Article of the Month - Oct 2020

Under-Recognition of Neonatal Acute Kidney Injury and Lack of Follow-Up

American Journal of Perinatology, September 2020. doi: 10.1055/s-0040-1716841

Jean-Philippe Roy, MD, Stuart L. Goldstein, MD, Meredith P. Schuh, MD

Reviewed by Saritha Ranabothu

Background:

Acute kidney injury (AKI) occurs in 30% of all infants in the neonatal intensive care unit (NICU). Some of the risk factors include prematurity, low birth weight. Long-term outcome studies of premature and low birth weight patients showed renal dysfunction or other complications like hypertension, proteinuria several years after AKI. However less is known about the long-term follow-up of all infants with AKI in the neonatal period, regardless of birth weight or gestational age.

What was the purpose of the study?

To assess follow-up after discharge and early signs of CKD in NICU graduates with AKI. They also assessed under recognition of AKI  just based on serum creatinine alone.

What was the study design (randomized control trial, retrospective cohort study, single center, multi-center, etc.)?

A retrospective chart review of the Cincinnati Children’s Hospital Medical Center cohort of neonates (n=81) included in the AWAKEN trial, 77 of the patients had sufficient data to review from 6 months of age to 5 years

What were the characteristics of the sample (pre-term, term, specific underlying disease or general NICU population, weight, etc.)?

All the neonates admitted to NICU were included except those that were >14 days of age at time of admission, congenital heart disease requiring surgical repair within 7 days of life, lethal chromosomal anomaly, death within 48 hours of NICU admission, and severe/bilateral congenital kidney and urinary tract abnormalities.

AKI was defined based on neonatal modified KDIGO criteria.

Early signs of CKD were defined as hyperfiltration (eGFR >150 ml/min/1.73 m2), proteinuria, abnormal renal imaging (lack of growth/scarring), hypertension (if on antihypertensive medications)

What are the results/main learning points?

47 out of 77 patients had AKI. 45 diagnosed based on urine out put and 5 based on serum creatinine. 3/47 of them (2 with stage 2 AKI and one with stage 3 AKI) had nephrology consult during admission and only 2 of them had AKI diagnosis on discharge documentation and nephrology follow up. 22 patients (10 with AKI and 12 with no AKI) had at least one component of early signs of CKD.  Only 14/22 had at least one creatinine. 3/7 (43%) in AKI group had hyperfiltration (eGFR >150 mL/min/ 1.73 m2) and none in no AKI group. No other early signs of CKD were noted during study period.  This study shows under recognition as well under reporting of AKI in high risk population leading to lack of short and long-term follow up.

What are the implications?

Serum creatinine is insufficient to diagnose AKI in high-risk neonates. While this study is not able to prove statistically significant rates of hyperfiltration or other CKD markers due to lack of follow-up data after AKI. This study supports that we must improve our diagnosis, documentation, and infrastructure for follow up of neonates with AKI.

Limitations:

Potential misclassification of UOP-AKI, no multivariate analysis to account for confounding factors (prematurity, LBW) due to sample size. One of the notable limitations from this study and AWAKEN was the need to assess UOP based on diaper weights.