Editor’s Note: We asked authors of Original Investigations to provide short plain-language summaries that would briefly summarize what inspired their study, the basic approach taken, what was learned, and why it matters. We hope our readers will find this valuable in helping them keep up with the latest research in the field of nephrology. From the December 2020 issue:   

Community Racial Composition and Hospitalization Among Patients Receiving In-Center Hemodialysis by Ladan Golestaneh et al

From the authors: There are few explanations for the variability in hospitalization rates across the United States among patients receiving hemodialysis. We studied the independent association of community racial composition with rates of hospitalization among patients receiving maintenance hemodialysis within the Dialysis Outcomes and Practice Patterns Study (DOPPS). Community racial composition was obtained from Census Bureau data for the zip codes in which the 4,567 study patients were treated. We found that patients receiving hemodialysis in communities with more Black residents were at higher risk for hospitalization after controlling for age, comorbid conditions, and adherence to hemodialysis treatments. We could not determine the underlying factors that are driving this higher hospitalization risk, which should be the focus of future studies.

DOI: 10.1053/j.ajkd.2020.05.019

Editorial: “Place, Not Race”: A Focus on Neighborhood as a Risk Factor for Hospitalizations in Patients Receiving Maintenance Hemodialysis by Nwamaka D Eneanya and Deidra C Crews [FREE] 

The Difference Between Cystatin C– and Creatinine-Based Estimated GFR and Associations With Frailty and Adverse Outcomes: A Cohort Analysis of the Systolic Blood Pressure Intervention Trial (SPRINT) by O Alison Potok n et al 

From the authors: The difference between cystatin C– and creatinine-based estimated glomerular filtration rates (eGFRs) contains important clinical information. It is common to see clinic patients whose eGFRs using creatinine and cystatin C levels differ by >15 mL/min/1.73 m2. We surmised that these differences, usually overlooked in favor of a combined eGFR, carry important information beyond their use as GFR estimates. We examined the intraindividual difference in eGFRs using cystatin C versus creatinine level (eGFRDiff) and found that eGFRDiff may hold prognostic information: a negative eGFRDiff at any level of kidney function was associated with higher risk for frailty, cardiovascular disease, and death. We speculate that this may be due to non–GFR-related creatinine and cystatin C correlates and suggest that eGFRDiff may represent a tool to improve our ability to identify individuals at high risk for these outcomes.

DOI: 10.1053/j.ajkd.2020.05.017

Editorial: Differences Between Cystatin C– and Creatinine-Based Estimated GFR—Early Evidence of a Clinical Marker for Frailty by Mara McAdams-DeMarco et al [FREE] 

Albuminuria and Estimated GFR as Risk Factors for Dementia in Midlife and Older Age: Findings From the ARIC Study by Johannes B Scheppach et al 

From the authors: To understand chronic kidney disease as a risk factor for dementia in different age groups, we measured glomerular filtration rate using different biomarkers and albuminuria in participants of the Atherosclerosis Risk in Communities (ARIC) Study at 2 different time points. The participants, who were aged 54 to 74 years at the first and 70 to 90 years at the second time point, were then observed over several years. We demonstrated that elevated urinary albumin excretion was similarly associated with an increased risk for dementia in both these age groups. In addition, estimates of kidney function based on β2-microglobulin and cystatin C levels may also be associated with dementia, whereas more traditional estimates of kidney function based on serum creatinine level were not.

DOI: 10.1053/j.ajkd.2020.03.015

Outcomes Following Ischemic Stroke in Older Patients With CKD Stages 4 and 5: A Retrospective Cohort Study by James B Wetmore et al

From the authors: We studied whether an ischemic stroke “hastens” the time to death or incident kidney failure in patients with advanced chronic kidney disease. Using Medicare data, we matched patients who experienced an ischemic stroke to similar patients who did not. For patients with stage 5 chronic kidney disease who experienced a stroke, death or incident kidney failure occurred an average of 6.5 months sooner than for patients who did not experience a stroke; death, irrespective of kidney failure, occurred about 2 years sooner. Patients and their physicians should understand that a stroke likely puts them at increased risk for death or need for dialysis and should consider this when discussing plans to potentially transition to dialysis.

DOI: 10.1053/j.ajkd.2020.03.021

Outpatient Interventions for Managing Acute Complications of Chronic Diseases: A Scoping Review and Implications for Patients With CKD by Meghan J Elliott et al 

From the authors: Patients with chronic kidney disease may experience urgent health issues related to their kidney disease, such as high blood potassium levels. Although options are available to treat complications of other chronic diseases, such as heart failure, in the community, it is not known to what extent similar programs exist for treating complications of chronic kidney disease. We reviewed research publications in the medical literature describing outpatient urgent-care strategies for patients living with 5 chronic diseases, including chronic kidney disease. Of the 57 different programs we identified, none was specific to those with chronic kidney disease or kidney failure. In this report, we summarize identified programs and provide examples of how they could be adapted and tested to provide urgent kidney disease–related care.

DOI: 10.1053/j.ajkd.2020.04.006

Real-Time Prediction of Acute Kidney Injury in Hospitalized Adults: Implementation and Proof of Concept by Ugochukwu Ugwuowo et al [FREE until Feb 1, 2021] 

From the authors: For real-time prediction of acute kidney injury (AKI), we previously developed a statistical model to predict AKI in hospitalized patients. In this study, we show how we were able to incorporate that model into the electronic health record of a large tertiary-care health center. We additionally describe the characteristics of patients identified as being at elevated risk for AKI by the model and their clinical outcomes.

DOI: 10.1053/j.ajkd.2020.05.003

Physical Performance Testing in Kidney Transplant Candidates at the Top of the Waitlist by Xingxing S Cheng et al [Open Access]

From the authors: Less physically robust patients on the kidney transplant waitlist have worse outcomes than their more physically robust counterparts. In this study, we applied 2 tools commonly used by physical therapists, the 6-minute walk test and the sit-to-stand test, to assess patients on the kidney transplant waitlist. Among 305 patients followed up for at least 1 year, patients who did better on the 2 tests were less likely to die or be removed from the waitlist and more likely to receive a transplant. These findings suggest the importance of future studies of physical therapy or other interventions aimed at improving physical performance to improve outcomes for patients awaiting kidney transplantation.

DOI: 10.1053/j.ajkd.2020.04.009

Neutrophil Gelatinase-Associated Lipocalin Measured on Clinical Laboratory Platforms for the Prediction of Acute Kidney Injury and the Associated Need for Dialysis Therapy: A Systematic Review and Meta-analysis by Christian Albert et al 

From the authors: This meta-analysis provides neutrophil gelatinase-associated lipocalin (NGAL) cutoff concentrations for kidney risk prediction. Recent practice guidelines for acute kidney injury (AKI) renewed the importance of the earliest possible detection of AKI and adjustment of treatment accordingly. Literature-based meta-analysis revealed that the predictive value of NGAL measured on clinical laboratory platforms may improve the prediction of AKI risk. NGAL cutoff concentrations in clinical settings have not been sufficient. We performed an individual-study-data meta-analysis that demonstrated results similar to the literature-based meta-analysis regarding NGAL’s discriminative ability. Using an individual-study-data meta-analysis that incorporated confounding variables enabled derivation of cutoff concentrations for NGAL to identify patients at risk for severe stages of AKI, including the associated need for dialysis. Notwithstanding the heterogeneity of clinical context, urinary and plasma concentrations of NGAL may enable identification of patients at high risk for AKI in clinical research and practice.

DOI: 10.1053/j.ajkd.2020.05.015

This month’s Special Report:

Drug Development in Kidney Disease: Proceedings From a Multistakeholder Conference by Daniel L Edmonston et al  

From the authors: The unexpected kidney benefits observed with sodium/glucose cotransporter 2 inhibitors may herald a renaissance of drug development in kidney disease. This recent progress highlights the need to further promote and stimulate research and development of promising therapies that may ameliorate the morbidity and mortality associated with kidney disease. This article reviews key topics discussed at a conference convened by the Duke Clinical Research Institute in April 2019, including the utility of interconnected data and site research networks, surrogate end points, pragmatic and adaptive trial designs, the promising uses of real-world data, and methods to improve the generalizability of trial results and uptake of approved drugs for kidney-related diseases.

DOI: 10.1053/j.ajkd.2020.05.026

On the Cover: Thomas Sheraton, an 18th century English furniture designer, is known for elegant chair designs that incorporate multiple veneers and wood species, and strong, well-proportioned geometric forms. We chose to depict Sheraton chairs on this month’s cover as a symbolic representation of methods to evaluate health status such as the 60-second sit-to-stand (STS) test. In this issue of AJKD, Cheng et al applied two tools commonly used to assess frailty, the 6-minute walk and the STS test, to evaluate patients on the kidney transplant wait list and found that patients who performed best on these tests were less likely to die or be removed from the wait list and more likely to receive a transplant.

The illustration “Chairs, by Sheraton”, by Frederick Litchfield fromIllustrated History of Furniture, From the Earliest to the Present Time, was released into the public domain and is available via Wikimedia Commons

Special Collection: Acute Kidney Injury

This special collection on AKI includes articles ranging from tools for predicting of AKI, to epidemiologic studies, to biomarkers, among others. Each article in its own way helps to advance the understanding of AKI and improve the care of patients with it. All articles in the collection are freely available until February 1, 2021.