Background: Information on the relationship between ambulatory blood pressure (ABP) and concurrently office blood pressure (BP) values in youth still suffers from limitations. We provide information on the differences between office BP and ABP, the factors related, and the clinical implications.
Methods: Three thousand six hundred ninety matched measurements of office BP and ABP on the same day, from 2390 children, aged 5 to 15 years, of both sexes were eligible. Office BP was measured using an oscillometric device (Omron 705 IT) and 24-hour ABP using oscillometric SpaceLabs 90207. Average of office, 24-hour, daytime, nighttime, systolic, and diastolic BP and heart rate was calculated. BP categories according to the European guidelines and phenotype of mismatch office BP versus ABP were defined.
Results: Both daytime systolic and diastolic BP were higher than office BP with a progressive reduction of the differences from 5 to 15 years. The office minus daytime BP differences were the largest in normotensive subjects, less at high-normal, and reversed in hypertensive ones, independently of age and weight status. White coat and masked hypertension covered no more than 13.6% at all ages.
Conclusions: In youth, it is inaccurate to obtain reference values for ABP by extrapolating from office BP values. The differences between office BP and ABP are minimal in children with office BP values in the range of hypertension, reinforcing the recommendation to use ABP measurement at the time to confirm hypertension.
Keywords: adolescent; child; heart rate; masked hypertension; white coat hypertension.