Frequent Blood Pressure Checks May Trump Doctor Test

Ambulatory blood pressure monitoring may provide more accurate results than a clinical test

(RxWiki News) Having high blood pressure in a test at the doctor's office may not mean you have it all the time. Monitoring blood pressure outside the doctor's office, however, may lead to more accurate results.

New recommendations from the US Preventive Services Task Force (USPSTF) say high blood pressure readings in the doctor’s office should be confirmed with ambulatory blood pressure monitoring (ABPM).

The task force wrote in its report that "Our evidence review shows that overdiagnosis of hypertension from unconfirmed office-based screening could result in unnecessary treatment in a substantial number of persons."

A blood pressure check is a routine but important part of nearly every medical exam. However, patients may have high readings for a variety of reasons. “White coat hypertension,” for instance, can result from anxiety during the actual doctor’s visit.

A blood pressure reading in the doctor’s office can be much different from a reading done during normal activities. An ambulatory blood pressure monitor is a small device about the size of a portable radio. The patient also wears a blood pressure cuff on one arm. The machine records the patient’s blood pressure every 15 to 30 minutes throughout the day and night.

Patients can have very high blood pressure without any symptoms, so regular blood pressure checks are the best way to identify a problem, the USPSTF said.

"We found no evidence of other serious harms of blood pressure screening," the task force wrote. "This updated review for the U.S. Preventive Services Task Force finds that ABPM predicts long-term cardiovascular outcomes independent of office blood pressure screening measurements. Accordingly, use of ABPM can help avoid misdiagnosis and overtreatment of persons with isolated clinic hypertension."

One of every three US adults has high blood pressure, according to the USPSTF. High blood pressure can increase the risk of other conditions like heart disease, kidney failure and stroke. Although treatment is important for those who do have high blood pressure, medications can have side effects and treatment should not be used unless necessary, the USPSTF noted.

The USPSTF is an all-volunteer panel of national experts in prevention and evidence-based medicine. The task force performs a yearly review of current evidence to make health recommendations for doctors and patients.

This year, the task force assessed past studies to determine whether taking a patient’s blood pressure in the doctor’s office was the best way to identify high blood pressure. This research showed that an office blood pressure reading was not a good predictor of chronic high blood pressure. The USPSTF now recommends ABPM outside of the doctor’s office to confirm abnormal readings.

ABPM may eliminate the “white coat” problem. It also offers repeated blood pressure readings over the course of 24 hours rather than the single reading in the doctor’s office, the report authors said.

In addition to the recommendations for ABPM, the task force members noted that more frequent rescreening is important for some patients. Patients who had readings in the high-normal range and those who were older were more likely to develop high blood pressure over time. Blacks and people who were overweight were also at higher risk than the general population.

The task force said doctors should focus their efforts on ensuring blood pressure readings are accurate. People who have blood pressure risk factors should be rescreened more often, although the task force did not suggest a specific time frame for rescreening.

Although a dangerously high blood pressure should not be ignored, in most cases, higher-than-normal readings should be confirmed by ABPM, the task force said.

This report was published online Dec. 23 in Annals of Internal Medicine.

The primary funding source for the USPTF is the Agency for Healthcare Research and Quality (AHRQ). Report authors Dr. Piper, Ms. Evans, Ms. Burda, Dr. O’Connor and Dr. Whitlock received grants from the AHRQ during the study. Dr. Margolis received grants from the AHRQ during the study and grants from the National Heart, Lung and Blood Institute outside the study.

Review Date: 
December 19, 2014