Multiple BP readings better

Evaluating how well a person with high blood pressure (BP) responds to medicines requires multiple BP readings.

Blood pressure often rises at doctor appointments, a condition known as 'white coat' hypertension, so readings could also be taken by patients at home. Collecting just a few (five or six) blood pressure readings at home helps the doctor make much better decisions about whether the blood pressure is under control. Untreated, high blood pressure can lead to complications including stroke.

Researchers studied 444 US veterans with high blood pressure, about 90 percent of them men, with an average age of 64 years. All had been diagnosed with high BP about 10 years earlier. Their blood pressure was considered uncontrolled, even though most took multiple blood pressure-lowering medicines. The study compared blood pressure readings taken in three settings - at home, in a doctor's office, and at a clinical research setting - at the study start and again at 6, 12 and 18 months intervals.

It was found that the measurements varied widely. Only a third of them were consistently categorised as in or out of control by all three measures. Using just one reading as the basis for prescribing or adjusting blood pressure medication could endanger patients who suffer from 'white coat' hypertension. As many as six readings were needed to obtain the best estimate of true blood pressure and doctors could average the results.


Home monitoring of blood pressure has gained acceptance in recent years. About 43 percent of people with high blood pressure use home monitors. Those who buy a home blood pressure monitor should get it validated for accuracy by their doctors. Patients need to measure their blood pressure at different times of the day, and to sit and relax for five minutes before taking the BP reading.

This study confirms the need to improve both measurement technique and the number of BP measurements taken so that treatment could be based on more accurate information.