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STUDY LOOKS AT WHITE COAT BLOOD PRESSURE EFFECT
blood pressure cuff

November 16, 2021 - The white coat blood pressure effect occurs when blood pressure readings run higher in a clinical setting as opposed to another setting like the patient's home. It is estimated that up to 20% of people diagnosed with stage I hypertension actually have white coat hypertension.

A small study published in the journal Hypertension took 18 people with mild-to-moderate untreated hypertension and measured their blood pressure multiple times over the course of 10 minutes with an automated cuff. The readings were first done in the absence of a doctor and then in the presence of a doctor. When the doctor was present, average blood pressure rose from 148/98 to 155/106 mmHg. When the doctor was absent, average blood pressure declined from 146/97 to 140/93 mmHg. Heart rate and sympathetic nerve activity (measured through the skin) were also elevated with the doctor present. [PubMed abstract]

While this study is small, its findings are significant. The peak difference in systolic blood pressure between the unattended and attended readings was 15 mmHg; this discrepancy could easily mean the difference between a lifelong prescription for an antihypertensive or not.

Current guidelines state that patients with blood pressure readings less than 180/110 mmHg should monitor their blood pressure for weeks to months before arriving at a diagnosis of hypertension. Home blood pressure machines are now easier than ever to use, and many connect to smartphones so that readings can be emailed to a doctor. Patients should also follow proper measurement techniques, something that is rarely done in clinics.

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