title: Effect of β-blockers on platelet aggregation: a systematic review and meta-analysis.
abstract: OBJECTIVE
  Platelets play an important role in cardiovascular disease, and β-blockers are often prescribed for cardiovascular disease prevention. β-Blockers may directly affect platelet aggregation, because β-adrenergic receptors are present on platelets. There is uncertainty about the existence and magnitude of an effect of β-blockers on platelet aggregation. The aim of this study was to perform a systematic review and meta-analysis of the effect of β-blockers on platelet aggregation.
  
  
  METHODS
  MEDLINE and EMBASE were searched until April 2014. Two reviewers independently performed data extraction and risk of bias assessment. Type of β-blocker, population, treatment duration and platelet aggregation were extracted. Standardized mean differences were calculated for each study and pooled in a random-effects meta-analysis.
  
  
  RESULTS
  We retrieved 31 studies (28 clinical trials and three observational studies). β-Blockers decreased platelet aggregation (standardized mean difference -0.54, 95% confidence interval -0.85 to -0.24, P < 0.0001). This corresponds to a reduction of 13% (95% confidence interval 8-17%). Nonselective lipophilic β-blockers decreased platelet aggregation more than selective nonlipophilic β-blockers.
  
  
  CONCLUSIONS
  Clinically used β-blockers significantly reduce platelet aggregation. Nonselective lipophilic β-blockers seem to reduce platelet aggregation more effectively than selective nonlipophilic β-blockers. These findings may help to explain why some β-blockers are more effective than others in preventing cardiovascular disease.
authors.affiliation: Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Tobias N
authors.initials: TN
authors.lastname: Bonten
authors.forename: Chiara E I
authors.initials: CE
authors.lastname: Plaizier
authors.forename: Jaap-Jan D
authors.initials: JJ
authors.lastname: Snoep
authors.forename: Theo
authors.initials: T
authors.lastname: Stijnen
authors.forename: Olaf M
authors.initials: OM
authors.lastname: Dekkers
authors.forename: Johanna G
authors.initials: JG
authors.lastname: van der Bom
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000494:pharmacology* / Q000627:therapeutic use; D002318:Cardiovascular Diseases / Q000097:blood / Q000209:etiology / Q000517:prevention & control*; D002986:Clinical Trials as Topic; D006801:Humans; D064887:Observational Studies as Topic; D010974:Platelet Aggregation / Q000187:drug effects*
chemical_list: D000319:Adrenergic beta-Antagonists
keywords: meta-analysis; platelet aggregation; β-blockers
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