Home Blood Pressure Readings “Unmask” Heart Risks

High blood pressure readings at home rather than a clinic may identify likely heart trouble

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) High blood pressure can be a “masked” villain. Readings at a clinic may show normal blood pressure levels, while home readings may give a more accurate view of cardiovascular health.

A new study found that patients who had normal blood pressure readings in a clinic but elevated readings at home (called masked hypertension) faced a greater likelihood of death, heart attack and stroke compared to those who had normal readings both at a clinic and at home.

"Keep track of your blood pressure."

Jan Staessen, MD, head of the Division of Hypertension and Cardiovascular Rehabilitation in the Department of Cardiovascular Diseases at the University of Leuven in Belgium, and colleagues analyzed data on 5,008 patients to gauge the effects of masked high blood pressure.

Hypertension, or high blood pressure, raises the risk of heart attack, stroke and heart disease. While many individuals only get their blood pressure taken in a medical setting, blood pressure readings can also be taken at home.

Dr. Staessen and colleagues noted that self-measured home blood pressure readings were lower than clinic measures by an average of about 7.0 mm Hg/3.0 mm Hg than the standard measure of blood pressure.

The top number in a blood pressure measurement shows systolic pressure, the maximum force of the blood in the arteries. The bottom number shows the diastolic pressure, or the pressure measurement when the heart is relaxed. The American Heart Association defines normal blood pressure as less than 120 for systolic and less than 80 for diastolic. Prehypertension or “high-normal” is higher than 120/80 but lower than 140/90. High blood pressure is 140/90 and above.  

Dr. Staessen and team discovered 67 people who had an average optimal blood pressure of less than 120/80 mm Hg in the clinic but still had high-normal blood pressure of more than 130/85 when measured at home. A total of 187 people had a 120/80 mm Hg average reading in the clinic but still had high-normal blood pressure at home.

Also, there were 315 people with high-normal blood pressure readings in the clinic who had masked hypertension in home readings.

After a median follow-up of just over eight years, 522 study subjects died, and 414 had a fatal or nonfatal cardiovascular episode.

The researchers calculated that patients with optimal blood pressure in the clinic but masked high blood pressure faced a death rate of more than twice that of those with optimal pressure in the clinic without masked high blood pressure. Compared to this group, patients with normal in-clinic readings but with masked high blood pressure had a 57 percent greater likelihood of death and those with high-normal blood pressure in the clinic but masked high pressure had a 54 percent higher chance of dying.

The authors of this study observed that patients with masked hypertension were more likely to be male, older and more obese. They were also more likely to smoke and to have diabetes or a history of cardiovascular disease.

“We suggest that in individuals at risk for masked hypertension, home blood pressure monitoring should be included in the strategy of primary prevention of cardiovascular complication,” these authors wrote.

Sarah Samaan, MD, cardiologist and physician partner at the Baylor Heart Hospital in Plano, Texas, told dailyRx News, “We often hear about ‘white coat hypertension,’ or blood pressure that is high in the doctor's office, but normal at home. However, masked hypertension, or high blood pressure at home but normal pressure in the office, is important as well, and more common than many people realize.”

She added that for those at risk of hypertension, checking home blood pressures from time to time can help identify a problem before serious consequences occur.

“When we physicians see patients in the office, we usually have a single blood pressure reading to rely on,” said Dr. Samaan. “It makes much more sense to have a series of readings over time, so we can detect any important trends. One to two readings per week, at different times of the day, is usually all that is necessary. Bring that information with you to your next office visit to help your doctor optimize your care."

This study was published in January in PLoS Medicine.

This study was funded by numerous foundations and government organizations in Europe and Japan.

The authors declared no conflicts of interest.

Review Date: 
January 21, 2014
Last Updated:
January 22, 2014