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Review
. 2011;13(2):217-24.
doi: 10.31887/DCNS.2011.13.2/npatsopoulos.

A pragmatic view on pragmatic trials

Nikolaos A Patsopoulos  1
Affiliations
Review

A pragmatic view on pragmatic trials

Nikolaos A Patsopoulos. Dialogues Clin Neurosci. 2011.

Abstract
in English, Spanish, French

Clinical trials have been the main tool used by the health sciences community to test and evaluate interventions, Trials can fall into two broad categories: pragmatic and explanatory. Pragmatic trials are designed to evaluate the effectiveness of interventions in real-life routine practice conditions, whereas explanatory trials aim to test whether an intervention works under optimal situations. Pragmatic trials produce results that can be generalized and applied in routine practice settings. Since most results from exploratory trials fail to be broadly generalizable, the "pragmatic design" has gained momentum. This review describes the concept of pragmatism, and explains in particular that there is a continuum between pragmatic and explanatory trials, rather than a dichotomy. Special focus is put on the limitations of the pragmatic trials, while recognizing the importance for and impact of this design on medical practice.

Los ensayos clínicos han sido la principal herramienta empleada por la comunidad de las ciencias de la salud para probar y evaluar las intervenciones. Los ensayos se pueden clasificar en dos grandes categorías: pragmáticos y explicatívos. Los ensayos pragmáticos están diseñados para evaluar la eficacia de las intervenciones en situaciones de la práctica rutinaria en la vida real, mientras que los ensayos explicativos tienen como objetivo probar si una intervención funciona en situaciones óptimas. Los ensayos pragmáticos generan resultados que pueden ser generalizables y aplicables en ambientes de la práctica habitual. Dado que la mayor parte de los resultados de los ensayos explicativos han dejado de ser amplíamente generalizables, el “diseño pragmático” ha cobrado fuerza. Esta revisión describe el concepto de pragmatismo y explica, en particular, que más que una dicotomía hay un continuo entre los ensayos pragmáticos y los explicatívos. Se pone especíal atención a las limitaciones de los ensayos pragmáticos, a la vez que se reconoce la importancia y el impacto de este diseño en la práctica médica.

Les études cliniques ont été le principal outil utilisé dans la communauté scientifique médicale pour tester et évaluer les traitements. Les études se répartissent en deux grandes catégories: les études pragmatiques et les études explicatives. Les études pragmatiques sont conçues pour évaluer l'efficacité des traitements dans des conditions de pratique quotidienne de la vie réelle, alors que les études explicatives ont pour but de tester un traitement en conditions optimales. Les études pragmatiques fournissent des résultats qui peuvent être généralisés et appliqués en pratique quotidienne, ce qui n'est pas le cas pour la plupart des études explicatives, et le «schéma pragmatique» a donc le vent en poupe. Cet article décrit le concept de pragmatisme et explique en particulier qu'il existe un continuum entre les études pragmatiques et explicatives, plutôt qu'une dichotomie, il est porté un regard particulier sur les limites des études pragmatiques, tout en reconnaissant leur importance et leur impact sur la pratique médicale.

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Figures

Figure 1.
Figure 1.. Schematic of the relationship between explanatory and pragmatic trials. The wide base of the pyramid depicts the relatively higher proportion of explanatory trials.
Figure 2.
Figure 2.. Articles per year catalogued in MEDLINE that have in the title or abstract the words pragmatic or naturalistic and the word trial. The red line represents the articles that are tagged from Medline as “Clinical Trial” or “Randomized Controlled Trial”. The exact search was “pragmatic* [tiab] OR naturalistic* [tiab]) AND trial” and was performed on May 5th 2011.
Figure 3.
Figure 3.. Interventional trials in the ClinicalTrials.gov registry. A. Trials using the words “pragmatic” and/or “naturalistic” and which claim to be interventional (n=111). B. Number of trials among the 111 presented in panel A that are tagged as “Open” (still recruiting, ongoing or not closed yet, n=47). C. Trials in the ClinicalTrials.gov registry that claim to be interventional and are tagged as “Open” (n=28 882). The search was performed on May 5th 2011 using the terms “pragmatic* OR naturalistic*.” Colors indicate the intensity of studies in majorworld regions. Counts give the exact number of studies per region.
See this image and copyright information in PMC

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