Hypertension often goes undiagnosed in children

CHICAGO – Pediatric records suggest doctors fail to diagnose high blood pressure in most children and teenagers who have it, an oversight that could have devastating health consequences once they become adults, researchers reported Tuesday.

The study, published in this week’s Journal of the American Medical Association, found that among children whose blood pressure readings indicated hypertension, only one in four had the diagnosis documented in their electronic medical records.

If the findings are extrapolated nationwide, as many as 1.5 million children and teens could have undiagnosed high blood pressure, said Dr. David C. Kaelber, a pediatrician at Boston Children’s Hospital and a study co-author. That compares with about 500,000 children who have been correctly diagnosed.

“I expected to find some under-diagnosis, but it was the magnitude of the under-diagnosis that was most striking,” Kaelber said. He said the study was “a wake-up call for providers as well as parents that we need to become much more educated and careful about looking at blood pressure in children.”

Other research already has suggested that high blood pressure is becoming more common in children and adolescents in the U.S., paralleling the nation’s obesity epidemic. The estimated prevalence is between 2 percent and 5 percent.

Blood pressure refers to the force exerted on artery walls as blood flows through the body. Untreated hypertension usually does not cause life-threatening problems in children because the damaging effects occur over time, but it has been linked to heart attacks, strokes and kidney failure in adults.

Normal blood pressure for adults is a systolic pressure below 120 and a diastolic pressure of 80 as measured in millimeters of mercury. Systolic pressure between 120 and 139 or a diastolic pressure between 80 and 89 means prehypertension, or slightly elevated blood pressure that often leads to full-blown hypertension.

Identifying the condition in children, however, is far more complicated. Guidelines developed by medical experts define hypertension as blood pressure at or higher than the 95th percentile for age, sex and height during three different office visits. Prehypertension is defined as average blood pressure at or higher than the 90th percentile for age, sex and height, or a reading of more than 120 over 80.

That’s where it gets sticky. For example, the 95th blood pressure percentile for a 15-year-old girl in the 75th percentile of height is 129 over 84, but the 95th percentile for an 8-year-old boy in the 10th percentile of height is 112 over 76. Although tables are available to help clinicians determine whether blood pressure is abnormal, they don’t always use them.