Correlation of blood pressure readings from 6-hour intervals with the daytime period of 24-hour ambulatory blood pressure monitoring in pediatric patients.

Shorter-interval (6-hour) ambulatory blood pressure monitoring (ABPM) has been shown to correlate well with 24-hour ABPM in adults, but this has not been studied in children. The authors selected 131 patients aged 9 to 18 who underwent 24-ABPM from 2000-2008. Six-hour intervals beginning at different start times were compared with the daytime and 24-hour period, with subset analysis for normotensive and hypertensive patients. Concordance correlation coefficients (CCCs) were used to assess for agreement. Among normotensive patients, the mean difference between daytime and 6-hour intervals ranged from -0.1 mm Hg to 0.0 mm Hg for diastolic blood pressure (DBP) and -1.1 mm Hg to 0.6 mm Hg for systolic blood pressure (SBP) with CCCs of 0.88 to 0.93 for DBP and 0.93 to 0.96 for SBP. For hypertensive patients, mean difference ranged from -0.6 to 1.3 mm Hg for DBP and -0.8 to 1.1 mm Hg for SBP with CCCs of 0.89 to 0.98 for DBP and 0.86 to 0.95 for SBP. Shorter-interval monitoring correlates significantly with full daytime monitoring in children, allowing for assessment of blood pressure with improved convenience.