title: [Creative mathematics with clopidogrel; exaggeration of the preventive effect by manufacturer].
abstract: A number of Dutch medical journals recently carried an advertisement stating that clopidogrel treatment reduced the number of ischaemic complications with 26%, compared with aspirin treatment. This is a miscalculation: the actual reduction is 0.51% in absolute rates, and 8.7% in relative terms. The error by Sanofi-Synthelabo arose by comparison of the event rates for clopidogrel (5.32%) as well as for aspirin (5.83%) with that in an imaginary placebo group (7.77%), yielding a reduction of ischaemic complications of 2.45% and 1.94% respectively; erroneous comparison of these two numbers leads to a difference of 26%.
authors.affiliation: Academisch Ziekenhuis, Julius Centrum voor Patiëntgebonden Onderzoek, Utrecht.
authors.forename: A
authors.initials: A
authors.lastname: Algra
authors.forename: J
authors.initials: J
authors.lastname: van Gijn
authors.forename: L J
authors.initials: LJ
authors.lastname: Kappelle
authors.forename: P J
authors.initials: PJ
authors.lastname: Koudstaal
authors.forename: J
authors.initials: J
authors.lastname: Stam
authors.forename: M
authors.initials: M
authors.lastname: Vermeulen
mesh_terms: D000329:Advertising; D000077144:Clopidogrel; D003627:Data Interpretation, Statistical; D004345:Drug Industry / Q000379:methods*; D006801:Humans; D009203:Myocardial Infarction / Q000517:prevention & control; D009426:Netherlands; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use*; D016032:Randomized Controlled Trials as Topic / Q000706:statistics & numerical data; D020521:Stroke / Q000517:prevention & control; D013988:Ticlopidine / Q000031:analogs & derivatives* / Q000627:therapeutic use
chemical_list: D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine