IMAGE: GETTY IMAGES/PHOTODISC/ RANA FAURE
In 2007, David Kaelber, MD, PhD, MPH, co-authored a study indicating that pediatricians significantly underdiagnose children with hypertension and prehypertension.1 He noted that one of the major reasons for this was that the blood pressure (BP) tables in the Fourth Report on the Diagnosis, Evaluation, and Treatment of High BP in Children and Adolescents2 were unwieldy, requiring physicians to look up BP values based on a patient's gender, age, and height percentile. The study was named one of the top 10 breakthroughs in cardiovascular and stroke medicine for 2007 by the American Heart Association, and earned a 2008 Health Breakthrough Award from Ladies' Home Journal.
Recently, Kaelber and colleagues created a simplified BP table for screening children for hypertension or prehypertension (TABLE 1 in the print and digital editions).3 The new table reduces the number of BP values from 476 in the Fourth Report to just 64, and has only one threshold value of abnormal systolic and diastolic BP, by gender, for each year of life (ages 3 to 18). These modifications make it easy to identify abnormal BP values in almost any potential care or screening setting.
Q: Pediatricians screen for a wide variety of conditions at well-child visits including hearing, vision, lead exposure, anemia, developmental issues, and obesity, just to name a few. Why should pediatricians also be aware of age-related thresholds for hypertension and prehypertension?
With prevalence rates of up to 5% each, hypertension and prehypertension are common chronic diseases of childhood—as common as many other diseases for which we screen. For example, abnormal lead levels (≥10 ug/dL) occur in less than 3% of children,4 yet risk factor and/or blood lead level screening are recommended for all children. Moreover, hypertension and prehypertension are well-known obesity-related conditions, so with the increase in weight problems in children, the prevalence of BP problems is rising. Finally, secondary hypertension (high BP caused by a secondary disease) is a relatively common cause of hypertension in children. Therefore, by detecting hypertension and evaluating its cause—cardiac, renal, endocrine, or other sources—additional new medical problems may be identified and addressed.
Q: Your simplified table is derived from tables published in the Fourth Report. Pediatricians can find these tables reproduced in the Harriet Lane Handbook. Why is a simplified table needed?
The traditional BP tables are complex because they incorporate a child's age, gender, and height percentile. This simplified table only relies on age and gender. This simplification is important because it reduces the complexity of the BP table, and focuses on easily identifiable information. When an intake person checks BP at a routine office visit, or a BP screening is provided at a school, a whole additional level of time and complexity is needed if in addition to noting the BP, one must also measure the child's height and then plot their height percentile. These additional challenges may discourage providers from offering opportunities for BP screening outside the well-child visit.