New Reference Ranges: How Many Kids Really Have High Blood Pressure?

New pediatric blood pressure (BP) clinical practice guidelines were released in 2017 by the American Academy of Pediatrics (AAP).^[1] The new guidelines aimed to establish better reference BP ranges for normal-weight children and adolescents by excluding children who were overweight or obese. The new guidelines also changed some of the terminology and definitions of “normal” and “elevated” BP used in the earlier guidelines (Table). The term “prehypertension” is no longer used.

Table. American Academy of Pediatrics Blood Pressure Definitions

	AGE 1-13 YEARS	AGE ≥13 YEARS
Normal blood pressure	Systolic and diastolic < 90th percentile	< 120/< 80 mm Hg
Elevated blood pressure	≥ 90th to < 95th percentile or 120/80 mm Hg to < 95th percentile	120/< 80 mm Hg to 129/< 80 mm Hg
Stage 1 hypertension	≥ 95th percentile to < 95th percentile + 12 mm Hg or 130/80 mm Hg to 139/89 mm Hg(whichever is lower)	130/80 mm Hg to 139/89 mm Hg
Stage 2 hypertension	≥ 95 percentile + 12 mm Hg or ≥ 140/90 mm Hg (whichever is lower)	≥ 140/90 mm Hg

How Many Kids Are Reclassified?

Using data from the National Health and Nutrition Examination Survey (NHANES) collected from 1999 through 2014, a recent study^[2] aimed to find out how these new reference values might change the proportion of children diagnosed with hypertension. The data included more than 15,000 children (with representative sampling of minority populations) with a median age of 13.4 years. Using NHANES criteria, 35.9% of the sample children were overweight, with 10.3% defined as obese.

Using the updated AAP definitions, 5.8% of the cohort would have been classified “upward,” in terms of BP classification. About one third of those children were reclassified from “normal” BP to either elevated BP or stage 1 hypertension. Approximately one half of that group had “prehypertension” under the old designation but were now classified as having stage 1 hypertension. Only about 5% of those classified upward moved from stage 1 to stage 2 hypertension.

The reclassified children were more likely to have elevated body mass index, lipid abnormalities, or abnormal A1c levels, representing a high-risk population who may require more thorough evaluation for cardiovascular risk.

The population estimate of elevated blood pressure or hypertension increased from 11.8% to 14.2% with the new blood pressure reference values.

Viewpoint

The fact that 14% of the US child and adolescent population would be classified as having elevated BP or hypertension is an amazing statistic and should cause us to all consider how accurately we measure, assess, and treat abnormal BP in children. There are a couple of cautionary notes. First, the NHANES data collected only a single BP measurement, although presumably it was done in a proper manner. The guidelines suggest measuring BP two or three times in the clinic, especially after having the child sit quietly for 5 minutes. Subsequent BPs after the initial measurement in a clinical setting are often lower, and the average BP should be used.

Even if the 14% figure is an overestimate because the children were classified on the basis of a single BP measurement, the true proportion of children with elevated BPs could still be somewhere around 10%—a high figure.

A full review of the guidelines is beyond the scope of this report, but practitioners should avail themselves of the recommended sequence for lifestyle modification, follow-up intervals, indications for beginning medication, and when to initiate more intense management of hypertension.^[1]

https://wb.md/2kE4RaZ