Obesity and Altered Aspirin Pharmacology

Obesity is an independent risk factor for cardiovascular morbidity and mortality due to atherothrombotic events and represents a group of patients who are in need of optimized antithrombotic therapy. Central to the obesity-related risk of atherothrombosis is a pro-thrombotic state characterized by increased levels of coagulation factors, impaired fibrinolysis, and platelet hyper-reactivity, which results from the interaction among the features clustering in obesity: insulin resistance, inflammation, oxidative stress, and endothelial dysfunction. Aspirin is a cornerstone antiplatelet drug that has substantial interpatient variability in pharmacodynamic response and a number of reports have demonstrated that obesity is a risk factor for a reduced aspirin pharmacodynamic response. The inflammatory state associated with obesity, particularly a metabolic endotoxemia, may set in motion a number of mechanisms that increase platelet reactivity and platelet turnover and decrease aspirin bioavailability, all contributing to a poor aspirin response. A greater understanding of the mechanisms underlying obesity-related high on-aspirin platelet reactivity will help in optimization of antithrombotic therapy in this patient population.