Protocol for a prospective collaborative overview of all current and planned randomized trials of cholesterol treatment regimens. Cholesterol Treatment Trialists' (CTT) Collaboration.

The Cholesterol Treatment Trialists' Collaboration aims to provide reliable information about the effects on mortality and morbidity of treatments that modify blood lipid levels for a wide range of patient populations and risk groups. This protocol prospectively defines study eligibility, the main questions to be addressed, and statistical methods to be used. Additionally, by establishing a register of ongoing and planned trials prior to any trial results being known, this systematic overview attempts to avoid the methodologic problems and potential data-dependency of a retrospective project. The collaboration expects to have individual patient data on > 60,000 subjects by the year 2000, including 12,000 women and 20,000 elderly subjects, and should have good power to examine any effects on non-coronary artery disease events. Overall, there should be about 1,900 non-coronary artery disease deaths and > 2,000 total cancer events.