People with hypertension who regularly monitor their own blood pressure tend to have lower numbers than those who don't use a home blood pressure monitor, a new review of past studies suggests.
The analysis showed self-monitoring was most successful when paired with extra resources for patients, such as online materials or phone calls with health workers.
"Self-monitoring allows individuals to take more ownership of their own healthcare and track themselves how they're doing," said Hayden Bosworth, who has studied that topic at Duke University Medical Center and the Durham Veterans Affairs Medical Center in North Carolina.
"If you eat five ham biscuits for breakfast … you can see the implications of that through your blood pressure in monitoring that relatively quickly, as well as if you exercise," he said.
"It's no different than tracking your own weight. You need to know, on a daily basis, how you're doing, what sets it off and are you going too high or too low."
Bosworth was involved in vetting the review's questions and content before it was finalized as part of an Agency for Healthcare Research and Quality panel.
He said measuring blood pressure at home may result in more accurate readings than when people are under stress at the doctor's office. It also gives patients and their doctors more numbers to review and consider when making treatment decisions.
For the review, Dr. Katrin Uhlig from Tufts Medical Center in Boston and her colleagues analyzed 52 studies that followed people monitoring their own blood pressure - with or without additional support - and those receiving usual care for hypertension.
In studies that looked at self-blood pressure monitoring alone, people who used the monitors had a systolic blood pressure (the top number in a blood pressure reading) that was 3.9 mm Hg lower than other patients and a diastolic blood pressure (the bottom number) that was 2.4 mm Hg lower at six months.
However, by one year there was no clear difference in blood pressure readings.
Among trials that paired self-monitoring with additional support, the benefits were clearer at one year: anywhere from a 3.4 to 8.9 mm Hg reduction in systolic blood pressure compared to people in usual care and a 1.9 to 4.4 mm Hg reduction in diastolic blood pressure.
Most of the studies did not look at whether medication use and long-term health were any different between self-monitors and non-self-monitors.
But even small drops in blood pressure have been tied to a lower risk of dying from heart disease or a stroke, Uhlig and her colleagues wrote Monday in the Annals of Internal Medicine.
High blood pressure is considered 140/90 mm Hg or above. About one in three adults in the U.S. has high blood pressure, according to the National Institutes of Health.
Bosworth said a typical blood pressure monitor costs about $40. He said self-monitoring may not be for everyone - especially people who might get anxious taking their own readings and drive their numbers up.
But, he added, "The reality is, for most people if they're taught how to do it adequately, they don't need to come in" to have it done in the doctor's office.
He said more research is needed to determine if the home monitors save more money in patient care than they cost, and to see which people may benefit most from using one.