The reproducibility of serial measurements of ambulatory blood pressure monitoring (ABPM) has not been well explored in children. We performed 24-h ABPM in 59 subjects (38 boys) aged 8-19 years with repeatedly elevated casual blood pressure (BP).
According to the results of ABPM, the individuals were divided into a hypertensive group (mean 24-h systolic or diastolic BP > 95th percentile for height, n=28) and a normotensive group (n=31). No antihypertensive agents were given.
Both groups were reexamined after 1 year. In the hypertensive group, systolic and diastolic BP dropped significantly by an average of 2.1-4.5 mmHg, when measured either during the daytime or over 24 h, but not at nighttime.
In the normotensive group, only small BP changes were observed except for a significant increase in systolic BP at night. At the repeat examination after 1 year, 54% of the originally hypertensive subjects were defined as normotensive and 23% of the originally normotensive subjects as hypertensive.
The study indicates that a single ABPM measurement is not sufficient for definitive classification of young individuals into hypertensives or normotensives.