title: Aspirin for the primary prevention of cardiovascular events: a systematic review and meta-analysis comparing patients with and without diabetes.
abstract: OBJECTIVE
  The negative results of two randomized controlled trials (RCTs) have challenged current guideline recommendations for using aspirin for primary prevention of cardiovascular events among patients with diabetes. We therefore sought to determine if the effect of aspirin for primary prevention of cardiovascular events and mortality differs between patients with and without diabetes.
  
  
  METHODS
  We conducted a systematic search of MEDLINE, EMBASE, Cochrane Library, Web of Science, and Scopus since their inceptions until November 2008 for RCTs of aspirin for primary prevention of cardiovascular events. Blinded pairs of reviewers evaluated studies and extracted data. Random-effects meta-analysis and Bayesian logistic regression were used to estimate the ratios of relative risks (RRs) of outcomes of interest among patients with and without diabetes. A 95% CI that crosses 1.00 indicates that the effect of aspirin does not differ between patients with and without diabetes.
  
  
  RESULTS
  Nine RCTs with moderate to high methodological quality contributed data to the analyses. The ratios of RRs comparing the benefit of aspirin among patients with diabetes compared with patients without diabetes for mortality, myocardial infarction, and ischemic stroke were 1.12 (95% CI 0.92-1.35), 1.19 (0.82-1.17), and 0.70 (0.25-1.97), respectively.
  
  
  CONCLUSIONS
  Whereas estimates of benefit among patients with diabetes remain imprecise, our analysis suggests that the relative benefit of aspirin is similar in patients with and without diabetes.
authors.affiliation: Mayo School of Graduate Medical Education, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Calvin
authors.forename: Niti R
authors.initials: NR
authors.lastname: Aggarwal
authors.forename: Mohammad Hassan
authors.initials: MH
authors.lastname: Murad
authors.forename: Qian
authors.initials: Q
authors.lastname: Shi
authors.forename: Mohamed B
authors.initials: MB
authors.lastname: Elamin
authors.forename: Jeffrey B
authors.initials: JB
authors.lastname: Geske
authors.forename: M Merce
authors.initials: MM
authors.lastname: Fernandez-Balsells
authors.forename: Felipe N
authors.initials: FN
authors.lastname: Albuquerque
authors.forename: Julianna F
authors.initials: JF
authors.lastname: Lampropulos
authors.forename: Patricia J
authors.initials: PJ
authors.lastname: Erwin
authors.forename: Steven A
authors.initials: SA
authors.lastname: Smith
authors.forename: Victor M
authors.initials: VM
authors.lastname: Montori
mesh_terms: D001241:Aspirin / Q000627:therapeutic use*; D002318:Cardiovascular Diseases / Q000517:prevention & control*; D003925:Diabetic Angiopathies / Q000517:prevention & control*; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use; D006801:Humans; D006973:Hypertension / Q000517:prevention & control; D008297:Male; D009203:Myocardial Infarction / Q000517:prevention & control; D015588:Observer Variation; D011322:Primary Prevention / Q000379:methods*; D016032:Randomized Controlled Trials as Topic; D020521:Stroke / Q000517:prevention & control
chemical_list: D005343:Fibrinolytic Agents; D001241:Aspirin