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Kidney fibrosis constitutes the shared final pathway of nearly all chronic nephropathies, but biomarkers for the non-invasive assessment of kidney fibrosis are currently not available. To address this, we characterize five candidate biomarkers of kidney fibrosis: Cadherin-11 (CDH11), Sparc-related modular calcium binding protein-2 (SMOC2), Pigment epithelium-derived factor (PEDF), Matrix-Gla protein, and Thrombospondin-2. Gene expression profiles in single-cell and single-nucleus RNA-sequencing (sc/snRNA-seq) datasets from rodent models of fibrosis and human chronic kidney disease (CKD) were explored, and Luminex-based assays for each biomarker were developed. Plasma and urine biomarker levels were measured using independent prospective cohorts of CKD: the Boston Kidney Biopsy Cohort, a cohort of individuals with biopsy-confirmed semiquantitative assessment of kidney fibrosis, and the Seattle Kidney Study, a cohort of patients with common forms of CKD. Ordinal logistic regression and Cox proportional hazards regression models were used to test associations of biomarkers with interstitial fibrosis and tubular atrophy and progression to end-stage kidney disease and death, respectively. Sc/snRNA-seq data confirmed cell-specific expression of biomarker genes in fibroblasts. After multivariable adjustment, higher levels of plasma CDH11, SMOC2, and PEDF and urinary CDH11 and PEDF were significantly associated with increasing severity of interstitial fibrosis and tubular atrophy in the Boston Kidney Biopsy Cohort. In both cohorts, higher levels of plasma and urinary SMOC2 and urinary CDH11 were independently associated with progression to end-stage kidney disease. Higher levels of urinary PEDF associated with end-stage kidney disease in the Seattle Kidney Study, with a similar signal in the Boston Kidney Biopsy Cohort, although the latter narrowly missed statistical significance. Thus, we identified CDH11, SMOC2, and PEDF as promising non-invasive biomarkers of kidney fibrosis.

The major goals of the Kidney Precision Medicine Project (KPMP) are to establish a molecular atlas of the kidney in health and disease and improve our understanding of the molecular drivers of chronic kidney disease and acute kidney injury. In this clinical-pathological-molecular correlation, we describe the case of a 38-year-old woman without any prior history of chronic kidney disease who underwent a research kidney biopsy in the setting of acute kidney injury suspected to be due to non-steroidal anti-inflammatory use following cesarean section delivery. The participant's histopathology was consistent with mild acute tubular injury, without significant interstitial fibrosis or tubular atrophy. This diagnosis was supported by analysis of the glomerular and tubulointerstitial proteomes. The proteomic interrogation revealed a molecular landscape that demonstrated differences in kidney prostaglandin synthesis that may be in response to NSAIDs, as well as signs of intra-renal inflammation and fibrosis that were not evident by histopathology alone.

Kidney involvement is common in patients with systemic lupus erythematosus (SLE). This study investigates the clinical and prognostic characteristics of thrombotic microangiopathy (TMA) compared to class IV lupus nephritis in SLE patients. A retrospective review of patients who underwent kidney biopsy, with a primary diagnosis of SLE and TMA between June 2006 and September 2018 was conducted. Those patients were subsequently compared to patients with class IV lupus nephritis between January 2018 and December 2018. Demographics, laboratory, and serological data at the time of biopsy were abstracted. Among 214 SLE patients records screened, 27 were included in the final analysis. Eight patients had lupus-related TMA without evidence of active lupus nephritis, while 19 patients had class IV lupus nephritis without evidence of TMA. TMA patients had significantly higher lactate dehydrogenase levels (718 ± 499 vs. 264 ± 107.7 U/L, p = 0.009), serum C3 (100.6 ± 39.3 vs. 65.8 ± 27 mg/dL, p = 0.049), white blood cell count (14743.8 ± 7933.3 vs. 5807.9 ± 2053.2 × 10E3/uL, p

Patients undergoing cardiac surgery are placed under intense physiologic stress. Blood and urine biomarkers measured peri-operatively may help identify patients at higher risk for adverse long-term kidney outcomes.We sought to determine independent associations of various biomarkers with development or progression of chronic kidney disease (CKD) following cardiac surgery. In this sub-study of the prospective cohort –TRIBE-AKI Study, we evaluated 613 adult patients undergoing cardiac surgery in Canada in our primary analysis and tested the association of 40 blood and urinary biomarkers with the primary composite outcome of CKD incidence or progression. In those with baseline estimated glomerular filtration rate (eGFR) over 60 mL/min/1.73m2, we defined CKD incidence as a 25% reduction in eGFR and an eGFR under 60. In those with baseline eGFR under 60 mL/min/1.73m2, we defined CKD progression as a 50% reduction in eGFR or eGFR under 15. Results were evaluated in a replication cohort of 310 patients from one study site in the United States. Over a median follow-up of 5.6 years, 172 patients developed the primary outcome. Each log increase in basic fibroblast growth factor (adjusted hazard ratio 1.52 [95% confidence interval 1.19, 1.93]), Kidney Injury Molecule-1 (1.51 [0.98, 2.32]), N-terminal pro–B-type natriuretic peptide (1.19 [1.01, 1.41]), and tumor necrosis factor receptor 1 (1.75 [1.18, 2.59]) were associated with outcome after adjustment for demographic factors, serum creatinine, and albuminuria. Similar results were noted in the replication cohort. Although there was no interaction by acute kidney injury in continuous analysis, mortality was higher in the no acute kidney injury group by biomarker tertile. Thus, elevated post-operative levels of blood biomarkers following cardiac surgery were independently associated with the development of CKD. These biomarkers can provide additional value in evaluating CKD incidence and progression after cardiac surgery.

IntroductionAlthough studies have examined the utility of clinical decision support tools in improving acute kidney injury (AKI) outcomes, no study has evaluated the effect of real-time, personalised AKI recommendations. This study aims to assess the impact of individualised AKI-specific recommendations delivered by trained clinicians and pharmacists immediately after AKI detection in hospitalised patients.Methods and analysisKAT-AKI is a multicentre randomised investigator-blinded trial being conducted across eight hospitals at two major US hospital systems planning to enrol 4000 patients over 3 years (between 1 November 2021 and 1 November 2024). A real-time electronic AKI alert system informs a dedicated team composed of a physician and pharmacist who independently review the chart in real time, screen for eligibility and provide combined recommendations across the following domains: diagnostics, volume, potassium, acid–base and medications. Recommendations are delivered to the primary team in the alert arm or logged for future analysis in the usual care arm. The planned primary outcome is a composite of AKI progression, dialysis and mortality within 14 days from randomisation. A key secondary outcome is the percentage of recommendations implemented by the primary team within 24 hours from randomisation. The study has enrolled 500 individuals over 8.5 months. Two-thirds were on a medical floor at the time of the alert and 17.8% were in an intensive care unit. Virtually all participants were recommended for at least one diagnostic intervention. More than half (51.6%) had recommendations to discontinue or dose-adjust a medication. The median time from AKI alert to randomisation was 28 (IQR 15.8–51.5) min.Ethics and disseminationThe study was approved by the ethics committee of each study site (Yale University and Johns Hopkins institutional review board (IRB) and a central IRB (BRANY, Biomedical Research Alliance of New York). We are committed to open dissemination of the data through clinicaltrials.gov and sharing of data on an open repository as well as publication in a peer-reviewed journal on completion.Trial registration numberNCT04040296.

Introduction: Thrombocytopenia (TCP) is a common finding in patients receiving continuous renal replacement therapy (CRRT). Objective: The purpose of this study was to assess the nature of TCP in patients receiving CRRT. Methods: This is a single-center case-control observational study of 795 patients involving over 166,950 h of delivered CRRT at Johns Hopkins Hospital. Concurrent TCP in patients receiving CRRT was defined as a decrease in platelet count of ≥50% any time within 72 h of initiation of CRRT with strict exclusion criteria. Results: There was a higher incidence of TCP in the cardiac intensive care unit (CICU) (22.5%) compared to medical ICU (MICU) (13.1%). Using logistic regression, the odds of developing concurrent TCP in patients receiving CRRT was 2.46 (95% CI 1.32–3.57, p < 0.05) times higher in the CICU compared with the MICU. There was no difference in the incidence of severe or profound TCP or timing of acute TCP between the CICU and MICU. Conclusion: Safe delivery of dialysis care in the ICU is paramount and creating awareness of potential risks such as concurrent TCP in patients receiving CRRT should be part of this care.

Introduction In patients with systemic lupus erythematosus (SLE) without concurrent active urinary sediment or unexplained acute kidney injury (AKI), current guidelines recommend performing a kidney biopsy in those with at least 500 mg/24-hour (European League Against Rheumatism/European Renal Association-European Dialysis and Transplant Association [EULAR/ERA-EDTA]) or 1000 mg/24-hour (American College of Rheumatology [ACR]) proteinuria. To evaluate the relevance of these indications, we studied histopathologic findings in patients with SLE with proteinuria below these cutoffs. Methods We retrospectively reviewed the clinical, laboratory and histological characteristics of patients with SLE with, Graphical abstract

Background Cardiac markers such as high-sensitivity cardiac troponin T (hs-cTnT) and N-terminal pro-B natriuretic peptide (NTproBNP) are predictors of developing acute kidney injury (AKI) during hospitalization for surgery or revascularization. However, their associations with the long-term risk of AKI in the general population are uncharacterized. Methods We conducted a prospective cohort study in 10 669 participants of the Atherosclerosis Risk in Communities Study (visit 4, 1996–1998, mean age, 63 years, 56% female, 22% black race) to examine the association of plasma concentrations of hs-cTnT and NTproBNP with the incident hospitalization with AKI. We used multivariable Cox regression analysis to estimate hazard ratios (HRs). Results During follow-up, 1907 participants had an incident hospitalization with AKI. Participants with higher concentrations of hs-cTnT had a higher risk of hospitalization with AKI in a graded fashion (adjusted HR, 1.88 [95%CI , 1.59–2.21] for ≥14 ng/L, 1.36 [1.18–1.57] for 9–13 ng/L, and 1.16 [1.03–1.30] for 5-8 ng/L compared to Conclusions In middle-aged to older black and white adults in the community, higher concentrations of hs-cTnT and NTproBNP were robustly associated with an increased risk of hospitalization with AKI. These results suggest the usefulness of hs-cTnT and NT-proBNP to identify people at risk of AKI in the general population.

Study objective Acute kidney injury occurs commonly and is a leading cause of prolonged hospitalization, development and progression of chronic kidney disease, and death. Early acute kidney injury treatment can improve outcomes. However, current decision support is not able to detect patients at the highest risk of developing acute kidney injury. We analyzed routinely collected emergency department (ED) data and developed prediction models with capacity for early identification of ED patients at high risk for acute kidney injury. Methods A multisite, retrospective, cross-sectional study was performed at 3 EDs between January 2014 and July 2017. All adult ED visits in which patients were hospitalized and serum creatinine level was measured both on arrival and again with 72 hours were included. We built machine-learning-based classifiers that rely on vital signs, chief complaints, medical history and active medical visits, and laboratory results to predict the development of acute kidney injury stage 1 and 2 in the next 24 to 72 hours, according to creatinine-based international consensus criteria. Predictive performance was evaluated out of sample by Monte Carlo cross validation. Results The final cohort included 91,258 visits by 59,792 unique patients. Seventy-two–hour incidence of acute kidney injury was 7.9% for stages greater than or equal to 1 and 1.0% for stages greater than or equal to 2. The area under the receiver operating characteristic curve for acute kidney injury prediction ranged from 0.81 (95% confidence interval 0.80 to 0.82) to 0.74 (95% confidence interval 0.74 to 0.75), with a median time from ED arrival to prediction of 1.7 hours (interquartile range 1.3 to 2.5 hours). Conclusion Machine learning applied to routinely collected ED data identified ED patients at high risk for acute kidney injury up to 72 hours before they met diagnostic criteria. Further prospective evaluation is necessary.

Acceptance of organs from acute chemical intoxicated donors remains controversial and outcomes are insufficiently explored. This is a single-center retrospective cohort analysis of 484 patients undergoing deceased donor kidney transplantation (DDKT). We assessed the association of positive urine drug screen before transplantation with cohort statistics, delayed graft function (DGF), and graft outcomes at 2 years. Multiple logistical regression (MLR) analysis was used to assess the odds ratio for DGF. Of 484 random DDKTs performed at our institution between January 2010 and October 2015, 280 deceased kidney donors were current drug users. Mean age was 35.4 (15) years, 39% male, 61% were African Americans, and 38.2% had more than one test positive. The main chemical toxins detectable in donor urine were alcohol, heroin, opioid/methadone, cocaine, marijuana, benzodiazepines, methamphetamine, ecstasy, and LSD. Single and multiple urine chemical toxicology of kidney donors did not have a significant effect on KT outcomes of DGF and graft failure during a median follow-up (P for odds ratios > 0.05). The use of deceased donor kidney grafts from donors with positive urine chemical toxicology may be a worthwhile method of increasing the availability of scarce donor kidney organs as such exposure to illicit drug(s) is not associated with major adverse transplant outcomes.

Background Few studies have investigated the association of magnesium levels with incident peripheral artery disease (PAD) despite emerging evidence of magnesium contributing to vascular calcification. Moreover, no data are available on whether the magnesium–PAD relationship is independent of or modified by kidney function. Methods A cohort of 11 839 participants free of PAD in the Atherosclerosis Risk in Communities Study at Visit 2 (1990–92) was studied. We investigated the association of serum magnesium and other bone–mineral metabolism markers [calcium, phosphorus, intact parathyroid hormone (iPTH) and intact fibroblast growth factor-23] with incident PAD using multivariable Cox proportional hazards regression. Results Over a median of 23 years, there were 471 cases of incident PAD. The hazard ratio for incident PAD in Quartile 1 (1.7 mEq/L) of magnesium was 1.96 (95% confidence interval 1.40–2.74) after adjustment for potential confounders. Lower magnesium levels were associated with greater incidence of PAD, particularly in those with estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2 (n = 11 606). In contrast, the association was largely flat in those with eGFR 65 pg/mL was significantly related to PAD only in those with eGFR Conclusions Lower magnesium was independently associated with incident PAD, but this association was significantly weaker in those with reduced kidney function. In contrast, higher iPTH levels were particularly related to PAD risk in this clinical population.

Objective To determine whether surge conditions were associated with increased mortality. Design Multicenter cohort study. Setting U.S. ICUs participating in STOP-COVID. Patients Consecutive adults with COVID-19 admitted to participating ICUs between March 4 and July 1, 2020. Interventions None Measurements and Main Results The main outcome was 28-day in-hospital mortality. To assess the association between admission to an ICU during a surge period and mortality, we used two different strategies: (1) an inverse probability weighted difference-in-differences model limited to appropriately matched surge and non-surge patients and (2) a meta-regression of 50 multivariable difference-in-differences models (each based on sets of randomly matched surge- and non-surge hospitals). In the first analysis, we considered a single surge period for the cohort (March 23 – May 6). In the second, each surge hospital had its own surge period (which was compared to the same time periods in matched non-surge hospitals). Our cohort consisted of 4342 ICU patients (average age 60.8 [sd 14.8], 63.5% men) in 53 U.S. hospitals. Of these, 13 hospitals encountered surge conditions. In analysis 1, the increase in mortality seen during surge was not statistically significant (odds ratio [95% CI]: 1.30 [0.47-3.58], p = .6). In analysis 2, surge was associated with an increased odds of death (odds ratio 1.39 [95% CI, 1.34-1.43], p Conclusions Admission to an ICU with COVID-19 in a hospital that is experiencing surge conditions may be associated with an increased odds of death. Given the high incidence of COVID-19, such increases would translate into substantial excess mortality.

An understanding of the ethical underpinnings of human subjects research that involves some risk to participants without anticipated direct clinical benefit-such as the kidney biopsy procedure as part of the Kidney Precision Medicine Project (KPMP)-requires a critical examination of the risks as well as the diverse set of countervailing potential benefits to participants. This kind of deliberation has been foundational to the development and conduct of the KPMP. Herein, we use illustrative features of this research paradigm to develop a more comprehensive conceptualization of the types of benefits that may be important to research participants, including respecting pluralistic values, supporting the opportunity to act altruistically, and enhancing benefits to a participant's community. This approach may serve as a model to help researchers, ethicists, and regulators to identify opportunities to better respect and support participants in future research that entails some risk to these participants as well as to improve the quality of research for people with kidney disease.

Background: Kidney function is a crucial determinant of bone-mineral metabolism (BMM); however, the contribution of kidney dysfunction, especially at mild to moderate stages, to vascular calcification remains controversial. Moreover, little is known about whether BMM markers are associated with coronary artery calcification (CAC) and extra-coronary calcification (ECC) beyond kidney function. Methods: In 1935 ARIC participants (age 73-95 years) with no coronary heart disease and data on CAC and ECC at visit 7 (2018-2019), we evaluated estimated glomerular filtration (eGFR) (based on creatinine, cystatin C, and both) and serum BMM markers (calcium, fibroblast growth factor 23, magnesium, parathyroid hormone, and phosphorus) as exposures. The exposures were modeled as weighted averages over ~15 years (visit 1 [1987-89] to visit 5 [2011-13] to allow a lag time for vascular calcification), and the outcome variables were high CAC and ECC (sex-race specific ≥75 th vs. th percentile Agatston score) or any CAC and ECC (Agatston score >0 vs. 0) using multivariable logistic regression. Results: Low eGFR (overall range 30-149 mL/min/1.73m 2 ), regardless of equations, was not robustly associated with high CAC and ECC. Among BMM markers, only higher phosphorus levels, even within the normal range, showed significant associations with high CAC and ECC, independent of kidney function ( Figure ). Considering presence of any calcification, results were generally consistent, although cystatin C-based eGFR 2 was associated with mitral valve calcification (present in 47%) (odds ratio 1.70 [95% CI 1.13, 2.58]). Conclusion: Cumulative exposure to lower eGFR showed weak associations with vascular calcification in community-dwelling older adults. Among BMM markers, phosphorus was most robustly associated with CAC and ECC beyond kidney function. Our results suggest a potential key role of phosphorus in the pathophysiology of vascular calcification.

Since the start of the COVID-19 pandemic, several manifestations of kidney involvement associated with infection of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus have been described, including proteinuria, hematuria, and acute kidney injury. A growing body of literature has explored the risk factors and pathogenesis of COVID-19-associated acute kidney injury (AKI), including direct and indirect mechanisms, as well as early postdischarge outcomes that may result from various manifestations of kidney involvement. In this review, we explore the current state of knowledge of the epidemiology of COVID-19-associated AKI, potential mechanisms and pathogenesis of AKI, and various management strategies for patients in the acute setting. We highlight how kidney replacement therapy for patients with COVID-19-associated AKI has been affected by the increasing demand for dialysis and how the postacute management of patients, including outpatient follow-up, is vitally important. We also review what is presently known about long-term kidney outcomes after the initial recovery from COVID-19. We provide some guidance as to the management of patients hospitalized with COVID-19 who are at risk for AKI as well as for future clinical research in the setting of COVID-19 and the significance of early identification of patients at highest risk for adverse kidney outcomes.

Rationale & Objective Acute kidney injury treated with kidney replacement therapy (AKI-KRT) occurs frequently in critically ill patients with COVID-19. We examined the clinical factors that determine kidney recovery in this population. Study Design Multicenter cohort study. Setting & Participants 4221 adults with COVID-19 not receiving kidney replacement therapy who were admitted to intensive care units at 68 US hospitals with COVID-19 from March 1 to June 22, 2020 (the “ICU cohort”). Among these, 876 developed AKI-KRT after admission to the ICU (the “AKI-KRT subcohort”). Exposure(s) The ICU cohort was analyzed using AKI severity as the exposure. For the AKI-KRT subcohort, exposures included demographics, comorbidities, initial mode of KRT, and markers of illness severity at the time of dialysis initiation. Outcome(s) The outcome for the ICU cohort was estimated glomerular filtration rate (GFR) at hospital discharge. A three-level outcome including death, kidney nonrecovery, and kidney recovery at discharge, was analyzed for the AKI-KRT subcohort. Analytical approach The ICU cohort was characterized using descriptive analyses. The AKI-KRT subcohort was characterized with both descriptive analyses and multinomial logistic regression to assess factors associated with kidney nonrecovery while accounting for death. Results Among a total of 4221 patients in the ICU cohort, 2361 (56%) developed AKI, including 876 (21%) who received KRT. More severe AKI was associated with higher mortality. Among survivors, more severe AKI was associated with an increased rate of kidney nonrecovery and lower kidney function at discharge. Among the 876 patients with AKI-KRT, 588 (67%) died, 95 (11%) had kidney nonrecovery, and 193 (22%) had kidney recovery by the time of discharge. The odds of kidney nonrecovery was greater for lower estimated GFR with odds ratios (ORs) of 2.09 (95% CI, 1.09-4.04), 4.27 (95% CI, 1.99-9.17), and 8.69 (95% CI, 3.07-24.55) for CKD GFR categories 3, 4, and 5, respectively, compared to estimated GFR > 60 mL/min/1.73 m2. Oliguria at the time of KRT initiation was also associated with nonrecovery (OR 2.10 [95% CI, 1.14-3.88] and 4.02 [95% CI, 1.72-9.39] for patients with 50-499 and, Critically ill patients with COVID-19 often develop acute kidney injury (AKI). This study of 4221 patients demonstrated that more severe AKI was associated with greater in-hospital mortality and poorer kidney function at hospital discharge. Among the 876 patients who required dialysis for AKI, almost two-thirds died. Among those who survived to discharge, about two-thirds recovered kidney function and were discharged without the need for dialysis. Lower baseline kidney function and reduced urine output were associated with non-recovery of kidney function. Identification of such predictors is important in assessing prognosis among these critically ill patients and has implications for clinical care of individuals critically ill with COVID-19.

This chapter discusses the continued high prevalence of renal disease in persons with HIV and the broad pathologic spectrum of renal disease, including medication-induced renal injury. It also allows the learner to understand the importance of screening and monitoring people with HIV for chronic kidney disease. Other topics discussed are the indications for nephrology referral and renal biopsy and potential targets of intervention for HIV-associated renal diseases. Treatment options for people with HIV who have end-stage renal disease, including dialysis and solid organ transplant, are also covered.

PURPOSE OF REVIEW: Serum creatinine and urine output continue to be the mainstays of diagnosis of acute kidney injury, though both of these measures have significant limitations, especially in acutely hospitalized patients. Biomarkers in both blood and urine have been studied extensively in the research setting and are on the verge of clinical practice to improve diagnosis of AKI. RECENT FINDINGS: Blood and urine biomarkers can be localized to specific areas or functions within the nephron. Biomarkers can help to characterize glomerular or tubular function; glomerular, tubular, or interstitial injury; inflammation; or repair. Further, biomarkers can improve diagnosis of AKI in various clinical settings including acute interstitial nephritis, acute tubular injury, and hepatorenal syndrome, and cardiorenal syndrome. SUMMARY: Biomarkers are becoming more prevalent in both research and getting close to clinical use. Both blood and urine biomarkers can help to localize impairment in nephron health by either location or function within the nephron and among various etiologies of AKI.

BACKGROUND Assessment of chronic kidney disease (CKD) risk after acute kidney injury (AKI) is based on limited markers primarily reflecting glomerular function. We evaluated markers of cell integrity (EGF) and inflammation (monocyte chemoattractant protein-1, MCP-1) for predicting long-term kidney outcomes after cardiac surgery. METHODS We measured EGF and MCP-1 in postoperative urine samples from 865 adults who underwent cardiac surgery at 2 sites in Canada and the United States and assessed EGF and MCP-1’s associations with the composite outcome of CKD incidence or progression. We used single-cell RNA-Seq (scRNA-Seq) of AKI patient biopsies to perform transcriptomic analysis of programs corregulated with the associated genes. RESULTS Over a median (IQR) follow-up of 5.8 (4.2–7.1) years, 266 (30.8%) patients developed the composite CKD outcome. Postoperatively, higher levels of urinary EGF were protective and higher levels of MCP-1 were associated with the composite CKD outcome (adjusted HR 0.83, 95% CI 0.73–0.95 and 1.10, 95% CI 1.00–1.21, respectively). Intrarenal scRNA-Seq transcriptomes in patients with AKI-defined cell populations revealed concordant changes in EGF and MCP-1 levels and underlying molecular processes associated with loss of EGF expression and gain of CCL2 (encoding MCP-1) expression. CONCLUSION Urinary EGF and MCP-1 were each independently associated with CKD after cardiac surgery. These markers may serve as noninvasive indicators of tubular damage, supported by tissue transcriptomes, and provide an opportunity for novel interventions in cardiac surgery. TRIAL REGISTRATION ClinicalTrials.gov NCT00774137. FUNDING The NIH funded the TRIBE-AKI Consortium and Kidney Precision Medicine Project. Yale O’Brien Kidney Center, American Heart Association, Patterson Trust Fund, Dr. Adam Linton Chair in Kidney Health Analytics, Canadian Institutes of Health Research, ICES, Ontario Ministry of Health and Long-Term Care, Academic Medical Organization of Southwestern Ontario, Schulich School of Medicine & Dentistry, Western University, Lawson Health Research Institute, Chan Zuckerberg Initiative Human Cell Atlas Kidney Seed Network.

Variation in hospital mortality has been described for coronavirus disease 2019 (COVID-19), but the factors that explain these differences remain unclear.Our objective was to utilize a large, nationally representative dataset of critically ill adults with COVID-19 to determine which factors explain mortality variability.In this multicenter cohort study, we examined adults hospitalized in intensive care units with COVID-19 at 70 United States hospitals between March and June 2020. The primary outcome was 28-day mortality. We examined patient-level and hospital-level variables. Mixed-effects logistic regression was used to identify factors associated with interhospital variation. The median odds ratio (OR) was calculated to compare outcomes in higher- vs. lower-mortality hospitals. A gradient boosted machine algorithm was developed for individual-level mortality models.A total of 4,019 patients were included, 1537 (38%) of whom died by 28 days. Mortality varied considerably across hospitals (0-82%). After adjustment for patient- and hospital-level domains, interhospital variation was attenuated (OR decline from 2.06 [95% CI, 1.73-2.37] to 1.22 [95% CI, 1.00-1.38]), with the greatest changes occurring with adjustment for acute physiology, socioeconomic status, and strain. For individual patients, the relative contribution of each domain to mortality risk was: acute physiology (49%), demographics and comorbidities (20%), socioeconomic status (12%), strain (9%), hospital quality (8%), and treatments (3%).There is considerable interhospital variation in mortality for critically ill patients with COVID-19, which is mostly explained by hospital-level socioeconomic status, strain, and acute physiologic differences. Individual mortality is driven mostly by patient-level factors. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Summary: Many US states published crisis standards of care (CSC) guidelines for allocating scarce critical care resources during the COVID-19 pandemic. However, the performance of these guidelines in maximizing their population benefit has not been well tested. In 2,272 adults with COVID-19 requiring mechanical ventilation drawn from the Study of the Treatment and Outcomes in Critically Ill Patients with COVID-19 (STOP-COVID) multicenter cohort, we test the following three approaches to CSC algorithms: Sequential Organ Failure Assessment (SOFA) scores grouped into ranges, SOFA score ranges plus comorbidities, and a hypothetical approach using raw SOFA scores not grouped into ranges. We find that area under receiver operating characteristic (AUROC) curves for all three algorithms demonstrate only modest discrimination for 28-day mortality. Adding comorbidity scoring modestly improves algorithm performance over SOFA scores alone. The algorithm incorporating comorbidities has modestly worse predictive performance for Black compared to white patients. CSC algorithms should be empirically examined to refine approaches to the allocation of scarce resources during pandemics and to avoid potential exacerbation of racial inequities.

Chronic kidney disease (CKD) and acute kidney injury (AKI) are common, heterogeneous, and morbid diseases. Mechanistic characterization of CKD and AKI in patients may facilitate a precision medicine approach to prevention, diagnosis, and treatment. The Kidney Precision Medicine Project aims to ethically and safely obtain kidney biopsies from participants with CKD or AKI, create a reference kidney atlas, and characterize disease subgroups to stratify patients based on molecular features of disease, clinical characteristics, and associated outcomes. An additional aim is to identify critical cells, pathways, and targets for novel therapies and preventive strategies. This project is a multicenter prospective cohort study of adults with CKD or AKI who undergo a protocol kidney biopsy for research purposes. This investigation focuses on kidney diseases that are most prevalent and therefore substantially burden the public health, including CKD attributed to diabetes or hypertension and AKI attributed to ischemic and toxic injuries. Reference kidney tissues (for example, living kidney donor biopsies) will also be evaluated. Traditional and digital pathology will be combined with transcriptomic, proteomic, and metabolomics analysis of the kidney tissue as well as deep clinical phenotyping for supervised and unsupervised subgroup analysis and systems biology analysis. Participants will be followed prospectively for ten years to ascertain clinical outcomes. Cell types, locations, and functions will be characterized in health and disease in an open, searchable, online kidney tissue atlas. All data from the Kidney Precision Medicine Project will be made readily available for broad use by scientists, clinicians, and patients.

Rationale & Objective Underlying kidney disease is an emerging risk factor for more severe COVID-19 illness. We examined the clinical courses of critically ill COVID-19 patients with and without pre-existing kidney disease and investigated the association between degree of underlying kidney disease and in-hospital outcomes. Study Design Retrospective cohort study Settings & Participants 4,264 critically ill COVID-19 patients (143 dialysis patients, 521 chronic kidney disease [CKD] patients, and 3,600 patients without CKD) admitted to ICUs at 68 hospitals in the United States. Predictor(s) Presence (versus absence) of pre-existing kidney disease Outcome(s) In-hospital mortality (primary); respiratory failure, shock, ventricular arrhythmia/ cardiac arrest, thromboembolic event, major bleed, and acute liver injury (secondary) Analytical Approach We used standardized differences to compare patient characteristics (values >0.10 indicate a meaningful difference between groups) and multivariable adjusted Fine and Gray survival models to examine outcome associations. Results Dialysis patients had a shorter time from symptom onset to ICU admission compared to other groups (median [quartile 1-quartile 3] days: 4 [2-9] for dialysis patients; 7 [3-10] for CKD patients; 7 [4-10] for patients without pre-existing kidney disease). More dialysis patients (25%) reported altered mental status than those with CKD (20%, standardized difference = 0.12) and no kidney disease (12%, standardized difference = 0.36). Half of dialysis and CKD patients died within 28-days of ICU admission versus 35% of patients without pre-existing kidney disease. Compared to patients without pre-existing kidney disease, dialysis patients had a higher risk of 28-day in-hospital death (adjusted HR 1.41; 95% CI 1.09, 1.81), while patients with CKD had an intermediate risk (adjusted HR 1.25; 95% CI 1.08, 1.44). Limitations Potential residual confounding Conclusions Findings highlight the high mortality of individuals with underlying kidney disease and severe COVID-19, underscoring the importance of identifying safe and effective COVID-19 therapies for this vulnerable population., Individuals with underlying kidney disease may be particularly vulnerable to severe COVID-19 illness, marked by multi-system organ failure, thrombosis, and a heightened inflammatory response. Among 4,264 critically ill adults with COVID-19 admitted to 68 intensive care units across the U.S., we found that both chronic kidney disease and dialysis patients had a ∼50% 28-day in-hospital mortality rate. Patients with underlying kidney disease had higher in-hospital mortality than patients without kidney disease, with patients on maintenance dialysis having the highest risk. As evidenced by differences in symptoms and clinical trajectories, patients with pre-existing kidney disease may have unique susceptibility to COVID-19-related complications which warrants additional study and special consideration in the pursuit and development of targeted therapies.

Hypercoagulability may be a key mechanism of death in patients with COVID-19. This cohort study evaluated the incidence of venous thromboembolism and major bleeding in critically ill patients with COVID-19 and examined the observational effect of early therapeutic anticoagulation on survival., Visual Abstract. Early Anticoagulation in COVID-19 Hypercoagulability may be a key mechanism of death in patients with COVID-19. This cohort study evaluated the incidence of venous thromboembolism and major bleeding in critically ill patients with COVID-19 and examined the observational effect of early therapeutic anticoagulation on survival. Visual Abstract. Early Anticoagulation in COVID-19 Hypercoagulability may be a key mechanism of death in patients with COVID-19. This cohort study evaluated the incidence of venous thromboembolism and major bleeding in critically ill patients with COVID-19 and examined the observational effect of early therapeutic anticoagulation on survival., Background: Hypercoagulability may be a key mechanism of death in patients with coronavirus disease 2019 (COVID-19). Objective: To evaluate the incidence of venous thromboembolism (VTE) and major bleeding in critically ill patients with COVID-19 and examine the observational effect of early therapeutic anticoagulation on survival. Design: In a multicenter cohort study of 3239 critically ill adults with COVID-19, the incidence of VTE and major bleeding within 14 days after intensive care unit (ICU) admission was evaluated. A target trial emulation in which patients were categorized according to receipt or no receipt of therapeutic anticoagulation in the first 2 days of ICU admission was done to examine the observational effect of early therapeutic anticoagulation on survival. A Cox model with inverse probability weighting to adjust for confounding was used. Setting: 67 hospitals in the United States. Participants: Adults with COVID-19 admitted to a participating ICU. Measurements: Time to death, censored at hospital discharge, or date of last follow-up. Results: Among the 3239 patients included, the median age was 61 years (interquartile range, 53 to 71 years), and 2088 (64.5%) were men. A total of 204 patients (6.3%) developed VTE, and 90 patients (2.8%) developed a major bleeding event. Independent predictors of VTE were male sex and higher D-dimer level on ICU admission. Among the 2809 patients included in the target trial emulation, 384 (11.9%) received early therapeutic anticoagulation. In the primary analysis, during a median follow-up of 27 days, patients who received early therapeutic anticoagulation had a similar risk for death as those who did not (hazard ratio, 1.12 [95% CI, 0.92 to 1.35]). Limitation: Observational design. Conclusion: Among critically ill adults with COVID-19, early therapeutic anticoagulation did not affect survival in the target trial emulation. Primary Funding Source: None.

Kidney involvement is common in coronavirus disease-2019 (COVID-19), and our understanding of the effects of COVID-19 on short- and long-term kidney outcomes has evolved over the course of the pandemic. Initial key questions centered on the spectrum and degree of acute kidney injury (AKI) in patients hospitalized with severe COVID-19. Investigators worldwide have explored the association between COVID-19-associated AKI and short-term outcomes, including inpatient mortality and disease severity. Even as treatments evolved, vaccinations were developed, and newer viral variants arose, subsets of patients were identified as at continued high risk for major adverse kidney outcomes. In this review, we explore key topics of continued relevance including the following: (1) a comparison of COVID-19-associated AKI with AKI developing in other clinical settings; (2) the ongoing controversy over kidney tropism in the setting of COVID-19 and the potential for competitive binding of the severe acute respiratory syndrome coronavirus 2 virus with angiotensin converting enzyme-2 to prevent viral cell entry; and (3) the identification of high-risk patients for adverse outcomes to inform long-term outpatient management. Patients at particularly high risk for adverse kidney outcomes include those with APOL1 high-risk genotype status. Biomarkers of injury, inflammation, tubular health, and repair measured in both the blood and urine may hold prognostic significance.

The pandemic of coronavirus disease 2019 (CoVID-19) has been an unprecedented period. The disease afflicts multiple organ systems, with acute kidney injury (AKI) a major complication in seriously ill patients. The incidence of AKI in patients with CoVID-19 is variable across numerous international studies, but the high incidence of AKI and its associated worse outcomes in the critical care setting are a consistent finding. A multitude of patterns and mechanisms of AKI have been elucidated, and novel strategies to address shortage of renal replacement therapy equipment have been implemented. The disease also has had consequences on longitudinal management of patients with chronic kidney disease and end stage kidney disease. Kidney transplant recipients may be especially susceptible to CoVID-19 as a result of immunosuppression, with preliminary studies demonstrating high mortality rates. Increased surveillance of disease with low threshold for testing and adjustment of immunosuppression regimen during acute periods of illness have been recommended.

We present here an evidence-based review of the utility, timing, and indications for laboratory test use in the domains of inflammation, cardiology, hematology, nephrology and co-infection for clinicians managing the care of hospitalized COVID-19 patients. Levels of IL-6, CRP, absolute lymphocyte count, neutrophils and neutrophil-to-lymphocyte ratio obtained upon admission may help predict the severity of COVID-19. Elevated lactate dehydrogenase, ferritin, aspartate aminotransferase, and ᴅ-dimer are associated with severe illness and mortality. Elevated cardiac troponin at hospital admission can alert clinicians to patients at risk for cardiac complications. Elevated proBNP may help distinguish a cardiac complication from noncardiac etiologies. Evaluation for co-infection is typically unnecessary in nonsevere cases but is essential in severe COVID-19, intensive care unit patients, and immunocompromised patients.

The advent of personalized medicine has driven the development of novel approaches for obtaining detailed cellular and molecular information from clinical tissue samples. Tissue cytometry is a promising new technique that can be used to enumerate and characterize each cell in a tissue and, unlike flow cytometry and other single-cell techniques, does so in the context of the intact tissue, preserving spatial information that is frequently crucial to understanding a cell’s physiology, function, and behavior. However, the wide-scale adoption of tissue cytometry as a research tool has been limited by the fact that published examples utilize specialized techniques that are beyond the capabilities of most laboratories. Here we describe a complete and accessible pipeline, including methods of sample preparation, microscopy, image analysis, and data analysis for large-scale three-dimensional tissue cytometry of human kidney tissues. In this workflow, multiphoton microscopy of unlabeled tissue is first conducted to collect autofluorescence and second-harmonic images. The tissue is then labeled with eight fluorescent probes, and imaged using spectral confocal microscopy. The raw 16-channel images are spectrally deconvolved into 8-channel images, and analyzed using the Volumetric Tissue Exploration and Analysis (VTEA) software developed by our group. We applied this workflow to analyze millimeter-scale tissue samples obtained from human nephrectomies and from renal biopsies from individuals diagnosed with diabetic nephropathy, generating a quantitative census of tens of thousands of cells in each. Such analyses can provide useful insights that can be linked to the biology or pathology of kidney disease. The approach utilizes common laboratory techniques, is compatible with most commercially-available confocal microscope systems and all image and data analysis is conducted using the VTEA image analysis software, which is available as a plug-in for ImageJ. Tissue cytometry is a promising new microscopy technique that can be used to enumerate and characterize each cell in a tissue. Here the authors describe a complete and accessible pipeline, including methods of sample preparation, microscopy, image analysis, and data analysis for large-scale three-dimensional tissue cytometry of human kidney tissues.

BackgroundAnkle-brachial index (ABI), the first-line diagnostic test for peripheral artery disease, can be falsely elevated when ankle arteries are incompressible, showing a J-shaped association with mortality. In this situation, toe-brachial index (TBI) is the recommended test. However, whether TBI provides additional prognostic information beyond ABI in patients on hemodialysis is unknown.MethodsIn this retrospective cohort study of 247 Japanese prevalent hemodialysis patients (mean age 66.8 [SD 11.6] years), we evaluated mortality (116 deaths over a median follow-up of 5.2 years) related to quartiles of ABI and TBI, as well as three categories of low ABI (≤0.9), normal/high ABI (> 0.9) + low TBI (≤0.6), and normal/high ABI + normal TBI (> 0.6) using multivariable Cox models.ResultsABI showed a J-shaped association with mortality (adjusted hazard ratio 2.72 [95% CI, 1.52–4.88] in the lowest quartile and 1.59 [95% CI, 0.87–2.90] in the highest quartile vs. the second highest). Lower TBI showed a potentially dose-response association with mortality (e.g., adjusted hazard ratios 2.63 [95% CI, 1.36–5.12] and 2.89 [95% CI, 1.49–5.61] in the lowest two quartiles vs. the highest). When three categories by both ABI and TBI were analyzed, those with low ABI (≤0.9) experienced the highest risk followed by normal/high ABI (> 0.9) + low TBI (≤0.6). Among patients with normal/high ABI (> 0.9), the increased mortality risk in individuals with low TBI (≤0.6) compared to those with normal TBI (> 0.6) were significant (adjusted hazard ratio 1.84 [95% CI, 1.12–3.02]).ConclusionsLower TBI was independently associated with mortality in patients on hemodialysis and has the potential to classify mortality risk in patients with normal/high ABI. Our results support the importance of evaluating TBI in addition to ABI in this clinical population.

Case Description A 62-year-old man with a past medical history of diabetes mellitus presented to the hospital with shortness of breath and nonproductive cough. His vital signs revealed the following: BP, 83/52 mm Hg; heart rate, 119 beats per minute; respiratory rate, 28 breaths/min; oxygen saturation, 60% on room air; temperature, 103.3°F. Cardiopulmonary examination demonstrated sinus tachycardia and bilateral crackles. Initial basic laboratory values were as follows: white blood cells, 13.6 K/mm3 with neutrophil predominance; hemoglobin, 11.8 g/dl; platelets, 264 K/mm3; sodium, 135 mmol/L; potassium, 5.5 mmol/L; chloride, 97 mmol/L; bicarbonate, 21 mmol/L; BUN, 44 mg/dl; serum creatinine, 3.47 mg/dl; calcium, 7.4 mg/dl; albumin, 2.4 g/dl; normal liver function tests; lactate, 2.7 mmol/L; C-reactive protein, >300 mg/dl; D-dimer, 13,900 ng/ml; fibrinogen, 598 mg/dl; ferritin, 392 ng/ml; partial thromboplastin time, 73 seconds. Urinalysis was negative for hematuria or proteinuria. Urine sediment …

Background Sodium bicarbonate, in the form of baking soda, is widely used as a home remedy, and as an additive for personal and household cleaning products. Its toxicity has previously been reported following oral ingestion in the setting of dyspepsia. However, its use as a non-ingested agent, like a toothpaste additive, has not been reported as a potential cause of toxicity. Case presentation We are reporting a case of an 80-year-old woman who presented with chronic metabolic alkalosis and hypokalemia secondary to exogenous alkali exposure from baking soda as a toothpaste additive, which might have represented an underreported ingestion of the substance. Conclusions Considering that one teaspoon of baking soda provides approximately 59 m-equivalents (mEq) of bicarbonate, specific questioning on its general use should be pursued in similar cases of chloride resistant metabolic alkalosis.

A 39-year-old woman with a history of menorrhagia who underwent laparoscopic hysterectomy presented to the emergency department 4 days after surgery with abdominal pain and distention. Her vitals revealed the following: blood pressure 98/62 mm Hg, heart rate 110 beats/minute, oxygen saturation 99% on room air, and temperature 37.1 °C. Initial basic laboratory values were as follows: white blood counts 18.0×109/L with neutrophil predominance, hemoglobin 15.2 g/dl, platelets 190×109/L, sodium 134 mmol/L, potassium 4.9 mmol/L, chloride 101 mmol/L, bicarbonate 17 mmol/L, BUN 45 mg/dl (9–24), serum creatinine 7.4 mg/dl, calcium 9.0 mg/dl, albumin 3.7 g/dl, aspartate aminotransferase 20 U/L, alanine aminotransferase 25 U/L, alkaline phosphatase 90 U/L, total bilirubin 0.6 mg/dl, lipase 62 U/L, and lactate 2.4 mmol/L. Urinalysis was remarkable …

Introduction The term “acute tubular injury” (ATI) represents histopathologic renal tubular injury and often manifests clinically as acute kidney injury (AKI). Studies systematically summarizing the clinical presentation and histological changes in human ATI are limited. Methods We used a comprehensive search strategy to search human studies of ATI from 1936 to July 2019. We extracted study characteristics, clinical characteristics, and histologic descriptions of ATI by bright field, immunofluorescence, electron microscopy, and immunohistochemistry. We compared ATI histology as a function of tissue procurement type, timing, and etiologies. Results We included 292 studies comprising a total of 1987 patients. The majority of studies (222 of 292, 76%) were single-center case reports. The mean age of included patients was 47 years. In native kidney biopsy cases, baseline, peak, and latest creatinine were 1.3 mg/dl, 7.19 mg/dl, and 1.85 mg/dl respectively, and biopsy was performed mostly after peak creatinine (86.7%, 391 of 451). We identified 16 histologic descriptions of tubular injury, including tubular cell sloughing (115 of 292, 39.4%), tubular epithelial flattening/simplification (110 of 292, 37.7%), tubular dilatation (109 of 292, 37.3%), and tubular cell necrosis (93 of 292, 31.8%). There was no difference in tubular injury histology among different tissue procurement types (native kidney biopsy, transplant kidney biopsy, and autopsy), among different etiologies, or between different tissue procurement timing (before or after creatinine peaks in native kidneys). Electron microscopy and immunohistochemistry were used in a minority of studies. Conclusion ATI manifests with diverse histologic changes. Efforts to establish protocols to harmonize biopsy practices, to handle kidney biopsy for tissue interrogation, and to report results across clinical practice are needed to improve our understanding of this complex disease., Graphical abstract