of IA and SAH, but specific information on risk factors in the ADPKD population are limited and international clinical guidelines mainly recommend screening for ADPKD patients with a family history of IA or SAH. We assessed the associations of monogenic variants, polygenic risk, and clinical factors with the diagnosis of IA or SAH in 2,200 adult ADPKD patients from three cohorts: the Irish Kidney Gene Project (IKGP, n=475), FinnGen (n=826), and Genomics England (GEL, n=899). Polygenic risk scores (PRS) for IA, hypertension, and smoking intensity were derived from previously published GWAS summary statistics and additionally conditioned using mtCOJO to account for their genetic correlation. IA or SAH was diagnosed in 158 of 2,200 patients (7.2%; mean age at diagnosis 51.1 years). Female sex (HR 2.21, 95% CI 1.50-3.25, p=6.52x10^-5) and smoking (HR 2.06, 95% CI 1.43-2.96, p=9.49x10^-5) were associated with IA or SAH in univariate Cox proportional hazards models, while diabetes was protective (HR 0.39, 95% CI 0.22-0.70, p=1.37x10^-3). Monogenic variant status was not found to associate with increased risk of IA or SAH. Polygenic score for IA was associated with increased risk of IA or SAH, with a 1 standard deviation increase in PRS associated with a pooled hazard ratio (HR) of 1.30 (95% CI 1.09-1.57, p=4.66x10^-3), and the association of the conditioned IA PRS remained in multivariate Cox proportional hazards models accounting for clinical factors and monogenic variants (HR 1.26, 95% CI 1.03-1.55, p=0.02). The addition of polygenic scores added significant prognostic information for IA or SAH beyond clinical risk factors in FinnGen (p=3.61x10^-3) and GEL (p=8.84x10^-3) but not in IKGP, as assessed by the likelihood ratio test. Overall, our study shows that the strongest risk factors for IA or SAH in ADPKD patients are smoking history, female sex, and polygenic risk for IA. Hypertension was not associated with IA (HR 0.50, 95% CI 0.24-1.00, p=0.051), likely due to the high prevalence of hypertension in this population across cohorts (69.6-85.3%). While family history may be considered a proxy of genetic risk, this study suggests that family history itself may be of limited utility in discriminating individuals with ADPKD at risk of IA or SAH. Keywords: Intracranial Aneurysms, subarachnoid haemorrhage, Autosomal Dominant Polycystic Kidney Disease, Polygenic Risk Scores, Hypertension, Family History

Introduction: Red blood cell distribution width (RDW) and intra-individual variability (IIV) of biomarkers are different types of variation. Although their high levels are commonly associated with high mortality risks and poor clinical outcomes, the reason for this remains unclear. Methods: We explored the significance of this similarity using time-series data (from 143,475 samples) collected over a 9-year period from 1,216 patients on long-term hemodialysis. The IIV of each of the 22 blood-based biomarkers was assessed using the moving coefficient of variation (mCV). Non-linear longitudinal/temporal changes of the variables and their mutual relationships were analyzed using generalized additive (mixed) models. Results: RDW and all of the IIVs showed similar trends throughout the entire period of dialysis treatment: a rapid decrease after hemodialysis initiation followed by an increase that accelerated prior to death. The slopes of these downward and upward trends during each one-year period were statistically different from zero for RDW and the majority of the IIVs. Given the reported increase in the RDW and IIVs of several biomarkers in the pre-dialysis stages of chronic kidney disease, these shared changes might reflect alterations in homeostatic capacity. The RDW exhibited positive correlations with the mCVs of all 22 biomarkers (all p-values < 0.0009), suggesting that it represents dysregulation of the overall physiological system. Furthermore, the levels of the biomarkers showed a specific (nearly linear or U-shaped) relationship with the RDW, analogous to their reported relationship to all-cause mortality in the hemodialysis population. Conclusion: Increased RDW could serve as a marker of physiological dysregulation, and measurement of the RDW can be an effective tool for assessing the overall health status and identifying optimal ranges for various health indicators.

Autosomal dominant polycystic kidney disease (ADPKD) is characterized by cysts from different nephron segments, yet their origin remains inaccessible to in vivo imaging. Building on ex vivo studies that cyst sodium concentration ([Na+]) may reflect tubular origin, we developed a non-invasive 23Na magnetic resonance imaging (MRI) approach at 7 Tesla to phenotype ADPKD cysts in vivo based on cyst sodium. In nephrectomized ADPKD kidneys, cyst fluid [Na+] closely matched 23Na MRI signal intensities, revealing two distinct cyst phenotypes: serum-like high-[Na+] cysts and low-[Na+] cysts. High-[Na+] cysts expressed the proximal tubular marker sodium-glucose cotransporter-2, whereas low-[Na+] cysts expressed markers of distal tubules and collecting ducts. The vasopressin V2 receptor (V2R), the therapeutic target of tolvaptan, was detected exclusively in low-[Na+] cysts, linking sodium phenotype to therapeutic target expression. In vivo, 23Na MRI enabled classification of 2,299 cysts in 20 ADPKD patients. High-[Na+] cysts were 1.8-fold more frequent overall. Anatomical cyst localization did not predict sodium phenotype, underscoring the need for functional imaging rather than structural inference. Patients exhibited marked interindividual variation in cyst composition, with low-[Na+] cysts comprising 4.6% to 83.9% of all cysts. Given the exclusive expression of V2R in low-[Na+] cysts, this heterogeneity may influence disease progression and therapeutic responsiveness. These findings establish 23Na MRI as a non-invasive method to phenotype ADPKD cysts in vivo and provide a functional imaging approach with potential relevance for stratifying patients and guiding future therapeutic interventions.