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ZusammenfassungEpidemiologische Untersuchungen zeigen, dass etwa 2–3 % aller Österreicher*innen einen Diabetes mellitus mit Nierenbeteiligung aufweisen. Dies betrifft somit in Österreich etwa 250.000 Menschen. Das Risiko des Auftretens und Fortschreitens der diabetischen Nierenerkrankung kann durch Lebensstilinterventionen und Optimierung des arteriellen Blutdrucks, Blutzuckers und spezielle Medikamentenklassen vermindert werden. In diesem gemeinsamen Artikel der Österreichischen Gesellschaften für Nephrologie und Diabetologie werden die entsprechende Diagnostik und therapeutische Strategien bei diabetischer Nierenerkrankung vorgeschlagen.

Patients with end-stage kidney disease (ESKD) frequently develop left ventricular hypertrophy (LVH), which is associated with an exceptionally high risk of cardiovascular events and mortality. This review focuses on interventional studies that modify levels of fibroblast growth factor 23 (FGF23) and examine effects on myocardial hypertrophy, cardiovascular events and mortality.Quantitative evaluations of trials of calcimimetics found no effects on cardiovascular events and cardiovascular and all-cause mortality when compared with placebo. However, a recent randomized, controlled trial of etelcalcetide versus alfacalcidol showed that etelcalcetide effectively inhibited the progression of LVH in comparison to vitamin D in patients on haemodialysis after 1 year of treatment. Prior to that, oral calcimimetic treatment has already been shown to reduce left ventricular mass in patients on haemodialysis, whereas treatment with active vitamin D or mineralocorticoids was ineffective in patients with ESKD.Data from a recent trial of etelcalcetide on LVH suggest that FGF23 may be a possible therapeutic target for cardiac risk reduction in patients on haemodialysis. If these findings are confirmed by further research, it might be speculated that a treatment shift from active vitamin D towards FGF23-lowering therapy may occur in patients on haemodialysis.

International audience; OBJECTIVE: To identify and critically appraise risk prediction models for living donor solid organ transplant counselling.STUDY DESIGN AND SETTING: We systematically reviewed articles describing the development or validation of prognostic risk prediction models about living donor solid organ (kidney and liver) transplantation indexed in Medline until April 4(th) 2021. Models were eligible if intended to predict, at transplant counselling, any outcome occurring after transplantation or donation in recipients or donors. Duplicate study selection, data extraction, assessment for risk of bias and quality of reporting was done using the CHARMS checklist, PRISMA recommendations, PROBAST tool, and TRIPOD Statement.RESULTS: We screened 4691 titles and included 49 studies describing 68 models (35 kidney, 33 liver transplantation). We identified 49 new risk prediction models and 19 external validations of existing models. Most models predicted recipients outcomes (n=38, 75%), e.g., kidney graft loss (29%), or mortality of liver transplant recipients (55%). Many new models (n= 46, 94%) and external validations (n=17, 89%) had a high risk of bias because of methodological weaknesses. The quality of reporting was generally poor.CONCLUSION: We advise against applying poorly developed, reported or validated prediction models. Future studies could validate or update the few identified methodologically appropriate models.

Introduction Globally, there are more women with chronic kidney disease (CKD), yet they comprise only 40% of patients receiving kidney replacement therapy by dialysis. We aimed to describe the perspectives of nephrologists on gender disparities in access to care and outcomes in CKD and dialysis. Methods We conducted semi-structured interviews with 51 nephrologists (28, 55% women) from 22 countries from October-2019 to April-2020. Transcripts were analysed thematically. Results We identified six themes. Related to women were primary commitment to caregiving (with subthemes of coordinating care, taking charge of health management, deprioritising own health, centrality of family in decision-making); vigilance and self-reliance (diligence and conscientiousness, stoicism and tolerating symptoms, avoiding burden on family, isolation and coping alone); and stereotyping, stigma and judgement (body image, dismissed as anxiety, shame and embarrassment, weakness and frailty). Related to men was protecting masculinity (safeguarding the provider role, clinging to control, self-regard and entitled). Decisional power and ownership included men’s dominance in decision-making and women’s analytical approach in treatment decisions. Inequities compounded by social disadvantage (financial and transport barriers, without social security, limited literacy, entrenched discrimination, vulnerability) were barriers to care for women, particularly in socioeconomically disadvantaged communities. Conclusion Nephrologists perceived that women with CKD faced many challenges in accessing care related to social norms and roles of caregiving responsibilities, disempowerment, lack of support, stereotyping by clinicians, and entrenched social and economic disadvantage. Addressing power differences, challenging systemic patriarchy, and managing unconscious bias may help to improve equitable care and outcomes for all people with CKD.

ImportanceKidney transplant is considered beneficial in terms of survival compared with continued dialysis for patients with kidney failure. However, randomized clinical trials are infeasible, and available evidence from cohort studies is at high risk of bias.ObjectiveTo compare restricted mean survival times (RMSTs) between patients who underwent transplant and patients continuing dialysis across transplant candidate ages and depending on waiting time, applying target trial emulation methods.Design, Setting, and ParticipantsIn this retrospective cohort study, patients aged 18 years or older appearing on the wait list for their first single-organ deceased donor kidney transplant between January 1, 2000, and December 31, 2018, in Austria were evaluated. Available data were obtained from the Austrian Dialysis and Transplant Registry and Eurotransplant and included repeated updates on wait-listing status and relevant covariates. Data were analyzed between August 1, 2019, and December 23, 2021.ExposuresA target trial was emulated in which patients were randomized to either receive the transplant immediately (treatment group) or to continue dialysis and never receive a transplant (control group) at each time an organ became available.Main Outcomes and MeasuresThe primary outcome was time from transplant allocation to death. Effect sizes in terms of RMSTs were obtained using a sequential Cox approach.ResultsAmong the 4445 included patients (2974 men [66.9%]; mean [SD] age, 52.2 [13.2] years), transplant was associated with increased survival time across all considered ages compared with continuing dialysis and remaining on the wait list within a 10-year follow-up. The estimated RMST differences were 0.57 years (95% CI, –0.14 to 1.84 years) at age 20 years, 3.01 years (95% CI, 2.50 to 3.54 years) at age 60 years, and 2.48 years (95% CI, 1.88 to 3.04 years) at age 70 years. The survival benefit for patients who underwent transplant across ages was independent of waiting time.Conclusions and RelevanceThe findings of this study suggest that kidney transplant prolongs the survival time of persons with kidney failure across all candidate ages and waiting times.

Health care claims databases maintained by social insurance institutions provide rich and sometimes easily accessible data sources for epidemiological research. Interpreting the registered claims, for example, drug prescriptions, as proxies for the condition of interest, for example, diabetes, they allow for nationwide prevalence estimation. We illustrate a more subtle use of health care claims data in estimating the stage-specific prevalence of chronic kidney disease in the Austrian population with diabetes. The main difficulty was that information on the type of disease (chronic or acute) and information on the stage of disease were only available for small, almost disjoint subsets of the health care claims data. Using high-dimensional regression models, we could combine the information and provide nationwide estimates of the stage-specific prevalence of diabetic chronic kidney disease. Validating our estimates by comparing to other studies, we found the level of agreement satisfying.

Response to SARS-CoV-2-vaccines in kidney-transplant recipients (KTR) is severely reduced. Heterologous3rd vaccination combining mRNA and vector vaccines did not increase seroconversion at 4 weeks after vaccination, but evolution of antibody levels beyond the first month remains unknown. We have recently completed a randomized-controlled trial on heterologous (Ad26COVS1) vs. homologous (BNT162b2 or mRNA-1273) 3rd vaccination in 201 KTR not developing SARS-CoV-2-spike-protein antibodies following two doses of mRNA vaccine (EurdraCT: 2021-002927-39). Here, we report seroconversion at the second follow-up at 3 months after the 3rd vaccination (prespecified secondary endpoint). In addition, higher cut-off levels associated with neutralizing capacity and protective immunity were applied (i.e., > 15, > 100, > 141, and > 264 BAU/ml). A total of 169 patients were available for the 3-month follow-up. Overall, seroconversion at 3 months was similar between both groups (45 vs. 50% for mRNA and the vector group, respectively; p = 0.539). However, when applying higher cut-off levels, a significantly larger number of individuals in the vector group reached antibody levels > 141 and > 264 BAU/ml at the 3-month follow-up (141 BAU/ml: 4 vs. 15%, p = 0.009 and 264 BAU/ml: 1 vs. 10%, p = 0.018 for mRNA vs. the vector vaccine group, respectively). In line, antibody levels in seroconverted patients further increased from month 1 to month 3 in the vector group while remaining unchanged in the mRNA group (median increase: mRNA = 1.35 U/ml and vector = 27.6 U/ml, p = 0.004). Despite a similar overall seroconversion rate at 3 months following 3rd vaccination in KTR, a heterologous 3rd booster vaccination with Ad26COVS1 resulted in significantly higher antibody levels in responders.

SARS-CoV-2 gains cell entry via angiotensin-converting enzyme (ACE) 2, a membrane-bound enzyme of the “alternative” (alt) renin-angiotensin system (RAS). ACE2 counteracts angiotensin II by converting it to potentially protective angiotensin 1–7. Using mass spectrometry, we assessed key metabolites of the classical RAS (angiotensins I–II) and alt-RAS (angiotensins 1–7 and 1–5) pathways as well as ACE and ACE2 concentrations in 159 patients hospitalized with COVID-19, stratified by disease severity (severe, n = 76; non-severe: n = 83). Plasma renin activity (PRA-S) was calculated as the sum of RAS metabolites. We estimated ACE activity using the angiotensin II:I ratio (ACE-S) and estimated systemic alt-RAS activation using the ratio of alt-RAS axis metabolites to PRA-S (ALT-S). We applied mixed linear models to assess how PRA-S and ACE/ACE2 concentrations affected ALT-S, ACE-S, and angiotensins II and 1-7. Median angiotensin I and II levels were higher with severe versus non-severe COVID-19 (angiotensin I: 86 versus 30 pmol/L, p p p = 0.251; angiotensin II: 76 versus 99 pmol/L, p = 0.833). ALT-S in severe COVID-19 increased with time (days 1–6: 0.12; days 11–16: 0.22) and correlated with ACE2 concentration (r = 0.831). ACE-S was lower in severe versus non-severe COVID-19 (1.6 versus 2.6; p

BackgroundRepeated vaccination against SARS-CoV-2 increases serological response in kidney transplant recipients (KTR) with high interindividual variability. No decision support tool exists to predict SARS-CoV-2 vaccination response in KTR.MethodsWe developed, internally and externally validated five different multivariable prediction models of serological response after the third and fourth vaccine dose against SARS-CoV-2 in KTR. Using 27 candidate predictor variables, we applied statistical and machine learning approaches including logistic regression (LR), LASSO-regularized LR, random forest, and gradient boosted regression trees. For development and internal validation, data from 585 vaccinations were used. External validation was performed in four independent, international validation datasets comprising 191, 184, 254, and 323 vaccinations, respectively.FindingsLASSO-regularized LR performed on the whole development dataset yielded a 23- and 11- variable model, respectively. External validation showed AUC-ROC of 0.855, 0.749, 0.828, and 0.787 for the sparser 11-variable model, yielding an overall performance 0.819.InterpretationAn 11-variable LASSO-regularized LR model predicts vaccination response in KTR with good overall accuracy. Implemented as an online tool, it can guide decisions when choosing between different immunization strategies to improve protection against COVID-19 in KTR.

ZusammenfassungNierentransplantierte Patienten stellen während der COVID-19(„coronavirus disease 2019“)-Pandemie eine spezielle Risikogruppe dar. Dies liegt sowohl an den häufig bestehenden Komorbiditäten als auch an der therapeutischen Immunsuppression. Letzterer kommt auch angesichts der stark zu Morbidität und Mortalität beitragenden Hyperinflammation eine komplexe Rolle zu. Bislang publizierte Fallserien zeigen eine hohe Hospitalisierungsrate und eine Mortalität zwischen 13 und 23 % in dieser Population. Die klinische Symptomatik sowie bislang etablierte Risikofaktoren scheinen jenen der Allgemeinbevölkerung zu ähneln. Eine heikle Frage in der Behandlung von an COVID-19 erkrankten Nierentransplantierten ist der Umgang mit der Immunsuppression, welche gemäß aktuellen Empfehlungen stufenweise und in Abhängigkeit vom klinischen Verlauf reduziert werden sollte. Auf der Suche nach wirksamen Therapien gegen SARS-CoV‑2 („severe acute respiratory syndrome coronavirus 2“) wurden zahlreiche in anderen Indikationen etablierte antivirale und antiinflammatorische Substanzen untersucht, wobei bislang nur für die Therapie mit Dexamethason bei Patienten mit Sauerstoffbedarf eine überzeugende Evidenz zu bestehen scheint. Zahllose Studien zu teils auch neuentwickelten Therapien laufen derzeit.

Patient-reported outcomes (PROs) that assess individuals' perceptions of life participation, medication adherence, disease symptoms, and therapy side effects are extremely relevant in the context of kidney transplantation. All PROs are potentially suitable as primary or secondary endpoints in interventional trials that aim to improve outcomes for transplant recipients. Using PRO measures (PROMs) in clinical trials facilitates assessment of the patient's perspective of their health, but few measures have been developed and evaluated in kidney transplant recipients; robust methodologies, which use validated instruments and established frameworks for reporting, are essential. Establishing a core PROM for life participation in kidney transplant recipients is a critically important need, which is being developed and validated by the Standardized Outcomes in Nephrology (SONG)-Tx Initiative. Measures involving electronic medication packaging and smart technologies are gaining traction for monitoring adherence, and could provide more robust information than questionnaires, interviews, and scales. This article summarizes information on PROs and PROMs that was included in a Broad Scientific Advice request on clinical trial design and endpoints in kidney transplantation. This request was submitted to the European Medicines Agency (EMA) by the European Society for Organ Transplantation in 2016. Following modifications, the EMA provided its recommendations in late 2020. ispartof: TRANSPLANT INTERNATIONAL vol:35 ispartof: location:Switzerland status: published

BACKGROUND AND AIMS The genetics of kidney function has been extensively studied, but since these analyses have been done mostly in populations with normal or mildly impaired kidney function, it is still unknown whether variants linked to kidney function also translate into genetic susceptibility for kidney failure. The primary aim of this study was to investigate the genetic background of kidney failure. METHOD We performed a meta-analysis of kidney failure genome-wide association studies, using kidney transplant recipients as cases (n = 6942) and donors as controls (n = 4788). Secondary disease-specific analyses were performed for kidney failure due to diabetes, IgA nephropathy, glomerulonephritis or polycystic kidney disease. Subsequently, we investigated genetic overlap with eGFR and urinary albumin-creatinine ratio (UACR) variability, based on publicly available CKDgen consortium meta-analysis data. RESULTS In the primary analysis, we found two suggestive hits for kidney failure: rs17046239 in GRM7 (P = 8.9 × 10−8), and rs9273431 in HLA-DQB1 (P = 5.3 × 10−8). In disease-specific analyses, we found three genome-wide (P CONCLUSION We identified three genome-wide significant variants associated with kidney failure due to diabetes and four additional suggestive hits associated with cause-specific or overall kidney failure. The lack of strong genetic overlap with eGFR and UACR suggests that there is a separate genetic component that drives the risk of progression to kidney failure, independent of normal kidney function.

IntroductionKidney transplant recipients (KTR) are at high risk of developing severe COVID-19. However, vaccine response in this population is severely impaired with humoral response rates of 36–54 and 55–69% after two or three doses of SARS-COV-2 vaccines, respectively. Triple immunosuppression and specifically the use of anti-proliferative agents such as mycophenolic acid (MPA) or azathioprine (AZA) have been identified as risk factors for vaccine hypo-responsiveness.MethodsWe hypothesized that in vaccine non-responders to at least three previous vaccine doses, pausing of MPA or AZA for 1 week before and 1 week after an additional vaccination would improve humoral response rates. We conducted an open-label, non-randomized controlled pilot study including 40 KTR with no detectable humoral response after three or four previous vaccine doses. Primary endpoint was seroconversion following SARS-CoV-2 vaccination. MPA and AZA was paused in 18 patients 1 week before until 1 week after an additional vaccine dose while immunosuppression was continued in 22 patients.ResultsThere was no difference in the humoral response rate between the MPA/AZA pause group and the control group (29 vs. 32%, p > 0.99). Absolute antibody levels were also not statistically significantly different between the two groups (p = 0.716).Renal function in the MPA/AZA pause group remained stable and there was no detection of new onset donor-specific antibodies or an increase of donor-derived cell-free DNA serving as a marker of allograft damage throughout the study period.ConclusionPausing of MPA/AZA for 2 weeks peri-vaccination did not increase the rate of seroconversion in kidney transplant. However, one in three KTR without humoral immune response to at least three previous vaccinations developed antibodies after an additional vaccine dose supporting continued vaccination in non-responders.

Aims Myocardial fibrosis is a relevant component of hypertensive heart disease (HHD). Novel cardiovascular magnetic resonance (CMR) imaging techniques have shown potential in quantification of diffuse cardiac fibrosis, with T1 mapping, and estimating preclinical cardiac dysfunction, with strain analysis. Molecular biomarkers of fibrosis have been related with clinical outcomes and histologically proven myocardial fibrosis. The relationship between these CMR-imaging techniques and circulating biomarkers is not fully understood. Methods and results CMR was performed on a 3T scanner in 36 individuals with HHD. Extracellular volume fraction (ECV) and the partition coefficient were assessed using the T1 mapping technique shMOLLI. Longitudinal, circumferential and radial strain was assessed using CMR-Feature Tracking. Molecular biomarkers of collagen synthesis (PICP and PIIINP) and collagen degradation (CITP and MMP-1) were measured in blood using commercial kits. Correlation models showed a significant relationship of T1 mapping measures with left atrial diameter, LV mass, LV posterior wall thickness, LV end-diastolic volume and longitudinal strain. In fully adjusted regression models, ECV was associated with left atrial diameter (β=0.75, P = 0.005) and longitudinal strain (β = 0.43, P = 0.030); the partition coefficient was associated with LV posterior wall thickness (β = 0.53, P = 0.046). Strain measures were associated with cardiac geometry, and longitudinal strain was marginally associated with CITP. Conclusion In individuals with HHD, CMR-derived measures of myocardial fibrosis and function are related and might be useful tools for the identification and characterization of preclinical cardiac dysfunction and diffuse myocardial fibrosis. Molecular biomarkers of fibrosis were marginally associated with myocardial strain, but not with the extension of CMR-measured cardiac fibrosis.

Kidney paired donation (KPD) is a valuable tool to overcome immunological barriers in living donor transplantation. While small national registries encounter difficulties in finding compatible matches, multi-national KPD may be a useful strategy to facilitate transplantation. The Czech (Prague) and Austrian (Vienna) KPD programs, both initiated in 2011, were merged in 2015. A bi-national algorithm allowed for ABO- and low-level HLA antibody-incompatible exchanges, including the option of altruistic donor-initiated domino chains. Between 2011 and 2019, 222 recipients and their incompatible donors were registered. Of those, 95.7% (Prague) and 67.9% (Vienna) entered into KPD registries, and 81 patients received a transplant (95% 3-year graft survival). Inclusion of ABO-incompatible pairs in the Czech program contributed to higher KPD transplant rates (42.6% vs. 23.6% in Austria). After 2015 (11 bi-national match runs), the median pool size increased to 18 pairs, yielding 33 transplants (8 via cross-border exchanges). While matching rates doubled in Austria (from 9.1% to 18.8%), rates decreased in the Czech program, partly due to implementation of more stringent HLA antibody thresholds. Our results demonstrate the feasibility of merging small national KPD programs to increase pool sizes and may encourage the implementation of multi-national registries to expand the full potential of KPD.

ZusammenfassungEs ist bis heute unklar, welche kardialen Untersuchungen bei Patienten mit Niereninsuffizienz in Vorbereitung auf eine Nierentransplantation durchgeführt werden sollen. Das hohe kardiovaskuläre Risiko von Nierenpatienten bedingt allerdings eine Abklärung vor dem geplanten Eingriff. Während manche Zentren bei den vorgesehenen Untersuchungen sehr zurückhaltend sind, schlagen andere eine invasive Untersuchung mittels Koronarangiographie vor. Eine konsequente Einschätzung der Vortestwahrscheinlichkeit einer kardialen Pathologie sollte vor der Testauswahl erfolgen, um unnötige nichtinvasive Test bei Hochrisikopatienten zu vermeiden. Wird schließlich eine koronare Herzerkrankung nachgewiesen, sind weitere Frage nach der adäquaten Versorgung der kritischen Koronarläsionen zu klären, obwohl eine breite evidenzbasierte Datenlage dazu noch nicht existiert. Ob einer konservativen Behandlung oder einer Sanierung mittels Angioplastie/Stenting bzw. einer Bypassoperation der Vorzug gegeben wird, hängt von der Ausprägung der Koronarerkrankung ab und muss in Absprache mit Kardiologen und Herzchirurgen festgelegt werden.

The 2020 Kidney Disease: Improving Global Outcomes (KDIGO) Clinical Practice Guideline on the Evaluation and Management of Candidates for Kidney Transplantation is intended to assist health care professionals worldwide who evaluate and manage potential candidates for deceased or living donor kidney transplantation. This guideline addresses general candidacy issues such as access to transplantation, patient demographic and health status factors, immunological and psychosocial assessment. The roles of various risk factors and comorbid conditions governing an individual's suitability for transplantation such as adherence, tobacco use, diabetes, obesity, perioperative issues, causes of kidney failure, infections, malignancy, pulmonary disease, cardiac and peripheral arterial disease, neurologic disease, gastrointestinal and liver disease, hematologic disease, and bone and mineral disorder are also addressed. This guideline provides recommendations for evaluation of individual aspects of a candidate's profile such that each risk factor and comorbidity are considered separately. The goal is to assist the clinical team to assimilate all data relevant to an individual, consider this within their local health context, and make an overall judgment on candidacy for transplantation. The guideline development process followed the Grades of Recommendation Assessment, Development, and Evaluation (GRADE) approach. Guideline recommendations are primarily based on systematic reviews of relevant studies and our assessment of the quality of that evidence. The strengths of recommendations are provided in the full report. Limitations of the evidence are discussed with differences from previous guidelines noted and suggestions for future research are also provided.

ImportanceResponse to SARS-CoV-2 vaccines in kidney transplant recipients (KTR) is severely reduced. Heterologous 3rd vaccination combining mRNA and vector vaccines did not increase seroconversion at four weeks after vaccination but evolution of antibody levels beyond the first month remain unknown.ObjectiveTo assess changes in antibody response following a 3rd vaccination with mRNA or vector vaccine in KTR from month one to month three after vaccination.Design, Setting and ParticipantsThree-month follow-up (pre-specified secondary endpoint) of a single-center, single-blinded, 1:1 randomized, controlled trial on 3rd vaccination against SARS-CoV-2 in 201 KTR who did not develop SARS-CoV-2 spike protein antibodies following two doses of an mRNA vaccine.Intervention(s)mRNA (BNT162b2 or mRNA-1273) or vector (Ad26COVS1) as 3rd SARS-CoV-2 vaccineMain Outcomes and MeasuresMain outcome was seroconversion at the second follow-up between 60-120 days after the 3rd vaccination. Subsequently, higher cut-off levels associated with neutralizing capacity and protective immunity were applied (i.e. >15, >100, >141 and >264 BAU/mL). In addition, trajectories of antibody levels from month one to month three were analyzed. Finally, SARS-CoV-2 specific CD4 and CD8 T-cells at four weeks were compared among the 18 top responders in both groups.ResultsA total of 169 patients were available for the three-month follow-up. Overall, seroconversion at three months was similar between both groups (45% versus 50% for mRNA and vector group, respectively; OR=1.24, 95%CI=[0.65, 2.37], p=0.539). However, when applying higher cut-off levels, a significantly larger number of individual in the vector group reached antibody levels > 141 and > 264 BAU/mL at the three-month follow-up (141 BAU/mL: 4% vs. 15% OR=4.96, 95%CI=[1.29, 28.21], p=0.009 and 264 BAU/mL: 1% vs. 10% OR=8.75, 95%CI=[1.13, 396.17], p=0.018 for mRNA vs. vector vaccine group, respectively). In line, antibody levels in seroconverted patients further increased from month one to month three in the vector group while remaining unchanged in the mRNA group (median increase: mRNA= 1.35 U/mL and vector = 27.6 U/mL, p = 0.004). Of particular note, there was no difference in the CD4 and CD8 T-cell response between the mRNA and vector vaccine group at month one.Conclusions and RelevanceDespite a similar overall seroconversion rate at three months following 3rd vaccination in KTR, a heterologous 3rd booster vaccination with Ad26COVS1 resulted in significantly higher antibody levels in responders.Trial RegistrationEurdraCT: 2021-002927-39

Fibroblast growth factor 23 (FGF23) is elevated in patients with chronic kidney disease and contributes to left ventricular hypertrophy (LVH). The aim of the analysis was to determine whether this effect is mediated by the renin-angiotensin-aldosterone system (RAAS) in hemodialysis. Serum samples from 62 randomized hemodialysis patients with LVH were analyzed for plasma renin activity (PRA-S), angiotensin II (AngII), and metabolites, angiotensin-converting enzyme-2 (ACE2) and aldosterone using a high throughput mass spectrometry assay. Compared to healthy individuals, levels of the RAAS parameters PRA-S, AngII and aldosterone were generally lower [median (IQR) PRA-S 130 (46–269) vs. 196 (98, 238) pmol/L; AngII 70 (28–157) vs. 137 (76, 201) pmol/L; Aldosterone 130 (54, 278) vs. 196 (98, 238) pmol/L]. We did not find an indication that the effect of FGF23 on LVH was mediated by RAAS parameters, with all estimated indirect effects virtually zero. Furthermore, FGF23 was not associated with RAAS parameter levels throughout the study. While there was a clear association between FGF23 levels and left ventricular mass index (LVMI) at the end of the study and in the FGF23 fold change and LVMI change analysis, no association between RAAS and LVMI was observed. Serum concentrations of PRA-S, AngII, and aldosterone were below the ranges measured in healthy controls suggesting that RAAS is not systemically activated in hemodialysis patients. The effect of FGF23 on LVMI was not mediated by systemic RAAS activity. These findings challenge the current paradigm of LVH progression and treatment with RAAS blockers in dialysis.Clinical Trial Registration[https://clinicaltrials.gov/ct2/show/NCT03182699], identifier [NCT03182699].

Antibody-mediated rejection; Biopsy; Kidney transplantation Rechazo mediado por anticuerpos; Biopsia; Trasplante renal Rebuig mediat per anticossos; Biòpsia; Trasplantament renal Antibody-mediated rejection (AMR) is caused by antibodies that recognize donor human leukocyte antigen (HLA) or other targets. As knowledge of AMR pathophysiology has increased, a combination of factors is necessary to confirm the diagnosis and phenotype. However, frequent modifications to the AMR definition have made it difficult to compare data and evaluate associations between AMR and graft outcome. The present paper was developed following a Broad Scientific Advice request from the European Society for Organ Transplantation (ESOT) to the European Medicines Agency (EMA), which explored whether updating guidelines on clinical trial endpoints would encourage innovations in kidney transplantation research. ESOT considers that an AMR diagnosis must be based on a combination of histopathological factors and presence of donor-specific HLA antibodies in the recipient. Evidence for associations between individual features of AMR and impaired graft outcome is noted for microvascular inflammation scores ≥2 and glomerular basement membrane splitting of >10% of the entire tuft in the most severely affected glomerulus. Together, these should form the basis for AMR-related endpoints in clinical trials of kidney transplantation, although modifications and restrictions to the Banff diagnostic definition of AMR are proposed for this purpose. The EMA provided recommendations based on this Broad Scientific Advice request in December 2020; further discussion, and consensus on the restricted definition of the AMR endpoint, is required. This initiative was supported by the European Society for Organ Transplantation.

Clinical risk factors explain only a fraction of the variability of estimated glomerular filtration rate (eGFR) decline in people with type 2 diabetes. Cross-omics technologies by virtue of a wide spectrum screening of plasma samples have the potential to identify biomarkers for the refinement of prognosis in addition to clinical variables. Here we utilized proteomics, metabolomics and lipidomics panel assay measurements in baseline plasma samples from the multinational PROVALID study (PROspective cohort study in patients with type 2 diabetes mellitus for VALIDation of biomarkers) of patients with incident or early chronic kidney disease (median follow-up 35 months, median baseline eGFR 84 mL/min/1.73 m(2), urine albumin-to-creatinine ratio 8.1 mg/g). In an accelerated case-control study, 258 individuals with a stable eGFR course (median eGFR change 0.1 mL/min/year) were compared to 223 individuals with a rapid eGFR decline (median eGFR decline -6.75 mL/min/year) using Bayesian multivariable logistic regression models to assess the discrimination of eGFR trajectories. The analysis included 402 candidate predictors and showed two protein markers (KIM-1, NTproBNP) to be relevant predictors of the eGFR trajectory with baseline eGFR being an important clinical covariate. The inclusion of metabolomic and lipidomic platforms did not improve discrimination substantially. Predictions using all available variables were statistically indistinguishable from predictions using only KIM-1 and baseline eGFR (area under the receiver operating characteristic curve 0.63). Thus, the discrimination of eGFR trajectories in patients with incident or early diabetic kidney disease and maintained baseline eGFR was modest and the protein marker KIM-1 was the most important predictor.

BackgroundPre-sensitized kidney transplant recipients have a higher risk for rejection following kidney transplantation and therefore receive lymphodepletional induction therapy with anti-human T-lymphocyte globulin (ATLG) whereas non-sensitized patients are induced in many centers with basiliximab. The time course of lymphocyte reconstitution with regard to the overall and donor-reactive T-cell receptor (TCR) specificity remains elusive.Methods/DesignFive kidney transplant recipients receiving a 1.5-mg/kg ATLG induction therapy over 7 days and five patients with 2 × 20 mg basiliximab induction therapy were longitudinally monitored. Peripheral mononuclear cells were sampled pre-transplant and within 1, 3, and 12 months after transplantation, and their overall and donor-reactive TCRs were determined by next-generation sequencing of the TCR beta CDR3 region. Overall TCR repertoire diversity, turnover, and donor specificity were assessed at all timepoints.ResultsWe observed an increase in the donor-reactive TCR repertoire after transplantation in patients, independent of lymphocyte counts or induction therapy. Donor-reactive CD4 T-cell frequency in the ATLG group increased from 1.14% + -0.63 to 2.03% + -1.09 and from 0.93% + -0.63 to 1.82% + -1.17 in the basiliximab group in the first month. Diversity measurements of the entire T-cell repertoire and repertoire turnover showed no statistical difference between the two induction therapies. The difference in mean clonality between groups was 0.03 and 0.07 pre-transplant in the CD4 and CD8 fractions, respectively, and was not different over time (CD4: F(1.45, 11.6) = 0.64 p = 0.496; CD8: F(3, 24) = 0.60 p = 0.620). The mean difference in R20, a metric for immune dominance, between groups was -0.006 in CD4 and 0.001 in CD8 T-cells and not statistically different between the groups and subsequent timepoints (CD4: F(3, 24) = 0.85 p = 0.479; CD8: F(1.19, 9.52) = 0.79 p = 0.418).ConclusionReduced-dose ATLG induction therapy led to an initial lymphodepletion followed by an increase in the percentage of donor-reactive T-cells after transplantation similar to basiliximab induction therapy. Furthermore, reduced-dose ATLG did not change the overall TCR repertoire in terms of a narrowed or skewed TCR repertoire after immune reconstitution, comparable to non-depletional induction therapy.

Skeletal muscle area (SMA) in the computed tomography (CT) at the third lumbar vertebra (L3) level is a proxy for whole-body muscle mass but is only performed for clinical reasons. Ultrasound is a promising tool to determine muscle mass at the bedside. It is still unclear how well ultrasound and which ultrasound measuring points can predict CT L3 SMA.This prospective observational trial included 200 non-critically ill patients, who underwent an abdominal CT scan for any clinical reason within 48 h before the ultrasound examination. Ultrasound muscle thickness was evaluated at 3 measuring points on the thigh and 2 measuring points on the upper arm with minimal compression. On the CT scan, the entire L3 SMA was measured based on Hounsfield units. Using a model selection algorithm based on the Bayesian information criterion (BIC) and clinical considerations, a linear prediction model for CT L3 SMA based on the ultrasound muscle thickness and other independent variables was fitted and assessed with cross-validation.67,5% and 32,5% of the patients were from surgical and medical wards, respectively. Mean ultrasound muscle thickness values were between 2,2 and 3,6 cm on the thigh and between 1,4 and 2,8 cm on the upper arm. All ultrasound muscle thickness values were higher in men than in women (P 0,05). CT L3 SMA was 40 cmOne single ultrasound measuring point at the thigh together with sex, height and weight very well predicts CT L3 SMA across different clinical populations. Ultrasound is a safe and bedside method to measure muscle thickness longitudinally to monitor the effects of nutrition and physical therapy.

Alloimmune risk; High-risk transplantation; Individualized immunosuppression Riesgo aloinmune; Trasplante de alto riesgo; Inmunosupresión individualizada Risc aloimmune; Trasplantament d'alt risc; Immunosupressió individualitzada Different types of kidney transplantations are performed worldwide, including biologically diverse donor/recipient combinations, which entail distinct patient/graft outcomes. Thus, proper immunological and non-immunological risk stratification should be considered, especially for patients included in interventional randomized clinical trials. This paper was prepared by a working group within the European Society for Organ Transplantation, which submitted a Broad Scientific Advice request to the European Medicines Agency (EMA) relating to clinical trial endpoints in kidney transplantation. After collaborative interactions, the EMA sent its final response in December 2020, highlighting the following: 1) transplantations performed between human leukocyte antigen (HLA)-identical donors and recipients carry significantly lower immunological risk than those from HLA-mismatched donors; 2) for the same allogeneic molecular HLA mismatch load, kidney grafts from living donors carry significantly lower immunological risk because they are better preserved and therefore less immunogenic than grafts from deceased donors; 3) single-antigen bead testing is the gold standard to establish the repertoire of serological sensitization and is used to define the presence of a recipient’s circulating donor-specific antibodies (HLA-DSA); 4) molecular HLA mismatch analysis should help to further improve organ allocation compatibility and stratify immunological risk for primary alloimmune activation, but without consensus regarding which algorithm and cut-off to use it is difficult to integrate information into clinical practice/study design; 5) further clinical validation of other immune assays, such as those measuring anti-donor cellular memory (T/B cell ELISpot assays) and non–HLA-DSA, is needed; 6) routine clinical tests that reliably measure innate immune alloreactivity are lacking. This initiative was supported by the European Society for Organ Transplantation.

Background Chronic kidney disease (CKD) is a well-established complication in people with diabetes mellitus. Roughly one quarter of prevalent patients with diabetes exhibit a CKD stage of 3 or higher and the individual course of progression is highly variable. Therefore, there is a clear need to identify patients at high risk for fast progression and the implementation of preventative strategies. Existing prediction models of renal function decline, however, aim to assess the risk by artificially grouped patients prior to model building into risk strata defined by the categorization of the least-squares slope through the longitudinally fluctuating eGFR values, resulting in a loss of predictive precision and accuracy. Methods This study protocol describes the development and validation of a prediction model for the longitudinal progression of renal function decline in Caucasian patients with type 2 diabetes mellitus (DM2). For development and internal-external validation, two prospective multicenter observational studies will be used (PROVALID and GCKD). The estimated glomerular filtration rate (eGFR) obtained at baseline and at all planned follow-up visits will be the longitudinal outcome. Demographics, clinical information and laboratory measurements available at a baseline visit will be used as predictors in addition to random country-specific intercepts to account for the clustered data. A multivariable mixed-effects model including the main effects of the clinical variables and their interactions with time will be fitted. In application, this model can be used to obtain personalized predictions of an eGFR trajectory conditional on baseline eGFR values. The final model will then undergo external validation using a third prospective cohort (DIACORE). The final prediction model will be made publicly available through the implementation of an R shiny web application. Discussion Our proposed state-of-the-art methodology will be developed using multiple multicentre study cohorts of people with DM2 in various CKD stages at baseline, who have received modern therapeutic treatment strategies of diabetic kidney disease in contrast to previous models. Hence, we anticipate that the multivariable prediction model will aid as an additional informative tool to determine the patient-specific progression of renal function and provide a useful guide to early on identify individuals with DM2 at high risk for rapid progression.

The coronavirus disease 2019 (COVID-19) pandemic poses important challenges to the care of patients with immune-mediated kidney diseases and to kidney transplant recipients. Here, we discuss the management of immunosuppression for these patients during the pandemic and suggest potential approaches that could be considered in the absence of validated strategies.

Steroid pretreatment of deceased donors reduces inflammation in allografts and is recommended by organ procurement guidelines. The impact on long‐term graft outcome, however, remains elusive. In this multicenter randomized controlled trial, 306 deceased donors providing organs for 455 renal transplant recipients were randomized to 1000 mg of methylprednisolone or placebo prior to organ procurement (ISRCTN78828338). The incidence of biopsy‐confirmed rejection (Banff>1) at 3 months was 23 (10%) in the steroid group and 26 (12%) in the placebo group (P = .468). Five‐year functional graft survival was 84% and 82% for the steroid group and placebo group, respectively (P‐value = .941). The hazard ratio of functional graft loss was 0.90 (95% confidence interval 0.57‐1.42, P = .638) for steroid vs placebo in a multivariate Cox model. We did not observe effect modification by any of the predictors of graft survival and treatment modality. A robust sandwich estimate was used to account for paired grafts of some donors. The mean estimated GFR at 5 years was 47 mL/min per 1.73 m2 in the steroid group and 48 mL/min per 1.73 m2 in the placebo group (P = .756). We conclude that steroid pretreatment does not impact on long‐term graft survival. In a donor population with higher risk of delayed graft function, however, repetitive and higher doses of steroid treatment may result in different findings., Steroid pretreatment of deceased organ donors using a single 1000 mg dose of methylprednisolone does not reduce the incidence of biopsy‐confirmed acute rejection episodes within the first 3 months posttransplantation and does not improve 5‐year functional graft survival compared to placebo, despite reduction of inflammation signatures in preimplantation biopsies.

Recent epidemiological investigations have shown that approximately 2-3% of all Austrians suffer from diabetes with renal involvement, i. e. 250,000 people in Austria are affected. The risk of occurrence and progression of this disease can be ameliorated by life style interventions as well as optimization of blood pressure, blood glucose levels and special drug classes. The present article represents the joint recommendations of the Austrian Diabetes Association and the Austrian Society for Nephrology for the diagnostics and treatment strategies of diabetic kidney disease.

Current proposals for waiting times for a renal transplant after malignant disease may not be appropriate. New data on malignancies in end-stage renal disease and recent diagnostic and therapeutic options should lead us to reconsider our current practice.

Background and Aims Kidney transplantation is considered to be the optimal treatment strategy for eligible end stage renal disease patients. However, the body of evidence to underpin the anticipated survival advantage for kidney transplant recipients is weak, as random treatment allocation to either kidney transplantation or remaining on dialysis is not feasible and previously reported results obtained from observational studies did not allow for causal interpretation. The aim of this study is to investigate survival differences of kidney transplantation compared to remaining waitlisted on dialysis across different transplant candidate ages applying causal inference methodology. Method We conducted a retrospective cohort study using the Austrian Dialysis and Transplant Registry. We included all maintenance dialysis patients who were waitlisted for their first kidney transplant between January 2000 and December 2018 and utilized repeated updates on waitlisting status and relevant covariates. To estimate the causal effect of kidney transplantation compared to remaining waitlisted on all-cause survival we applied a sequential Cox approach mimicking a series of target trials, where each trial started at the time of a transplantation. In each of these emulated trials transplanted patients were classified as treated and patients with current active waitlisting status as controls, and the groups were balanced for covariates by inverse probability weighting. Controls who were transplanted at later times were censored but assigned to the treated group in a later target trial of the series. All trials were combined into a single data set and analyzed by a Cox proportional hazards model using inverse probability weighting also to adjust for artificial censoring. Additionally, we evaluated potential effect modifications by age at trial initiation (continuous) and stratified our analyses by time on waitlist before trial initiation (up to 1 year, between 1 and 2 years, and more than 2 years). Results are reported as hazard ratios (HRs), 5-year survival probabilities and restricted mean survival time together with respective bootstrap confidence intervals (CIs). Results The study cohort consisted of 4206 patients, of whom one third were women and the mean age was 52 years. In total, 3399 patients (81%) received a transplant and 1256 patients died. The median time from waitlisting to transplantation was 1.8 years. Overall, patients who received a kidney transplant had a significant survival benefit compared to patients who remained waitlisted (HR 0.36, 95% CI 0.29 to 0.43). Assessing survival across different ages showed a significant benefit for kidney transplantation for patients between 32 and 77 years of age at time of transplantation (e.g. HR at age of 70: 0.43, 95% CI 0.33 to 0.54). For older and younger patients our analysis did not provide definitive conclusions due to limited sample sizes. Transplanted patients had higher predicted survival and longer restricted mean survival time compared to patients remaining waitlisted. For example, within 5 years after engraftment, a transplanted patient 70 years of age at trial initiation had a 0.28 higher survival probability (95% CI 0.20-0.37) and was expected to gain 0.75 years of survival time. Our stratified analyses showed a survival benefit for kidney transplantation regardless of time on waitlist before trial initiation across all ages. Conclusion Our study provides robust evidence based on state-of-the-art causal inference methodology for increased survival after kidney transplantation across different transplant candidate ages and irrespective of time on waiting list.

Rationale: Left ventricular hypertrophy (LVH) is highly prevalent in patients with chronic kidney disease and increases their risk of cardiac events and mortality. FGF23 (fibroblast growth factor 23) and parathyroid hormone levels, which are associated with the development of LVH, rise progressively with declining renal function. Objectives: To determine whether FGF23 suppression by calcimimetic therapy may reduce LVH progression in comparison to FGF23 elevation under vitamin D analogs at equal parathyroid hormone suppression under either therapy as well as tight volume control. Methods and Results: We conducted a single-blinded trial with 1:1 block randomization to investigate the effect of the intravenous treatment with etelcalcetide versus alfacalcidol on LVH progression in 62 maintenance hemodialysis patients with secondary hyperparathyroidism and LVH. In the intention-to-treat analysis of 59 patients, the mean difference in the change of left ventricular mass index determined by cardiac magnetic resonance imaging from baseline to 12 months of treatment was −6.9 g/m 2 (95% CI, −12.6 to −1.2, P =0.022) in the etelcalcetide compared with the alfacalcidol group. The effect estimate was −8.2 g/m 2 (95% CI, −14 to −2.4) in the per-protocol analysis on 52 patients. The trajectories of parathyroid hormone, phosphate, and αKlotho were similar in both groups throughout follow-up. FGF23 levels, which showed a strong positive association with left ventricular mass index, were decreasing under etelcalcetide and increasing under alfacalcidol at similar parathyroid hormone suppression. Mild hypocalcemia was the most common adverse event under etelcalcetide. Blood pressure and the distribution of antihypertensive medications were similar between groups. Conclusions: In this trial, we were able to show that FGF23 suppression by etelcalcetide inhibited the progression of LVH compared with alfacalcidol in hemodialysis patients. A successful prevention of increasing hypertrophy may reduce the risk of sudden cardiac death in this population. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03182699.

The premises of kidney transplantation treatment have not changed much in the last decades. Short-term results are excellent, but long-term graft outcome is limited. While transplantation is regarded as the best treatment for end stage renal disease, it is potentially accompanied by significant co-morbidities the management of which is complicated by fundamentally unresolved issues, which pose challenges to clinicians and scientists alike.

The authors have requested that this preprint be removed from Research Square.

Pathological erythropoiesis with consequent anemia is a leading cause of symptomatic morbidity in internal medicine. The etiologies of anemia are complex and include reactive as well as neoplastic conditions. Clonal expansion of erythroid cells in the bone marrow may result in peripheral erythrocytosis and polycythemia but can also result in anemia when clonal cells are dysplastic and have a maturation arrest that leads to apoptosis and hinders migration, a constellation typically seen in the myelodysplastic syndromes. Rarely, clonal expansion of immature erythroid blasts results in a clinical picture resembling erythroid leukemia. Although several mechanisms underlying normal and abnormal erythropoiesis and the pathogenesis of related disorders have been deciphered in recent years, little is known about specific markers and targets through which prognosis and therapy could be improved in anemic or polycythemic patients. In order to discuss new markers, targets and novel therapeutic approaches in erythroid disorders and the related pathologies, a workshop was organized in Vienna in April 2017. The outcomes of this workshop are summarized in this review, which includes a discussion of new diagnostic and prognostic markers, the updated WHO classification, and an overview of new drugs used to stimulate or to interfere with erythropoiesis in various neoplastic and reactive conditions. The use and usefulness of established and novel erythropoiesis-stimulating agents for various indications, including myelodysplastic syndromes and other neoplasms, are also discussed.

Pre-emptive kidney transplantation is the recommended strategy for patients with end-stage renal failure in all guidelines [Kidney Disease: Improving Global Outcomes (KDIGO), The Australian and New Zealand Dialysis and Transplantation Registry (ANZDATA), European Renal Best Practice Guideline (ERBP), British Transplant Society (BTS)]. This recommendation is intuitive and based on few older studies with considerable limitations. In addition, there is conflicting evidence as to whether the duration of dialysis vintage impacts on graft and patient survival after transplantation. The objective of this structured review was to critically review the published evidence on dialysis vintage and outcomes by including the most recent papers on that topic. We searched Medline using keywords for kidney transplantation, pre-emptive, dialysis vintage and relevant outcomes, and found 14 eligible cohort studies. The best evidence was found for pre-emptive transplantation, which was found to be associated with a lower risk of actual graft loss (including death as event) compared with non-pre-emptive transplantation. When only patients were considered that have been registered pre-emptively but then received or did not receive a pre-emptive transplant, the association with functional graft survival (excluding death as event) was only marginal. Dialysis vintage had a graded association with patient survival in most of the studies, but an unclear estimate with functional graft survival. Older studies also found an association of dialysis vintage with death-censored graft survival, but this association is likely confounded by selection and the competing risk of death and was no longer observed in recent eras, i.e. in transplants performed in the last decade. In summary, the recommendation for pre-emptive kidney transplantation for optimal patient and graft survival remains valid even in recent periods but the association of dialysis vintage after dialysis initiation with death-censored graft survival is less clear. The association of dialysis vintage with mortality after transplantation depends on the median duration of dialysis of the wait-listed population as well as acceptance rates for transplantation, and may thus be country specific. Nevertheless, it is reasonable to advocate pre-emptive kidney transplantation in all age groups. What remains unsolved is the selection issues since the reasons for longer waiting time on dialysis are difficult to capture in retrospective observational studies, and lead time as well as immortal time bias may have confounded the mortality data.

Background Nephronophthisis (NPH) is the most prevalent genetic cause for ESRD in children. However, little is known about the prevalence of NPH in adult-onset ESRD. Homozygous full gene deletions of the NPHP1 gene encoding nephrocystin-1 are a prominent cause of NPH. We determined the prevalence of NPH in adults by assessing homozygous NPHP1 full gene deletions in adult-onset ESRD.Methods Adult renal transplant recipients from five cohorts of the International Genetics and Translational Research in Transplantation Network (iGeneTRAiN) underwent single-nucleotide polymorphism genotyping. After quality control, we determined autosomal copy number variants (such as deletions) on the basis of median log2 ratios and B-allele frequency patterns. The findings were independently validated in one cohort. Patients were included in the analysis if they had adult-onset ESRD, defined as start of RRT at >= 18 years old.Results We included 5606 patients with adult-onset ESRD; 26 (0.5%) showed homozygous NPHP1 deletions. No donor controls showed homozygosity for this deletion. Median age at ESRD onset was 30 (range, 18-61) years old for patients with NPH, with 54% of patients age >= 30 years old. Notably, only three (12%) patients were phenotypically classified as having NPH, whereas most patients were defined as having CKD with unknown etiology (n=11; 42%).Conclusions Considering that other mutation types in NPHP1 or mutations in other NPH-causing genes were not analyzed, NPH is a relatively frequent monogenic cause of adult-onset ESRD. Because 88% of patients had not been clinically diagnosed with NPH, wider application of genetic testing in adult-onset ESRD may be warranted.

Late antibody-mediated rejection (ABMR) is a leading cause of kidney allograft failure. Uncontrolled studies have suggested efficacy of the proteasome inhibitor bortezomib, but no systematic trial has been undertaken to support its use in ABMR. In this randomized, placebo-controlled trial (the Bortezomib in Late Antibody-Mediated Kidney Transplant Rejection [BORTEJECT] Trial), we investigated whether two cycles of bortezomib (each cycle: 1.3 mg/m2 intravenously on days 1, 4, 8, and 11) prevent GFR decline by halting the progression of late donor-specific antibody (DSA)–positive ABMR. Forty-four DSA-positive kidney transplant recipients with characteristic ABMR morphology (median time after transplant, 5.0 years; pretransplant DSA documented in 19 recipients), who were identified on cross-sectional screening of 741 patients, were randomly assigned to receive bortezomib (n=21) or placebo (n=23). The 0.5-ml/min per 1.73 m2 per year (95% confidence interval, −4.8 to 5.8) difference detected between bortezomib and placebo in eGFR slope (primary end point) was not significant (P=0.86). We detected no significant differences between bortezomib- and placebo-treated groups in median measured GFR at 24 months (33 versus 42 ml/min per 1.73 m2; P=0.31), 2-year graft survival (81% versus 96%; P=0.12), urinary protein concentration, DSA levels, or morphologic or molecular rejection phenotypes in 24-month follow-up biopsy specimens. Bortezomib, however, associated with gastrointestinal and hematologic toxicity. In conclusion, our trial failed to show that bortezomib prevents GFR loss, improves histologic or molecular disease features, or reduces DSA, despite significant toxicity. Our results reinforce the need for systematic trials to dissect the efficiency and safety of new treatments for late ABMR.

Immortal time bias is a problem arising from methodologically wrong analyses of time-dependent events in survival analyses. We illustrate the problem by analysis of a kidney transplantation study. Following patients from transplantation to death, groups defined by the occurrence or nonoccurrence of graft failure during follow-up seemingly had equal overall mortality. Such naive analysis assumes that patients were assigned to the two groups at time of transplantation, which actually are a consequence of occurrence of a time-dependent event later during follow-up. We introduce landmark analysis as the method of choice to avoid immortal time bias. Landmark analysis splits the follow-up time at a common, prespecified time point, the so-called landmark. Groups are then defined by time-dependent events having occurred before the landmark, and outcome events are only considered if occurring after the landmark. Landmark analysis can be easily implemented with common statistical software. In our kidney transplantation example, landmark analyses with landmarks set at 30 and 60 months clearly identified graft failure as a risk factor for overall mortality. We give further typical examples from transplantation research and discuss strengths and limitations of landmark analysis and other methods to address immortal time bias such as Cox regression with time-dependent covariables.

Background: Inconsistencies in outcome reporting and frequent omission of patient-centered outcomes can diminish the value of trials in treatment decision-making. We identified critically important outcome domains in kidney transplantation based on the shared priorities of patients/caregivers and health professionals. Methods: In a 3-round Delphi survey, patients/caregivers and health professionals rated the importance of outcome domains for trials in kidney transplantation on a 9-point Likert scale and provided comments. During Round 2 and 3, participants re-rated the outcomes after reviewing their own score, the distribution of the respondents’ scores, and comments. We calculated the median, mean, and proportion rating 7-9 (critically important), and analyzed comments thematically. Results: 1018 participants (461 [45%] patients/caregivers and 557 [55%] health professionals) from 79 countries completed Round 1, and 779 (77%) completed Round 3. The top eight outcomes that met the consensus criteria in Round 3 (mean ≥7.5, median ≥8 and proportion >85%) in both groups were graft loss, graft function, chronic rejection, acute rejection, mortality, infection, cancer (excluding skin) and cardiovascular disease. Compared with health professionals, patients/caregivers gave higher priority to six outcomes (mean difference of 0.5 or more): skin cancer, surgical complications, cognition, blood pressure, depression, and ability to work. We identified five themes: capacity to control and inevitability, personal relevance, debilitating repercussions, gaining awareness of risks, and addressing knowledge gaps. Conclusions: Graft complications and severe comorbidities were critically important for both stakeholder groups. These stakeholder-prioritized outcomes will inform the core outcome set to improve the consistency and relevance of trials in kidney transplantation.

Background Recently, diffuse peritubular capillaritis (ptc) has been suggested to independently predict chronic transplant injury and loss, and although the ptc score is a diagnostic criterion for antibody-mediated rejection, the utility of diffuse ptc is under debate. Methods We evaluated the diagnostic value of ptc characteristics in this cross-sectional study including 85 biopsies of patients with donor-specific antibodies (DSA). Biopsies were reevaluated for the extent (diffuse vs focal), score and leukocytic composition in relation to DSA binding strength (mean fluorescence intensity [MFI]_max). Chronic allograft injury (transplant chronic glomerulopathy [cg] or chronic lesion score CLS]) were associated with ptc features. Results Peritubular capillaritis was detected in 50% (76% mononuclear ptc). Peritubular capillaritis scores 1, 2, and 3 were present in 36%, 55%, and 9%, and focal or diffuse ptc in 36% or 64%. Diffuse ptc was associated with DSA MFI_max (median: 4407 vs 2419 [focal ptc; P = 0.04] or 1946 [no ptc; P = 0.004]), cg (58% vs no ptc 24% [P = 0.02]), and higher CLS (mean: 6.81 vs 4.67 [focal ptc, P = 0.01] or 5.18 [no ptc, P = 0.001]), respectively. The association of ptc score of 2 or greater with cg was slightly better than with diffuse ptc. Diffuse ptc and ptc score of 2 or greater remained independently related to cg after adjusting for DSA_MFI_max, C4d, or previous rejection episodes, however lost their independent relation after adjusting for total microcirculation scores. Diffuse ptc was the only ptc characteristic independently related to CLS. Conclusions Our results emphasize the clinical relevance of reporting diffuse ptc, which may relate to DSA binding strength and potentially to chronic graft injury.

Summary Kidney transplantation has become a routine procedure in the treatment of patients with kidney failure, and requires collaboration of experts from different disciplines, such as nephrology, surgery, immunology, pathology, infectious disease medicine, cardiology, and oncology. Grafts can be obtained from deceased or living donors, with different logistical requirements and implications for long-term graft patency. 1-year graft survival rates are greater than 95% in many centres but improvement of long-term function remains a challenge. New developments in molecular immunology and computational biology have increased precision of donor and recipient matching of HLA and non-HLA compatibility. Individual omics-wide molecular diagnostics, extracorporeal therapies, and drug developments allow for precise individual decision making and treatment. Tolerance induction by mixed chimerism without toxic conditioning and with a low risk of graft versus host disease is a visionary but realistic goal. Some of these innovations are already used in modern transplant centres and will allow advancement in long-term allograft preservation.

Circulating donor-specific antibodies (DSA) detected on bead arrays may not inevitably indicate ongoing antibody-mediated rejection (AMR). Here, we investigated whether detection of complement-fixation, in parallel to IgG mean fluorescence intensity (MFI), allows for improved prediction of AMR.Our study included 86 DSA+ kidney transplant recipients subjected to protocol biopsy, who were identified upon cross-sectional antibody screening of 741 recipients with stable graft function at 6 months or longer after transplantation. IgG MFI was analyzed after elimination of prozone effect, and complement-fixation was determined using C1q, C4d, or C3d assays.Among DSA+ study patients, 44 recipients (51%) had AMR, 24 of them showing C4d-positive rejection. Although DSA number or HLA class specificity were not different, patients with AMR or C4d + AMR showed significantly higher IgG, C1q, and C3d DSA MFI than nonrejecting or C4d-negative patients, respectively. Overall, the predictive value of DSA characteristics was moderate, whereby the highest accuracy was computed for peak IgG MFI (AMR, 0.73; C4d + AMR, 0.71). Combined analysis of antibody characteristics in multivariate models did not improve AMR prediction.We estimate a 50% prevalence of silent AMR in DSA+ long-term recipients and conclude that assessment of IgG MFI may add predictive accuracy, without an independent diagnostic advantage of detecting complement-fixation.

Acute kidney injury (AKI) remains a major clinical event with high mortality rates. We previously identified renal miR-182 as the main driver of post-transplantation AKI. Therefore, we tested the causal inference of miR-182 by inhibiting its renal expression in vivo. In 45 rats AKI was induced by right nephrectomy and contralateral clamping of the renal pedicle for 40 minutes. Systemically administered antisense oligonucleotide (ASO) inhibited miR-182 in the kidneys up to 96 hours. The maximum creatinine elevation was on day 2 after injury (mg/dL; median and interquartile range): ASO 2.5mg/kg: 1.9 (1.3; 3.2), ASO 25mg/kg: 2.8 (0.7; 5.0), mismatch oligonucleotide (MM) 25mg/kg: 5.7 (5,0; 5.8), saline: 4.4 (3.5; 5.8) (P = 0.016, analysis of variance). Blinded semiquantitative histologic evaluation of renal biopsies showed better preserved morphology in both ASO groups than saline- and MM-treated kidneys (median and interquartile range of overall injury scores): ASO both concentrations 1 (1, 1), saline 3 (3, 3) and MM 3 (3, 3) (P0.001, analysis of variance). ASO facilitated cell proliferation, metabolism, and angiogenesis on a genome-wide level. ASO when applied in normothermic kidney machine perfusion reduced renal miR-182 expression by more than two magnitudes. In summary, we showed that in vivo inhibition of miR-182 by ASO improved kidney function and morphology after AKI. This technique may be applicable to reduce the high rate of AKI in the human renal transplantation setting.