April 6 (UPI) -- Nearly one in three children and teens who develop a severe COVID-19 complication called MIS-C suffer heart dysfunction or symptoms similar to heart failure, a study published Monday by JAMA Pediatrics found.
MIS-C, or multi-system inflammatory syndrome in children, a rare complication of coronavirus infection, causes symptoms similar to those of heart failure in 31% of patients, while 51% see dangerous drops in blood pressure levels, the data showed.
In addition, nearly one in four pediatric patients with the condition experiences a build-up of excess fluid around the heart and 17% show signs of myocarditis, or inflammation of the heart muscle.
Just under 60% of the children who develop MIS-C as a result of COVID-19 require treatment in a hospital intensive care unit, though less than 2% ultimately die from the condition.
"The long-term effect of these complications is poorly understood, but follow-up studies to better elucidate the long-term outcomes of MIS-C have been initiated," researchers from the U.S. Centers for Disease Control and Prevention wrote.
"In addition to understanding long-term outcomes, these studies may help in understanding the optimal level of follow-up care needed after patients are discharged from hospital or intensive care," they said.
Children and teens age 18 and younger are thought to be at lower risk for COVID-19 infection, serious illness and death than adults, according to the CDC.
Of the nearly 31 million confirmed cases of the disease nationally, based on figures from Johns Hopkins University, roughly 10% of them involve children and teens, who also account for just 2% of virus-related hospitalizations, the CDC estimates.
However, about 1% of young people with COVID-19 develop MIS-C, a condition characterized by severe inflammation in multiple key organs that has been compared to Kawasaki disease, a rare heart condition diagnosed in infants that can shorten life expectancy.
For their analysis, the researchers reviewed the clinical and lab records of more than 1,700 people age 20 and younger diagnosed with MIS-C as a result of COVID-19 between March 2020 and January of this year.
Of those with MIS-C included in the analysis, 71% were Black or Hispanic and 58% were male. About 86% of the young people with MIS-C were age 14 and younger.
The states with the highest prevalence of MIS-C cases related to COVID-19 were Alaska, Arizona, Louisiana, Maryland, Massachusetts, Mississippi, Nevada, New York, Tennessee and Wisconsin, as well as Washington, D.C.
The location and timing of "MIS-C in close association with the COVID-19 pandemic ... are consistent with earlier hypotheses that the emergence of MIS-C is due to delayed immunologic responses to infection," the CDC researchers wrote.
With uncertainty about future spread of COVID-19, they said that "physicians should maintain a high index of suspicion for MIS-C to promptly diagnose and treat these patients."