Racial aspects of ambulatory blood pressure

Ambulatory blood pressure measurements, recorded by a Del Mar Pressurometer IV, were performed in 71 patients (25 blacks and 46 whites) with documented essential hypertension (supine diastolic blood pressure 95-119 mmHg) after four weeks of placebo treatment. Each 24-hour ambulatory BP measurement was calibrated with manual measurements within 5 mmHg and was repeated according to the daily conditions (work status) of the original recording. Ambulatory BP measurements were recorded every 15 minutes over 24 hours on two separate occasions one week apart. The mean of two 24-hour measurements was the value for the individual patient. Analyses of variance indicated no significant difference in the mean age, height, weight, 24-hour ambulatory systolic or diastolic BP, 8 am to 12 noon systolic or diastolic ambulatory BP, or 12 midnight to 4 am ambulatory systolic or diastolic BP for blacks versus whites. Among the subset of females, the 20 blacks were older than the 23 whites. Despite this age difference, there was no significant difference in height, weight or 24-hour, 8 am to 12 noon, or 12 midnight to 4 am ambulatory BP measurements. Therefore, this study does not support a racial difference in the level of ambulatory blood pressure measurement in these hypertensive patients.