That’s the message from researchers involved in the Survey of the Health of Wisconsin (SHOW), who studied aspirin use in 831 Wisconsinites.
“Our data showed that aspirin therapy is underused by people at risk for cardiovascular disease, who could be protected with regular use,” says Dr. Javier Nieto, Survey of the Health of Wisconsin director and senior author on the study. “But we found that aspirin is overused by people at low risk for CVD, and the danger here is that it may lead to major intestinal bleeding.”
The findings from this study, led by Dr. Jeffrey J. VanWormer of the Epidemiology Research Center at Marshfield Clinic Research Foundation and appearing in the September issue of The Journal of Family Practice, are based on a general population sample.
Low doses of aspirin protect the cardiovascular system by keeping platelets, cells that allow blood to clot, from clumping together and forming dangerous clots that could block blood flow to the heart or brain. On the flip side, the anti-clotting, blood-thinning qualities of aspirin can lead to bleeding, especially in the intestines.
Researchers found that of the 268 patients who could benefit from aspirin therapy according to national clinical guidelines, only 31 percent were using it regularly. Of the 563 participants who did not need to be on aspirin according to the guidelines, 18 percent were taking it regularly.
In the group that could benefit from aspirin therapy, participants who were older used aspirin more regularly than younger participants; and women had significantly higher odds of regular aspirin use than men.
Among those for whom aspirin therapy was not needed, the odds of using aspirin regularly were significantly higher among older participants versus younger participants, and significantly lower among Hispanic or non-white participants relative to non-Hispanic whites.
“This is the first study to use the most up-to-date clinical guidelines that identify which participants should or should not be taking daily aspirin for heart-disease prevention in the first place,” VanWormer said. “It provides a fairly solid picture of the subgroups of Wisconsin adults who are not taking full advantage of this preventive therapy, and where extra efforts might be needed.”
Previous studies have shown that, on average, about 1.3 major bleeding events occur per 1,000 person-years of regular aspirin use. “That would translate into an estimated 350 major bleeding events per year in Wisconsin that are attributable to aspirin overuse,” says Nieto, who also is chair of the Department of Population Health Sciences.
The researchers recommend that clinicians develop more effective programs to ensure that patients undergo regular screening for aspirin use, particularly middle-aged men at high risk for cardiovascular disease.
“Patient education may also be needed to better inform people, particularly older, non-Hispanic whites, about the risks of regular aspirin use that is not medically indicated,” Nieto says.
The Survey of the Health of Wisconsin is the first statewide research survey of its kind to measure information on critical health conditions in Wisconsin. It is modeled after the Center for Disease Control’s national survey, NHANES, which has provided key health information about the nation’s health for 35 years.
With a state focus, the Survey of the Health of Wisconsin provides a comprehensive picture of the health of Wisconsin residents, helping to identify needs and target resources where they are most needed.
In addition to Drs. VanWormer and Nieto, co-authors include Dr. Robert Greenlee of the Marshfield Clinic Research Foundation; and Dr. Patrick McBride, Dr. Paul Peppard, Dr. Kristen Malecki and Jianhong Che of the University of Wisconsin School of Medicine and Public Health.
University of Wisconsin School of Medicine and Public Health