Published: May 16, 2004
Updated: Nov. 3, 2004
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By Duke Medicine News and Communications
WASHINGTON -- While the use of inexpensive aspirin and beta blockers by heart patients to prevent death has shown steady improvement, Duke University Medical Center cardiologists believe there is still much room for improvement, particularly in consistency of long-term use.
The medical community needs to focus its attention on educating physicians and patients on the importance of taking these medications on a long-term basis, said the cardiologists. While many clinical trials have consistently proven the ability of aspirin and beta blockers in forestalling future heart attacks, the new Duke analysis is the first to link consistent use of these drugs with improved outcomes.
The researchers found that consistent use of these drugs led to risk reductions of greater than 40 percent.
"Although most studies have documented the use of these evidence-based medicines while patients are in the hospital and at discharge, very few have actually documented the patterns of use once patients return to their communities," said Duke Clinical Research Institute cardiologist Kristin Newby, M.D. She presented the results of the Duke analysis May 16, 2004, at the American Heart Association's 5th scientific forum on Quality of Care and Outcomes Research in Cardiovascular Disease and Stroke.
"This is one of the first and largest to evaluate the long-term usage trends for these important preventative medications," Newby said.
Newby was able to perform this analysis because the Duke Databank for Cardiovascular Disease has been collecting detailed clinical information on all its cardiac catheterization patients since 1969. Every Duke heart patient with coronary artery disease is contacted once a year following discharge from the hospital. Since 1995, researchers began asking detailed questions about medications.
Specifically, the researchers found that 59 percent of patients were taking aspirin in 1995, increasing to 83 percent in 2002. As for beta blockers, the percentage of patients taking the medication increased from 34 percent to 61 percent. Those taking both medications increased from 24 percent to 54 percent. However, only 72 percent of patients consistently took aspirin over this period, only 46 percent a beta blocker and only 36 percent both drugs.
The analysis also found that patients who consistently took aspirin had a 45 percent less risk of dying. The mortality risk was 40 percent less for consistent beta blockers use and 42 percent less for the combination therapy.
"While the progress during that time has been steady, compliance is still not where it should be," Newby continued. "We found in our analysis a strong association between consistent long-term use and lower mortality. 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."
Ironically, the higher risk patients who stand to benefit the most from aspirin and beta blocker therapy were the least likely to be taking aspirin and/or beta blockers.
"Increasing age, diabetes, heart failure and smoking were associated with a lower likelihood of consistent use of each agent and their combination, while more recent entry into the DDCD, receiving a revascularization procedure or use of other evidence-based medicine predicted higher usage," Newby said.
The solution to improving the rates of aspirin and beta blockers should involve behavioral changes for both physicians and patients, Newby said.
"There are still doctors who are reluctant to prescribe these drugs to their patients, maybe not realizing that potential side effects are far outweighed by the benefits," she said. "It also should be second nature for physicians to see if certain of their patients should be taking these drugs after discharge."
The researchers plan further studies to determine the factors that lead patients to discontinue the medications. For aspirin and beta blockers, which have been on the market for decades and are relatively inexpensive, Newby doesn't believe that cost is a major factor.
"Part of the problem may be that patients don't realize, or are not told, that these agents need to be taken on a long-term basis," she said. "Finding the solution to these issues is the highest hurdle we face, but it's the one that when solved can make the biggest impact on outcomes."
Duke is planning other efforts to better understand the issues surrounding long-term patient compliance with evidence-based medicines, including a pilot project that will link Duke cardiologists and pharmacists with physicians and pharmacists in the community.
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 (AHQR), in consultation with the U.S. Food and Drug Administration (FDA). Duke is the coordinating center for the cardiovascular CERTs.
Other members of the Duke team were Nancy Allen-LaPointe, Pharm.D., Judith Kramer, M.D., Anita Chen, Bradley Hammill, Lawrence Muhlbaier, Ph.D., Elizabeth DeLong, Ph.D., and Robert Califf, M.D.