The randomized controlled trial is an experimental clinical research protocol that compared a group called “intervention” testing a new therapy or new share of health prevention and a group called “review” in the (usual care) standard recommendations or taking a placebo (placebo). The assignment of participants in one group is randomly (draw). This choice can be made only with the knowledge of the participants (single-blind) and also without the knowledge of researchers and clinicians (double blind). By controlling all variables before and ensuring the homogeneity of the groups at the beginning of the study, only the action of the new therapy or new preventive health program may have played in explaining the differences obtained indicators measured. This type of protocol phase 3 formally establishes a causal relationship between innovation and tested the improvement observed. The randomized controlled trial thus produces the highest level of evidence of effectiveness of a new therapy or a new health prevention action according to the principles of Evidence Based Medicine.
Blog on Health refers to randomized controlled trials in the original study sections and review questions.
Observations to the evidence of effectiveness
Cohort studies and pilot studies (or feasibility) report benefits of therapeutic innovation or action on health prevention different indicators: health status, quality of life, direct costs, indirect costs of health equity social. Unfortunately, these observations do not make sufficient scientific and medical evidence (Craig et al., 2008). To obtain this evidence, any therapeutic innovation or health prevention should four steps. In the drug sector, these steps are rigorously standardized methodologically framed legally and ethically monitored (World Medical Association, 1997). Progress remains to be made of standardization in the field of non-drug interventions.
Clinical phases in the drug sector
Phase 1 is a study regarding healthy volunteers in which drug tolerance (limit of toxicity) and reactions in humans (minimum active dose kinetics of the drug, bioavailability) were tested.
Phase 2 is to administer the drug to patients for an initial assessment of the pharmacological efficacy, research therapeutic properties (dose / effect relationship, optimal dose, optimal administration).
Phase 3 is a comparative or randomized controlled clinical trial testing the properties of the new drug compared to placebo or an existing treatment (“standard treatment”). The new drug has to prove its efficacy and / or superiority compared to standard treatment.
Phase 4 is intended to pharmacovigilance, to detect rare or delayed adverse effects and adverse reaction reporting.
The general message
When an advertising message or other communication to a product announcement “proven”, it is not certain that the product in question has been the subject of a randomized controlled trial quality. Consumers can quickly be fooled about the virtues of this product on the health and quality of life. If the regulation of drugs is extremely accurate, some aspects still seem unresolved in the field of non-pharmacological interventions such as dietary supplements, medical devices, new technologies for health or arrangements living areas. LeBlog in Health aims to increase awareness of the clinical studies using the methodology of the randomized controlled trial and having passed all the verification steps leading medical and scientific journals.
What it means for Health Professionals
Irrefutable evidence of efficacy and health economics of many innovations in health and health prevention are not available because of the lack of randomized controlled trials of high power. Therefore, meta-analyzes remain cautious about the effects and emphasize their heterogeneity. Learned societies and health authorities remain dubious about their recommendation. Policymakers hinder their marketing and / or reimbursement. Ultimately, healthcare professionals and prevention are skeptical about their use. LeBlog in Health aims to increase awareness of the results of studies using the methodology of the randomized controlled trial and having passed all the verification steps leading medical and scientific journals.
What it means for Researchers
The number of randomized controlled trials is insufficient in the medical and scientific literature compared to mechanistic basic research. Some published studies often lack statistical power (Boutron et al., 2012), mainly because of inadequate number of subjects and increased quality requirements (Consolidated Standards of Reporting Trials). It must be said that these protocols intervention research are extremely costly in human financial, and material. They are as complex to develop because of difficult choices between a methodological ideal (but not later more reproducible in the “real life” of patients) and the local reality feasibility (but subject to bias questioning any demonstration). Randomized controlled trials are complicated to carry to term, that is to say, a publication in a scientific journal. An excellent summary for the establishment of a randomized controlled trial is available on the French website Institutes of Health Research Canada. Blog on Health aims to increase awareness of the clinical studies using the methodology of the randomized controlled trial and having passed all the verification steps leading medical and scientific journals.
What it means for Policymakers
Professionals, users and governments require scientific and medical evidence of the effectiveness of therapeutic innovations and prevention. The surveys or case studies reflecting the satisfaction of a handful of users results are not enough. In a context of delisting and charlatanism opportunistic, health is far too precious to be limited to particular experiences or recipes grandmother. Blog on Health aims to increase awareness of the clinical studies using the methodology of the randomized controlled trial and having passed all the verification steps leading medical and scientific journals.
Boutron I, Ravaud P, Moher D (2012). Randomized clinical trials of non pharmacological treatments. Boca Raton : CRC Press Taylor and Francis.
Craig P, Dieppe P, Macintyre S, Michie S, Nazareth I, Petticrew M (2008). Developing and evaluating complex interventions: the new Medical Research Council guidance. British Medical Journal, 337, 979-983.
World Medical Association (1997). Declaration of Helsinki. Recommendations guiding physicians in biomedical research involving human subjects. Journal of American Medical Association, 277, 925-926.
To reference this Blog en Sante © article.
Ninot G (2014). Definition of randomized controlled. Blog en Sante, L7.
© Copyright 2014 Grégory Ninot. All rights reserved.