The relationship between body weight, cystatin C and serum creatinine in neonates

An Exploratory Review on the Potential of Artificial Intelligence for Early Detection of Acute Kidney Injury in Preterm Neonates

A preterm birth is a live birth that occurs before 37 completed weeks of pregnancy. Approximately 15 million babies are born preterm annually worldwide, indicating a global preterm birth rate of about 11%. Up to 50% of premature neonates in the gestational age (GA) group of <29 weeks' gestation will develop acute kidney injury (AKI) in the neonatal period; this is associated with high mortality and morbidity. There are currently no proven treatments for established AKI, and no effective predictive tool exists. We propose that the development of advanced artificial intelligence algorithms with neural networks can assist clinicians in accurately predicting AKI. Clinicians can use pathology investigations in combination with the non-invasive monitoring of renal tissue oxygenation (rSO2) and renal fractional tissue oxygenation extraction (rFTOE) using near-infrared spectroscopy (NIRS) and the renal resistive index (RRI) to develop an effective prediction algorithm. This algorithm would potentially create a therapeutic window during which the treating clinicians can identify modifiable risk factors and implement the necessary steps to prevent the onset and reduce the duration of AKI.

Comparison of different neonatal illness severity scores in predicting mortality risk of extremely low birth weight infants

To compare different illness severity scores in predicting mortality risk of extremely low birth weight infants (ELBWI). From January 1st, 2019 to January 1st, 2020, all ELBWI admitted in the Children's Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital and the First Affiliated Hospital of Nanjing Medical University were included in the study. ELBWI with admission age ≥1 h, gestational age ≥37 weeks and incomplete data required for scoring were excluded. The clinical data were collected, neonatal critical illness score (NCIS), score for neonatal acute physiology version Ⅱ (SNAP-Ⅱ), simplified version of the score for neonatal acute physiology perinatal extension (SNAPPE-Ⅱ), clinical risk index for babies (CRIB) and CRIB-Ⅱ were calculated. The scores of the fatal group and the survival group were compared, and the receiver operating characteristic (ROC) curve was used to evaluate the predictive value of the above illness severity scores for the mortality risk of ELBWI. Pearson correlation analysis was used to analyze the correlation between illness scores and birth weight, illness scores and gestational age. A total of 192 ELBWI were finally included, of whom 114 cases survived (survival group) and 78 cases died (fatal group). There were significant differences in birth weight, gestational age and Apgar scores between fatal group and survival group (all <0.01). There were significant differences in NCIS, SNAP-Ⅱ, SNAPPE-Ⅱ, CRIB and CRIB-Ⅱ between fatal group and survival group (all <0.01). The CRIB had a relatively higher predictive value for the mortality risk. Its area under the ROC curve (AUC) was 0.787, the sensitivity was 0.678, the specificity was 0.804, and the Youden index was 0.482. The scores of NCIS, SNAP-Ⅱ, SNAPPE-Ⅱ, CRIB and CRIB-Ⅱ were significantly correlated with birth weight and gestational age (all <0.05). The correlation coefficients of CRIB-Ⅱ and CRIB with birth weight and gestational age were relatively large, and the correlations coefficients of NCIS with birth weight and gestational age were the smallest (0.191 and 0.244, respectively). Among these five illness severity scores, CRIB has better predictive value for the mortality risk in ELBWI. NCIS, which is widely used in China, has relatively lower sensitivity and specificity, and needs to be further revised.

Cystatin C Concentration During the First Three Postnatal Days in Healthy Term Newborns

OBJECTIVE

Cystatin C (Cys-C) concentration has not been examined sufficiently among healthy newborn population, particularly in terms of reference values. This study aimed to establish gender-, postnatal age- and birth weight-specific Cys-C concentration for healthy term newborns. Its objective was also to examine if there were any differences between our measured concentration and the reference interval established by the CALIPER study.

METHODS

Serum samples from a total of 90 healthy term newborns were used to determine Cys-C concentration. Cys-C was measured within first three days of birth using particle-enhanced turbidimetric immunoassay (PETIA) on the Architect plus ci8200 analyzer.

RESULTS

Median concentration of the Cys-C was 2.05 mg/L. There were no statistically significant differences in Cys-C concentration regarding gender (p=0.779), birth weight (p=0.505), postnatal age (p=0.512) or Apgar score (p=0.799). The value of the 2.5th and 97.5th percentile for Cys-C concentrations for girls was 0.93-3.15 mg/L and for boys it was 1.5-3.36 mg/L.

CONCLUSION

Cys-C concentration in healthy term newborns does not depend on gender, birth weight, postnatal age, or Apgar score. Our measured concentration range of CyS-C in healthy newborns turned out to be slightly wider than the interval determined in the CALIPER study.

The influence of hyperbilirubinemia on indexes of kidney function in neonates

BACKGROUND

To study the influence of hyperbilirubinemia on indexes of neonatal kidney function.

METHODS

A prospective cohort study was conducted September 2019 to March 2020 in Neonatology Department of Xuzhou Central Hospital. Neonates with gestational age ≥ 35 weeks and aged ≤ 7 days were included and divided into mild, moderate, and severe groups according to total serum bilirubin level. Epidemiologic and demographic data and daily urine output were recorded. Total serum bilirubin, serum creatinine, serum cystatin C, serum neutrophil gelatinase-associated lipocalin (NGAL), urine NGAL, and kidney injury molecule-1 were tested before and 12~18 h after phototherapy. Parameters of kidney function were compared between groups.

RESULTS

Fifty-three, 52, and 49 neonates were included in the mild, moderate, and severe groups, respectively. Urine NGAL was higher in severe (1.36 ± 0.24 μg/L) compared to moderate (1.22 ± 0.19 μg/L) and mild groups (1.16 ± 0.19 μg/L), and differences were statistically significant (P = 0.004 and < 0.001, respectively). Urine NGAL was not significantly different between moderate and mild groups (P > 0.05). No significant differences in other kidney function indexes were observed between the three groups (all P > 0.05). Significant reduction in urine NGAL levels 12~18 h after stopping phototherapy was found in severe group ((1.17 ± 0.28) μg/L vs. (1.35 ± 0.23) μg/L, P < 0.001). Urine NGAL positively correlated with total serum bilirubin (r = 0.575, P < 0.001). Among all cases, neither serum creatinine nor daily urine output met neonatal acute kidney injury diagnostic criteria.

CONCLUSION

Severe hyperbilirubinemia may temporarily impair renal tubular reabsorption functions in full-term and near-term neonates, which is likely reversible. However, it has little effect on glomerular filtration function. A higher resolution version of the Graphical abstract is available as Supplementary information.

The progression of serum cystatin C concentrations within the first month of life after preterm birth-a worldwide systematic review

Multiple single-center studies have examined the progression of kidney function biomarkers such as serum cystatin C (Cys C) in the first 30 days of life (DOL) after preterm birth, but from different ethnicities and in different gestational ages (GA), without a functional summary available. We performed a systematic literature review within PubMed, Google Scholar, and Scopus, with additional use of the snowballing method to find studies including data on serum Cys C concentrations in the first 30 DOL. We identified 15 papers that met criteria, published from 2000 to 2019, from 10 countries across 4 continents, in 1468 babies born preterm. Cys C was superior to creatinine in 11/13 studies, and equal in 2/13. For infants born at 24-28 weeks GA, the DOL1 Cys C concentrations ranged from 1.44 to 1.90 mg/L, from 1.20 to 1.77 on DOL3, and from 1.36 to 2.02 between DOL 4 and 30. For infants born at 29-33 weeks GA, the DOL1 Cys C values ranged from 1.41 to 1.96 mg/L, from 1.28 to 1.70 on DOL3, and 1.51 to 1.87 between DOL 4 and 30. For preterm infants born after 34 weeks GA, the DOL1 Cys C values ranged from 1.22 to 1.96 mg/L, from 1.24 to 1.85 on DOL3, and 1.22 to 1.82 between DOL 4 and 30. This systematic review provides generalizable worldwide reference data on Cys C that could be used to estimate progression or resolution of abnormal kidney function in the first months after preterm birth, stratified by GA.

Creatinine filtration kinetics in critically Ill neonates

BACKGROUND

Creatinine values are unreliable within the first weeks of life; however, creatinine is used most commonly to assess kidney function. Controversy remains surrounding the time required for neonates to clear maternal creatinine.

METHODS

Eligible infants had multiple creatinine lab values and were admitted to the neonatal intensive care unit (NICU). A mathematical model was fit to the lab data to estimate the filtration onset delay, creatinine filtration half-life, and steady-state creatinine concentration for each subject. Infants were grouped by gestational age (GA) [(1) 22-27, (2) >27-32, (3) >32-37, and (4) >37-42 weeks].

RESULTS

A total of 4808 neonates with a mean GA of 34.4 ± 5 weeks and birth weight of 2.34 ± 1.1 kg were enrolled. Median (95% confidence interval) filtration onset delay for Group 1 was 4.3 (3.71, 4.89) days and was significantly different than all other groups (p < 0.001). Creatinine filtration half-life of Groups 1, 2, and 3 were significantly different from each other (p < 0.001). There was no difference in steady-state creatinine concentration among the groups.

CONCLUSIONS

We quantified the observed kidney behavior in a large NICU population as a function of day of life and GA using creatinine lab results. These results can be used to interpret individual creatinine labs for infants to detect those most at risk for acute kidney injury.

IMPACT

One of the largest cohorts of premature infants to describe the evolution of kidney development and function over their entire hospitalization. New concept introduced of the kidney filtration onset delay, the time needed for the kidney to begin clearance of creatinine, and that it can be used as an early indicator of kidney function. The smallest premature infants from 22 to 27 weeks gestation took the longest time to begin and complete maternal creatinine clearance. Clinicians can easily compare the creatinine level of their patient to the normative curves to improve understanding of kidney function at the bedside.

Female preterm indigenous Australian infants have lower renal volumes than males: A predisposing factor for end-stage renal disease?

Aim

Indigenous Australians have an increased risk of developing chronic kidney disease (CKD). Indigenous women have a higher rate of CKD than men. In a cohort of Indigenous and non‐Indigenous preterm neonates, we assessed total renal volume (TRV) (a proxy indicator for nephron number). We hypothesized that there would be no difference in renal volume between these two groups at term corrected (37 weeks gestation).

Methods

Normally grown preterm neonates less than 32 weeks of gestation were recruited and at term corrected dates, the neonates underwent renal ultrasonography (TRV measurements), urine microalbumin‐creatinine ratio and serum analysis for Cystatin C measurement for estimated glomerular filtration rate (eGFR) calculation.

Results

One hundred and five neonates (38 Indigenous; 67 non‐Indigenous) were recruited. Indigenous neonates were significantly more premature and of lower birth weight. At term corrected age, Indigenous neonates had a significantly smaller TRV (18.5 (4.2) vs 21.4 (5.1) cm³; P = 0.027) despite no significant difference in body weight. Despite having a smaller TRV, there was no significant difference in eGFR between Indigenous and Non‐indigenous neonates (47.8 [43.2–50.4] vs 46.2 [42.6–53.3] ml/min per 1.73 m²; P = 0.986). These infants achieve similar eGFR through hyperfiltration, which likely increases their future risk of CKD. There was no difference in microalbumin‐creatinine ratio. Female Indigenous neonates, however, had significantly smaller TRV compared with Indigenous male neonates (15.9 (3.6) vs 20.6 (3.6) cm³; P = 0.006), despite no difference in eGFR, birth weight, gestational age, and weight at term corrected.

Conclusion

The difference in TRV is likely to be an important risk factor for the difference in morbidity and mortality from renal disease reported between male and female Indigenous adults.

Indigenous Australians are known to have an increased risk of developing CKD. The authors examined total renal volume (TRV) in a cohort of Indigenous and non‐Indigenous preterm neonates, and found that female Indigenous neonates had significantly smaller TRV compared with Indigenous male neonates.