Hypertension Appears to Be Frequently Undiagnosed in Children and Adolescents

In a study of children and adolescents with hypertension, only about one in four had been previously diagnosed with the condition, according to a study in the August 22/29 issue of JAMA.

Hypertension, with an estimated prevalence of between 2 percent and 5 percent, is a common chronic disease in children and is increasing in prevalence with the pediatric obesity epidemic. Diagnosis of hypertension in children is complicated because normal and abnormal blood pressure values vary with age, sex, and height, according to background information in the article.

Matthew L. Hansen, M.D., of Case Western Reserve University, Cleveland, and colleagues conducted a study to determine the frequency of undiagnosed hypertension and prehypertension in 3- to 18-year-old children. The study included 14,187 children and adolescents who were observed at least three times for well-child care between June 1999 and September 2006 in outpatient clinics.

The researchers found that 507 children (3.6 percent) met the criteria for hypertension. Of the children with hypertension, only 131 (26 percent) had a diagnosis of hypertension or elevated blood pressure documented in the electronic medical record; i.e., 376 of 507 participants (74 percent) had undiagnosed hypertension. Four hundred and eighty five (485) children (3.4 percent) met criteria for prehypertension. Of these children, 55 (11 percent) had a diagnosis of hypertension or elevated blood pressure documented in the electronic medical record.

Patient characteristics significantly associated with having a diagnosis of hypertension included a 1-year increase in age over age 3, number of elevated blood pressure readings beyond three, increase of 1 percent in height-for-age percentile, having an obesity-related diagnosis, and the number of blood pressure readings in the stage 2 hypertension range.  Patient characteristics significantly associated with having a diagnosis of prehypertension included a 1-year increase in age over age 3 and number of elevated blood pressure readings beyond three.

“Identification of elevated blood pressure in children meeting prehypertension or hypertension criteria is important because of the increasing prevalence of pediatric weight problems and because secondary hypertension is more common in children than adults, requiring identification and appropriate work-up. If a patient’s pediatric clinician does not identify abnormal blood pressure, it may be years before the abnormal blood pressure is detected, leading to end-organ damage. Because effective treatments for abnormal blood pressure exist, these long-term sequelae can be avoided with early diagnosis,” the authors write.

“Although this study identifies the problem of undiagnosed hypertension in children, it also points to the potential of electronic medical records to help address this issue. A clinical decision support algorithm built into an electronic medical record that would automatically review current and prior blood pressures, ages, heights, and sex to determine if abnormal blood pressure criteria had been met could remedy the relatively poor identification of abnormal blood pressure. The algorithm could indicate if any abnormal blood pressure … already existed and prompt the pediatric clinician that the child appears to have undiagnosed abnormal blood pressure. In addition, the clinical decision support algorithm could provide guideline-based evaluation, treatment, and parent/patient education materials to the clinician.”

JAMA. 2007; 298(8):874-879.