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Studies have found that as many as 20 percent of people with high blood pressure in office screenings have “white coat” hypertension — which means they have elevated blood pressure only at the doctor’s office. Cummings said 24-hour checks of patients at his clinic have found almost 30 percent have “white coat” hypertension and don’t necessarily need medication.
Similarly, office blood pressure tests miss as many as 10 to 15 percent of patients with “masked” hypertension that does require treatment.
Zoss appears to have been a “white coat” case, although he has a family history of hypertension and one day could have the real thing.
Jerry Lutgen, of St. Paul, ended up with a different result. After monitoring his calories and running and swimming more, the 66-year-old reduced his blood pressure to the point that a standard office reading had him at healthy levels. Then he agreed to a 24-hour test — and found that he still had high blood pressure and would need to continue medication.
“I thought I had cleaned up my act enough that I was going to be free from blood pressure medication,” Lutgen said, “but the good news is that I’ve reduced it.”
He said he wonders whether more regular home monitoring would be as effective as the 24-hour test, because he, too, said the device was a nuisance when he was sleeping.
But periodic home monitoring doesn’t track blood pressure when people sleep, Cummings said, whereas 24-hour monitoring provides vital overnight data. Typically, blood pressure dips when people sleep. But for a small share of people with hypertension, blood pressure stays cranked up overnight. Cummings said studies have found that these people might be at the highest risk of complications from hypertension.
Cummings wants to make an economic case for 24-hour testing, also called “ambulatory” blood pressure monitoring, in primary care clinics. In the time that the telephone has evolved from a wooden box to a hand-held supercomputer, Cummings said, there has been little change in the standard blood pressure cuff, which was invented in the late 1800s.
Doctors, however, are unlikely to use the new devices unless insurers expand coverage. The federal Medicare program for seniors mostly covers 24-hour studies to confirm “white coat” hypertension — a paradox in that patients don’t know they have “white coat” cases until after the studies. Other insurers only cover the tests to confirm office readings or if recommended by cardiologists.
Increased use of the devices in primary care will be more likely if the U.S. Preventive Services Task Force recommends 24-hour monitoring in some way. The task force is two to three years from updating its guidelines on blood pressure screening, but it is expected to review ambulatory screening, said Dr. Karen Margolis, a researcher for Bloomington-based HealthPartners who is on the task force’s blood pressure screening committee.
Margolis said 24-hour testing is considered the “gold standard” for measuring blood pressure: “It may be the best approximation of truth that we have without sticking a catheter in somebody’s arteries.”
But when the 24-hour tests are worth the additional cost and when they are overkill is unclear. It’s also unclear how they could identify more “masked” hypertension cases unless they were given to all patients, regardless of blood pressure.
“It’s a big commitment,” Margolis said. “Some people find it very disruptive having this thing blowing up on your arm as you sleep.”
Jeremy Olson • 612-673-7744