Chronic kidney disease: an inherent risk factor for acute kidney injury?

Deletion of Pyruvate Carboxylase in Tubular Epithelial Cell Promotes Renal Fibrosis by Regulating SQOR/cGAS/STING-Mediated Glycolysis

Renal fibrosis is a common pathway involved in the progression of various chronic kidney diseases to end-stage renal disease. Recent studies show that mitochondrial injury of renal tubular epithelial cells (RTECs) is a crucial pathological foundation for renal fibrosis. However, the underlying regulatory mechanisms remain unclear. Pyruvate carboxylase (PC) is a catalytic enzyme located within the mitochondria that is intricately linked with mitochondrial damage and metabolism. In the present study, the downregulation of PC in various fibrotic animal and human kidney samples is demonstrated. Renal proximal tubule-specific Pcx gene knockout mice (PcxcKO) has significant interstitial fibrosis compared to control mice, with heightened expression of extracellular matrix molecules. This is further demonstrated in a stable PC knock-out RTEC line. Mechanistically, PC deficiency reduces its interaction with sulfide:quinone oxidoreductase (SQOR), increasing the ubiquitination and degradation of SQOR. This leads to mitochondrial morphological and functional disruption, increased mtDNA release, activation of the cGAS-STING pathway, and elevated glycolysis levels, and ultimately, promotes renal fibrosis. This study investigates the molecular mechanisms through which PC deficiency induces mitochondrial injury and metabolic reprogramming in RTECs. This study provides a novel theoretical foundation and potential therapeutic targets for the pathogenesis and treatment of renal fibrosis.

Acute kidney injury in patients treated with immune checkpoint inhibitors: a single-center retrospective study

BACKGROUND

Immune checkpoint inhibitor-associated acute kidney injury (ICI-AKI) is the most common renal complication and has attracted increasing amounts of attention. However, studies on this topic in Chinese cancer patients are very limited. Therefore, we conducted a retrospective study on the incidence, risk factors, clinical features and renal recovery of ICI-AKI in all patients with malignancies treated with ICIs in Shandong Provincial Hospital Affiliated to Shandong First Medical University.

METHODS

In this single-center retrospective cohort study, the data of 904 patients who received immune checkpoint inhibitors (ICIs) treatment were retrospectively analyzed. Multivariable logistic regression was used to identify the predictors of ICI-AKI.

RESULTS

A total of 46 of 904 patients receiving ICIs developed ICI-AKI, and the incidence of ICI-AKI was 5.1%. Patients developed ICI-AKI at a median of 9 weeks (IQR 3-23) after ICIs initiation. A lower baseline estimated glomerular filtration rate (eGFR) and use of antibiotics were associated with a higher risk of ICI-AKI. Renal recovery occurred in 17 patients (46%) at a median of 4 weeks (IQR 2-8) after ICI-AKI, including 16 (43%) with complete recovery and 1 (3%) with partial recovery. Of the 14 rechallenged patients, only one developed recurrent ICI-AKI.

CONCLUSIONS

Patients with ICI-AKI were more likely to have impaired renal function at baseline and after treatment with antibiotics. Approximately half of the patients achieved renal recovery.

A Retrospective Analysis of Mortality Due to Pneumonia and Renal Disease in a Midwestern Patient Population

BACKGROUND

The impact of pneumonia (PNA) with concomitant renal disease (RD) has not been fully investigated in a United States Midwestern patient population, despite the morbidity and mortality associated with such diseases.

MATERIALS AND METHODS

A retrospective cohort study was performed on International Classification of Diseases, 10th Revision (ICD-10) data from a hospital system located in Southwest Missouri. Data was acquired from patients admitted between January 2019 and December 2021. Patients were separated into five groups (disease categories): acute kidney injury (AKI), chronic kidney disease (CKD), PNA, AKI with PNA, and CKD with PNA. The data were analyzed, and subset analysis was performed utilizing two-sample proportion tests (Wald test) to compare mortality rates. Informed consent was not needed due to the retrospective nature of the study.

RESULTS

 The mortality rate of patients with PNA with AKI and PNA with CKD was 36.08% (32.87% to 39.28%, 95% CI) and 24.97% (21.93% to 28.00%, 95% CI), respectively, revealing a significant increase in mortality for thosediagnosed with PNA and AKI -higher than any other disease category. For reference, PNA without (w/o) RD, CKD w/o PNA, and AKI w/o PNA had much lower mortality rates at 9.45%, 7.87% and 12.19%, respectively, with AKI w/o PNA having a 2.63% to 6.00% higher (p<0.0001) and 0.99% to 4.49% higher (p=0.0020), mortality alone than CKD w/o PNA or PNA w/o RD, respectively.

DISCUSSION AND CONCLUSION

Mortality associated with RD and PNA was examined in a predominantly rural, relatively poor, Midwestern patient population presenting to a tertiary center with the key finding that the presence of AKI correlates with a much greater mortality rate in both patients with and without PNA. Looking forward, future studies may include a broader population base(including urban, suburban, and rural areas), allowing not only for more statistical power but also a broader assessment of the population.Such knowledge is invaluable as we continue to prioritize healthcare resources for critically ill patients suffering from RD and PNA in different settings.

Evaluating the incidence and risk factors for developing acute tubular necrosis after percutaneous coronary intervention in the management of coronary artery dissection

BACKGROUND

Coronary artery dissection is managed primarily conservatively with serial imaging or percutaneous coronary intervention (PCI). Exposure to contrast in either modality could potentially result in acute tubular necrosis (ATN). However, no data compares ATN incidence in these management strategies. This study compares the incidence of ATN and associated mortality of PCI and conservative management of coronary artery dissection.

METHODS

A retrospective analysis was performed using data from the National Inpatient Sample database, including patients with coronary artery dissection between 2016 through 2020. We analyzed the incidence of ATN and associated mortality of PCI and conservative management of coronary artery dissection.

RESULTS

We found that the odds of developing ATN were 22% lower in patients managed with PCI than those managed conservatively. There was no difference in the in-hospital mortality or hospital length of stay between the two groups but the mortality rate in patients with ATN was double that of those who did not develop ATN in both PCI and conservatively managed groups.

CONCLUSIONS

The higher incidents of ATN in patients with coronary dissection being managed with conservative measures compared to PCI suggest that the use of CTA may be harmful. Additionally, persons who developed ATN may have higher mortality. Therefore, more studies in the management of coronary artery dissection need to be done which would allow further steps to be taken to reduce this harm.

Leveraging Electronic Health Records to Predict the Risk of Acute Kidney Injury after Allogeneic Hematopoietic Cell Transplantation

BACKGROUND

The objective of this study is to assess the electronic health records (EHRs), which are potential risk factors for acute kidney injury (AKI) after allogenic hematopoietic cell transplantation (allo-HCT), and to propose a basic dataset and score for the calculation of HCT-acute kidney injury risk (HCT-AKIR).

METHODS

We undertook a retrospective analysis of the EHRs of 312 patients. Pre- and post-transplant factors were assessed, recognizing the following structured entries: laboratory data, encounters, medication, imaging studies, diagnoses, and procedures. Composite variables were used to create patient groups by combining two or more multivariate significant risk factors for AKI. The EHRs dataset and HCT-AKIR score were created based on the multivariate analysis of the composite variables.

RESULTS

A multivariate analysis showed that previous CKD and once-impaired pre-transplant kidney function, sepsis, imaging procedures with contrast media, and cumulative length of intensive care unit stay after transplantation were significant risk factors. A new unit-weighted composite score based on the combination of significant risk factors contained in common EHR resources was proposed.

CONCLUSIONS

Using our novel HCT-AKIR score calculated from the basic EHR dataset could be an easy way to increase awareness of post-transplant AKI and provide risk stratification.

Impact of chronic kidney disease and end-stage renal disease on outcomes after complex endovascular and open aortic aneurysm repair

OBJECTIVE

Chronic kidney disease (CKD) and end-stage renal disease are traditionally associated with worse outcomes after endovascular aortic repair (EVAR) and open aneurysm repair (OAR) of abdominal aortic aneurysms (AAAs). However, there needs to be more data on complex AAA repair involving the aorta's visceral segment. This study stratifies complex AAA repair outcomes by CKD severity and dialysis dependence.

METHODS

All patients undergoing elective OAR and fenestrated/branched EVAR (F-BEVAR) for complex AAA with preoperative renal function data captured by the Vascular Quality Initiative between January 2003 and September 2020 were analyzed. Patients were stratified by CKD class as follows: normal/mild (CKD 1 and 2), moderate (CKD class 3a), moderate to severe (CKD 3b), severe (CKD class 4 and 5), and dialysis. Only patients with clamp sites above one of the renal arteries were included for complex OAR. For F-BEVAR, patients with proximal landing zones below zone 5 (above celiac artery) were included, and distal landing zones between zones 1 and 5 were excluded. Primary outcomes were perioperative and 1-year mortality. Predictors of mortality were identified by Cox multivariate regression models.

RESULTS

We identified 7849 elective complex AAA repairs: 4230 (54%) complex OARs and 3619 (46%) F-BEVARs. Most patients were White (89%) and male (74%), with an average age of 72 ± 8 years. The patients who underwent F-BEVAR were older and had more comorbidities. Elective F-BEVAR for complex AAA started in 2012 and increased from 1.4% in 2012 to 58% in 2020 (P < .001). The OAR cohort had more perioperative complications, but less 1-year mortality. The normal/mild CKD cohort had the highest 1-year survival compared with other groups after both complex OAR and F-BEVAR. On Cox regression analysis, when compared with CKD 1-2, worsening CKD stage (CKD 3b: hazard ratio [HR], 2.5; 95% confidence interval [CI], 1.82-3.40; P < .001; CKD 4-5: HR, 1.9; 95% CI, 1.16-3.26; P = .011; and dialysis: HR, 4.4; 95% CI, 2.53-7.72; P < .001) were independently associated with 1-year survival after F-BEVAR. After complex OAR, worsening CKD stage but not dialysis was associated with 1-year mortality compared with CKD 1-2 (CKD 3b: HR, 1.6; 95% CI, 1.13-2.35; P = .009; CKD 4-5: HR, 3.4; 95% CI, 2.03-5.79; P < .001).

CONCLUSIONS

CKD severity is an essential predictor of perioperative and 1-year mortality after complex AAA repair, irrespective of the treatment modality, which may reflect the natural history of CKD. Consideration should be given to raising the threshold for elective AAA repair in patients with moderate to severe CKD and end-stage renal disease, given the high 1-year mortality rate.

Immune checkpoint inhibitors and acute kidney injury

As a new type of anti-tumor immunotherapy, immune checkpoint inhibitors (ICIs) have improved the prognosis of multiple malignancies. However, renal complications are becoming more frequent. Nephrotoxicity often manifests as acute kidney injury (AKI), and the most common histopathological type is acute tubulointerstitial nephritis (ATIN). Based on previous studies of the incidence and potential risk factors for nephrotoxicity, in this review, we describe the mechanism of AKI after ICIs treatment, summarize the incidence, risk factors, and outcomes of AKI, and discuss the diagnosis and management of immune checkpoint inhibitors-associated acute kidney injury (ICI-AKI). In addition, we review the current status of ICIs rechallenge and the therapeutic strategies of ICIs applied in kidney transplant recipients. Finally, we emphasize the importance of collaboration between nephrologists and oncologists to guide the treatment of ICIs and the management of renal complications.

Incidence, risk factors and outcome of acute kidney injury in critically ill COVID-19 patients in Tyrol, Austria: a prospective multicenter registry study

INTRODUCTION

Acute kidney injury is a frequent complication in critically ill patients with and without COVID-19. The aim of this study was to evaluate the incidence of, and risk factors for, acute kidney injury and its effect on clinical outcomes of critically ill COVID-19 patients in Tyrol, Austria.

METHODS

This multicenter prospective registry study included adult patients with a SARS-CoV-2 infection confirmed by polymerase chain reaction, who were treated in one of the 12 dedicated intensive care units during the COVID-19 pandemic from February 2020 until May 2022.

RESULTS

In total, 1042 patients were included during the study period. The median age of the overall cohort was 66 years. Of the included patients, 267 (26%) developed acute kidney injury during their intensive care unit stay. In total, 12.3% (n = 126) required renal replacement therapy with a median duration of 9 (IQR 3-18) days. In patients with acute kidney injury the rate of invasive mechanical ventilation was significantly higher with 85% (n = 227) compared to 41% (n = 312) in the no acute kidney injury group (p < 0.001). The most important risk factors for acute kidney injury were invasive mechanical ventilation (OR = 4.19, p < 0.001), vasopressor use (OR = 3.17, p < 0.001) and chronic kidney disease (OR = 2.30, p < 0.001) in a multivariable logistic regression analysis. Hospital and intensive care unit mortality were significantly higher in patients with acute kidney injury compared to patients without acute kidney injury (Hospital mortality: 52.1% vs. 17.2%, p < 0.001, ICU-mortality: 47.2% vs. 14.7%, p < 0.001).

CONCLUSION

As in non-COVID-19 patients, acute kidney injury is clearly associated with increased mortality in critically ill COVID-19 patients. Among known risk factors, invasive mechanical ventilation has been identified as an independent and strong predictor of acute kidney injury.

Tubulovascular protection from protease-activated receptor-1 depletion during AKI-to-CKD transition

BACKGROUND

Thromboembolic events are prevalent in chronic kidney disease (CKD) patients due to increased thrombin generation leading to a hypercoagulable state. We previously demonstrated that inhibition of protease-activated receptor-1 (PAR-1) by vorapaxar reduces kidney fibrosis.

METHODS

We used an animal model of unilateral ischemia-reperfusion injury-induced CKD to explore the tubulovascular crosstalk mechanisms of PAR-1 in acute kidney injury (AKI)-to-CKD transition.

RESULTS

During the early phase of AKI, PAR-1-deficient mice exhibited reduced kidney inflammation, vascular injury, and preserved endothelial integrity and capillary permeability. During the transition phase to CKD, PAR-1 deficiency preserved kidney function and diminished tubulointerstitial fibrosis via downregulated transforming growth factor-β/Smad signaling. Maladaptive repair in the microvasculature after AKI further exacerbated focal hypoxia with capillary rarefaction, which was rescued by stabilization of hypoxia-inducible factor and increased tubular vascular endothelial growth factor A in PAR-1-deficient mice. Chronic inflammation was also prevented with reduced kidney infiltration by both M1- and M2-polarized macrophages. In thrombin-induced human dermal microvascular endothelial cells (HDMECs), PAR-1 mediated vascular injury through activation of NF-κB and ERK MAPK pathways. Gene silencing of PAR-1 exerted microvascular protection via a tubulovascular crosstalk mechanism during hypoxia in HDMECs. Finally, pharmacologic blockade of PAR-1 with vorapaxar improved kidney morphology, promoted vascular regenerative capacity, and reduced inflammation and fibrosis depending on the time of initiation.

CONCLUSIONS

Our findings elucidate a detrimental role of PAR-1 in vascular dysfunction and profibrotic responses upon tissue injury during AKI-to-CKD transition and provide an attractive therapeutic strategy for post-injury repair in AKI.

Sick day management in people with chronic kidney disease: a scoping review

BACKGROUND

Use of certain medications during an acute illness may put patients at an increased risk of acute kidney injury (AKI). Patients with chronic kidney disease (CKD) are at higher risk of developing superimposed AKI. The aim of this scoping review is to collate and characterise existing evidence on sick day management considerations and practices during acute illness in people with CKD.

METHODS

We searched Embase, CINAHL, MEDLINE, International Pharmaceutical Abstract, Scopus, Google Scholar and grey literature sources. We followed the methodological framework for scoping reviews, while information was extracted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews. Findings are presented thematically.

RESULTS

Ten studies and seven guidelines met the inclusion criteria. Studies were targeted at patients, general practitioners, pharmacists, and nurses. The major themes identified included development and feasibility testing of a sick day management protocol, current practice of temporary medication discontinuation, and outcomes. Most guidelines provided recommendations for sick day management largely based on expert consensus. A digital intervention was deemed highly acceptable and easy to use, whereas patient handouts were more effective when provided along with dialogue with a health professional. While there is little evidence on the impact of sick day protocols on outcomes, a single randomised trial reported no significant association between sick day protocols and change in kidney function, AKI incidents or risk of hospitalisation.

CONCLUSION

The nascent literature on sick day management in patients with CKD revealed the limited available evidence to provide guidance on implementation and on outcomes. Future research needs to clarify sick day recommendations and assess their impact on clinical outcomes including prevention of superimposed AKI or hospitalisations, as well as to address barriers to implementation.

A Meta-Analysis of Proton Pump Inhibitor Use and the Risk of Acute Kidney Injury: Geographical Differences and Associated Factors

Proton pump inhibitors (PPIs) are widely prescribed in medical practice for the treatment of several gastrointestinal disorders. Previous epidemiology studies have reported the association between PPI use and the risk of AKI, although the magnitude of the association between PPIs and the risk of acute kidney injury (AKI) remains uncertain. Therefore, we conducted a meta-analysis to determine the relationship between PPI therapy and the risk of AKI. We systematically searched for relevant articles published before January 2023 on PubMed, Scopus, and Web of Science. In addition, we conducted a manual search of the bibliographies of potential articles. Two independent reviewers examined the appropriateness of all studies for inclusion. We pooled studies that compared the risk of AKI with PPI against their control using a random effect model. The search criteria based on PRISMA guidelines yielded 568 articles. Twelve observational studies included 2,492,125 individuals. The pooled adjusted RR demonstrated a significant positive association between PPI therapy and the risk of AKI (adjusted RR 1.75, 95% CI: 1.40-2.19, p < 0.001), and it was consistent across subgroups. A visual presentation of the funnel plot and Egger's regression test showed no evidence of publication bias. Our meta-analysis indicated that persons using PPIs exhibited an increased risk of AKI. North American individuals had a higher risk of AKI compared to Asian and European individuals. However, the pooled effect from observational studies cannot clarify whether the observed association is a causal effect or the result of some unmeasured confounding factors. Hence, the biological mechanisms underlying this association are still unclear and require further research.

Development of a Risk Score for AKI onset in COVID-19 Patients: COV-AKI Score

PURPOSE

Acute Kidney Injury (AKI) in COVID-19 patients is associated with increased morbidity and mortality. In the present study, we aimed to develop a prognostic score to predict AKI development in these patients.

MATERIALS AND METHODS

This was a retrospective observational study of 2334 COVID 19 patients admitted to 23 different hospitals in Brazil, between January 10th and August 30rd, 2020. The primary outcome of AKI was defined as any increase in serum creatinine (SCr) by 0.3 mg/dL within 48 h or a change in SCr by ≥ 1.5 times of baseline within 1 week, based on Kidney Disease Improving Global Outcomes (KDIGO) guidelines. All patients aged ≥ 18 y/o admitted with confirmed SARS-COV-2 infection were included. Discrimination of variables was calculated by the Receiver Operator Characteristic Curve (ROC curve) utilizing area under curve. Some continuous variables were categorized through ROC curve. The cutoff points were calculated using the value with the best sensitivity and specificity.

RESULTS

A total of 1131 patients with COVID-19 admitted to the ICU were included. Patients mean age was 52 ± 15,8 y/o., with a prevalence of males 60% (n = 678). The risk of AKI was 33% (n = 376), 78% (n = 293) of which did not require dialysis. Overall mortality was 11% (n = 127), while for AKI patients, mortality rate was 21% (n = 80). Variables selected for the logistic regression model and inclusion in the final prognostic score were the following: age, diabetes, ACEis, ARBs, chronic kidney disease and hypertension.

CONCLUSION

AKI development in COVID 19 patients is accurately predicted by common clinical variables, allowing early interventions to attenuate the impact of AKI in these patients.

Cystatin C and derived measures of renal function as risk factors for mortality and acute kidney injury in sepsis - A post-hoc analysis of the FINNAKI cohort

PURPOSE

To assess the association between cystatin C-derived estimates of kidney function and mortality and acute kidney injury (AKI) in sepsis.

MATERIALS AND METHODS

Post-hoc analysis of sepsis patients in the FINNAKI-cohort (n = 802). Primary outcome was 90-day mortality. We measured plasma cystatin C and creatinine at intensive care unit (ICU) admission and estimated glomerular filtration rates (eGFR_cys, eGFR_crea) and shrunken pore syndrome (SPS; defined as eGFR_cys/eGFR_crea ratio < 0.7). Associations were assessed using Cox- or logistic regression.

RESULTS

Increased cystatin C and decreased eGFR_cys were associated with mortality in unadjusted analyses and in analyses adjusted for illness severity and creatinine. Hazard ratios (HRs) in unadjusted analyses were 3.30 (95% CI; 2.12-5.13, p < 0.001) and 3.26 (95% CI; 2.12-5.02, p < 0.001) respectively. SPS was associated with mortality in an unadjusted- (HR 1.78, 95% CI; 1.33-2.37, p < 0.001) and in an adjusted analysis (HR 1.54, 95% CI; 1.07-2.22, p = 0.021). All cystatin C-derived measures were associated with mortality also after adjustment for AKI development. Cystatin C was associated with AKI in unadjusted analyses but not in analyses adjusted for creatinine.

CONCLUSION

Cystatin C and derived measures of kidney function at ICU admission are associated with an increased 90-day mortality. Increased AKI incidence does not fully explain this association.

Acute kidney injury without need for dialysis, incidence, its impact on long-term stroke survival and progression to chronic kidney disease

INTRODUCTION

Patients who had a stroke are at increased risk of sepsis, dehydration and fluctuations in blood pressure, which may result in acute kidney injury (AKI). The impact of AKI on long-term stroke survival has not been studied well.

OBJECTIVE

We aimed to identify incidence of AKI during acute stroke, follow-up period and its impact on long-term survival and development of chronic kidney disease (CKD).

DESIGN, SETTING AND PARTICIPANTS

Retrospective analysis of patients who had a stroke admitted at the rehabilitation facility in Changi General Hospital, Singapore, between June 2008 and May 2017, with median follow-up of 141 (95% CI 120 to 163) months.

OUTCOME MEASURES AND RESULTS OF UNIVARIATE ANALYSIS

Total 681 patients, median age (63.6) years, 173 (28%) died during follow-up. Elevated blood urea (3.02, 95% CI 2.17 to 4.22; p≤0.001) and creatinine (1.96, 95% CI 1.50 to 2.57; p≤0.001) during stroke affected survival adversely.Excluding patients with CKD, we analysed the remaining 617 patients. AKI was noted in 75 (12.15%) patients during the index admission, and it affected survival adversely (2.16, 95% CI 1.49 to 3.13; p<0.001). Of the patients with AKI, 21 of 75 (28%) progressed to CKD over a median follow-up of 40.7 months.

CONCLUSIONS

We found AKI during stroke admission was associated with increased mortality as compared with those without AKI on univariate analysis. AKI without need of renal replacement therapy was also associated with progression to CKD in this cohort. This suggests that patients with AKI need to have their renal function monitored longitudinally for development of CKD.

Current kidney function parameters overestimate kidney tissue repair in reversible experimental kidney disease

Although underlying mechanisms and the clinical course of kidney disease progression are well described, less is known about potential disease reversibility. Therefore, to analyze kidney recovery, we adapted a commonly used murine chronic kidney disease (CKD) model of 2,8- dihydroxyadenine (2,8-DHA) crystal-induced nephropathy to study disease recovery and efficacy of disease-modifying interventions. The recovery phase after CKD was characterized by improved kidney function after two weeks which remained stable thereafter. By contrast, even after eight weeks recovery, tubular injury and inflammation were only partially reduced and fibrosis persisted. Deep-learning-based histologic analysis of 8,604 glomeruli and 596,614 tubular cross sections revealed numerous tubules had undergone either prominent dilation or complete atrophy, leading to atubular glomeruli and irreversible nephron loss. We confirmed these findings in a second CKD model, reversible unilateral ureteral obstruction, in which a rapid improvement of glomerular filtration rate during recovery also did not reflect the permanent histologic kidney injury. In 2,8-DHA nephropathy, increased drinking volume was highly effective in disease prevention. However, in therapeutic approaches, high fluid intake was only effective in moderate but not severe CKD and established tissue injury was again poorly reflective of kidney function parameters. The injury was particularly localized in the medulla, which is often not analyzed. Thus, recovery after crystal- or obstruction-induced CKD is characterized by ongoing tissue injury, fibrosis, and nephron loss, but not reflected by standard measures of kidney function. Hence, our data might aid in designing kidney recovery studies and suggest the need for biomarkers specifically monitoring intra-kidney tissue injury.

Atrial Fibrillation and Chronic Kidney Disease-A Risky Combination for Post-Contrast Acute Kidney Injury

Atrial fibrillation (AF) symptoms may mimic coronary artery disease (CAD) which reflects the difficulties in qualifying AF patients for invasive diagnostics. A substantial number of coronary angiographies may be unnecessary or even put patients at risk of post-contrast acute kidney injury (PC-AKI), especially patients with chronic kidney disease (CKD). We aimed to investigate the hypothesis indicating higher prevalence of PC-AKI in patients with AF scheduled for coronary angiography. The study population comprised of 8026 patients referred for elective coronarography including 1621 with AF. In the comparison of prevalence of PC-AKI in distinguished groups we can see that kidney impairment was twice more frequent in patients with AF in both groups with CKD (CKD (+)/AF (+) 6.24% vs. CKD (+)/AF (−) 3.04%) and without CKD (CKD (−)/AF (+) 2.32% vs. CKD (−)/AF (−) 1.22%). In our study, post-contrast acute kidney disease is twice more frequent in patients with AF, especially in subgroup with chronic kidney disease scheduled for coronary angiography. Additionally, having in mind results of previous studies stating that AF is associated with non-obstructive coronary lesions on angiography, patients with AF and CKD may be unnecessarily exposed to contrast agent and possible complications.

Acute kidney injury and its progression in hospitalized patients-Results from a retrospective multicentre cohort study with a digital decision support system

In this retrospective multicentric cohort study, we evaluate the potential benefits of a clinical decision support system (CDSS) for the automated detection of Acute kidney injury (AKI). A total of 80,389 cases, hospitalized from 2017 to 2019 at a tertiary care hospital (University of Leipzig Medical Center (ULMC)) and two primary care hospitals (Muldentalkliniken (MTL)) in Germany, were enrolled. AKI was defined and staged according to the Kidney disease: improving global outcomes (KDIGO) guidelines. Clinical and laboratory data was automatically collected from electronic patient records using the frameworks of the CDSS. In our cohort, we found an overall AKI incidence proportion of 12.1%. We identified 6,393/1,703/1,604 cases as AKI stage 1/2/3 (8.0%/2.1%/2.0%, respectively). Administrative coding with N17 (ICD-10-GM) was missing in 55.8% of all AKI cases with the potential for additional diagnosis related groups (DRG) reimbursement of 1,204,200 € in our study. AKI was associated with higher hospital mortality, increased length of hospitalisation and more frequent need of renal replacement therapy. A total of 19.1% of AKI cases (n = 1,848) showed progression to higher AKI stages (progressive AKI) during hospitalization. These cases presented with considerably longer hospitalization, higher rates of renal replacement therapy and increased mortality (p<0.001, respectively). Furthermore, progressive AKI was significantly associated with sepsis, shock, liver cirrhosis, myocardial infarction, and cardiac insufficiency. AKI, and especially its progression during hospitalization, is strongly associated with adverse outcomes. Our automated CDSS enables timely detection and bears potential to improve AKI outcomes, notably in cases of progressive AKI.

CKD Prevalence in the Military Health System: Coded Versus Uncoded CKD

Rationale & Objective

Chronic kidney disease (CKD) is common but often goes unrecorded.

Study Design

Cross-sectional.

Setting & Participants

Military Health System (MHS) beneficiaries aged 18 to 64 years who received care during fiscal years 2016 to 2018.

Predictors

Age, sex, active duty status, race, diabetes, hypertension, and numbers of kidney test results.

Outcomes

We defined CKD by International Classification of Diseases, Tenth Revision (ICD-10) code and/or a positive result on a validated electronic phenotype that uses estimated glomerular filtration rate and measures of proteinuria with evidence of chronicity. We defined coded CKD by the presence of an ICD-10 code. We defined uncoded CKD by a positive e-phenotype result without an ICD-10 code.

Analytical Approach

We compared coded and uncoded populations using 2-tailed t tests (continuous variables) and Pearson χ² test for independence (categorical variables).

Results

The MHS population included 3,330,893 beneficiaries. Prevalence of CKD was 3.2%, based on ICD code and/or positive e-phenotype result. Of those identified with CKD, 63% were uncoded. Compared with beneficiaries with coded CKD, those with uncoded CKD were younger (aged 45 ± 13 vs 52 ± 11 years), more often women (54.4% vs 37.6%) and active duty (20.2% vs 12.5%), and less often of Black race (18.5% vs 31.5%) or with diabetes (23.5% vs 43.5%) or hypertension (46.6% vs 77.1%; P < 0.001). Beneficiaries with coded (vs uncoded) CKD had greater numbers of kidney test results (P < 0.001).

Limitations

Use of cross-sectional administrative data prevents inferences about causality. The CKD e-phenotype may fail to capture CKD in individuals without laboratory data and may underestimate CKD.

Conclusions

The prevalence of CKD in the MHS is ~3.2%. Beneficiaries with well-known CKD risk factors, such as older age, male sex, Black race, diabetes, and hypertension, were more likely to be coded, suggesting that clinicians may be missing CKD in groups traditionally considered lower risk, potentially resulting in suboptimal care.

Immunotherapy-Induced Acute Tubulointerstitial Nephritis

Due to its minimal side-effect profile, immunotherapy has become a popular choice for the treatment of advanced melanoma as compared to conventional chemotherapy. The most common side effects associated with immunotherapy include gastrointestinal, pulmonary, and dermatologic manifestations. However, there have been very few documented occurrences of nephrotoxic side effects. We present a case of a 73-year-old male with a past medical history of chronic kidney disease (CKD) stage 3A, metastatic uveal melanoma, and gastroesophageal reflux disease on pantoprazole who arrived at the intensive care unit with altered mental status and creatinine of 27 gm/dl (baseline creatinine of 3 gm/dl about one year prior), after receiving his first dose of ipilimumab and nivolumab approximately 21 days prior. Kidney biopsy demonstrated acute tubulointerstitial nephritis (ATIN). This case highlights the importance of recognizing acute tubulointerstitial nephritis as a side effect of immunotherapy for prompt diagnosis and early treatment.

Acute Kidney Injury and Renal Replacement Therapy in Critically Ill COVID-19 Patients: Risk Factors and Outcomes: A Single-Center Experience in Brazil

Background

Critically ill patients with COVID-19 may develop multiple organ dysfunction syndrome, including acute kidney injury (AKI). We report the incidence, risk factors, associations, and outcomes of AKI and renal replacement therapy (RRT) in critically ill COVID-19 patients.

Methods

We performed a retrospective cohort study of adult patients with COVID-19 diagnosis admitted to the intensive care unit (ICU) between March 2020 and May 2020. Multivariable logistic regression analysis was applied to identify risk factors for the development of AKI and use of RRT. The primary outcome was 60-day mortality after ICU admission.

Results

101 (50.2%) patients developed AKI (72% on the first day of invasive mechanical ventilation [IMV]), and thirty-four (17%) required RRT. Risk factors for AKI included higher baseline Cr (OR 2.50 [1.33–4.69], p = 0.005), diuretic use (OR 4.14 [1.27–13.49], p = 0.019), and IMV (OR 7.60 [1.37–42.05], p = 0.020). A higher C-reactive protein level was an additional risk factor for RRT (OR 2.12 [1.16–4.33], p = 0.023). Overall 60-day mortality was 14.4% {23.8% (n = 24) in the AKI group versus 5% (n = 5) in the non-AKI group (HR 2.79 [1.04–7.49], p = 0.040); and 35.3% (n = 12) in the RRT group versus 10.2% (n = 17) in the non-RRT group, respectively (HR 2.21 [1.01–4.85], p = 0.047)}.

Conclusions

AKI was common among critically ill COVID-19 patients and occurred early in association with IMV. One in 6 AKI patients received RRT and 1 in 3 patients treated with RRT died in hospital. These findings provide important prognostic information for clinicians caring for these patients.

Renal Dysfunction following Direct Current Cardioversion of Atrial Fibrillation: Incidence and Risk Factors

INTRODUCTION

Emerging data suggest that cardioversion for atrial fibrillation (AF) may be associated with acute kidney injury (AKI). However, limited data are available regarding the incidence and risk factors for AKI after direct current cardioversion (DCCV) of AF.

METHODS

All patients undergoing DCCV at Mayo Clinic between 2001 and 2012 for AF were prospectively enrolled in a database. All patients with serum creatinine (SCR) values pre- and post-cardioversion were reviewed for AKI, defined as a ≥25% decline in eGFR (estimated glomerular filtration rate) from baseline value within 7 days of the DCCV.

RESULTS

Of the 6,427 eligible patients, 1,256 (19.5%) patients had pre- and post-DCCV SCR available and formed the cohort under study. The mean age was 70.4 (SD 11.7) years, and 67.3% were male. During the study period, 131 (10.4%) patients suffered from AKI following DCCV. AKI was independently associated with inpatient status (OR 26.79; 95% CI 3.69-194.52), CHA2DS2-VASc score (OR 1.25; 95% CI 1.11-1.41), prior use of diuretics (OR 1.59; 95% CI 1.03-2.46), and absence of CKD (OR 1.61; 95% CI 1.04-2.49), and was independent of the success of the DCCV. None of the patients required acute dialysis during the study outcome period.

CONCLUSION

AKI following DCCV of AF is common, self-limited, and without the need for replacement therapies.

Delayed Fever and Acute Kidney Injury in Patients with Urinary Tract Infection

The presence of fever has long been a warning sign of severe urinary tract infection (UTI). However, we previously identified that inpatients with afebrile UTI had an increased risk of developing acute kidney injury (AKI). After expanding this cohort, 1132 inpatients with UTI diagnosed between January 2006 and April 2019 were analyzed. Overall, 159 (14%) of these patients developed AKI; bacteremia, urolithiasis, septic shock, hypertension, lower baseline renal function, marked leukocytosis, and the absence of fever were independently linked to AKI. When we further studied the cohort of inpatients with fever during hospitalization, we identified a group of "delayed fever" UTI inpatients who did not have fever as their initial presentation. Compared to patients presenting with fever at the emergency department, patients with delayed fever tended to be younger and have less frequent infection with Escherichia coli, more frequent AKI, upper tract infection, and a longer hospital stay. Despite the initial absence of fever, these patients demonstrated larger extents of elevations in both serum white blood cell counts and C-reactive protein levels. In short, besides UTI patients with lower baseline renal function that remain afebrile during their hospital stay, clinical awareness of the increased incidence of AKI in younger patients with "delayed fever" should also be noted.

Risk factors and mortality in patients with sepsis, septic and non septic acute kidney injury in ICU

Acute kidney injury (AKI) has an incidence rate of 5-6% among intensive care unit (ICU) patients and sepsis is the most frequent etiology.

Non-steroidal anti-inflammatory drug (NSAID) therapy in patients with hypertension, cardiovascular, renal or gastrointestinal comorbidities: joint APAGE/APLAR/APSDE/APSH/APSN/PoA recommendations

BACKGROUND

Non-steroidal anti-inflammatory drugs (NSAIDs) are one of the most commonly prescribed medications, but they are associated with a number of serious adverse effects, including hypertension, cardiovascular disease, kidney injury and GI complications.

OBJECTIVE

To develop a set of multidisciplinary recommendations for the safe prescription of NSAIDs.

METHODS

Randomised control trials and observational studies published before January 2018 were reviewed, with 329 papers included for the synthesis of evidence-based recommendations.

RESULTS

Whenever possible, a NSAID should be avoided in patients with treatment-resistant hypertension, high risk of cardiovascular disease and severe chronic kidney disease (CKD). Before treatment with a NSAID is started, blood pressure should be measured, unrecognised CKD should be screened in high risk cases, and unexplained iron-deficiency anaemia should be investigated. For patients with high cardiovascular risk, and if NSAID treatment cannot be avoided, naproxen or celecoxib are preferred. For patients with a moderate risk of peptic ulcer disease, monotherapy with a non-selective NSAID plus a proton pump inhibitor (PPI), or a selective cyclo-oxygenase-2 (COX-2) inhibitor should be used; for those with a high risk of peptic ulcer disease, a selective COX-2 inhibitor plus PPI are needed. For patients with pre-existing hypertension receiving renin-angiotensin system blockers, empirical addition (or increase in the dose) of an antihypertensive agent of a different class should be considered. Blood pressure and renal function should be monitored in most cases.

CONCLUSION

NSAIDs are a valuable armamentarium in clinical medicine, but appropriate recognition of high-risk cases, selection of a specific agent, choice of ulcer prophylaxis and monitoring after therapy are necessary to minimise the risk of adverse events.

Evaluating the risk of hyperkalaemia and acute kidney injury with cotrimoxazole: a retrospective observational study

OBJECTIVES

Increasing antimicrobial resistance has renewed interest in older, less used antimicrobials. Cotrimoxazole shows promise; however, hyperkalaemia and acute kidney injury (AKI) are potential complications. Identifying risk factors for and quantification of these events is required for safe use. This study aimed to evaluate predictors of cotrimoxazole-associated AKI and hyperkalaemia in a clinical setting.

METHODS

Patients prescribed cotrimoxazole were identified using electronic healthcare records over 3 years (1 April 2016 to 31 March 2019). Individual risk factors were recognized. Serum creatinine and potassium trends were analysed over the subsequent 21 days. AKI and patients with hyperkalaemia were classified using Kidney Disease Improving Global Outcomes (KDIGO) and laboratory criteria. Univariate and multiple logistic regression analyses were performed.

RESULTS

Among 214 patients prescribed cotrimoxazole, 42 (19.6%, 95% confidence interval (CI) 14.6-25.7) met AKI criteria and 33 (15.4%, 95% CI 11.0-21.1) developed hyperkalaemia. Low baseline estimated glomerular filtration rate (<60 mL/min/1.73 m², odds ratio (OR) 7.78, 95% CI 3.57-16.13, p < 0.0001) and cardiac disorders (OR 2.40, 95% CI 1.17-4.82, p 0.011) predicted AKI, while low baseline estimated glomerular filtration rate (<60 mL/min/1.73 m², OR 6.80, 95% CI 3.09-15.06, p < 0.0001) and higher baseline serum potassium (p 0.001) predicted hyperkalaemia. Low-dose cotrimoxazole (<1920 mg/d) was associated with lower AKI and hyperkalaemia risk (p 0.007 and 0.019 respectively). Early (within the first 2-4 days of therapy) serum creatinine changes predicted AKI (OR 3.65, 95% CI 1.73-7.41, p 0.001), and early serum potassium changes predicted hyperkalaemia (>0.6 mmol/L, OR 2.47, 95% CI 1.14-5.27, p 0.0236).

CONCLUSIONS

Cotrimoxazole-associated AKI and hyperkalaemia is frequent and dose dependent. Renal function, serum potassium and preexisting cardiac disorders should be evaluated before prescribing cotrimoxazole. Serum creatinine and potassium monitoring within first 2 to 4 days of treatment to identify susceptible patients is recommended, and the lowest effective dose ought to be prescribed.

SLPI - a Biomarker of Acute Kidney Injury after Open and Endovascular Thoracoabdominal Aortic Aneurysm (TAAA) Repair

Acute kidney injury (AKI) is a relevant complication following thoracoabdominal aortic aneurysm repair (TAAA). Biomarkers, such as secretory leucocyte peptidase inhibitor (SLPI), may enable a more accurate diagnosis. In this study, we tested if SLPI measured in serum is an appropriate biomarker of AKI after TAAA repair. In a prospective observational single-center study including 33 patients (51.5% women, mean age 63.0 ± 16.2 years) undergoing open and endovascular aortic aneurysm repair in 2017, SLPI was measured peri-operatively (until 72 h after surgery). After surgery, the postoperative complications AKI, as defined according to the KDIGO diagnostic criteria, sepsis, death, MACE (major cardiovascular events) and, pneumonia were assessed. In a subgroup analysis, patients with preexisting kidney disease were excluded. Of 33 patients, 51.5% (n = 17) of patients developed AKI. Twelve hours after admission to the intensive care unit (ICU), SLPI serum levels were significantly increased in patients who developed AKI. Multivariable logistic regression revealed a significant association between SLPI 12 hours after admission to ICU and AKI (P = 0.0181, OR = 1.055, 95% CI = 1.009-1.103). The sensitivity of SLPI for AKI prediction was 76.47% (95% CI = 50.1-93.2) and the specificity was 87.5% (95% CI = 61.7-98.4) with an AUC = 0.838 (95% CI = 0.7-0.976) for an optimal cut-off 70.03 ng/ml 12 hours after surgery. In patients without pre-existing impaired renal function, an improved diagnostic quality of SLPI for AKI was observed (Sensitivities of 45.45-91.67%, Specificities of 77.7-100%, AUC = 0.716-0.932). There was no association between perioperative SLPI and the incidence of sepsis, death, MACE (major cardiovascular events), pneumonia. This study suggests that SLPI might be a post-operative biomarker of AKI after TAAA repair, with a superior diagnostic accuracy for patients without preexisting impaired renal function.

Fenestrated-branched endovascular aortic repair in patients with chronic kidney disease

OBJECTIVE

Renal function impairment is a common complication after open repair of complex abdominal aortic aneurysms and thoracoabdominal aortic aneurysms (TAAAs). The purpose of this study was to assess renal perioperative outcomes and renal function deterioration after fenestrated-branched endovascular aneurysm repair (F/BEVAR) in patients with chronic kidney disease (CKD).

METHODS

The study included 186 patients who underwent F/BEVAR between 2013 and 2018 for suprarenal, juxtarenal, and type I to type IV TAAAs. Glomerular filtration rate (GFR) was calculated using the Modification of Diet in Renal Disease (MDRD) study equation. Postoperative acute kidney injury (AKI) and CKD were defined using RIFLE criteria (Risk, Injury, Failure, Loss, and End-stage renal disease) and CKD staging system (stage ≥3, GFR <60 mL/min/1.73 m²), respectively. For those without baseline CKD, renal decline was defined as a drop in GFR <60 mL/min/1.73 m² (ie, progression to CKD stage 3 or higher). For patients with baseline renal dysfunction, GFR decline ≥20% or progression in CKD stage (ie, from stage 3 to stage 4) was considered renal decline.

RESULTS

CKD was present in 83 patients (44.6%). Postoperative AKI was diagnosed in 27 patients (14.5%); 13 (48.1%) had history of CKD and 14 (51.9%) had adequate renal function preoperatively (P = .8). None of these patients required permanent renal replacement therapy. Intraoperative technical success was 100%. Overall 30-day mortality was 1.1%. There was no difference in 30-day mortality in patients with (1.2%) and without (1.0%) CKD (P = .5). During a median follow-up time of 12 months (interquartile range, 6-23 months), renal decline was observed in 21 patients (25.3%) with previous CKD and in 11 patients (10.6%) without CKD (P = .01). Among patients with previous CKD, 18 patients (9%) progressed from stage 3 CKD to stage 4. In patients with progression in CKD stage, two (5%) had renal stent stenosis requiring restenting. Among patients with renal decline, 13 had juxtarenal aneurysms (21.3%), 27 had suprarenal aneurysms (44.3%), and 21 had TAAAs (34.3%; P = .4). Subset analysis of patients who developed AKI in the immediate postoperative period found that patients with a history of CKD were less likely to experience freedom from renal decline.

CONCLUSIONS

F/BEVAR is an effective and safe procedure for patients with complex abdominal aortic aneurysms and TAAAs, even among patients with CKD. The frequency of AKI was not affected by pre-existing CKD. Midterm outcomes demonstrated that progression of CKD was more frequent among patients with pre-existing CKD, but permanent renal replacement therapy was not required. Anatomic extent of aneurysms did not affect CKD progression. CKD patients are susceptible to renal decline over time if they experience AKI in the postoperative period. Therefore, preventing AKI in the postoperative period should be regarded as a priority. Long-term effects of CKD after F/BEVAR remain to be elucidated.

Clinical Features and Outcomes of Immune Checkpoint Inhibitor-Associated AKI: A Multicenter Study

BACKGROUND

Despite increasing recognition of the importance of immune checkpoint inhibitor-associated AKI, data on this complication of immunotherapy are sparse.

METHODS

We conducted a multicenter study of 138 patients with immune checkpoint inhibitor-associated AKI, defined as a ≥2-fold increase in serum creatinine or new dialysis requirement directly attributed to an immune checkpoint inhibitor. We also collected data on 276 control patients who received these drugs but did not develop AKI.

RESULTS

Lower baseline eGFR, proton pump inhibitor use, and combination immune checkpoint inhibitor therapy were each independently associated with an increased risk of immune checkpoint inhibitor-associated AKI. Median (interquartile range) time from immune checkpoint inhibitor initiation to AKI was 14 (6-37) weeks. Most patients had subnephrotic proteinuria, and approximately half had pyuria. Extrarenal immune-related adverse events occurred in 43% of patients; 69% were concurrently receiving a potential tubulointerstitial nephritis-causing medication. Tubulointerstitial nephritis was the dominant lesion in 93% of the 60 patients biopsied. Most patients (86%) were treated with steroids. Complete, partial, or no kidney recovery occurred in 40%, 45%, and 15% of patients, respectively. Concomitant extrarenal immune-related adverse events were associated with worse renal prognosis, whereas concomitant tubulointerstitial nephritis-causing medications and treatment with steroids were each associated with improved renal prognosis. Failure to achieve kidney recovery after immune checkpoint inhibitor-associated AKI was independently associated with higher mortality. Immune checkpoint inhibitor rechallenge occurred in 22% of patients, of whom 23% developed recurrent associated AKI.

CONCLUSIONS

This multicenter study identifies insights into the risk factors, clinical features, histopathologic findings, and renal and overall outcomes in patients with immune checkpoint inhibitor-associated AKI.

Development and internal validation of a prediction model for hospital-acquired acute kidney injury

Background

Predictive models and clinical risk scores for hospital-acquired acute kidney injury (AKI) are mainly focused on critical and surgical patients. We have used the electronic clinical records from a tertiary care general hospital to develop a risk score for new-onset AKI in general inpatients that can be estimated automatically from clinical records.

Methods

A total of 47 466 patients met inclusion criteria within a 2-year period. Of these, 2385 (5.0%) developed hospital-acquired AKI. Step-wise regression modelling and Bayesian model averaging were used to develop the Madrid Acute Kidney Injury Prediction Score (MAKIPS), which contains 23 variables, all obtainable automatically from electronic clinical records at admission. Bootstrap resampling was employed for internal validation. To optimize calibration, a penalized logistic regression model was estimated by the least absolute shrinkage and selection operator (lasso) method of coefficient shrinkage after estimation.

Results

The area under the curve of the receiver operating characteristic curve of the MAKIPS score to predict hospital-acquired AKI at admission was 0.811. Among individual variables, the highest odds ratios, all >2.5, for hospital-acquired AKI were conferred by abdominal, cardiovascular or urological surgery followed by congestive heart failure. An online tool (http://www.bioestadistica.net/MAKIPS.aspx) will facilitate validation in other hospital environments.

Conclusions

MAKIPS is a new risk score to predict the risk of hospital-acquired AKI, based on variables present at admission in the electronic clinical records. This may help to identify patients who require specific monitoring because of a high risk of AKI.

Impact on Outcomes across KDIGO-2012 AKI Criteria According to Baseline Renal Function

Acute kidney injury (AKI) and Chronic Kidney Disease (CKD) are global health problems. The pathophysiology of acute-on-chronic kidney disease (AoCKD) is not well understood. We aimed to study clinical outcomes in patients with previous normal (pure acute kidney injury; P-AKI) or impaired kidney function (AoCKD) across the 2012 Kidney Disease Improving Global Outcomes (KDIGO) AKI classification. We performed a retrospective study of patients with AKI, divided into P-AKI and AoCKD groups, evaluating clinical and epidemiological features, distribution across KDIGO-2012 criteria, in-hospital mortality and need for dialysis. One thousand, two hundred and sixty-nine subjects were included. AoCKD individuals were older and had higher comorbidity. P-AKI individuals fulfilled more often the serum creatinine (SCr) ≥ 3.0× criterion in AKI-Stage3, AoCKD subjects reached SCr ≥ 4.0 mg/dL criterion more frequently. AKI severity was associated with in-hospital mortality independently of baseline renal function. AoCKD subjects presented higher mortality when fulfilling AKI-Stage1 criteria or SCr ≥ 3.0× criterion within AKI-Stage3. The relationship between mortality and associated risk factors, such as the net increase of SCr or AoCKD status, fluctuated depending on AKI stage and stage criteria sub-strata. AoCKD patients that fulfil SCr increment rate criteria may be exposed to more severe insults, possibly explaining the higher mortality. AoCKD may constitute a unique clinical syndrome. Adequate staging criteria may help prompt diagnosis and administration of appropriate therapy.

Risk Evaluation for Acute Kidney Injury Induced by the Concomitant Use of Valacyclovir, Analgesics, and Renin-Angiotensin System Inhibitors: The Detection of Signals of Drug-Drug Interactions

Background: Drug-related acute kidney disease is a common side effect of valacyclovir (VACV) treatment. Although analgesics are frequently administered concomitantly with VACV to treat the pain of herpes zoster, the differences between nonsteroidal anti-inflammatory drugs (NSAIDs) and acetaminophen in relation to VACV-related acute kidney injury (AKI) are unclear. The risk for AKI with concomitant use of VACV and renin–angiotensin system (RAS) inhibitors that can cause AKI via a similar mechanism to NSAIDs is also unknown. We therefore evaluated the association between concomitant use of these drugs and VACV-related AKI, which was characterized according to the Japanese Adverse Drug Event Report (JADER) database.

Methods: We analyzed data from the JADER database, which is a spontaneous reporting system. The reporting odds ratio was used to evaluate the signals of AKI.

Results: A high proportion of VACV-related AKI cases occurred in summer. There was an increase in AKI signal in cases with concomitant use of VACV and NSAIDs, while no increase was detected in cases with concomitant use of VACV and acetaminophen. AKI events in cases with concomitant use of VACV and NSAIDs were more frequent in older and female patients and those with hypertension. Additionally, a signal increase for VACV-related AKI was observed with concomitant use of RAS inhibitors, with or without NSAIDs.

Conclusions: We identified a seasonal variation in VACV-related AKI. Additionally, our findings indicate that acetaminophen might represent a safer analgesic than NSAIDs with respect to VACV-related AKI. We also identified candidate risk factors for AKI with concomitant use of NSAIDs, such as older age, female sex, and hypertension. Although further studies are warranted, our findings highlight the need to consider concomitant drug use and seasonal factors that lead to urinary output loss so that VACV-related AKI can be avoided.

IL-6-producing Renal Cell Carcinoma Causing Renal and Endocrine Paraneoplastic Syndromes

An 83-year-old man with stable chronic kidney disease (CKD) exhibited a sudden increase in urinary N-acetyl-β-D-glucosaminidase and protein excretion, suggesting aggravated kidney damage. Simultaneously, he lost diabetic control, requiring up to 54 units of insulin daily. A detailed examination revealed the presence of renal cell carcinoma, which was surgically resected and confirmed to be interleukin-6-positive by immunohistochemistry. Postoperatively, his uni-nephrectomy necessitated hemodialysis, but the patient's insulin resistance was ameliorated; no medication was required to control diabetes, suggesting that the tumor had caused the insulin resistance. This report describes a case of a tumor secreting interleukin-6, which affects both the control of diabetes and CKD progression.

Under-recognized post-stroke acute kidney injury: risk factors and relevance for stroke outcome of a frequent comorbidity

BACKGROUND

Acute kidney injury (AKI) is emerging as a predictor of poor stroke outcome, however, it is often not recognized. The aim of our study was to evaluate post-stroke AKI burden, AKI risk factors and their influence in post-stroke outcome.

METHODS

From 2013 to 2016, 440 individuals with stroke diagnosis admitted in Stroke Unit, Foundation IRCCS Policlinico San Matteo (Pavia, Italy), were retrospectively enrolled. AKI cases identified by KDIGO criteria through the electronic database and hospital chart review were compared with the ones reported in discharge letters or in administrative hospital data base. Mortality data were provided by Agenzia Tutela della Salute of Pavia.

RESULTS

We included 430 patients in the analysis. Median follow-up was 19.2 months. We identified 79 AKI cases (18% of the enrolled patients, 92% classified as AKI stage 1), a fivefold higher number of cases than the ones reported at discharge. 37 patients had AKI at the admission in the hospital, while 42 developed AKI during the hospitalization. Cardioembolic (p = 0.01) and hemorrhagic (p = 0.01) stroke types were associated with higher AKI risk. Admission National Institutes of Health Stroke Scale (NIHSS, p < 0.05) and Charlson Comorbidity Index (p < 0.01) were independently associated with overall AKI, while admission NIHSS (p < 0.05) and eGFR (p < 0.005) were independently associated with AKI developed during the hospitalization. AKI was associated to longer in-hospital stay (p = 0.01), worse Rankin Neurologic Disability Score at discharge (p < 0.0001) and discharge disposition other than home (p = 0.03). AKI was also independently associated to higher in-hospital mortality (OR 3.9 95% CI 1.2-12.9 p = 0.023) but not with long-term survival.

CONCLUSIONS

Post-stroke AKI diagnosis needs to be improved by strictly monitoring individuals with cardioembolic or hemorrhagic stroke, reduced kidney function, higher Charlson Comorbidity Index and worse NIHSS at presentation.

Mild to moderate proteinuria is a heralding sign for acute kidney injury and mortality for intensive care unit patients

Background/aim

Lack of early predictors of acute kidney injury is currently delaying timely diagnosis.This study was done to evaluate the relationship between mild to moderate proteinuria and incidence of acute kidney injury (AKI) and 28-day mortality in intensive care unit (ICU) patients.

Materials and methods

This observational, retrospective study was conducted in the internal medicine ICU. A total of 796 patients were screened and 525 patients were used for this analysis. Proteinuria was measured by urine dipstick test. AKI was defined according to the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines.

Results

Patients with dipstick urine protein positivity on admission had higher proportion of AKI and 28-day mortality compared to dipstick urine protein negative group [164 (59.6%) vs. 111 (44.4%) and 101 (36.7%) vs. 54 (21.6%), P = 0.01 and P < 0.01, respectively]. Urine dipstick protein positivity was also a significant predictor of 28-day mortality in patients with GFR > 60 mL/min (hazard ratio: 1.988, 95% confidence interval 1.380–2.862).

Conclusion

Proteinuria before ICU admission is a risk factor for development of AKI within seven days of ICU stay and also is a risk factor for 28-day mortality, even in patients with GFR > 60 mL/min.

Deceased-donor acute kidney injury is not associated with kidney allograft failure

Deceased-donor acute kidney injury (AKI) is associated with organ discard and delayed graft function, but data on longer-term allograft survival are limited. We performed a multicenter study to determine associations between donor AKI (from none to severe based on AKI Network stages) and all-cause graft failure, adjusting for donor, transplant, and recipient factors. We examined whether any of the following factors modified the relationship between donor AKI and graft survival: kidney donor profile index, cold ischemia time, donation after cardiac death, expanded-criteria donation, kidney machine perfusion, donor-recipient gender combinations, or delayed graft function. We also evaluated the association between donor AKI and a 3-year composite outcome of all-cause graft failure or estimated glomerular filtration rate ≤ 20 mL/min/1.73 m² in a subcohort of 30% of recipients. Among 2,430 kidneys transplanted from 1,298 deceased donors, 585 (24%) were from donors with AKI. Over a median follow-up of 4.0 years, there were no significant differences in graft survival by donor AKI stage. We found no evidence that pre-specified variables modified the effect of donor AKI on graft survival. In the subcohort, donor AKI was not associated with the 3-year composite outcome. Donor AKI was not associated with graft failure in this well-phenotyped cohort. Given the organ shortage, the transplant community should consider measures to increase utilization of kidneys from deceased donors with AKI.

Enhanced renal ischemia-reperfusion injury in aging and diabetes

The incidence and severity of acute kidney injury is increased in patients with diabetes and with aging. However, the mechanisms involved have not been clearly established. The present study examined the effects of aging and diabetes on the severity of renal ischemia-reperfusion (IR) injury in Sprague-Dawley (SD) and type 2 diabetic (T2DN) rats. T2DN rats develop diabetes at 3 mo of age and progressive proteinuria and diabetic nephropathy as they age from 6 to 18 mo. Plasma creatinine levels after bilateral IR were significantly higher (3.4 ± 0.1 mg/dl) in 18-mo-old elderly T2DN rats than in middle-aged (12 mo) T2DN rats with less severe diabetic nephropathy or young (3 mo) and elderly (18 mo) control SD rats (1.5 ± 0.2, 1.8 ± 0.1, and 1.7 ± 0.1 mg/dl, respectively). Elderly T2DN rats exhibited a greater fall in medullary blood flow 2 h following renal IR and a more severe and prolonged decline in glomerular filtration rate than middle-aged T2DN and young or elderly SD rats. The basal expression of the adhesion molecules ICAM-1 and E-selectin and the number of infiltrating immune cells was higher in the kidney of elderly T2DN than age-matched SD rats or young and middle-aged T2DN rats before renal IR. These results indicate that elderly T2DN rats with diabetic nephropathy are more susceptible to renal IR injury than diabetic animals with mild injury or age-matched control animals. This is associated with increased expression of ICAM-1, E-selectin and immune cell infiltration, renal medullary vasocongestion, and more prolonged renal medullary ischemia.

Impact of Acute Kidney Injury and CKD on Adverse Outcomes in Critically Ill Septic Patients

Introduction

Chronic kidney disease (CKD) and acute kidney injury (AKI) are strongly associated with excess morbidity and mortality and frequently co-occur in critically ill septic patients, but how their interplay affects clinical outcomes is not well elucidated.

Methods

We conducted a single-center, retrospective cohort study of 2632 adult patients admitted to the intensive care unit (ICU) with severe sepsis or septic shock. Subjects were classified into 6 groups according to baseline CKD (no-CKD: estimated glomerular filtration rate [eGFR] ≥60; CKD: eGFR 15−59 ml/min per 1.73 m²) and incident AKI by the Kidney Disease: Improving Global Outcomes (KDIGO) serum creatinine criteria (no-AKI, AKI stage 1, AKI stages ≥2) during ICU stay. Study outcomes were 90-day mortality (in hospital or within 90 days of discharge) and incident/progressive CKD.

Results

Prevalent CKD was 46% and incident AKI was 57%. Adjusted hazard ratios (95% confidence intervals) for 90-day mortality relative to the reference group of no-CKD/no-AKI were 1.5 (1.1−2.0) in no-CKD/AKI stage 1, 2.4 (1.9−3.1) in no-CKD/AKI stages≥2, 1.1 (0.8−1.4) in CKD/no-AKI, 1.2 (0.9−1.6) in CKD/AKI stage 1, and 2.2 (1.7−2.9) in CKD/AKI stages ≥2. A similar trend was observed for incident/progressive CKD during a median follow-up of 15.3 months.

Conclusion

Stage 1 AKI on CKD was not associated with an independent increased risk of adverse outcomes in critically ill septic patients. AKI stages ≥2 on CKD and any level of AKI in no-CKD patients were strongly and independently associated with adverse outcomes. Sepsis-associated stage 1 AKI on CKD may represent distinct underlying pathophysiology, with more prerenal cases and less severe de novo intrinsic damage, which needs further investigation.

The Impact of Preexisting Chronic Kidney Disease on the Severity and Recovery of Acute Kidney Injury

BACKGROUND

Recent observational studies have shown that in chronic kidney disease (CKD) patients, a significantly smaller percentage of patients with an episode of acute kidney injury (AKI) have full recovery of renal function compared to those without CKD. However, precise mechanisms involved in the incomplete repair after AKI with preexisting CKD have not been completely ascertained. Here, we assessed the impact of preexisting CKD on the severity and recovery of AKI in a mouse model of 5/6 nephrectomy.

METHODS

Male CD-1 mice underwent 5/6 nephrectomy (Nx). Six weeks post surgery, ischemia reperfusion injury (IRI) or a sham operation was performed and functional, histological, and various molecular parameters were compared between them.

RESULTS

Serum creatinine level on day 1 after IRI was comparable between control and Nx mice. However, serum creatinine remained significantly higher throughout the recovery phase in Nx mice compared to control mice. mRNA and protein expression of the cell cycle regulatory proteins were persistently elevated in Nx mice and this was associated with significantly increased levels of the G1 cell cycle arrest markers. Treatment with a p53 inhibitor following IRI resulted in not only decreased expression of G1 arrest markers but also decreased fibrosis, suggesting that prolonged epithelial G1 cell cycle arrest might be partially responsible for impaired recovery from superimposed AKI on CKD.

CONCLUSION

Taken together, reduced nephron mass have a negative effect on the repair process that is partially mediated by the disruption of the cell cycle regulation.

Association of hyperglycemic crisis with an increased risk of end-stage renal disease: A nationwide population-based cohort study

BACKGROUND

A hyperglycemic crisis episode (HCE) is associated with poor management of diabetes, which is a risk factor for end-stage renal disease (ESRD); however, the association between an HCE and ESRD has not been clarified. We conducted a nationwide population-based cohort study with the purpose of delineating this issue.

METHODS

We identified 9208 diabetic patients with an HCE and an identical number of diabetic patients with matched age, sex, and index date without an HCE between 2000 and 2002. A comparison of the risk of ESRD between the diabetic patients with and without an HCE was achieved by a follow-up until 2014.

RESULTS

A Cox proportional hazard regression analysis showed that the diabetic patients with an HCE were at a higher risk of ESRD than those without an HCE (the adjusted hazard ratio [AHR]: 1.47; 95% confidence interval [CI]: 1.34-1.62) by adjusting for renal disease, hypertension, hyperlipidemia, coronary artery disease, hyperuricemia, anemia, chronic obstructive pulmonary disease, liver disease, malignancy, connective tissue disease, non-steroid anti-inflammatory drug use, and monthly income. The increased risk of ESRD was more prominent in the age subgroup of 15-25 years (AHR: 4.91; 95% CI: 1.92-12.56); 25-35 years (AHR: 2.42; 95% CI: 1.51-3.86); 35-45 years (AHR: 3.01; 95% CI: 2.21-4.09); and 45-55 years (AHR: 1.75; 95% CI: 1.41-2.19).

CONCLUSIONS

An HCE was associated with an increased risk of ESRD, especially in the younger diabetic patients (15-55 years). A close follow-up for the control of diabetes and for monitoring renal function is proposed.

Characteristics of and risk factors for death in elderly patients with acute kidney injury: a multicentre retrospective study in China

Purpose of the study

The incidence of acute kidney injury (AKI) with a poor prognosis in the elderly has been increasing each year. This study aimed to investigate the clinical characteristics of and risk factors for death from AKI in the elderly and help improve prognosis.

Study design

This study was a retrospective cohort study based on data from adult patients (≥18 years old) admitted to 15 hospitals in China between 1 January 2009 and 31 December 2011. The characteristics of AKI in the elderly were compared with those in younger patients.

Results

In elderly patients with AKI, rates of hypertension, cardiovascular disease and multiple organ dysfunction syndrome (MODS) were higher than in younger patients (44.2% vs 31.2%, 16.1% vs 4.6% and 20.9% vs 16.9%, respectively), the length of ICU stay was longer (3.8 days vs 2.7 days, P=0.019) and renal biopsy (1.0% vs 7.13%, P<0.001) and dialysis (9.6% vs 19.2%, P<0.001) were performed less. Hospital-acquired (HA) AKI was more common than community-acquired (CA) AKI (60.3% vs 39.7%), while the most common cause of AKI was pre-renal (53.5%). Multiple logistic regression analysis showed that age (OR 1.041, 95% CI 1.023 to 1.059), cardiovascular disease (OR 1.980, 95% CI 1.402 to 2.797), cancer (OR 2.302, 95% CI 1.654 to 3.203), MODS (OR 3.023, 95% CI 1.627 to 5.620) and mechanical ventilation (OR 2.408, 95% CI 1.187 to 4.887) were significant risk factors for death.

Conclusions

HA-AKI and pre-renal AKI were more common in the elderly. Age, cardiovascular disease, cancer, MODS and mechanical ventilation were independent risk factors for death in the elderly with AKI.

Risk for acute kidney injury in primary health care

ABSTRACT Objective: To identify hypertensive and diabetic patients at risk for developing acute kidney injury in the primary health care setting. Method: Observational, longitudinal, prospective study. Sample of 56 diabetic and hypertensive individuals. A semi-structured questionnaire was adopted for data collection. For the description of results, were calculated dispersion measures and the Spearman test was used for statistical analysis. The result was considered significant when p <0.05. Results: Of the total sample, 23.2% of users evolved with renal impairment, of which 19.6% with risk for renal injury, and 3.6% with kidney injury itself. Age and body mass index were associated with worsening of renal function (p = 0.0001; p = 0.0003), respectively. Conclusion: A quarter of the health system users, hypertensive and diabetic, evolved with impaired renal function, more specifically to stages of risk for renal injury and kidney injury according to the RIFLE classification.

Acute kidney injury among adult patients undergoing major surgery in a tertiary hospital in Nigeria

Background

Acute kidney injury (AKI) is an underreported but major cause of morbidity and mortality among patients undergoing major surgical interventions in sub-Saharan Africa (SSA). Whereas AKI is often seen following major cardiac surgery in high-income countries, a similar spectrum of surgical diseases and interventions is not seen in developing countries. The impacts on surgical outcomes have also not been well characterized in SSA. This study aimed at identifying risk factors, incidence and determinants and short-term outcomes of AKI among patients undergoing major surgery.

Methods

This was a cohort study of adult patients undergoing major surgery at the University College Hospital, Ibadan, Nigeria. Data obtained were sociodemographic details, risk factors for AKI, details of surgery, anaesthesia and intra-operative events and short-term outcomes. Blood samples were obtained for pre-operative (pre-op) full blood count, serum electrolytes, blood urea and creatinine (SCr). Post-operatively (Post-op) SCr was determined at 24 h, Day 7 post-op and weekly until each patient was discharged.

Results

A total of 219 subjects who had major surgery (86.3% elective) were enrolled. The median age of the patients was 46 (range 18-73) years and 72.6% were females. The surgeries performed were mostly simple mastectomies (37.4%), exploratory laparotomies (22.8%) and total thyroidectomies (16.4%). The incidences of AKI were 18.7% at 24 h and 17.4% at Day 7 post-op, while cumulative AKI incidence was 22.5% at 1-week post-op. Pre-op elevated SCr [odds ratio (OR) 3.86], sepsis (OR 2.69), anaemia (OR 2.91) and duration of surgery >120 min (OR 1.75) were independently associated with AKI. In-patient mortality was 20.4% in individuals with AKI and 5.3% in those without AKI (P < 0.01).

Conclusion

Peri-operative risk factors for AKI are common among patients undergoing major surgery in SSA hospitals. The cumulative incidence of AKI was high and independently associated with pre-op sepsis, anaemia, pre-existing kidney dysfunction and duration of surgery >120 min.

Predictors of Perioperative Acute Kidney Injury in Obese Patients Undergoing Laparoscopic Bariatric Surgery: a Single-Centre Retrospective Cohort Study

BACKGROUND

Obesity has been associated with increased risk of perioperative acute kidney injury (AKI). We aim to establish the incidence of AKI among patients undergoing laparoscopic bariatric surgery and identify potential risk factors.

METHODS

Records of 1230 patients who underwent laparoscopic bariatric surgery in a tertiary centre from 1 December 2009 to 31 January 2014 were retrospectively studied. AKI diagnosis was made by comparing the baseline and post-operative serum creatinine to determine the presence of predefined significant change based on the Kidney Disease: Improving Global Outcomes (KDIGO) definition. Univariate analyses were performed to determine significant clinical factors, and multiple logistic regression analysis was subsequently done to determine independent predictors of AKI.

RESULTS

Thirty-five (2.9 %) patients developed AKI during the first 72 h post-surgery. Multivariate logistic regression analysis revealed impaired renal function (OR 10.429, 95 % CI 3.560 to 30.552), use of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers (OR 3.038, 95 % CI 1.352 to 6.824), and body mass index (OR 1.048, 95 % CI 1.005 to 1.093) as independent predictors of perioperative acute kidney injury in the obese patients who underwent laparoscopic bariatric surgery.

CONCLUSIONS

We found that the incidence of perioperative AKI among patients who underwent laparoscopic bariatric surgery is at 2.9 %. Impaired renal function, use of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers and raised body mass index were found to be independent predictors of AKI. Patients with these risk factors could be considered at risk for developing perioperative AKI, and extra perioperative vigilance should be undertaken.

PATTERNS OF HEALTHCARE ENCOUNTERS EXPERIENCED BY PATIENTS WITH CHRONIC KIDNEY DISEASE

BACKGROUND

Patterns of healthcare encounters by patients in each stage of chronic kidney disease (CKD) have not been fully described.

OBJECTIVE

This study describes patterns of healthcare resource use by patients with CKD.

DESIGN

A retrospective descriptive design was used.

PARTICIPANTS

Patients with Stages 1-5 CKD were identified in five existing de-identified healthcare insurance claims databases in the United States using codes from the International Classification of Diseases (ICD-9-CM).

MEASUREMENTS

The databases contained more than 23,660,000 claims records from over 11 million subscribers who were continuously enrolled in a single 2014 health plan. All CKD patients' 2014 claims were extracted, yielding 1,987 unique people with 110,594 healthcare encounters.

RESULTS

Healthcare resources are used to manage the causes of CKD and its multiple effects on health, and thus the number of healthcare encounters among people with more advanced disease was, as expected, relatively higher. There were more hospitalisations, emergency department visits and specialist encounters in this group. Surprisingly, however, even people in earlier stages of kidney disease experienced a median of 14-17 healthcare encounters during a single calendar year.

CONCLUSIONS

Understanding patterns of healthcare encounters provides important information about the transition experiences of patients with CKD. Exploring ways to reduce the risks associated with transitions in care may prevent problems with home medication management, frequent emergency department visits and potentially avoidable hospitalisations.

Long-term kidney outcomes among users of proton pump inhibitors without intervening acute kidney injury

Proton pump inhibitor (PPI) use is associated with an increased risk of acute kidney injury (AKI), incident chronic kidney disease (CKD), and progression to end-stage renal disease (ESRD). PPI-associated CKD is presumed to be mediated by intervening AKI. However, whether PPI use is associated with an increased risk of chronic renal outcomes in the absence of intervening AKI is unknown. To evaluate this we used the Department of Veterans Affairs national databases to build a cohort of 144,032 incident users of acid suppression therapy that included 125,596 PPI and 18,436 Histamine H2 receptor antagonist (H2 blockers) consumers. Over 5 years of follow-up in survival models, cohort participants were censored at the time of AKI occurrence. Compared with incident users of H2 blockers, incident users of PPIs had an increased risk of an estimated glomerular filtration rate (eGFR) under 60 ml/min/1.73m² (hazard ratio 1.19; 95% confidence interval 1.15-1.24), incident CKD (1.26; 1.20-1.33), eGFR decline over 30% (1.22; 1.16-1.28), and ESRD or eGFR decline over 50% (1.30; 1.15-1.48). Results were consistent in models that excluded participants with AKI either before chronic renal outcomes, during the time in the cohort, or before cohort entry. The proportion of PPI effect mediated by AKI was 44.7%, 45.47%, 46.00%, and 46.72% for incident eGFR under 60 ml/min/1.73m², incident CKD, eGFR decline over 30%, and ESRD or over 50% decline in eGFR, respectively. Thus, PPI use is associated with increased risk of chronic renal outcomes in the absence of intervening AKI. Hence, reliance on antecedent AKI as warning sign to guard against the risk of CKD among PPI users is not sufficient as a sole mitigation strategy.

The Role of Acute Kidney Injury in Chronic Kidney Disease

There is increasing recognition that acute kidney injury (AKI) and chronic kidney disease (CKD) are closely linked and likely promote one another. Underlying CKD now is recognized as a clear risk factor for AKI because both decreased glomerular filtration rate and increased proteinuria have been shown to be associated strongly with AKI. A growing body of literature also provides evidence that AKI accelerates the progression of CKD. Individuals who suffered dialysis-requiring AKI are particularly vulnerable to worse long-term renal outcomes, including end-stage renal disease. The association between AKI and subsequent renal function decline is amplified by pre-existing severity of CKD, higher stage of AKI, and the cumulative number of AKI episodes. However, residual confounding and ascertainment bias may partly explain the epidemiologic association between AKI and CKD in observational studies. As the number of AKI survivors increases, we need to better understand other clinically important outcomes after AKI, identify those at highest risk for the most adverse sequelae, and develop strategies to optimize their care.

Development of risk models for the prediction of new or worsening acute kidney injury on or during hospital admission: a cohort and nested study

Background

Acute kidney injury (AKI) is a common clinical problem with significant morbidity and mortality. All hospitalised patients are at risk. AKI is often preventable and reversible; however, the 2009 National Confidential Enquiry into Patient Outcome and Death highlighted systematic failings of identification and management, and recommended risk assessment of all emergency admissions.

Objectives

To develop three predictive models to stratify the risk of (1) AKI on arrival in hospital; (2) developing AKI during admission; and (3) worsening AKI if already present; and also to (4) develop a clinical algorithm for patients admitted to hospital and explore effective methods of delivery of this information at the point of care.

Study design

Quantitative methodology (1) to formulate predictive risk models and (2) to validate the models in both our population and a second population. Qualitative methodology to plan clinical decision support system (CDSS) development and effective integration into clinical care.

Settings and participants

Quantitative analysis – the study population comprised hospital admissions to three acute hospitals of East Kent Hospitals University NHS Foundation Trust in 2011, excluding maternity and elective admissions. For validation in a second population the study included hospital admissions to Medway NHS Foundation Trust. Qualitative analysis – the sample consisted of six renal consultants (interviews) and six outreach nurses (focus group), with representation from all sites.

Data collection

Data (comprising age, sex, comorbidities, hospital admission and outpatient history, relevant pathology tests, drug history, baseline creatinine and chronic kidney disease stage, proteinuria, operative procedures and microbiology) were collected from the hospital data warehouse and the pathology and surgical procedure databases.

Data analysis

Quantitative – both traditional and Bayesian regression methods were used. Traditional methods were performed using ordinal logistic regression with univariable analyses to inform the development of multivariable analyses. Backwards selection was used to retain only statistically significant variables in the final models. The models were validated using actual and predicted probabilities, an area under the receiver operating characteristic (AUROC) curve analysis and the Hosmer–Lemeshow test. Qualitative – content analysis was employed.

Main outcome measures

(1) A clinical pratice algorithm to guide clinical alerting and risk modeling for AKI in emergency hospital admissions; (2) identification of the key variables that are associated with the risk of AKI; (3) validated risk models for AKI in acute hospital admissions; and (4) a qualitative analysis providing guidance as to the best approach to the implementation of clinical alerting to highlight patients at risk of AKI in hospitals.

Findings

Quantitative – we have defined a clinical practice algorithm for risk assessment within the first 24 hours of hospital admission. Bayesian methodology enabled prediction of low risk but could not reliably identify high-risk patients. Traditional methods identified key variables, which predict AKI both on admission and at 72 hours post admission. Validation demonstrated an AUROC curve of 0.75 and 0.68, respectively. Predicting worsening AKI during admission was unsuccessful. Qualitative – analysis of AKI alerting gave valuable insights in terms of user friendliness, information availability, clinical communication and clinical responsibility, and has informed CDSS development.

Conclusions

This study provides valuable evidence of relationships between key variables and AKI. We have developed a clinical algorithm and risk models for risk assessment within the first 24 hours of hospital admission. However, the study has its limitations, and further analysis and testing, including continuous modelling, non-linear modelling and interaction exploration, may further refine the models. The qualitative study has highlighted the complexity regarding the implementation and delivery of alerting systems in clinical practice.

Funding

The National Institute for Health Research Health Services and Delivery Research programme.

Urinary Kininogen-1 and Retinol binding protein-4 respond to Acute Kidney Injury: predictors of patient prognosis?

Implementation of therapy for acute kidney injury (AKI) depends on successful prediction of individual patient prognosis. Clinical markers as serum creatinine (sCr) have limitations in sensitivity and early response. The aim of the study was to identify novel molecules in urine which show altered levels in response to AKI and investigate their value as predictors of recovery. Changes in the urinary proteome were here investigated in a cohort of 88 subjects (55 AKI patients and 33 healthy donors) grouped in discovery and validation independent cohorts. Patients’ urine was collected at three time points: within the first 48 h after diagnosis(T1), at 7 days of follow-up(T2) and at discharge of Nephrology(T3). Differential gel electrophoresis was performed and data were confirmed by Western blot (WB), liquid chromatography/mass spectrometry (LC-MS/MS) and enzyme-linked immunosorbent assay (ELISA). Retinol binding protein 4 (RBP4) and kininogen-1 (KNG1) were found significantly altered following AKI. RBP4 increased at T1, and progressively decreased towards normalization. Maintained decrease was observed for KNG1 from T1. Individual patient response along time revealed RBP4 responds to recovery earlier than sCr. In conclusion, KNG1 and RBP4 respond to AKI. By monitoring RBP4, patient’s recovery can be anticipated pointing to a role of RBP4 in prognosis evaluation.

Transcatheter Aortic Valve Replacement: a Kidney's Perspective

Transcatheter aortic valve replacement (TAVR) has now emerged as a viable treatment option for high-risk patients with severe aortic stenosis (AS) who are not suitable candidates for surgical aortic valve replacement (SAVR). Despite encouraging published outcomes, acute kidney injury (AKI) is common and lowers the survival of patients after TAVR. The pathogenesis of AKI after TAVR is multifactorial including TAVR specific factors such as the use of contrast agents, hypotension during rapid pacing, and embolization; preventive measures may include pre-procedural hydration, limitation of contrast dye exposure, and avoidance of intraprocedural hypotension. In recent years, the number of TAVR performed worldwide has been increasing, as well as published data on renal perspectives of TAVR including AKI, chronic kidney disease, end-stage kidney disease, and kidney transplantation. This review aims to present the current literature on the nephrology aspects of TAVR, ultimately to improve the patients' quality of care and outcomes.