Home Blood Pressures 
Identify White Coat Hypertension and Help Blood Pressure Control

By Alan Peterson, M.D.

If your physician asks you to obtain a home blood pressure monitor, it is because he or she is trying to get a better grasp of your blood pressure situation.  Many times patients come to the office and have elevated blood pressures only to find out that these may be normal or certainly lower than the office values when taken at home.  This has been labeled “White Coat” hypertension with the thought that when you come to the doctor’s office there are many reasons that you might be anxious and this in fact might increase the blood pressure artificially. 

Many health care providers aim for systolic (that’s the upper number of the blood pressure) at 135 or below at home.  This assumes that you have no underlying diseases that require lower pressure than this.  (For example, we do like blood pressures in diabetics at home to be less that 130.)

By differentiating white coat from true hypertension, providers avoid unnecessary anti-hypertensive prescriptions and can sometimes decrease the frequency of office visits.  Patients can be spared the expense and potential side effects of treatments that they don’t necessarily need.  Frequently medications are needed but at lesser doses.

A recent article in the British Medical Journal concluded that “the ‘white coat’ effect is important in diagnosing and assessing control of hypertension in primary care and is not a research artifact.  Because of this white coat effect it is time to stop using high blood pressure readings documented by health care providers to make decisions about treatment”.  The article suggests that home blood pressure is a better indicator of true risk and of the response to treatment.

Improving blood pressure control in treated hypertensives is the other side of the coin.  Among treated members with poor blood pressure control, the percent of patients at goal jump from 33% to 56% after just 1.8 months of assessing and adjusting anti-hypertensive therapy using home blood pressure monitoring data. 

 Indications for a home blood pressure monitor can include newly diagnosed hypertensive patients, initiating and adjusting anti-hypertensive medication, poor blood pressure control with medication, diabetes with poor blood pressure control, pregnancy with hypertension, or other reasons as determined by your healthcare provider. 

The physician can suggest the frequency and time of day that the patient monitor their pressure.  Some patients just have high blood pressure, for example, in the morning.  Some people just have high blood pressure in the evening.  Other people have high blood pressures all day or just at various times of the day.  It is, therefore, important especially when one begins to take home blood pressures, to check it at various times of the day.  If there is a time identified that shows the pressure always being elevated, that pressure should be checked frequently to determine if medication is decreasing the pressure at that time.

 It is true that most people in the United States do not have controlled blood pressure even when it is identified.  On the other hand, there are those who may have blood pressure that is over treated because the pressures are only gathered in the doctors office.  Please take “to heart” suggestions from your physician to obtain a home blood pressure monitor, if he or she suggests it.

Discuss with your physician which brand of monitor might be suggested for both ease of use and best quality.  Obviously, if your arm is too large for a regular cuff, it is important to purchase the proper sized cuff, ie, a larger cuff.  If you are using a cuff that is too small for your arm, you can get blood pressures that are falsely elevated.  Again this is something that your physician can help you determine.