Out-of-office blood pressure in children and adolescents: disparate findings by using home or ambulatory monitoring

BACKGROUND: The validity of home blood pressure (HBP) measurements in children has not been evaluated, although in clinical practice such measurements are being used. This study compares HBP, with clinic (CBP) and daytime ambulatory blood pressure (ABP) in children and adolescents. METHODS: Fifty-five children and adolescents aged 6 to 18 years were evaluated with CBP (three visits), HBP (6 days), and daytime ABP. Mean age was 12.3 +/- 2.9 (SD) years, 33 boys. According to the Task Force CBP criteria, 26 were hypertensives, 6 had high-normal BP (hypertensive group), and 23 were normotensives (normotensive group). RESULTS: In the hypertensive group, CBP was 130.8 +/- 7.6/72.5 +/- 8.1 mm Hg (systolic/diastolic), HBP 118.9 +/- 6.3/73.7 +/- 6.7, and ABP 130.8 +/- 8.1/75.5 +/- 8.3. In the normotensive group, CBP was 112.8 +/- 8/63.1 +/- 6.3, HBP 106.7 +/- 8.4/67.2 +/- 5.2, and ABP 123.9 +/- 7.2/72 +/- 4.3. Strong correlations (P < .001) were observed between CBP-HBP (r = 0.73/0.57, systolic/diastolic), CBP-ABP (r = 0.59/0.49), and HBP-ABP (r = 0.72/0.66). In normotensive subjects, ABP was higher than both CBP and HBP for systolic and diastolic BP (P < .001). Furthermore, systolic HBP was lower than CBP (P < .01), whereas the opposite was true for diastolic BP (P < .05). In hypertensive subjects systolic HBP was lower than both CBP and ABP (P < .001), whereas CBP did not differ from ABP. For diastolic BP no differences were found among measurement methods. CONCLUSIONS: These data suggest that, in contrast to adults in whom HBP is close to the levels of daytime ABP, in children and adolescents HBP appears to be significantly lower than daytime ABP. Until more data become available, caution is needed in the interpretation of HBP in children and adolescents.