ABSTRACT
Detailed definitions of these endpoints were described in the protocol and a thorough system of verifying all potential endpoints was established.
The protocol provided for interim analyses with a possible first evaluation after 1 year of follow-up. After 1 year of study experience, the total number of myocardial infarctions and coronary deaths were well below the projected totals. Therefore, the code was not broken and interim statistical analysis was not performed. The first code break occurred in June 1985 when all study participants had completed 3 years of follow-up (two-thirds of the population had completed 4 years, due to staggered entry).
