TUESDAY, Aug. 21, 2007 (HealthDay News) -- Doctors spotted only one in four children who had high blood pressure in a new study, showing how easily and often the dangerous problem is missed.
"Hypertension in children is very underdiagnosed," said study co-author Dr. David Kaelber, a pediatrician, internist and fellow at the Center for Information Technology Leadership at Harvard Medical School.
In a group of more than 14,000 youngsters under the age of 18, researchers from Case Western Reserve University in Cleveland and Harvard found that just 26 percent of those with high blood pressure were properly diagnosed.
That means that about 1.5 million American children currently have undiagnosed high blood pressure, Kaelber said.
One of the biggest reasons that hypertension is missed in children is that normal blood pressure values change based on a child's age, gender and height. So, while 120/80 mm/Hg is a normal reading for an adult and for some older children, that same reading could indicate high blood pressure in a younger, shorter child.
Tables are available that allow health-care professionals to plot out a child's height, weight, gender and blood pressure readings. Those tables help determine what percentile a child falls into; youngsters who consistently rank above the 95th percentile are considered to have high blood pressure.
A child must have three readings that fall into the high blood pressure category before the diagnosis can be accurately made, Kaelber said. That makes diagnosis tough, he added, since a long time can elapse between each well-child visit.
Because of these challenges, and because other researchers have noted obesity-linked increases in childhood hypertension, Kaelber's team assessed how well high blood pressure was diagnosed in youngsters.
To do so, they examined data from a group of more than 14,000 children, aged 3 to 18, from northeastern Ohio. Each child had at least three well-child visits during the seven-year study period.
The team found that of the 507 children who had hypertension in that group, just 26 percent had been diagnosed with the disorder. Factors making it more likely a child would be diagnosed with hypertension were older age, taller height, obesity and having more than three abnormal blood pressure readings.
"Those more at risk of having hypertension undiagnosed were children who were younger, shorter and those who didn't have an obesity-related diagnosis," said Kaelber.
Results of the study appear in the Aug. 22/29 issue of the Journal of the American Medical Association.
The good news from this study, explained Kaelber, is that the problem is relatively easy to fix by using electronic medical records. If doctors had a simple software program that could calculate blood pressure based on a child's age, gender and height, and then flag abnormal readings, fewer children would go undiagnosed.
"This study illustrates that there's so much information in health care that's difficult for one person to process, but in a computerized world you don't have to depend on one person," he said.
Dr. Rick Kaskel, chief of pediatric nephrology at The Children's Hospital at Montefiore in New York City, agreed.
"If you had a system where you could put in the age, gender and height, and the system would automatically give you the upper and lower limits for that child, you could see immediately if they're above or below normal," said Kaskel.
Right now, however, he said it's important for parents to realize that high blood pressure can and does occur in children. And, as in adults, hypertension can usually be prevented by making healthy diet and exercise choices, and maintaining a normal weight.
To learn more about high blood pressure in children, visit the Nemours Foundation.