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[The white coat effect during the first hour of ambulatory blood pressure]
Jian-feng Huang1, Jie Cao, Jian-xin Li
1Hypertension Center and Department of Evidence Based Medicine, Fu Wai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China.
Insights
The first hour of ambulatory blood pressure monitoring shows elevated readings due to the white coat effect, particularly in women. Excluding this initial hour improves ambulatory blood pressure monitoring accuracy.
Area of Science:
- Cardiology
- Hypertension Research
- Clinical Measurement
Context:
- Ambulatory blood pressure monitoring (ABPM) is crucial for diagnosing and managing hypertension.
- The initial period of ABPM may be influenced by patient anxiety, known as the white coat effect (WCE).
- Understanding WCE is vital for accurate interpretation of ABPM data.
Purpose:
- To investigate the white coat effect during the first hour of ABPM.
- To assess the impact of the first-hour elevated blood pressure on overall ABPM results.
- To determine if WCE differs between genders and age groups.
Summary:
- A study of 626 patients found significantly higher blood pressure readings in the first hour of ABPM compared to later intervals.
- The white coat effect was more pronounced in women than in men.
- No significant differences in the first-hour effect were observed across different age groups.
Impact:
- Suggests excluding the first hour of ABPM data from analyses to obtain more reliable clinical and research findings.
- Highlights the need for standardized ABPM protocols to account for the initial elevated readings.
- Improved accuracy in ABPM interpretation can lead to better hypertension management strategies.
Objectives:
To investigate the white coat effect during the first hour of ambulatory blood pressure and its effect on the ABPM.
Methods:
A total of 626 outpatients and inpatients (257 were male, 369 were female), whose ages ranged from 13 to 90 (average age: 55 years) were entered into this study. All subjects were taken measurements of clinic blood pressure. Ambulatory BP monitoring was applied to the nondominant arm between 8:30 to 9:29, and set the average BP value of this interval as the first hour blood pressure.
Results:
There was an obvious elevation of the first hour measurement than that of the other intervals of 24ABPM. The white coat effect (WCE) was greater in women than in men (average BP of 1(st) hour-average BP in daytime: (9.5 +/- 13.4)/(6.0 +/- 7.8) mm Hg (1 mm Hg = 0.133 kPa) vs. (5.5 +/- 11.9)/(4.2 +/- 7.8) mm Hg, P < 0.01), and there was no statistic significant difference was founded among different age groups.
Conclusion:
The first hour of ambulatory blood pressure monitoring is associated with significantly elevated blood pressure. We propose that improved ambulatory blood pressure monitoring recordings would be obtained in clinical practice, and more particularly in research applications, if 25 hours ambulatory blood pressure monitoring was carried out, excluding the first hour from the summary analyses.
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