Introduction: Immunocompromised kidney patients are at increased risk of prolonged SARS-CoV-2 infection and related complications. Preclinical evidence demonstrates a more potent inhibitory effect... Show moreIntroduction: Immunocompromised kidney patients are at increased risk of prolonged SARS-CoV-2 infection and related complications. Preclinical evidence demonstrates a more potent inhibitory effect of voclosporin on SARS-CoV-2 replication than tacrolimus in vitro. We investigated the potential antiviral effects of voclosporin on SARS-CoV-2 in immunocompromised patients.Methods: First, we conducted a prospective, randomized, open-label, proof-of-concept study in 20 kidney transplant recipients (KTRs) on tacrolimus-based immunosuppression who contracted mild to moderate SARS-CoV-2 infection. Patients were randomized to continue tacrolimus or switch to voclosporin. Second, we performed a post hoc analysis on SARS-CoV-2 infections in 216 patients with lupus nephritis (LN) on standard immunosuppression who were randomly exposed to voclosporin or placebo as part of a clinical trial that was conducted during the worldwide COVID-19 pandemic. Results: The primary end point was clearance of SARS-CoV-2 viral load and that did not differ between voclosporin-treated KTRs (median 12 days, interquartile range [IQR] 8-28) and tacrolimus-treated KTRs (median 12 days, IQR 4-16) nor was there a difference in clinical recovery. Pharmacokinetic analyses demonstrated that, when voclosporin trough levels were on-target, SARS-CoV-2 viral load dropped significantly more (DCt 7.7 [3.4-10.7]) compared to tacrolimus-treated KTRs (DCt 2.7 [2.0-4.3]; P 1/4 0.035). In voclosporin-exposed patients with LN, SARS-CoV-2 infection was detected in 6% (7/116) compared to 12% (12/100) in placebo-exposed patients (relative risk [RR] 1.4 [0.97-2.06]). Notably, no voclosporin-exposed patients with LN died from severe SARS-CoV-2 infection compared to 3% (3/100) in placebo-exposed patients (RR 2.2 [1.90-2.54]).Conclusion: This proof-of-concept study shows a potential positive risk-benefit profile for voclosporin in immunocompromised patients with SARS-CoV-2 infection. These results warrant further investigations on voclosporin to establish an equipoise between infection and maintenance immunosuppression. Show less
Introduction: Transplant clinicians may disagree on whether or not to accept a deceased donor kidney offer. We investigated the interobserver variability between transplant nephrologists regarding... Show moreIntroduction: Transplant clinicians may disagree on whether or not to accept a deceased donor kidney offer. We investigated the interobserver variability between transplant nephrologists regarding organ acceptance and whether the use of a prediction model impacted their decisions. Methods: We developed an observational online survey with 6 real-life cases of deceased donor kidneys offered to a waitlisted recipient. Per case, nephrologists were asked to estimate the risk of adverse outcome and whether they would accept the offer for this patient, or for a patient of their own choice, and how certain they felt. These questions were repeated after revealing the risk of adverse outcome, calcu-lated by a validated prediction model. Results: Sixty Dutch nephrologists completed the survey. The intraclass correlation coefficient of their estimated risk of adverse outcome was poor (0.20, 95% confidence interval [CI] 0.08-0.62). Interobserver agreement of the decision on whether or not to accept the kidney offer was also poor (Fleiss kappa 0.13, 95% CI 0.129-0.130). The acceptance rate before and after providing the outcome of the prediction model was significantly influenced in 2 of 6 cases. Acceptance rates varied considerably among transplant centers. Conclusion: In this study, the estimated risk of adverse outcome and subsequent decision to accept a suboptimal donor kidney varied greatly among transplant nephrologists. The use of a prediction model could influence this decision and may enhance nephrologists' certainty about their decision. Show less
Canney, M.; Induruwage, D.; Tang, M.L.; Pinho, N.A. de; Er, L.; Zhao, Y.S.; ... ; ISN INET-CKD Investigators 2023
Introduction: Despite recognized geographic and sex-based differences in hemoglobin in the general population, these factors are typically ignored in patients with chronic kidney disease (CKD) in... Show moreIntroduction: Despite recognized geographic and sex-based differences in hemoglobin in the general population, these factors are typically ignored in patients with chronic kidney disease (CKD) in whom a single therapeutic range for hemoglobin is recommended. We sought to compare the distribution of hemoglobin across international nondialysis CKD populations and evaluate predictors of hemoglobin.Methods: In this cross-sectional study, hemoglobin distribution was evaluated in each cohort overall and stratified by sex and estimated glomerular filtration rate (eGFR). Relationships between candidate predictors and hemoglobin were assessed from linear regression models in each cohort. Estimates were subsequently pooled in a random effects model.Results: A total of 58,613 participants from 21 adult cohorts (median eGFR range of 17-49 ml/min) and 3 pediatric cohorts (median eGFR range of 26-45 ml/min) were included with broad geographic representation. Hemoglobin values varied substantially among the cohorts, overall and within eGFR categories, with particularly low mean hemoglobin observed in women from Asian and African cohorts. Across the eGFR range, women had a lower hemoglobin compared to men, even at an eGFR of 15 ml/min (mean difference 5.3 g/l, 95% confidence interval [CI] 3.7-6.9). Lower eGFR, female sex, older age, lower body mass index, and diabetic kidney disease were all independent predictors of a lower hemoglobin value; however, this only explained a minority of variance (R-2 7%-44% across cohorts).Conclusion: There are substantial regional differences in hemoglobin distribution among individuals with CKD, and the majority of variance is unexplained by demographics, eGFR, or comorbidities. These findings call for a renewed interest in improving our understanding of hemoglobin determinants in specific CKD populations. Show less
Bouwmeester, R.N.; Duineveld, C.; Wijnsma, K.L.; Bemelman, F.J.; Heijden, J.W. van der; Wijk, J.A.E. van; ... ; Kar, N.C.A.J. van de 2022
Introduction: The introduction of eculizumab has improved the outcome in patients with atypical hemo-lytic uremic syndrome (aHUS). The optimal treatment strategy is debated. Here, we report the... Show moreIntroduction: The introduction of eculizumab has improved the outcome in patients with atypical hemo-lytic uremic syndrome (aHUS). The optimal treatment strategy is debated. Here, we report the results of the CUREiHUS study, a 4-year prospective, observational study monitoring unbiased eculizumab discontinuation in Dutch patients with aHUS after 3 months of therapy. Methods: All pediatric and adult patients with aHUS in native kidneys and a first-time eculizumab treat-ment were evaluated. In addition, an extensive cost-consequence analysis was conducted. Results: A total of 21 patients were included in the study from January 2016 to October 2020. In 17 patients (81%), a complement genetic variant or antibodies against factor H were identified. All patients showed full recovery of hematological thrombotic microangiopathy (TMA) parameters after the start of eculizumab. A renal response was noted in 18 patients. After a median treatment duration of 13.6 weeks (range 2.1-43.9), eculizumab was withdrawn in all patients. During follow-up (80.7 weeks [0.0-236.9]), relapses occurred in 4 patients. Median time to first relapse was 19.5 (14.3-53.6) weeks. Eculizumab was reinitiated within 24 hours in all relapsing patients. At last follow-up, there were no chronic sequelae, i.e., no clinically relevant increase in serum creatinine (sCr), proteinuria, and/or hypertension in relapsing patients. The low sample size and event rate did not allow to determine predictors of relapse. However, relapses only occurred in patients with a likely pathogenic variant. The cost-effectiveness analysis revealed that the total medical expenses of our population were only 30% of the fictive expenses that would have been made when patients received eculizumab every fortnight. Conclusion: It is safe and cost-effective to discontinue eculizumab after 3 months of therapy in patients with aHUS in native kidneys. Larger data registries are needed to determine factors associated with suboptimal kidney function recovery during eculizumab treatment, factors to predict relapses, and long-term outcomes of eculizumab discontinuation. Show less
Ramspek, C.L.; Boekee, R.; Evans, M.; Heimburger, O.; Snead, C.M.; Caskey, F.J.; ... ; EQUAL Study Investigators 2022
Introduction: Predicting the timing and occurrence of kidney replacement therapy (KRT), cardiovascular events, and death among patients with advanced chronic kidney disease (CKD) is clinically... Show moreIntroduction: Predicting the timing and occurrence of kidney replacement therapy (KRT), cardiovascular events, and death among patients with advanced chronic kidney disease (CKD) is clinically useful and relevant. We aimed to externally validate a recently developed CKD G4thorn risk calculator for these outcomes and to assess its potential clinical impact in guiding vascular access placement.Methods: We included 1517 patients from the European Quality (EQUAL) study, a European multicentre prospective cohort study of nephrology-referred advanced CKD patients aged $65 years. Model performance was assessed based on discrimination and calibration. Potential clinical utility for timing of referral for vascular access placement was studied with diagnostic measures and decision curve analysis (DCA).Results: The model showed a good discrimination for KRT and "death after KRT," with 2-year concordance (C) statistics of 0.74 and 0.76, respectively. Discrimination for cardiovascular events (2-year C-statistic: 0.70) and overall death (2-year C-statistic: 0.61) was poorer. Calibration was fairly accurate. Decision curves illustrated that using the model to guide vascular access referral would generally lead to less unused arteriovenous fistulas (AVFs) than following estimated glomerular filtration rate (eGFR) thresholds.Conclusion: This study shows moderate to good predictive performance of the model in an older cohort of nephrology-referred patients with advanced CKD. Using the model to guide referral for vascular access placement has potential in combating unnecessary vascular surgeries. Show less
Introduction: Lupus nephritis (LN) class III or IV is strongly related to patient mortality and morbidity. The interobserver agreement of endocapillary hypercellularity by routine light microscopy,... Show moreIntroduction: Lupus nephritis (LN) class III or IV is strongly related to patient mortality and morbidity. The interobserver agreement of endocapillary hypercellularity by routine light microscopy, one of the most important lesions determining whether class III or IV is present, is moderate. In IgA nephropathy (IgAN), the presence of glomerular CD68+ cells was found to be a good surrogate marker for endocapillary hypercellularity. We investigated whether the presence of glomerular CD68+ cells could serve as a surrogate marker for endocapillary hypercellularity as well in LN.Methods: A total of 92 LN biopsies were scored for the number of glomerular CD68+ cells using CD68 staining, including endocapillary hypercellularity and the activity index (AI). A new AI was calculated in which CD68+ cells replaced endocapillary hypercellularity. Clinical parameters were obtained from time of biopsy, 1 year after, and 2 years after.Results: The number of glomerular CD68+ cells significantly correlated with endocapillary hypercellularity. A cutoff value of 7 for the maximum number of CD68+ cells within 1 glomerulus in a biopsy yielded a sensitivity of 88% and a specificity of 67% for the presence of endocapillary hypercellularity. Both endocapillary hypercellularity and CD68+ cells correlated with renal function during follow-up. The current and the new AI correlated equally well with the clinical outcome.Conclusion: In LN, CD68+cells can be used as a surrogate marker for endocapillary hypercellularity. Show less
Introduction: In 2020, a working group of 13 renal pathologists published consensus definitions for 47 individual glomerular lesions found on light microscopy (LM) and 47 glomerular lesions and 9... Show moreIntroduction: In 2020, a working group of 13 renal pathologists published consensus definitions for 47 individual glomerular lesions found on light microscopy (LM) and 47 glomerular lesions and 9 normal structures found on electron microscopy (EM).Methods: To test the impact of these definitions on identification of these lesions and structures, 2 surveys were circulated to all members of the Renal Pathology Society (RPS), each having 32 images (19 LM, 13 EM) and accompanying questions with 5 multiple-choice answers, one being the consensus choice of the working group. The first survey (survey 1 [S1]), answered by 297 RPS members, was sent in September 2020, before publication of the consensus definitions. The second (survey 2 (S2]), with images of the same lesions and structures (but not the same images) and the same questions and multiple choices in different order, was sent in April 2020, 5 months after the publication of the definitions.Results: S2 was taken by 181 RPS members; 64% also took 51 and 61% reported having read the definitions paper (def. paper). Mean agreement with the consensus answers increased modestly between the 2 surveys (65.2% vs. 72.0%, P = 0.097); the increase was greater and significant when only respondents to S2 who read the def. paper were considered (65.2% vs. 74.8%, P = 0.026). Furthermore, in S2 agreement with consensus answers was greater among respondents who read this paper versus those who did not (66.9% vs. 74.8%, P < 0.0001).Conclusions: Publication of the consensus definitions modestly improved interobserver agreement in identification of glomerular lesions. Show less
Dirikgil, E.; Jonker, J.T.; Tas, S.W.; Verburgh, C.A.; Soonawala, D.; Hak, A.E.; ... ; Arthritis Res Collaboration Hub AR 2021
Introduction: Managing complex and rare systemic autoimmune diseases such as antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) can be challenging and is often accompanied by... Show moreIntroduction: Managing complex and rare systemic autoimmune diseases such as antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) can be challenging and is often accompanied by undesirable variations in clinical practice. Adequate understanding of clinical practice can help identify essential issues to improve the care for AAV patients. Therefore, we studied the real-life management and outcomes of AAV patients in the Netherlands.Methods: In this cohort study, we investigated clinical practice in university and nonuniversity teaching hospitals with respect to patients with a clinical diagnosis of AAV. We retrospectively collected clinical data encompassing clinical variables, medication details, and outcome parameters.Results: Data of 230 AAV patients were collected in 9 Dutch hospitals. Of these, 167 patients (73%) were diagnosed with granulomatosis with polyangiitis, 54 (24%) with microscopic polyangiitis and 9 (4%) with eosinophilic granulomatosis with polyangiitis. One hundred sixty-six patients (72%) had generalized disease. The median year of diagnosis was 2013 (range 1987-2018). Besides steroids, oral cyclophosphamide was the most used drug (50%) for induction therapy and azathioprine (68%) for maintenance therapy. Adverse outcomes were major infections in 35%, major relapses in 23%, malignancy in 10%, major cardiovascular events in 8%, and end-stage renal disease in 7%.Conclusion: Oral cyclophosphamide was the most frequently used induction therapy, azathioprine for maintenance therapy; over time, the use of rituximab is increasingly employed. Major infection and relapses are the most prevalent adverse outcomes. This audit resulted in important indicators for treatment of AAV patients that can be implemented for future, national audits to improve the outcomes of AAV patients. Show less
Lest, N.A. van de; Bakker, A.E.; Dijkstra, K.L.; Zandbergen, M.; Heemskerk, S.A.C.; Wolterbeek, R.; ... ; Scharpfenecker, M. 2021
Introduction: The podocyte is thought to be the mainly affected cell type in focal segmental glomerulosclerosis (FSGS). However, recent studies have also indicated a role for glomerular endothelial... Show moreIntroduction: The podocyte is thought to be the mainly affected cell type in focal segmental glomerulosclerosis (FSGS). However, recent studies have also indicated a role for glomerular endothelial cells and podocyte-endothelial crosstalk in FSGS development. An experimental model for podocyte injury showed that increased endothelin-1 (ET-1) signaling between podocytes and endothelial cells induces endothelial oxidative stress and subsequent podocyte loss. In the current study, we investigated endothelial endothelin receptor A (ETAR) expression in patients with FSGS and its association with podocyte injury and glomerular oxidative stress.Methods: We selected 39 biopsy samples of patients with FSGS and 8 healthy control subjects, and stained them for ETAR, nephrin and 8-oxo-guanine, a DNA lesion caused by oxidative damage. Glomeruli with ETAR-positive endothelium and with nephrin loss were scored, and the 8-oxo-guanine-positive glomerular area was measured.Results: The mean percentage of glomeruli with ETAR-positive endothelial cells in patients with FSGS was higher compared to that in healthy control subjects (52% vs. 7%; P < 0.001). The presence of glomerular ETAR-positive endothelium was strongly associated with nephrin loss both on the biopsy level (rho = 0.47; P < 0.01), as on the level of individual glomeruli (odds ratio = 2.0; P < 0.001). Moreover, glomeruli with ETAR-positive endothelium showed more 8-oxo-guanine-positive staining (1.9% vs. 2.4%; P = 0.037). Finally, 8-oxo-guanine positivity in glomeruli was associated with increased levels of proteinuria.Conclusion: Taking together our findings, we show that ETAR is increased in glomerular endothelial cells of patients with FSGS and associated with podocyte damage and glomerular oxidative stress. These findings support the hypothesis that ET-1 signaling in glomerular endothelial cells contributes to disease development in patients with FSGS. Show less
Introduction: Preservation of peritoneal function is essential in long-term peritoneal dialysis. Biocompatible dialysis solutions might prevent or postpone the membrane alteration resulting in... Show moreIntroduction: Preservation of peritoneal function is essential in long-term peritoneal dialysis. Biocompatible dialysis solutions might prevent or postpone the membrane alteration resulting in ultrafiltration failure and consecutive morbidity and mortality.Methods: We conducted an observational cohort study in which we made a longitudinal comparison between the course of peritoneal solute and fluid transport during treatment with conventional and biocompatible solutions. Therefore, prospectively collected peritoneal transport data from the yearly standard peritoneal permeability analysis were analyzed in 251 incident patients treated between 1994 and censoring in 2016. Fluid transport included small pore and free water transport. Solute transport was assessed by creatinine mass transfer area coefficient and glucose absorption. Linear mixed models including change point analyses were performed. Interaction with peritonitis was examined.Results: One hundred thirty-five patients received conventional and 116 biocompatible solutions. Sixtyseven percent (conventional) and 64% (biocompatible) of these underwent minimally three transport measurements. Initially, biocompatible fluids showed higher small solute transport and lower ultrafiltration than conventional fluids up to 3 years. Thereafter, conventional fluids showed an increase in small solute transport (+2.7 ml/min per year; 95% confidence interval [CI]: 0.9 to 4.5) and a decrease of free water transport (-28.0 ml/min per year; 95% CI: -60.4 to 4.4). These were minor or absent in biocompatible treatment. Peritonitis induced a decrease of transcapillary ultrafiltration after 2 years on dialysis with conventional solutions (-291 ml/min per year; 95% CI: -550 to -32) while this was absent in biocompatible treatment.Conclusion: Despite a higher initial solute transport with biocompatible solutions, these have less influence on functional long-term peritoneal alterations than conventional solutions. (C) 2020 International Society of Nephrology. Published by Elsevier Inc. Show less
Losekoot, M.; Meijer, E.; Hagen, E.C.; Belostotsky, V.; Borst, M. de; Tholens, A.; ... ; Peters, D.J.M. 2020
INTRODUCTION: Maturation failure of radiocephalic arteriovenous fistulas (RCAVF) is a significant clinical issue. Vascular inflammation after AVF surgery is associated with non-maturation.OBJECTIVE... Show moreINTRODUCTION: Maturation failure of radiocephalic arteriovenous fistulas (RCAVF) is a significant clinical issue. Vascular inflammation after AVF surgery is associated with non-maturation.OBJECTIVE: To evaluate whether liposomal prednisolone improves RCAVF maturation in end-stage renal disease (ESRD) patients.DESIGN: The LIPMAT-study was a multi-center, double-blind, 1:1 randomized, placebo-controlled trial.MATERIALS AND METHODS: Subjects were enrolled after RCAVF creation and treated with placebo or 150 mg of liposomal prednisolone at days 1 and 15 after AVF surgery. The primary end point was the juxta-anastomotic diameter of the cephalic vein at 6 weeks after surgery. Secondary end points were the diameter of the cephalic vein, brachial and radial artery at 6 weeks and 3 months after surgery as well as AVF flow and functional use for hemodialysis. Adverse events were compared to assess safety.RESULTS: 29 subjects were included of which 13 received placebo and 16 received liposomal prednisolone. The juxta-anastomitic cephalic vein diameter at 6 weeks was 3.9 mm (95% confidence interval 2.7 – 5.8 mm) in the placebo group and 3.7 mm (95% confidence interval 3.0 – 5.3 mm) in the liposomal prednisolone group (p=0.88). No significant differences in secondary end point parameters were observed. Treatment of end-stage renal disease patients with liposomal prednisolone was not associated with significant side effects.CONCLUSION: Liposomal prednisolone treatment of ESRD patients was safe, but did not result in enhanced RCAVF maturation. Show less
Introduction: Autosomal dominant polycystic kidney disease (ADPKD) is characterized by progressive cystformation and variable renal function decline that frequently leads to end-stage renal failure... Show moreIntroduction: Autosomal dominant polycystic kidney disease (ADPKD) is characterized by progressive cystformation and variable renal function decline that frequently leads to end-stage renal failure. With theadvent of renoprotective treatment, there is renewed interest in noninvasive biomarkers to help identifypatients at risk of rapid disease progression at early stages. Urinary tissue inhibitor of metalloproteinases-2 (TIMP-2) and insulin-like growth factor–binding protein 7 (IGFBP7) have been validated as early markersof acute kidney injury. Because these markers are associated with tubular damage, we studied the per-formance of both markers in a cohort with chronic tubular pathology. We investigated whether thesebiomarkers may be useful to evaluate disease severity in ADPKD.Methods: In a cross-sectional analysis, we measured TIMP-2 and IGFBP7 in stored spot urine samples of pa-tients with ADPKD with various stages of chronic kidney disease (CKD) and healthy controls by enzyme-linkedimmunosorbent assay. Renal function was estimated using the CKD–Epidemiology Collaboration equation.Patients were stratified according to the Kidney Disease Outcomes Quality Initiative classification for CKD. In asubset of patients, total kidney volume (TKV; using magnetic resonance imaging [MRI]) was measured.Results: In 296 patients with ADPKD (45.5 11.5 years, 51.0% female, serum creatinine 106 [85–147] mmol/l),urine levels of TIMP-2 and IGFBP7 were not increased or tended to be lower as compared with 71 healthycontrols (46.5 18.5 years, 72.6% female). The levels did not differ across CKD stages, which remained so aftercorrecting for urine creatinine or osmolality, and for age, sex, and urine protein in multivariable analyses.Conclusions: Urinary levels of TIMP-2 and IGFBP7 were not higher in patients with ADPKD, and did notcorrelate with disease severity. Show less
