LAUSR

The mainstay of acute coronary syndrome (ACS) management beyond reperfusion and symptoms control is focused on decreasing the incidence of cardiovascular (CV) events. Ongoing improvement in medical therapy and the introduction of an early invasive approach and revascularization for patients with ACS led to a decrease in adverse outcomes. The evidence that led to these improvements in clinical outcomes came from randomized controlled trials. Such trials however require an adequate number of events to have sufficient power. Therefore, there is a frequent need to increase the sample size of clinical trials involving patients with ACS. The use of composite endpoints in clinical trials serves several purposes: it allows reduction of the sample size and cost and thus renders trials more feasible to complete. It also allows simultaneous assessment of multiple important outcomes related to the same disease process and study intervention. However, there are also disadvantages to the use of composite outcomes that need to be considered. Treatment effects vary across different components, and each componentmay have a different clinical impact. Often, there is a lesser effect for the more important outcome. The most common and important endpoints used in CV trials are death and myocardial infarction (MI). Recognizing the importance of stroke, it has often also been included in recent years. Other outcomes such as heart failure, need for revascularization, and hospital admission are also often included. Sometimes, variables with an opposite treatment effect such as bleeding are included to combine safety and efficacy. Despite the effort to combine events with relatively similar effect, each carries a different prognosis and a different impact on a patient's quality of life or on the health care system. When data frommultiple trials are analyzed, there is an opportunity to explore and compare the effect on individual outcomes. In this issue of the journal, Hess et al have combined patient-level data from the 4 large recent ACS trials and report on the patient characteristics that predispose for