Approximately one in four Americans has high blood pressure , which can lead to heart attack , stroke , and other cardiovascular complications. Fortunately, high blood pressure responds well to treatment, including lifestyle changes (i.e., exercise, diet changes, weight loss) and/or blood pressure-lowering medications.

A blood pressure measurement is part of a routine physical examination. This test can help your doctor determine whether you need to make significant lifestyle changes or begin or adjust blood pressure medications. The quality and accuracy of home blood pressure monitoring devices have improved dramatically and are readily available. As a result, more and more people with high blood pressure are beginning to monitor their own blood pressure at home. But are these people more likely to gain control over their blood pressure as compared to those who only have it tested in their doctor’s office?

A new study in the July 11, 2004 issue of the British Medical Journal found that people who monitored their blood pressure at home had greater reductions in blood pressure measurements and were more likely to achieve their target blood pressure than people who relied office-based monitoring.

About the Study

For this study, researchers compiled data from 18 randomized controlled trials that evaluated the effects of blood pressure monitoring in the home versus a clinical setting. Combined, these studies included 1,359 people who performed home blood pressure monitoring (home group), and 1,355 people who had their blood pressure monitored in a clinical setting (clinical group). All participants had high blood pressure.

The researchers used data from these studies to assess whether home blood pressure testing was associated with changes in blood pressure or the likelihood of meeting target blood pressure numbers.

The Findings

Overall, this analysis found that home monitoring improved blood pressure control. Specifically, the researchers found that home blood pressure monitoring was associated with:

  • A 4.2 mm Hg reduction in systolic blood pressure (the top number)
  • A 2.4 mm Hg reduction in diastolic blood pressure (the bottom number)
  • A 10% greater likelihood of reaching their target blood pressure

However, the researchers detected a “publication bias” in these studies. A publication bias occurs when studies that find an effect are more likely to be published than studies that find no effect. After controlling for this bias, reductions in blood pressure associated with home monitoring were estimated to be 2.2 mm Hg and 1.9 mm Hg for systolic and diastolic blood pressure, respectively. Although these changes are statistically significant, clinically speaking, they are still relatively small.

How Does This Affect You?

The results of the study suggest that home blood pressure monitoring increases blood pressure control in people with high blood pressure. Another study in the March 17, 2004 issue of Journal of the American Medical Association also supported the use of home blood pressure monitoring. This study found that home blood pressure monitoring was more reliable than clinical monitoring for predicting patients’ risk of cardiovascular disease.

While both of these studies are compelling, another study in the February 25, 2004 issue of the Journal found while making treatment decisions based on home versus office-based blood pressure measurement decreased medications and modestly lowered costs, it also resulted in slightly worsened blood pressure control.

All findings considered, the best advice is to have your blood pressure measured regularly at your physician’s office, but consider supplementing these measurements at home if you have high blood pressure. Home blood pressure monitoring can help your doctor see how much your blood pressure changes during the day or if your blood pressure medication is working. It can also help detect and avoid “white-coat syndrome” where your blood pressure is higher in your doctors office than elsewhere.

To get an accurate reading at home, the American Academy of Family Physicians suggests you do the following before you measure your blood pressure:

  • Rest for 3-5 minutes without talking
  • Sit comfortably, with your legs and ankles uncrossed and your back supported
  • Sit still and place your arm on the table, level with your heart
  • Wrap the cuff around the upper part of your arm (snugly, but with enough room to slip one fingertip under the cuff)
  • Make sure the bottom edge of the cuff is one inch above the crease of your elbow

Optimally, your blood pressure should be less than 120 mm Hg systolic, and less than 80 mm Hg diastolic.