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Placebo-Reviews

Two systematic reviews on the size of effects of different placebo interventions

Funding: BMBF, Förderkennzeichen 01KG0924

Duration: 1.11.2009 to 30.04.2011

Primary Investigator: 

PD Dr. Klaus Linde (Institut für Allgemeinmedizin, Orleansstr. 8, D-81667 München, TU München)

Project Members: 

Klaus Linde

Karin Meissner, München

Jos Kleijnen, York;

Asbjørn Hróbjartsson, Kopenhagen

Gerta Rücker

Gerd Antes (IMBI)

 

Objectives

Review 1: To investigate whether there is evidence from /direct/ comparisons in randomized clinical trials that some placebo or sham interventions are more effective than others. Review 2: To investigate whether there is evidence from /indirect/ comparisons of randomized clinical trials on the prophylaxis of migraine that some placebo or sham interventions are more effective than others.

 

Summary

Background: There is increasing evidence that physical or behavioural sham interventions might have more potent placebo effects than, for example, a drug placebo. This could have important implications for the interpretation of clinical trials and decision making. Objective: In the proposed project we will perform two reviews. In review 1 we will investigate whether there is evidence from direct comparisons in randomized clinical trials that some placebo or sham interventions are more effective than others. In review 2 we will investigate whether there is evidence from indirect comparisons of randomized clinical trials on the prophylaxis of migraine that some placebo or sham interventions are more effective than others. Methods: In review 1 we will only include randomized trials which include two different types of placebo interventions (for example, a drug placebo and sham biofeedback). As eligible trials will come from various medical fields findings will be summarized mainly in a descriptive manner, although we will try to perform exploratory quantitative analyses. In review 2 we will include placebo-/sham-controlled trials of any intervention for migraine prophylaxis reporting relevant outcomes (response and/or headache frequency). Pooled effect sizes (for pre-post changes in true treatment and placebo/sham groups as well as for between-group differences) for subgroups of trials using similar placebo or sham interventions will be calculated and compared in an exploratory manner.

 

Publications