Stanford research shows medications underused in treating heart disease
STANFORD, Calif. Past studies have shown that various medications including beta blockers and aspirin can help manage heart disease. Yet a new study from Stanford University Medical Center indicates physicians continue to underprescribe these key treatments.
The study, conducted by Randall Stafford, MD, PhD, appears in the Jan. 1 issue of the Journal of the American College of Cardiology. It focuses on the outpatient use of the drug warfarin for atrial fibrillation (or irregular heartbeat), beta blockers and aspirin for coronary artery disease, and ACE inhibitors for congestive heart failure - all medications that have been shown to benefit patients in past clinical trials and population studies.
'There is no dispute over the benefit of these medications,' said Stafford, an assistant professor of medicine at the School of Medicine and at Stanford's Center for Research in Disease Prevention. 'The medications lead to a reduction in complications and a delay in progression of disease.'
Stafford and co-author David Radley at Yale University analyzed data over a 13-year period from two national surveys - the National Disease and Therapeutic Index and the National Ambulatory Medical Care Surveys. They examined more than 15,000 outpatient visits for irregular heartbeats and 30,000 outpatient visits each for coronary artery disease and congestive heart failure to determine the usage level of each class of medication.
'There is debate over the optimal usage level of each medication - and clearly the number is less than 100 percent,' said Stafford. 'But the level of use for each should be above 50 percent and probably closer to 80.'
What the researchers found in the data were usage levels well below the recommended levels. The data also showed that prescription rates rose during the 1990s - closely following many studies published in the 1980s showing the benefits of these medications. Increases in usage levels for several medications, however, slowed in later years. More specifically, the National Disease and Therapeutic Index data indicated:
Warfarin use for irregular heartbeat increased from 12 percent in 1990 to 41 percent in 1995, and then to 58 percent in 2002.
Beta blocker use for coronary artery disease increased slowly, from 19 percent in 1990 to 20 percent in 1995, and then to 40 percent in 2002.
Aspirin use for coronary artery disease increased slowly, from 18 percent in 1990 to 19 percent in 1995, and then to 38 percent in 2002.
Use of ACE inhibitors (including the newer angiotensin receptor blocker) for congestive heart failure increased from 24 percent in 1990 to 36 percent in 1996, and then to 39 percent in 2002.
'Both datasets demonstrate continuing underutilization of these cardiac medications of proven benefit,' said Stafford, adding that the only difference between the two surveys involved aspirin use, which was lower in the National Ambulatory Medical Care Surveys data. 'Adoption of these therapies has been slow to even approach acceptable levels.'
Stafford said a variety of factors contribute to these medications being underused. Among them are physicians' overemphasis on contraindications. 'Physicians are taught to do no harm and may withhold therapy that actually has more benefits than risks,' he said, adding that the U.S. health-care system doesn't easily facilitate the use of medication over the long term and emphasizes acute over preventive care.
'Physicians tend to focus on problems that patients come in the office with,' said Stafford. 'Very few patients come in and say to their doctor, 'You need to prevent a certain disease.''
Stafford said studies published in the mid-1990s arrived at similar conclusions and this latest study 'is a warning that what we've done over the past five to seven years (to correct this) has not been successful.' He said the study results call for improved education, an evaluation of quality-improvement practices in health care and perhaps more patient involvement. 'This suggests that patients may need to be their own advocates and make sure that these medications are a topic of conversation with their physicians,' he said.
Stafford did warn that the study has limitations. He said the surveys may not have accurately captured all medication use - physicians, for example, do not always report when patients are taking over-the-counter aspirin. The databases also may not always reveal whether doctors are not prescribing certain medications because of strong contraindications for particular patients.
Stanford Medicine integrates research, medical education and health care at its three institutions - Stanford University School of Medicine, Stanford Health Care (formerly Stanford Hospital & Clinics), and Lucile Packard Children's Hospital Stanford. For more information, please visit the Office of Communication & Public Affairs site at http://mednews.stanford.edu.