Low albumin levels are independently associated with neonatal acute kidney injury: a report from AWAKEN Study Group

BACKGROUND

Data from adult and pediatric literature have shown an association between albumin levels and AKI. Whether hypoalbuminemia and neonatal AKI are associated has not been studied.

METHODS

We evaluated the association of albumin with early (during the first postnatal week) and late (after the first postnatal week) AKI for 531 neonates from the Assessment of Worldwide AKI Epidemiology in Neonates (AWAKEN) database and for 3 gestational age (GA) subgroups: < 29, 29 to < 36, and ≥ 36 weeks GA.

RESULTS

Low albumin levels were associated with increased odds of neonatal AKI; for every 0.1 g/dL decrease in albumin, the odds of late AKI increased by 12% on continuous analysis. After adjustment for potential confounders, neonates with albumin values in the lowest quartiles (< 2.2 g/dL) had an increased odds of early [Adjusted Odd Ratio (AdjOR) 2.5, 95% CI = 1.1-5.3, p < 0.03] and late AKI [AdjOR 13.4, 95% CI = 3.6-49.9, p < 0.0001] compared to those with albumin in the highest quartile (> 3.1 g/dL). This held true for albumin levels 2.3 to 2.6 g/dL for early [AdjOR 2.5, 95% CI = 1.2-5.5, p < 0.02] and late AKI [AdjOR 6.4, 95% CI = 1.9-21.6, p < 0.01]. Albumin quartiles of (2.7 to 3.0 g/dL) were associated with increased odds of late AKI. Albumin levels of 2.6 g/dL and 2.4 g/dL best predicted early (AUC = 0.59) and late AKI (AUC = 0.64), respectively. Analysis of albumin association with AKI by GA is described.

CONCLUSIONS

Low albumin levels are independently associated with early and late neonatal AKI. Albumin could be a potential modifiable risk factor for neonatal AKI.

Acute Kidney Injury and Bronchopulmonary Dysplasia in Premature Neonates Born Less than 32 Weeks' Gestation

OBJECTIVE

This study aimed to evaluate the association between acute kidney injury (AKI) and bronchopulmonary dysplasia (BPD) in infants born <32 weeks of gestational age (GA).

STUDY DESIGN

Present study is a secondary analysis of premature infants born at <32 weeks of GA in the Assessment of Worldwide Acute Kidney Injury Epidemiology in Neonates (AWAKEN) retrospective cohort (n = 546). We stratified by gestational age and used logistic regression to determine association between AKI and moderate or severe BPD/mortality.

RESULTS

Moderate or severe BPD occurred in 214 of 546 (39%) infants, while death occurred in 32 of 546 (6%); the composite of moderate or severe BPD/death occurred in 246 of 546 (45%). For infants born ≤29 weeks of gestation, the adjusted odds ratio (OR) of AKI and the primary outcome was 1.15 (95% confidence interval [CI] = 0.47-2.86; p = 0.76). Infants born between 29 and 32 weeks of gestation with AKI had four-fold higher odds of moderate or severe BPD/death that remained after controlling for multiple factors (adjusted OR = 4.21, 95% CI: 2.07-8.61; p < 0.001).

CONCLUSION

Neonates born between 29 and 32 weeks who develop AKI had a higher likelihood of moderate or severe BPD/death than those without AKI. Further studies are needed to validate our findings and evaluate mechanisms of multiorgan injury.

Acute Kidney Injury is Associated with Poor Lung Outcomes in Infants Born ≥32 Weeks of Gestational Age

OBJECTIVE

This study aimed to evaluate the association between acute kidney injury (AKI) and lung outcomes in infants born ≥32 weeks of gestational age (GA).

STUDY DESIGN

Secondary analysis of infants ≥32 weeks of GA in the assessment of worldwide acute kidney injury epidemiology in neonates (AWAKEN) retrospective cohort (n = 1,348). We used logistic regression to assess association between AKI and a composite outcome of chronic lung disease (CLD) or death at 28 days of age and linear regression to evaluate association between AKI and duration of respiratory support.

RESULTS

CLD occurred in 82/1,348 (6.1%) infants, while death occurred in 22/1,348 (1.6%); the composite of CLD/death occurred in 104/1,348 (7.7%). Infants with AKI had an almost five-fold increased odds of CLD/death, which remained after controlling for GA, maternal polyhydramnios, multiple gestations, 5-minute Apgar's score, intubation, and hypoxic-ischemic encephalopathy (adjusted odds ratio [OR] = 4.9, 95% confidence interval [CI]: 3.2-7.4; p < 0.0001). Infants with AKI required longer duration of respiratory support (count ratio = 1.59, 95% CI: 1.14-2.23, p = 0.003) and oxygen (count ratio = 1.43, 95% CI: 1.22-1.68, p < 0.0001) compared with those without AKI.

CONCLUSION

AKI is associated with CLD/death and longer duration of respiratory support in infants born at ≥32 weeks of GA. Further prospective studies are needed to elucidate the pathophysiologic relationship.

Incidence and Risk Factors of Early Onset Neonatal AKI

BACKGROUND AND OBJECTIVES

Neonatal AKI is associated with poor short- and long-term outcomes. The objective of this study was to describe the risk factors and outcomes of neonatal AKI in the first postnatal week.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The international retrospective observational cohort study, Assessment of Worldwide AKI Epidemiology in Neonates (AWAKEN), included neonates admitted to a neonatal intensive care unit who received at least 48 hours of intravenous fluids. Early AKI was defined by an increase in serum creatinine >0.3 mg/dl or urine output <1 ml/kg per hour on postnatal days 2-7, the neonatal modification of Kidney Disease: Improving Global Outcomes criteria. We assessed risk factors for AKI and associations of AKI with death and duration of hospitalization.

RESULTS

Twenty-one percent (449 of 2110) experienced early AKI. Early AKI was associated with higher risk of death (adjusted odds ratio, 2.8; 95% confidence interval, 1.7 to 4.7) and longer duration of hospitalization (parameter estimate: 7.3 days 95% confidence interval, 4.7 to 10.0), adjusting for neonatal and maternal factors along with medication exposures. Factors associated with a higher risk of AKI included: outborn delivery; resuscitation with epinephrine; admission diagnosis of hyperbilirubinemia, inborn errors of metabolism, or surgical need; frequent kidney function surveillance; and admission to a children's hospital. Those factors that were associated with a lower risk included multiple gestations, cesarean section, and exposures to antimicrobials, methylxanthines, diuretics, and vasopressors. Risk factors varied by gestational age strata.

CONCLUSIONS

AKI in the first postnatal week is common and associated with death and longer duration of hospitalization. The AWAKEN study demonstrates a number of specific risk factors that should serve as "red flags" for clinicians at the initiation of the neonatal intensive care unit course.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

Assessment of Worldwide AKI Epidemiology in Neonates (AWAKEN), NCT02443389.

Optimizing the AKI definition during first postnatal week using Assessment of Worldwide Acute Kidney Injury Epidemiology in Neonates (AWAKEN) cohort

BACKGROUND

Neonates with serum creatinine (SCr) rise ≥0.3 mg/dL and/or ≥50% SCr rise are more likely to die, even when controlling for confounders. These thresholds have not been tested in newborns. We hypothesized that different gestational age (GA) groups require different SCr thresholds.

METHODS

Neonates in Assessment of Worldwide Acute Kidney Epidemiology in Neonates (AWAKEN) with ≥1 SCr on postnatal days 1-2 and ≥1 SCr on postnatal days 3-8 were assessed. We compared the mortality predictability of SCr absolute (≥0.3 mg/dL) vs percent (≥50%) rise. Next, we determine usefulness of combining absolute with percent rise. Finally, we determined the optimal absolute, percent, and maximum SCr thresholds that provide the highest mortality area under curve (AUC) and specificity for different GA groups.

RESULTS

The ≥0.3 mg/dL rise outperformed ≥50% SCr rise. Addition of percent rise did not improve mortality predictability. The optimal SCr thresholds to predict AUC and specificity were ≥0.3 and ≥0.6 mg/dL for ≤29 weeks GA, and ≥0.1 and ≥0.3 mg/dL for >29 week GA. The maximum SCr value provides great specificity.

CONCLUSION

Unique SCr rise cutoffs for different GA improves outcome prediction. Percent SCr rise does not add value to the neonatal AKI definition.

Late onset neonatal acute kidney injury: results from the AWAKEN Study

BACKGROUND

Most studies of neonatal acute kidney injury (AKI) have focused on the first week following birth. Here, we determined the outcomes and risk factors for late AKI (>7d).

METHODS

The international AWAKEN study examined AKI in neonates admitted to an intensive care unit. Late AKI was defined as occurring >7 days after birth according to the KDIGO criteria. Models were constructed to assess the association between late AKI and death or length of stay. Unadjusted and adjusted odds for late AKI were calculated for each perinatal factor.

RESULTS

Late AKI occurred in 202/2152 (9%) of enrolled neonates. After adjustment, infants with late AKI had higher odds of death (aOR:2.1, p = 0.02) and longer length of stay (parameter estimate: 21.9, p < 0.001). Risk factors included intubation, oligo- and polyhydramnios, mild-moderate renal anomalies, admission diagnoses of congenital heart disease, necrotizing enterocolitis, surgical need, exposure to diuretics, vasopressors, and NSAIDs, discharge diagnoses of patent ductus arteriosus, necrotizing enterocolitis, sepsis, and urinary tract infection.

CONCLUSIONS

Late AKI is common, independently associated with poor short-term outcomes and associated with unique risk factors. These should guide the development of protocols to screen for AKI and research to improve prevention strategies to mitigate the consequences of late AKI.

Incidence and Risk Factors of Early Onset Neonatal AKI

BACKGROUND AND OBJECTIVES

Neonatal AKI is associated with poor short- and long-term outcomes. The objective of this study was to describe the risk factors and outcomes of neonatal AKI in the first postnatal week.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The international retrospective observational cohort study, Assessment of Worldwide AKI Epidemiology in Neonates (AWAKEN), included neonates admitted to a neonatal intensive care unit who received at least 48 hours of intravenous fluids. Early AKI was defined by an increase in serum creatinine >0.3 mg/dl or urine output <1 ml/kg per hour on postnatal days 2-7, the neonatal modification of Kidney Disease: Improving Global Outcomes criteria. We assessed risk factors for AKI and associations of AKI with death and duration of hospitalization.

RESULTS

Twenty-one percent (449 of 2110) experienced early AKI. Early AKI was associated with higher risk of death (adjusted odds ratio, 2.8; 95% confidence interval, 1.7 to 4.7) and longer duration of hospitalization (parameter estimate: 7.3 days 95% confidence interval, 4.7 to 10.0), adjusting for neonatal and maternal factors along with medication exposures. Factors associated with a higher risk of AKI included: outborn delivery; resuscitation with epinephrine; admission diagnosis of hyperbilirubinemia, inborn errors of metabolism, or surgical need; frequent kidney function surveillance; and admission to a children's hospital. Those factors that were associated with a lower risk included multiple gestations, cesarean section, and exposures to antimicrobials, methylxanthines, diuretics, and vasopressors. Risk factors varied by gestational age strata.

CONCLUSIONS

AKI in the first postnatal week is common and associated with death and longer duration of hospitalization. The AWAKEN study demonstrates a number of specific risk factors that should serve as "red flags" for clinicians at the initiation of the neonatal intensive care unit course.

The Association of Intraventricular Hemorrhage and Acute Kidney Injury in Premature Infants from the Assessment of the Worldwide Acute Kidney Injury Epidemiology in Neonates (AWAKEN) Study

BACKGROUND

Acute kidney injury (AKI) and intraventricular hemorrhage (IVH) are common in premature infants. We previously demonstrated that infants with AKI have a higher hazards ratio to develop grade ≥2 IVH when controlling for confounders. However, that single-center study was unable to show an overall association.

OBJECTIVES

To test the hypothesis that infants diagnosed with AKI have an increased risk of IVH independent of variables associated with both AKI and IVH, we performed a study on 825 infants from the Assessment of Worldwide Acute Kidney Injury Epidemiology in Neonates (AWAKEN) study (a 24-center multinational retrospective cohort).

METHOD

A neonatal modified KDIGO definition of AKI was used based on serum creatinine (SCr) and/or urine output criteria. Baseline SCr was defined as the lowest previous value. IVH was diagnosed with head ultrasounds.

RESULTS

AKI was documented in 22.2% (183/825) of infants and IVH in 14.3% (118/825). Infants with AKI (n = 183) were more likely to have IVH (26.8%, 49/183) than those without AKI (n= 642) who had IVH (10.7%, 69/642, p < 0.0001). After controlling for 5-min Apgar score, vasopressor support within the first week of age, and gestational age, infants with AKI had 1.6 times higher adjusted odds to develop any grade IVH (95% CI 1.04-2.56). Furthermore, infants of gestational age of 22-28 weeks had 1.9 times higher adjusted odds to develop IVH (OR 1.87, 95% CI 1.08-3.23).

CONCLUSIONS

We present the first multicenter evaluation of the association between AKI and IVH in premature infants showing a significant independent association between AKI and IVH. Development of strategies to reduce AKI may also reduce IVH.

Acute kidney injury in neonatal encephalopathy: an evaluation of the AWAKEN database

BACKGROUND

Acute kidney injury (AKI) is common in neonatal encephalopathy (NE) and is associated with worse outcomes. Our objectives were to determine the incidence, risk factors, and outcomes of AKI in infants with NE.

METHODS

We performed a retrospective analysis of infants ≥ 34 weeks' gestational age with a diagnosis of NE from the Analysis of Worldwide Acute Kidney injury Epidemiology in Neonates (AWAKEN) database. AKI was defined using the modified Kidney Disease Improving Global Outcomes criteria. Perinatal and postnatal factors were evaluated. Multivariate logistic and linear regressions were performed.

RESULTS

One hundred and thirteen patients with NE were included. 41.6% (47) developed AKI. Being born outside the admitting institution (OR 4.3; 95% CI 1.2-14.8; p = 0.02), intrauterine growth restriction (OR 10.3, 95% CI 1.1-100.5; p = 0.04), and meconium at delivery (OR 2.8, 95% CI 1.04-7.7; p = 0.04) conferred increased odds of AKI. After controlling for confounders, infants with AKI stayed in the hospital an average of 8.5 days longer than infants without AKI (95% CI 0.79-16.2 days; p = 0.03).

CONCLUSIONS

In this multi-national analysis, several important perinatal factors were associated with AKI and infants with both NE and AKI had longer length of stay than NE alone. Future research aimed at early AKI detection, renoprotective management strategies, and understanding the long-term renal consequences is warranted in this high-risk group of patients.