title: 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.
abstract: OBJECTIVE
  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).
  
  
  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.
authors.affiliation: Division of Cardiovascular Medicine, Oregon Health and Science University, Portland, OR, USA. yoichiinaba@yahoo.com
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Inaba
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Chen
authors.forename: Nisha
authors.initials: N
authors.lastname: Mehta
authors.forename: Steven R
authors.initials: SR
authors.lastname: Bergmann
mesh_terms: D000368:Aged; D015906:Angioplasty, Balloon, Coronary / Q000009:adverse effects* / Q000706:statistics & numerical data; D015982:Bias; D002983:Clinical Competence; D016265:Conflict of Interest; D004617:Embolism / Q000209:etiology / Q000517:prevention & control*; D004867:Equipment Design; D019317:Evidence-Based Medicine; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015337:Multicenter Studies as Topic; D009203:Myocardial Infarction / Q000628:therapy*; D016032:Randomized Controlled Trials as Topic; D012044:Regression Analysis; D015203:Reproducibility of Results; D012107:Research Design / Q000706:statistics & numerical data; D012111:Residence Characteristics; D018401:Sample Size; D013396:Suction / Q000295:instrumentation* / Q000706:statistics & numerical data; D017131:Thrombectomy / Q000295:instrumentation* / Q000706:statistics & numerical data; D016896:Treatment Outcome