53 - Incidence and Risk Factors for Acute Kidney Injury in Extremely Low Birth Weight Infants– Experience at a Single Center Level III Neonatal Intensive Care Unit

Poster Number: 53
Publication Number: 53.2139

Background: Neonatal acute kidney injury (AKI) has been previously poorly studied with different definitions used. The incidence of AKI reported varies significantly from 18% - 55% using the modified KDIGO criteria. Recent studies in pediatric and neonatal AKI suggest that survivors of AKI in the neonatal period are at increased risk for chronic kidney disease and warrant long-term follow-up. Studies have shown that neonatal AKI is associated with poor outcomes and certain risk factors such as being born with extremely low birth weight (ELBW) have been established.

Objective: To determine the incidence of AKI in ELBW and identify its risk factors.

Design/Methods: Retrospective study of all ELBW infants admitted to the neonatal intensive care unit at Los Angeles General Medical Center from July 2015 to July 2023. Neonatal and maternal demographics, maternal and neonatal medications, laboratory results, clinical course and survival outcomes were collected. To define AKI, we used the Modified KDIGO criteria. (Table 1) We opted not to use urine output in the staging of AKI due to limitations of data collection. Infants were grouped into absent AKI, and present AKI.

Results: A total of 125 ELBW infants were included in the study. The incidence of AKI was 42% (52/125). Onset of AKI occurred at a median postnatal day of life 12 (IQR 5, 27) and resolved at median day 7 (IQR 4,14). ELBW infants who had AKI were significantly younger, of lower BW, had lower 5 minute Apgar score, higher rate of hypotension requiring vasopressor use and higher rate of exposure to gentamicin and vancomycin. There was no significant difference in gender, 1 minute Apgar score, use of antenatal steroid, exposure to indomethacin and furosemide between the two groups. There was no significant difference in maternal illness and maternal use of non- steroidal anti-inflammatory drugs, angiotensin converting enzyme inhibitors and substance use. (Table 2) 50 infants had data on staging. Majority of infants 36/50 (78%) had Stage 1, 9/50 (18%) had Stage 2 and 5/50 (10%) had Stage 3. There were no significant differences in the GA and BW of infants in the different stages of AKI but Stage 1 had an earlier onset compared to Stage 2 and 3. (Table 3)

Conclusion(s): Our data showed that the incidence of neonatal AKI in ELBW infants is high and likely underreported. Nephrotoxic medications should be judiciously used in lower BW, lower GA and hemodynamically unstable ELBW, and their kidney function should be closely monitored. More investigation as to differences between causes for different stages of AKI in this population and long term outcomes are needed.