Impact of AKI on Urinary Protein Excretion: Analysis of Two Prospective Cohorts

Genome-Wide Association Study of Hospitalized Patients and Acute Kidney Injury

Acute kidney injury (AKI) is a common and devastating complication of hospitalization. Here, we identified genetic loci associated with AKI in patients hospitalized between 2002-2019 in the Million Veteran Program and data from Vanderbilt University Medical Center's BioVU. AKI was defined as meeting a modified KDIGO Stage1 or more for two or more consecutive days or kidney replacement therapy. Control individuals were required to have one or more qualifying hospitalization without AKI and no evidence of AKI during any other observed hospitalizations. Genome-wide association studies (GWAS), stratified by race, adjusting for sex, age, baseline estimated glomerular filtration rate (eGFR), and the top ten principal components of ancestry were conducted. Results were meta-analyzed using fixed effects models. In total, there were 54,488 patients with AKI and 138,051 non-AKI individuals included in the study. Two novel loci reached genome-wide significance in the meta-analysis: rs11642015 near the FTO locus on chromosome 16 (obesity traits) (odds ratio 1.07 (95% confidence interval, 1.05-1.09)) and rs4859682 near the SHROOM3 locus on chromosome 4 (glomerular filtration barrier integrity) (odds ratio 0.95 (95% confidence interval, 0.93-0.96)). These loci colocalized with previous studies of kidney function, and genetic correlation indicated significant shared genetic architecture between AKI and eGFR. Notably, the association at the FTO locus was attenuated after adjustment for BMI and diabetes, suggesting that this association may be partially driven by obesity. Both FTO and the SHROOM3 loci showed nominal evidence of replication from diagnostic-code-based summary statistics from UK Biobank, FinnGen, and Biobank Japan. Thus, our large GWA meta-analysis found two loci significantly associated with AKI suggesting genetics may explain some risk for AKI.

Acute kidney injury in patients with cirrhosis: Acute Disease Quality Initiative (ADQI) and International Club of Ascites (ICA) joint multidisciplinary consensus meeting

Patients with cirrhosis are prone to developing acute kidney injury (AKI), a complication associated with a markedly increased in-hospital morbidity and mortality, along with a risk of progression to chronic kidney disease. Whereas patients with cirrhosis are at increased risk of developing any phenotype of AKI, hepatorenal syndrome (HRS), a specific form of AKI (HRS-AKI) in patients with advanced cirrhosis and ascites, carries an especially high mortality risk. Early recognition of HRS-AKI is crucial since administration of splanchnic vasoconstrictors may reverse the AKI and serve as a bridge to liver transplantation, the only curative option. In 2023, a joint meeting of the International Club of Ascites (ICA) and the Acute Disease Quality Initiative (ADQI) was convened to develop new diagnostic criteria for HRS-AKI, to provide graded recommendations for the work-up, management and post-discharge follow-up of patients with cirrhosis and AKI, and to highlight priorities for further research.

Posthospital Multidisciplinary Care for AKI Survivors: A Feasibility Pilot

Rationale & Objective

Innovative models are needed to address significant gaps in kidney care follow-up for acute kidney injury (AKI) survivors.

Study Design

This quasi-experimental pilot study reports the feasibility of the AKI in Care Transitions (ACT) program, a multidisciplinary approach to AKI survivor care based in the primary care setting.

Setting & Participants

The study included consenting adults with stage 3 AKI discharged home without dialysis.

Interventions

The ACT intervention included predischarge education from nurses and coordinated postdischarge follow-up with a primary care provider and pharmacist within 14 days. ACT was implemented in phases (Usual Care, Education, ACT).

Outcomes

The primary outcome was feasibility. Secondary outcomes included process and clinical outcomes.

Results

In total, 46 of 110 eligible adults were enrolled. Education occurred in 18/18 and 14/15 participants in the Education and ACT groups, respectively. 30-day urine protein evaluation occurred in 15%, 28%, and 87% of the Usual Care, Education, and ACT groups, respectively (P < 0.001). Cumulative incidence of provider (primary care or nephrologist) and laboratory follow-up at 14 and 30 days was different across groups (14 days: Usual care 0%, Education 11%, ACT 73% [P < 0.01]; 30 days: 0%, 22%, and 73% [P < 0.01]). 30-day readmission rates were 23%, 44%, and 13% in the Usual Care, Education, and ACT groups, respectively (P = 0.13).

Limitations

Patients were not randomly assigned to treatment groups. The sample size limited the ability to detect some differences or perform multivariable analysis.

Conclusions

This study demonstrated the feasibility of multidisciplinary AKI survivor follow-up beginning in primary care. We observed a higher cumulative incidence of laboratory and provider follow-up in ACT participants.

Trial Registration

ClinicalTrials.gov (NCT04505891).

Plain-Language Summary

Abrupt loss of kidney function in hospitalized patients, acute kidney injury (AKI), increases the chances of long-term kidney disease and a worse health care experience for patients. One out of 3 people who experience AKI do not get the follow-up kidney care they need. We performed a pilot study to test whether a program that facilitates structured AKI follow-up in primary care called the AKI in Care Transitions (ACT) program was possible. ACT brings together the unique expertise of nurses, doctors, and pharmacists to look at the patient's kidney health plan from all angles. The study found that the ACT program was possible and led to more complete kidney care follow-up after discharge than the normal approach to care.

Epidemiology and outcomes of post-AKI proteinuria

Background

Acute kidney injury (AKI) has been associated with increased risks of new-onset and worsening proteinuria. However, epidemiologic data for post-AKI proteinuria was still lacking. This study aimed to determine the incidence, risk factors and clinical correlations of post-AKI proteinuria among hospitalized patients.

Methods

This study was conducted in a multicenter cohort including patients aged 18-100 years with hospital-acquired AKI (HA-AKI) hospitalized at 19 medical centers throughout China. The primary outcome was the incidence of post-AKI proteinuria. Secondary outcomes included AKI recovery and kidney disease progression. The results of both quantitative and qualitative urinary protein tests were used to define post-AKI proteinuria. Cox proportional hazard model with stepwise regression was used to determine the risk factors for post-AKI proteinuria.

Results

Of 6206 HA-AKI patients without proteinuria at baseline, 2102 (33.9%) had new-onset proteinuria, whereas of 5137 HA-AKI with baseline proteinuria, 894 (17.4%) had worsening proteinuria after AKI. Higher AKI stage and preexisting CKD diagnosis were risk factors for new-onset proteinuria and worsening proteinuria, whereas treatment with renin-angiotensin system inhibitors was associated with an 11% lower risk of incident proteinuria. About 60% and 75% of patients with post-AKI new-onset and worsening proteinuria, respectively, recovered within 3 months. Worsening proteinuria was associated with a lower incidence of AKI recovery and a higher risk of kidney disease progression.

Conclusions

Post-AKI proteinuria is common and usually transient among hospitalized patients. The risk profiles for new-onset and worsening post-AKI proteinuria differed markedly. Worsening proteinuria after AKI was associated with adverse kidney outcomes, which emphasized the need for close monitoring of proteinuria after AKI.

Expectation of clinical decision support systems: a survey study among nephrologist end-users

BACKGROUND

Chronic kidney disease (CKD), a major public health problem with differing disease etiologies, leads to complications, comorbidities, polypharmacy, and mortality. Monitoring disease progression and personalized treatment efforts are crucial for long-term patient outcomes. Physicians need to integrate different data levels, e.g., clinical parameters, biomarkers, and drug information, with medical knowledge. Clinical decision support systems (CDSS) can tackle these issues and improve patient management. Knowledge about the awareness and implementation of CDSS in Germany within the field of nephrology is scarce.

PURPOSE

Nephrologists' attitude towards any CDSS and potential CDSS features of interest, like adverse event prediction algorithms, is important for a successful implementation. This survey investigates nephrologists' experiences with and expectations towards a useful CDSS for daily medical routine in the outpatient setting.

METHODS

The 38-item questionnaire survey was conducted either by telephone or as a do-it-yourself online interview amongst nephrologists across all of Germany. Answers were collected and analysed using the Electronic Data Capture System REDCap, as well as Stata SE 15.1, and Excel. The survey consisted of four modules: experiences with CDSS (M1), expectations towards a helpful CDSS (M2), evaluation of adverse event prediction algorithms (M3), and ethical aspects of CDSS (M4). Descriptive statistical analyses of all questions were conducted.

RESULTS

The study population comprised 54 physicians, with a response rate of about 80-100% per question. Most participants were aged between 51-60 years (45.1%), 64% were male, and most participants had been working in nephrology out-patient clinics for a median of 10.5 years. Overall, CDSS use was poor (81.2%), often due to lack of knowledge about existing CDSS. Most participants (79%) believed CDSS to be helpful in the management of CKD patients with a high willingness to try out a CDSS. Of all adverse event prediction algorithms, prediction of CKD progression (97.8%) and in-silico simulations of disease progression when changing, e. g., lifestyle or medication (97.7%) were rated most important. The spectrum of answers on ethical aspects of CDSS was diverse.

CONCLUSION

This survey provides insights into experience with and expectations of out-patient nephrologists on CDSS. Despite the current lack of knowledge on CDSS, the willingness to integrate CDSS into daily patient care, and the need for adverse event prediction algorithms was high.

Renin-Angiotensin-Aldosterone System Blockade after AKI with or without Recovery among US Veterans with Diabetic Kidney Disease

SIGNIFICANCE STATEMENT

Among patients with CKD, optimal use of angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers after AKI is uncertain. Despite these medications' ability to reduce risk of mortality and other adverse outcomes, there is concern that ACEi/ARB use may delay recovery of kidney function or precipitate recurrent AKI. Prior studies have provided conflicting data regarding the optimal timing of these medications after AKI and have not addressed the role of kidney recovery in determining appropriate timing. This study in US Veterans with diabetes mellitus and proteinuria demonstrated an association between ACEi/ARB use and lower mortality. This association was more pronounced with earlier post-AKI ACEi/ARB use and was not meaningfully affected by initiating ACEis/ARBs before versus after recovery from AKI.

BACKGROUND

Optimal use of angiotensin-converting enzyme inhibitors (ACEis) or angiotensin II receptor blockers (ARBs) after AKI is uncertain.

METHODS

Using data derived from electronic medical records, we sought to estimate the association between ACEi/ARB use after AKI and mortality in US military Veterans with indications for such treatment (diabetes and proteinuria) while accounting for AKI recovery. We used ACEi/ARB treatment after hospitalization with AKI (defined as serum creatinine ≥50% above baseline concentration) as a time-varying exposure in Cox models. The outcome was all-cause mortality. Recovery was defined as return to ≤110% of baseline creatinine. A secondary analysis focused on ACEi/ARB use relative to AKI recovery (before versus after).

RESULTS

Among 54,735 Veterans with AKI, 31,146 deaths occurred over a median follow-up period of 2.3 years. Approximately 57% received an ACEi/ARB <3 months after hospitalization. In multivariate analysis with time-varying recovery, post-AKI ACEi/ARB use was associated with lower risk of mortality (adjusted hazard ratio [aHR], 0.74; 95% confidence interval [CI], 0.72 to 0.77). The association between ACEi/ARB use and mortality varied over time, with lower mortality risk associated with earlier initiation ( P for interaction with time <0.001). In secondary analysis, compared with those with neither recovery nor ACEi/ARB use, risk of mortality was lower in those with recovery without ACEi/ARB use (aHR, 0.90; 95% CI, 0.87 to 0.94), those without recovery with ACEi/ARB use (aHR, 0.69; 95% CI, 0.66 to 0.72), and those with ACEi/ARB use after recovery (aHR, 0.70; 95% CI, 0.67 to 0.73).

CONCLUSIONS

This study demonstrated lower mortality associated with ACEi/ARB use in Veterans with diabetes, proteinuria, and AKI, regardless of recovery. Results favored earlier ACEi/ARB initiation.

Risk for Chronic Kidney Disease Progression After Acute Kidney Injury: Findings From the Chronic Renal Insufficiency Cohort Study

BACKGROUND

Prior studies associating acute kidney injury (AKI) with more rapid subsequent loss of kidney function had methodological limitations, including inadequate control for differences between patients who had AKI and those who did not.

OBJECTIVE

To determine whether AKI is independently associated with subsequent kidney function trajectory among patients with chronic kidney disease (CKD).

DESIGN

Multicenter prospective cohort study.

SETTING

United States.

PARTICIPANTS

Patients with CKD (n = 3150).

MEASUREMENTS

Hospitalized AKI was defined by a 50% or greater increase in inpatient serum creatinine (SCr) level from nadir to peak. Kidney function trajectory was assessed using estimated glomerular filtration rate (eGFR) based on SCr level (eGFRcr) or cystatin C level (eGFRcys) measured at annual study visits.

RESULTS

During a median follow-up of 3.9 years, 433 participants had at least 1 AKI episode. Most episodes (92%) had stage 1 or 2 severity. There were decreases in eGFRcr (-2.30 [95% CI, -3.70 to -0.86] mL/min/1.73 m2) and eGFRcys (-3.61 [CI, -6.39 to -0.82] mL/min/1.73 m2) after AKI. However, in fully adjusted models, the decreases were attenuated to -0.38 (CI, -1.35 to 0.59) mL/min/1.73 m2 for eGFRcr and -0.15 (CI, -2.16 to 1.86) mL/min/1.73 m2 for eGFRcys, and the CI bounds included the possibility of no effect. Estimates of changes in eGFR slope after AKI determined by either SCr level (0.04 [CI, -0.30 to 0.38] mL/min/1.73 m2 per year) or cystatin C level (-0.56 [CI, -1.28 to 0.17] mL/min/1.73 m2 per year) also had CI bounds that included the possibility of no effect.

LIMITATIONS

Few cases of severe AKI, no adjudication of AKI cause, and lack of information about nephrotoxic exposures after hospital discharge.

CONCLUSION

After pre-AKI eGFR, proteinuria, and other covariables were accounted for, the association between mild to moderate AKI and worsening subsequent kidney function in patients with CKD was small.

PRIMARY FUNDING SOURCE

National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health.

Risk of de novo proteinuria following hospitalization with acute kidney injury

BACKGROUND

Acute Kidney Injury (AKI) incidence has continued to rise and is recognized as a major risk factor for kidney disease progression and cardiovascular complications. Early recognition of factors associated with post-AKI complications is fundamental to stratifying patients that could benefit from closer follow-up and management after an episode of AKI. Recent studies have shown that proteinuria is a prevalent sequela after AKI and a strong predictor of complications post-AKI. This study aims to evaluate the frequency and timing of the development of de-novo proteinuria after an AKI episode in patients with known kidney function and no prior history of proteinuria.

METHODS

We retrospectively analyzed data from adult AKI patients with pre- and post-kidney function information between Jan 2014 and March 2019. The presence of proteinuria determined before and after index AKI encounter was based on ICD-10 code and/or urine dipstick and UPCR during the follow-up period.

RESULTS

Of 9697 admissions with AKI diagnoses between Jan 2014 and March 2019, 2120 eligible patients with at least one assessment of Scr and proteinuria before AKI index admission were included in the analysis. The median age was 64 (IQR 54-75) years, and 57% were male. 58% (n-1712) patients had stage 1 AKI, 19% (n = 567) stage 2 AKI, and 22% (n = 650) developed stage 3 AKI. De novo proteinúria was found in 62% (n = 472) of patients and was already present by 90 days post-AKI in 59% (209/354). After adjusting for age and comorbidities, severe AKI (stage 2/3 AKI) and diabetes, were independently associated with increased risk for De novo proteinuria.

CONCLUSION

Severe AKI is an independent risk factor for subsequent de novo proteinuria post-hospitalization. Further prospective studies are needed to determine whether strategies to detect AKI patients at risk of proteinuria and early therapeutics to modify proteinuria can delay the progression of kidney disease.

Black and White Adults With CKD Hospitalized With Acute Kidney Injury: Findings From the Chronic Renal Insufficiency Cohort (CRIC) Study

RATIONALE & OBJECTIVE

Few studies have investigated racial disparities in acute kidney injury (AKI), in contrast to the extensive literature on racial differences in the risk of kidney failure. We sought to study potential differences in risk in the setting of chronic kidney disease (CKD).

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

We studied 2,720 self-identified Black or White participants with CKD enrolled in the Chronic Renal Insufficiency Cohort (CRIC) Study from July 1, 2013, to December 31, 2017.

EXPOSURE

Self-reported race (Black vs White).

OUTCOME

Hospitalized AKI (≥50% increase from nadir to peak serum creatinine).

ANALYTICAL APPROACH

Cox regression models adjusting for demographics (age and sex), prehospitalization clinical risk factors (diabetes, blood pressure, cardiovascular disease, estimated glomerular filtration rate, proteinuria, receipt of angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers), and socioeconomic status (insurance status and education level). In a subset of participants with genotype data, we adjusted for apolipoprotein L1 gene (APOL1) high-risk status and sickle cell trait.

RESULTS

Black participants (n = 1,266) were younger but had a higher burden of prehospitalization clinical risk factors. The incidence rate of first AKI hospitalization among Black participants was 6.3 (95% CI, 5.5-7.2) per 100 person-years versus 5.3 (95% CI, 4.6-6.1) per 100 person-years among White participants. In an unadjusted Cox regression model, Black participants were at a modestly increased risk of incident AKI (HR, 1.22 [95% CI, 1.01-1.48]) compared with White participants. However, this risk was attenuated and no longer significant after adjusting for prehospitalization clinical risk factors (adjusted HR, 1.02 [95% CI, 0.83-1.25]). There were only 11 AKI hospitalizations among individuals with high-risk APOL1 risk status and 14 AKI hospitalizations among individuals with sickle cell trait.

LIMITATIONS

Participants were limited to research volunteers and potentially not fully representative of all CKD patients.

CONCLUSIONS

In this multicenter prospective cohort of CKD patients, racial disparities in AKI incidence were modest and were explained by differences in prehospitalization clinical risk factors.

Absence of long-term changes in urine biomarkers after AKI: findings from the CRIC study

BACKGROUND

Mechanisms by which AKI leads to CKD progression remain unclear. Several urine biomarkers have been identified as independent predictors of progressive CKD. It is unknown whether AKI may result in long-term changes in these urine biomarkers, which may mediate the effect of AKI on CKD progression.

METHODS

We selected 198 episodes of hospitalized AKI (defined as peak/nadir inpatient serum creatinine values ≥ 1.5) among adult participants in the Chronic Renal Insufficiency Cohort (CRIC) Study. We matched the best non-AKI hospitalization (unique patients) for each AKI hospitalization using pre-hospitalization characteristics including eGFR and urine protein/creatinine ratio. Biomarkers were measured in banked urine samples collected at annual CRIC study visits.

RESULTS

Urine biomarker measurements occurred a median of 7 months before and 5 months after hospitalization. There were no significant differences in the change in urine biomarker-to-creatinine ratio between the AKI and non-AKI groups: KIM-1/Cr + 9% vs + 7%, MCP-1/Cr + 4% vs + 1%, YKL-40/Cr + 7% vs -20%, EGF/Cr -11% vs -8%, UMOD/Cr -2% vs -7% and albumin/Cr + 17% vs + 13% (all p > 0.05).

CONCLUSION

In this cohort of adults with CKD, AKI did not associate with long-term changes in urine biomarkers.

Survival and kidney recovery among recipients of continuous renal replacement therapy

Continuous renal replacement therapy (CRRT) is widely used in the care of critically ill patients with acute kidney injury (AKI). Despite hopeful trends suggested by recent studies, mortality among CRRT recipients with severe AKI remains extremely high. Moreover, CRRT does not confer a reduction in mortality in trials comparing CRRT to intermittent RRT modalities. Among AKI survivors, some preliminary studies suggest a higher likelihood of kidney recovery and dialysis independence in CRRT recipients. AKI survivors are at risk for a broad array of adverse outcomes; strategies that may mitigate these risks are discussed.

Retrospective Study on Acute Kidney Injury among Cholera Patients in an Outbreak in Whitefield, Bengaluru

Introduction

Cholera is gastroenteritis caused by Vibrio cholerae. It presents with vomiting, severe secretory diarrhoea, and dehydration. It can cause severe complications with severe electrolyte imbalances and oligoanuric acute kidney injury due to acute tubular necrosis secondary to dehydration or infection itself. However, cholera presenting with significant proteinuria and acute kidney injury has not been reported. Hence, this study was conducted. Aims and Objectives. This aim of this study was to assess clinical features, treatment, and prognosis of AKI in cholera patients; to correlate proteinuria with AKI in cholera patients; and to compare cholera patients with normal kidney function and those with AKI. Material and Methods. It was a retrospective observational study involving patients with cholera. Information regarding cholera patients with acute kidney injury, proteinuria, and prognosis were collected.

Results

Most of the patients had significant vomiting, moderate-to-severe diarrhoea, dehydration, and hypovolaemic shock. Cholera caused severe complications such as severe electrolyte imbalances including hyponatraemia and hypokalaemia, acute kidney injury, and proteinuria secondary to dehydration or infection. A surprising finding noted was the lack of significant association between the onset of acute kidney injury and usual risk factors such as hypovolaemic shock and dehydration. It was found that proteinuria had influenced the onset of acute kidney injury, but it did not influence recovery. As there was complete recovery in kidney function, none of the cases required kidney biopsy. There was no mortality noted.

Conclusions

This study points towards the rare occurrence of proteinuria and acute kidney injury in Vibrio cholerae infection with spontaneous remission of kidney disease with appropriate therapy.

Vegfa promoter gene hypermethylation at HIF1α binding site is an early contributor to CKD progression after renal ischemia

Chronic hypoxia is a major contributor to Chronic Kidney Disease (CKD) after Acute Kidney Injury (AKI). However, the temporal relation between the acute insult and maladaptive renal response to hypoxia remains unclear. In this study, we analyzed the time-course of renal hemodynamics, oxidative stress, inflammation, and fibrosis, as well as epigenetic modifications, with focus on HIF1α/VEGF signaling, in the AKI to CKD transition. Sham-operated, right nephrectomy (UNx), and UNx plus renal ischemia (IR + UNx) groups of rats were included and studied at 1, 2, 3, or 4 months. The IR + UNx group developed CKD characterized by progressive proteinuria, renal dysfunction, tubular proliferation, and fibrosis. At first month post-ischemia, there was a twofold significant increase in oxidative stress and reduction in global DNA methylation that was maintained throughout the study. Hif1α and Vegfa expression were depressed in the first and second-months post-ischemia, and then Hif1α but not Vegfa expression was recovered. Interestingly, hypermethylation of the Vegfa promoter gene at the HIF1α binding site was found, since early stages of the CKD progression. Our findings suggest that renal hypoperfusion, inefficient hypoxic response, increased oxidative stress, DNA hypomethylation, and, Vegfa promoter gene hypermethylation at HIF1α binding site, are early determinants of AKI-to-CKD transition.

Risk Factors for CKD Progression: Overview of Findings from the CRIC Study

The Chronic Renal Insufficiency Cohort (CRIC) Study is an ongoing, multicenter, longitudinal study of nearly 5500 adults with CKD in the United States. Over the past 10 years, the CRIC Study has made significant contributions to the understanding of factors associated with CKD progression. This review summarizes findings from longitudinal studies evaluating risk factors associated with CKD progression in the CRIC Study, grouped into the following six thematic categories: (1) sociodemographic and economic (sex, race/ethnicity, and nephrology care); (2) behavioral (healthy lifestyle, diet, and sleep); (3) genetic (apoL1, genome-wide association study, and renin-angiotensin-aldosterone system pathway genes); (4) cardiovascular (atrial fibrillation, hypertension, and vascular stiffness); (5) metabolic (fibroblast growth factor 23 and urinary oxalate); and (6) novel factors (AKI and biomarkers of kidney injury). Additionally, we highlight areas where future research is needed, and opportunities for interdisciplinary collaboration.

Individualized acute kidney injury after care

PURPOSE OF REVIEW

The aim of this study was to summarize the current evidence around the impact of individualizing patient care following an episode of acute kidney injury (AKI) in the ICU.

RECENT FINDINGS

Over the last years, evidence has demonstrated that the follow-up care after episodes of AKI is lacking and standardization of this process is likely needed. Although this is informed largely by large retrospective cohort studies, a few prospective observational trials have been performed. Medication reconciliation and patient/caregiver education are important tenants of follow-up care, regardless of the severity of AKI. There is evidence the initiation and/or reinstitution of renin-angiotensin-aldosterone agents may improve patient's outcomes following AKI, although they may increase the risk for adverse events, especially when reinitiated early. In addition, 3 months after an episode of AKI, serum creatinine and proteinuria evaluation may help identify patients who are likely to develop progressive chronic kidney disease over the ensuing 5 years. Lastly, there are emerging differences between those who do and do not require renal replacement therapy (RRT) for their AKI, which may require more frequent and intense follow-up in those needing RRT.

SUMMARY

Although large scale evidence-based guidelines are lacking, standardization of post-ICU-AKI is needed.

Prospective Cohort Study of Renin-Angiotensin System Blocker Usage after Hospitalized Acute Kidney Injury

BACKGROUND AND OBJECTIVES

The risk-benefit ratio of angiotensin-converting enzyme inhibitor or angiotensin receptor blocker therapy after AKI may be altered due to concerns regarding recurrent AKI. We evaluated, in a prospective cohort, the association between use (versus nonuse) of angiotensin-converting enzyme inhibitors/angiotensin receptor blockers and the subsequent risk of AKI and other adverse outcomes after hospitalizations with and without AKI.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We studied 1538 patients recently discharged from the hospital who enrolled in the multicenter, prospective ASSESS-AKI study, with approximately half of patients experiencing AKI during the index hospitalization. All participants were seen at a baseline visit 3 months after their index hospitalization and were categorized at that time on whether they were using angiotensin-converting enzyme inhibitors/angiotensin receptor blockers or not. We used multivariable Cox regression, adjusting for demographics, comorbidities, eGFR, urine protein-creatinine ratio, and use of other medications, to examine the association between angiotensin-converting enzyme inhibitor/angiotensin receptor blocker use and subsequent risks of AKI, death, kidney disease progression, and adjudicated heart-failure events.

RESULTS

The use of angiotensin-converting enzyme inhibitors/angiotensin receptor blockers was 50% (386/769) among those with AKI during the index hospitalization and 47% (362/769) among those without. Among those with AKI during the index hospitalization, angiotensin-converting enzyme inhibitor/angiotensin receptor blocker use was not associated with a higher risk of recurrent hospitalized AKI (adjusted hazard ratio, 0.88; 95% confidence interval, 0.69 to 1.13). Associations between angiotensin-converting enzyme inhibitor/angiotensin receptor blocker use and death, kidney disease progression, and adjudicated heart-failure events appeared similar in study participants who did and did not experience AKI during the index hospitalization (all interaction P values >0.05).

CONCLUSIONS

The risk-benefit ratio of angiotensin-converting enzyme inhibitor/angiotensin receptor blocker therapy after hospital discharge appears to be similar regardless of whether AKI occurred during the hospitalization.

Care of the Survivor of Critical Illness and Acute Kidney Injury: A Multidisciplinary Approach

Acute kidney injury (AKI) is a common complication of critical illness and is associated with adverse short- and long-term health consequences. Survivors of critical illness and AKI experience poor kidney, cardiovascular and quality of life outcomes, along with increased mortality. Yet, many patients surviving AKI are unaware that there is a problem with their kidney health, and post-AKI nephrology follow-up occurs at very low rates. Although there is a paucity of evidence-based studies to guide post-AKI care, attention to risk factors such as hypertension and albuminuria are requisite. There are several ongoing or planned studies which are expected to help inform specific management in the future. Until then, a multidisciplinary approach is warranted to address areas such as quality of life, physical rehabilitation, dietary modifications, and medication reconciliation.

Association of Proteinuria and Hematuria with Acute Kidney Injury and Mortality in Hospitalized Patients with COVID-19

INTRODUCTION

Acute kidney injury (AKI) is strongly associated with poor outcomes in hospitalized patients with coronavirus disease 2019 (COVID-19), but data on the association of proteinuria and hematuria are limited to non-US populations. In addition, admission and in-hospital measures for kidney abnormalities have not been studied separately.

METHODS

This retrospective cohort study aimed to analyze these associations in 321 patients sequentially admitted between March 7, 2020 and April 1, 2020 at Stony Brook University Medical Center, New York. We investigated the association of proteinuria, hematuria, and AKI with outcomes of inflammation, intensive care unit (ICU) admission, invasive mechanical ventilation (IMV), and in-hospital death. We used ANOVA, t test, χ2 test, and Fisher's exact test for bivariate analyses and logistic regression for multivariable analysis.

RESULTS

Three hundred patients met the inclusion criteria for the study cohort. Multivariable analysis demonstrated that admission proteinuria was significantly associated with risk of in-hospital AKI (OR 4.71, 95% CI 1.28-17.38), while admission hematuria was associated with ICU admission (OR 4.56, 95% CI 1.12-18.64), IMV (OR 8.79, 95% CI 2.08-37.00), and death (OR 18.03, 95% CI 2.84-114.57). During hospitalization, de novo proteinuria was significantly associated with increased risk of death (OR 8.94, 95% CI 1.19-114.4, p = 0.04). In-hospital AKI increased (OR 27.14, 95% CI 4.44-240.17) while recovery from in-hospital AKI decreased the risk of death (OR 0.001, 95% CI 0.001-0.06).

CONCLUSION

Proteinuria and hematuria both at the time of admission and during hospitalization are associated with adverse clinical outcomes in hospitalized patients with COVID-19.

Acute Kidney Injury: A Bona Fide Complication of Diabetes

The landscape of kidney disease in diabetes has shifted. The classical dogma of "diabetic nephropathy" progressing through stages of albuminuria, leading to decline in glomerular filtration rate and end-stage kidney disease (ESKD), has been replaced by a more nuanced understanding of the complex and heterogeneous nature of kidney disease in diabetes. Paralleling this evolution, standardized definitions have resulted in a growing appreciation that acute kidney injury (AKI) is increasing in its incidence rapidly and that people with diabetes are much more likely to develop AKI than people without diabetes. Here, I propose that AKI should be considered a complication of diabetes alongside other complications that similarly do not fit neatly into the historical microvascular/macrovascular paradigm. In this article, we take a look at the evidence indicating that diabetes is a major risk factor for AKI and we review the causes of this increased risk. We consider the long-term implications of AKI in diabetes and its potential contribution to the future development of chronic kidney disease, ESKD, and mortality. Finally, we look toward the future at strategies to better identify people at risk for AKI and to develop new approaches to improve AKI outcomes. Recognizing AKI as a bona fide complication of diabetes should open up new avenues for investigation that may ultimately improve the outlook for people living with diabetes and at risk for kidney disease.

Renin-angiotensin aldosterone inhibitor use at hospital discharge among patients with moderate to severe acute kidney injury and its association with recurrent acute kidney injury and mortality

Recurrent episodes of acute kidney injury (AKI) are common among AKI survivors. Renin-angiotensin aldosterone inhibitors (RAASi) are often indicated for these patients but may increase the risk for recurrent AKI. Here, we examined whether RAASi associates with a higher risk for recurrent AKI and mortality among survivors of moderate to severe AKI in a retrospective cohort of Veterans who survived Stage II or III AKI. The primary exposure was RAASi at hospital discharge and the primary endpoint was recurrent AKI within 12 months. Cox proportional hazards models were fit on a propensity score-weighted cohort to compare time to recurrent AKI and mortality by RAASi exposure. Among 96,983 patients, 40% were on RAASi at discharge. Compared to patients who continued RAASi use, those discontinuing use experienced no difference in risk for recurrent AKI but had a significantly higher risk of mortality [hazard ratio 1.33 (95% confidence interval1.26-1.41)]. No differences in recurrent AKI risk was observed for non-users started or not on RAASi compared to prevalent users who continued RAASi. Subgroup analyses among those with diabetes, chronic kidney disease, heart failure, and malignancy were similar with exception of a modest reduction in recurrent AKI risk among RAASi discontinuers with chronic kidney disease. Thus, RAASi use among survivors of moderate to severe AKI was associated with little to no difference in risk for recurrent AKI but was associated with improved survival. Reinitiating or starting RAASi among patients with strong indications is warranted but should be balanced with individual overall risk for recurrent AKI and with adequate monitoring.

Decision Algorithm for Prescribing SGLT2 Inhibitors and GLP-1 Receptor Agonists for Diabetic Kidney Disease

Diabetic kidney disease and its comorbid conditions, including atherosclerotic cardiovascular disease, heart failure, diabetes, and obesity, are interconnected conditions that compound the risk of kidney failure and cardiovascular mortality, and exponentiate health care costs. Sodium glucose cotransporter 2 inhibitor (SGLT2i) and glucagon-like peptide 1 receptor agonist (GLP-1 RA) are novel diabetes medications that prevent cardiovascular events and kidney failure. Clinical trials exploring the cardiovascular and kidney outcomes of SGLT2i and GLP-1 RA have fundamentally shifted the treatment paradigm of diabetes. Clinical guidelines for diabetes management recommend a more holistic approach beyond glycemic control and emphasize heart and kidney protection of SGLT2i and GLP-1 RA. However, the adoption of prescribing SGLT2i and GLP-1 RA for patients with diabetes and high cardiovascular and kidney risk has been slow. In this review, we provide a decision-making tool to help clinicians determine when to consider SGLT2i and GLP-1 RA for heart and kidney protection. First, we discuss a comprehensive risk assessment for patients with diabetic kidney disease. We compare the effectiveness of SGLT2i and GLP-1 RA for different risk categories. Then, we present a decision algorithm using cardiovascular and kidney failure risk stratification and the strength of current evidence for the use of SGLT2i and GLP-1 RA. Lastly, we review the adverse effects of SGLT2i and GLP-1 RA and propose mitigation strategies.

Long-term complications of acute kidney injury in children

PURPOSE OF REVIEW

The current review will describe the current evidence and mechanisms of acute kidney injury (AKI) as a risk factor for long-term kidney complications, summarize the rationale for AKI follow-up and present an approach to monitoring children with AKI. Despite emerging evidence linking AKI with risk for long-term kidney and cardiovascular outcomes, many children who develop AKI are not followed for kidney disease development after hospital discharge. Better understanding of long-term complications after AKI and practical algorithms for follow-up will hopefully increase the rate and quality of post-AKI monitoring.

RECENT FINDINGS

Recent evidence shows that pediatric AKI is associated with long-term renal outcomes such as chronic kidney disease (CKD) and hypertension, both known to increase cardiovascular risk. The mechanism of AKI progression to CKD involves maladaptive regeneration of tubular epithelial and endothelial cells, inflammation, fibrosis and glomerulosclerosis. Many AKI survivors are not followed, and no guidelines for pediatric AKI follow-up have been published.

SUMMARY

Children who had AKI are at increased risk of long-term renal complications but many of them are not monitored for these complications. Recognizing long-term outcomes post-AKI and integration of follow-up programs may have a long-lasting positive impact on patient health.

Long-term outcomes of acute kidney injury and strategies for improved care

Acute kidney injury (AKI), once viewed predominantly as a self-limited and reversible condition, is now recognized as a growing problem associated with significant risks of adverse long-term health outcomes. Many cohort studies have established important relationships between AKI and subsequent risks of recurrent AKI, hospital re-admission, morbidity and mortality from cardiovascular disease and cancer, as well as the development of chronic kidney disease and end-stage kidney disease. In both high-income countries (HICs) and low-income or middle-income countries (LMICs), several challenges exist in providing high-quality, patient-centered care following AKI. Despite advances in our understanding about the long-term risks following AKI, large gaps in knowledge remain about effective interventions that can improve the outcomes of patients. Therapies for high blood pressure, glycaemic control (for patients with diabetes), renin-angiotensin inhibition and statins might be important in improving long-term cardiovascular and kidney outcomes after AKI. Novel strategies that incorporate risk stratification approaches, educational interventions and new models of ambulatory care following AKI have been described, and some of these are now being implemented and evaluated in clinical studies in HICs. Care for AKI in LMICs must overcome additional barriers due to limited resources for diagnosis and management.

Post-Acute Kidney Injury Proteinuria and Subsequent Kidney Disease Progression: The Assessment, Serial Evaluation, and Subsequent Sequelae in Acute Kidney Injury (ASSESS-AKI) Study

IMPORTANCE

Among patients who had acute kidney injury (AKI) during hospitalization, there is a need to improve risk prediction such that those at highest risk for subsequent loss of kidney function are identified for appropriate follow-up.

OBJECTIVE

To evaluate the association of post-AKI proteinuria with increased risk of future loss of renal function.

DESIGN, SETTING, AND PARTICIPANTS

The Assessment, Serial Evaluation, and Subsequent Sequelae in Acute Kidney Injury (ASSESS-AKI) Study was a multicenter prospective cohort study including 4 clinical centers in North America included 1538 patients enrolled 3 months after hospital discharge between December 2009 and February 2015.

EXPOSURES

Urine albumin-to-creatinine ratio (ACR) quantified 3 months after hospital discharge.

MAIN OUTCOMES AND MEASURES

Kidney disease progression defined as halving of estimated glomerular filtration rate (eGFR) or end-stage renal disease.

RESULTS

Of the 1538 participants, 769 (50%) had AKI durring hospitalization. The baseline study visit took place at a mean (SD) 91 (23) days after discharge. The mean (SD) age was 65 (13) years; the median eGFR was 68 mL/min/1.73 m2; and the median urine ACR was 15 mg/g. Overall, 547 (37%) study participants were women and 195 (13%) were black. After a median follow-up of 4.7 years, 138 (9%) participants had kidney disease progression. Higher post-AKI urine ACR level was associated with increased risk of kidney disease progression (hazard ratio [HR], 1.53 for each doubling; 95% CI, 1.45-1.62), and urine ACR measurement was a strong discriminator for future kidney disease progression (C statistic, 0.82). The performance of urine ACR was stronger in patients who had had AKI than in those who had not (C statistic, 0.70). A comprehensive model of clinical risk factors (eGFR, blood pressure, and demographics) including ACR provided better discrimination for predicting kidney disease progression after hospital discharge among those who had had AKI (C statistic, 0.85) vs those who had not (C statistic, 0.76). In the entire matched cohort, after taking into account urine ACR, eGFR, demographics, and traditional chronic kidney risk factors determined 3 months after discharge, AKI (HR, 1.46; 95% CI, 0.51-4.13 for AKI vs non-AKI) or severity of AKI (HR, 1.54; 95% CI, 0.50-4.72 for AKI stage 1 vs non-AKI; HR, 0.56; 95% CI, 0.07-4.84 for AKI stage 2 vs non-AKI; HR, 2.24; 95% CI, 0.33-15.29 for AKI stage 3 vs non-AKI) was not independently associated with more rapid kidney disease progression.

CONCLUSIONS AND RELEVANCE

Proteinuria level is a valuable risk-stratification tool in the post-AKI period. These results suggest there should be more widespread and routine quantification of proteinuria after hospitalized AKI.

Long-Term Outcomes in Patients with Acute Kidney Injury

The long-term sequelae of AKI have received increasing attention so that its associations with a number of adverse outcomes, including higher mortality and development of CKD, are now widely appreciated. These associations take on particular importance when considering the high incidence of AKI, with a lack of proven interventions and uncertainties around optimal care provision meaning that the long-term sequelae of AKI present a major unmet clinical need. In this review, we examine the published data that inform our current understanding of long-term outcomes following AKI and discuss potential knowledge gaps, covering long-term mortality, CKD, progression to ESKD, proteinuria, cardiovascular events, recurrent AKI, and hospital readmission.