Epidemiology and Outcome of Acute Kidney Injury According to Pediatric Risk, Injury, Failure, Loss, End-Stage Renal Disease and Kidney Disease: Improving Global Outcomes Criteria in Critically Ill Children-A Prospective Study

Renal angina index in critically ill children as an applicable and reliable tool in the prediction of severe acute kidney injury: Two tertiary centers' prospective observational study from the Middle East

Acute kidney damage (AKI) is a common cause of pediatric intensive care unit (PICU) admissions. Implementing a reno-protective strategy for AKI prediction can significantly enhance outcomes. The renal angina index (RAI) is a risk stratification tool used to predict severe AKI. We aim to assess the reliability and accuracy of the RAI scoring system in predicting AKI as compared to other conventional AKI markers. A prospective, observational study was conducted in the PICU of 2 tertiary medical centers in the Middle East. A total of 446 patients, aged 1-month to 14-years, without chronic kidney disease were enrolled. The RAI was calculated using the renal risk and renal injury score within the first 8 to 12 hours of admission. The accuracy of RAI was compared to changes in serum creatinine from baseline. The outcome was assessed on Day 3 for presence of AKI according to the kidney disease improving global outcome (KDIGO) criteria and associated sequelae. A positive RAI (RA+) was defined as RAI readings ≥ 8. Among the patients, 89 (19.9%) had a positive RAI within the first 8 to 12 hours of admission. The RA + group had a significantly higher occurrence of Day 3 severe AKI (KDIGO stages 2&3) compared to the RA- group (60.6% vs 4.2%, P < .001). The RA + group also had a significantly higher utilization of renal replacement therapy (RRT) (21.3% vs 1.1%, P < .001), longer mean PICU length of stay in days (11.1 ± 3.5 vs 5.5 ± 2.1, P < .001), and increased mortality (31.4% vs 2.8%, P < .001) compared to the RA- group. The RAI score demonstrated superior predictive ability for Day 3 AKI, with a sensitivity of 72%, specificity of 95%, and area under the curve (AUC) of 0.837, compared to changes in serum creatinine from baseline (sensitivity: 65%, specificity: 89%, AUC: 0.773), fluid overload (sensitivity: 43.7%, specificity: 79%, AUC: 0.613), and illness severity scores (sensitivity: 52.4%, specificity: 80.5%, AUC: 0.657). RAI proved to be a reliable and rapid bedside test for identifying critically ill children at risk of developing severe AKI. This enables physicians to implement reno-protective measures and intervene early, thereby improving prognosis.

Sepsis associated acute kidney injury in pediatric intensive care unit

BACKGROUND

We aimed to compare the acute kidney injury (AKI) incidence in pediatric septic shock patients according to the three different classifications.

METHODS

We analyzed retrospectively 52 patients with severe sepsis between January 2019 and December 2019.

RESULTS

While 21 patients have been diagnosed with SA-AKI according to the pRIFLE criteria, 20 children have been diagnosed according to the AKIN criteria, and 21 children have been diagnosed according to the KDIGO criteria. Older age, lower platelet count were determined as independently risk factor for SA-AKI. Older age and higher PRISM score were associated with mortality. According to Canonical correlation coefficients, pRIFLE is the most successful classification to distinguish AKI state. The canonical correlation coefficients for pRIFLE, KDIGO, and AKIN were 0.817, 0.648, and 0.615, respectively.

CONCLUSION

Although AKI incidence was similar between the three classifications, pRIFLE was the most successful classification to distinguish AKI state.

Reliability of glomerular filtration rate estimating formulas compared to iohexol plasma clearance in critically ill children

Accurate renal function assessment is crucial to guide intensive care decision-making and drug dosing. Estimates of glomerular filtration rate (eGFR) are routinely used in critically ill children; however, these formulas were never evaluated against measured GFR (mGFR) in this population. We aimed to assess the reliability of common eGFR formulas compared to iohexol plasma clearance (CL_iohexol) in a pediatric intensive care (PICU) population. Secondary outcomes were the prevalence of acute kidney injury (AKI) (by pRIFLE criteria) and augmented renal clearance (ARC) (defined as standard GFR for age + 2 standard deviations (SD)) within 48 h after admission based on mGFR and eGFR by the revised Schwartz formula and the difference between these two methods to diagnose AKI and ARC. In children, between 0 and 15 years of age, without chronic renal disease, GFR was measured by CL_iohexol and estimated using 26 formulas based on creatinine (Scr), cystatine C (CysC), and betatrace protein (BTP), early after PICU admission. eGFR and mGFR results were compared for the entire study population and in subgroups according to age, using Bland-Altman analysis with calculation of bias, precision, and accuracy expressed as percentage of eGFR results within 30% (P30) and 10% (P10) of mGFR. CL_iohexol was measured in 98 patients. Mean CL_iohexol (± SD) was 115 ± 54 ml/min/1.73m². Most eGFR formulas showed overestimation of mGFR with large bias and poor precision reflected by wide limits of agreement (LoA). Bias was larger with CysC- and BTP-based formulas compared to Scr-based formulas. In the entire study population, none of the eGFR formulas showed the minimal desired P30 > 75%. The widely used revised Schwartz formula overestimated mGFR with a high percentage bias of - 18 ± 51% (95% confidence interval (CI) - 29; - 9), poor precision with 95% LoA from - 120 to 84% and insufficient accuracy reflected by P30 of only 51% (95% CI 41; 61), and P10 of 21% (95% CI 13; 66) in the overall population. Although performance of Scr-based formulas was worst in children below 1 month of age, exclusion of neonates and younger children did not result in improved agreement and accuracy. Based on mGFR, prevalence of AKI and ARC within 48 h was 17% and 45% of patients, respectively. There was poor agreement between revised Schwartz formula and mGFR to diagnose AKI (kappa value of 0.342, p < 0.001; sensitivity of 30%, 95% CI 5; 20%) and ARC (kappa value of 0.342, p < 0.001; sensitivity of 70%, 95% CI 33; 58).

CONCLUSION

In this proof-of-concept study, eGFR formulas were found to be largely inaccurate in the PICU population. Clinicians should therefore use these formulas with caution to guide drug dosing and therapeutic interventions in critically ill children. More research in subgroup populations is warranted to conclude on generalizability of these study findings.

CLINICALTRIALS

gov NCT05179564, registered retrospectively on January 5, 2022.

WHAT IS KNOWN

• Both acute kidney injury and augmented renal clearance may be present in PICU patients and warrant adaptation of therapy, including drug dosing. • Biomarker-based eGFR formulas are widely used for GFR assessment in critically ill children, although endogenous filtration biomarkers have important limitations in PICU patients and eGFR formulas have never been validated against measured GFR in this population.

WHAT IS NEW

• eGFR formulas were found to be largely inaccurate in the PICU population when compared to measured GFR by iohexol clearance. Clinicians should therefore use these formulas with caution to guide drug dosing and therapeutic interventions in critically ill children. • Iohexol plasma clearance could be considered an alternative for accurate GFR assessment in PICU patients.

Derivation and validation of urinary TIMP-1 for the prediction of acute kidney injury and mortality in critically ill children

Background

Acute kidney injury (AKI) is associated with high morbidity and mortality. Multiple urinary biomarkers have been identified to be associated with the prediction of AKI and outcomes. However, the accuracy of these urinary biomarkers for AKI and associated outcomes has not been clearly defined, especially in heterogeneous populations. The aims of the study were to compare the ability of 10 existing or potential urinary biomarkers to predict AKI and pediatric intensive care unit (PICU) mortality and validate urinary tissue inhibitor of metalloproteinases-1 (uTIMP-1) as a better biomarker for early prediction in heterogeneous critically ill children.

Methods

A derivation-validation approach with separate critically ill cohorts was designed. We first conducted a prospective cohort study to determine the ability of 10 urinary biomarkers serially measured in 123 children during the first 7 days of PICU stay to predict AKI and PICU mortality (derivation study) and further validated the better biomarker of uTIMP-1 in a separate cohort of 357 critically ill children (validation study). AKI diagnosis was based on KDIGO classification with serum creatinine and urine output. PICU mortality was defined as all-cause mortality.

Results

In the derivation cohort, 17 of 123 (13.8%) children developed AKI stage 3 or died during the PICU stay, and both the initial and peak uTIMP-1 displayed the highest AUCs of 0.87 (0.79–0.94) and 0.90 (0.84–0.96), respectively, for predicting AKI stage 3 or death. In the validation cohort, 78 of 357 (21.8%) developed AKI during the first week after admission, and 38 (10.6%) died during the PICU stay. The initial uTIMP-1 level was validated to be independently associated with AKI (AOR = 2.88, 95% CI 1.97–4.21), severe AKI (AOR = 2.62, 95% CI 1.78–3.88), AKI stage 3 (AOR = 2.94, 95% CI 1.84–4.68) and PICU mortality (AOR = 1.92, 95% CI 1.11–3.30) after adjustment for potential confounders. The predictive values of uTIMP-1 for AKI, severe AKI, AKI stage 3 and PICU mortality were 0.80 (0.74–0.86), 0.83 (0.77–0.89), 0.84 (0.77–0.92) and 0.83 (0.76–0.89), respectively.

Conclusions

Urinary TIMP-1 levels have been identified and validated to be independently associated with AKI and PICU mortality in independent prospective cohorts and may be an early potential indicator of AKI and PICU mortality in critically ill children.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03302-0.

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.

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.

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.

Acute Kidney Injury in Pediatric Acute Respiratory Distress Syndrome

OBJECTIVES

To describe the incidence of and risk factors for acute kidney injury (AKI) in children with acute respiratory distress syndrome (ARDS) and study the effect of AKI on patient outcomes.

DESIGN

A single-center retrospective study.

SETTING

A tertiary care children's hospital.

PATIENTS

All patients less than 18 years of age who received invasive mechanical ventilation (MV) and developed ARDS between July 2010 and July 2013 were included. Acute kidney injury was defined using p-RIFLE (risk, injury, failure, loss, and end-stage renal disease) criteria.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

One hundred fifteen children met the criteria and were included in the study. Seventy-four children (74/115, 64%) developed AKI. The severity of AKI was risk in 34 (46%) of 74, injury in 19 (26%) of 74, and failure in 21 (28%) of 74. The presence of AKI was associated with lower Pao ₂ to Fio ₂ (P/F) ratio (P = .007), need for inotropes (P = .003), need for diuretics (P = .004), higher oxygenation index (P = .03), higher positive end-expiratory pressure (PEEP; P = .01), higher mean airway pressure (P = .008), and higher Fio ₂ requirement (P = .03). Only PEEP and P/F ratios were significantly associated with AKI in the unadjusted logistic regression model. Patients with AKI had a significantly longer duration of hospital stay, although there was no significant difference in the intensive care unit stay, duration of MV, and mortality. Recovery of AKI occurred in 68% of the patients. A multivariable model including PEEP, P/F ratio, weight, need for inotropes, and need for diuretics had a better receiver operating characteristic (ROC) curve with an AUC of 0.75 compared to the ROC curves for PEEP only and P/F ratio only for the prediction of AKI.

CONCLUSIONS

Patients with ARDS have high rates of AKI, and its presence is associated with increased morbidity and mortality.

Long-term Mortality After Acute Kidney Injury in the Pediatric ICU

OBJECTIVES

(1) To evaluate the association between acute kidney injury (AKI) in the PICU and long-term mortality and (2) to determine the extent to which adding the urine output (UO)-defined AKI alters the association.

METHODS

A 2-center retrospective cohort study of children (≤18 years old) admitted to the PICU between 2003 and 2005 for noncardiac surgery, with follow-up until 2010. Patients with end stage renal disease, no provincial health insurance number, who died during hospitalization, or could not be linked to administrative data were excluded. One hospitalization per patient was included. AKI was defined by using serum creatinine criteria and/or UO criteria. Mortality was ascertained by using administrative data. Cox regression analysis was performed to evaluate the association between AKI and long-term mortality.

RESULTS

The study population included 2041 patients (55.7% male, mean admission age 6.5 ± 5.8 years). Of 2041 hospital survivors, 9 (0.4%) died within 30 days, 51 (2.5%) died within 1 year, and 118 (5.8%) died within 5 to 7 years postdischarge. AKI was independently associated with 5- to 7-year mortality (adjusted hazard ratio [95% confidence interval]: 3.10 [1.46-6.57] and 3.38 [1.63-7.02], respectively). Including UO did not strengthen the association.

CONCLUSIONS

AKI is associated with 5- to 7-year mortality. Because this is an observational study we cannot determine if AKI is causative of mortality or of the pathophysiology. However, patients with AKI represent a high-risk group. It is reasonable that these patients be considered for targeted follow-up until future researchers better elucidate these relationships.

Mortality in adolescents and young adults with chronic diseases during 16 years: a study in a Latin American tertiary hospital

OBJECTIVES

To evaluate mortality in adolescents and young adult patients with chronic diseases followed in a Latin American tertiary hospital.

METHODS

A cross-sectional retrospective study was performed in a tertiary/academic hospital in the state of São Paulo, Brazil. Death occurred in 529/2850 (18.5%) adolescents and young adult patients with chronic diseases, and 25/529 (4.7%) were excluded due to incomplete medical charts. Therefore, 504 deaths were evaluated.

RESULTS

Deaths occurred in 316/504 (63%) of early adolescent patients and in 188/504 (37%) of late adolescent/young adult patients. Further comparisons between early adolescents (n=316) and late adolescent/young adult patients (n=188) with pediatric chronic diseases at the last hospitalization showed that the median disease duration (22.0 [0-173] vs. 43.0 [0-227] months, p<0.001) was significantly lower in early adolescents vs. late adolescent/young adult patients. The median number of previous hospitalizations was significantly lower in the former group (4.0 [1-45] vs. 6.0 [1-52], p<0.001), whereas the last hospitalization in intensive care unit was significantly higher (60% vs. 47%, p=0.003). Regarding supportive measures, palliative care was significantly lower in the younger group compared to the older group (33% vs. 43%, p=0.02). The frequencies of renal replacement therapy (22% vs. 13%, p=0.02), vasoactive agents (65% vs. 54%, p=0.01), and transfusion of blood products (75% vs. 66%, p=0.03) were significantly higher in the younger group. The five most important etiologies of pediatric chronic diseases were: neoplasias (54.2%), hepatic diseases/transplantation (10%), human immunodeficiency virus (5.9%), and childhood-onset systemic lupus erythematosus and juvenile idiopathic arthritis (4.9%). Autopsy was performed in 58/504 (11%), and discordance between clinical and postmortem diagnoses was evidenced in 24/58 (41.3%).

CONCLUSIONS

Almost 20% of deaths occurred in adolescents and young adults with distinct supportive care and severe disease patterns. Discordance between clinical diagnosis and autopsy was frequently observed.

Procalcitonin Value Is an Early Prognostic Factor Related to Mortality in Admission to Pediatric Intensive Care Unit

Introduction

Procalcitonin (PCT) and C-reactive protein (CRP) are already known predictive markers in serious bacterial infections, and it is emphasized that these biomarkers can be used as a marker of increased mortality in critically ill patients. Herein, we aimed to evaluate the initial serum PCT and CRP levels on the outcome of patients in pediatric intensive care units (PICUs) and find out if these biomarkers can be used to predict mortality.

Materials and Methods

The relationship between the initial serum PCT and CRP levels and invasive mechanical ventilation (IMV) and noninvasive mechanical ventilation (NIV) support, inotropic drug need, acute renal kidney injury (AKI), continuous renal replacement therapy (CRRT), mortality, and hospitalization period was investigated retrospectively.

Results

In total, 418 suitable patients (226 males and 192 females) were included in the study. Age distributions of patients ranged from 1 month to 17 years. There was a statistically significant relationship between PCT levels in the first biochemical analysis performed during admission and MV support, inotropic drug use, mortality, ARF, hospitalization in the intensive care unit, CRRT and blood component transfusion. There was a statistically significant relationship between CRP levels and MV support, NIV, inotropic drug use, mortality, AKI, hospitalization in the intensive care unit, CRRT, and blood component transfusion.

Conclusion

We suggest that the initial PCT and CRP levels during admission can be used to predict the outcome of patients in PICU.

Acute Kidney Injury among Hospitalized Children in China

BACKGROUND AND OBJECTIVES

High-quality epidemiologic data on AKI in children are particularly lacking in developing countries. This study aimed to assess the epidemiology and clinical correlates of AKI among hospitalized children in China.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We performed a multicenter study, in a cohort of hospitalized children aged 1 month to 18 years, from 25 general and children's hospitals in China during 2013-2015. We obtained patient-level data from the electronic hospitalization information system and laboratory databases of all children who had at least two serum creatinine tests within any 7-day window during their first 30 days of hospitalization. We identified AKI events according to the creatinine criteria of Kidney Disease Improving Global Outcomes. The in-hospital outcomes of AKI, including mortality, kidney recovery, and length of stay, were assessed. We estimated the corresponding hazard ratios using a Cox proportional hazard model, with adjustment for age, sex, comorbidities, and clinical procedures.

RESULTS

A total of 19,908 (20%) patients with AKI were identified among 101,836 pediatric inpatients, of which 7220 (7%) were community acquired and 12,688 (13%) were hospital acquired. Up to 96% of these AKI events were not diagnosed on the discharge records. The cumulative incidence of AKI in infants (28%) was twice that in adolescents (12%). The profiles of risk factors differed between community-acquired and hospital-acquired AKI and varied with age. Diarrhea and sepsis were the top risk factors for community-acquired AKI, each contributing 6% of the risk. Congenital heart disease/cardiac surgery was the major risk factor for hospital-acquired AKI, contributing to 19% of cases. Exposure to nephrotoxic drugs, mostly nonsteroidal anti-inflammatory drugs and proton pump inhibitors, was common in hospitalized children and was associated with a higher risk of AKI. Death occurred in 842 out of 19,908 patients (4%) with AKI versus 450 out of 81,478 children (0.5%) without AKI. The risk of in-hospital death was higher among children with severe AKI, shock, and respiratory failure. Pediatric AKI was associated with longer hospital stay and higher daily cost, even after adjustment for covariates.

CONCLUSIONS

Pediatric AKI is common and is substantially underdiagnosed in China.

Acute Kidney Injury Epidemiology in pediatrics

We performed a search in the MEDLINE database using the MeSH term: "Acute Kidney Injury", selecting the subtopic "Epidemiology", and applying age and year of publication filters. We also searched for the terms: "acute renal failure" and "epidemiology" "acute tubular necrosis" and "epidemiology" in the title and summary fields with the same filters. In a second search, we searched in the LILACS database, with the terms: "acute renal injury", or "acute renal failure" or "acute kidney injury" and the age filter. All abstracts were evaluated by the authors and the articles considered most relevant, were examined in their entirety. Acute Kidney Injury (AKI) -related mortality ranged from 3-63% in the studies included in this review. AKI etiology has marked regional differences, with sepsis being the main cause in developed countries. In developing countries, primary renal diseases and hypovolemia are still a common cause of AKI.

Acute Kidney Injury in Children With Acute Respiratory Failure

BACKGROUND

Acute kidney injury (AKI) is common in critically ill children and develops in association with organ system dysfunction, with acute respiratory failure (ARF) one of the most common. We aim to study AKI in the pediatric ARF population.

METHODS

Data were retrospectively collected on children aged 1 day to 18 years admitted to the pediatric intensive care unit (PICU) with ARF between 2010 and 2013. Descriptive statistics and multivariate analyses utilizing Mann-Whitney U, Wilcoxon signed rank, χ², or Fisher's exact tests were performed to identify risk factors associated with AKI.

RESULTS

A total of 186 patients, with median age of 36 months (interquartile range 4-120 months) met the inclusion criteria. ARF was related to pulmonary disease in 49%. AKI was noted in 53% of patients. Patients with AKI had significantly higher serum creatinine ( P < .001) and lower estimated creatinine clearance ( P < .001) compared with those without AKI. Among patients with moderate and severe acute respiratory distress syndrome (ARDS), 64% had AKI versus 46% with mild or no ARDS ( P = .02). Patients with AKI had significantly lower PaO₂/FiO₂ ratio ( P = .03), longer PICU ( P = .03), and longer hospital length of stay ( P = .01). ARDS patients were less likely to be AKI free on day 7 of hospitalization, as compared with those without ARDS. Multivariate analysis revealed positive end expiratory pressure (odds ratio [OR] = 1.2, confidence interval [CI] = 1.0-1.4; P = .03) and admission serum creatinine (OR = 27.9, CI = 5.2-148.5; P < .001) to be independently associated with AKI.

CONCLUSIONS

AKI is common in children with ARF. In patients with ARF and AKI, AKI is associated with ARDS and longer PICU and hospital length of stay. Positive end expiratory pressure and serum creatinine are independently associated with AKI.

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

BACKGROUND

Current definitions of AKI do not take into account serum creatinine's high variability in children.

METHODS

We analyzed data from 156,075 hospitalized children with at least two creatinine tests within 30 days. We estimated reference change value (RCV) of creatinine on the basis of age and initial creatinine level in children without kidney disease or known AKI risk, and we used these data to develop a model for detecting pediatric AKI on the basis of RCV of creatinine. We defined pediatric AKI according to pediatric reference change value optimized for AKI in children (pROCK) as creatinine increase beyond RCV of creatinine, which was estimated as the greater of 20 μmol/L or 30% of the initial creatinine level.

RESULTS

Of 102,817 children with at least two serum creatinine tests within 7 days, 5432 (5.3%) had AKI as defined by pROCK compared with 15,647 (15.2%) and 10,446 (10.2%) as defined by pediatric RIFLE (pRIFLE) and Kidney Disease Improving Global Outcomes (KDIGO), respectively. Children with pROCK-defined AKI had significantly increased risk of death (hazard ratio, 3.56; 95% confidence interval, 3.15 to 4.04) compared with those without AKI. About 66% of patients with pRIFLE-defined AKI and 51% of patients with KDIGO-defined AKI, mostly children with initial creatinine level of <30 μmol/L, were reclassified as non-AKI by pROCK, and mortality risk in these children was comparable with risk in those without AKI by all definitions.

CONCLUSIONS

pROCK criterion improves detection of "true" AKI in children compared with earlier definitions that may lead to pediatric AKI overdiagnosis.

Serum and urine FGF23 and IGFBP-7 for the prediction of acute kidney injury in critically ill children

Background

Fibroblast growth factor 23 (FGF23) and insulin-like growth factor binding protein 7 (IGFBP-7) are suggested to be biomarkers for predicting acute kidney injury (AKI). We compared them with proposed AKI biomarker of cystatin C (CysC), and aimed (1) to examine whether concentrations of these biomarkers vary with age, body weight, illness severity assessed by pediatric risk of mortality III score, and kidney function assessed by estimated glomerular filtration rate (eGFR), (2) to determine the association between these biomarkers and AKI, and (3) to evaluate whether these biomarkers could serve as early independent predictors of AKI in critically ill children.

Methods

This prospective single center study included 144 critically ill patients admitted to the pediatric intensive care unit (PICU) regardless of diagnosis. Serum and spot urine samples were collected during the first 24 h after PICU admission. AKI was diagnosed based on the AKI network (AKIN) criteria.

Results

Twenty-one patients developed AKI within 120 h of sample collection, including 11 with severe AKI defined as AKIN stages 2 and 3. Serum FGF23 levels were independently associated with eGFR after adjustment in a multivariate linear analysis (P < 0.001). Urinary IGFBP-7 (Adjusted OR = 2.94 per 1000 ng/mg increase, P = 0.035), serum CysC (Adjusted OR = 5.28, P = 0.005), and urinary CysC (Adjusted OR = 1.13 per 1000 ng/mg increase, P = 0.022) remained significantly associated with severe AKI after adjustment for body weight and illness severity, respectively. Urinary IGFBP-7 level was predictive of severe AKI and achieved the AUC of 0.79 (P = 0.001), but was not better than serum (AUC = 0.89, P < 0.001) and urinary (AUC = 0.88, P < 0.001) CysC in predicting severe AKI.

Conclusions

Serum FGF23 levels were inversely related to measures of eGFR. In contrast to serum and urinary FGF23 which are not associated with AKI in a general and heterogeneous PICU population, an increased urinary IGFBP-7 level was independently associated with the increased risk of severe AKI diagnosed within the next 5 days after sampling, but not superior to serum or urinary CysC in predicting severe AKI in critically ill children.

Healthcare Utilization after Acute Kidney Injury in the Pediatric Intensive Care Unit

BACKGROUND AND OBJECTIVES

Little is known about the long-term burden of AKI in the pediatric intensive care unit. We aim to evaluate if pediatric AKI is associated with higher health service use post-hospital discharge.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This is a retrospective cohort study of children (≤18 years old) admitted to two tertiary centers in Montreal, Canada. Only the first admission per patient was included. AKI was defined in two ways: serum creatinine alone or serum creatinine and/or urine output. The outcomes were 30-day, 1-year, and 5-year hospitalizations, emergency room visits, and physician visits per person-time using provincial administrative data. Univariable and multivariable Poisson regression were used to evaluate AKI associations with outcomes.

RESULTS

A total of 2041 children were included (56% male, mean admission age 6.5±5.8 years); 299 of 1575 (19%) developed AKI defined using serum creatinine alone, and when urine output was included in the AKI definition 355 of 1622 (22%) children developed AKI. AKI defined using serum creatinine alone and AKI defined using serum creatinine and urine output were both associated with higher 1- and 5-year hospitalization risk (AKI by serum creatinine alone adjusted relative risk, 1.42; 95% confidence interval, 1.12 to 1.82; and 1.80; 1.54 to 2.11, respectively [similar when urine output was included]) and higher 5-year physician visits (adjusted relative risk, 1.26; 95% confidence interval, 1.14 to 1.39). AKI was not associated with emergency room use after adjustments.

CONCLUSIONS

AKI is independently associated with higher hospitalizations and physician visits postdischarge.

Quality of life following hospitalization-associated acute kidney injury in children

OBJECTIVES

Acute kidney injury (AKI) is common in hospitalized children. The impact of AKI following hospitalization is not fully understood, particularly the impact on health related quality of life (HRQOL). The goal of this study was to determine the relationship between hospitalization-associated AKI and HRQOL in a pediatric population.

STUDY DESIGN

We conducted a retrospective cohort study of children with hospitalization-associated AKI. Eligible children were 1-19 years old with AKI defined by kidney disease improving global outcomes (KDIGO) criteria and had at least one completed pediatric quality of life (PedsQL) 4.0 Generic Core Scale survey (N = 139). Participants completed up to three surveys to reflect baseline, admission and follow-up status. We categorized children as having mild AKI (KDIGO stage 1, N = 73) or severe AKI (KDIGO stage 2 or 3, N = 66). Mean PedsQL scores were compared by AKI group. Those with both baseline and follow-up surveys were analyzed to determine the proportion who returned to their baseline level of function within 8 weeks of discharge.

RESULTS

Children with mild and severe AKI had similar baseline and admission PedsQL scores. Although children with severe AKI had lower follow-up scores, the results were not statistically significant (78.9 vs. 85.8, p = 0.11). Of those with severe AKI, 48% returned to their baseline level of physical functioning by follow-up, compared to 73% with mild AKI (p = 0.05).

CONCLUSIONS

This is the first study of HRQOL following hospitalization-associated AKI. We found that children with severe AKI had depressed physical functioning after discharge when compared to children with mild AKI.

Evaluation of height-dependent and height-independent methods of estimating baseline serum creatinine in critically ill children

BACKGROUND

Baseline serum creatinine (bSCr) is required for diagnosing acute kidney injury (AKI). In children, bSCr is commonly defined as the lowest measurement within 3 months of admission. Measured values are often missing and estimating bSCr using height-based glomerular filtration rate (GFR) equations is problematic when height is unavailable.

METHODS

This is a retrospective cohort study including 538 children admitted to the intensive care unit (ICU) between 2003 and 2005 at two centers in Canada, with measured bSCr, height, and ICU-SCr values. We evaluated the bias, accuracy, and precision of back-calculating bSCr from height-dependent and height-independent GFR equations. Agreement of AKI defined using measured and estimated bSCr was calculated. Multivariate analyses were performed to assess the impact of bSCr estimation methods on the association between AKI and ICU mortality, length of stay, and duration of mechanical ventilation.

RESULTS

Both methods underestimated bSCr by 1-3%, showed good accuracy (∼30% of patients with estimated bSCr within 10% of measured bSCr), but poor precision (wide 95% limits of agreement). The agreement between AKI defined by estimated versus measured bSCr was >80% (κ >0.5). The height-independent method performed best in children >13 years old; however, overall, both methods performed similarly across age subgroups. AKI was associated with longer stay, prolonged mechanical ventilation, and ICU mortality using measured and estimated bSCr.

CONCLUSIONS

Height-dependent and height-independent bSCr estimation methods were comparable. This may have significant implications for performing pediatric AKI research using large databases, and in clinical care to define AKI when height is unknown.

Incidence and outcome of acute kidney injury by the pRIFLE criteria for children receiving extracorporeal membrane oxygenation after heart surgery

BACKGROUND

Acute kidney injury (AKI) is common in patients treated with extracorporeal membrane oxygenation (ECMO). The RIFLE criteria demonstrate clinical relevance for diagnosing AKI and classifying its severity.

OBJECTIVES

To systematically define the incidence, clinical course and outcome of AKI using the pediatric pRIFLE criteria.

DESIGN

Retrospective, medical records review.

SETTINGS

Pediatric cardiac surgical intensive care units at a tertiary care hospital in Riyadh.

PATIENTS AND METHODS

We reviewed the records of all pediatric patients that underwent cardiac surgery and required ECMO postoperatively between 1 January 2011 and 1 January 2016. AKI was classified according to the pRIFLE criteria 48 hours after ECMO initiation. Demographics and concomitant therapies for all patients were collected.

MAIN OUTCOME MEASURE(S)

Outcome was assessed by recovery from AKI at time of discharge, ICU stay and mortality.

RESULTS

Fifty-nine patients needed ECMO after cardiac surgery during the study period. Their mean (SD) age and weight was 11.0 (16.5) month and 5.5 (3.6) kg, respectively. All patients had a central venoarterial ECMO inserted. Fifty-three patients (90%) developed AKI after ECMO initiation. The majority of patients (57%) were categorized as pRIFLE-Failure, having a higher mortality rate (28/34 patients, 82%) in comparison to the pRIFLE-Injury and pRIFLE-Risk groups. Twenty-nine patients (49%) required either peritoneal dialysis (PD), or renal replacement therapy (RRT) or both. For AKI vs non-AKI patients, there was a statistically significant difference between mean (SD) ECMO duration (9.0 [8.00] vs 6.0 [2.0] days; P=.02) and ICU stay (37.0 [41.0] vs 21.0 [5.0] days; P=.03), respectively. The overall mortality rate was 58%, with a significant difference (P=.03) between AKI and non-AKI groups. All the patients who survived had normal creatinine clearance at hospital discharge.

CONCLUSION

There is a high incidence of AKI in pediatric patients requiring ECMO after cardiac surgery, and it is associated with higher mortality, increased ECMO duration, and increased ventilator days.

LIMITATIONS

Single-center retrospective analysis and the small sample size limited the precision of our estimates in sub-populations.