Placebo response and effect in randomized clinical trials: meta-research with focus on contextual effects.

ABSTRACT:

Background

Contextual effects (i.e., placebo response) refer to all health changes resulting from administering an apparently inactive treatment. In a randomized clinical trial (RCT), the overall treatment effect (i.e., the post-treatment effect in the intervention group) can be regarded as the true effect of the intervention plus the impact of contextual effects. This meta-research was conducted to examine the average proportion of the overall treatment effect attributable to contextual effects in RCTs across clinical conditions and treatments and explore whether it varies with trial contextual factors.

Methods

Data was extracted from trials included in the main meta-analysis from the latest update of the Cochrane review on "Placebo interventions for all clinical conditions

SUBMITTER: Hafliðadottir SH 

PROVIDER: S-EPMC8314506 | biostudies-literature | 2021 Jul

REPOSITORIES: biostudies-literature