Abstract
Background:
There are limited studies that explore the rate of existent uncontrolled hypertension versus a significant white-coat effect. Likewise, few studies have described the physician's response to the results of an ambulatory blood pressure monitoring (ABPM) study.
Objective:
To determine the percentage of treated hypertensive patients referred for ABPM based on discrepant office and home blood pressures who had achieved goal blood pressure and to determine the degree of white-coat effect in these patients.
Methods:
Medical records of 222 consecutive patients were reviewed. Patients without a clinic visit since a medication change and those with <70% valid readings on ABPM were excluded. The proportion of patients at their goal blood pressure during ABPM was determined. Clinic blood pressure readings prior to ABPM were compared to daytime ABPM readings to calculate the white-coat effect. The percentage of patients whose blood pressure decreased by 10% or more in the night interval versus the daytime period was calculated. Changes to antihypertensive therapy were determined for the 6-month post-ABPM period.
Results:
One hundred ninety-three patients met the inclusion criteria. Mean (SD) clinic blood pressure was 158/77 (13/10) mm Hg, compared to mean daytime ABPM readings of 127/70 (12/9) mm Hg. Sixty-seven percent of patients were at goal blood pressure. The mean white-coat effect was 31/7 (16/9) mm Hg and was significantly greater in patients who were at goal versus those who were not (p < 0.01). A 10% or higher overnight dip occurred in 28% of those at goal. Therapy was not escalated 6 months after ABPM in 91% of patients who were at goal during the test despite a mean post-ABPM clinic blood pressure of 151/74 mm Hg.
Conclusions:
The majority of patients with incongruent clinic and home blood pressure readings were at goal after ABPM evaluation. Further study is needed regarding demographic or clinical characteristics that can be used to help predict which patients may be experiencing a significant white-coat effect and are actually at goal in an ambulatory setting.
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