An easier way to detect 'white-coat' hypertension

You wouldn't describe my dad as an anxious person, not by a long shot. But that didn't mean he was immune to the "white coat" effect--namely, that his blood pressure would spike whenever a doctor or nurse approached him with a blood pressure cuff. Whether caused by nerves or anticipation, his reading would be high--which alarmed his doctors and baffled him, as he was sure his blood pressure wasn't normally so elevated. Finally, a doctor asked him to do his own readings at home, and guess what? His blood pressure was lower.

As many as 1 in 4 adults have "white coat" hypertension. This means their blood pressure goes up when they go to see their doctor but is normal at other times. If undetected, white coat hypertension can lead to a person being wrongly diagnosed with high blood pressure and having unnecessary treatment.

Now researchers have devised an alternative approach, which can be done in a doctor's office. And a new study suggests it may be as accurate as ABPM.

With the new method, a person sits alone in a quiet room for 30 minutes and their blood pressure is tested every five minutes, with the same device that's used in ABPM. The first blood pressure reading is discarded, as it may be falsely elevated, and then the rest are averaged to produce a final reading.

To check the accuracy of this approach, researchers recruited 84 people who had their blood pressure tested using the new method, followed by 24-hour ABPM (for the study, the researchers looked only at the daytime readings). They then compared these results with readings done by medical staff.

Their findings? Readings from the new method closely mirrored those from daytime ABPM, varying by less than 2 points on average. The researchers also found that the new method mostly matched ABPM in showing which patients had:

• White coat hypertension (high readings by medical staff, but normal blood pressure)
• Masked hypertension (normal readings by medical staff, but high blood pressure)
• Sustained hypertension (blood pressure consistently high)
• Normal blood pressure (blood pressure consistently in normal range).

This was a well-conducted study and its findings should be fairly reliable. However, the study was quite small and all the participants came from the same clinic. To know for certain whether this method can be reliably used in general practice, we need a larger study done in a variety of settings.

What you need to know

It's natural to feel a bit anxious during a doctor's appointment, and this can translate into falsely elevated blood pressure readings. If you're concerned that you might have white coat hypertension, be sure to mention this to your doctor. That way, you can have further testing to learn whether your blood pressure is indeed high and whether you would benefit from treatment. You might ask your doctor about this new in-office testing method. However, this approach is still experimental, so it may not be widely available.

--Sophie Ramsey, patient editor, BMJ Group

ConsumerReportsHealth.org has partnered with The BMJ Group to monitor the latest medical research and assess the evidence to help you decide which news you should use.

See our tips on measuring and controlling blood pressure. And see our Ratings of blood-pressure monitors. 

—Joel Keehn