Renal outcome in children born preterm with neonatal acute renal failure: IRENEO-a prospective controlled study

A reappraisal of risk factors for hypertension after pediatric acute kidney injury

BACKGROUND

Acute kidney injury (AKI) is common in hospitalized children and increases the risk of chronic kidney disease (CKD) and hypertension, but little is known about the patient level risk factors for pediatric hypertension after AKI. The aims of this study are to evaluate the prevalence and risk factors for new onset hypertension in hospitalized children with AKI and to better understand the role of acute kidney disease (AKD) in the development of hypertension.

METHODS

This study was an observational cohort of all children ≤ 18 years old admitted to a single tertiary care children's hospital from 2015 to 2019 with a diagnosis of AKI. Hypertension was defined as blood pressure > 95th percentile for sex, age, height, diagnosis of hypertension on the problem list, or prescription of antihypertensive medication for > 90 days after AKI.

RESULTS

A total of 410 children were included in the cohort. Of these, 78 (19%) developed hypertension > 90 days after AKI. A multivariable logistic regression model identified AKD, need for kidney replacement therapy, congenital heart disease, and non-kidney solid organ transplantation as risk factors for hypertension after AKI.

CONCLUSIONS

Incident hypertension after 3 months is common among hospitalized children with AKI, and AKD, need for dialysis, congenital heart disease, and non-kidney solid organ transplant are significant risk factors for hypertension after AKI. Monitoring for hypertension development in these high-risk children is critical to mitigate long-term adverse kidney and cardiovascular outcomes.

Adolescent Kidney Outcomes after Extremely Preterm Birth and Neonatal Acute Kidney Injury: There May be More to the Story

OBJECTIVE

 Among children born extremely preterm (EP), the antecedents of chronic kidney disease (CKD), including neonatal acute kidney injury (nAKI), are not well characterized.

STUDY DESIGN

 This was a retrospective cohort pilot study. Participants (n = 36) were adolescents born before 28 weeks of gestation enrolled at birth into the extremely low gestational age newborn study, between 2002 and 2004, at the University of North Carolina. Participants were stratified by the primary exposure to nAKI, defined using the modified Kidney Disease Improving Global Outcomes nAKI criteria. Baseline serum creatinine (SCr) was defined as the lowest SCr after 48 to 72 postnatal hours. The primary outcome was an abnormal kidney profile during adolescence, defined as having one or more of these outcomes: elevated blood pressure (>120/80 mm Hg), microalbuminuria (urine microalbumin/creatinine >30 µg/g), or an abnormal kidney volume measured by ultrasound (total kidney volume corrected for body surface area <10th%ile for age).

RESULTS

 Half of the participants had a history of nAKI. Thirteen had stage 1 nAKI, four had stage 2, and one had stage 3 nAKI. At 15 years of age, 50% were overweight/obese, 31% had elevated blood pressure (BP), 11% had abnormal kidney volumes, and 17% had microalbuminuria. The relative risk for having an abnormal kidney profile during adolescence among participants with a history of nAKI was 0.63 (95% confidence interval: 0.3-1.3, p = 0.2).

CONCLUSION

 In this sample of adolescents born EP, a history of nAKI was not associated with elevated BP, microalbuminuria, or abnormal kidney volume. Future studies are needed in larger samples to better characterize the relationship between nAKI and CKD in EP-born children.

KEY POINTS

· Extremely preterm birth is associated with acute kidney injury.. · Extremely preterm birth is associated with chronic kidney disease.. · Neonatal acute kidney injury after extremely preterm birth was not associated with kidney outcomes..

When will the Glomerular Filtration Rate in Former Preterm Neonates Catch up with Their Term Peers?

AIMS

Whether and when glomerular filtration rate (GFR) in preterms catches up with term peers is unknown. This study aims to develop a GFR maturation model for (pre)term-born individuals from birth to 18 years of age. Secondarily, the function is applied to data of different renally excreted drugs.

METHODS

We combined published inulin clearance values and serum creatinine (Scr) concentrations in (pre)term born individuals throughout childhood. Inulin clearance was assumed to be equal to GFR, and Scr to reflect creatinine synthesis rate/GFR. We developed a GFR function consisting of GFRbirth (GFR at birth), and an Emax model dependent on PNA (with GFRmax, PNA50 (PNA at which half ofGFR max is reached) and Hill coefficient). The final GFR model was applied to predict gentamicin, tobramycin and vancomycin concentrations.

RESULT

In the GFR model, GFRbirth varied with birthweight linearly while in the PNA-based Emax equation, GA was the best covariate for PNA50, and current weight for GFRmax. The final model showed that for a child born at 26 weeks GA, absolute GFR is 18%, 63%, 80%, 92% and 96% of the GFR of a child born at 40 weeks GA at 1 month, 6 months, 1 year, 3 years and 12 years, respectively. PopPK models with the GFR maturation equations predicted concentrations of renally cleared antibiotics across (pre)term-born neonates until 18 years well.

CONCLUSIONS

GFR of preterm individuals catches up with term peers at around three years of age, implying reduced dosages of renally cleared drugs should be considered below this age.

Perinatal risk factors associated with acute kidney injury severity and duration among infants born extremely preterm

BACKGROUND

We evaluated time-varying perinatal risk factors associated with early (≤7 post-natal days) and late (>7 post-natal days) severe acute kidney injury (AKI) occurrence and duration.

METHODS

A secondary analysis of Preterm Erythropoietin Neuroprotection Trial data. We defined severe AKI (stage 2 or 3) per neonatal modified Kidney Disease: Improving Global Outcomes criteria. Adjusted Cox proportional hazards models were conducted with exposures occurring at least 72 h before severe AKI. Adjusted negative binomial regression models were completed to evaluate risk factors for severe AKI duration.

RESULTS

Of 923 participants, 2% had early severe AKI. In the adjusted model, gestational diabetes (adjusted HR (aHR) 5.4, 95% CI 1.1-25.8), non-steroidal anti-inflammatory drugs (NSAIDs) (aHR 3.2, 95% CI 1.0-9.8), and vancomycin (aHR 13.9, 95% CI 2.3-45.1) were associated with early severe AKI. Late severe AKI occurred in 22% of participants. Early severe AKI (aHR 2.5, 95% CI 1.1-5.4), sepsis (aHR 2.5, 95% CI 1.4-4.4), vasopressors (aHR 2.9, 95% CI 1.8-4.6), and diuretics (aHR 2.6, 95% CI 1.9-3.6) were associated with late severe AKI. Participants who had necrotizing enterocolitis or received NSAIDs had longer severe AKI duration.

CONCLUSION

We identified major risk factors for severe AKI that can be the focus of future research.

IMPACT STATEMENT

Time-dependent risk factors for severe acute kidney injury (AKI) and its duration are not well defined among infants born <28 weeks' gestation. Over 1 in 5 infants born <28 weeks' gestation experienced severe AKI, and this study identified several major time-dependent perinatal risk factors occurring within 72 h prior to severe AKI. This study can support efforts to develop risk stratification and clinical decision support to help mitigate modifiable risk factors to reduce severe AKI occurrence and duration.

Caffeine and kidney function at two years in former extremely low gestational age neonates

BACKGROUND

Extremely low gestational age neonates (ELGANs) are at risk for chronic kidney disease. The long-term kidney effects of neonatal caffeine are unknown. We hypothesize that prolonged caffeine exposure will improve kidney function at 22-26 months.

METHODS

Secondary analysis of the Preterm Erythropoietin Neuroprotection Trial of neonates <28 weeks' gestation. Participants included if any kidney outcomes were collected at 22-26 months corrected age. Exposure was post-menstrual age of caffeine discontinuation.

PRIMARY OUTCOMES

'reduced eGFR' <90 ml/min/1.73 m2, 'albuminuria' (>30 mg albumin/g creatinine), or 'elevated blood pressure' (BP) >95th %tile. A general estimating equation logistic regression model stratified by bronchopulmonary dysplasia (BPD) status was used.

RESULTS

598 participants had at least one kidney metric at follow up. Within the whole cohort, postmenstrual age of caffeine discontinuation was not associated with any abnormal measures of kidney function at 2 years. In the stratified analysis, for each additional week of caffeine, the no BPD group had a 21% decreased adjusted odds of eGFR <90 ml/min/1.73m2 (aOR 0.78; CI 0.62-0.99) and the BPD group had a 15% increased adjusted odds of elevated BP (aOR 1.15; CI: 1.05-1.25).

CONCLUSIONS

Longer caffeine exposure during the neonatal period is associated with differential kidney outcomes at 22-26 months dependent on BPD status.

IMPACT

In participants born <28 weeks' gestation, discontinuation of caffeine at a later post menstrual age was not associated with abnormal kidney outcomes at 22-26 months corrected age. When assessed at 2 years of age, later discontinuation of caffeine in children born <28 weeks' gestation was associated with a greater risk of reduced eGFR in those without a history of BPD and an increased odds of hypertension in those with a history of BPD. More work is necessary to understand the long-term impact of caffeine on the developing kidney.

Adults are just big kids: pediatric considerations for adult critical care nephrology

PURPOSE OF REVIEW

In recent years, there has been growing attention to pediatric kidney health, especially pediatric acute kidney injury (AKI). However, there has been limited focus on the role of pediatric AKI on adult kidney health, specifically considerations for the critical care physician.

RECENT FINDINGS

We summarize what is known in the field of pediatric AKI to inform adult medical care including factors throughout the early life course, including perinatal, neonatal, and pediatric exposures that impact survivor care later in adulthood.

SUMMARY

The number of pediatric AKI survivors continues to increase, leading to a higher burden of chronic kidney disease and other long-term co-morbidities later in life. Adult medical providers should consider pediatric history and illnesses to inform the care they provide. Such knowledge may help internists, nephrologists, and intensivists alike to improve risk stratification, including a lower threshold for monitoring for AKI and kidney dysfunction in their patients.

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.

Long-term outcomes of acute kidney injury in children

PURPOSE OF REVIEW

Acute kidney injury (AKI) affects up to 35% of all critically ill children and is associated with substantial short-term morbidity and mortality. However, the link between paediatric AKI and long-term adverse outcomes remains incompletely understood. This review highlights the most recent clinical data supporting the role of paediatric AKI as a risk factor for long-term kidney and cardiovascular consequences. In addition, it stresses the need for long-term surveillance of paediatric AKI survivors.

RECENT FINDINGS

Recent large-scale studies have led to an increasing understanding that paediatric AKI is a significant risk factor for adverse outcomes such as hypertension, cardiovascular disease and chronic kidney disease (CKD) over time. These long-term sequelae of paediatric AKI are most often observed in vulnerable populations, such as critically ill children, paediatric cardiac surgery patients, children who suffer from severe infections and paediatric cancer patients.

SUMMARY

A growing body of research has shown that paediatric AKI is associated with long-term adverse outcomes such as CKD, hypertension and cardiovascular disease. Although therapeutic pathways tailored to individual paediatric AKI patients are yet to be validated, we provide a framework to guide monitoring and prevention in children at the highest risk for developing long-term kidney dysfunction.

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.

Kidney outcomes in early adolescence following perinatal asphyxia and hypothermia-treated hypoxic-ischaemic encephalopathy

BACKGROUND

Acute kidney injury (AKI) remains common among infants with hypothermia-treated hypoxic-ischaemic encephalopathy (HIE). Little is known about long-term kidney outcomes following hypothermia treatment. We recently reported that 21% of survivors of hypothermia-treated HIE had decreased estimated glomerular filtration rate (eGFR) based on plasma creatinine in early adolescence. Here, we assessed kidney functions more comprehensively in our population-based cohort of children born in Stockholm 2007-2009 with a history of hypothermia-treated HIE.

METHODS

At 10-12 years of age, we measured cystatin C (cyst C) to estimate GFR. Children with decreased cyst C eGFR also underwent iohexol clearance examination. We measured urine-albumin/creatinine ratio, blood pressure (BP) and kidney volume on magnetic resonance imaging. Fibroblast growth factor 23 (FGF 23) levels in plasma were assessed by enzyme-linked immunosorbent assay (ELISA). Outcomes were compared between children with and without a history of neonatal AKI.

RESULTS

Forty-seven children participated in the assessment. Two children (2/42) had decreased cyst C eGFR, for one of whom iohexol clearance confirmed mildly decreased GFR. One child (1/43) had Kidney Disease Improving Global Outcomes (KDIGO) category A2 albuminuria, and three (3/45) had elevated office BP. Subsequent ambulatory 24-h BP measurement confirmed high normal BP in one case only. No child had hypertension. Kidney volume and FGF 23 levels were normal in all children. There was no difference in any of the parameters between children with and without a history of neonatal AKI.

CONCLUSION

Renal sequelae were rare in early adolescence following hypothermia-treated HIE regardless of presence or absence of neonatal AKI. A higher resolution version of the Graphical abstract is available as Supplementary information.

Prematurity and Congenital Heart Disease: A Contemporary Review

Congenital heart disease (CHD) is the most commonly reported birth defect in newborns. Neonates with CHD are more likely to be born prematurely, and a higher proportion of preterm neonates have CHD than their term counterparts. The implications of preterm birth on the cardiac and noncardiac organ systems are vast and require special management considerations. The feasibility of surgical interventions in preterm neonates is frequently limited by patient size and delicacy of immature cardiac tissues. Thus, special care must be taken when considering the appropriate timing and type of cardiac intervention. Despite improvements in neonatal cardiac surgical outcomes, preterm and early term gestational ages and low birthweight remain important risk factors for in-hospital mortality. Understanding the risks of early delivery of neonates with prenatally diagnosed CHD may help guide perioperative management in neonates who are born preterm. In this review, we will describe the risks and benefits of early delivery, postnatal cardiac and noncardiac evaluation and management, surgical considerations, overall outcomes, and future directions regarding optimization of perinatal evaluation and management of fetuses and preterm and early term neonates with CHD.

Incidence, Risk Factors, and Outcomes of Acute Kidney Injury in Necrotizing Enterocolitis: A Prospective Single-Center Study

Necrotizing enterocolitis (NEC) is a significant cause of morbidity and mortality in the neonatal intensive care unit (NICU). Acute kidney injury (AKI) is considered to be one of the most well-established risk factors for mortality in neonates. The aim of this work was to study the incidence of AKI in neonates with NEC and to determine the associated conditions, risk factors, and outcomes. We carried out this prospective cross-sectional study on 104 neonates treated for NEC from September 2015 to September 2019. Diagnoses of AKI were made using the neonatal modified Kidney Disease: Improved Global Outcome criteria. AKI occurred in 63 neonates (61%), with 32 at Stage 1 (31%), 20 at Stage 2 (19%), and 11 at Stage 3 (11%), including three requiring dialysis. Vancomycin use and positive blood culture were risk factors for developing AKI in our NEC neonates (odds ratio: 2.47 and 2.41; P = 0.03 and 0.04, respectively). Neonates with AKI had a higher mortality rate (47.6% vs. 26.8 %, P = 0.03) and an increased length of stay (LOS) (69.8 days vs. 53.9 days, P <0.01) than the non-AKI group. Surgical intervention was required in 11 (10.5%) of our neonates. We concluded that AKI occurs in about 60% of neonates with NEC and is associated with higher mortality and LOS in the NICU. Therefore, it is very important to identify and manage all neonates who are at a high risk of developing AKI as quickly as possible.

Long-term follow-up of patients after acute kidney injury in the neonatal period: abnormal ambulatory blood pressure findings

Background

Data on the long-term effects of neonatal acute kidney injury (AKI) are limited.

Methods

We invited 302 children who had neonatal AKI and survived to hospital discharge; out of 95 patients who agreed to participate in the study, 23 cases were excluded due to primary kidney, cardiac, or metabolic diseases. KDIGO definition was used to define AKI. When a newborn had no previous serum creatinine, AKI was defined as serum creatinine above the mean plus two standard deviations (SD) (or above 97.5^th percentile) according to gestational age, weight, and postnatal age. Clinical and laboratory features in the neonatal AKI period were recorded for 72 cases; at long-term evaluation (2–12 years), kidney function tests with glomerular filtration rate (eGFR) by the Schwartz formula, microalbuminuria, office and 24-h ambulatory blood pressure monitoring (ABPM), and kidney ultrasonography were performed.

Results

Forty-two patients (58%) had stage I AKI during the neonatal period. Mean age at long-term evaluation was 6.8 ± 2.9 years (range: 2.3–12.0); mean eGFR was 152.3 ± 26.5 ml/min/1.73 m². Office hypertension (systolic and/or diastolic BP ≥ 95^th percentile), microalbuminuria (> 30 mg/g creatinine), and hyperfiltration (> 187 ml/min/1.73 m²) were present in 13.0%, 12.7%, and 9.7% of patients, respectively. ABPM was performed on 27 patients, 18.5% had hypertension, and 40.7% were non-dippers; 48.1% had abnormal findings. Female sex was associated with microalbuminuria; low birth weight (< 1,500 g) and low gestational age (< 32 weeks) were associated with hypertension by ABPM. Twenty-three patients (33.8%) had at least one sign of microalbuminuria, office hypertension, or hyperfiltration. Among 27 patients who had ABPM, 16 (59.3%) had at least one sign of microalbuminuria, abnormal ABPM (hypertension and/or non-dipping), or hyperfiltration.

Conclusion

Even children who experienced stage 1 and 2 neonatal AKI are at risk for subclinical kidney dysfunction. Non-dipping is seen in four out of 10 children. Long-term follow-up of these patients is necessary.

Clinical course of neonatal acute kidney injury: multi-center prospective cohort study

Background

Neonatal acute kidney injury (AKI) has been associated with unfavorable outcomes, including increased mortality. We aimed to describe the clinical course and outcomes during the first 7 days after diagnosis in newborns with AKI in three neonatal intensive care units in Popayán-Colombia.

Methods

Multi-center prospective cohort study conducted between June 2019 and December 2020 in three NICUs after ethical approval. We included newborns between 2 and 28 days of life, first diagnosed with AKI using the KDIGO classification modified for newborns which consider increased serum creatinine values over baseline values as well as urine output over time in hours or both. Patients with chromosomal abnormalities, major kidney malformations, and complex congenital heart disease were excluded. Patients were followed for up to 7 days after diagnosis and the maximum KDIGO stage, recovery of kidney function, need for renal replacement therapy and cumulative incidence of death were evaluated.

Results

Over the 18 months of the study, 4132 newborns were admitted to the NICUs, and 93 patients (2.25, 95% CI 1.82–2.75%) developed neonatal AKI. 59.1% of the newborns were premature and there were no differences in severity according to gestational age. During follow-up, the maximum KDIGO was 64.5% for AKI-stage 1, 11.8% for AKI-stage 2, and 23.7% for AKI-stage 3. Kidney function recovery was higher in AKI-stage 1 patients vs. AKI-severe (AKI-stage 2 and 3) (95% vs. 48.5%). Five patients (5.4%) received renal replacement therapy and 15 died (16.1%), four in AKI-stage 1 vs. 11 in AKI-severe (6.7% vs 33.3%).

Conclusions

Newborns admitted to the NICUs can develop AKI regardless of gestational age, and it is more frequent between the second and ninth days of life. More patients whit AKI-stage 1 recover and die less than those in a severe stage.

The developmental origins of health and chronic kidney disease: Current status and practices in Japan

The concept of the developmental origins of health and disease (DOHaD) views unfavorable perinatal circumstances as contributing to the development of diseases in later life. It is well known that such unfavorable circumstances play an important role as a risk factor for chronic kidney disease (CKD) in infants born with prematurity. Low birthweight (LBW) is believed to be a potential contributor to CKD in adulthood. Preterm and/or LBW infants are born with incomplete nephrogenesis. As a result, the number of nephrons is low. The poor intrauterine environment also causes epigenetic changes that adversely affect postnatal renal function. After birth, hyperfiltration of individual nephrons due to low nephron numbers causes proteinuria and secondary glomerulosclerosis. Furthermore, the risk of CKD increases as renal damage takes a second hit from exposure to nephrotoxic substances and acquired insults such as acute kidney injury after birth among infants in neonatal intensive care. Meanwhile, unfortunately, recent studies have shown that the number of nephrons in healthy Japanese individuals is approximately two-thirds lower than that in previous reports. This means that Japanese premature infants are clearly at a high risk of developing CKD in later life. Recently, several DOHaD-related CKD studies from Japanese researchers have been reported. Here, we summarize the relevance of CKD in conjunction with DOHaD and review recent studies that have examined the impact of the upward LBW trend in Japan on renal health.

Advances in Neonatal Acute Kidney Injury

In this state-of-the-art review, we highlight the major advances over the last 5 years in neonatal acute kidney injury (AKI). Large multicenter studies reveal that neonatal AKI is common and independently associated with increased morbidity and mortality. The natural course of neonatal AKI, along with the risk factors, mitigation strategies, and the role of AKI on short- and long-term outcomes, is becoming clearer. Specific progress has been made in identifying potential preventive strategies for AKI, such as the use of caffeine in premature neonates, theophylline in neonates with hypoxic-ischemic encephalopathy, and nephrotoxic medication monitoring programs. New evidence highlights the importance of the kidney in "crosstalk" between other organs and how AKI likely plays a critical role in other organ development and injury, such as intraventricular hemorrhage and lung disease. New technology has resulted in advancement in prevention and improvements in the current management in neonates with severe AKI. With specific continuous renal replacement therapy machines designed for neonates, this therapy is now available and is being used with increasing frequency in NICUs. Moving forward, biomarkers, such as urinary neutrophil gelatinase-associated lipocalin, and other new technologies, such as monitoring of renal tissue oxygenation and nephron counting, will likely play an increased role in identification of AKI and those most vulnerable for chronic kidney disease. Future research needs to be focused on determining the optimal follow-up strategy for neonates with a history of AKI to detect chronic kidney disease.

Neonatal acute kidney injury: a case-based approach

Neonatal acute kidney injury (AKI) is increasingly recognized as a common complication in critically ill neonates. Over the last 5-10 years, there have been significant advancements which have improved our understanding and ability to care for neonates with kidney disease. A variety of factors contribute to an increased risk of AKI in neonates, including decreased nephron mass and immature tubular function. Multiple factors complicate the diagnosis of AKI including low glomerular filtration rate at birth and challenges with serum creatinine as a marker of kidney function in newborns. AKI in neonates is often multifactorial, but the cause can be identified with careful diagnostic evaluation. The best approach to treatment in such patients may include diuretic therapies or kidney support therapy. Data for long-term outcomes are limited but suggest an increased risk of chronic kidney disease (CKD) and hypertension in these infants. We use a case-based approach throughout this review to illustrate these concepts and highlight important evidence gaps in the diagnosis and management of neonatal AKI.

Effects of prematurity on long-term renal health: a systematic review

OBJECTIVE

To investigate the literature and determine if prematurity has an impact on long-term adverse kidney outcomes.

DESIGN

Systematic review.

DATA SOURCES

OVID Medline, PubMed, SCOPUS, CINAHL and EMBASE databases were searched for studies relating to the adverse outcomes of prematurity from 1990 to April 2021.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

All articles published between January 1990 and April 2021 that investigated whether premature infants developed long-term adverse renal outcomes were included in this review. Articles must have been human studies and written in English. Case series with less than 20 participants and case studies were excluded.

DATA EXTRACTION AND SYNTHESIS

One reviewer completed the database searches. Article selection was performed independently and in a non-blinded manner by both reviewers. Initial screening was by title and abstract. Full texts of remaining articles were reviewed. Articles for which inclusion was unclear were re-reviewed by both reviewers, and a unanimous decision was taken as to whether they should be included. The Newcastle-Ottawa Scale was used for quality assessment of the included articles.

RESULTS

The literature search yielded 31 human studies, which investigated the short-term and long-term kidney outcomes of prematurity. These studies were conducted in 17 different countries. The most common outcomes measured were blood pressure (BP) and glomerular filtration rate. Other common outcomes measured included kidney size and mass, proteinuria, albuminuria, chronic kidney disease (CKD) and physical parameters such as height, weight and body mass index.

CONCLUSION

Prematurity is likely linked to increased risk of kidney dysfunction and high BP in childhood and into early adulthood. Premature birth conferred a twofold increased risk of CKD and extremely premature birth conferred a threefold increased risk of CKD. However, further larger multicentre studies are needed to draw definitive conclusions on the long-term kidney outcomes of prematurity.

Renal insufficiency in children born preterm: examining the role of neonatal acute kidney injury

OBJECTIVE

To identify the prevalence of renal insufficiency (RI) in children with a history of prematurity and acute kidney injury (AKI).

STUDY DESIGN

This prospective cohort study evaluated renal function in children born preterm at 5-9 years of age. Univariable analyses compared perinatal and follow-up data from subjects with and without AKI history, and with and without current RI. Regression analyses were attempted to model RI as a function of AKI and other clinical risk factors.

RESULTS

Fifteen of 43 (35%) participants had previously undiagnosed RI. Only children with no AKI history or neonatal stage 1 AKI presented for follow-up. Children born preterm with a history of stage 1 AKI had higher serum creatinine (sCr) at follow-up, but were not more likely to have RI compared to children without stage 1 AKI history (RI prevalence 30% and 36% in AKI and non-AKI group, respectively).

CONCLUSION

The high prevalence of RI in this preterm cohort at middle childhood follow-up highlights the need for routine kidney health assessments in this population. Large multicenter studies are needed to further characterize the impact of premature birth and mild AKI on renal function throughout childhood.

Nephron number and its determinants: a 2020 update

Studies of human nephron number have been conducted for well over a century and have uncovered a large variability in nephron number. However, the mechanisms influencing nephron endowment and loss, along with the etiology for the wide range among individuals are largely unknown. Advances in imaging technology have allowed investigators to revisit the principles of renal structure and physiology and their roles in the progression of kidney disease. Here, we will review the latest data on the influences impacting nephron number, innovations made over the last 6 years to understand and integrate renal structure and function, and new developments in the tools used to count nephrons in vivo.

Preterm birth and neonatal acute kidney injury: implications on adolescent and adult outcomes

As a result of preterm birth, immature kidneys are exposed to interventions in the NICU that promote survival, but are nephrotoxic. Furthermore, the duration of renal development may be truncated in these vulnerable neonates. Immaturity and nephrotoxic exposures predispose preterm newborns to acute kidney injury (AKI), particularly in the low birth weight and extremely preterm gestational age groups. Several studies have associated preterm birth as a risk factor for future chronic kidney disease (CKD). However, only a few publications have investigated the impact of neonatal AKI on CKD development. Here, we will review the evidence linking preterm birth and AKI in the NICU to CKD and highlight the knowledge gaps and opportunities for future research. For neonatal intensive care studies, we propose the inclusion of AKI as an important short-term morbidity outcome and CKD findings such as a reduced glomerular filtration rate in the assessment of long-term outcomes.

Long-term complications of acute kidney injury in children

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

Acute kidney injury in sick neonates: a comparative study of diagnostic criteria, assessment of risk factors and outcomes

Introduction: Neonatal acute kidney injury (nAKI) poses unique challenges with diagnostic criteria specific to neonates evolving over time. Urine output (UOP) criterion has a special place in the diagnosis of nAKI although significant clarity on the ideal diagnostic threshold for UOP is not established. Risk factors peculiar to the tropical region for acute kidney injury (AKI) in neonates needs attention. It would be interesting to assess for kidney function in neonates who survived AKI during the dynamic phase of infancy.Objectives: To compare criteria of modified kidney disease improving global outcome (mKDIGO) and neonatal risk, injury, failure, loss, and end-stage criteria (nRIFLE) in diagnosing AKI in sick neonates; to study the risk factors for AKI and clinical outcomes at the end of neonatal ICU stay and during infancy.Methods: This prospective study was conducted at a tertiary neonatal ICU that screened and staged sick neonates by applying mKDIGO and nRIFLE criteria. Risk factors were assessed and glomerular filtration rate was calculated by cystatin C in survivors of nAKI for 12 months post conception age.Results: nAKI was observed in 30% (49/163) of sick neonates. The mKDIGO (94%) detected a higher number of neonates with AKI compared to nRIFLE (49%). Based on only UOP, nRIFLE diagnosed a higher proportion of neonates with mild AKI compared to mKDIGO (29% versus 16%), respectively. Besides known risk factors, hypernatremic dehydration (18%) was an important risk factor for AKI. With 20% mortality, the risk of developing AKI was comparable using either mKDIGO or nRIFLE diagnostic criteria. At the end of infancy, mean cystatin C eGFR of neonates was 101.3 ± 29.2 ml/1.73 m²/min.Conclusion: In sick neonates, mKDIGO criteria performed better than nRIFLE in detecting AKI. However, the risk of mortality was comparable using either diagnostic criterion. Hypernatremic dehydration was an important risk factor for AKI and renal function of neonates following complete recovery of AKI was normal at the end of infancy.

The Effect of Preterm Birth on Renal Development and Renal Health Outcome

Preterm birth is associated with adverse renal health outcomes including hypertension, chronic kidney disease, and an increased rate of progression to end-stage renal failure. This review explores the antenatal, perinatal, and postnatal factors that affect the functional nephron mass of an individual and contribute to long-term kidney outcome. Health-care professionals have opportunities to increase their awareness of the risks to kidney health in this population. Optimizing maternal health around the time of conception and during pregnancy, providing kidney-focused supportive care in the NICU during postnatal nephrogenesis, and avoiding accelerating nephron loss throughout life may all contribute to improved long-term outcomes. There is a need for ongoing research into the long-term kidney outcomes of preterm survivors in mid-to-late adulthood as well as a need for further research into interventions that may improve ex utero nephrogenesis.

Clinical consequences of developmental programming of low nephron number

Nephron number in humans varies up to 13-fold, likely reflecting the impact of multiple factors on kidney development, including inherited body size and ethnicity, as well as maternal health and nutrition, fetal exposure to gestational diabetes or preeclampsia and other environmental factors, which may potentially be modifiable. Such conditions predispose to low or high offspring birth weight, growth restriction or preterm birth, which have all been associated with increased risks of higher blood pressures and/or kidney dysfunction in later life. Low birth weight, preterm birth, and intrauterine growth restriction are associated with reduced nephron numbers. Humans with hypertension and chronic kidney disease tend to have fewer nephrons than their counterparts with normal blood pressures or kidney function. A developmentally programmed reduction in nephron number therefore enhances an individual's susceptibility to hypertension and kidney disease in later life. A low nephron number at birth may not lead to kidney dysfunction alone except when severe, but in the face of superimposed acute or chronic kidney injury, a kidney endowed with fewer nephrons may be less able to adapt, and overt kidney disease may develop. Given that millions of babies are born either too small, too big or too soon each year, the population impact of altered renal programming is likely to be significant. Many gestational exposures are modifiable, therefore urgent attention is required to implement public health measures to optimize maternal, fetal, and child health, to prevent or mitigate the consequences of developmental programming, to improve the health future generations.

Maternal and environmental risk factors for neonatal AKI and its long-term consequences

Acute kidney injury (AKI) is a common and life-threatening complication in critically ill neonates. Gestational risk factors for AKI include premature birth, intrauterine growth restriction and low birthweight, which are associated with poor nephron development and are often the consequence of pre-gestational and gestational factors, such as poor nutritional status. Our understanding of how to best optimize renal development and prevent AKI is in its infancy; however, the identification of pre-gestational and gestational factors that increase the risk of adverse neonatal outcomes and the implementation of interventions, such as improving nutritional status early in pregnancy, have the potential to optimize fetal growth and reduce the risk of preterm birth, thereby improving kidney health. The overall risk of AKI among critically ill and premature neonates is exacerbated postnatally as these infants are often exposed to dehydration, septic shock and potentially nephrotoxic medications. Strategies to improve outcomes - for example, through careful evaluation of nephrotoxic drugs - may reduce the incidence of AKI and its consequences among this population. Management strategies and updated technology that will support neonates with AKI are greatly needed. Extremely premature infants and those who survive an episode of AKI should be screened for chronic kidney disease until early adulthood. Here, we provide an overview of our current understanding of neonatal AKI, focusing on its relationship to preterm birth and growth restriction. We describe factors that prevent optimal nephrogenesis during pregnancy and provide a framework for future explorations designed to maximize outcomes in this vulnerable population.

Preterm birth and risk of chronic kidney disease from childhood into mid-adulthood: national cohort study

OBJECTIVE

To investigate the relation between preterm birth (gestational age <37 weeks) and risk of CKD from childhood into mid-adulthood.

DESIGN

National cohort study.

SETTING

Sweden.

PARTICIPANTS

4 186 615 singleton live births in Sweden during 1973-2014.

EXPOSURES

Gestational age at birth, identified from nationwide birth records in the Swedish birth registry.

MAIN OUTCOME MEASURES

CKD, identified from nationwide inpatient and outpatient diagnoses through 2015 (maximum age 43 years). Cox regression was used to examine gestational age at birth and risk of CKD while adjusting for potential confounders, and co-sibling analyses assessed the influence of unmeasured shared familial (genetic or environmental) factors.

RESULTS

4305 (0.1%) participants had a diagnosis of CKD during 87.0 million person years of follow-up. Preterm birth and extremely preterm birth (<28 weeks) were associated with nearly twofold and threefold risks of CKD, respectively, from birth into mid-adulthood (adjusted hazard ratio 1.94, 95% confidence interval 1.74 to 2.16; P<0.001; 3.01, 1.67 to 5.45; P<0.001). An increased risk was observed even among those born at early term (37-38 weeks) (1.30, 1.20 to 1.40; P<0.001). The association between preterm birth and CKD was strongest at ages 0-9 years (5.09, 4.11 to 6.31; P<0.001), then weakened but remained increased at ages 10-19 years (1.97, 1.57 to 2.49; P<0.001) and 20-43 years (1.34, 1.15 to 1.57; P<0.001). These associations affected both males and females and did not seem to be related to shared genetic or environmental factors in families.

CONCLUSIONS

Preterm and early term birth are strong risk factors for the development of CKD from childhood into mid-adulthood. People born prematurely need long term follow-up for monitoring and preventive actions to preserve renal function across the life course.

Neonatal Acute Kidney Injury: A Survey of Perceptions and Management Strategies Amongst Pediatricians and Neonatologists

Background: Neonatal Acute Kidney Injury (AKI) occurs in 40-70% of critically ill newborn infants and is independently associated with increased morbidity and mortality. Understanding the practice patterns of physicians (neonatologists and pediatricians), caring for neonates in India is important to optimize care and outcomes in neonatal AKI. Aim: The aim of this study was to identify differences in physician's perception and practice variations of diagnosis, management, and follow-up of newborn infants with AKI in India. Methods: An online survey of neonatologists and pediatricians in India caring for newborn infants with AKI. Results: Out of 800 correspondents, 257 (135 neonatologists and 122 pediatricians) completed the survey, response rate being 32.1%. Resources available to the respondents included level III NICU (59%), neonatal surgery (60%), dialysis (11%), and extracorporeal membrane oxygenation (ECMO, 3%). Most respondents underestimated the risk of AKI due to various risk factors such as prematurity, asphyxia, sepsis, cardiac surgery, and medications. Less than half the respondents were aware of the AKIN or KDIGO criteria, which are the current standard criteria for defining neonatal AKI. Only half of the respondents were aware of the risk of CKD in preterm neonates and nearly half were unaware of the need to follow up with a pediatric nephrologist. Conclusions: Similar to other regions worldwide, there exists a knowledge gap in early recognition, optimal management and follow up of newborn infants with AKI amongst Indian physicians.

Is acute kidney injury a harbinger for chronic kidney disease?

PURPOSE OF REVIEW

Despite abundant evidence in adults, the relationship between acute kidney injury (AKI) and chronic kidney disease (CKD) remains unanswered in pediatrics. Obstacles to overcome include the challenges defining these entities and the lack of long-term follow-up studies. This review focuses on pediatric populations at high-risk for AKI, the evidence of the long-term effect of AKI on renal health, and biomarkers to detect renal disease.

RECENT FINDINGS

AKI in critically ill children and neonates is common and independently associated with adverse outcomes. Patients with diabetes and sickle cell disease along with neonates with necrotizing enterocolitis have been identified as high-risk for AKI. Preterm birth and neonates with AKI have signs of renal dysfunction early in childhood. Urinary biomarkers may identify AKI and CKD earlier than traditional biomarkers, but more work is necessary to determine their clinical utility. Promising technological advances including the ability to determine nephron number noninvasively will expand our ability to characterize the AKI to CKD transition.

SUMMARY

AKI is common and associated with poor outcomes. It is probable that AKI is a harbinger to CKD in pediatric populations. However, we currently lack the tools to definitely answer this question and more research is needed.

Ibuprofen exposure in early neonatal life does not affect renal function in young adolescence

INTRODUCTION

Ibuprofen exposure results in acute transient renal dysfunction in preterm neonates, but we are unaware of data on long-term renal safety.

METHODS

In a previously studied cohort of extreme low birth weight (ELBW, <1000 g) cases, the PREMATurity as predictor of children's Cardiovascular-renal Health study generated data on renal function (renal length, estimated glomerular filtration rate based on cystatin C (eGFR_cysC) at the age of 11 years. This data set in 93 ELBW cases may also generate data on long-term drug safety on ibuprofen. In this post hoc analysis, we linked markers of renal function in young adolescence in ELBW cases with their perinatal (prenatal maternal, setting at birth, treatment modalities including drug prescription during neonatal stay, neonatal creatinine values, postdischarge growth) characteristics, including but not limited to ibuprofen exposure during neonatal stay.

RESULTS

Ibuprofen exposure was not associated with significant differences in renal length or eGFR_cysC. Moreover, we were unable to identify any other risk factor (perinatal characteristics, postnatal creatinine trends, postdischarge growth) on renal outcome in this cohort.

CONCLUSIONS

Neonatal exposure to ibuprofen did not affect renal function. Larger studies are needed to explore the confounders of variability in renal function in former ELBW cases. This matters since ELBW relates to risk for hypertension, cardiovascular events and renal disease in later life and identification of risk factors holds the promise of secondary prevention.

TRIAL REGISTRATION NUMBER

NCT02147457.

Acute kidney injury in necrotizing enterocolitis predicts mortality

BACKGROUND

Morbidity and mortality with necrotizing enterocolitis (NEC) remains a significant challenge. Acute kidney injury (AKI) has been shown to worsen survival in critically ill neonates. To our knowledge, this study is the first to evaluate the prevalence of AKI and its impact on outcomes in neonatal NEC.

METHODS

We carried out a single-center retrospective chart review of all neonates treated for NEC between 2003 and 2015 (N = 181). AKI is defined as a rise in serum creatinine (SCr) from a previous trough according to neonatal modified KDIGO criteria (stage 1 = SCr rise 0.3 mg/dL or SCr 150 < 200%, stage 2 = SCr rise 200 < 300%, stage 3 = SCr rise ≥300%, SCr 2.5 mg/dL or dialysis). Primary outcome was in-hospital mortality and secondary outcomes were hospital length of stay (LOS) and need for and type of surgery.

RESULTS

Acute kidney injury occurred in 98 neonates (54%), with 39 stage 1 (22%), 31 stage 2 (18%), and 28 stage 3 (16%), including 5 requiring dialysis. Non-AKI and AKI groups were not statistically different in age, weight, Bell's NEC criteria, and medication exposure (vasopressors, vancomycin, gentamicin, or diuretic). Neonates with AKI had higher mortality (44% vs 25.6%, p = 0.008) and a higher chance of death (HR 2.4, CI 1.2-4.8, p = 0.009), but the effect on LOS on survivors did not reach statistical significance (79 days, interquartile range [IQR] 30-104 vs 54 days, IQR 30-92, p = 0.09). Overall, 48 (27.9%) patients required surgical intervention.

CONCLUSIONS

This study shows that AKI not only occurs in over half of patients with NEC, but that it is also associated with more than a two-fold higher mortality, highlighting the importance of early recognition and potentially early intervention for AKI.

Preterm Birth: Long Term Cardiovascular and Renal Consequences

BACKGROUND

Cardiovascular and chronic kidney diseases are a part of noncommunicable chronic diseases, the leading causes of premature death worldwide. They are recognized as having early origins through altered developmental programming, due to adverse environmental conditions during development. Preterm birth is such an adverse factor. Rates of preterm birth increased in the last decades, however, with the improvement in perinatal and neonatal care, a growing number of preterm born subjects has now entered adulthood. Clinical and experimental evidence suggests that preterm birth is associated with impaired or arrested structural or functional development of key organs/systems making preterm infants vulnerable to cardiovascular and chronic renal diseases at adulthood. This review analyzes the evidence of such cardiovascular and renal changes, the role of perinatal and neonatal factors such as antenatal steroids and potential pathogenic mechanisms, including developmental programming and epigenetic alterations.

CONCLUSION

Preterm born subjects are exposed to a significantly increased risk for altered cardiovascular and renal functions at young adulthood. Adequate, specific follow-up measures remain to be determined. While antenatal steroids have considerably improved preterm birth outcomes, repeated therapy should be considered with caution, as antenatal steroids induce long-term cardiovascular and metabolic alterations in animals' models and their involvement in the accelerated cellular senescence observed in human studies cannot be excluded.

Acute kidney injury in premature newborns-definition, etiology, and outcome

BACKGROUND

Neonatal acute kidney injury (AKI) is common and is associated with poor outcomes. New criteria for the diagnosis of AKI were introduced based on the increase in serum creatinine (SCr) levels and/or reduction of urine output (UOP). Yet, there is no generally accepted opinion so far, which criteria (whether SCr, UOP, or their combination) are the most appropriate to diagnose neonatal AKI.

METHODS

The retrospective study included 195 prematurely born neonates who fulfilled all inclusion criteria (with at least two SCr measurements). In all the neonates included in the study, AKI was diagnosed using three different definitions: (1) SCr criteria (an increase in SCr values of ≥0.3 mg/dl), (2) UOP criteria (UOP < 1.5 ml/kg/h), and (3) SCr + UOP criteria.

RESULTS

Out of all of the patients the study included, 85 (44%) were diagnosed with AKI. The neonates who had AKI had a significantly lower gestational age, birth weight, and Apgar score, longer duration of mechanical ventilation, and a higher mortality rate. SCr + UOP criteria showed higher sensitivity for prediction of death compared to SCr or UOP alone (p = 0.0008, 95% CI 0.040-0.154, and p = 0.0038, 95% CI 0.024-0.125, respectively). If only SCr or only UOP criterion are used, they fail to identify AKI in 61 and 67%, respectively. AKI was an independent risk factor for death (OR 7.4875; CI 3.1887-17.5816).

CONCLUSIONS

Similar to other studies, our data showed that neonates with AKI have worse outcome. Neonatal AKI defined based on SCr + UOP criteria is a better predictor of death than neonatal AKI defined based only on the SCr or UOP criteria. Also, by using SCr + UOP criteria for diagnosing neonatal AKI, more patients with AKI are recruited than when only one of those criteria is used.

Long-Term Impact of Preterm Birth: Neurodevelopmental and Physical Health Outcomes

Preterm birth severely disrupts the normal developmental maturation of organ systems, resulting in lasting adverse effects. High blood pressure, cardiac dysfunction, obstructive lung disease, elevated blood glucose, and mental health problems occur earlier and at higher rates in the preterm-born than in the term populations. Disadvantageous health conditions may have a significant impact on the well-being of preterm-born individuals from childhood through adulthood. This review summarizes the impact of preterm birth on neurodevelopment and on cardiovascular, renal, metabolic, and pulmonary health.

Follow-up of Acute kidney injury in Neonates during Childhood Years (FANCY): a prospective cohort study

BACKGROUND

Very low birth weight (VLBW) neonates commonly experience acute kidney injury (AKI) in the neonatal intensive care unit (NICU). We hypothesize that VLBW neonates exposed to AKI in the NICU might be at a higher risk of renal dysfunction during childhood.

METHODS

In this cohort study, VLBW children (aged 3-7 years) completed a kidney health evaluation and were stratified according to AKI status in the NICU. The primary outcome was renal dysfunction defined as any of the following: estimated glomerular filtration rate (eGFR) <90 mL/min/1.73 m², urine protein/creatinine >0.2 or blood pressure ≥95th percentile.

RESULTS

Thirty-four subjects completed the study. Twenty subjects had a history of neonatal AKI (stage 1, n = 8; stage 2, n = 9; and stage 3, n = 3). At a median age of 5 years, the AKI group had a higher risk of renal dysfunction compared with the group without AKI (65% vs 14%, relative risk 4.5 (1.2-17.1), p = 0.01). Overall, 26% of the total cohort had an eGFR <90 mL/min/1.73 m² using serum cystatin C (35% of AKI subjects, 14% of no AKI subjects, p = 0.25).

CONCLUSIONS

Evidence of renal dysfunction in neonates born VLBW can be found early in childhood. Further work is necessary to determine how to reduce renal disease in this vulnerable population.

The Impact of Kidney Development on the Life Course: A Consensus Document for Action

Hypertension and chronic kidney disease (CKD) have a significant impact on global morbidity and mortality. The Low Birth Weight and Nephron Number Working Group has prepared a consensus document aimed to address the relatively neglected issue for the developmental programming of hypertension and CKD. It emerged from a workshop held on April 2, 2016, including eminent internationally recognized experts in the field of obstetrics, neonatology, and nephrology. Through multidisciplinary engagement, the goal of the workshop was to highlight the association between fetal and childhood development and an increased risk of adult diseases, focusing on hypertension and CKD, and to suggest possible practical solutions for the future. The recommendations for action of the consensus workshop are the results of combined clinical experience, shared research expertise, and a review of the literature. They highlight the need to act early to prevent CKD and other related noncommunicable diseases later in life by reducing low birth weight, small for gestational age, prematurity, and low nephron numbers at birth through coordinated interventions. Meeting the current unmet needs would help to define the most cost-effective strategies and to optimize interventions to limit or interrupt the developmental programming cycle of CKD later in life, especially in the poorest part of the world.

Renal consequences of preterm birth

Background

The developmental origin of health and disease concept identifies the brain, cardiovascular, liver, and kidney systems as targets of fetal adverse programming with adult consequences. As the limits of viability in premature infants have been pushed to lower gestational ages, the long-term impact of prematurity on kidneys still remains a significant burden during hospital stay and beyond.

Objectives

The purpose of this study is to summarize available evidence, mechanisms, and short- and long-term renal consequences of prematurity and identify nephroprotective strategies and areas of uncertainty.

Results

Kidney size and nephron number are known to be reduced in surviving premature infants due to disruption of organogenesis at a crucial developmental time point. Inflammation, hyperoxia, and antiangiogenic factors play a role in epigenetic conditioning with potential life-long consequences. Additional kidney injury from hypoperfusion and nephrotoxicity results in structural and functional changes over time which are often unnoticed. Nephropathy of prematurity and acute kidney injury confound glomerular and tubular maturation of preterm kidneys. Kidney protective strategies may ameliorate growth failure and suboptimal neurodevelopmental outcomes in the short term. In later life, subclinical chronic renal disease may progress, even in asymptomatic survivors.

Conclusion

Awareness of renal implications of therapeutic interventions and renal conservation efforts may lead to a variety of short and long-term benefits. Adequate monitoring and supplementation of microelement losses, gathering improved data on renal handling, and exploration of new avenues such as reliable markers of injury and new therapeutic strategies in contemporary populations, as well as long-term follow-up of renal function, is warranted.