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The Grading of Efficacy-Effectiveness in Clinical Trials (GEECT): a modified PRECIS tool.

Date and Location




Saturday 21 September 2013 - 10:30 - 12:00


Presenting author and contact person

Presenting author

Regina El Dib

Contact person

Regina El Dib
Abstract text
Background: When discussing treatment and talking about evidence, we refer to effectiveness (treatment that works under real-world conditions) and efficacy (treatment that works under ideal conditions). However, the use of these terms seems to be randomly chosen by the investigators who design clinical trials not reflecting the true purpose of the study. In addition, renowned educational institutions involved in Evidence-Based Medicine disseminate a very vague definition of these terms. The PRECIS tool was developed in 2009 with the aim of identifying the characteristics of clinical trials that distinguishes from pragmatic (effectiveness) and explanatory (efficacy) issues and to assist researchers in preparing their clinical trials. It is worthy to say that according to PRECIS, the classification of a clinical trial is not a dichotomy, i.e., there is a gradient between effectiveness and efficacy, therefore it is very difficult to conduct a clinical trial "purely" pragmatic or "purely" explanatory. However, it is unclear whether investigators when designing a clinical trial use PRECIS to help policy makers and health professionals to apply its results into their clinical practice. Objectives: To assess i) whether clinical trials published in high impact journals in the last 3 years used the criteria proposed by PRECIS to differentiate between effectiveness and efficacy and; ii) whether clinical trials´ authors have made appropriately use of the terms effectiveness and efficacy according to a new score (0 to 10) and classification (high or moderate efficacy, high or moderate effectiveness) proposed by us, called the Grading of Efficacy-Effectiveness in Clinical Trials (GEECT). Methods: A cross-sectional study of published randomized clinical trials from high impact journals mentioning the term effectiveness and/or efficacy was performed. We added to the PRECIS tool a score ranging from 0 (more efficacious) to 10 (more effective). Results: 842 randomized trials were analyzed by 19 investigators from different expertise areas. No clinical trials published in high impact journals in the last 3 years used the criteria proposed by PRECIS to differentiate between effectiveness and efficacy. The majority of the trials was classified as moderate effectiveness (51-75) and, they often did not matched the term chosen by their own clinical trials’ authors. Conclusions: The GEECT classification based on the 0 to 10 score system facilitated the identification of a clinical trial’s application related to real or ideal conditions, although the modified PRECIS tool is still highly subjective and can be easily misunderstood in their all domains according to each investigator’s own experiences, knowledge, and values. Furthermore, most clinical trials published in high impact journals in the last 3 years mistakenly use the terms effectiveness and efficiency, according to the GEECT tool, to illustrate the application of results in clinical practice making it difficult the development of health policies. More research are needed to establish the easiest and useful tool to a) facilitate the applicability of the results in clinical practice; b) distinguish between pragmatic (effectiveness) and explanatory (efficacy) results and; c) assist researchers in preparing and planning clinical trials. We also suggest that after the establishment of an ideal tool to determine the specific application of a clinical trial´s results (i.e., more about effectiveness or more efficacious), journals all over the world that publish clinical trials should request authors the submission of a quantitative score related to effectiveness or efficacy along with their full research article and, also publish a note with regards the effectiveness and efficacy scores to accompany the main text of a clinical trial.