A New Criterion for Pediatric AKI Based on the Reference Change Value of Serum Creatinine

Construction of a machine learning-based prediction model for unfavorable discharge outcomes in patients with ischemic stroke

Background

Ischemic stroke is a common and serious disease with economic and healthcare burdens. Predicting the unfavorable discharge outcome of patients is essential for formulating appropriate treatment strategies and providing personalized care. Therefore, this study aims to establish and validate a prediction model based on machine learning methods to accurately predict the discharge outcome of ischemic stroke patients, providing valuable information for clinical decision making.

Methods

The derivation data consisted of 964 patients from Guangdong Provincial People's Hospital and was used for training and internal validation. A favourable discharge outcome was defined as a National Institutes of Health Stroke Scale score of ≤1 or a decrease of ≥8 points compared to the admission score. A predictive model was created based on 88 medical characteristics gathered during the patient's initial admission, using nine machine learning algorithms. The model's predictive performance was compared using various evaluation metrics. The final model's feature importance was ranked and explained using the Shapley additive explanation method.

Findings

The random forest model demonstrated the greatest discriminative ability among the nine machine learning models. We created an interpretable random forest model by ranking and reducing the features based on their importance, which included eight features. In internal validations, the final model accurately predicted the discharge outcomes of ischemic stroke with AUC values of 0.903 and has been translated into a convenient tool to facilitate its utility in clinical settings.

Conclusions

Our explainable ML model was not only successfully developed to accurately predict discharge outcomes in patients with ischemic stroke and it mitigated the concern of the "black-box" issue with an undirect interpretation of the ML technique.

Prognostic value of systemic inflammatory response index for acute kidney injury and the prognosis of pediatric patients in critical care units

BACKGROUND

We proposed a link between the first systemic inflammatory response index (SIRI) and acute kidney injury (AKI), as well as the prognosis of pediatric patients in intensive care units (PICU).

METHODS

This study comprised 5114 children from the pediatric-specific intensive care (PIC) database. SIRI was estimated as a neutrophil monocyte lymphocyte ratio. All patients were arbitrarily allocated to the training set (n = 3593) and the validation cohort (n = 1521) and divided into two groups depending on their SIRI levels. The diagnostic value of SIRI for pediatric ICU patients was subsequently determined using LASSO regression models.

RESULTS

After controlling for additional confounding variables in the training set, the higher SIRI value (≥ 0.59) had a greater risk of AKI (adjusted odds ratio, OR, 3.95, 95% confidence interval, 95%CI, 2.91-5.36, P<0.001) and in-hospital mortality (hazard ratio, HR, 5.01, 95%CI 2.09-12.03, P<0.001). Similar findings were discovered in the validation set. Furthermore, the suggested nomogram derived from SIRI and other clinical metrics showed outstanding calibration capability as well as therapeutic usefulness in both groups.

CONCLUSIONS

SIRI is a reliable and useful factor for AKI and fatality in pediatric ICU patients, and the proposed nomogram based on SIRI yields an appropriate prediction value for critically sick pediatric patients.

Acute kidney injury in children undergoing cardiac surgery: predictive value of kidney arterial Doppler-based variables

BACKGROUND

Acute kidney injury (AKI) is a common condition in critically ill children and is associated with increased morbidity and mortality. This study aimed to assess the performance of point-of-care ultrasonography to predict AKI in children undergoing cardiac surgery.

METHODS

In this prospective study, consecutive children underwent kidney Doppler ultrasound examination within 24 h following cardiac surgery, and an experienced operator obtained both renal resistive index (RRI) and renal pulsatility index (RPI). AKI was defined by the Kidney Disease Improving Global Outcome (KDIGO) criteria. The primary outcome was the diagnosis of severe AKI (KDIGO stage 2 or 3) on day 3.

RESULTS

A total of 58 patients were included. Median age and weight were 12.9 months (IQR 6.0-37.9) and 7.36 kg (IQR 5.19-11.40), respectively. On day 3, 13 patients were classified as having AKI, of which 11 were severe. RRI could effectively predict AKI (area under the ROC curve [AUC] 0.83, 95% CI 0.71-0.92; p < 0.001) as well as RPI (AUC 0.81, 95% CI 0.69-0.90; p < 0.001). The optimal cutoff value for RRI was 0.85 (sensitivity, 73%; specificity, 83%; positive predictive value [PPV], 50%; and negative predictive value [NPV], 93%), while for RPI was 1.95 (sensitivity, 73%; specificity, 78%; PPV, 44%; and NPV, 92%). Similar results were found in the analysis for prediction on day 5. Significant correlations were found between Doppler-based variables and estimated GFR and furosemide dose on day 3.

CONCLUSIONS

Kidney Doppler ultrasound may be a promising tool for predicting AKI in children undergoing cardiac surgery.

Acute Kidney Injury in Neonatal Intensive Care Unit: Epidemiology, Diagnosis and Risk Factors

Acute kidney injury (AKI) is associated with long-term consequences and poor outcomes in the neonatal intensive care unit. Its precocious diagnosis represents one of the hardest challenges in clinical practice due to the lack of sensitive and specific biomarkers. Currently, neonatal AKI is defined with urinary markers and serum creatinine (sCr), with limitations in early detection and individual treatment. Biomarkers and risk factor scores were studied to predict neonatal AKI, to early identify the stage of injury and not the damage and to anticipate late increases in sCr levels, which occurred when the renal function already began to decline. Sepsis is the leading cause of AKI, and sepsis-related AKI is one of the main causes of high mortality. Moreover, preterm neonates, as well as patients with post-neonatal asphyxia or after cardiac surgery, are at a high risk for AKI. Critical patients are frequently exposed to nephrotoxic medications, representing a potentially preventable cause of AKI. This review highlights the definition of neonatal AKI, its diagnosis and new biomarkers available in clinical practice and in the near future. We analyze the risk factors involving patients with AKI, their outcomes and the risk for the transition from acute damage to chronic kidney disease.

Biomarkers vs Machines: The Race to Predict Acute Kidney Injury

BACKGROUND

Acute kidney injury (AKI) is a serious complication affecting up to 15% of hospitalized patients. Early diagnosis is critical to prevent irreversible kidney damage that could otherwise lead to significant morbidity and mortality. However, AKI is a clinically silent syndrome, and current detection primarily relies on measuring a rise in serum creatinine, an imperfect marker that can be slow to react to developing AKI. Over the past decade, new innovations have emerged in the form of biomarkers and artificial intelligence tools to aid in the early diagnosis and prediction of imminent AKI.

CONTENT

This review summarizes and critically evaluates the latest developments in AKI detection and prediction by emerging biomarkers and artificial intelligence. Main guidelines and studies discussed herein include those evaluating clinical utilitiy of alternate filtration markers such as cystatin C and structural injury markers such as neutrophil gelatinase-associated lipocalin and tissue inhibitor of metalloprotease 2 with insulin-like growth factor binding protein 7 and machine learning algorithms for the detection and prediction of AKI in adult and pediatric populations. Recommendations for clinical practices considering the adoption of these new tools are also provided.

SUMMARY

The race to detect AKI is heating up. Regulatory approval of select biomarkers for clinical use and the emergence of machine learning algorithms that can predict imminent AKI with high accuracy are all promising developments. But the race is far from being won. Future research focusing on clinical outcome studies that demonstrate the utility and validity of implementing these new tools into clinical practice is needed.

Sex bias in prediction and diagnosis of cardiac surgery associated acute kidney injury

BACKGROUND

Female sex has been recognized as a risk factor for cardiac surgery associated acute kidney injury (CS-AKI). The current study sought to evaluate whether female sex is a risk factor for CS-AKI, or modifies the association of peri-operative change in serum creatinine with CS-AKI.

METHODS

Observational study of adult patients undergoing cardiac surgery between 2000 and 2019 in a single U.S. center. The main variable of interest was registered patient sex, identified from electronic medical records. The main outcome was CS-AKI within 2 weeks of surgery.

RESULTS

Of 58526 patients, 19353 (33%) were female; 12934 (22%) incurred AKI based on ≥ 0.3 mg/dL or ≥ 50% rise in serum creatinine (any AKI), 3320 (5.7%) had moderate to severe AKI, and 1018 (1.7%) required dialysis within 2 weeks of surgery. Female sex was associated with higher risk for AKI in models that were based on preoperative serum creatinine (OR, 1.35; 95% CI, 1.29-1.42), and lower risk with the use of estimated glomerular filtration, (OR, 0.90; 95% CI, 0.86-0.95). The risk for moderate to severe CS-AKI for a given immediate peri-operative change in serum creatinine was higher in female compared to male patients (p < .0001 and p < .0001 for non-linearity), and the association was modified by pre-operative kidney function (p < .0001 for interaction).

CONCLUSIONS

The association of patient sex with CS-AKI and its direction was dependent on the operational definition of pre-operative kidney function, and differential outcome misclassification due to AKI defined by absolute change in serum creatinine.

Renal angina index for early identification of risk of acute kidney injury in critically ill children

BACKGROUND

The main objective was to test whether the Renal Angina Index (RAI), calculated on patient admission to the pediatric intensive care unit (PICU), is associated with the risk of acute kidney injury (AKI) based on the Kidney Disease: Improving Global Outcomes (KDIGO) (stage ≥ 2) in 72 h. The specific aim was to analyze the performance of the RAI at a specialized oncology PICU.

METHODS

Retrospective cohort study involving two pediatric intensive care units located within a general hospital and an oncology hospital. Children aged ≥ 3 months to < 18 years admitted to the intensive care units in 2017 with a length of stay ≥ 72 h were included.

RESULTS

The sample included 249 patients, of which 51% were male (127 patients), with median age of 77 months, and mean ICU stay of 5 days. Of the total admissions, 141 were clinical (57%) and 108 surgical. The rate of AKI was 15% and death rate within 30 days was 13%. Having a positive RAI on admission showed a statistically significant association with AKI at Day 3 (OR = 18.5, 95%CI = 4.3 - 78.9, p < 0.001) and with death (OR = 3.9, 95%CI = 1.6 - 9.9, p = 0.004). The accuracy of the RAI in the cancer population was 0.81 on the ROC curve (95%CI 0.74, 0.88).

CONCLUSIONS

The RAI is a useful tool for predicting AKI and death in critically ill children, including in oncology units.

Comparison of diagnostic criteria for sepsis-associated acute kidney injury in the pediatric intensive care unit: a retrospective cohort study

Background

pRIFLE (Pediatric Risk, Injury, Failure, Loss, End Stage Renal Disease), KDIGO (Kidney Disease Improving Global Outcomes) and pROCK (Pediatric Reference Change Value Optimized for AKI) are diagnostic criteria used for acute kidney injury (AKI) incidence evaluation. The aim of this study was to explore the diagnostic consistency, incidence and mortality rate, clinical signs, and influencing factors of renal injury related to sepsis in children diagnosed by three different AKI diagnostic criteria, and then evaluate which one was more valuable.

Methods

A retrospective analysis was performed on the clinical data of children with severe sepsis. The patients were diagnosed and staged according to the 2007 pRIFLE standard, the 2012 KDIGO standard, and the 2018 pROCK standard. The clinical characteristics and prognosis of children with different stages of sepsis were compared between the three diagnostic standards.

Results

A total of 62 patients with sepsis were included. Blood stream infection is common (11 cases, 17.74%). According to pRIFLE, KDIGO, and pROCK standards, the incidence of sepsis-associated AKI (SA-AKI) was 74.2%, 67.7%, and 56.5%, respectively. The pRIFLE had the highest diagnostic rate of early detection of SA-AKI. There was no statistical difference in SA-AKI incidence or staging consistency between the pRIFLE and KDIGO groups (κ=0.0671; κ>0.60); the consistency of SA-AKI diagnoses across the three standards was good (all P values <0.05), and pROCK demonstrated a higher specificity. A high Pediatric Risk of Mortality (PRISM) score and high procalcitonin level were independent risk factors. Shock and renal replacement therapy were independent risk factors for SA-AKI death. Death from admission to 28 days after admission was used as an endpoint to draw a survival graph, which revealed that the AKI group had a significantly higher risk of death than did the non-AKI group.

Conclusions

The consistency of diagnosing SA-AKI across the three classification criteria was similar, and mortality rate increased with increased SA-AKI staging. The pRIFLE criteria were more sensitive in the early detection of SA-AKI, while the pROCK had higher specificity. There was no significant difference between the pRIFLE and KDIGO in terms of incidence, diagnosis, or staging of SA-AKI.

Sex Bias in Prediction and Diagnosis of Cardiac Surgery Associated Acute Kidney Injury

Background

Female sex has been recognized as a risk factor for cardiac surgery associated acute kidney injury (CS-AKI). The current study sought to evaluate whether female sex is a risk factor for CS-AKI, or modifies the association of peri-operative change in serum creatinine with CS-AKI.

Methods

Observational study of adult patients undergoing cardiac surgery between 2000 and 2019 in a single U.S. center. The main variable of interest was registered patient sex, identified from electronic medical records. The main outcome was CS-AKI within 2 weeks of surgery.

Results

Of 58526 patients, 19353 (33%) were female; 12934 (22%) incurred AKI based on ≥ 0.3 mg/dL or ≥ 50% rise in serum creatinine (any AKI), 3320 (5.7%) had moderate to severe AKI, and 1018 (1.7%) required dialysis within 2 weeks of surgery. Female sex was associated with higher risk for AKI in models that were based on preoperative serum creatinine (OR, 1.35; 95% CI, 1.29-1.42), and lower risk with the use of estimated glomerular filtration, (OR, 0.90; 95% CI, 0.86-0.95). The risk for moderate to severe CS-AKI for a given immediate peri-operative change in serum creatinine was higher in female compared to male patients (p < .0001 and p < .0001 for non-linearity), and the association was modified by pre-operative kidney function (p < .0001 for interaction).

Conclusions

The association of patient sex with CS-AKI and its direction was dependent on the operational definition of pre-operative kidney function, and differential outcome misclassification due to AKI defined by absolute change in serum creatinine.

Identification and validation of an explainable prediction model of acute kidney injury with prognostic implications in critically ill children: a prospective multicenter cohort study

Background

Acute kidney injury (AKI) is a common and serious organ dysfunction in critically ill children. Early identification and prediction of AKI are of great significance. However, current AKI criteria are insufficiently sensitive and specific, and AKI heterogeneity limits the clinical value of AKI biomarkers. This study aimed to establish and validate an explainable prediction model based on the machine learning (ML) approach for AKI, and assess its prognostic implications in children admitted to the pediatric intensive care unit (PICU).

Methods

This multicenter prospective study in China was conducted on critically ill children for the derivation and validation of the prediction model. The derivation cohort, consisting of 957 children admitted to four independent PICUs from September 2020 to January 2021, was separated for training and internal validation, and an external data set of 866 children admitted from February 2021 to February 2022 was employed for external validation. AKI was defined based on serum creatinine and urine output using the Kidney Disease: Improving Global Outcome (KDIGO) criteria. With 33 medical characteristics easily obtained or evaluated during the first 24 h after PICU admission, 11 ML algorithms were used to construct prediction models. Several evaluation indexes, including the area under the receiver-operating-characteristic curve (AUC), were used to compare the predictive performance. The SHapley Additive exPlanation method was used to rank the feature importance and explain the final model. A probability threshold for the final model was identified for AKI prediction and subgrouping. Clinical outcomes were evaluated in various subgroups determined by a combination of the final model and KDIGO criteria.

Findings

The random forest (RF) model performed best in discriminative ability among the 11 ML models. After reducing features according to feature importance rank, an explainable final RF model was established with 8 features. The final model could accurately predict AKI in both internal (AUC = 0.929) and external (AUC = 0.910) validations, and has been translated into a convenient tool to facilitate its utility in clinical settings. Critically ill children with a probability exceeding or equal to the threshold in the final model had a higher risk of death and multiple organ dysfunctions, regardless of whether they met the KDIGO criteria for AKI.

Interpretation

Our explainable ML model was not only successfully developed to accurately predict AKI but was also highly relevant to adverse outcomes in individual children at an early stage of PICU admission, and it mitigated the concern of the "black-box" issue with an undirect interpretation of the ML technique.

Funding

The National Natural Science Foundation of China, Jiangsu Province Science and Technology Support Program, Key talent of women's and children's health of Jiangsu Province, and Postgraduate Research & Practice Innovation Program of Jiangsu Province.

A new criteria for acute on preexisting kidney dysfunction in critically ill patients

Critically ill patients with preexisting kidney dysfunction (PKD) are at high risk for acute kidney injury (AKI). Nevertheless, there is no criteria for screening and classifying AKI in patients with PKD. In this study, after assessing relationship between the change in SCr from baseline and in-hospital mortality, a new criteria, named APKD, for identifying AKI in PKD was proposed. APKD defined AKI in critically ill patients with PKD as an absolute increase of ≥ 0.2 mg/dL in SCr within 48 h or an increase in SCr ≥ 1.1 times over baseline within 7 d. APKD detected more AKI among PKD patients compared with the other criteria. Additionally, the AKI patients identified by APKD but missed by the other criteria had higher mortality than those without AKI. APKD shows higher sensitivities than KDIGO criteria in predicating in-hospital mortality. APKD, but not the KDIGO, is effective for staging the severity of AKI in patients with PKD. In conclusion, APKD is more effective in screening and classifying AKI in critically ill patients with PKD compared with the earlier criteria, and it may helpful in guiding clinical treatment and predicting prognosis.

Efficacy and safety of multi-target therapy in children with lupus nephritis

BACKGROUND

To analyze the efficacy and safety of multi-target therapy in children with lupus nephritis (LN).

METHODS

In our retrospective study from January 2009 to December 2021, the multi-target therapy of glucocorticoids, MMF and tacrolimus was adopted as induction therapy or re-induction therapy for 36 LN children who had combined proliferative and membranous LN or for who were ineffective to combination therapy of glucocorticoids with IV-CYC or MMF for at least 6 months. The clinical and pathological data were collected and analyzed.

RESULTS

The levels of 24-h urinary protein, anti-dsDNA antibody and SLE disease activity index were decreased, while the levels of albumin and complement 3 were increased after multi-target therapy. More than 90% of LN children achieved partial or complete remission within 6 months. In terms of adverse effects, there was no significant difference between the level of eGFR before and after multi-target therapy. During the follow-up period, four children had infection, two children had hyperuricemia, and one child had liver dysfunction. All of them improved after symptomatic therapy.

CONCLUSIONS

Multi-target therapy could be an effective treatment option with minimal adverse effects for LN children who are refractory to initial first-line induction therapies or had combined proliferative and membranous LN.

IMPACT

The multi-target therapy of glucocorticoids, mycophenolate mofetil and tacrolimus was adopted in 36 children with lupus nephritis. Multi-target therapy could be an effective treatment option for lupus nephritis children who are refractory to initial first-line induction therapies or had combined proliferative and membranous lupus nephritis. Adverse effects of multi-target therapy were infrequent and minimal that can be improved by symptomatic therapy.

Burden and Risk Factors of Contrast-Associated Acute Kidney Injury in Hospitalized Zambian Children: A Prospective Cohort Study at the University Teaching Hospitals

Background

Contrast-associated acute kidney injury (CAAKI) is defined as acute kidney injury (AKI) occurring within 72 hours of administration of contrast media (CM) and is linked to adverse outcomes including longer hospital stay, increased hospital mortality, and a higher risk of chronic kidney disease in later life. Risk factors for the development of CAAKI in the Zambian pediatric population have not been well studied.

Objectives

The objective of this study was to assess the burden of CAAKI, ascertain its risk factors, and describe short-term outcomes in hospitalized children at the University Teaching Hospitals (UTH) undergoing contrast-enhanced radiological investigations.

Methods

This was a prospective observational study of in-patients undergoing contrast-enhanced radiological procedures, between September 2020 and September 2021. The participants were recruited from the Children's Hospital, the Cancer Diseases Hospital, and the Pediatric Surgical Ward at the University Teaching Hospital in Lusaka, Zambia. The primary outcome variable was occurrence of AKI at 48 hours post CM administration. We used 2 criteria to define CAAKI in our study-the European Society of Urogenital Radiology (ESUR) and the Kidney Disease Improving Global Outcomes (KDIGO) 2012 criteria. Multivariable logistic regression models were formulated to assess for risk factors of CAAKI.

Results

Of the 201 enrolled participants, 123 (61.2%) were male and the median age of the participants was 5 years (interquartile range [IQR] = 3-10). The mean hemoglobin was 103 g/L (standard deviation [SD] = 26), median creatinine was 30.9 µmol/l (IQR = 22.6-43), and the glomerular filtration rate (GFR) was 102.5 mL/min/1.73 m2 (IQR = 76.2-129.4). Forty-six (22.9%) developed CAAKI using the ESUR compared with 4.5% (9/201) using the KDIGO criteria. Independent risk factors of CAAKI were receiving a higher dose of CM (adjusted odds ratio [aOR] = 2.54; 95% confidence interval [CI] = [1.12-5.74]), prematurity (aOR = 4.6; 95% CI = [1.05-16.7]), and a higher eGFR (aOR= 1.01; 95% CI = [1.01-1.02]). Females had higher odds of CAAKI (aOR = 2.48; 95% CI = [1.18-5.18]) when compared with males. One CAAKI participant (2.2%) died; none of the participants who developed CAAKI and survived required dialysis and most of them (90%) were discharged before day 7. Day 7 eGFR results had returned to or near baseline values for those whose creatinine results were available.

Conclusions

Using the ESUR criteria, a significant proportion (22.9%) of children undergoing contrast-enhanced computed tomography (CT) scans at the UTH developed CAAKI. In contrast, using the KDIGO criteria only 4.5% had CAAKI. Being born as a preterm baby, being female, having a higher eGFR at baseline, and receiving a higher dose of CM were found to be independent risk factors for CAAKI development in Zambian children. Most of the cases of CAAKI in children were transient and of little clinical significance as only a minority of patients developing CAAKI required kidney replacement therapy and all resolved by day 7 post administration of CM.

Early recognition and prevention of acute kidney injury in hospitalised children

Acute kidney injury is common in hospitalised children and is associated with poor patient outcomes. Once acute kidney injury occurs, effective therapies to improve patient outcomes or kidney recovery are scarce. Early identification of children at risk of acute kidney injury or at an early injury stage is essential to prevent progression and mitigate complications. Paediatric acute kidney injury is under-recognised by clinicians, which is a barrier to optimisation of inpatient care and follow-up. Acute kidney injury definitions rely on functional biomarkers (ie, serum creatinine and urine output) that are inadequate, since they do not account for biological variability, analytical issues, or physiological responses to volume depletion. Improved predictive tools and diagnostic biomarkers of kidney injury are needed for earlier detection. Novel strategies, including biomarker-guided care algorithms, machine-learning methods, and electronic alerts tied to clinical decision support tools, could improve paediatric acute kidney injury care. Clinical prediction models should be studied in different paediatric populations and acute kidney injury phenotypes. Research is needed to develop and test prevention strategies for acute kidney injury in hospitalised children, including care bundles and therapeutics.

Acute kidney injury after infant cardiac surgery: a comparison of pRIFLE, KDIGO, and pROCK definitions

BACKGROUND

KDIGO and pRIFLE classifications are commonly used in pediatric acute kidney injury (AKI). As a novel AKI definition, pROCK considered the high variability of serum creatinine in children. This study aimed to compare the above three definitions for AKI in infants undergoing cardiac surgery.

METHODS

We analyzed a clinical cohort of 413 infants undergoing cardiac surgery. AKI was defined and staged according to pRIFLE, KDIGO, and pROCK, respectively. Incidence differences and diagnostic agreement across definitions were assessed. The association between postoperative outcomes and AKI by each definition was investigated.

RESULTS

Postoperative AKI was identified in 185 (44.8%), 160 (38.7%), and 77 (18.6%) patients according to pRIFLE, KDIGO, and pROCK, respectively. The agreement between pRIFLE and KDIGO was almost perfect (κ = 0.88), while there was only a slight agreement between pROCK and them. AKI by pROCK was independently associated with adverse outcomes (p = 0.003) and prolonged mechanical ventilation (p = 0.002).

CONCLUSIONS

There were considerable differences in AKI incidence and staging among definitions. Compared with pRIFLE and KDIGO, AKI defined by pROCK was significantly reduced and better associated with postoperative adverse outcomes.

Detecting Neonatal AKI by Serum Cystatin C

SIGNIFICANCE STATEMENT

Serum creatinine is not a sensitive biomarker for neonatal AKI because it is confounded by maternal creatinine level, gestational age, and neonatal muscle mass. In this multicenter cohort study of 52,333 hospitalized Chinese neonates, the authors proposed serum cystatin C-related criteria (CyNA) for neonatal AKI. They found that cystatin C (Cys-C) is a robust and sensitive biomarker for identifying AKI in neonates who are at an elevated risk of in-hospital mortality and that CyNA detects 6.5 times as many cases as the modified Kidney Disease Improving Global Outcomes creatinine criteria. They also show that AKI can be detected using a single test of Cys-C. These findings suggest that CyNA shows promise as a powerful and easily applicable tool for detecting AKI in neonates.

BACKGROUND

Serum creatinine is not a sensitive biomarker for AKI in neonates. A better biomarker-based criterion for neonatal AKI is needed.

METHODS

In this large multicenter cohort study, we estimated the upper normal limit (UNL) and reference change value (RCV) of serum cystatin C (Cys-C) in neonates and proposed cystatin C-based criteria (CyNA) for detecting neonatal AKI using these values as the cutoffs. We assessed the association of CyNA-detected AKI with the risk of in-hospital death and compared CyNA performance versus performance of modified Kidney Disease Improving Global Outcomes (KDIGO) creatinine criteria.

RESULTS

In this study of 52,333 hospitalized neonates in China, Cys-C level did not vary with gestational age and birth weight and remained relatively stable during the neonatal period. CyNA criteria define AKI by a serum Cys-C of ≥2.2 mg/L (UNL) or an increase in Cys-C of ≥25% (RCV) during the neonatal period. Among 45,839 neonates with measurements of both Cys-C and creatinine, 4513 (9.8%) had AKI detected by CyNA only, 373 (0.8%) by KDIGO only, and 381 (0.8%) by both criteria. Compared with neonates without AKI by both criteria, neonates with AKI detected by CyNA alone had an increased risk of in-hospital mortality (hazard ratio [HR], 2.86; 95% confidence interval [95% CI], 2.02 to 4.04). Neonates with AKI detected by both criteria had an even higher risk of in-hospital mortality (HR, 4.86; 95% CI, 2.84 to 8.29).

CONCLUSIONS

Serum Cys-C is a robust and sensitive biomarker for detecting neonatal AKI. Compared with modified KDIGO creatinine criteria, CyNA is 6.5 times more sensitive in identifying neonates at elevated risk of in-hospital mortality.

Management of Acute Kidney Injury in Critically Ill Children

Acute kidney injury (AKI) is common in critically ill patients, affecting almost one in four critically ill children and one in three neonates. Higher stages of AKI portend worse outcomes. Identifying AKI timely and instituting appropriate measures to prevent and manage severe AKI is important, since it is independently associated with mortality. Methods to predict severe AKI should be applied to all critically ill patients. Assessment of volume status to prevent the development of fluid overload is useful to prevent adverse outcomes. Patients with metabolic or clinical complications of AKI need prompt kidney replacement therapy (KRT). Various modes of KRT are available, and the choice of modality depends most on the technical competence of the center, patient size, and hemodynamic stability. Given the significant risk of chronic kidney disease, patients with AKI require long-term follow-up. It is important to focus on improving awareness about AKI, incorporate AKI prevention as a quality initiative, and improve detection, prevention, and management of AKI with the aim of reducing acute and long-term morbidity and mortality.

A time-aware attention model for prediction of acute kidney injury after pediatric cardiac surgery

OBJECTIVE

Acute kidney injury (AKI) is a common complication after pediatric cardiac surgery, and the early detection of AKI may allow for timely preventive or therapeutic measures. However, current AKI prediction researches pay less attention to time information among time-series clinical data and model building strategies that meet complex clinical application scenario. This study aims to develop and validate a model for predicting postoperative AKI that operates sequentially over individual time-series clinical data.

MATERIALS AND METHODS

A retrospective cohort of 3386 pediatric patients extracted from PIC database was used for training, calibrating, and testing purposes. A time-aware deep learning model was developed and evaluated from 3 clinical perspectives that use different data collection windows and prediction windows to answer different AKI prediction questions encountered in clinical practice. We compared our model with existing state-of-the-art models from 3 clinical perspectives using the area under the receiver operating characteristic curve (ROC AUC) and the area under the precision-recall curve (PR AUC).

RESULTS

Our proposed model significantly outperformed the existing state-of-the-art models with an improved average performance for any AKI prediction from the 3 evaluation perspectives. This model predicted 91% of all AKI episodes using data collected at 24 h after surgery, resulting in a ROC AUC of 0.908 and a PR AUC of 0.898. On average, our model predicted 83% of all AKI episodes that occurred within the different time windows in the 3 evaluation perspectives. The calibration performance of the proposed model was substantially higher than the existing state-of-the-art models.

CONCLUSIONS

This study showed that a deep learning model can accurately predict postoperative AKI using perioperative time-series data. It has the potential to be integrated into real-time clinical decision support systems to support postoperative care planning.

Comparison of diagnostic criteria for acute kidney injury in critically ill children: a multicenter cohort study

Background

Substantial interstudy heterogeneity exists in defining acute kidney injury (AKI) and baseline serum creatinine (SCr). This study assessed AKI incidence and its association with pediatric intensive care unit (PICU) mortality under different AKI and baseline SCr definitions to determine the preferable approach for diagnosing pediatric AKI.

Methods

In this multicenter prospective observational cohort study, AKI was defined and staged according to the Kidney Disease: Improving Global Outcome (KDIGO), modified KDIGO, and pediatric reference change value optimized for AKI (pROCK) definitions. The baseline SCr was calculated based on the Schwartz formula or estimated as the upper normative value (NormsMax), admission SCr (AdmSCr) and modified AdmSCr. The impacts of different AKI definitions and baseline SCr estimation methods on AKI incidence, severity distribution and AKI outcome were evaluated.

Results

Different AKI definitions and baseline SCr estimates led to differences in AKI incidence, from 6.8 to 25.7%; patients with AKI across all definitions had higher PICU mortality ranged from 19.0 to 35.4%. A higher AKI incidence (25.7%) but lower mortality (19.0%) was observed based on the Schwartz according to the KDIGO definition, which however was overcome by modified KDIGO (AKI incidence: 16.3%, PICU mortality: 26.1%). Furthermore, for the modified KDIGO, the consistencies of AKI stages between different baseline SCr estimation methods were all strong with the concordance rates > 90.0% and weighted kappa values > 0.8, and PICU mortality increased pursuant to staging based on the Schwartz. When the NormsMax was used, the KDIGO and modified KDIGO led to an identical AKI incidence (13.6%), but PICU mortality did not differ among AKI stages. For the pROCK, PICU mortality did not increase pursuant to staging and AKI stage 3 was not associated with mortality after adjustment for confounders.

Conclusions

The AKI incidence and staging vary depending on the definition and baseline SCr estimation method used. The modified KDIGO definition based on the Schwartz method leads AKI to be highly relevant to PICU mortality, suggesting that it may be the preferable approach for diagnosing AKI in critically ill children and provides promise for improving clinicians’ ability to diagnose pediatric AKI.

Neonatal hypoxic ischemic encephalopathy increases acute kidney injury urinary biomarkers in a rat model

Hypoxic ischemic encephalopathy (HIE) is associated with acute kidney injury (AKI) in neonates with birth asphyxia. This study aimed to utilize urinary biomarkers to characterize AKI in an established neonatal rat model of HIE. Day 7 Sprague-Dawley rat pups underwent HIE using the Rice-Vannucci model (unilateral carotid ligation followed by 120 mins of 8% oxygen). Controls included no surgery and sham surgery. Weights and urine for biomarkers (NGAL, osteopontin, KIM-1, albumin) were collected the day prior, daily for 3 days post-intervention, and at sacrifice day 14. Kidneys and brains were processed for histology. HIE pups displayed histological evidence of kidney injury including damage to the proximal tubules, consistent with resolving acute tubular necrosis, and had significantly elevated urinary levels of NGAL and albumin compared to sham or controls 1-day post-insult that elevated for 3 days. KIM-1 significantly increased for 2 days post-HIE. HIE did not significantly alter osteopontin levels. Seven days post-start of experiment, controls were 81.2% above starting weight compared to 52.1% in HIE pups. NGAL and albumin levels inversely correlated with body weight following HIE injury. The AKI produced by the Rice-Vannucci HIE model is detectable by urinary biomarkers, which can be used for future studies of treatments to reduce kidney injury.

Pediatric Reference Change Value Optimized for Acute Kidney Injury: Multicenter Retrospective Study in China

OBJECTIVES

The standard definition of pediatric acute kidney injury (AKI) is evolving, especially for critically ill in the PICU. We sought to validate the application of the Pediatric Reference Change Value Optimized for Acute Kidney Injury in Children (pROCK) criteria in critically ill children.

DESIGN

Multicenter retrospective study.

SETTING

Six PICUs in mainland China.

PATIENTS

One thousand six hundred seventy-eight hospitalized children admitted to the PICU with at least two creatinine values within 7 days.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

AKI was diagnosed and staged according to the Pediatric Risk, Injury, Failure, Loss, End-Stage Renal Disease (pRIFLE), the Kidney Disease Improving Global Outcomes (KDIGO), and the pROCK criteria. Multiple clinical parameters were assessed and analyzed along with 90-day follow-up outcomes. According to the definitions of pRIFLE, KDIGO, and pROCK, the prevalence of AKI in our cohort of 1,678 cases was 52.8% (886), 39.0% (655), and 19.0% (318), respectively. The presence of AKI, as defined by pROCK, was associated with increased number of injured organs, occurrence of sepsis, use of mechanical ventilation, use of continuous renal replace therapy ( p < 0.05), higher Pediatric Risk of Mortality III score, and higher Pediatric Logistic Organ Dysfunction-2 score ( p < 0.001). The survival curve of 90-day outcomes showed that pROCK was associated with shorter survival time (LogRank p < 0.001), and pROCK definition was associated with better separation of the different stages of AKI from non-AKI ( p < 0.001).

CONCLUSIONS

In this retrospective analysis of AKI criteria in PICU admissions in China, pROCK is better correlated with severity and outcome of AKI. Hence, the pROCK criteria for AKI may have better utility in critically ill children.

Update on Pediatric Acute Kidney Injury

Acute kidney injury (AKI) is common in children and is associated with significant morbidity and mortality. In the last decade our understanding of AKI has improved significantly, and it is now considered a systemic disorder that affects other organs including heart, lung, and brain. In spite of its limitations, serum creatinine remains the mainstay in the diagnosis of AKI. However, newer approaches such as urinary biomarkers, furosemide stress test, and clinical decision support are being increasingly used and have the potential to improve the accuracy and timeliness of AKI diagnosis.

Safety considerations related to intravenous contrast agents in pediatric imaging

Intravenous contrast media are used in MRI, CT and US studies for anatomical evaluation and lesion characterization. Safety is always of paramount importance when administering any contrast media to children, and it is important for radiologists and ordering providers to be knowledgeable of the safety profiles and potential adverse events that can occur. This manuscript reviews the frequency and types of adverse events associated with intravenous contrast agents reported in the pediatric literature. Overall, intravenous contrast agents are very safe to use in children. However, familiarity with how to treat and prevent these uncommon events is crucial in preventing poor outcomes. In addition, an understanding of gadolinium deposition in tissues can help facilitate conversations with concerned physicians and parents. This review provides a concise yet comprehensive reference for radiologists and ordering providers on intravenous contrast safety considerations in the pediatric patient.

Prevalence and risk factors of trimethoprim/sulfamethoxazole-related acute kidney injury in pediatric patients: an observational study from a public database

BACKGROUND

Trimethoprim/sulfamethoxazole (TMP/SMZ) is widely used in various clinical settings. Studies have revealed that it may cause acute kidney injury (AKI) in adults. However, the correlation between the use of TMP/SMZ and renal injury in pediatric patients is still unclear. This study aimed to identify the impact of TMP/SMZ on the occurrence of AKI in children.

METHODS

A retrospective observational study was conducted using data of patients treated with TMP/SMZ from the Paediatric Intensive Care clinical database. A newly developed criterion was used for the diagnosis of AKI, and univariate and multiple logistic regression analyses were performed to identify the risk factors of TMP/SMZ-related renal injury.

RESULTS

A total of 113 patients were included. The prevalence of AKI was 21.2% (24/113). Univariate analysis indicated that the AKI group showed significantly higher baseline serum creatinine level (46.00 vs. 37.00 µmol/L; P=0.034) and in-hospital mortality rate [29.2% (7/24) vs. 9.0% (8/89); P=0.01] than that of the non-AKI group. Multivariate analysis revealed that the occurrence of AKI was significantly associated with increased baseline serum creatinine level [odds ratio (OR) =1.029; 95% CI: 1.006-1.053; P=0.014] and concurrent use of vancomycin (OR =5.349; 95% CI: 1.381-20.714; P=0.015). A proportion of 79.2% of patients (19/24) developed AKI within the first 10 days of TMP/SMZ use.

CONCLUSIONS

Elevated baseline serum creatinine level (≥40.25 µmol/L) and concurrent use of vancomycin were associated with the development of AKI in young patients. Further large multi-center prospective studies are necessary to confirm these relationships and validate their clinical significance.

Value of sufficient clean intermittent catheterization in urinary tract infection and upper urinary tract protection in children with neurogenic bladder

INTRODUCTION

Clean intermittent catheterization (CIC) is a mainstay in the management of neurogenic bladder.

OBJECTIVE

To assess the effect of CIC on urinary tract infection and upper renal tract function in pediatric patients with neurogenic bladder, and the influence of duration of CIC on these variables.

STUDY DESIGN

A retrospective study was performed in 67 pediatric patients with neurogenic bladder who started CIC between 2014 and 2019 at our institution. The febrile urinary tract infection (fUTI) rate, renal pelvis diameter (measured by antero-posterior renal pelvis diameter, APPD), bladder wall thickness (BWT) on ultrasound, and creatinine level at 6 months and 12 months of CIC were compared with baseline in all patients. The grade of vesicoureteral reflux (VUR) at 12 months of CIC were also compared with baseline.

RESULTS

There were no significant differences compared with baseline after 6 months of CIC in the rate of fUTI, APPD, and BWT (p > 0.05); however, all of these parameters significantly improved after 12 months of CIC (p < 0.05). The VUR grade was significantly reduced after 12 months of CIC(p = 0.03). There was no significant change in serum creatinine level with any duration of CIC (both p > 0.05).

DISCUSSION

Continuing CIC for more than 6 months had a beneficial influence on protecting the upper urinary tract. Complications of CIC, such as recurrent fUTI and lower urinary tract trauma, are more likely to occur in the early stage of CIC due to poor technique by the caregivers and poor patient compliance underscoring the importance of caregiver education. Study limitations include the retrospective nature and small sample size.

CONCLUSION

CIC for less than 6 months may have limited influence on renal protection; however, a longer duration of CIC (12 months) resulted in significant improvement in outcomes. This study demonstrates the importance of proper caregiver education to establish standardized CIC techniques and to improve CIC quality.

Loop Diuretics Are Associated with Increased Risk of Hospital-Acquired Acute Kidney Injury in Adult Patients: A Retrospective Study

Background: The association between loop diuretics and acute kidney injury (AKI) remains unclear. Methods: The population studied was selected from the Epidemiology of AKI in Chinese Hospitalized patients (EACH) study. Exposure to loop diuretics was defined as any filled prescription prior to the date when AKI was detected in patients with HA-AKI, and prior to the last date of SCr testing in those without AKI. The outcome was AKI, defined by the Kidney Disease Improving Global Outcomes criteria. Associations between loop diuretics and HA-AKI were examined by Cox proportional hazards models adjusted for baseline and time-dependent covariates. Results: Of the 150,020 patients, 16,437 (11.0%) were prescribed loop diuretics, and 5717 (3.8%) experienced HA-AKI events. The crude rates of HA-AKI in patients who were and were not prescribed loop diuretics were 1632 (9.9%) and 3262 (2.8%), respectively. A multivariate cox proportional hazards analysis showed that exposure to loop diuretics was associated with significantly increased risks of HA-AKI compared with non-users (hazard ratio (HR), 1.61; 95% CI (confidence interval), 1.55–1.67), other diuretics (HR, 1.09; 95% CI, 1.03–1.15), and osmotic diuretics (HR, 1.30; 95% CI, 1.20–1.42). Compared with other diuretics, the use of loop diuretics was associated with higher risks of HA-AKI in women, in patients without hypertension, in patients without heart failure, in patients without liver cirrhosis, and in patients not requiring surgery. Conclusions: Loop diuretics are widely used and are associated with increased risks of HA-AKI in hospitalized adults. Renal function should be more closely monitored during the use of loop diuretics.

Improving acute kidney injury diagnostic precision using biomarkers

Acute kidney injury (AKI) is common in hospitalized patients of all ages and is associated with significant morbidity and mortality. Accurate prediction and early identification of AKI is of utmost importance because no therapy exists to mitigate AKI once it has occurred. Yet, serum creatinine lacks adequate sensitivity and specificity, and quantification of urine output is challenging in incontinent children without indwelling bladder catheters. Integration of clinically available biomarkers have the potential to delineate unique AKI phenotypes that could have important prognostic and therapeutic implications. Plasma Cystatin C, urine neutrophil gelatinase associated lipocalin (NGAL) and the urinary product of tissue inhibitor metalloproteinase (TIMP-2) and insulin growth factor binding protein-7 (IGFBP7) are clinically available. These biomarkers have been studied in heterogenous populations across the age spectrum and in a variety of clinical settings for prediction of AKI. The purpose of this review is to describe and discuss the clinically available AKI biomarkers including how they have been used to delineate AKI phenotypes.

Effectiveness of Sodium Bicarbonate Infusion on Mortality in Critically Ill Children With Metabolic Acidosis

Objective: Metabolic acidosis often occurs in the paediatric intensive care unit (PICU). Although sodium bicarbonate (SB) has been widely used in paediatrics, data on the effect of SB on children with metabolic acidosis in the PICU are scarce.

Methods: Patients with metabolic acidosis who were treated with SB within 48 h of PICU admission were screened. Multivariate logistic regression, subgroup analysis, and propensity score matching (PSM) were used to investigate the relationships between SB infusion and clinical outcomes.

Results: A total of 1,595 patients with metabolic acidosis were enrolled in this study. In the multivariate logistic regression model, SB infusion was not correlated with in-hospital mortality (odds ratio (OR) 0.87, 95% confidence interval (CI) 0.47–1.63, p = 0.668), but was significantly correlated with hypernatraemia (OR 1.98, 95% CI 1.14–3.46, p = 0.016), hypokalaemia (OR 2.01, 95% CI 1.36–2.96, p < 0.001), and hypocalcaemia (OR 4.29, 95% CI 2.92–6.31, p < 0.001). In the pH value, lactate level, acute kidney injury level, age grouping, and anion gap level subgroups, the ORs for SB and in-hospital mortality were not statistically significant. After PSM, the results remained unchanged.

Conclusion: SB infusion does not reduce the in-hospital mortality of severely ill children with metabolic acidosis and increases the risk of hypernatraemia, hypokalaemia, and hypocalcaemia. More effort should be focused on eliminating the causes of metabolic acidosis rather than SB infusion.

Advances in pediatric acute kidney injury

The objective of this study was to inform the pediatric nephrologists of recent advances in acute kidney injury (AKI) epidemiology, pathophysiology, novel biomarkers, diagnostic tools, and management modalities. Studies were identified from PubMed, EMBASE, and Google Scholar for topics relevant to AKI. The bibliographies of relevant studies were also reviewed for potential articles. Pediatric (0-18 years) articles from 2000 to May 2020 in the English language were included. For epidemiological outcomes analysis, a meta-analysis on data regarding AKI incidence, mortality, and proportion of kidney replacement therapy was performed and an overall pooled estimate was calculated using the random-effects model. Other sections were created highlighting pathophysiology, novel biomarkers, changing definitions of AKI, evolving tools for AKI diagnosis, and various management modalities. AKI is a common condition seen in hospitalized children and the diagnosis and management have shown to be quite a challenge. However, new standardized definitions, advancements in diagnostic tools, and the development of novel management modalities have led to increased survival benefits in children with AKI. IMPACT: This review highlights the recent innovations in the field of AKI, especially in regard to epidemiology, pathophysiology, novel biomarkers, diagnostic tools, and management modalities.

Higher ambient nitrogen dioxide is associated with an elevated risk of hospital-acquired acute kidney injury

BACKGROUND

Previous studies have suggested that long-term exposure to air pollution increases the risk of chronic kidney disease and its progression. However, the effect of air pollution on the risk of acute kidney injury (AKI) has not been studied. We aim to evaluate the transient effect of air pollution on the risk of hospital-acquired AKI (HA-AKI).

METHODS

We selected from the Epidemiology of AKI in Chinese Hospitalized patients cohort AKI cases in which the onset date could be unambiguously determined. We obtained city-specific daily averages of the ambient level of particulate matter (2.5 μm and 10 μm), carbon monoxide, nitrogen dioxide (NO₂), sulfur dioxide (SO₂) and ozone (O₃) from the Ministry of Environmental Protection of China. We used the time-stratified case-crossover approach to examine the association between the ambient level of air pollutants and the risk of HA-AKI in the selected cases.

RESULTS

A total of 11 293 AKI cases that met the inclusion and exclusion criteria were selected. In univariable analysis, the ambient levels of NO₂ and SO₂ were significantly associated with the risk of HA-AKI. In the multivariable analysis that incorporated all six pollutants in the same model, NO₂ was the sole pollutant whose level remained associated with the risk of AKI (P < 0.001). The relationship between the level of NO₂ and the risk of HA-AKI appeared to be linear, with an estimated odds ratio of 1.063 (95% confidence interval 1.026-1.101) for each increment of 1 median absolute deviation in the exposure. The association was consistent across the subgroups stratified by age, gender, baseline estimated glomerular filtration rate, AKI severity, need for intensive care and season.

CONCLUSIONS

Higher ambient levels of NO₂ are associated with an increased risk of HA-AKI in hospitalized adults in China.

AACC Guidance Document on Laboratory Investigation of Acute Kidney Injury

BACKGROUND

Acute kidney injury (AKI) is a sudden episode of kidney damage or failure affecting up to 15% of hospitalized patients and is associated with serious short- and long-term complications, mortality, and health care costs. Current practices to diagnose and stage AKI are variable and do not factor in our improved understanding of the biological and analytical variability of creatinine. In addition, the emergence of biomarkers, for example, cystatin C, insulin-like growth factor binding protein 7, and tissue inhibitor of metalloproteinases 2, and electronic notification tools for earlier detection of AKI, highlights the need for updated recommendations to address these developments.

CONTENT

This AACC Academy guidance document is intended to provide laboratorians and clinicians up-to-date information regarding current best practices for the laboratory investigation of AKI. Topics covered include: clinical indications for further investigating potential AKI, analytical considerations for creatinine assays, the impact of biological variability on diagnostic thresholds, defining "baseline" creatinine, role of traditional markers (urine sodium, fractional excretion of sodium, fractional excretion of urea, and blood urea-to-creatinine ratio), urinary microscopic examination, new biomarkers, improving AKI-associated test utilization, and the utility of automated AKI alerts.

SUMMARY

The previous decade brought us a significant number of new studies characterizing the performance of existing and new biomarkers, as well as potential new tools for early detection and notification of AKI. This guidance document is intended to inform clinicians and laboratorians on the best practices for the laboratory investigation of AKI, based on expert recommendations where the preponderance of evidence is available.

Trajectory of AKI in hospitalized pediatric patients - impact of duration and repeat events

BACKGROUND

Peak severity of acute kidney injury (AKI) is associated with mortality in hospitalized pediatric patients. Other factors associated with AKI, such as number of AKI events, severity of AKI events, and time spent in AKI may also have associations with mortality. Characterization of these events could help to evaluate patient outcomes.

METHODS

Pediatric inpatients (<19 years of age) from 2011-2019 who were not on maintenance renal replacement therapy and had least one serum creatinine (SCr) obtained during hospital admission were included. Percent change in SCr from the minimum value in the prior 7 days was used for AKI staging according to KDIGO criteria. Maximum value for age appropriate normal was used for patients with only one SCr. Repeat AKI events were classified in patients if KDIGO criteria was met more than once with at least one SCr value between episodes that did not meet KDIGO criteria.Patient demographics were summarized and incidence of AKI was determined along with associations with mortality. AKI characterizations for the admission were developed including: AKI, repeat (>1) AKI, AKI severity (maximum KDIGO stage), and total number of AKI events. AKI duration as percent admission days in a KDIGO stage and AKI percent velocity were determined. Kaplan-Meier analysis was performed for time to 30 day survival by AKI characterization. A mixed effects logistic regression model with mortality as the dependent variable and nested in patients was developed incorporating patient variables and AKI characterizations.

RESULTS

A total of 184,297 inpatient encounters met study criteria (male 51.7%, Age 7.8 years (IQR 2.5, 13.8), mortality 0.56%). Hospital length of stay was 1.9 days (IQR 0.37, 4.8 days), 15.4% had an intensive care unit admission and 12.2% underwent mechanical ventilation. AKI occurred in 5.6% (n = 10,246) of admissions (Stage I = 4.5% (n = 8,310), Stage II = 1.3% (n = 2,363), Stage III=0.77% (n = 1,423)) and repeat AKI events occurred in 1.92% (n = 3,558). AKI was associated with mortality (OR 6.0, 95% CI 4.8, 7.6, p < 0.001) and increasing severity (KDIGO maximum stage) was associated with increased mortality. Multiple AKI events were also associated with mortality (p < 0.001),. Duration of AKI was associated with mortality (p < 0.001) but AKI velocity was not (p > 0.05).

CONCLUSIONS

AKI occurs in 5.6% of the pediatric inpatient population and multiple AKI events occur in ∼30% of these patients. Maximum KDIGO stage is most strongly associated with mortality. Multiple AKI events and AKI duration should also be considered when evaluating patient outcomes.

Acute kidney injury: epidemiology and course in critically ill children

BACKGROUND

Acute kidney injury (AKI) is a major cause of morbidity and mortality in critically ill children. The aim of this paper was to describe the prevalence and course of AKI in critically ill children and to compare different AKI classification criteria.

METHODS

We conducted a retrospective observational study in our multi-disciplinary Pediatric Intensive Care Unit (ICU) from January 2015 to December 2018. All patients from birth to 16 years of age who were admitted to the pediatric ICU were included. The Kidney Disease Improving Global Outcomes (KDIGO) definition was considered as the reference standard. We compared the incidence data assessed by KDIGO, pediatric risk, injury, failure, loss of kidney function and end- stage renal disease (pRIFLE) and pediatric reference change value optimised for AKI (pROCK).

RESULTS

Out of 7505 patients, 9.2% developed AKI by KDIGO criteria. The majority (59.8%) presented with stage 1 AKI. Recovery from AKI was observed in 70.4% of patients within 7 days from diagnosis. Both pRIFLE and pROCK were less sensitive compared to KDIGO criteria for the classification of AKI. Patients who met all three-KDIGO, pRIFLE and pROCK criteria had a high mortality rate (35.0%).

CONCLUSION

Close to one in ten patients admitted to the pediatric ICU met AKI criteria according to KDIGO. In about 30% of patients, AKI persisted beyond 7 days. Follow-up of patients with persistent kidney function reduction at hospital discharge is needed to reveal the long-term morbidity due to AKI in the pediatric ICU.

Impact of and risk factors for pediatric acute kidney injury defined by the pROCK criteria in a Chinese PICU population

BACKGROUND

The definition of pediatric AKI continues to evolve. We aimed to find a better AKI definition to predict outcomes and identify risk factors for AKI in a Chinese PICU.

METHODS

This study consisted of 3338 patients hospitalized in a Chinese PICU between 2016 and 2018. AKI was defined and staged using pROCK criteria, which were compared with KDIGO criteria. AKI outcomes, including mortality, daily cost and length of stay (LOS), were assessed. Risk factors for AKI were also estimated.

RESULTS

The incidence of AKI in the PICU was 7.7% according to pROCK criteria. The characteristics of patients with KDIGO-defined AKI who did not meet the pROCK were similar to those without AKI. pROCK outperformed KDIGO in predicting mortality with a higher c index in the Cox models (0.81 versus 0.79, P = 0.013). AKI, as well as AKI stages, were associated with higher mortality (HR: 10.5, 95%CI: 6.66-19.5), daily cost (β = 2064, P < 0.01) and LOS (β = 2.30, P < 0.01). Age, comorbidities, mechanical ventilation (MV), pediatric critical illness score (PCIS) and exposure to drugs had significant influence on AKI occurrence.

CONCLUSIONS

The mortality predictability of pROCK was slightly greater than that of KDIGO. Older age, underlying comorbidities, MV, decreased PCIS and exposure to drugs were potential risk factors for AKI.

IMPACT

Two AKI criteria, pROCK and KDIGO, were significantly associated with an increased risk of mortality and pROCK was slightly greater than that of KDIGO. Older age, comorbidities, mechanical ventilation, decreased PCIS and exposure to drugs were potential risk factors for AKI. This study first used the pROCK criteria to provide an epidemiologic description of pediatric AKI in Chinese PICU. This study compared the AKI outcomes across the pROCK and KDIGO AKI criteria, indicating the prior utility for AKI classification in Chinese children. This study indicated that the potential risk factors for AKI were older age, comorbidities, mechanical ventilation, decreased PCIS and exposure to drugs.

Association of Ibuprofen Prescription With Acute Kidney Injury Among Hospitalized Children in China

IMPORTANCE

Ibuprofen is widely used in children worldwide, especially in those with cancer, fever, or trauma. However, large and high-quality studies of the association between ibuprofen and acute kidney injury (AKI) in children have been lacking.

OBJECTIVE

To examine the association between the use of ibuprofen and the risk of hospital-acquired AKI in hospitalized children in China.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study analyzed the cohort of the Epidemiology of AKI in Chinese Hospitalized Patients (EACH) study, a large, multicenter retrospective study of 3 044 023 patients who were admitted to 1 of 25 academic medical centers in China between January 1, 2013, and December 31, 2015. Patient-level data were obtained from the electronic health record system of the participating centers. Hospitalized children aged 1 month to 18 years who had prescriptions and a certain number of serum creatinine (SCr) tests were included. Children with end-stage renal disease, community-acquired AKI, low baseline SCr level (<10 μmol/L), high standardized baseline SCr level (>4 times the sex- and age-specific reference value), or missing diagnosis code were excluded. Data analysis was conducted from January 1, 2020, to August 30, 2020.

EXPOSURES

Exposure to ibuprofen was coded as a time-dependent dichotomous variable.

MAIN OUTCOMES AND MEASURES

Baseline SCr level was calculated for each patient as the mean of all available SCr values between the 30 days prior to admission and the first SCr testing within the first 3 days of hospitalization. Acute kidney injury was defined as an increase in SCr level of 26.5 μmol/L or higher within 48 hours or by 50% or more over the baseline value, according to the Kidney Disease: Improving Global Outcomes guidelines.

RESULTS

Among the 50 420 children (mean [SD] age, 5.0 [5.2] years; 30 640 boys [60.8%]) included in this study, 5526 (11.0%) used ibuprofen and 3476 (6.9%) developed hospital-acquired AKI during hospitalization. Ibuprofen use was associated with a statistically significantly increased risk of hospital-acquired AKI (hazard ratio [HR], 1.23; 95% CI, 1.14-1.34) after adjusting for confounders. Ibuprofen use was associated with a greater hazard in children who had chronic kidney disease vs those without (HR, 2.31 [95% CI, 1.73-3.10] vs 1.19 [95% CI, 1.09-1.29]), required intensive care vs those without this need (HR, 1.47 [95% CI, 1.24-1.75] vs 1.18 [95% CI, 1.07-1.29]), or were older vs younger (>10 years and >1 year to 10 years vs 1 month to 1 year) (HR, 1.64 [95% CI, 1.32-2.05]; 1.36 [95% CI, 1.23-1.52] vs 0.99 [95% CI, 0.86-1.13]). Dose-response analysis suggested that the association of ibuprofen with the risk of hospital-acquired AKI was dose-dependent.

CONCLUSIONS AND RELEVANCE

This study found that ibuprofen was widely used and associated with an increased risk of hospital-acquired AKI in hospitalized children in China. The judicious use of ibuprofen and close monitoring of kidney function in children are needed.

Re-evaluating Renal Angina Index: An Authentic, Evidence-Based Instrument for Acute Kidney Injury Assessment: Critical Appraisal

Background/Introduction: Renal angina index (RAI) used to calculate and accurately predict risk for the development of acute kidney injury (AKI) has been heavily explored. AKI is traditionally diagnosed by an increase in serum creatinine (SCr) concentration or oliguria, both of which are neither specific nor sensitive, especially among children. An RAI score may be calculated by combining objective signs of kidney dysfunction (such as SCr) and patient context, such as AKI risk factors, thus potentially serving as a more accurate indicator for AKI. Objective: Due to the propitious and novel nature of RAI, this editorial commentary aims to analyze the current literature on RAI and determine how well RAI serves as a predictor of AKI outcomes. Method: A comprehensive literature search was conducted in PubMed/Medline and Google Scholar between January 2012 and July 2020. Literature included the prognostic aspect of early prediction of AKI in the pediatric and adult population via RAI. Results: The initial literature search included 149 studies, and a total of 10 studies reporting the outcomes of interest were included. The overall sample size across these studies was 11,026. The predictive ability of RAI had a pooled (95% CI) sensitivity of 79.21%, specificity of 73.22%, and negative predictive value of 94.83%. Conclusion: RAI shows benefit in the prediction of AKI among adult and pediatric populations. However, there is a lack of sufficient data, and further prospective studies are needed in pediatric populations to use RAI as a principal AKI indicator among clinicians.

Be aware of acute kidney injury in critically ill children with COVID-19

BACKGROUND

Acute kidney injury (AKI) is a common complication of critically ill adult patients with COVID-19. However, currently, no studies investigate kidney impairment in children with COVID-19. We investigated incidence and treatment of AKI in pediatric patients with COVID-19 in Wuhan Children's Hospital during the early stages of the COVID-19 pandemic and discuss possible mechanisms of AKI related to SARS-CoV-2 infection.

METHODS

By extracting data from electronic medical records, we conducted a retrospective observational study of kidney involvement in confirmed pediatric COVID-19 cases in Wuhan Children's Hospital during the coronavirus outbreak, from January 24 to March 20, 2020. Clinical presentations, clinical courses, laboratory findings, and medical interventions are described below.

RESULTS

Among 238 confirmed COVID-19 cases, only three were critically ill and needed intensive care unit (ICU) admission. All three developed AKI, but AKI was not detected in any non-critically ill patients outside the ICU. Two of the three patients with AKI had prodromal gastrointestinal symptoms. Significantly elevated interleukin-6 (IL-6) levels and complement activation were observed in these patients with AKI. The three patients with AKI were treated with plasma exchange (PE) and continuous kidney replacement therapy (CKRT), resulting in one complete recovery, one partial recovery, and one mortality due to critical illness.

CONCLUSIONS

Critically ill children with COVID-19 may develop AKI, especially following prodromal gastrointestinal symptoms. An inflammatory storm and complement-mediated injury may underlie AKI development in children with COVID-19. Our study supports implantation of PE and CKRT in management of critically ill patients with AKI.

Acute kidney injury among hospitalized children with cancer

BACKGROUND

Few studies to date have analyzed the epidemiology of acute kidney injury (AKI) in children with cancer in developing countries. The aim of this study was to assess the incidence, risk profile and outcomes of AKI in Chinese children hospitalized with cancer.

METHODS

This multi-center study analyzed Chinese children hospitalized with cancer in 2013-2015. Electronic hospital and laboratory databases were screened to select pediatric patients with malignancy who had at least two Scr results within any 7-day window during their first 30 days of hospitalization. AKI events were identified and staged according to Kidney Disease Improving Global Outcomes (KDIGO) criteria. The incidence of and risk factors for AKI were analyzed, as were mortality rate, incidence of kidney recovery, and length of hospital stay.

RESULTS

Of the 9828 children with cancer, 1657 (16.9%) experienced AKI events, including 549 (5.6%) community-acquired (CA-AKI) and 1108 (11.3%) hospital-acquired AKI (HA-AKI) events. The three types of cancer with the highest incidence of AKI were urinary system cancer (25.8%), hepatic cancer (19.4%), and retroperitoneal malignancies (19.1%). The risk factor profiles of CA-AKI and HA-AKI events differed, with many HA-AKI events due to treatment with nephrotoxic agents. In-hospital death rates were 5.4% (90 of 1657) in children with and 0.9% (74 of 8171) in children without AKI events. AKI events were also associated with longer hospitalization and higher daily costs.

CONCLUSIONS

AKI events are common among Chinese children hospitalized for cancer and are associated with adverse in-hospital outcomes.

Clinicopathological Analysis of 34 Cases of Primary Antineutrophil Cytoplasmic Antibody-Associated Vasculitis in Chinese Children

Background: This study aimed to summarize the clinicopathological features and prognostic risk factors of primary antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) in children. Methods: Clinical and prognostic data for children admitted to our center with AAV between September 2003 and September 2020 were studied retrospectively. The incidence and risk factors of end-stage renal disease (ESRD) were calculated and analyzed. Results: Thirty-four children were enrolled; 28 were female, with a median onset age of 10 years. Except for one case negative for ANCA, the other 33 patients were diagnosed with microscopic polyangiitis (MPA). The most frequently involved organ was the kidney (100.0%), followed by the lungs (58.8%) and heart (50.0%). Twenty children (58.8%) progressed to ESRD with a median course of 3 months, and they were more likely to present respiratory and cardiovascular system involvement than were the non-ESRD group (P < 0.05). Patients in the ESRD group also had a higher serum creatinine level, 24-h protein excretion, Pediatric Vasculitis Activity Score (PVAS), and a lower level of estimated glomerular filtration rate (eGFR), hemoglobin, and complement C3 than had those in the non-ESRD group (P < 0.05). The main pathological manifestations were crescentic and sclerotic classes in the ESRD group and focal class in the non-ESRD group. After 6 months of induction therapy, 90.0% of cases achieved complete or partial remission. The multivariate logistic regression model showed that baseline eGFR < 60 ml/min/1.73 m² was an independent risk factor for progressing to ESRD (OR = 0.016, 95% CI = 0.001~0.412, P = 0.012). Conclusions: AAV in children usually occurs in teenage girls, and the most commonly involved organ is the kidney, of which hematuria is the most common symptom, followed by proteinuria, abnormal renal function (eGFR < 90 ml/min/1.73 m²), etc. The primary type of AAV is MPA. Nearly 60% of patients progressed to ESRD with a median course of 3 months. Baseline eGFR < 60 ml/min/1.73 m² is an independent risk factor for ESRD progression in AAV children.

Prognostic Impact of Parameters of Metabolic Acidosis in Critically Ill Children with Acute Kidney Injury: A Retrospective Observational Analysis Using the PIC Database

Acute kidney injury (AKI) is a major complication of sepsis that induces acid-base imbalances. While creatinine levels are the only indicator for assessing the prognosis of AKI, prognostic importance of metabolic acidosis is unknown. We conducted a retrospective observational study by analyzing a large China-based pediatric critical care database from 2010 to 2018. Participants were critically ill children with AKI admitted to intensive care units (ICUs). The study included 1505 children admitted to ICUs with AKI, including 827 males and 678 females. The median age at ICU admission was 22 months (interquartile range 7–65). After a median follow-up of 10.87 days, 4.3% (65 patients) died. After adjusting for confounding factors, hyperlactatemia, low pH, and low bicarbonate levels were independently associated with 28-day mortality (respective odds ratio: 3.06, 2.77, 2.09; p values: <0.01, <0.01, <0.01). The infection had no interaction with the three parameters. The AKI stage negatively interacted with bicarbonate and pH but not lactate. The current study shows that among children with AKI, hyperlactatemia, low pH, and hypobicarbonatemia are associated with 28-day mortality.

Proton pump inhibitors and the risk of hospital-acquired acute kidney injury in children

BACKGROUND

To evaluate the association between use of proton pump inhibitor (PPI) and the risk of hospital-acquired acute kidney injury (HA-AKI) in hospitalized children.

METHODS

We conducted a multicenter retrospective cohort study in hospitalized children aged 1 month to 18 years from 25 tertiary hospitals across China from 2013 to 2015. Patient-level data were obtained from the electronic hospitalization databases. AKI was defined and staged using the serum creatinine (SCr) data according to the Kidney Disease Improving Global Outcomes (KDIGO) criteria.

RESULTS

Among 42,232 children analyzed, 11,496 (27.2%) used PPI, 1,760 (4.2%) used histamine 2 receptor antagonist (H2RA), and 3,514 (8.3%) had HA-AKI during hospitalization. Over 85% of PPIs were prescribed for prophylaxis of gastro-duodenal lesions in children. The use of PPI was associated with a significantly increased risk of HA-AKI compared with both non-users [odds ratio (OR), 1.37; 95% confidence interval (CI), 1.23-1.53)] and H2RA users (OR, 1.24; 95% CI, 1.01-1.52). The associations were consistent across children of different age range, gender, subtypes of PPIs and methods of administration. A larger effect was observed in children with chronic kidney disease (OR, 3.37; 95% CI, 2.46-4.62) and those needed intensive care (OR, 1.54; 95% CI, 1.33-1.78). The risk of HA-AKI was increased even within the recommended dosage range of PPI.

CONCLUSIONS

PPIs were widely used and associated with an increased risk of HA-AKI in hospitalized children in China.

Prediction of Acute Kidney Injury on Admission to Pediatric Intensive Care

OBJECTIVES

Up to 37% of children admitted to the PICU develop acute kidney injury as defined by Kidney Disease: Improving Global Outcomes criteria. We describe the prevalence of acute kidney injury in a mixed pediatric intensive care cohort using this criteria. As tools to stratify patients at risk of acute kidney injury on PICU admission are lacking, we explored the variables at admission and day 1 that might predict the development of acute kidney injury.

DESIGN

Single-center retrospective observational study.

SETTING

Thirty-six-bed surgical/medical tertiary PICU.

PATIENTS

Children from birth to less than or equal to 16 years old admitted between 2015 and 2018.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Clinical data were extracted from the PICU clinical information system. Patients with baseline creatinine at admission greater than 20 micromol/L above the calculated normal creatinine level were classified as "high risk of acute kidney injury." Models were created to predict acute kidney injury at admission and on day 1. Out of the 7,505 children admitted during the study period, 738 patients (9.8%) were classified as high risk of acute kidney injury at admission and 690 (9.2%) developed acute kidney injury during PICU admission. Compared to Kidney Disease: Improving Global Outcomes criteria as the reference standard, high risk of acute kidney injury had a lower sensitivity and higher specificity compared with renal angina index greater than or equal to 8 on day 1. For the admission model, the adjusted odds ratio of developing acute kidney injury for high risk of acute kidney injury was 4.2 (95% CI, 3.3-5.2). The adjusted odds ratio in the noncardiac cohort for high risk of acute kidney injury was 7.3 (95% CI, 5.5-9.7). For the day 1 model, odds ratios for high risk of acute kidney injury and renal angina index greater than or equal to 8 were 3.3 (95% CI, 2.6-4.2) and 3.1 (95% CI, 2.4-3.8), respectively.

CONCLUSIONS

The relationship between high risk of acute kidney injury and acute kidney injury needs further evaluation. High risk of acute kidney injury performed better in the noncardiac cohort.

Community-Based Epidemiology of Hospitalized Acute Kidney Injury

BACKGROUND

Acute kidney injury (AKI) may lead to short- and long-term consequences in children, but its epidemiology has not been well described at a population level and outside of ICU settings.

METHODS

In a large, diverse pediatric population receiving care within an integrated health care delivery system between 2008 and 2016, we calculated age- and sex-adjusted incidences of hospitalized AKI using consensus serum creatinine (SCr)-based diagnostic criteria. We also investigated the proportion of AKI detected in non-ICU settings and the rates of follow-up outpatient SCr testing after AKI hospitalization.

RESULTS

Among 1 500 546 children, the mean age was 9.8 years, 49.0% were female, and 33.1% were minorities. Age- and sex-adjusted incidence of hospitalized AKI among the entire pediatric population did not change significantly across the study period, averaging 0.70 (95% confidence interval: 0.68-0.73) cases per 1000 person-years. Among the subset of hospitalized children, the adjusted incidence of AKI increased from 6.0% of hospitalizations in 2008 to 8.8% in 2016. Approximately 66.7% of AKI episodes were not associated with an ICU stay, and 54.3% of confirmed, unresolved Stage 2 or 3 AKI episodes did not have outpatient follow-up SCr testing within 30 days postdischarge.

CONCLUSIONS

Community-based pediatric AKI incidence was ∼1 per 1000 per year, with two-thirds of cases not associated with an ICU stay and more than one-half not receiving early outpatient follow-up kidney function testing. Further efforts are needed to increase the systematic recognition of AKI in all inpatient settings with appropriate, targeted postdischarge kidney function monitoring and associated management.

Biomarker Panels in Critical Care

Biomarker panels have the potential to advance the field of critical care medicine by stratifying patients according to prognosis and/or underlying pathophysiology. This article discusses the discovery and validation of biomarker panels, along with their translation to the clinical setting. The current literature on the use of biomarker panels in sepsis, acute respiratory distress syndrome, and acute kidney injury is reviewed.

Epidemiology and outcomes of acute kidney injury in hospitalized cancer patients in China

Acute kidney injury (AKI) is a common complication in cancer patients, but the data are lacking in Asian countries. We aimed to assed the epidemiology, correlated risk factors and outcomes of AKI in cancer patients from China. We conducted a nationwide cohort study of cancer patients who were admitted to 25 general and children hospitals across China from January 1, 2013 to December 31, 2015. We obtained patient-level data from the electronic hospitalization information system and laboratory databases of all inpatients who had at least two serum creatinine tests within any 7-day window during their first 30 days of hospitalization. AKI was defined and staged according to Kidney Disease Improving Global Outcomes criteria. Incidence rate and risk factor profiles for AKI were examined. Outcomes of interest included in-hospital mortality, length of stay and daily costs. A total of 136,756 adult cancer patients were assessed in our study. The overall incidence of AKI was 7.5%, of which 1.6% were community acquired and 5.9% hospital acquired. The top three cancer types with high incidence of AKI were bladder cancer, leukemia, and lymphoma. Risk factors for community-acquired and hospital-acquired AKI were similar, including age, increased baseline serum creatinine, shock and urinary tract obstruction. In-hospital death occurred in 12.0% with AKI vs. 0.9% cancer patients without AKI. After adjustment for confounders, the severe AKI was associated with higher risk of in-hospital death, prolonged length of stay and higher daily costs. Clinicians should increase their awareness of AKI in hospitalized cancer patients.