Albuminuria in children

Reference ranges for 24-h urinary protein/creatinine ratio and urinary microalbumin/creatinine ratio in Chinese children

BACKGROUND

The purpose of this study was to investigate the age and gender characteristics of 24-h urinary protein/creatinine ratio (24hUPCR) and urinary microalbumin/creatinine ratio (UMACR) among Chinese children and other related factors, and to establish preliminary reference ranges.

METHODS

A total of 200 healthy children aged 2-15 years were enrolled. We divided the subjects into twelve groups according to age. Kruskal-Wallis one-way ANOVA test and Spearman correlation analysis were used to compare 24hUPCR and UMACR with other variables and 95% reference range was used to establish the reference range.

RESULTS

24hUPCR and UMACR showed correlation with age, height, weight, and body mass index (BMI) (p < 0.001), and females had higher levels than males among all healthy children (p < 0.01). 6 and 8 years of age were the critical nodes in the change of 24hUPCR and UMACR levels, respectively. The reference ranges established based on the 200 Chinese children in this study are as follows: 24hUPCR: < 24.34 mg/mmol (male) and < 43.04 mg/mmol (female) for ≥ 2-6 years; < 17.60 mg/mmol (male) and < 22.80 mg/mmol (female) for ≥ 6-15 years.

UMACR

 < 1.53 mg/mmol (male) and < 1.74 mg/mmol (female) for ≥ 2-8 years, < 1.13 mg/mmol (male) and < 3.48 mg/mmol (female) for ≥ 8-15 years.

CONCLUSIONS

24hUPCR and UMACR in children were correlated with age, gender, height, weight, BMI, and ethnicity. Establishing the right pediatric cutoff values that account for age, gender, and ethnicity can guarantee the sensitivity and specificity needed for clinical applications.

Non-linear relationship between body roundness index and albuminuria among children and adolescents aged 8-19 years: A cross-sectional study

INTRODUCTION

Obesity has been found to be correlated with numerous health issues, including an elevated risk of albuminuria in adults. However, this correlation is still controversial among children and adolescents, as several recent large-scale cross-sectional studies have observed a negative correlation between obesity and albuminuria. Our study aimed to investigate the link between the body roundness index (BRI) and albuminuria among children and adolescents, in order to further understand the correlation between obesity and albuminuria in this demographic.

METHODS

We employed information from the National Health and Nutrition Examination Survey (NHANES) 1999-2010 for cross-sectional analysis. Weighted logistic regression was employed to explore the linear relationship between BRI and albuminuria, with subgroup analyses performed for more detailed insights. Weighted linear regression analysis was employed to explore the relationship between BRI and the urine albumin-creatinine ratio (UACR). Additionally, we applied smooth curve fitting to investigate their non-linear relationship and conducted threshold effect analysis to identify any turning point.

RESULTS

In this study of 15,487 participants aged 8-19 years, multivariate logistic regression analysis revealed a significant negative correlation between BRI and albuminuria (OR = 0.616, 95%CI: 0.526-0.722). The relationship between BRI and UACR, as shown by multivariate linear regression analysis, was significantly inversely correlated (β: -5.424, 95%CI: -7.416 to -3.433). Furthermore, smooth curve fitting and threshold effect analysis showed a non-linear relationship between BRI and albuminuria, with a BRI inflection point identified at 2.906.

CONCLUSIONS

These findings of our study suggest a significant nonlinear negative association between BRI and the presence of albuminuria among children and teenagers, and maintaining an appropriate BRI may decrease the occurrence of albuminuria in this population.

Long-term kidney outcomes in children after allogeneic hematopoietic stem cell transplantation assessed with estimated glomerular filtration rate equations, creatinine levels, and cystatin C levels

BACKGROUND AND OBJECTIVE

With the widespread use of allogeneic hematopoietic stem cell transplantation (allo-HSCT), long-term complications have come to the fore. The aim of this study was to determine the prevalence and risk factors of chronic kidney disease (CKD) developing in the long term in patients who underwent allo-HSCT in childhood and also to investigate the superiority of eGFR formulas.

METHODS

The present study evaluated CKD in patients who underwent allo-HSCT. We analyzed the 94 children who received allo-HSCT at the Ege University in İzmir between August and November, 2019. The patients were evaluated at 2 years after transplantation. CKD was defined as a glomerular filtration rate (GFR) <90 mL/min/1.73 m2 using eGFR equations based on serum creatinine (SCr), cystatin C (CysC), and SCr plus CysC.

RESULTS

In our study, 9 (9.4%), according to Bedside Schwartz, 59 (76.6%), according to CKiD-eGFR-CysC, and 20 (26%) patients, according to CKiD-eGFR-SCr-CysC equations were identified with CKD. In cases identifies as CKD according to CysC, early development of acute kidney injury (AKI), post-transplant cytomegalovirus (CMV) reactivation and being >120 months during transplantation were found to be associated with the development of CKD.

CONCLUSION

We may be delayed in detecting CKD by calculating SCr-based formulas in allo-HSCT cases, which is a patient group where early diagnosis and treatment of CKD is very important.

Desfechos renais a longo prazo em crianças após transplante alogênico de células-tronco hematopoiéticas avaliados com equações de taxa de filtração glomerular estimada, níveis de creatinina e níveis de cistatina C

Resumo Antecedentes e objetivo: Com o uso generalizado do transplante alogênico de células-tronco hematopoiéticas (TCTH-alo), as complicações a longo prazo tornaram-se evidentes. O objetivo deste estudo foi determinar a prevalência e os fatores de risco do desenvolvimento de doença renal crônica (DRC) a longo prazo em pacientes submetidos a TCTH-alo na infância, e também investigar a superioridade das fórmulas de TFGe. Métodos: O presente estudo avaliou a DRC em pacientes que foram submetidos ao TCTH-alo. Analisamos as 94 crianças que receberam TCTH-alo na Universidade Ege em İzmir entre Agosto e Novembro de 2019. Os pacientes foram avaliados aos 2 anos após o transplante. A DRC foi definida como uma taxa de filtração glomerular (TFG) <90 mL/min/1,73 m2 usando equações de TFGe baseadas em creatinina sérica (CrS), cistatina C (CisC), e CrS mais CisC. Resultados: Em nosso estudo, 9 pacientes (9,4%), de acordo com a equação de Schwartz (à beira do leito), 59 (76,6%), de acordo com a equação DRC-TFGe-CisC, e 20 (26%) pacientes, de acordo com a equação DRC-TFGe-CrS-CisC, foram classificados com DRC. Quando a TFG é avaliada pela CisC, verificamos que o desenvolvimento precoce de lesão renal aguda (LRA), a reativação do citomegalovírus (CMV) pós-transplante e ter >120 meses durante o transplante foram associados ao desenvolvimento de DRC. Conclusão: Pode haver atraso na detecção da DRC quando usamos fórmulas baseadas em CrS em casos de TCTH-alo, que é um grupo de pacientes onde o diagnóstico e tratamento precoces da DRC são muito importantes.

Risk factors and occurrence of chronic kidney disease following acute kidney injury in Children

Background

Chronic kidney disease (CKD) is an irreversible progressive condition with diverse etiologies among which acute kidney injury (AKI) is increasingly being recognized as an important one.

Methods

This was a prospective observational study of pediatric intensive care unit (PICU) patients admitted with different etiologies, at a tertiary care hospital for children in Kashmir India, between October 2018 and September 2020. AKI was defined as an increase in absolute serum creatinine (SCr) ≥0.3 mg/dL or by a percentage increase in SCr 50% and/or by a decrease in urine output to <0.5 mL/kg/h for >6 hours (h). Besides analysis of AKI and associated PICU mortality, post-AKI patients after discharge were kept on follow-up for complete 1 year.

Results

From 119 enrolled patients with AKI with no preexisting risk factors, 5.6% (n = 8/119) developed CKD. The AKI-associated mortality rate after 48 h of PICU stay was 13.4% (n = 16/119). At time of discharge from hospital, elevated blood pressure (BP) (n = 5/8) and subnephrotic proteinuria (n = 3/8) were the statistically significant sequels of AKI (P value <0.001) for progression to CKD. After 3 months of follow-up, elevated BP (n = 7/8) and subnephrotic proteinuria (n = 3/8) were significantly associated with progression to CKD at 1 year (P < 0.005).

Conclusions

Occurrence of CKD after an attack of AKI was not uncommon and the risk of long-term consequences in the form of hypertension, proteinuria, and CKD is significant, which may be much higher than observed. It is prudent that all post-AKI PICU discharged patients must be monitored for the long-term consequences of AKI.

HMGB-1 and TGFβ-1 highlight immuno-inflammatory and fibrotic processes before proteinuria onset in pediatric patients with Alport syndrome

INTRODUCTION

Alport syndrome (ALP) is a rare genetic condition characterized by progressive involvement of the basal membranes and renal dysfunction. The purpose of the study was to evaluate urinary (u) and serum (s) levels of tumor growth factor (TGF)-beta(β) and high mobility group box (HMGB)-1 in ALP patients with normal renal function, albuminuria and proteinuria.

METHODS

A prospective, single-center study was performed with a follow-up period of 12 months, enrolling 11 pediatric ALP patients and 10 healthy subjects (HS). Normal values of serum creatinine, albuminuria and proteinuria, as well as unaltered estimated glomerular filtration rate (eGFR) were required at enrollment.

RESULTS

ALP patients had significantly higher levels of serum and urinary HMGB1 compared to HS. The same trend was observed for TGF-β1, with higher values in ALP patients than in HS. HMGB1 and TGF-β1 correlated with each other and with markers of renal function and damage. Urinary biomarkers did not correlate with eGFR, whereas sHMGB1 and sTGF-β1 were negatively related to filtration rate (r: - 0.66; p = 0.02, r: - 0.96; p < 0.0001, respectively). Using proteinuria as a dependent variable in a multiple regression model, only the association with sTGF-β1 (β = 0.91, p < 0.0001) remained significant.

CONCLUSIONS

High levels of HMGB1 and TGF-β1 characterized ALP patients with normal renal function, highlighting the subclinical pro-fibrotic and inflammatory mechanisms triggered before the onset of proteinuria. Further studies are needed to evaluate the role of HMGB1 and TGFβ-1 in ALP patients.

Relationship between High Blood Pressure and Microalbuminuria in Children Aged 6-9 Years in a South African Population

Though the association between high blood pressure and microalbuminuria is well established in adults, there is a paucity of information on microalbuminuria in children. This study investigated the relationship between high blood pressure and microalbuminuria in 6-9-year-old children. A cross-sectional study, which included 306 primary school children of age 6-9 years old from urban areas (n = 154) and rural areas (n = 152) of the Eastern Cape Province of South Africa, was conducted. Participants' anthropometric data were determined and systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) were measured and converted to BP percentiles for age, sex and height. Creatinine and albumin concentrations were assayed in early morning midstream urine and the albumin to creatinine ratio (ACR) was calculated. There was a 42.8% prevalence of elevated blood pressure/high blood pressure (E-BP/H-BP) and a 10.1% prevalence of microalbuminuria. Among the 131 children with E-BP/H-BP, 17 had elevated ACR with a prevalence of 13.95%. SBP and HR increased with increasing range of ACR and, furthermore, SBP was significantly (p < 0.05) higher in children with moderately and severely increased ACR. SBP was associated with ACR and increased SBP predicted microalbuminuria (R2 = 0.42, adj R2 = 0.039, B: 0.120, p = < 0.05). In conclusion, microalbuminuria was present in 6-9-year-old South African children of African Ancestry and a weak association was observed with SBP in children.

Clinical trial recommendations for potential Alport syndrome therapies

Alport syndrome is experiencing a remarkable increase in preclinical investigations. To proactively address the needs of the Alport syndrome community, as well as offer clarity for future clinical research sponsors, the Alport Syndrome Foundation hosted a workshop to generate consensus recommendations for prospective trials for conventional drugs. Opinions of key stakeholders were carefully considered, including those of the biopharmaceutical industry representatives, academic researchers, clinicians, regulatory agency representatives, and-most critically-patients with Alport syndrome. Recommendations were established for preclinical researchers, the use and selection of biomarkers, standards of care, clinical trial designs, trial eligibility criteria and outcomes, pediatric trial considerations, and considerations for patient engagement, recruitment, and treatment. This paper outlines their recommendations.

Effects of low skeletal muscle mass and sarcopenic obesity on albuminuria: a 7-year longitudinal study

We aimed to identify the association between low skeletal muscle, sarcopenic obesity, and the incidence of albuminuria in the general population using a longitudinal study. Data from 29,942 subjects who underwent two or more routine health examinations from 2006 to 2013 were retrospectively reviewed. Relative skeletal muscle mass was presented using the skeletal muscle mass index (SMI), a measure of body weight-adjusted appendicular skeletal muscle mass estimated by bioelectrical impedance analysis. The cumulative incidence of albuminuria was 981 (3.3%) during the 7-year follow-up period. The hazard ratio of incident albuminuria was 1.44 (95% CI: 1.22–1.71, p for trend <0.001) in the lowest SMI tertile relative to the highest SMI tertile after multivariable adjustment. After additionally adjusting for general and central obesity, the hazard ratio was 1.35 (95% CI: 1.13–1.61, p for trend = 0.001) and 1.30 (95% CI: 1.08–1.56, p for trend = 0.003), respectively. Furthermore, the risk of developing albuminuria was much higher in the sarcopenic obesity group (HR: 1.49, 95% CI: 1.21–1.81, p for trend <0.001) compared to the other groups. Sarcopenic obesity, as well as low skeletal muscle, may lead to albuminuria in general populations.

Individual and Environmental Factors Associated with Proteinuria in Korean Children: A Multilevel Analysis

Proteinuria is a significant sign of childhood renal disorders. However, little is known about how sociodemographic and environmental factors are related to the presence of proteinuria among children and adolescents. This paper focuses on the prevalence of proteinuria and its risk factors among children and adolescents. This study conducted a secondary analysis of data from the 2016 Sample Schools Raw Data of Health Examination for School Students (SSRDHESS). Data collected from 27,081 students who had undergone a health screening were analyzed using Chi-square tests, independent t-tests, and multilevel logistic regression analysis. The prevalence of proteinuria was higher in the thin group than in the normal weight group (adjusted odds ratio (aOR) = 1.77; 95% confidence interval (CI) = 1.34–2.33) and lower in the overweight/obese group (aOR = 0.64; 95% CI = 0.51–0.80). Additionally, those in metropolitan and small–medium sized cities had a proteinuria prevalence about 1.5-fold higher than that of those in rural areas (95% CI = 1.08–2.02, 95% CI = 1.19–1.92, respectively). Proteinuria was associated with environmental pollution, including smoking rate, ambient particulate matter and heavy metals in drinking water (aOR = 1.10; 95% CI = 1.01–1.20; aOR = 1.06; 95% CI = 1.01–1.11, aOR = 1.001; 95% CI = 1.0001–1.0015). These results suggest that to improve health management effectiveness, kidney disease prevention efforts for children and adolescents should focus on geographical area and environmental pollution, as well as body weight as individual factors.

Albuminuria: population epidemiology and concordance in Australian children aged 11-12 years and their parents

OBJECTIVES

To describe the distribution of albuminuria among Australian children aged 11-12 years and their parents, and assess its intergenerational concordance within parent-child dyads.

DESIGN

Population-based cross-sectional study (the Child Health CheckPoint), nested within the Longitudinal Study of Australian Children.

SETTING

Assessment centres (seven Australian cities and eight regional towns) and home visits across Australia, February 2015 to March 2016.

PARTICIPANTS

Of all participating CheckPoint families (n=1874), 1557 children (46.2% girls) and 1454 parents (85.5% mothers) provided random urine samples at the visit; samples from menstruating females were excluded.

OUTCOME MEASURES

Urine albumin-to-creatinine ratio (ACR) and its components (urine albumin and creatinine concentration); albuminuria was defined as an ACR ≥3.4 mg/mmol. Pearson's correlation coefficients and multivariable linear regression models assessed parent-child concordance, using log-transformed data due to skewing. Survey weights and methods were applied to account for the complex sample design.

RESULTS

The median ACR for children was 1.03 mg/mmol (IQR 0.65-1.97) and 1.01 mg/mmol (IQR 0.60-2.09) for adults. The median ACR was higher in girls (1.20, IQR 0.71-2.65) than boys (0.90, IQR 0.61-1.65) and in mothers (1.13, IQR 0.63-2.33) than fathers (0.66, IQR 0.41-1.05). Albuminuria was detected in 15.1% of children (girls 20.8%, boys 10.1%) and 13.5% of adults (15.1% mothers, 4.0% fathers) had albuminuria. There was a small correlation between parent and child ACR (Pearson correlation coefficient 0.06, 95% CI 0.01 to 0.12).

CONCLUSIONS

Albuminuria is common among Australian children and adults, which is of concern because it predicts risk for kidney and cardiovascular disease, and mortality. The weak concordance among intergenerational pairs for urine ACR suggests either that genetic heritability is low or that it becomes evident only at later offspring life stages.

Renal function and blood pressure are altered in adolescents born preterm

BACKGROUND

Preterm birth increases the risk of hypertension and kidney disease. However, it is unclear when changes in blood pressure (BP) and renal function become apparent and what role obesity and sex play. We hypothesized adolescents born preterm have higher BP and worse kidney function compared to term in an obesity- and sex-dependent manner.

METHODS

Cross-sectional analysis of 14-year-olds born preterm with very low birth weight (n = 96) compared to term (n = 43). We used generalized linear models to estimate the associations among preterm birth and BP, estimated glomerular filtration rate (eGFR), and ln (x) urinary albumin-to-creatinine ratio (ACR), stratified by overweight/obesity (OWO, body mass index (BMI) ≥ 85th percentile) and sex.

RESULTS

Compared to term, preterm-born adolescents had higher systolic blood pressure (SBP) and diastolic blood pressure (DBP) (adjusted β (aβ) 3.5 mmHg, 95% CI - 0.1 to 7.2 and 3.6 mmHg, 95% CI 0.1 to 7.0), lower eGFR (β - 8.2 mL/min/1.73 m², 95% CI - 15.9 to - 0.4), and higher ACR (aβ 0.34, 95% CI - 0.04 to 0.72). OWO modified the preterm-term difference in DBP (BMI < 85th percentile aβ 5.0 mmHg, 95% CI 0.7 to 9.2 vs. OWO 0.2 mmHg, 95% CI - 5.3 to 5.6) and ACR (OWO aβ 0.72, 95% CI 0.15 to 1.29 vs. BMI < 85th percentile 0.17, 95% CI - 0.31 to 0.65). Sex modified the preterm-term ACR difference (female aβ 0.52, 95% CI 0.001 to 1.04 vs. male 0.18, 95% CI - 0.36 to 0.72).

CONCLUSIONS

Prematurity was associated with higher BP and reduced renal function that were detectable in adolescence. OWO and sex may modify the strength of these relationships.

Albuminuria and glomerular filtration rate in obese children and adolescents

OBJECTIVE

To describe the frequency of albuminuria in overweight and obese children and adolescents and to relate it to the severity of obesity, pubertal staging, associated morbidities and the glomerular filtration rate.

METHOD

Cross-sectional study including 64 overweight and obese children and adolescents between 5 and 19 years of age.

DATA COLLECTED

weight, height, waist circumference and systemic arterial pressure.

LABORATORY TESTS

lipid profile; glycemia and insulin, used to calculate the Homeostasis Model Assessment (HOMA-IR); C-reactive protein; glutamic-pyruvic transaminase and albuminuria in an isolated urine sample (cutoff <30 mg/g). Creatinine was used to calculate the estimated glomerular filtration rate (eGFR, mL/min/1.73 m2).

RESULTS

The mean age was 11.6 ± 3.4 years, 32 (50%) and 29 (45.3%) were male and prepubertal. Forty-six (71.9%) had severe obesity. The frequency and median (min/max) of the observed values for albuminuria (> 30 mg/g) were 14 (21.9%) and 9.4 mg/g (0.70, -300.7 mg/g). The mean eGFR was 122.9 ± 24.7 mL/min/1.73 m2. There was no significant correlation between body mass index, pubertal staging, insulin and HOMA-IR with albuminuria values and neither with eGFR. Children with albuminuria tended to have higher values of diastolic blood pressure (75.0 ± 12.2 vs. 68.1 ± 12.4, p = 0.071).

CONCLUSION

Albuminuria, although frequent in children and adolescents with obesity, was not associated with other morbidities and the glomerular filtration rate in these patients.

Early renal damage among children living in the region of highest burden of chronic kidney disease of unknown etiology (CKDu) in Sri Lanka

Background

Chronic kidney disease of unknown origin (CKDu) in Sri Lanka is grouped with several other epidemics of similar nature across the world as Chronic Interstitial Nephritis in Agricultural Communities (CINAC). In CKDu endemic countries, the focus has mainly been on adults. We hypothesized that studying distribution and factors associated with elevated urine albumin to creatinine ratio (UACR), an early marker of kidney injury, among children living in a CKDu endemic area may provide important clues about the onset and progression of the disease.

Methods

This cross sectional study was performed in rural primary schools in North Central Province of Sri Lnaka, a CKDu high endemic region. Total of 2880 students aging 5 to 11 years from 67 schools were enrolled for urinalysis in a random spot urine sample. Bedside Schwartz formula was used to measure estimated glomerular filtration rate (eGFR) on all children with UACR > 30 mg/g in Polonnaruwa district and a group of age matched controls. A standard multiple linear regression using log transformed UACR as the dependent variable was performed. Mean eGFR were compared between UACR elevated group and controls using independent sample t test.

Results

Median UACR was 10.3 mg/g. Sex, ethnicity, history of having a chronic disease and age uniquely contributed to the multiple regression model which only explained 2.8% of the variance in the log of the UACR (p < 0.001). Only 15 (0.5%) had UACR> 300 mg/g while 8.2% (n = 236) had UACR between 30 to 300 mg/g and 89.8% (n = 203) of them did not have a chronic disease (Chi square 2.21, p = 0.091). Mean eGFR was significantly lower in the group with elevated UACR (88.9 mg/dl/1.73 m2, 95% CI for mean 86.4- 91.3) compared to group with normal UACR (93.7 mg/dl/1.73 m2,95% CI 91.1- 96.3) (t 2.7, p 0.007). Three out of the four students with eGFR less than 60 mg/dl/1.73 m2 had moderately elevated UACR.

Conclusion

This study provides evidence to suggest that children in CKDu endemic regions are having an early renal damage. This observation needs to be investigated further in order to understand the worldwide epidemic of CKDu.

Prevalence of Albuminuria in Children Living in a Rural Agricultural and Fishing Subsistence Community in Lake Chapala, Mexico

The occurrence of Chronic Kidney Disease (CKD) of unknown etiology in autochthonous child populations residing along the Lake Chapala lakeshore is endemic (Jalisco, México). The objective of this study was to determine the prevalence of albuminuria in the pediatric population and to measure the glomerular filtration rate in children with two positive albuminuria tests. Urinary albumin was measured in 394 children. Subjects with two or more positive albuminuria test donated blood samples for the determination of serum biomarkers. From a rural community with 565 children under the age of 17 years, 394 (69.7%) participated with first morning urine samples. A total of 180 children were positive (with two or more positive albuminuria tests). The prevalence of albuminuria among the children participating in the study was 45.7%. Of the 180 children with persistent albuminuria, 160 (88.9%) were tested for serum creatinine, urea, and cystatin C. The 68.1% of the children studied, were found in stages 3a and 3b of the Kidney Disease Improving Global Outcomes (KDIGO) classification (mean glomerular filtration rate (GFR) 51.9 and 38.4 mL/min/1.73 m² respectively). The lowest frequencies were for classifications 1 and 4. None of the subjects was classified as grade 5. The prevalence of albuminuria in children from this rural community is 3-5 times higher than reported in international literature. Regarding GFR, more than 50% of children studied are under 60 mL/min/1.73 m². It is a priority to find the causes of albuminuria and CKD in this Mexican region.

The population-based prevalence of albuminuria in children

OBJECTIVES

To determine the population-based prevalence of albuminuria in Australian children and validate any negative correlation with body mass index (BMI).

METHODS

Data from the Australian Health Survey 2011-2013 were used. This is a large-scale survey of the health of the Australian population, conducted by the Australian Bureau of Statistics, and uses a stratified, multistage area design with replicate weights attached to observations to allow for the derivation of accurate population estimates. We considered children aged 5-18 years, and defined albuminuria as an albumin-to-creatinine ratio (ACR) >30 mg/g (3.4 mg/mmol).

RESULTS

A total of 975 children provided urine samples for determination of ACR. The prevalence of albuminuria was 10.2% for males (95% confidence interval [CI] 6.1-14.2) and 15.5% for females (95% CI 10.7-20.3). After adjusting for age and gender, the odds ratio for albuminuria associated with being overweight or obese was 0.34 (95% CI 0.15-0.75). This relationship also held for waist-to-height ratio, where the adjusted odds ratio for each 0.1 increase was 0.46 (95% CI 0.26-0.82).

CONCLUSIONS

Albuminuria, using a measurement suitable for population-based and clinical screening, occurs in 12.8% of school-aged Australian children, and is less common in overweight and obese children.

Non-Traditional Risk Factors of Albuminuria in the Pediatric Population: A Scoping Review

The presence of albumin in urine has been used for more than four decades as a marker of renal and cardiovascular damage. Most of the information on this marker is related to adults. The prevalence of albuminuria in the pediatric population has been reported as being 2.2-12.8% in some countries. Most research in this field is related to albuminuria and diseases, such as diabetes and hypertension. Using the methodology described by Arksey and O'Malley in 2005, a scoping review was carried out to show that the presence of albumin in urine in the pediatric population might be associated with environmental, demographic, congenital, infectious, and non-infectious factors. The information collected is supported by 74 references present in PubMed. The results reveal the multiple causes associated with albuminuria in the pediatric population. This information can be very useful for clinical practice by adding knowledge about albuminuria behavior in children.

Albuminuria in Pediatric Patients With Adenotonsillar Hypertrophy

The relationship between intermittent nocturnal hypoxia and albuminuria in pediatric patients with adenotonsillar hypertrophy was evaluated in this prospective study. Fifty children with grade 3 to 4 adenotonsillar hypertrophy scheduled for adenoidectomy and/or adenotonsillectomy were selected for study group. Fifteen patients with adenotonsillar grade 1 to 2 or adenotonsillectomized subjects in a similar range of sex, age, and body mass index scheduled for other surgeries were selected for control group. All children were monitored using finger pulse oximeter during the night before surgery. At the day of surgery, first morning urine samples were sent to the laboratory for analysis of albuminuria.Albuminuria was determined in 8 (16%) patients in study group and 1 (6.7%) patient in control group. This difference between groups was determined not to be statistically significant (P > 0.05). None of the pulse oximetry parameters was also found to be associated with albuminuria statistically (P > 0.05). However, the adenoid grade was observed to be associated with albuminuria (P = 0.011).This study revealed no relationship between albuminuria and intermittent hypoxia in children, although previous studies have reported that intermittent hypoxia causes albuminuria in adults. On the contrary, the adenoid grade was found to be in association with albuminuria. The reason seems to be unclear because of the lack of studies investigating albuminuria in children with adenotonsillar hypertrophy. However, inflammatory mediators arising from adenoid tissue may cause increase in renal capillary permeability and urine albumin excretion.

AKI after pediatric cardiac surgery for congenital heart diseases-recent developments in diagnostic criteria and early diagnosis by biomarkers

Background

Acute kidney injury (AKI) after cardiac surgery in children with congenital heart disease is a common complication. AKI is also associated with high morbidity and mortality. The Kidney Diseases Improving Global Outcomes (KDIGO) criteria for AKI classification are now widely used for the definition of AKI. It is noteworthy that a statement about children was added to the criteria. Many studies aimed at finding useful biomarkers are now being performed by using these criteria. Clinicians should be aware of the recent progress in understanding AKI in children.

Main contents

Unlike adult patients, young age is one of the major risk factors for AKI in pediatric cardiac surgery. The mechanism of the development of AKI in children might be different from that in adults because the surgical procedure and CPB technique in pediatric patients are greatly different from those in adult patients.

There are many biomarkers for early detection of AKI, and some of them are widely used in hospitals. One of the major benefits of such biomarkers is the rapidness of expression for detecting increases in their expression levels. Neutrophil gelatinase-associated lipocalin, kidney injury molecule-1, cystatin C, and albumin have been investigated in some studies, and the usefulness of these biomarkers for detection of AKI and diagnosis of disease severity has been shown.

Although there are many interventions for preventing and treating AKI after cardiac surgery in children, there is still no specific effective treatment. Peritoneal dialysis is effective for only maintaining a negative fluid balance early after cardiac surgery. The long-term prognosis of AKI is an issue of interest. Although mortality and morbidity of AKI in the acute phase of disease remain high, the long-term condition in pediatric patients is relatively acceptable unlike in adults.

Conclusions

KDIGO criteria are advocated as a diagnostic tool for common perception. Early recognition and intervention for AKI can be achieved by using several biomarkers. Further studies are needed to establish effective treatment for AKI.

Prevalence of microalbuminuria and its associated cardiometabolic risk factors in Korean youth: Data from the Korea National Health and Nutrition Examination Survey

Background

Microalbuminuria is a known early predictive factor for renal and cardiovascular diseases, not only for patients with diabetes mellitus or hypertension but also in the general population. However, the prevalence and risk factors associated with microalbuminuria in Korean youth are unknown.

Objectives

The aims of this study are to evaluate the prevalence of microalbuminuria and the association between microalbuminuria and obesity or cardiometabolic risk factors in Korean children and adolescents without diabetes.

Methods

This study examines data obtained from the Korea National Health and Nutrition Examination Survey (between 2011 and 2014). It includes a total of 1,976 participants aged between 10 and 19 years (boys 1,128 and girls 848). Microalbuminuria was defined as a urine albumin-to-creatinine ratio (UACR) of ≥ 30 mg/g and < 300 mg/g. Association between microalbuminuria and the risk factors for cardiometabolic diseases including insulin resistance was evaluated.

Results

The prevalence of microalbuminuria was found to be 3.0% in Korean children and adolescents over this time period. The mean UACR for non-obese youth was significantly greater than that found in obese youth (3.2 ± 0.1 mg/g in the non-obese group vs. 2.1 ± 0.2 mg/g in the obese group; P < 0.001). In multiple logistic regression analysis, microalbuminuria was associated with hyperglycemia (OR 2.62, 95% CI 1.09–6.30) and hemoglobin A1c (OR 3.34, 95% CI 1.09–10.17) in the non-obese group and hypertension (OR 14.10, 95% CI 1.12–177.98) and HbA1c (OR 6.68, 95% CI 1.87–23.95) in the obese group.

Conclusions

The prevalence of microalbuminuria is not prominent in obese children and adolescents. Our findings demonstrated that the presence of hypertension and hyperglycemia was associated with microalbuminuria. Especially Hemoglobin A1c was associated with microalbuminuria in youths regardless of weight status. Microalbuminuria in pediatric population can be a helpful marker for the risk of cardiovascular disease.

Prevalence of Asymptomatic Microalbuminuria in HIV Positive Children in India

OBJECTIVE

To study the prevalence of covert or early renal involvement among human immunodeficiency virus (HIV) positive children.

METHODS

A cross-sectional observational study was carried out on 250 HIV positive children (2-18 y) on follow-up in a tertiary care hospital from January 2014 through June 2015. Those who met the study criteria were evaluated for microalbuminuria and glomerular and tubular dysfunctions.

RESULTS

Fifty-one out of two hundred fifty (20%) children were found to have microalbuminuria though none had any other evidence of renal dysfunction. The incidence of microalbuminuria in children on Anti Retroviral Therapy (ART) and those not on ART was 20% and 21% respectively. Neither was there any difference in those with a CD4 count ≤500/cu mm compared with those with counts >500/cu mm. However, the overall CD4 counts were significantly lower in children with microalbuminuria.

CONCLUSIONS

Microalbuminuria was detected in 20% of asymptomatic HIV positive children suggesting early glomerular dysfunction and need for regular screening and follow-up.

Maternal determinants of renal mass and function in the fetus and neonate

The impact of adverse maternal and early gestational issues, ranging from maternal-fetal interactions all the way through to premature birth, are recognized as having influence on the subsequent development of chronic diseases later in life. The development of chronic kidney disease (CKD) as a direct result of early life renal injury or a sequela of diseases such as hypertension or diabetes is a good model example of the potential impact that early life events may have on renal development and lifelong function. The global monetary and human resource cost of CKD is exorbitant. Socio-economic factors, along with other factors (genetic and environmental) may significantly influence the timing and display of phenotypic expression in fetuses and neonates at risk for developing CKD, yet very few of these factors are studied or well understood. In general our focus has been directed at treatment once CKD is established. This strategy has been and remains short-sighted and costly. Earlier understanding of the intrauterine determinants of renal mass development (i.e. environmental "biomes", poor maternal-fetal health, socio-economic factors impacting early life events, diet, access to value based health care and educational opportunities on disease evolution) may allow us an opportunity for earlier intervention. This article aims to provide some foundation for improved understanding of the maternal determinants of renal mass and function in the fetus and neonate.

The path to chronic kidney disease following acute kidney injury: a neonatal perspective

The risk of acute kidney injury (AKI) in hospitalized critically ill neonatal populations without primary renal disease continues to be high, in both term and premature infants. Observational studies have revealed high rates of chronic kidney disease (CKD) in survivors of neonatal AKI. Proposed mechanisms underlying the progression of CKD following AKI include nephron loss and hyperfiltration, vascular insufficiency and maladaptive repair mechanisms. Other factors, including prematurity and low birth weight, have an independent relationship with the development of CKD, but they may also be positive effect modifiers in the relationship of AKI and CKD. The large degree of heterogeneity in the literature on AKI in the neonatal population, including the use of various AKI definitions and CKD outcomes, has hampered the medical community's ability to properly assess the relationship of AKI and CKD in this vulnerable population. Larger prospective cohort studies with control groups which utilize recently proposed neonatal AKI definitions and standardized CKD definitions are much needed to properly quantify the risk of CKD following an episode of AKI. Until there is further evidence to guide us, we recommend that all neonates with an identified episode of AKI should have an appropriate longitudinal follow-up in order to identify CKD at its earliest stages.

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

OBJECTIVES

Acute kidney injury (AKI) is a severe complication of prematurity, with currently unknown consequences for renal function in childhood. The objective of this study was to search for signs of reduced nephron number in children aged 3-10 years who had been born preterm with neonatal AKI and compare this group to control children.

METHODS

IRENEO was a prospective, controlled study conducted in 2013 in Nantes University Hospital. Children who were born at less than 33 weeks gestational age (GA) and included in the LIFT cohort were eligible for entry. Twenty-five children with AKI (AKI-C) and 49 no-AKI children were matched on a propensity score of neonatal AKI and age. AKI was defined as a serum creatinine level higher than critical values: 1.6 mg/dl (GA 24-27 weeks), 1.1 mg/dl (28-29) and 1 mg/dl (GA 30-32). Renal function was evaluated during childhood.

RESULTS

Mean age of the children at the time of the study was 6.6 years. No difference in microalbuminuria, estimated glomerular filtration rate (GFR) or pulse wave velocity was observed between the two groups. Renal volume was lower in the AKI-C group (57 vs. 68; p = 0.04). In the entire cohort, 10.8 % had a microalbuminuria, and 23 % had a diminished GFR (median 79 ml/min/1.73 m²). The GFR was lower in children with very low birth weight of <1000 g (99 vs. 107 ml/min/1.73 m²; p = 0.04).

CONCLUSION

In children born preterm, neonatal AKI does not seem to influence renal function. However, independent ofAKI, a large proportion of very preterm infants, especially those with very low birth weight, presented with signs of nephron reduction, thus requiring follow-up with a nephrologist.

Practice recommendations for the monitoring of renal function in pediatric non-renal organ transplant recipients

The management of non-renal pediatric solid organ transplant recipients has become complex over the last decade with innovations in immunosuppression and surgical techniques. Post-transplantation follow-up is essential to ensure that children have functioning allografts for as long as possible. CKD is highly prevalent in these patients, often under recognized, and has a profound impact on patient survival. These practice recommendations focus on the early detection and management of hypertension, proteinuria, and renal dysfunction in non-renal pediatric solid organ transplant recipients. We present seven practice recommendations. Renal function should be monitored regularly in organ transplant recipients, utilizing assessment of serum creatinine and cystatin C. GFR should be calculated using the new Schwartz formula. Transplant physicians should also monitor blood pressure using automated oscillometric devices and confirm repeated abnormal measures with manual blood pressure readings and ambulatory 24-h blood pressure monitoring. Proteinuria and microalbuminuria should also be assessed regularly. Referrals to a pediatric nephrologist should be made for non-renal organ transplant recipients with repeated blood pressures >95th percentile using the Fourth Task Force reference intervals, microalbumin/creatinine ratio >32.5 mg/g (3.7 mg/mmol) creatinine on repeated testing and/or GFR <90 mL/min/1.73 m(2) .

Prevalence and distribution of (micro)albuminuria in toddlers

BACKGROUND

Microalbuminuria is common in the general adult population, with a prevalence of ∼7%, and is an independent indicator of renal and cardiovascular risks. Whether albuminuria is acquired during life (as a result of hypertension/diabetes) or is congenital and already present at birth is unknown. We studied the prevalence of microalbuminuria in toddlers and compared the distribution of albuminuria with that of the general adult population. In addition, we looked for possible associations between microalbuminuria and antenatal, postnatal and maternal factors.

METHODS

The urinary albumin concentration (UAC) was measured in 1352 children and the urinary albumin:creatinine ratio (UACR) in 1288 children from the Groningen Expert Center for Kids with Obesity (GECKO) Drenthe cohort (age range 20-40 months). Albuminuria distribution was compared with the albuminuria distribution in 40 854 participants of the general adult cohort of the Prevention of Renal and Vascular End stage Disease (PREVEND) study. Associations between albuminuria (expressed as UAC and UACR) and antenatal, postnatal and maternal factors were tested with linear regression analysis.

RESULTS

The median UAC in the GECKO study was 2.3 mg/L (5th-95th percentiles: 2.1-25.5) and in the PREVEND study it was 6.0 mg/L (2.3-28.6) (P distribution comparison 0.053). The prevalence of UAC ≥ 20 mg/L was 6.9% in the GECKO study and 7.8% in the PREVEND study (P = 0.195). The prevalence of UACR ≥ 30 mg/g in the GECKO study was 23.4%. UAC and UACR were lower in boys. UAC was not associated with other determinants, but UACR was associated with age and gestational diabetes.

CONCLUSIONS

The distribution of UAC and the prevalence of UAC > 20 mg/L in toddlers and in the young general adult population are comparable. These findings suggest that microalbuminuria is a congenital condition that may predispose to a higher cardiovascular risk later in life.

Early-life course socioeconomic factors and chronic kidney disease

Kidney failure or ESRD affects approximately 650,000 Americans, whereas the number with earlier stages of CKD is much higher. Although CKD and ESRD are usually associated with adulthood, it is likely that the initial stages of CKD begin early in life. Many of these pathways are associated with low birth weight and disadvantaged socioeconomic status (SES) in childhood, translating childhood risk into later-life CKD and kidney failure. Social factors are thought to be fundamental causes of disease. Although the relationship between adult SES and CKD has been well established, the role of early childhood SES for CKD risk remains obscure. This review provides a rationale for examining the association between early-life SES and CKD. By collecting data on early-life SES and CKD, the interaction with other periods in the life course could also be studied, allowing for examination of whether SES trajectories (eg, poverty followed by affluence) or cumulative burden (eg, poverty at multiple time points) are more relevant to lifetime CKD risk.

Obese children and adolescents have elevated nighttime blood pressure independent of insulin resistance and arterial stiffness

BACKGROUND

Insulin resistance has been related to elevated blood pressure (BP) in obese children and may adversely affect the vasculature by arterial stiffening. The objective was to investigate whether daytime and nighttime BP were elevated and related to insulin resistance and arterial stiffness in obese children and adolescents.

METHODS

Ninety-two obese patients aged 10-18 years were compared with 49 healthy control individuals. Insulin resistance was measured as the homeostatic assessment model (HOMA), and arterial stiffness was measured as carotid-femoral pulse wave velocity (cfPWV).

RESULTS

Mean ± SD daytime systolic BP (SBP) (obese: 125±8.3mm Hg; control: 121±10.1mm Hg; P = 0.03) and nighttime SBP (obese: 108±10.7mm Hg; control: 102±8.2mm Hg; P = 0.0001) were higher in the obese group when compared with the control group. No difference was found in daytime diastolic BP (DBP), whereas nighttime DBP (obese: 60±6.6mm Hg; control: 57±4.8mm Hg; P = 0.001) and night-to-day BP ratios were higher in the obese group. Nighttime SBP was related to BMI z score (β = 6.0; 95% confidence interval (CI) = 2.9-9.1; P = 0.0002) and waist/height ratio (β = 36.7; 95% CI = 5.6-67.9; P = 0.02) in the obese group. HOMA index (obese: median = 3.7, interquartile range (IQR) = 2.3-6.0; control: median = 2.6, IQR = 1.8-3.4; P = 0.002) was higher, whereas cfPWV (obese: 4.8±0.8 m/s; control: 5.1±0.6 m/s; P = 0.03) was lower in the obese group. CfPWV was not related to logHOMA index. In multiple regression analyses, the higher nighttime BP in the obese group was independent of logHOMA and cfPWV.

CONCLUSIONS

Obese children had a higher nighttime BP when compared with the control group independently of insulin resistance and arterial stiffness. No relationship was found between insulin resistance and arterial stiffness. CLINICAL TRIAL REGISTRATION Clinicaltrials.gov identifier NCT01310088.

The utility of microalbuminuria measurements in pediatric burn injuries in critical care

PURPOSE

Microalbuminuria, as measured by urinary albumin-creatinine ratios (ACRs), has been shown to be a marker of systemic inflammation and an indicator of the potential severity of trauma and critical illness. Severe pediatric burns represent the best model in which to investigate the clinical utility of microalbuminuria. This study aims to ascertain whether ACR measurements have any role in predicting the severity or the intensive care requirements in the critically unwell pediatric burn population.

MATERIALS AND METHODS

A retrospective observational study was undertaken within a regional burn center with a dedicated 8-bed burn intensive care unit (ICU). This looked at 8 years of consecutive pediatric burns requiring intensive care support-a total of 63 patients after exclusions. Daily urinary ACR measurements were acquired from all patients.

RESULTS

All patients had greater than or equal to 1 ACR measurement out with the reference range, and only 8% (5/63) presented to the ICU with a normal ACR. The median day for the peak ACR measurement was day 4. The relative lack of mortalities (3/63) precluded adequate correlations between ACR and outcomes. Peak and mean ACR values correlate well with length of ICU stay, and the peak ACR also correlates with total length of hospital stay and severity of burn injury as measured by total body surface area burnt and number of organ systems requiring support. No significant differences were found when the patients were stratified by age. The peak ACR measurement was found to be independently predictive of the length of the ICU stay. As such, we have created a predictive model to prove that an ACR that remains less than 12 mg/mmol is predicative of an ICU stay of less than or equal to 7 days.

CONCLUSIONS

The clinical utilities of ACR measurements are demonstrated by their correlation with the severity of injury, length of ICU stay, and requirements for multiple organ support. Albumin-creatinine ratios raised over certain thresholds highlight to the clinician the need for closer observation and the potential deterioration of patients.

Kidney size and function in a multi-ethnic population-based cohort of school-age children

BACKGROUND

Subclinical impaired kidney growth and function in childhood may lead to kidney diseases and high blood pressure in adulthood. We assessed the cross-sectional associations of childhood characteristics with kidney size and function in a multi-ethnic cohort.

METHODS

This study was embedded in a population-based cohort study of 6,397 children with a median age of 6.0 years.Kidney volume, creatinine and cystatin C blood levels, microalbuminuria and blood pressure were measured, and glomerular filtration rate (GFR) was estimated.

RESULTS

Childhood anthropometrics were positively associated with kidney volume, creatinine level and blood pressure (all p < 0.05). We observed ethnic differences in all kidney size and function measures (all p < 0.05). Children with smaller kidneys had higher creatinine and cystatin C blood levels, leading to a lower estimated GFR [difference 5.68 ml/min/1.73 m2 (95% confidence interval 5.14-6.12) per 1 standard deviation increase in kidney volume]. Larger kidney volume was associated with an increased risk of microalbuminuria.

CONCLUSIONS

Childhood kidney volume and function are influenced by body mass index and ethnicity. Kidney volume is related with kidney function but not with blood pressure. These results may help to identify individuals at risk for kidney disease in an early stage.

The role of albuminuria in the follow-up of HIV-infected pediatric patients

BACKGROUND

In HIV-infected adults, elevated albumin has been associated with increased inflammatory activity, HIV-related nephropathy, and type 2 diabetes. Data on albuminuria in HIV-infected children are very scarce, and guidelines do not include routine determination of urinary albumin/creatinine ratio in this population.

METHODS

We performed a cross-sectional study in a cohort of HIV-infected pediatric patients. Urinary protein/creatinine and albumin/creatinine ratios and hematuria were determined from at least three morning urine samples, and glomerular filtration rate (GFR) was estimated from creatinine levels. Persistent renal damage was defined according to the presence of at least two sequentially abnormal values in one of the parameters. The relationship between renal damage, HIV-related variables, and metabolic comorbidities (dyslipidemia, fat redistribution, glucose intolerance, hypertension) was investigated.

RESULTS

Symptom-free renal damage was observed in 13 of 68 patients (19.1%) and mainly consisted of persistent proteinuria (17.6%); glomerular proteinuria was twice as prevalent as tubular proteinuria. GFR were normal in all cases. No relationship between renal markers and HIV-related variables or metabolic comorbidities was observed.

CONCLUSIONS

Mild proteinuria affected approximately one fifth of patients in our cohort. The determination of albuminuria allowed the differentiation between glomerular and tubular proteinuria, although no relationship with metabolic comorbidities was observed.

Fetal and infant growth patterns and kidney function at school age

Low birth weight is associated with ESRD. To identify specific growth patterns in early life that may be related to kidney function in later life, we examined the associations of longitudinally measured fetal and infant growth with kidney function in school-aged children. This study was embedded in a population-based prospective cohort study among 6482 children followed from fetal life onward. Fetal and childhood growth was measured during second and third trimesters of pregnancy, at birth, and at 6, 12, 24, 36, and 48 months postnatally. At the age of 6 years, we measured kidney volume by ultrasound. GFR was estimated using blood creatinine levels. Higher gestational age-adjusted birth weight was associated with higher combined kidney volume and higher eGFR (per 1 SD score increase in birth weight; 1.27 cm(3) [95% confidence interval, 0.61 to 1.93] and 0.78 ml/min per 1.73 m2 [95% CI, 0.16 to 1.39], respectively). Fetal weight, birth weight, and weight at 6 months were positively associated with childhood kidney volume, whereas higher second trimester fetal weight was positively associated with higher GFR (all P values<0.05). Fetal and childhood lengths were not consistently associated with kidney function. In this cohort, lower fetal and early infant weight growth is associated with smaller kidney volume in childhood, whereas only lower fetal weight growth is associated with lower kidney function in childhood, independent of childhood growth. Whether these associations lead to an increased risk of kidney disease needs to be studied further.

Evaluation of hypertension in children

Hypertension is an important public health problem, and increasingly children are being diagnosed with primary hypertension. As the list of secondary causes of hypertension is extensive, pediatric practitioners increasingly need to decide on investigations needed for evaluating children presenting with high blood pressure. The differentiation between primary and secondary hypertension is paramount to understanding this important health issue, since many forms of secondary hypertension require specific treatment. The review evaluates the current available guidelines and practice patterns for evaluating children with elevated blood pressure. The review also aims to provide a framework for cost-effective evaluation strategies for children with elevated blood pressure based on current recommendations and evidence.

Short-term gestation, long-term risk: prematurity and chronic kidney disease

Thanks to remarkable advances in neonatal intensive care, infants who once had little chance for survival can now enter adulthood. Yet the consequences of premature birth or low birth weight (LBW) on nephrogenesis, final nephron number, and long-term kidney function are unclear. This review focuses on the theory, experimental evidence, and observational data that suggest an increased risk of chronic kidney disease (CKD) for infants born prematurely. Many premature and LBW infants begin life with an incomplete complement of immature nephrons. They are then exposed to a variety of external stressors that can hinder ongoing kidney development or cause additional nephron loss such as hemodynamic alterations, nephrotoxic medications, infections, and suboptimal nutrition. Acute kidney injury, in particular, may be a significant risk factor for the development of CKD. According to Brenner's hypothesis, patients with decreased nephron number develop hyperfiltration that results in sodium retention, hypertension, nephron loss, and CKD due to secondary focal segmental glomerulosclerosis. Because the risk of CKD in premature and LBW infants has not been accurately determined, there are no evidence-based recommendations for screening or management. Yet with the first generation of infants from the surfactant era only now reaching adulthood, it is possible that there is already an unrecognized epidemic of CKD. We suggest individualized, risk-based assessments of premature and LBW infants due to the increased risk of CKD and call for additional research into the long-term risk for CKD these infants face.

Assessment of microalbuminuria for early diagnosis and risk prediction in dengue infections

BACKGROUND

Dengue is the most important arboviral infection of humans. Following an initial febrile period, a small proportion of infected patients develop a vasculopathy, with children at particular risk for severe vascular leakage and shock. Differentiation between dengue and other common childhood illnesses is difficult during the early febrile phase, and risk prediction for development of shock is poor. The presence of microalbuminuria is recognized as a useful early predictor for subsequent complications in a number of other disorders with vascular involvement. Significant proteinuria occurs in association with dengue shock syndrome and it is possible that early-phase microalbuminuria may be helpful both for diagnosis of dengue and for identification of patients likely to develop severe disease.

METHODOLOGY/PRINCIPAL FINDINGS

We measured formal urine albumin to creatinine ratios (UACRs) in daily samples obtained from a large cohort of children with suspected dengue recruited at two outpatient clinics in Ho Chi Minh City, Vietnam. Although UACRs were increased in the 465 confirmed dengue patients, with a significant time trend showing peak values around the critical period for dengue-associated plasma leakage, urine albumin excretion was also increased in the comparison group of 391 patients with other febrile illnesses (OFI). The dengue patients generally had higher UACRs than the OFI patients, but microalbuminuria, using the conventional cutoff of 30 mg albumin/g creatinine discriminated poorly between the two diagnostic groups in the early febrile phase. Secondly UACRs did not prove useful in predicting either development of warning signs for severe dengue or need for hospitalization.

CONCLUSION/SIGNIFICANCE

Low-level albuminuria is common, even in relatively mild dengue infections, but is also present in many OFIs. Simple point-of-care UACR tests are unlikely to be useful for early diagnosis or risk prediction in dengue endemic areas.

Microalbuminuria in children with primary and white-coat hypertension

Microalbuminuria serves as an early marker of hypertension-related renal damage in adults. However, data on the prevalence of microalbuminuria in paediatric hypertensive patients in general and in children with white-coat hypertension (WCH) specifically are lacking. The aim of our study was to investigate the prevalence of microalbuminuria in children with primary hypertension (PH) and WCH, respectively. This was a retrospective case review of children with PH and WCH treated at three paediatric nephrology centres. Untreated children with either form of hypertension for whom measurements of urinary albumin excretion (UAE) had been performed were enrolled in the study. The study cohort comprised 52 children (39 boys) with hypertension (26 children with PH, 26 with WCH). Microalbuminuria (>3.2 mg/mmol creatinine) was present in 20% of children with PH and none of the children with WCH (p < 0.01). Children with PH had a higher median UAE than those with WCH (1.27 ± 1.92 vs. 0.66 ± 0.46 mg/mmol creatinine, p < 0.05). Based on these results, we suggest that children with PH have an increased prevalence of microalbuminuria, while children with WCH show no signs of hypertension-related renal damage.

Long-term risk of CKD in children surviving episodes of acute kidney injury in the intensive care unit: a prospective cohort study

BACKGROUND

The development of standardized acute kidney injury (AKI) definitions has allowed for a better understanding of AKI epidemiology, but the long-term renal outcomes of AKI in the pediatric critical care setting have not been well established. This study was designed to: (1) determine the incidence of chronic kidney disease (CKD) in children 1-3 years after an episode of AKI at a tertiary-care pediatric intensive care unit (ICU), (2) identify the proportion of patients at risk of CKD, and (3) compare ICU admission characteristics in those with and without CKD.

DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

Patients admitted to the British Columbia Children's Hospital pediatric ICU from 2006-2008 with AKI, as defined by AKI Network (AKIN) criteria. Surviving patients, most with short-term recovery from their AKI, were assessed at 1, 2, or 3 years after AKI.

PREDICTORS

Severity of AKI as defined by AKIN and several ICU admission characteristics, including demographics, diagnosis, severity of illness, and ventilation data.

OUTCOMES & MEASUREMENTS

CKD was defined as the presence of albuminuria and/or glomerular filtration rate (GFR) < 60 mL/min/1.73 m2. Being at risk of CKD was defined as having a mildly decreased GFR (60-90 mL/min/1.73 m2), hypertension, and/or hyperfiltration (GFR ≥ 150 mL/min/1.73 m2).

RESULTS

The proportion of patients with AKI stages 1, 2, and 3 were 44 of 126 (35%), 47 of 126 (37%), and 35 of 126 (28%), respectively. The number of patients with CKD 1-3 years after AKI was 13 of 126 (10.3% overall; 2 of 44 [4.5%] with stage 1, 5 of 47 [10.6%] with stage 2, and 6 of 35 [17.1%] with stage 3; P = 0.2). In addition, 59 of 126 (46.8%) patients were identified as being at risk of CKD.

LIMITATIONS

Several patients identified with AKI were lost to follow-up, with the potential of underestimating the incidence of CKD.

CONCLUSIONS

In tertiary-care pediatric ICU patients, ∼10% develop CKD 1-3 years after AKI. The burden of CKD in this population may be higher with further follow-up because several patients were identified as being at risk of CKD. Regardless of the severity of AKI, all pediatric ICU patients should be monitored regularly for long-term kidney damage.

Microalbuminuria: causes and implications

Management strategies are increasingly focused on tackling the increasing burden of cardiovascular disease worldwide. Microalbuminuria is a powerful predictor of cardiovascular disease and mortality in adults. This holds true in the general adult population but is particularly recognized in those with diabetes, where it identifies those likely to develop progressive atherosclerotic vascular disease and renal impairment. The atherosclerotic process begins in childhood with likely consequences in later life. In-depth understanding of the mechanisms through which microalbuminuria occurs holds promise for designing therapies to arrest its development in the future. Microalbuminuria arises from increased leakage of albumin through the complex glomerular sieve known as the glomerular filtration barrier. This requires changes in the physio-chemical properties of components of this barrier. However, the increased glomerular permeability confirmed in disease does not necessarily correlate with recognized histological changes in the glomerulus, suggesting that perhaps more subtle ultrastructural changes may be relevant. The epidemiology of microalbuminuria reveals a close association between systemic endothelial dysfunction and vascular disease, also implicating glomerular endothelial dysfunction in microalbuminuria. This review discusses the mechanisms of microalbuminuria in disease, particularly the emerging role of the glomerular endothelium and its glycocalyx, and examines its implications for cardiovascular disease in the pediatric population.

Chronic kidney disease and albuminuria in children with sickle cell disease

BACKGROUND AND OBJECTIVES

Sickle cell nephropathy begins in childhood and may progress to renal failure. Albuminuria is a sensitive marker of glomerular damage that may indicate early chronic kidney disease (CKD).

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The aims of this study were to determine the cross-sectional prevalence and clinical correlates of albuminuria and CKD among children with sickle cell disease (SCD). Over a 10-year period (1995 to 2005) 410 pediatric SCD patients ages 2 to 21 years were enrolled: 261 with hemoglobin SS (HbSS) or HbSβ(0) thalassemia (HbSβ(0)) and 149 with HbSC or HbSβ(+) thalassemia (HbSβ(+)). The albumin/creatinine ratio (ACR) of spot-urine specimens and serum creatinine were measured; abnormal albuminuria was defined as urinary ACR ≥ 30 mg/g.

RESULTS

The prevalence of abnormal albuminuria was 20.7% (23.0% in HbSS/HbSβ(0), 16.8% in HbSC/HbSβ(+)). Among HbSS/HbSβ(0), abnormal albuminuria was associated with increasing age and lower baseline hemoglobin. GFR, estimated in 189 patients using the updated Schwartz formula, correlated negatively with age (r = -0.27, P = 0.0002). CKD defined according to the Kidney Disease: Improving Global Outcomes study was present in 26.5% (50 of 189) of patients: stage 1 in 27 (14.8%) and stage 2 in 22 (11.6%). In multivariate analysis, age and HbSC/HbSβ(+) genotype were associated with CKD.

CONCLUSIONS

This is the first study to stage CKD in children with SCD and highlights a high prevalence of albuminuria and glomerular injury early in life. Detecting CKD in childhood could allow for earlier intervention and prevention of renal failure in adulthood.

Urinary matrix metalloproteinase activities: biomarkers for plaque angiogenesis and nephropathy in diabetes

Diabetic complications of nephropathy and accelerated atherosclerosis are associated with vascular remodeling and dysregulated angiogenesis. Matrix metalloproteinases (MMP) modify extracellular matrix during vascular remodeling and are excreted in urine of patients with vascular malformation or tumor angiogenesis. We hypothesized that urinary MMP activities would be sensitive biomarkers for vascular remodeling in diabetic complications. Activities of MMP-2, MMP-9, and its complex with neutrophil gelatinase-associated lipocalin (NGAL/MMP-9) were measured by substrate gel zymography in urine from nondiabetic (ND) and type 1 diabetic (T1D) rodents that were susceptible to both T1D-induced plaque angiogenesis and nephropathy, or nephropathy alone. Additionally, these urine activities were measured in ND and T1D adolescents. Urinary MMP-9, MMP-2, and NGAL/MMP-9 activities were increased and more prevalent in T1D compared with ND controls. Urinary MMP-2 activity was detected in mice with T1D-induced plaque neovascularization. In nephropathy models, urinary NGAL/MMP-9 and MMP-9 activities appeared before onset of albuminuria, whereas MMP-2 was absent or delayed. Finally, urinary MMP activities were increased in adolescents with early stages of T1D. Urinary MMP activities may be sensitive, noninvasive, and clinically useful biomarkers for predicting vascular remodeling in diabetic renal and vascular complications.

Microalbuminuria in the paediatric age: current knowledge and emerging questions

The prevalence of microalbuminuria (MA) in children and adolescents differs from the one in adults, and it is estimated to be about 5.7-7.3% in boys and 12.7-15.1% in girls. The percentage is greater in smaller age group, whereas a positive association is found between albumin excretion rate and pubertal development stage in nondiabetic subjects. The data so far suggest that impairment of glucose metabolism, obesity-related proatherosclerotic pathways and the impact of haemodynamic load constitute major determinants of albuminuria development in the early years of life. In everyday practice if persistent MA is present at a young age, especially in the setting of diabetes, further investigation of cardiovascular risk factors, a more careful follow-up and dietary/lifestyle interventions are needed.

CONCLUSION

Although the significance of MA in paediatric essential hypertension has yet to be determined, its role in diabetic children and adolescents is established and albuminuria assessment has been utilized as a screening test for the presence of diabetes-related kidney disease.

Decreased urine albumin:creatinine ratios in infants of diabetic mothers: does exposure to diabetic pregnancies alter fetal renal development?

Offspring of diabetic mothers experience an increased risk for type 2 diabetes but it is not known whether diabetic pregnancies also confer a higher inter-generational risk for diabetic complications. Because microalbuminuria is a sensitive indicator of glomerular damage, we compared the urine albumin:creatinine ratios (ACRs) between 65 infants of diabetic mothers (InfDM+) and 59 infants of non-diabetic mothers (InfDM−), and repeated the comparisons in 21 InfDM+ and 19 InfDM− when children were 5–19 months old. ACRs were higher among neonates compared with normal reference values for adults, but declined with increasing age. The only independent predictor of higher ACRs in a logistic regression model (⩾13 mg/mmol v. <13 mg/mmol) was the presence of delivery complications (odds ratio 2.95; P = 0.015). Neither high nor low birth weight was associated with higher neonatal ACRs. The most unique finding of the study was that InfDM+ had significantly lower ACRs than InfDM− [mean = 12.9 (median = 6.0) v. mean = 16.6 (median = 11.5), respectively at P = 0.05] even after adjusting for other variables using logistic regression (odds ratio 0.25; P = 0.001). In contrast, by 5–19 months, there was a trend toward higher ACRs among InfDM+ compared with InfDM− [mean = 6.3 mg/mmol (median = 1.9) v. mean = 3.0 mg/mmol (median = 2.5), respectively at P = 0.25]. Lower ACRs in InfDM+ may be due to developmental changes in fetal kidneys induced by hyperinsulinemia. Although the implications of this observation are unclear, it is possible that exposure to a diabetic intrauterine environment might influence the later risk for renal disease.

Microalbuminuria in normal Korean children

PURPOSE

Although microalbuminuria is known as a predictor of clinical nephropathy and cardiomyopathy, few studies have investigated the incidence and reference range of microalbuminuria in healthy children. This study aimed to establish a reference range and to study the age-related trend for spot urine microalbumin/creatinine ratio in a Korean pediatric population.

MATERIALS AND METHODS

352 healthy children were studied from July 2007 through March 2010. Height, weight, serum creatinine, spot urine microalbumin/creatinine ratio, and glomerular filtration rate (GFR) were obtained for each subject. We divided the study population into 5 groups according to age, and compared the spot urine microalbumin/creatinine ratio with other variables using one-way analysis of variance (ANOVA), regression analysis and Pearson's correlation analysis.

RESULTS

In this study, the data showed that the spot urine microalbumin/creatinine ratio decreased with age: 1-12 months, 22.72 ± 13.80 mg/mmol (2SD: 3.33-54.40 mg/mmol); 13-28 months, 16.34 ± 9.58 mg/mmol (2SD: 3.16-35.19 mg/mmol); 29-48 months, 13.12 ± 9.74 mg/mmol (2SD: 3.01-41.57 mg/mmol); 4-6 years, 10.58 ± 8.13 mg/mmol (2SD: 0.00-30.19 mg/mmol); and 7-19 years, 5.13±5.44 mg/mmol (2SD: 0.45-14.45 mg/mmol). The spot urine microalbumin/creatinine ratio showed correlation with age, height, height z-score, weight, weight z-score, GFR, body mass index (BMI) and body surface area (BSA).

CONCLUSION

The spot urine microalbumin/creatinine ratio in normal Korean children decreased with age. This ratio could potentially be used to establish reference ranges and cutoff values for Korean children and to predict nephropathy and cardiomyopathy.