When it comes to treating high blood pressure, people may be more likely to stick with certain types of medication than others, a new study suggests.
In an analysis of 15 past studies, researchers found that on average, people were less likely to adhere to prescriptions of diuretics – a long used and cheap class of blood pressure drug sometimes referred to as water pills – than to relatively newer medications.
Patients were most likely to stick with angiotensin II receptor blockers, or ARBs – a group of drugs that includes names like valsartan (Diovan), candesartan (Atacand) and losartan (Cozaar).
Coming in second were ACE inhibitors, which include ramipril (Altace), lisinopril (Prinivel, Zestril) and captopril (Capoten).
Overall, diuretic users were about twice as likely to stop taking their medication as ARB users, researchers report in the medical journal Circulation.
The various classes of blood pressure drugs differ in how they work and in their side effects. And that could be one reason that adherence differs, according to the researchers, led by Dr. Ian M. Kronish of Mount Sinai School of Medicine in New York.
However, a researcher not involved in the study said the findings do not necessarily mean that a person will stick with an ARB longer, or that those drugs should be a first choice for treating high blood pressure, said Dr. Niteesh K. Choudhry, of Brigham and Women’s Hospital and Harvard Medical School in Boston.
In fact, Choudhry noted in an interview, national guidelines recommend diuretics as a “first-line” medication for high blood pressure, based on large-scale clinical trials showing their effectiveness.
“To me, that data still reigns supreme,” said Choudhry, who wrote an editorial published with the study.
“These findings don’t support abandoning what we’re doing now,” he added.
For the study, Kronish and his colleagues combined the results of 15 studies looking at people’s adherence to their blood pressure prescriptions. Most of the studies defined “adherence” according to whether people persistently filled their prescription over the study period – which in most was a year.
On average, 65 percent of ARB users stuck with their medication, versus 58 percent of ACE inhibitor users and 51 percent of diuretic users. Another class of drug, beta-blockers, had the lowest adherence, at 28 percent.
When the researchers weighed other factors – like patients’ age, race and income – both diuretic and beta-blocker users were about twice as likely to stop taking their medication as ARB users were.
Choudhry said it is “plausible” that diuretic users could be more likely to quit because of the medications themselves.
The drugs’ mode of action – helping the body get rid of water and salt – means frequent bathroom trips, and some people may be bothered by that.
In addition, Choudhry said, diuretics are older blood pressure drugs, and some patients (and doctors) perceive them as “not as good” as the newer ARBs and ACE inhibitors.
“But we know from large-scale studies that people do just as well on diuretics as they do on other drugs,” Choudhry said.
Nearly a decade ago, a huge clinical trial known as ALLHAT found that diuretics were more effective than other blood pressure medications at preventing heart failure – which was key in making them a first-choice drug for high blood pressure.
Choudhry said that a range of factors – from price to side effects—can affect any one person’s ability to stick with a blood pressure medication.
ARBs, for instance, are more expensive than other drugs, while ACE inhibitors can cause a chronic, bothersome cough.
“These are legitimate concerns,” Choudhry said, “and they are precisely the type of thing you need to bring up to your doctor.”
But people should not stop taking their medication on their own. “It’s very important to take the medication you are prescribed,” Choudhry said. “If you are having trouble, talk with your doctor.”
SOURCE: Circulation, online April 4, 2011.