White coat hypertension and blood pressure variability.

The objective of this cross-sectional study was to investigate blood pressure variability and pulse pressure in white coat hypertensives in comparison to established hypertensives and normal subjects. Four hundred and twenty patients were referred consecutively from general practice with newly diagnosed untreated essential hypertension. One hundred and forty-six control subjects were drawn at random from the Danish national register. Seventy-six patients from the former group were considered white coat hypertensive using a normalcy cutoff level of 135/90 mm Hg. Mean, standard deviation, and coefficient of variation of the blood pressures from the automated clinic readings, daytime, nighttime, and full 24-h periods were extracted from 24-h ambulatory blood pressure monitorings. Mean arterial pressure, pulse pressure, white coat effect, and dip were calculated in all three groups of subjects. The main findings were that white coat hypertensives did not differ significantly from normotensives regarding variability data except for the white coat effect. However, the white coat hypertensives had a significantly lower pulse pressure than the established hypertensives, according to clinic blood pressure and ambulatory readings. We conclude that white coat hypertension evaluated with indirect ambulatory blood pressure monitoring is not a state with a generally higher blood pressure variability than normotension or established hypertension. The patients with white coat hypertension have pulse pressure at the same level as normal controls, but significantly lower than established hypertensives.