Strokes occur in infants and children much more frequently than previously reported, according to a study in Stroke: Journal of the American Heart Association.
Heather J. Fullerton, MD, associate professor of neurology at the University of California, San Francisco, and colleagues found that imaging studies, along with diagnostic codes on medical charts, show the rate of stroke for infants and children is two to four times higher than commonly thought.
"Traditional methods using diagnostic codes work fairly well to identify stroke in studies on adults, but they miss a large proportion of cases when applied to infants and children," said Fullerton.
The authors reported that the undercount occurs because coders aren’t use to applying stroke codes to children and because of typing errors.
Researchers analyzed the records of 2.3 million children enrolled in the Kaiser Permanente managed care plan in Northern California. They used two methods to search for stroke cases—examining diagnostic codes entered on medical charts for billing purposes, and using keywords suggesting a stroke on radiology reports.
They confirmed 205 cases of ischemic stroke—an incidence of 2.4 strokes per 100,000 children a year. This is two to four times higher than previous estimates—based only on examining diagnostic codes—of between 0.54 and 1.2 per 100,000 U.S. children per year.
In a comparison of the search methods used to identify stroke victims, the researchers found that the radiology search was a far more sensitive measure than the diagnostic code search.
“Studies based on ICD-9 [diagnostic] codes may vastly underestimate the incidence and cost of pediatric stroke," said Fullerton, adding that because the study was limited to one healthcare organization, researchers can’t be certain that the limitations of ICD-9 code searches would be the same in other systems.
“Our findings suggest that the field needs more prospective studies,” Fullerton said. “Although more costly, prospective studies can capture more pediatric strokes by identifying them as they occur.”