ArticlePloS one2012
Informed consent and placebo effects: a content analysis of information leaflets to identify what clinical trial participants are told about placebos.
Article in PloS one, 2012. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT04182295 (Effect of Information on Placebo in the Informed Consent on the Trial Outcomes and Participant Blinding), which is not on this map. Cited by 21 papers, 1 of them a synthesis that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Effect of Information on Placebo in the Informed Consent on the Trial Outcomes and Participant Blinding
Who cites it
21 citing papers in PubMed, 1 synthesis or guideline pooled it, 34 citations in OpenAlex.
- Pooled it
- Anti-obesity effect of Neoagaro-oligosaccharides with overweight and obese subjects: a 16-week, randomized, double-blind, placebo-controlled clinical trial.BMC complementary medicine and therapies · 2023Trial
- Informing Adults With Back Pain About Placebo Effects: Randomized Controlled Evaluation of a New Website With Potential to Improve Informed Consent in Clinical Research.Journal of medical Internet research · 2019Trial
- Altruism, personal benefit, and anxieties: a phenomenological study of healthy volunteers' experiences in a placebo-controlled trial of duloxetine.Human psychopharmacology · 2016Trial
- Reporting quality of sham needles used as controls in acupuncture trials: a methodological evaluation.Chinese medicine · 2022Article
- Factors Underlying Patient and Surgeon Willingness to Participate in a Placebo Surgery Controlled trial: A Qualitative Investigation.Annals of surgery open : perspectives of surgical history, education, and clinical approaches · 2021Article
- Placebo comparator group selection and use in surgical trials: the ASPIRE project including expert workshop.Health technology assessment (Winchester, England) · 2021Article
- Article
- Review
- Does different information disclosure on placebo control affect blinding and trial outcomes? A case study of participant information leaflets of randomized placebo-controlled trials of acupuncture.BMC medical research methodology · 2018Article
- What trial participants need to be told about placebo effects to give informed consent: a survey to establish existing knowledge among patients with back pain.Journal of medical ethics · 2017Article
- Informed consent and clinical trials: where is the placebo effect?BMJ (Clinical research ed.) · 2017Article
- Informing Patients About Placebo Effects: Using Evidence, Theory, and Qualitative Methods to Develop a New Website.JMIR research protocols · 2016Article
- Article
- Placebo-controlled trials in pediatrics and the child's best interest.Italian journal of pediatrics · 2015Article
- Placebo-controlled clinical trials: how trial documents justify the use of randomisation and placebo.BMC medical ethics · 2015Article
- Stem cell trials for cardiovascular medicine: ethical rationale.Tissue engineering. Part A · 2014Article
- Article
- The potential benefit of the placebo effect in sham-controlled trials: implications for risk-benefit assessments and informed consent.Journal of medical ethics · 2013Article
- Placebo Use in Medicine: Use, Abuse & Therapy.Missouri medicineArticle
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
4 authors at 3 institutions in 2 countries.
Funding
Abstract
backgroundPlacebo groups are used in randomised clinical trials (RCTs) to control for placebo effects, which can be large. Participants in trials can misunderstand written information particularly regarding technical aspects of trial design such as randomisation; the adequacy of written information about placebos has not been explored. We aimed to identify what participants in major RCTs in the UK are told about placebos and their effects. METHODS AND
findingsWe conducted a content analysis of 45 Participant Information Leaflets (PILs) using quantitative and qualitative methodologies. PILs were obtained from trials on a major registry of current UK clinical trials (the UKCRN database). Eligible leaflets were received from 44 non-commercial trials but only 1 commercial trial. The main limitation is the low response rate (13.5%), but characteristics of included trials were broadly representative of all non-commercial trials on the database. 84% of PILs were for trials with 50:50 randomisation ratios yet in almost every comparison the target treatments were prioritized over the placebos. Placebos were referred to significantly less frequently than target treatments (7 vs. 27 mentions, p<001) and were significantly less likely than target treatments to be described as triggering either beneficial effects (1 vs. 45, p<001) or adverse effects (4 vs. 39, p<001). 8 PILs (18%) explicitly stated that the placebo treatment was either undesirable or ineffective.
conclusionsPILs from recent high quality clinical trials emphasise the benefits and adverse effects of the target treatment, while largely ignoring the possible effects of the placebo. Thus they provide incomplete and at times inaccurate information about placebos. Trial participants should be more fully informed about the health changes that they might experience from a placebo. To do otherwise jeopardises informed consent and is inconsistent with not only the science of placebos but also the fundamental rationale underpinning placebo controlled trials.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.