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Do randomized clinical trials with inadequate blinding report enhanced placebo effects for intervention groups and nocebo effects for placebo groups? A protocol for a meta-epidemiological study of PDE-5 inhibitors.
Syst Rev 2012; 1:54SR

Abstract

METHODS/DESIGN

We will quantify the magnitude of expectancy by comparing the effect estimates of trials with inadequate and adequate blinding. Blinding will be assessed using four domains from the Cochrane 'risk-of-bias' tool: allocation concealment; blinding of patient; caregiver; and outcome assessor. Our secondary aim is to identify factors that can modify expectations, such as prior experience with the intervention and drug side effects.We will perform an electronic search using a combination of controlled vocabulary and free text words in the following databases: MEDLINE, EMBASE, CENTRAL, and a clinical trials register. We will include randomized controlled trials, with either parallel or crossover design, that compare one phosphodiesterase-5 inhibitor with a placebo. The study's primary aim should be to investigate the efficacy of phosphodiesterase-5 inhibitors for treating male erectile dysfunction. Screening will take place at two levels: abstracts and titles, followed by full text reports. Two reviewers will independently extract data on the primary outcome and assess risk of bias.We will meta-analyze treatment effects, if appropriate, to assess the magnitude of enhanced placebo effects and nocebo effects in intervention and placebo groups, respectively. We will explore possible mediators of placebo and nocebo effects with subgroup and meta-regression analyses.

DISCUSSION

Treatments may confer significant costs and risk of adverse effects; it is important, therefore, to determine whether the effects of treatments are larger than expectancy alone. If treatment expectations can be used in a non-deceptive way to produce clinically advantageous outcomes, then it may be possible to incorporate such mechanisms into evidence-based healthcare decision-making.

Authors+Show Affiliations

Huisartsgeneeskunde, Vrije Universiteit Brussel, Brussel, Belgium. fredfeys@vub.ac.beNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

23151403

Citation

Feys, Frederik, et al. "Do Randomized Clinical Trials With Inadequate Blinding Report Enhanced Placebo Effects for Intervention Groups and Nocebo Effects for Placebo Groups? a Protocol for a Meta-epidemiological Study of PDE-5 Inhibitors." Systematic Reviews, vol. 1, 2012, p. 54.
Feys F, Bekkering GE, Singh K, et al. Do randomized clinical trials with inadequate blinding report enhanced placebo effects for intervention groups and nocebo effects for placebo groups? A protocol for a meta-epidemiological study of PDE-5 inhibitors. Syst Rev. 2012;1:54.
Feys, F., Bekkering, G. E., Singh, K., & Devroey, D. (2012). Do randomized clinical trials with inadequate blinding report enhanced placebo effects for intervention groups and nocebo effects for placebo groups? A protocol for a meta-epidemiological study of PDE-5 inhibitors. Systematic Reviews, 1, p. 54. doi:10.1186/2046-4053-1-54.
Feys F, et al. Do Randomized Clinical Trials With Inadequate Blinding Report Enhanced Placebo Effects for Intervention Groups and Nocebo Effects for Placebo Groups? a Protocol for a Meta-epidemiological Study of PDE-5 Inhibitors. Syst Rev. 2012 Nov 14;1:54. PubMed PMID: 23151403.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Do randomized clinical trials with inadequate blinding report enhanced placebo effects for intervention groups and nocebo effects for placebo groups? A protocol for a meta-epidemiological study of PDE-5 inhibitors. AU - Feys,Frederik, AU - Bekkering,Geertruida E, AU - Singh,Kavita, AU - Devroey,Dirk, Y1 - 2012/11/14/ PY - 2012/07/30/received PY - 2012/10/23/accepted PY - 2012/11/16/entrez PY - 2012/11/16/pubmed PY - 2012/11/16/medline SP - 54 EP - 54 JF - Systematic reviews JO - Syst Rev VL - 1 N2 - METHODS/DESIGN: We will quantify the magnitude of expectancy by comparing the effect estimates of trials with inadequate and adequate blinding. Blinding will be assessed using four domains from the Cochrane 'risk-of-bias' tool: allocation concealment; blinding of patient; caregiver; and outcome assessor. Our secondary aim is to identify factors that can modify expectations, such as prior experience with the intervention and drug side effects.We will perform an electronic search using a combination of controlled vocabulary and free text words in the following databases: MEDLINE, EMBASE, CENTRAL, and a clinical trials register. We will include randomized controlled trials, with either parallel or crossover design, that compare one phosphodiesterase-5 inhibitor with a placebo. The study's primary aim should be to investigate the efficacy of phosphodiesterase-5 inhibitors for treating male erectile dysfunction. Screening will take place at two levels: abstracts and titles, followed by full text reports. Two reviewers will independently extract data on the primary outcome and assess risk of bias.We will meta-analyze treatment effects, if appropriate, to assess the magnitude of enhanced placebo effects and nocebo effects in intervention and placebo groups, respectively. We will explore possible mediators of placebo and nocebo effects with subgroup and meta-regression analyses. DISCUSSION: Treatments may confer significant costs and risk of adverse effects; it is important, therefore, to determine whether the effects of treatments are larger than expectancy alone. If treatment expectations can be used in a non-deceptive way to produce clinically advantageous outcomes, then it may be possible to incorporate such mechanisms into evidence-based healthcare decision-making. SN - 2046-4053 UR - https://www.unboundmedicine.com/medline/citation/23151403/Do_randomized_clinical_trials_with_inadequate_blinding_report_enhanced_placebo_effects_for_intervention_groups_and_nocebo_effects_for_placebo_groups_A_protocol_for_a_meta_epidemiological_study_of_PDE_5_inhibitors_ L2 - https://systematicreviewsjournal.biomedcentral.com/articles/10.1186/2046-4053-1-54 DB - PRIME DP - Unbound Medicine ER -