Ambulatory blood pressure in prehypertensive children and adolescents.

BACKGROUND: Prehypertension is defined as blood pressure (BP) ≥ 90 th percentile, or ≥ 120/80 mmHg, but <95th percentile for age, sex, and height. Since the definition is made by conventional BP measurements and office BP can be quite variable, we studied whether prehypertension could be differentiated by ambulatory BP monitoring from normotension or hypertension (HTN) in children and adolescents. METHODS: One hundred and fifty-eight children (84 boys and 74 girls, aged 6-17 years, median 12) were studied. According to the office BP values, they were divided into normotension (80), prehypertension (20), and HTN (58). RESULTS: Systolic BP index and systolic daytime ambulatory BP (ABP) were significantly higher in prehypertensive patients than in normotensives and lower than hypertensives. When daytime ABP was used to diagnose HTN, four normotensive (5.0%), four prehypertensive (20.0%), and 27 hypertensive (46.6%) patients had HTN. Thus, in patients with prehypertension, the prevalence of masked HTN is significantly higher than in those with normotension. On the other hand, the prevalence of daytime ambulatory HTN is significantly lower, i.e., white-coat effect is more frequent, compared with hypertensive patients. CONCLUSION: Prehypertension lies between normotension and HTN in ABP values as well and is a good candidate for identifying masked HTN. Our data emphasize the importance of identifying prehypertension in children and adolescents.