High Blood Pressure: Screen Test
In previous columns I have discussed recommendations made by the U.S. Preventive Services Task Force (USPSTF). This is a quasi-governmental group of medical professionals that looks at the value of screening tests to detect many diseases and conditions. They consider both benefits and harms from testing and screening methods, including both the amount of false positive and false negative results, and the resultant harms or benefits to the health outcomes of individuals. Recently, the Journal of the American Medical Association published the results of the USPSTF recommendations for screening for high blood pressure (hypertension) in individuals 18 years of age and older.
Hypertension (HTN), which is present in about 45% of people in the U.S., is one of the most important risk factors for cardiovascular disease (CVD), which includes heart attacks and strokes. Blood pressure can be modified by both lifestyle changes and pharmaceuticals.
Traditionally, office-based screening for HTN has been the standard of care here in the U.S. for decades, however office-based methods may misclassify or misdiagnose individuals, especially in cases of “white-coat syndrome” or masked HTN. Recent research, recognizing this fact, has looked at the benefits of using out-of-office and novel office-based measurement methods. In my own experience, since prescribing medications should always be the last method of treatment, I would routinely recommend that a patient with a high blood pressure reading in the office should obtain a home blood pressure monitor. Then, once the patient brought the monitor into the office to check its accuracy, we would use the monitor’s results rather than the in-office results to assess whether the patient truly had HTN and, if present, how it should be treated.
It should come as no surprise that the USPSTF found convincing evidence that office-based screening for HTN and treatment of HTN for those 18 years-of-age and older has substantial net benefits and few major harms and it significantly reduces the risk for and incidence of CVD. They did acknowledge, however, that a one-time screening for HTN had low sensitivity for detecting HTN, meaning that multiple screenings are recommended, including home-based screenings, prior to arriving at a diagnosis of HTN and initiation of treatment for it. While the USPSTF does not make recommendations on what blood pressure readings constitute a diagnosis of HTN, the American Heart Association and other professional associations do set those limits. Currently, most experts agree that blood pressure should be 140/90 or below, and in some cases, for example in those with heart disease, 130/80 or below. Some experts recommend 130/80 for all, however, doing so would greatly expand the number of people with the diagnosis of HTN, and would also greatly expand the number of individuals being treated for it.
As far as treatment of HTN goes, medication should usually be the last resort. Lifestyle changes come first, for example cessation of smoking, weight loss, and dietary changes. Treatment should not begin with just one BP reading, and if your in-office reading is high, you should discuss using a home monitor with your doctor. The American Medical Association has a list of validated blood pressure devices. That list can be found at: www.validatebp.org
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By Peter Galvin, MD