TUESDAY, April 20, 2010 (HealthDay News) -- One of six people who have stents implanted to keep an artery open ignore their doctor's orders to start taking the blood thinner Plavix immediately, and that ignorance nearly doubles their risk for a heart attack or death, new research finds.
The study, which involved 7,402 people who had the thin tubes put in after angioplasty, found that those most likely to benefit from the clot-preventing drug are most likely not to fill the prescription that is a standard part of the hospital discharge routine, said Dr. P. Michael Ho, an associate professor of medicine at the University of Colorado and lead author of a report published online April 20 in Circulation: Cardiovascular Quality and Outcome.
"Older patients are more likely to delay, and patients with previous heart attacks," said Ho, who is also a staff cardiologist at the Denver Veterans Affairs Health Center.
Prescriptions are almost always for clopidogrel (Plavix), the only blood thinner approved for use in the United States in 2004-2007, when the study was done. However, newer clot-preventing drugs are starting to be prescribed more often by U.S. doctors.
The study didn't look for reasons why 16.3 percent of the people who got stents implanted waited at least a day before filling their blood-thinner prescription. The median delay was three days, and 2.2 percent of those who got prescriptions never filled them.
But the study did record the hazards caused by that brief delay -- a 14.2 percent risk for heart attack or death in the next 22 months, compared with a 7.9 percent risk for those who acted promptly.
"Based on previous literature, it could be a lot of confusion about the hospital discharge process," Ho said. "They are given this laundry list of new medications, and they may not absorb all that information at once."
The actual incidence of delayed use of a blood thinner might be greater than that reported in the study, which used data on people enrolled in major integrated health systems, Ho said. "Outside such systems, there are more people with less insurance coverage and higher co-payments, so I suspect the rate might be higher," he noted.
Ho said the study has lessons not only for people who have stents implanted but for their medical caregivers, too.
"For clinicians and hospitals, it is important to look at the discharge process to make sure patients are getting appropriate discharge instructions, and also that they understand the importance of the medications they will be taking," he said. "We as clinicians should highlight the importance of each and every medication."
On the other end, "it is important for patients to ask questions so that they have a good idea of what medications are important to take," Ho said.
Dr. Rob Califf, vice president for clinical research at Duke University, said that it's "critical for doctors and health systems to do everything possible to be sure that people both fill their prescriptions and take their medicine."
One way to do that is to return to a once-common practice of sending someone out of the hospital with a few-day's supply of prescribed medications, said Dr. Stephen A. Siegel, an assistant clinical professor of medicine at New York University. Cost-cutting has eliminated that measure in many hospitals, but it helps ensure that the medication will be taken immediately and that a prescription for it will be filled, Siegel said.
The American Heart Association has more on stents.