Placebo-Controlled Clinical Trial
A Placebo-Controlled Clinical Trial is a controlled clinical trial that is a placebo-controlled experiment.
- AKA: Sham-Controlled Clinical Trial.
- Context:
- It can (typically) be designed in a way that one group of clinical trial participants receives the placebo (e.g. inactive substance, inactive treatment) the other receives the experimental treatment.
- It can range from being an Open-Label Placebo-Controlled Clinical Trial to being a Blinded Placebo-Controlled Clinical Trial.
- It can range from (typically) being a Randomized Placebo-Controlled Clinical Trial to being a Non-Randomized Placebo-Controlled Clinical Trial.
- …
- Example(s):
- Effects of Open-label vs Double-blind Treatment in IBS (NCT02802241) [1].
- Interaction Between Drug and Placebo Effect:Randomized Placebo Controlled Trials May Not be Accurate in Determining Drug Effect Size (NCT01501591) [2].
- NCT02872103: Placebo-controlled Trial of F-627 in Women With Breast Cancer Receiving Myelotoxic Chemotherapy,
- NCT00994110: Placebo Controlled Trial of SOM230 for the Reduction of Post-Pancreatectomy Fistula, Leak, and Abscess,
- NCT00865202: A Placebo Controlled Trial Of L-Tryptophan In Post-Operative Delirium,
- NCT01993823: Active Treatment-controlled Study of G238 Compared to Clotrimazole 1% Otic Solution in Patients With Otomycosis,
- …
- Counter-Example(s):
- See: Clinical Trial Design, Clinical Trial Protocol, Blinded Experiment, Placebo Effect, Treatment Group, Control Group, Nocebo Effect, Placebo Comparator Clinical Trial Arm, Clinical Trial Control Arm, Clinical Trial Experimental Arm.
References
2021a
- (Wikipedia, 2021) ⇒ https://en.wikipedia.org/wiki/Placebo-controlled_study Retrieved:2021-11-21.
- Placebo-controlled studies are a way of testing a medical therapy in which, in addition to a group of subjects that receives the treatment to be evaluated, a separate control group receives a sham “placebo” treatment which is specifically designed to have no real effect. Placebos are most commonly used in blinded trials, where subjects do not know whether they are receiving real or placebo treatment. Often, there is also a further "natural history" group that does not receive any treatment at all.
The purpose of the placebo group is to account for the placebo effect, that is, effects from treatment that do not depend on the treatment itself. Such factors include knowing one is receiving a treatment, attention from health care professionals, and the expectations of a treatment's effectiveness by those running the research study. Without a placebo group to compare against, it is not possible to know whether the treatment itself had any effect.
Patients frequently show improvement even when given a sham or "fake" treatment. Such intentionally inert placebo treatments can take many forms, such as a pill containing only sugar, a surgery where nothing efficacious is actually done (just an incision and sometimes some minor touching or handling of the underlying structures), or a medical device (such as an ultrasound machine) that is not actually turned on. Also, due to the body's natural healing ability and statistical effects such as regression to the mean, many patients will get better even when given no treatment at all. Thus, the relevant question when assessing a treatment is not "does the treatment work?" but "does the treatment work better than a placebo treatment, or no treatment at all?" As one early clinical trial researcher wrote, "the first object of a therapeutic trial is to discover whether the patients who receive the treatment under investigation are cured more rapidly, more completely or more frequently, than they would have been without it." More broadly, the aim of a clinical trial is to determine what treatments, delivered in what circumstances, to which patients, in what conditions, are the most effective. Therefore, the use of placebos is a standard control component of most clinical trials, which attempt to make some sort of quantitative assessment of the efficacy of medicinal drugs or treatments. Such a test or clinical trial is called a placebo-controlled study, and its control is of the negative type. A study whose control is a previously tested treatment, rather than no treatment, is called a positive-control study, because its control is of the positive type. Government regulatory agencies approve new drugs only after tests establish not only that patients respond to them, but also that their effect is greater than that of a placebo (by way of affecting more patients, by affecting responders more strongly, or both). This close association of placebo effects with RCTs has a profound impact on how placebo effects are understood and valued in the scientific community.
- Placebo-controlled studies are a way of testing a medical therapy in which, in addition to a group of subjects that receives the treatment to be evaluated, a separate control group receives a sham “placebo” treatment which is specifically designed to have no real effect. Placebos are most commonly used in blinded trials, where subjects do not know whether they are receiving real or placebo treatment. Often, there is also a further "natural history" group that does not receive any treatment at all.
2021b
- (NIA/NIH) ⇒ https://www.nia.nih.gov/research/dgcg/nia-glossary-clinical-research-terms Retrieved:2021-11-21.
- QUOTE: Placebo Controlled Study – A method of investigation in which an inactive substance/treatment (the placebo) is given to one group of participants, while the test article is given to another group. The results obtained in the two groups are then compared to see if the investigational treatment is more effective in treating the condition.
2021c
- (MedicineNet, 2021) ⇒ https://www.medicinenet.com/placebo-controlled/definition.htm Retrieved:2021-11-21.
- QUOTE: Placebo-controlled: A term used to describe a method of research in which an inactive substance (a placebo) is given to one group of participants, while the treatment (usually a drug or vaccine) being tested is given to another group. The results obtained in the two groups are then compared to see if the investigational treatment is more effective than the placebo.
2021d
- (HIV, 2021) ⇒ https://clinicalinfo.hiv.gov/en/glossary/placebo-controlled-trial Retrieved:2021-11-21.
- QUOTE: Placebo-Controlled Trial: A type of clinical trial. In placebo-controlled trials, one group of participants (the control arm) receives an inactive drug (or other intervention), called a placebo, while another group of participants (the experimental arm) receives the active drug being tested. The two groups are compared to see if the drug is more effective than the placebo.
2020
- (Duarte et al., 2020) ⇒ Rui V. Duarte, Ewan McNicol, Luana Colloca, Rod S. Taylor, Richard B. North, and Sam Eldabe (2020). "Randomized Placebo‐/Sham‐Controlled Trials of Spinal Cord Stimulation: A Systematic Review and Methodological Appraisal". In: Neuromodulation, 23(1):10-18. DOI:https://dx.doi.org/10.1111/ner.13018.
2017
- (Ballou et al., 2017) ⇒ Sarah Ballou, Ted J. Kaptchuk, William Hirsch, Judy Nee, Johanna Iturrino, Kathryn T. Hall, John M. Kelley, Vivian Cheng, Irving Kirsch, Eric Jacobson, Lisa Conboy, Anthony Lembo, and Roger B. Davis (2017). "Open-Label Versus Double-Blind Placebo Treatment In Irritable Bowel Syndrome: Study Protocol For A Randomized Controlled Trial". In: BMC - Trials volume 18, Article number: 234 (2017).
- QUOTE: Although placebo is widely used in clinical and research settings, until recently it has always been administered “concealed” in the context of double-blind randomized controlled trials (RCTs) where patients are aware of the likelihood that the prescribed treatment may or may not contain an active ingredient or may be presented in an ethically dubious deceptive manner in which patients are unaware that the prescribed pills contain either an inactive ingredient or an active substance that had no effect on their condition. Here, we will briefly review the academic literature on the traditional use of blinded placebos, discuss recent research using open-label placebo (OLP), and describe the methodology and rationale for our current RCT, which was designed to compare open-label and double-blind placebo (DBP) in a sample of participants with irritable bowel syndrome (IBS).
2000
- (Ellenberg & Temple, 2000) ⇒ Susan S. Ellenberg, and Robert Temple (2000). "Placebo-controlled trials and active-control trials in the evaluation of new treatments. Part 1: ethical and scientific issues". In: Annals of internal medicine, 133(6):455-463. [https://doi.org/10.7326/0003-4819-133-6-200009190-00015 DOI:10.7326/0003-4819-133-6-200009190-00015.