FRIDAY, May 11, 2007 (HealthDay News) -- When it comes to daily drug therapy for heart patients, less may be more, a new study suggests.
Researchers developed a computer model to predict the cost and benefits of administering two drugs -- one to lower blood pressure and one to lower cholesterol -- either separately, or in a single-pill formulation, to two, 100,000-member groups with hypertension plus other cardiovascular risk factors.
The two medications were amlodipine, a blood pressure medication sold under the brand name Norvasc, and atorvastatin, a cholesterol-lowering medication branded as Lipitor. The combined formulation is called Caduet, and all three are available from Pfizer Inc., which provided funding for the study.
Under idealized, clinical trial conditions, where each individual was presumed to take his or her medication exactly as directed, both groups had the same number of cardiovascular events over four years -- 3,520. But the four-year medical costs were lower in the single pill group ($6,471 vs. $7,665), because the single pill formulation costs less.
When the two groups were "modeled" in "real-world" conditions, in which adherence to medication regimens isn't 100 percent, the number of predicted cardiovascular events jumped to 6,990 for the two-pill group, and to 6,859 for the single pill, with associated four-year medical costs of $6,543 and $4,993, respectively.
In other words, outside of a clinical trial setting, users of the single-pill formulation could expect slightly fewer cardiovascular incidents, and lower associated medical costs, than users of the two pills, said study author Timothy Smith, senior director of health economics and outcomes research at IMS Consulting in Falls Church, Va.
"In the language of cost-effectiveness analysis, this is a case where the two-pill therapy is dominated by the one-pill therapy," Smith said, "because the single pill costs less, and it is more effective because of improved compliance."
The study was expected to be presented May 11 at the American Heart Association's Scientific Forum on Quality of Care and Outcomes Research in Cardiovascular Disease and Stroke, in Washington, D.C.
According to Smith, the findings reflect the anecdotal understanding that the more medications a patient must take, the less likely he or she is to take them all correctly. "It is fairly well accepted that there is a pill burden," he said. "The more medications you take, the worse the compliance."
But, Smith added, the conclusions also are based on a computer model that used data from a former study using slightly different medications. So, the new findings must be validated, he said.
Dr. Paul S. Chan, a cardiovascular fellow at the University of Michigan Medical School, who has published several papers on cost effectiveness in medicine, called the new study "interesting." But, he noted, that besides not having been peer-reviewed, the study's primary conclusion -- that one pill is better than two -- has one "huge caveat."
Even if one pill saves money over two pills at the present time, that would not likely be true once one or both drugs lost patent protection.
"It's a very ingenious marketing ploy," Chan said. "Even though it saves money up front, it also ensures that patients will stay on the combination pill when, in the future, it might be cheaper to buy the meds separately."
For more on high blood pressure, visit the American Heart Association.