The benefit of aspirin therapy in type 2 diabetes: what is the evidence?

Many clinical guidelines recommend aspirin therapy for the prevention of cardiovascular events in individuals with type 2 diabetes. However it is unclear whether the level of evidence in guidelines is derived from studies carried out among individuals with diabetes. Medline and Embase databases were searched to retrieve studies published since 1990, evaluating the effect of aspirin on cardiovascular outcomes in subjects with type 2 diabetes. Four studies corresponded to the inclusion criteria. The three clinical trials retrieved could not prove from a statistical point of view, the benefits of aspirin therapy for subjects with type 2 diabetes. Reduction in cardiac mortality was found only in one observational study. Consequently, these findings suggest that the clinical guidelines have based their recommendations upon the expected benefit previously observed in other high-risk populations. Given the lack of hard evidence and the different well-known platelet physiology encountered in patients with diabetes, use of aspirin as a standard treatment at the highest level of evidence in guidelines for subjects with type 2 diabetes should be revisited.