Impact of single or multicentre study design on the results of trials examining the efficacy of adjunctive devices to prevent distal embolisation during acute myocardial infarction

Aims: We investigated using meta-analytic techniques, whether, and to what degree, single or multicentre study design affects clinical outcomes in randomised controlled trials examining the efficacy of adjunctive devices to prevent distal embolisation during acute myocardial infarction (AMI). Methods and results: We searched electronic databases, conference proceedings, and internet-based sources of information to identify relevant studies through March 2009. The pooled summary effect was estimated with a random effects model. Subgroup and meta-regression analyses were conducted to examine the impact of single or multicentre design on trial outcomes compared with other variables. A total of 25 randomised trials (5,919 patients) were included in the analysis. The major sources of heterogeneity in trial outcomes were single or multicentre design, type of device used, study size, study region, and presence of conflicts of interest, of which the most influential source of heterogeneity was single or multicentre design (p-values of regression coefficient on meta-regression analyses were 0.09 for mortality, 0.001 for incomplete ST-segment resolution, and 0.07 for impaired myocardial blush grade, respectively). . Conclusions: Single or multicentre study design has a significant impact on outcomes in trials examining the efficacy of adjunctive devices in AMI.