Execution time determines the outcome of the multicenter randomized controlled trials. 
Multicenter randomized controlled trials are the core of evidence-based medicine.  Our study aimed to investigate the key factor which determined the outcome of the multicenter randomized controlled trials.  We searched publications in PubMed for multicenter randomized controlled trials reporting primary data on treating and preventing cardiovascular diseases circulation area.  The data were extracted from the including trials and used for analysis.  A total of 1075 trials for treating and preventing cardiovascular diseases were included, of which 979 were involved in the heart diseases and 96 involved in stroke.  The execution time significantly contributed to the outcome of trials with shorter time related to significant outcome.  However, the numbers of participated centers and their locations and participants had no effect on the outcome of trials.  Moreover, the number of centers showed no significant relationship with execution time.  Execution time but not centers or participants contributed to the outcome of multicenter randomized controlled trials.