High Blood Pressure In Children Frequently Undiagnosed

02/24/11  Portland, Ore.

A study by an Oregon Health & Science University resident has found that only about one in four children with hypertension is diagnosed with the condition.

The study is published in the current issue of The Journal of the American Medical Association  (JAMA).

Between 2 percent and 5 percent of children have hypertension, with rates increasing due to the prevalence of childhood obesity. Unlike blood pressure readings in adults, readings in children vary according to age, sex and height. Hypertension in children is diagnosed based on three elevated blood pressure readings during three different physician visits. These varying factors make it difficult for physicians to diagnose.

Matthew Hansen, M.D.,an OHSU resident in emergency medicine, conducted the study with colleagues while he was a medical student at Case Western Reserve University in Cleveland. They reviewed the electronic medical records of more than 14,000 children ages 3 to 18 who were seen by a pediatrician at least three times for well-child visits between June 1999 and September 2006.

The researchers found that the criteria for hypertension were met by 507 children (3.6 percent). Of the children with hypertension, only 131 (26 percent) had a diagnosis of hypertension or elevated blood pressure documented in the electronic medical record. This means 74 percent of the children who met the criteria for hypertension had no diagnosis.

“The results really weren’t that surprising,” said Hansen, lead author of the paper. “We assumed that the complexity of the normal blood pressure ranges in children prevents most pediatric clinicians from paying close attention to blood pressure.”

Secondary hypertension, high blood pressure related to another disease process, is more common in children than in adults. This requires proper identification so the disease itself can be treated. If abnormal blood pressure is not identified by a patient’s pediatric clinician, it may be years before the abnormal blood pressure is detected, leading to end-organ damage. Hypertension in childhood has also been shown to be an independent risk factor for hypertension in adulthood and is associated with early markers of cardiovascular disease.

The researchers found older and taller children were more likely to have a hypertension diagnosis, probably because their normal blood pressure range was similar to that for adults, which is well known to be 120/80 mm Hg. Children with an obesity-related diagnosis and children who had an increased number of elevated blood pressure readings also were more likely to have a hypertension diagnosis.

Hansen believes this study shows the potential of electronic medical records, which have become more prevalent in hospitals in recent years.

“We were able to conduct this study with no funding,” said Hansen. “A group of us conducted this study over the course of a year in our spare time. Before the introduction of electronic medical records, it would have taken several years and hundreds of thousands of dollars to have found these results using actual patients.”

Hansen also believes electronic medical records could be the answer to helping physicians better diagnose childhood hypertension. A system could be built into the electronic medical record to automatically review current and prior blood pressure readings, age, height and sex of patient to prompt the physician if high blood pressure criteria had been met.