While the use of medicines proven to save the lives of heart patients has shown steady improvement, investigators at the Duke Clinical Research Institute have determined that there is still much need for better physician prescribing of, and patient adherence to, life-saving medicines, particularly continued long-term use of these medicines.
The researchers said that for the most part, physicians and health care providers appear to be doing a reasonably good job of prescribing the appropriate medications to their heart patients at discharge from the hospital. However, the next major challenge is to better understand the factors that influence how consistently heart patients will continue to take their medicines, the researchers said.
The most glaring example highlighted by the researchers is aspirin, which was consistently used by only 71 percent of patients in their study.
"It is eye-opening to be reminded how much work we still have to do when in this day and age, only seventy-one percent of heart patients are taking aspirin," said Duke cardiologist Kristin Newby, M.D., lead author of a study whose results were published online Jan. 9, 2006, in the journal Circulation. "For a drug that is well-understood, inexpensive, easily available and fairly well-tolerated, we should see rates in the upper 90 percent.
"We also found that other drugs that have been proven to save lives are even less consistently used than aspirin, such as beta-blockers, cholesterol-lowering drugs and ACE inhibitors," Newby said. "Our analysis showed that consistent use of these medicines could lead to significant reductions in risk for patients with coronary artery disease."
Specifically, the researchers found that patients who were consistent in their use of aspirin saw a 42 percent reduction in risk of death, while beta-blocker use led to a 37 percent reduction and lipid-lowering medicines led to a 48 percent reduction. Patients who took all three saw a 33 percent reduction. Among a subgroup of the analysis, those with heart failure, consistent use of ACE inhibitors led to a 25 percent risk reduction.
For their analysis, the team used the Duke Databank for Cardiovascular Disease, which has collected detailed clinical information on its cardiac catheterization patients since 1969. Each Duke patient with coronary artery disease is contacted at least once a year following discharge from the hospital. Since 1995, medication use also has been collected.
In the period 1995 to 2002, the team identified 31,750 patients with documented coronary artery disease. That group was divided into those that did not have heart failure (71 percent) and those that did (29 percent).
"Among all the patients, the proportion of patients taking each agent and combinations of agents increased over the time of the study, with the peak for each occurring in 2002," Newby said. About 83 percent of patients reported taking aspirin, 61 percent beta-blockers, 63 percent lipid lowering drugs and 39 percent for all three together.
"However, when we looked at those patients who were taking the medications consistently, only seventy-one percent were taking aspirin," Newby said. "Only forty-six percent were consistent in their use of beta blockers, forty-three percent for lipid lowering drugs and twenty-one percent for all three."
For heart failure patients, use of ACE inhibitors peaked at 51 percent in 2002, with a 39 percent consistent usage rate, she said.
Paradoxically, the team found that those patients who would benefit the most from the consistent use of these medication were the least likely to be taking them.
"Those patients with heart failure, who were older, or who had other diseases had the worst overall consistent use," Newby said. "There are still doctors who are reluctant to prescribe these drugs to their sickest patients, maybe not realizing that potential side effects are far outweighed by the benefits. This represents a gap in our understanding - why is it that health care providers appear to fear treating these patients as aggressively as other patients?"
Newby's analysis is part of the Centers for Education and Research on Therapeutics (CERTs) demonstration program, a national initiative to conduct research and provide education that advances the optimal use of therapeutics, including drugs, medical devices, and biological products. The program, which consists of seven centers and a coordinating center, is administered as a cooperative agreement by the Agency for Healthcare Research and Quality (AHRQ), in consultation with the U.S. Food and Drug Administration (FDA). Duke is the research center for cardiovascular therapeutics, and also serves as the coordinating center for the national CERTs program.
"We as physicians have spent a great deal of time studying how best to treat our patients while in the hospital, so now we need to focus on better understanding the barriers to improved compliance outside of acute medical settings," Newby said. "This will be a much more difficult problem, since it involves so many different factors."
The Duke CERTs team is currently organizing a randomized clinical trial designed to better understand one facet of this complex problem. The team plans to work with community pharmacists to see if better communication between patients and health care providers, including the community pharmacist can lead to improved long-term adherence.
The American Heart Association estimates that 13.2 million Americans have a history of coronary artery disease and therefore are at risk of a new or recurrent cardiac event.
Other members of the Duke team were Nancy Allen LaPointe, Pharm.D., Anita Chen, Judith Kramer, M.D., Bradley Hammill, Elizabeth DeLong, Ph.D., Lawrence Muhlbaier, Ph.D., and Robert Califf, M.D.