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  1. Mega-trials and management of acute myocardial infarction.

    Article - En anglais

    Clinical management of acute myocardial infarction has been strongly influenced by large, simple trials (mega-trials) with unrestrictive protocols and limited data collection.

    The design has been adopted to increase statistical power to a maximum.

    Its validity rests on an effective randomisation procedure and intention-to-treat analysis of deaths.

    Experience has shown that mega-trials tend to generate effect-estimates nearer the null than those from conventional trials or meta-analyses.

    When a small or absent observed treatment effect (or subgroup effect) in a mega-trial contrasts with the results of conventionally designed trials, it is necessary to assess both null bias and failure to increase the true treatment effect to a maximum in the mega-trial.

    Null bias will arise when the contrast between treatment and no-treatment, or between subgroups, is blunted either by non-protocol therapy or by inaccuracy of data, including misclassification between subgroups.

    Each is more likely with an unrestrictive design.

    To increase the true treatment effect to a maximum, trial conditions must be specified with insight into mechanism, dose-dependence, and time-dependence.

    The mega-trial design is therefore unsuited to an exploratory role.

    These issues are illustrated by the examples of nitrates, angiotensin-converting-enzyme inhibitors, and magnesium in acute myocardial infarction but have general relevance to the validity and generalisability of simple trials.

    Mots-clés Pascal : Appareil circulatoire pathologie, Cardiopathie coronaire, Traitement, Homme, Infarctus, Myocarde, Essai thérapeutique contrôlé, Méthodologie, Royaume Uni, Europe, Myocarde pathologie

    Mots-clés Pascal anglais : Cardiovascular disease, Coronary heart disease, Treatment, Human, Infarct, Myocardium, Controlled therapeutic trial, Methodology, United Kingdom, Europe, Myocardial disease

    Logo du centre Notice produite par :
    Inist-CNRS - Institut de l'Information Scientifique et Technique

    Cote : 95-0516430

    Code Inist : 002B12A03. Création : 01/03/1996.