Screening Adolescents for Hypertension

William T. Basco, Jr., MD, FAAP


September 20, 2007

Prevalence of Hypertension and Pre-Hypertension Among Adolescents

McNiece KL, Poffenbarger TS, Turner JL, Franco KD, Sorof JM, Portman RJ
J Pediatr. 2007;150:640-644, 644.e1

The study authors noted that the 2004 guidelines for the diagnosis and classification of hypertension in children increased awareness of the need to screen for elevated blood pressure (BP) at any pediatric visit after age 3 years, and provided guidelines for staging hypertension and how to intervene depending on the staging.[1]

The concept of "prehypertension" was also defined in that report. This study applied the new guidelines to a population of children attending 9 Houston, Texas, schools in 2003-2005. The study authors wanted to quantitate the proportion of children in a community sample who would be classified as prehypertensive and as hypertensive by the new guidelines.

The investigators collected anthropomorphic data on the subjects as well as serial BP measurements (usually 3 different occasions). All readings were taken with automated BP machines, but the initial reading on each subject was disregarded because automated machines can often read higher on the first measurement than manual BP methods.

After the 3 BP screenings, the study authors classified the subjects as normal (both systolic BP and diastolic BP < 90th percentile for age, height, and sex at first screening); prehypertensive (mean systolic BP or diastolic BP between the 90th and 95th percentiles on 2 of the 3 screens); stage I hypertension (mean systolic BP or mean diastolic BP ≥ 95th percentile but < 99th percentile); and stage II hypertension (mean systolic BP or mean diastolic BP ≥ 95th percentile on all 3 screenings and blood pressure > 99th percentile + 5 mm Hg on at least 2 screening occasions).

The study included over 6700 children screened, and 81.1% had normal BPs at the initial screening. After all 3 screening rounds, 3.2% of the children were classified as having hypertension. Eighty percent of those (2.6% of total) were classified as stage I hypertension. An additional 15.7% of the cohort were classified as prehypertension. All classes of hypertension were positively correlated with body mass index. (Increasing body mass index raised the chance of being classified as pre- or hypertensive.)

The study authors noted that having more than 15% of the children fall in the prehypertension range was concerning, especially given the relative lack of knowledge with regard to the long-term relationship between prehypertension and other health outcomes.

The study authors concluded that up to 20% of their sample were at risk for hypertension or had hypertension.

I reviewed this article mostly to remind readers about the 2004 guidelines (please see Related Links) and to review the stepwise approach needed in measuring BPs.[1] First, the guidelines suggest that automated methods may be used (after disregarding the initial read), but elevated BPs should be confirmed with manual measures. If the manual measures are lower, these are the values that should be used. Similar to prior standards, the patients should be screened at least 3 times before determining their final status.

The study authors noted very little difference in overall percentages in each status category regardless of how they handled the 3 measurements -- on the basis of 2 out of 3 (elevated or not), any one elevated, or just the final reading -- suggesting that "normal" BPs are normal, but any one elevated BP may place the patient somewhere "above" normal on the spectrum of BP.

Finally, the guidelines offer suggestions for how to intervene for each level. Except for patients with very high BP, the guidelines generally suggest attempts at lifestyle modification first, followed by pharmacotherapy if 6 months of lifestyle modification are not effective.



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