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DURHAM, N.C. – Despite substantial evidence that aspirin saves lives and reduces the risk of heart attacks, a study conducted by Duke University Medical Center researchers indicated that, as of 1999, one in five people with coronary artery disease still did not take aspirin regularly.
In the study, published in the March 15, 2002, issue of the American Journal of Cardiology, 80.5 percent of patients questioned used aspirin in 1999. The 25,049 patients involved in the study, who were pulled from the Duke Databank for Cardiovascular Disease and had coronary artery disease diagnosed by angiography at Duke, were questioned on their aspirin use between 1995 and 1999.
While the 80.5 percent figure was a substantial increase from the 59.2 percent of patients using aspirin in 1995, Robert Califf, M.D, the study's lead author, said the percentage seen in the 1999 data was "disappointingly low" considering the wealth of information supporting aspirin's benefits in addition to it being inexpensive and available without prescription.
"Given the strong evidence for the benefit of aspirin combined with its low cost, the failure to achieve greater than 95 percent use of aspirin, or other antithrombotic therapy in this population, is disappointing. Adherence should have been greater," said Califf, who is director of the Duke Clinical Research Institute. He and his colleagues plan further studies to continue to follow the trend in aspirin use after 1999, the latest year for which data were available.
The study also showed that coronary artery disease patients who never used aspirin had nearly twice the risk of death (risk ratio of 1.85) than those patients who used aspirin, Califf noted.
Men were more likely than women to be taking aspirin, according to the study results. Higher use also was seen among younger patients, nonsmokers and patients with a prior heart attack or who underwent revascularization, a procedure in which clogged coronary arteries were unblocked. Higher use also was recorded in patients seeing cardiologists for follow-up care and among patients whose physicians referred a large number of patients for coronary angiography at Duke.
Those patients who were less likely to be using aspirin therapy included those with heart failure, diabetes and hypertension. Califf especially urged patients with diabetes to consult their physicians concerning the use of aspirin; since previous research findings have emphasized the substantial benefits aspirin use can offer these patients.
"Too many patients without contraindications to aspirin fail to take it regularly. The health care system currently lacks effective methods to ensure that patients who have coronary artery disease have adequate follow-up concerning aspirin use," Califf said.
A small proportion of people should avoid aspirin use, Califf said. These include people with allergies to aspirin and with a history of significant gastrointestinal bleeding or gastrointestinal pain.
As recently as January 2002, the U.S. Preventative Services Task Force, part of the Public Health Service, strongly recommended that doctors discuss aspirin therapy with their patients, especially those at risk of coronary artery disease. These patients include men over the age of 40, postmenopausal women and younger people with risk factors for heart disease (smoking, diabetes, hypertension).
Every year, more than 1 million Americans die from heart attacks and other forms of coronary artery disease.
"Physicians and patients simply may forget this ubiquitously available treatment," Califf said, adding that further evaluation is needed on why patients fail to take aspirin. "There is an absence of mechanisms and systems to remind patients about the need to adhere to routine secondary prevention."
Califf said Duke soon will implement systems that will provide a safety net of reminders for patients regarding aspirin use. "This study was one of the things that helped prompted us to look into this," he said.
Califf noted that the number of patients using aspirin in this study might be higher than other populations because of the amount of data maintained by the Duke Databank for Cardiovascular Disease.
The study was conducted under the auspices of the Center for Education and Therapeutics (CERTs), a research program administered by the Agency for Healthcare Research and Quality (AHRQ) in consultation with the federal Food and Drug Administration to conduct research and provide education that will advance the optimal use of drugs, medical devices and biological products. The study was supported in part by a grant from the AHRQ.
Joining Califf in the study were Duke colleagues Elizabeth DeLong, Ph.D., Truls Ostbye, M.D., Lawrence Muhlbaier, Ph.D., Anita Chen, Bradley Hammill, Charles McCants, Judith Kramer, M.D., and Nancy LaPointe, PharmD.