ATT: Antithrombotic Trialists' Collaboration
200,000 high risk individuals
95,000 low-risk participants
The Antithrombotic Treatment Trialists’ (ATT) Collaboration was set up in the 1990s to conduct worldwide meta-analyses of randomised trials of anti-thrombotic therapy so as to provide reliable information about the benefits and hazards, among particular types of patients, of such therapy.
The ATT Collaboration has shown that, among patients at high risk of occlusive vascular events (ie, those with acute or previous vascular disease or some other predisposing condition), long-term anti-platelet therapy (eg, with aspirin) reduces the yearly risk of serious vascular events (non-fatal myocardial infarction, non-fatal stroke or vascular death) by about a quarter. However, in patients without previous vascular disease, aspirin is of uncertain net value as the reduction in vascular occlusive events needs to be weighed against the risk of any increase in major bleeds.
The current main focus of the Collaboration is to update its analyses to include data from trials of antiplatelet therapy that have reported since the time of the previous publications.