The revised guidelines of American Academy of Pediatrics, which replaced those developed in 2004 by the National Institute of Health's National Heart, Lung, and Blood Institute, include new normative BP tables that lower abnormal BP cutoffs for most age groups by several mm Hg

According to the 2004 guidelines, the estimated weighted population prevalence of elevated BP among 15,647 healthy, low-risk children aged 5 to 18 years in the study population was 11.8% (95% confidence interval, 11.1%-13.0%). With the 2017 reclassification, 14.2% (95% confidence interval, 13.4%-15.0%) of this population had BPs considered to be abnormal, the authors write.

Further, 470 children previously classified as prehypertensive were reclassified as having stage 1 hypertension, and 54 who had been deemed stage 1 hypertensive were reclassified as stage 2, the authors report.

Of the full cohort, 13,207 children (84.8%) had BPs in the normal range based on both classification systems. When the researchers compared this group with those who were reclassified under the new system in a sex-, age-, and height-matched analysis, they found that those in the reclassified group were significantly more likely to be overweight or obese based on a body mass index z score higher than 1 (55.9% vs 35.0%), and obese based on a body mass index z score higher than 2 (23.5% vs 11.6%).

Differences in lipid profiles were also observed. According to established clinical cutpoints, the children and adolescents who were reclassified upward were more likely to have elevated concentrations of total cholesterol (12.4% vs 9.3%; P = .06), low-density lipoprotein cholesterol (12.2% vs 3.9%; P = .002), triglycerides (22.6% vs 10.7%; P < .001), and hemoglobin A1c (3.4% vs 0.6%; P = .02).

To determine the prevalence of concurrent cardiac risk factors, the researchers conducted a comparative analysis of patients for whom complete data on all of these measures were available (126 in the case group and 140 in the control group) and determined that 67.5% of cases with complete data had risk factors above and beyond elevated BP and 19.0% had more than 2 additional risk factors, compared with 35% and 3.6%, respectively, among the control group.

The additional disease burden associated with the upward classification is not trivial, they emphasize. "For those with elevated BP, lifestyle modifications are recommended (healthy diet, sleep, and physical activity), and the BP is to be reassessed after six months instead of 1 year as in children with normal BP. Similarly, asymptomatic children with stage 1 levels should be reassessed in 1 to 2 weeks, and those with stage 2 levels require more urgent evaluation or referral to a subspecialist within the week."

The study has certain limitations that prevent truly accurate estimation of the prevalence of hypertension in children, cautions Stephen R. Daniels, MD, PhD, from the Department of Pediatrics, University of Colorado School of Medicine, Aurora, in an accompanying editorial.

"While we wait for additional studies, clinicians should use the new American Academy of Pediatrics Clinical Practice Guidelines in their practice," Daniels states. "There are many elements that make the new guidelines easier to use than the old ones. Also, use in practice will provide important clinical data that can ultimately contribute to improvements in our clinical approach to pediatric hypertension."