Acute Kidney Injury Underrecognized in Hospitalized Children

By Will Boggs MD

August 12, 2020

NEW YORK (Reuters Health) - Acute kidney injury (AKI) in hospitalized children is often underrecognized and commonly not followed up after discharge, according to a study of electronic medical records.

An estimated one in four children admitted to intensive-care units (ICUs) experience AKI, but less is known about pediatric AKI outside of critical-care settings.

Dr. Alan S. Go of Kaiser Permanente Northern California (KPNC), in Oakland, and colleagues used KPNC electronic medical records from 2008 through 2016 to examine trends in the incidence of hospitalized AKI among children across critical- and noncritical-care settings, as well as outpatient follow-up kidney-function monitoring after AKI.

During this period, 7.4% of all pediatric hospitalizations were associated with AKI, representing 0.2% of the overall pediatric patient population, the researchers report in Pediatrics.

Compared with children without AKI, children with AKI were more likely to be older, male and Black and had significantly higher risks of in-hospital death (1.2% vs. 0.0% for children without AKI) and longer hospital length of stay (7.9 vs. 3.8 days).

The population incidence of AKI remained similar over this period, averaging 0.70 cases per 1,000 person-years. But among hospitalized children, the risk of AKI increased significantly from 6.0 cases per 100 hospitalizations in 2008 to 8.8 cases per 100 hospitalizations in 2016.

This increase was largely driven by a significant increase in stage 1 AKI; the combined incidence of severe AKI (stages 2 and 3) hovered around 1.6 cases per 100 hospitalizations per year throughout this period.

Among 3,582 hospitalized AKI episodes, 26.0% were discharged with serum creatinine levels that had returned to baseline and 28.2% with levels that remained elevated compared with baseline; 45.7% had no inpatient serum creatinine measurements after the value used to define AKI.

Follow-up testing rates averaged 15.8% at 30 days after discharge, increasing to 28.5% at 365 days after discharge. Follow-up testing at 30 days was higher among patients with severe, confirmed and unresolved AKI (45.7%) than among those with severe, resolved AKI (33.0%), but more than half of these episodes received no follow-up test.

"To reduce the potentially longer-term consequences of AKI in children, further efforts should be made for the systematic recognition and awareness of AKI in all inpatient settings with appropriate, risk-based postdischarge follow-up kidney function monitoring by pediatricians and other pediatric primary care providers," the authors conclude.

"Studies are also needed to examine the etiologies, long-term clinical outcomes, and more effective preventive and therapeutic strategies for pediatric AKI, especially in non-critically ill children," they add.

Dr. Vikas R. Dharnidharka of Washington University in St. Louis and St. Louis Children's Hospital, in Missouri, who coauthored a linked editorial, told Reuters Health by email, "By day 365, only 28.5% with unresolved AKI had a follow-up serum creatinine measurement, a value that did not increase beyond 71% for confirmed, unresolved stage-3 AKI. These numbers should be a lot higher."

"The evidence that a large number of these patients can go on to chronic kidney disease is now well established," he said. "Many of the patients who develop AKI may then go unrecognized for several years before a diagnosis of chronic kidney disease is made."

Dr. Dharnidharka advised, "At the time of hospital discharge, please schedule follow-up visits with a nephrologist for hospitalized patients who develop stage-2 or -3 acute kidney injury."

Dr. Scott Sutherland of Stanford University, in Palo Alto, California, who has also researched AKI in pediatric patients, told Reuters Health by email, "The definition of AKI is based upon increases in serum creatinine and decrements in urine output. This study, for valid reasons, only used the creatinine criteria. The best data available suggest that using the creatinine but not the urine-output criteria underestimates the incidence of AKI, (so) AKI is likely even more common than this study suggests."

"This study demonstrates that AKI is quite common outside of ICUs and that a significant proportion of this non-ICU AKI is severe," he said. "I think this is particularly relevant to pediatric, family medicine, and internal medicine providers who care for hospitalized children - we all should be considering AKI risk in our hospitalized patients."

"The Kidney Disease: Improving Global Outcomes (KDIGO) AKI guidelines suggest follow-up monitoring in patients who experience AKI; however, this study really underscores the fact that this is not happening with regularity," Dr. Sutherland said. "Children who experience AKI, especially those with more severe disease, should receive follow-up care that is consistent with the prevailing best practice."

He added, "One aspect of AKI epidemiology that remains understudied is community-acquired AKI. There is very little data; however, that which exists suggests that AKI is not an uncommon occurrence in non-hospitalized children. Thus, even providers who only provide ambulatory care need to be aware of AKI and the risk factors which predispose to developing it."

Dr. Go did not respond to a request for comments.

SOURCE: and Pediatrics, online August 11, 2020.