TUESDAY, Sept. 13, 2016 (HealthDay News) -- Nearly 5 million Medicare prescription drug enrollees aren't taking their blood pressure medication as directed, increasing their risk of heart attack and stroke, a new U.S. study found.
An analysis of 18.5 million Medicare Part D enrollees in 2014 found that 26 percent either skipped doses of their blood pressure medication or stopped taking the drugs entirely, according to the study from the U.S. Centers for Disease Control and Prevention.
"That's particularly troubling, because other research indicates that up to 25 percent of new prescriptions for blood pressure medicine are never even filled in the first place," CDC Director Dr. Tom Frieden said. "Of those prescribed those regimens, maybe a quarter don't even start them, and now we're finding that another quarter don't continue them."
Heart disease and stroke kill 800,000 people every year in the United States, accounting for about one out of every three deaths, Frieden said. Uncontrolled high blood pressure also has been associated with dementia and mental decline later in life, he added.
Seventy percent of U.S. adults ages 65 and older have high blood pressure (140/90 or higher), but just a little more than half have their blood pressure under control, according to the CDC.
Heart-healthy lifestyle changes can help, but eating right and exercising often aren't enough to bring blood pressure down to healthy levels for many people, Frieden said.
"Critically, medications will be necessary for the vast majority of people with high blood pressure, but they only work if they are taken," he said.
The percentage of drug non-adherence varies among racial and ethnic groups -- more than one-third of blacks, Hispanics and American Indians versus roughly one quarter of whites or Asian/Pacific Islanders, the CDC researchers found.
People living in the South -- the so-called "Stroke Belt" -- had the highest rate of non-adherence in the nation, Frieden noted.
"This is another call to action for this part of the country, knowing that they are typically at higher risk for having strokes and heart attacks," said lead researcher Matthew Ritchey, an epidemiologist with the CDC's division for heart disease and stroke prevention.
Medication class also made a difference, with diuretics (water pills) abandoned more often than other drugs, the study found.
Lower-income individuals also were less likely to take their blood pressure medication as directed. About 32 percent of people with a low-income subsidy did not adhere to their regimen, compared with one-quarter of people with no subsidy, the researchers found.
Given this, insurers can help by reducing or eliminating copays on blood pressure medication, Frieden said.
"We have learned repeatedly that any copay will reduce medication use, even among those who don't have substantial financial constraints," he said.
Frieden also called on doctors and health systems to help encourage adherence by making blood pressure medication regimens as easy-to-follow as possible, and checking in with patients to see if they're taking their drugs as directed.
"Everyone needs to understand how crucially important medicines to control blood pressure are," Frieden said. "Medicines that control blood pressure can save your life. They can prevent you from having a stroke or heart attack. It's important that you take them."
The study findings were published Sept. 13 in the CDC's Morbidity and Mortality Weekly Report.
For more on controlling high blood pressure, visit the American Heart Association.