By Elaine Gottlieb
First of a two-part series on cardiovascular prevention in children. Read part two.
As childhood obesity has increased over the past 30 years, so has pediatric hypertension, which now affects one in 20 children. However, 48 percent of children with high blood pressure (BP) are of normal weight; other risk factors include low birth weight, which has also increased in the past 30 years (more recently dipping slightly to about 8 percent of births).
While children with hypertension rarely develop diseases that adults do, such as myocardial infarction, heart failure and stroke, they are at risk for adult hypertension and early symptoms of heart disease. “Attacking pediatric hypertension is the next frontier in cardiovascular disease prevention,” says Justin Zachariah, MD, MPH, of the Department of Cardiology at Boston Children’s Hospital.
The Affordable Care Act’s mandate to identify elevated BP in children is expected to increase referrals for screening. But diagnosing pediatric hypertension through BP screening in the clinic can be problematic. In a recent study, Zachariah found that ambulatory BP monitoring (ABPM) with a take-home device is both effective and cost-effective – especially when done from the get-go.
“Many children referred for screening in our hypertension program don’t have hypertension,” Zachariah says. “Doing a full evaluation for a child who isn’t truly hypertensive is time-consuming, anxiety-producing and resource intensive. We evaluate children who don’t need it and overlook children who do. We need to target our attention and resources in a better way.”
Children often become anxious at the doctor’s office, resulting in reactive or “white coat” hypertension. Also, target blood pressure values vary with children’s age, sex and height, making them difficult for clinicians to remember and children’s readings easy to misinterpret. A study of pediatric hypertension conducted at a large academic medical system in northeast Ohio found that out of 14,000 children, only 500 had hypertension. Of that number, only 26 percent were correctly identified by pediatricians.
For that reason, ABPM is emerging as the gold standard for hypertension diagnosis for many pediatric hypertension specialists. Administered at home for a 24-hour period using a blood pressure cuff attached to a cell phone-size recorder, ABPM can identify reactive hypertension and masked hypertension (in which in-clinic BP is normal but ambulatory BP is elevated) and reduce inadequate or inappropriate testing.
Zachariah and colleagues recently conducted a retrospective study comparing the cost and effectiveness of three scenarios for using ABPM, studying 170 patients who were referred to nephrology or cardiology clinics for confirmation of hypertension. The patients’ mean age was 15.
- In Strategy 1, all patients with a clinic BP in the 95th percentile and above have a hypertension work-up in the clinic.
- In Strategy 2, all patients with a clinic BP in the 90th percentile and above undergo ABPM, and those with prehypertension or hypertension on ABPM have a hypertension work-up in the clinic.
- In Strategy 3, all patients referred to the clinic undergo ABPM, and those with prehypertension or hypertension have a hypertension work-up in the clinic.
ABPM hypertension was identified in 55 patients (nearly a third), including 11 with masked hypertension, 12 with ambulatory hypertension and 32 with severe ambulatory hypertension. Strategy 1 identified 40 percent of true hypertensive children (those with hypertension on ABPM); Strategy 2 identified 70 percent; and Strategy 3, 100 percent (by definition, since ABPM was used as the gold standard for this study).
Strategy 3 – universal ABPM – had the highest total costs; Strategy 2, the lowest. But Strategy 3 had a lower average charge per hypertensive child identified than Strategy 2. This may make it the most cost-effective strategy in the long run, as it ensures that only truly hypertensive children will undergo intensive evaluations.
“It may be cost-effective to use ABPM as the initial test for all patients referred to a pediatric center for elevated blood pressure,” says Zachariah. “Since the clinical goal is to streamline management for hypertensive children, we combined the proportion of children correctly identified with the charges per child identified as the key metric of success. This combined outcome prevents the perverse result of saving health care dollars by ignoring children who need help.”
He now hopes to conduct further research on ABPM’s effectiveness in larger groups of patients and its relationship to intermediate- and long-term patient outcomes. “We’d like to know whether evaluating pediatric patients with ABPM and identifying hypertension at a young age could prevent thickening of the heart and strokes,” he says.
Elaine Gottlieb is a freelance medical writer who writes for academic medical centers and health care organizations nationwide.