Home monitors can aid blood pressure control

Victoria Will (L) has her blood pressure checked by nurse practitioner Sapana Patel during a routine physical in New York March 22, 2010.

NEW YORK (Reuters Health) - Home blood pressure monitors can help people keep their blood pressure in check and possibly cut down on medication -- as long as the patients and their doctors put those home readings to good use, a new research review finds.

The analysis, of 37 international clinical trials, found that on average, adults with high blood pressure who were assigned to use home monitors shaved a few points off their blood pressure compared with counterparts who stuck with doctor's office measurements alone.

The home monitor users were also twice as likely to reduce the number of blood pressure medications they needed.

Researchers say the findings, reported in the journal Hypertension, should encourage people with high blood pressure to invest in a home monitor. The devices generally range in cost from about $25 to more than $100, depending on the features.

"Everyone who wants to know how well (their) blood pressure is controlled should monitor blood pressure at home," the study's lead author, Dr. Rajiv Agarwal of the Indiana University School of Medicine in Indianapolis, told Reuters Health in an e-mail.

He also likened blood pressure monitors to exercise treadmills, though. People may buy them with good intentions, but how they use them is what matters.

In their study, Agarwal and his colleagues found that home monitoring tended to work better when it was part of a general plan to adjust medications in response to the home readings.

The conventional way to do that is to bring your blood pressure readings to your doctor at each visit; some home monitors have memory storage that automatically records each reading and allows you to print out the information.

A few of the studies Agarwal's team reviewed tested so-called telemonitoring, in which wired or wireless technology is used to automatically send blood pressure readings to the doctor's office. Those studies tended to show greater effects on blood-pressure control than studies without telemonitoring.

Right now, though, telemonitoring is not commonly used for managing high blood pressure and studies are still investigating its value.

The findings are based on 37 clinical trials that included a total of 9,446 men and women with high blood pressure. In each, researchers randomly assigned some patients to use home blood pressure monitors and the rest to stay with office-based measurements. Most of the studies followed the participants for a few months to one year.

Overall, study participants using home monitors saw their blood pressure dip by 2 to 3 points, and most of the studies came out in favor of home monitoring over office-based measurements alone -- though the differences were generally small.

Patients with home monitors were also more likely to be able to cut down their drug regimen. In one of the larger trials, for example, 51 of 203 home-monitor patients reduced their number of medications, versus 22 of 197 patients without home monitors.

That, according to Agarwal's team, may be because home monitoring helps detect the "white coat effect" -- when a person's blood pressure spikes in the doctor's office.

Dr. Giuseppe Mancia, who co-wrote an editorial published with the study, agreed that home monitors are a good investment.

"I definitely believe that all (high blood pressure) patients should be advised by their physician to use a home BP monitor," Mancia, of the University of Milano-Bicocca in Italy, told Reuters Health in an e-mail.

He also pointed out, however, that patients should use the monitors only as often as their doctors recommend, and not become obsessive about checking their numbers. Obsessive checking could just spur anxiety, which could, in turn, boost blood pressure.

Mancia said people should also be sure to choose monitors that have been validated for accuracy according to international criteria. Certain professional groups, like the British Hypertension Society and the Association for the Advancement of Medical Instrumentation, test blood pressure monitors' reliability and maintain lists of validated monitors on their websites.

The current study was funded by the U.S. Department of Veterans Affairs. None of the researchers reports any financial conflicts of interest.

SOURCE: link.reuters.com/xaf69q Hypertension, online November 29, 2010.