Explanatory Versus Pragmatic Approach in Controlled Clinical Trials, with Special References to Clinical Trials of Platelet-Active Drugs
A comparative trial may be undertaken with more than one aim in view. One type of objective is to ascertain whether a new treatment actually possesses the favourable activity in man which laboratory studies have led to expect. This is typical of the situation with a new drug or a new use for an old drug. In this case, the clinical trial, motivated by the same research-orientated attitude that the laboratory experimentation, requires the “top” conditions. Another type of objective is to assess the practical value of a new treatment in relation to other treatments: in this case, the advantages and drawbacks of the various possible treatments have to be taken into account with a view to making a recommendation for clinical practice. The trial is aimed at providing practising clinicians with a basis for decisions concerning the choice of therapy, and its motivation is strictly practical in nature. Finally, the explanatory or pragmatic problem formulation is determining for the choice of treatment, of patients, of criteria and of methods of comparison. The clinical trials of platelet-active drugs in coronary and cerebro-vascular diseases, started and completed in the last ten years, are discussed on basis of these two different approaches. Their aim was to demonstrate the efficacy of these drugs and all had an explanatory design. However, for most of them, the choice of purely pragmatic criteria for assessing outcome could explain the questionable and unsatisfying conclusions to which they ended. These examples show the necessity of an unambiguous formulation and a corresponding design of the tria.They underline the importance of strategy in the choice and the priorities of different trials.
Unable to display preview. Download preview PDF.
- Anonymous (1980). Aspirin after myocardial infarction. The Lancet, I, 1172–1173.Google Scholar
- Bredin, K. (1977). Multicenter two-year prospective study on the prevention of secondary myocardial infarction by ASA in comparison with phenprocoumon and placebo. In Multicenter Controlled Trials: Principles and problems, edited by Boissel JP, Klimt CR, Paris, INSERM, 76, 79–92Google Scholar
- Boissel, JP., Leizorovicz, A., Schbath, J., Destors, J.M., Gillet, J. (1981). EPSIM, the French oral anticoagulant-aspirin trial in post-myocardial infarction patients: design, organization and quality control procedures. The Scandinavian Journal of Haematology, 27, sup. 38, 47–70.Google Scholar
- Elwood, P.C., Sweetnam, P.M., (1979). Aspirin and secondary mortality after myocardial infarction. The Lancet, II, 1313–1315.Google Scholar
- Furberg, C.D., May, G.S. (1980). Clinical trials of platelet active drugs in coronary heart disease: summary of design features. Circulation 62, sup. V: V 49–V 52.Google Scholar
- Kakkar, V.V., Corrigan, T.P., Fossard, D.P., Sutherland, I. (1975). Prevention of fatal postoperative pulmonary embolism by low doses of heparin. The Lancet, II, 45–51.Google Scholar
- Packham, M.A., Mustard, J.F. (1980). Pharmacology of platelet-affecting drugs. Circulation, 62, (sup. V), V 41–V 41.Google Scholar
- Passamani, E.R. (1980). Summary of on-going clinical trials of platelet-active drugs in cardiovascular disease. Circulation, 62 (sup. V), V 106– V 110.Google Scholar
- Samama, M., Devred, C., Bousser, M.G. (1976). Etude critique des essais thérapeutiques consacrés à l’héparine à faibles doses et aux antiagrégants plaquettaires. La Revue de Médecine, 21–22, 1191–1200.Google Scholar
- Schwartz, D., Flamant, R., Lellouch, J. (1980). Clinical Trials. Academic Press. London, New York, Toronto, Sidney, San Francisco.Google Scholar
- The Persantine Aspirin Reinfarction Study Research Group (1980). Persantine and Aspirin in coronary heart disease. Circulation, 62, 449–461.Google Scholar
- Weiss, H.J. (1980). Platelet-active drugs in the secondary Prevention of Cardiovascular Events. An overview. Circulation, 62 (sup. V), V 41–V 43.Google Scholar