Severe Acute Kidney Injury and Mortality in Extremely Low Gestational Age Neonates

Incidence of acute kidney injury-associated mortality in hospitalized children: a systematic review and meta-analysis

BACKGROUND

Acute kidney injury (AKI) is a significant health concern in hospitalized children and is associated with increased mortality. However, the true burden of AKI-associated mortality in pediatric populations remains unclear.

OBJECTIVE

To determine the pooled incidence of mortality independently associated with AKI in hospitalized children globally.

DATA SOURCES

Medline and Embase were searched for studies published by March 2024.

STUDY ELIGIBILITY CRITERIA

The inclusion criteria encompassed observational studies involving hospitalized pediatric patients (< 18 years old) with AKI. Only studies that identified AKI as an independent risk factor for increased mortality in multivariate analysis were considered.

STUDY APPRAISAL AND SYNTHESIS METHODS

Studies with at least 100 AKI patients were included in the meta-analysis. Two authors extracted data on the study and patients' characteristics and mortality across AKI stages and assessed the risk of bias. We used a random-effects meta-analysis to generate pooled estimates of mortality.

RESULTS

Analysis of 60 studies including 133,876 children with AKI revealed a pooled in-hospital mortality rate of 18.27% (95% CI: 14.89, 21.65). Mortality increased with AKI severity; 8.19% in stage 1, 13.44% in stage 2, and 27.78% in stage 3. Subgroup analyses showed no significant differences across geographical regions, income levels, or AKI definition criteria. The pooled post-discharge mortality rate was 6.84% (95% CI: 5.86, 7.82) in a 1-9-year follow-up period.

CONCLUSIONS

This meta-analysis demonstrates a substantial global burden of AKI-associated mortality in hospitalized children, with higher mortality rates in more severe AKI stages. These findings highlight the critical need for early detection and intervention strategies in pediatric AKI management.

CLINICAL TRIAL NUMBER

Not applicable.

Attenuation of acute kidney injury in a murine model of neonatal Escherichia coli sepsis

Introduction

Sepsis is a risk factor for acute kidney injury (AKI) in neonates, for which no effective treatment exists. The phosphodiesterase inhibitor pentoxifylline (PTX) has demonstrated renal protection from ischemia and inflammation in adult rodents. We hypothesized that addition of PTX to antibiotics may attenuate immune and histological AKI in a murine neonatal sepsis model.

Methods

Postnatal (PN) day 1 C57BL/6J mice were injected with E. coli K1 strain at 105 colony forming units per gram weight or saline control. After 1.5 hours, septic pups randomly received saline, gentamicin or cefotaxime, with/without PTX. 5.5h after sepsis initiation, kidneys and blood were harvested for measurements of biomarkers of inflammation and kidney injury. Renal sections from PN7 mice were used for histology and immunofluorescence. Linear mixed effect models were employed to fit the outcomes including interaction between treatment group and sex.

Results

Septic mice demonstrated robust expression of pro-inflammatory cytokines, chemokines and biomarkers of tubular injury in renal tissue, which were attenuated in response to combined PTX and antibiotics (gentamicin or cefotaxime): chemokines (p<0.001), plasma (p<0.01) and tissue IL-6 (p<0.05), plasma TNF (p<0.001), NGAL (p<0.01), CXCL10 (p<0.01), osteopontin (p<0.05), and VEGF (p<0.05), with a trend for KIM-1 (tissue concentration: p=0.21, fluorescence area: p=0.12). Interactions between treatment and sex were present for several cytokines and kidney injury biomarkers. Immunofluorescence findings for the tubular injury markers (NGAL and KIM-1) were consistent with biomarker expression in tissue lysates.

Conclusion

Neonatal E. coli sepsis leads to increased expression of renal tissue inflammation and injury biomarkers consistent with AKI, which may be attenuated with PTX combined with antibiotic treatment.

ADVANCE: a biomedical informatics approach to investigate acute kidney injury in infants

BACKGROUND

Acute kidney injury (AKI) occurs in up to half of infants admitted to the neonatal intensive care unit (NICU) and is associated with increased risks of death and more days of mechanical ventilation, hospitalization, and vasopressor drug support. Our objective was to build a granular relational database to study the impact that AKI has on infants admitted to Level-IV NICUs.

METHODS

A relational database was created by linking data from the Children's Hospitals Neonatal Database with AKI-focused data from electronic health records from 9 centers.

RESULTS

The current cohort consists of 24,870 infants with a median (IQR) gestational age of birth of 37 weeks (32 weeks, 39 weeks), and a median birth weight of 2.720 kg (1.750 kg, 3.310 kg). There was a male predominance with 14,214 (57%) males. In all, 2434 (9.8%) of the mothers were of Hispanic ethnicity. The maternal race breakdown of the cohort was as follows: 741 (3.0%) Asian, 5911 (24%) Black, and 14,945 (60%) White. Overall mortality was 5.8%.

CONCLUSION

The ADVANCE relational database is an innovative research tool to rigorously study the epidemiology of AKI in a large national cohort of infants admitted to Level-IV NICUs involved in the Children's Hospital Neonatal Consortium.

IMPACT

We used a biomedical informatics approach to build a relational database to study acute kidney injury in infants. We highlight our methodology linking Children's Hospital Neonatal Consortium and electronic health record data from nine neonatal intensive care units. The ADVANCE relational database is a granular and innovative research tool to study risk factors and in-hospital outcomes of acute kidney injury and mortality in a vulnerable patient population.

Association of delayed cord clamping with acute kidney injury and two-year kidney outcomes in extremely premature neonates: a secondary analysis of the preterm erythropoietin neuroprotection trial (PENUT)

BACKGROUND

Delayed cord clamping (DCC) occurs in most preterm births.

OBJECTIVE

Evaluate the association of DCC with acute kidney injury (AKI) and two-year kidney outcomes.

METHODS

Secondary analysis of the Preterm Erythropoietin Neuroprotection Trial of neonates born 240/7 to 276/7 weeks gestation. AKI and two year kidney outcomes were compared in neonates with DCC ( ≥ 30 s after delivery) to those with early cord clamping (ECC) (<30 s after delivery).

RESULTS

The incidence and severity of AKI did not differ between the DCC and ECC groups (aOR 1.17 [95%CI 0.76-1.80]). At two years corrected age, DCC was associated with a 4.5-fold increased adjusted odds of estimated glomerular filtration rate (eGFR) <90 mL/min/1.73m2. No significant associations were noted between DCC and albuminuria or elevated blood pressure.

CONCLUSIONS

DCC was not associated with decreased neonatal AKI, but was associated with higher adjusted odds of eGFR <90 mL/min/1.73m2 at two years.

Urinary Output of Very Low Birth Weight Infants during the First Weeks of Life

INTRODUCTION

Daily urinary output (UOP) serves as important tool to identify acute kidney injury (AKI) in preterm infants. However, reference values for UOP, especially stratified for gestational age (GA), are missing.

METHODS

This retrospective single-center study assessed UOP during the first 28 days of life in 128 very low birth weight (VLBW) infants.

RESULTS

VLBW infants exhibit a highly dynamic daily UOP profile in the first 28 days of life with a maximum at day 12 with 4.78 mL/kg bodyweight/h. In the subcohort of 64 extremely low gestational age neonates (ELGANs), the highest UOP is measured during the second week of life. Infants born before 24 weeks of gestation have significantly higher UOP than more mature infants.

CONCLUSION

UOP is dynamic in the postnatal period and differs significantly between GA cohorts in the subgroup of ELGANs. These data might point to an adaption of the UOP threshold for neonatal AKI in preterm infants.

Erythropoiesis-stimulating agents for preventing acute kidney injury

BACKGROUND

Acute kidney injury (AKI) is characterised by a rapid decline in kidney function and is caused by a variety of clinical conditions. The incidence of AKI in hospitalised adults is high. In animal studies, erythropoiesis-stimulating agents (ESA) have been shown to act as a novel nephroprotective agent against ischaemic, toxic, and septic AKI by inhibiting apoptosis, promoting cell proliferation, and inducing antioxidant and anti-inflammatory responses. As a result, ESAs may reduce the incidence of AKI in humans. Randomised controlled trials (RCTs) have been conducted on the efficacy and safety of ESAs, but no prior systematic reviews exist that comprehensively examine ESAs with respect to AKI prevention, although the effectiveness of these agents has been examined for a range of other diseases and clinical situations.

OBJECTIVES

This review aimed to look at the benefits and harms of ESAs for preventing AKI in the context of any health condition.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 30 August 2024 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

We included RCTs and quasi-RCTs (in which allocation to treatment was based on alternate assignment or order of medical records, admission dates, date of birth or other non-random methods) that compared ESAs with placebo or standard care in people at risk of AKI.

DATA COLLECTION AND ANALYSIS

Three authors independently extracted data and assessed the risk of bias for included studies. We used random-effects model meta-analyses to perform quantitative synthesis of the data. We used the I2 statistic to measure heterogeneity amongst the studies in each analysis. We indicated summary estimates as a risk ratio (RR) for dichotomous outcomes and mean difference (MD) for continuous outcomes with their 95% confidence interval (CI). We assessed the certainty of the evidence for each main outcome using the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) approach.

MAIN RESULTS

A total of 20 studies (36 records, 5348 participants) were included. The number of participants ranged from 10 to 1302, and most studies were carried out in single centres (13/20). All the included studies compared ESAs to placebo or usual care. Many of the studies were judged to have unclear or high risk of reporting bias, but were at low risk for other types of bias. ESAs, when compared to control interventions, probably makes little or no difference to the risk of AKI (18 studies, 5314 participants: RR 0.97, 95% CI 0.85 to 1.10; I² = 19%; moderate-certainty evidence), or death (18 studies, 5263 participants: RR 0.92, 95% CI 0.80 to 1.06; I² = 0%; moderate-certainty evidence), and may make little or no difference to the initiation of dialysis (14 studies, 2059 participants: RR 1.16, 95% CI 0.90 to 1.51; I² = 0%; low-certainty evidence). Even with standardised measurement of AKI, the studies showed no difference in results between different routes of administration (subcutaneous or intravenous), background diseases (cardiac surgeries, children or neonates, other adults at risk of AKI), or duration or dose of ESA. ESAs may make little or no difference to the risk of thrombosis when compared to control interventions (8 studies, 3484 participants: RR 0.92, 95% CI 0.68 to 1.24; I² = 0%). Similarly, ESAs may have little or no effect on kidney function measures and adverse events such as myocardial infarction, stroke or hypertension. However, this may be due to the low incidence of these adverse events.

AUTHORS' CONCLUSIONS

In patients at risk of AKI, ESAs probably do not reduce the risk of AKI or death and may not reduce the need for starting dialysis. Similarly, there may be no differences in kidney function measures and adverse events such as thrombosis, myocardial infarction, stroke or hypertension. There are currently two ongoing studies that have either not been completed or published, and it is unclear whether they will change the results. Caution should be exercised when using ESAs to prevent AKI.

Association of delayed cord clamping with acute kidney injury and two-year kidney outcomes in extremely premature neonates: a secondary analysis of the Preterm Erythropoietin Neuroprotection Trial (PENUT)

Background

Delayed cord clamping (DCC) occurs in most preterm births.

Objective

Evaluate the association of DCC with acute kidney injury (AKI) and two-year kidney outcomes.

Methods

Secondary analysis of the Preterm Erythropoietin Neuroprotection Trial of neonates born 240/7 to 276/7 weeks' gestation. AKI and two year kidney outcomes were compared in neonates with DCC (≥30 seconds after delivery) to those with early cord clamping (ECC) (<30 seconds after delivery).

Results

The incidence and severity of AKI did not differ between the DCC and ECC groups (aOR 1.17 [95%CI 0.76-1.80]). At two years corrected age, DCC was associated with a 4.5-fold times increased adjusted odds of eGFR <90 mL/min/1.73m2. No significant associations were noted between DCC and albuminuria or elevated BP.

Conclusions

DCC was not associated with decreased neonatal AKI, but was associated with higher adjusted odds of eGFR <90 mL/min/1.73m2 at two years.

Impact of severe acute kidney injury on short-term mortality in urosepsis

PURPOSE

To evaluate the impact of severe acute kidney injury (AKI) on short-term mortality in patients with urosepsis.

METHODS

This prospective cohort study evaluated 207 patients with urosepsis. AKI was diagnosed in accordance with the Kidney Disease Improving Global Outcomes criteria, and severe AKI was defined as stage 2 or 3 AKI. Patients were divided into two groups: patients who developed severe AKI (severe AKI group) and patients who did not (control group). The primary endpoint was all-cause mortality within 30 days. The secondary endpoints were 90-day mortality and in-hospital mortality. The exploratory outcomes were the risk factors for severe AKI development.

RESULTS

The median patient age was 79 years. Of the 207 patients, 56 (27%) developed severe AKI. The 30-day mortality rate in the severe AKI group was significantly higher than that in the control group (20% vs. 2.0%, respectively; P < 0.001). In the multivariable analysis, performance status and severe AKI were significantly associated with 30-day mortality. The in-hospital mortality and 90-day mortality rates in the severe AKI group were significantly higher than those in the control group (P < 0.001 and P < 0.001, respectively). In the multivariable analysis, age, urolithiasis-related sepsis, lactate values, and disseminated intravascular coagulation were significantly associated with severe AKI development.

CONCLUSIONS

Severe AKI was a common complication in patients with urosepsis and contributed to high short-term mortality rates.

Low incidence of acute kidney injury in VLBW infants with restrictive use of mechanical ventilation

BACKGROUND

We assessed the incidence of and risk factors for acute kidney injury (AKI) in very low birthweight infants (VLBW) in a center with a specific neonatal management protocol focusing on avoidance of early mechanical ventilation (MV).

METHODS

This retrospective single center analysis includes 128 infants born in 2020 with a gestational age ≥ 22 weeks who were screened for AKI using the nKDIGO criteria.

RESULTS

AKI was identified in 25/128 patients (19.5%) with eight of them (6.3%) presenting with severe AKI. Low gestational age, birthweight and 10-minute Apgar score as well as high CRIB-1 score were all associated with incidence of AKI. Forty-five percent of the infants with MV developed AKI vs. 8.9% of those without MV (p < 0.001). Early onset of MV and administration of more than 3 dosages of NSAIDs for patent duct were identified as independent risk factors for AKI in a logistic regression analysis.

CONCLUSIONS

We report a substantially lower frequency of AKI in VLBW infants as compared to previous studies, along with a very low rate of MV. A neonatal protocol focusing on avoidance of MV within the first days of life may be a key factor to decrease the risk of AKI in immature infants.

Impact of preterm birth on kidney health and development

Preterm birth, defined as birth before the gestational age of 37 weeks, affects 11% of the newborns worldwide. While extensive research has focused on the immediate complications associated with prematurity, emerging evidence suggests a link between prematurity and the development of kidney disease later in life. It has been demonstrated that the normal course of kidney development is interrupted in infants born prematurely, causing an overall decrease in functional nephrons. Yet, the pathogenesis leading to the alterations in kidney development and the subsequent pathophysiological consequences causing kidney disease on the long-term are incompletely understood. In the present review, we discuss the current knowledge on nephrogenesis and how this process is affected in prematurity. We further discuss the epidemiological evidence and experimental data demonstrating the increased risk of kidney disease in these individuals and highlight important knowledge gaps. Importantly, understanding the intricate interplay between prematurity, abnormal kidney development, and the long-term risk of kidney disease is crucial for implementing effective preventive and therapeutic strategies.

Incidence, Risk Factors, and Outcomes Associated With Recurrent Neonatal Acute Kidney Injury in the AWAKEN Study

Importance

The incidence and associated outcomes of recurrent acute kidney injury (rAKI) in neonates remain largely unknown.

Objective

To determine the incidence, risk factors, and clinical outcomes associated with rAKI in critically ill neonates.

Design, Setting, and Participants

This cohort study was a secondary analysis of the multicenter, international Assessment of Worldwide Acute Kidney Injury Epidemiology in Neonates retrospective study. Comparisons were made among neonates with no AKI, a single AKI episode (sAKI), and rAKI. All neonates younger than 14 days who were admitted between January 1 and March 31, 2014, to 24 participating level II to IV neonatal intensive care units and received intravenous fluids for at least 48 hours were considered for inclusion. Neonates with congenital heart disease requiring surgery within the first week of life, lethal chromosomal anomalies, death within 48 hours of admission, or severe congenital kidney abnormalities were excluded. Data were analyzed from May 23, 2022, to December 8, 2023.

Exposure

Recurrent AKI using the neonatal Kidney Disease: Improving Global Outcomes criteria. Determination of each rAKI required a complete return to the baseline serum creatinine level that defined the prior AKI episode.

Main Outcomes and Measures

Incidence and risk factors of rAKI and associations of rAKI with length of stay (LOS; ie, birth to hospital discharge) and mortality.

Results

The study cohort (n = 2162) included 1233 male neonates (57.0%). Gestational age distribution was less than 29 weeks for 276 neonates (12.8%), 29 to less than 36 weeks for 958 (44.3%), and 36 weeks or older for 928 (42.9%). Of 605 neonates with AKI, 133 (22.0%) developed rAKI with risk factors including younger gestational age, lower birthweight, and higher stage of initial AKI. Infants with rAKI experienced longer median LOS (no AKI, 17 [IQR, 8-34] days; sAKI, 18 [IQR, 9-45] days; rAKI, 60 [IQR, 25-109] days; P < .001). Time-varying Cox proportional hazards regression models suggest rAKI is independently associated with a lower hazard of discharge (adjusted hazard ratio, 0.7 [95% CI, 0.6-0.9]; P = .01) when compared with sAKI, but mortality did not differ between groups (adjusted hazard ratio, 1.4 [95% CI, 0.6-3.0]; P = .44).

Conclusions and Relevance

In this cohort study, neonatal rAKI was independently associated with longer LOS when compared with sAKI, suggesting that rAKI in neonates may be an important clinical distinction warranting further study and careful monitoring after an initial AKI episode.

Real-life effects, complications, and outcomes in 39 critically ill neonates receiving continuous kidney replacement therapy

BACKGROUND

Continuous kidney replacement therapy (CKRT) has been expanded from simple kidney replacement therapy to the field of critical illness in children. However, CKRT is rarely used in critically ill neonates in the neonatal intensive care unit (NICU). This study aimed to describe patients' clinical characteristics at admission and CKRT initiation, CKRT effects, short-term outcomes, and predictors of death in critically ill neonates.

METHODS

A 7-year single-center retrospective study in a tertiary NICU.

RESULTS

Thirty-nine critically ill neonates received CKRT between May 2015 and April 2022 with a mortality rate of 35.9%. The most common primary diagnosis was neonatal sepsis in 15 cases (38.5%). Continuous veno-venous hemodiafiltration and continuous veno-venous hemofiltration were applied in 43.6% and 56.4% of neonates, respectively. The duration of CKRT was 44 (18, 72) h. Thirty-one patients (79.5%) had complications due to CKRT-related adverse events, and the most common complication was thrombocytopenia. Approximately 12 h after the CKRT initiation, urine volume, mean arterial pressure, and pH were increased, and serum creatinine, blood urea nitrogen, and blood lactate were decreased. In the multivariate logistic regression analysis, neonatal critical illness score [odds ratio 0.886 (0.786 ~ 0.998), P = 0.046] was an independent risk factor for death in critically ill neonates who received CKRT.

CONCLUSIONS

CKRT can be an effective and feasible technique in critically ill neonates, but the overall mortality and CKRT-related complications are relatively high. Furthermore, the probability of death is greater among neonates with greater severity of illness at CKRT initiation. A higher resolution version of the Graphical abstract is available as Supplementary information.

Neurodevelopment After Neonatal Acute Kidney Injury in Very Preterm-Birth Children

Introduction

This study aimed to assess head circumference (HC) growth and neurodevelopmental outcomes in very preterm-birth children after neonatal acute kidney injury (AKI).

Methods

This longitudinal follow-up cohort included 732 very preterm neonates of gestational age <31 weeks admitted to a tertiary center between 2008 and 2020. AKI was categorized as nonoliguric and oliguric AKI based on the urine output criteria during admission. We compared the differences in death, z scores of HC (zHC) at term-equivalent age (TEA) and at corrected ages of 6, 12, and 24 months, and the neurodevelopmental outcomes at corrected age of 24 months after neonatal nonoliguric and oliguric AKI.

Results

Among the 154 neonates who developed AKI, 72 had oliguric AKI and 82 had nonoliguric AKI. At TEA, oliguric AKI, but not nonoliguric AKI, was independently associated with lower zHC than non-AKI (mean differences, -0.49; 95% confidence interval [CI], -0.92 to -0.06). Although the 3 groups were comparable in zHC at corrected ages of 6, 12, and 24 months, the oliguric AKI group, but not the nonoliguric AKI group, had a higher rate of microcephaly by corrected age of 24 months. In addition, the oliguric AKI group, but not the nonoliguric AKI group, was more likely to die (61% vs. 9%) and have neurodevelopmental impairment (41% vs. 14%) compare with the non-AKI group. After adjustment, oliguric (adjusted odds ratio [aOR], 8.97; 95% CI, 2.19-36.76), but not nonoliguric, AKI was associated with neurodevelopmental impairment.

Conclusion

Neonatal oliguric AKI is associated with neurodevelopmental impairment in very preterm-birth children. Long-term head-size and neurodevelopmental follow-up after neonatal AKI is warranted.

Neonatal nephrotoxic medication exposure and early acute kidney injury: results from the AWAKEN study

BACKGROUND

We aimed to describe nephrotoxic medication exposure and investigate associations between exposure and acute kidney injury (AKI) in the neonatal intensive care unit during the first postnatal week.

DESIGN/METHODS

Secondary analysis of the AWAKEN cohort. We evaluated nephrotoxic medication exposure during the first postnatal week and associations with AKI using time-varying Cox proportional hazard regressions models. Nephrotoxic medication exposure categories were defined as: no nephrotoxic medication, nephrotoxic medications excluding aminoglycosides, aminoglycoside alone, and aminoglycoside and another nephrotoxic medication.

RESULTS

Of 2162 neonates, 1616 (74.7%) received ≥1 nephrotoxic medication. Aminoglycoside receipt was most common (72%). AKI developed in 211(9.8%) neonates and was associated with a nephrotoxic medication exposure (p < 0.01). Nephrotoxic medication exposures including a nephrotoxic medication excluding aminoglycoside (aHR 3.14, 95% CI 1.31-7.55) and aminoglycoside and  another nephrotoxic medication (aHR 4.79, 95% CI 2.19-10.50) were independently associated with AKI and severe AKI (stage 2/3), respectively.

CONCLUSIONS

Nephrotoxic medication exposure in critically ill infants is common during the first postnatal week. Specific nephrotoxic medication exposure, principally aminoglycosides with another nephrotoxic medication, are independently associated with early AKI.

Effects of melatonin against acute kidney injury: A systematic review and meta-analysis

INTRODUCTION

Melatonin is a hormone synthesized by the pineal gland, and has antioxidative effects in reducing acute kidney injury (AKI). In the past three years, an increasing number of studies have evaluated whether melatonin has a protective effect on AKI. The study systematically reviewed and assessed the efficacy and safety of melatonin in preventing AKI.

MATERIAL AND METHODS

A systematic literature search was conducted in the PubMed, Embase, and Web of Science databases on February 15, 2023. Eligible records were screened according to the inclusion and exclusion criteria. The odds ratio and Hedges' gwith the corresponding 95% confidence intervals were selected to evaluate the effects of melatonin on AKI. We pooled extracted data using a fixed- or random-effects model based on a heterogeneity test.

RESULTS

There were five studies (one cohort study and four randomized controlled trials) included in the meta-analysis. Although the glomerular filtration rate (GFR) may be significantly improved by melatonin, the incidence of AKI was not significantly decreased in the melatonin group compared with the control group in randomized controlled trials (RCTs).

CONCLUSIONS

In our study, the present results do not support a direct effect of melatonin use on the reduction of AKI. More well-designed clinical studies with larger sample size are required in the future.

Urine acute kidney injury biomarkers in extremely low gestational age neonates: a nested case control study of 21 candidate urine biomarkers

BACKGROUND

Acute kidney injury (AKI) is common and is associated with poor clinical outcomes in premature neonates. Urine biomarkers hold the promise to improve our understanding and care of patients with kidney disease. Because kidney maturation and gender can impact urine biomarker values in extremely low gestational age neonates (ELGANs), careful control of gestational age (GA) and time is critical to any urine biomarker studies in neonates.

METHODS

To improve our understanding of the potential use of urine biomarkers to detect AKI during the first postnatal weeks, we performed a nested case-control study to evaluate 21 candidate urine AKI biomarkers. Cases include 20 ELGANs with severe AKI. Each case was matched with 2 controls for the same GA week (rounded down to the nearest week), gender, and birth weight (BW) (± 50 g).

RESULTS

Urine cystatin C, creatinine, ghrelin, fibroblast growth factor-23 (FGF23), tissue metalloproteinase 2 (TIMP2) and vascular endothelial growth factor A (VEGFa) concentrations were higher in ELGANs with early severe AKI compared to matched control subjects without AKI. Urine epidermal growth factor (EGF) and uromodulin (UMOD) concentrations are lower in cases than controls. Interleukin (IL)-15 was lower on day 1, but higher on day 8 in cases than controls; while VEGFa was lower on day 1, but higher on day 5 in cases than controls.

CONCLUSION

Urine biomarkers hold the promise to improve our ability to reliably detect kidney injury. Interventional studies are needed to determine the biomarkers' ability to predict outcomes, enhance AKI phenotypes, and improve timely interventions which can prevent the sequalae of AKI in ELGANs. A higher resolution version of the Graphical abstract is available as Supplementary information.

Acute Kidney Injury in Very Low Birth Weight Infants: A Major Morbidity and Mortality Risk Factor

BACKGROUND AND OBJECTIVES

Very low birth weight (VLBW) infants are at high risk of developing acute kidney injury (AKI), presumably secondary to low kidney reserves, stressful postnatal events, and drug exposures. Our study aimed to identify the prevalence, risk factors, and outcomes associated with AKI in VLBW infants.

STUDY DESIGN

Records of all VLBW infants admitted to two medical campuses between January 2019 and June 2020 were retrospectively reviewed. AKI was classified using the modified KDIGO definition to include only serum creatinine. Risk factors and composite outcomes were compared between infants with and without AKI. We evaluated the main predictors of AKI and death with forward stepwise regression analysis.

RESULTS

152 VLBW infants were enrolled. 21% of them developed AKI. Based on the multivariable analysis, the most significant predictors of AKI were the use of vasopressors, patent ductus arteriosus, and bloodstream infection. AKI had a strong and independent association with neonatal mortality.

CONCLUSIONS

AKI is common in VLBW infants and is a significant risk factor for mortality. Efforts to prevent AKI are necessary to prevent its harmful effects.

Early detection of acute kidney injury in preterm newborns with perinatal asphyxia using serum cystatin

Introduction:The diagnosis of acute kidney injury (AKI) in preterm newborns with perinatal asphyxia based on increased serum creatinine (sCr) value and oliguria/anuria is usually delayed. The Aim of this paper is to evaluate serum cystatin C as an early predictor of AKI. Materials and methods:The study included 42 preterm newborns (24-37 weeks) with perinatal asphyxia (Apgar score (AS) ≤ 3 at 5 minutes of life or blood pH on admission ≤ 7.00). The sCr and sCysC levels were measured on the 1st, 3rd, and 7th day of life. According to KDIGO criteria, the newborns were classified into groups, and sCr and sCys-C values were compared. Results:The mean gestational age was 29.9 ± 3.0 weeks. AKI was diagnosed in 62.8 % of patients. Of these patients, 81.5% belonged to AKI 1 group, and 18.5 % to AKI 2 group.No newborns had the criteria for AKI 3. On day 7 the mean sCr values were significantly higher in AKI (65.4± 21.8) compared with the non-AKI group (168.4±38.2) (p<0.001), but not on day 1 and 3 (p = 0.322, 0.012, respectively). The sCys-C values were significantly higher in the AKI group on day 3 ( AKI vs. non-AKI group, 0.69 ±0.22 vs. 1.22 ±0.20; p <0.001) and day 7 (AKI vs. non-AKI group, 0.62 ±0.41 vs. 1.68 ±0.20; p <0.001). The sCys-C was also an earlier marker of a more severe stage of AKI than sCr. Conclusion:The sCys-C was elevated earlier than sCr, making it a valuable diagnostic tool for AKI in preterm newborns.

Frequency of Acute Kidney Injury and Association With Mortality Among Extremely Preterm Infants

IMPORTANCE

Neonatal acute kidney injury (AKI) is common and associated with morbidity and mortality. The temporal relationship between AKI and critical illness, as well as the frequency of AKI definition components (urine output and serum creatinine [sCr] concentration change), are unknown in extremely low-birth-weight (ELBW) (<1000 g), extremely preterm (<29 weeks' completed gestational age [GA]) infants.

OBJECTIVE

To measure the frequency of AKI from birth to death or discharge with attention to the definition components as well as the temporal relationship of AKI to critical illness and death.

DESIGN, SETTING, AND PARTICIPANTS

A single-center, multiyear, retrospective cohort study was conducted at an academic level IV neonatal intensive care unit between January 1, 2012, and January 1, 2020. Participants included inborn ELBW and infants at 22 to 28 weeks' completed GA with confirmed congenital anomalies who survived 12 hours or more.

EXPOSURES

Extremely preterm birth and ELBW.

MAIN OUTCOMES AND MEASURES

The primary outcome was AKI frequency. The timing, severity, and criteria for AKI were measured. The temporal relationship between AKI, organ dysfunction, and outcomes were quantified using odds ratios (ORs), logistic regression, and Shapley Additive Explanations. Acute kidney injury recognition, imaging, pediatric nephrology consultation, and follow-up were determined.

RESULTS

A total of 436 infants (52% male; 44% Black) met the inclusion criteria (median BW, 725 g; median GA, 25.7 wk). Acute kidney injury was common in the first week of life (44%), primarily based on the change in the sCr concentration criterion (88%), and negatively associated with GA (OR, 0.69; 95% CI, 0.60-0.78), but positively associated with antecedent critical illness (OR, 1.17; 95% CI, 1.12-1.23), severe intraventricular hemorrhage (OR, 1.86; 95% CI, 1.12-3.08), late-onset sepsis (OR, 1.03; 95% CI, 1.02-1.03), and mortality (OR, 2.77; 95% CI, 1.63-4.72). Acute kidney injury had negligible clinical contribution to death within the model (Shapley Additive Explanation, <0.5% change to outcome) relative to antecedent patient-concentration organ dysfunction (6%-15% change). Among infants with severe AKI, recognition (32%), nephrology inpatient consultation (16%), and outpatient follow-up (9%) were not common.

CONCLUSIONS AND RELEVANCE

In this cohort study of ELBW infants, AKI was common in the first week of life, inversely associated with GA, and followed organ (primarily cardiovascular) dysfunction. Acute kidney injury considered as the primary pathway to mortality was rare, and amelioration of AKI to modify death was not well supported.

Neonatal Acute Kidney Injury

Acute kidney injury (AKI) is a common occurrence in the neonatal intensive care unit (NICU). In recent years, our knowledge of the incidence and impact of neonatal AKI on outcomes has expanded exponentially. Neonatal AKI has been shown to be associated with adverse outcomes including increased length of mechanical ventilation, prolonged length of stay, and rise in mortality. There has also been increasing work suggesting that neonates with AKI are at higher risk of chronic kidney disease (CKD). In the past, AKI had been defined multiple ways. The utilization of the neonatal modified Kidney Disease: Improving Global Outcomes (KDIGO) criteria as the standard definition for neonatal AKI in research and clinical care has driven the advances in our understanding of neonatal AKI over the last 10 years. This definition has allowed researchers and clinicians to better understand the incidence, risk factors, and outcomes associated with neonatal AKI across populations through a multitude of single-center studies and the seminal, multicenter Assessment of Worldwide Acute Kidney Injury Epidemiology in Neonates (AWAKEN) study. As the impacts of neonatal AKI have become clear, a shift in efforts toward identifying those at highest risk, protocolizing AKI surveillance, improving prevention and diagnosis, and expanding kidney support therapy (KST) for neonates has occurred. These efforts also include improving risk stratification (identifying high risk populations, including those with nephrotoxic medication exposure) and diagnostics (novel biomarkers and diagnostic tools). Recent work has also shown that the targeted use of methylxanthines may prevent AKI in a variety of high-risk populations. One of the most exciting developments in neonatal AKI is the advancement in technology to provide KST to neonates with severe AKI. In this comprehensive review we will provide an overview of recent work and advances in the field of neonatal AKI. This will include a detailed review of (1) the definition of neonatal AKI, (2) the epidemiology, risk factors, and outcomes associated with neonatal AKI, (3) improvements in risk stratification and diagnostics, (4) mitigation and treatment, (5) advancements in the provision of KST to neonates, and (6) the incidence and risk of subsequent CKD.