Anticoagulant therapy in acute myocardial infarction: Demonstration of a selection bias in a retrospective study

M. Ravid, Neal Kleiman, J. Shapira, M. Lischner, D. Feigl

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

Records of 851 patients with first acute myocardial infarction were analyzed in order to identify the effect of anticoagulant therapy on hospital mortality. A coronary prognostic index was applied and the patients were allocated into subgroups with similar predicted prognosis. When the mortality rates of treated versus non-treated patients were compared within each subgroup, no effect of anticoagulants on mortality could be demonstrated. However, when the patients were divided only according to anticoagulant therapy, a significantly lower mortality rate was found in the treated group: 12.3% versus 22.3% (p< 0.001). The disparity of results obtained via different methods of patient allocation may be explained by the existence of a selection bias expressed by the choice of better risk patients for anticoagulant treatment. Indeed, analysis of the records showed that the ratio of treated versus non-treated patients decreased in parallel with the worsening of prognosis.

Original languageEnglish (US)
Pages (from-to)753-757
Number of pages5
JournalThrombosis Research
Volume18
Issue number6
DOIs
StatePublished - Jun 15 1980

Keywords

  • Myocardial infarction
  • anticoagulants
  • prognostic index
  • selection bias

ASJC Scopus subject areas

  • Hematology

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