Aspirin has long been the industry standard for the prevention and treatment of heart attacks. However, for the more than 20 million Americans living with diabetes, the standard dose of aspirin might not provide adequate protection against future heart attacks. Researchers have recently demonstrated that aspirin resistance is higher in diabetics with coronary artery disease (CAD) than in non-diabetics at the standard 81mg dose of aspirin.
Most CAD deaths are caused by platelets sticking together and forming blood clots (thrombosis) that block blood flow within arteries, resulting in a heart attack. Aspirin inhibits clotting by specifically blocking an important enzyme, COX-1, which keeps platelets from sticking together. However, some diabetic patients may require a higher aspirin dose to achieve sufficient COX-1 blockade.
"The occurrence of clotting in patients on aspirin therapy is of major interest within the cardiovascular community. The effect of aspirin dosing in diabetic patients on the prevalence of aspirin resistance remains unclear," said Paul A. Gurbel, M.D., director of the Center for Thrombosis Research at Sinai Hospital of Baltimore and lead author on this study. "Our data suggest that there may be a higher risk of thrombosis in diabetic patients during low dose aspirin therapy."
The team at the Sinai Center for Thrombosis Research studied 120 aspirin treated patients (30 patients with diabetes) with stable coronary artery disease. Participants were randomly assigned to receive 81mg, 162mg, or 325mg of aspirin daily for four weeks each, for a total of 12 weeks. The response to aspirin was then tested by multiple laboratory methods. It was found that diabetic patients exhibited a higher prevalence of aspirin resistance than non-diabetic patients with 81mg of aspirin.
"The results of our findings may help to determine the best aspirin dose for diabetic patients, moving physicians away from the one-size-fits-all approach to aspirin therapy," said Gurbel.