Retrospective Study Links COVID in Kids With Post-Acute Kidney Outcomes

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Findings underscore importance of long-term monitoring for some children and adolescents

by
Jennifer Henderson, Enterprise & Investigative Writer, MedPage Today
April 11, 2025

COVID-19 infection in children and adolescents was tied to a higher risk of adverse post-acute kidney outcomes, especially among those with preexisting chronic kidney disease (CKD) or acute kidney injury (AKI), retrospective data suggested.

Among nearly 2 million individuals younger than 21 years of age, COVID infection was associated with a higher risk of new-onset stage 2 (mild) or higher CKD; (HR 1.17, 95% CI 1.12-1.22) and stage 3 (moderate) or higher CKD (HR 1.35, 95% CI 1.13-1.62) 28 days to 2 years after the acute phase of infection, reported Yong Chen, PhD, of the University of Pennsylvania in Philadelphia, and colleagues.

SARS-CoV-2 infection also was associated with an increased risk of composite kidney events for kids and adolescents with preexisting CKD (HR 1.15, 95% CI 1.04-1.27) 28 to 179 days after the acute phase of infection and for those with AKI (HR 1.29, 95% CI 1.21-1.38) 90 to 179 days after the acute phase, they said in JAMA Network Open.

The study “represents, to our knowledge, one of the most comprehensive investigations into the long-term kidney outcomes of SARS-CoV-2 infection in pediatric populations,” Chen and colleagues wrote.

“Results of this study suggest that SARS-CoV-2 infection is associated with an increased risk of adverse kidney outcomes, including new-onset CKD and worsening kidney function, particularly among children with preexisting CKD or acute-phase AKI, underscoring the importance of long-term monitoring for kidney health in children and adolescents affected by COVID-19.”

A previous study using national health databases from the U.S. Department of Veteran Affairs found that, after the first 30 days post-infection, veterans who had COVID had increased risks of several adverse kidney outcomes, Chen and colleagues noted. However, studies focused on kids and adolescents have been limited by short duration of follow-up, small sample size, and narrow selection of outcomes, they observed.

Among kids and adolescents with preexisting CKD, Chen and colleagues found that there was an increased risk for an estimated glomerular filtration rate (eGFR) decline of at least 30% both 28 to 179 days after the acute phase of infection (earlier post-acute phase) and 180 to 729 days after the acute phase (later post-acute phase):

• Earlier post-acute phase: HR 1.14, 95% CI 1.03-1.25
• Later post-acute phase: HR of 1.13, 95% CI 1.05-1.20

Among pediatric patients with AKI, there was also an increased risk for eGFR decline at both time periods:

• At least 50% decline in eGFR in the earlier post-acute phase (HR 1.47, 95% CI 1.06-2.03) and the later post-acute phase (HR 1.42, 95% CI 1.31-1.55)
• At least 40% decline in eGFR in the earlier post-acute phase (HR 1.24, 95% CI 1.10-1.41) and the later post-acute phase (HR 1.41, 95% CI 1.21-1.63)
• At least 30% decline in eGFR in the earlier post-acute phase (HR of 1.27, 95% CI 1.20-1.36) and the later post-acute phase (HR of 1.31, 95% CI 1.20-1.43)

While Chen and colleagues said the mechanisms behind the associations are unclear, possible explanations include a direct effect of COVID-19 on the kidneys, the impact of chronic inflammation caused by COVID-19 infection on hemodynamic stability, the therapeutic interventions used to manage severe COVID-19, and economic and social conditions resulting from the pandemic.

“Further investigations are warranted to elucidate the intricate pathways through which these factors interplay, contributing to the observed associations in our study,” they concluded.

Chen and colleagues used data from 19 health institutions in the NIH Researching COVID to Enhance Recovery (RECOVER) initiative from March 1, 2020, to May 1, 2023. Follow-up of 2 years was completed Dec. 1, 2024.

The data included 487,378 kids and adolescents with COVID infection and 1,412,768 without infection. About half were male, and the mean age was 8.2 years.

Misclassification might have existed for both CKD and AKI outcomes, Chen and colleagues acknowledged.

It was difficult to determine whether an increased risk associated with COVID infection in kids and adolescents with preexisting CKD was inherently due to COVID-19 infection itself or whether it reflected a more general risk that these patients may see a negative impact on eGFR when they become ill, they noted.

Future studies could use “dynamic exposure designs, such as matching exposed cases with initially uninfected individuals who may later contract COVID-19,” and “evaluate the cumulative impact of recurrent infections on kidney function,” the researchers suggested.