A third of systematic reviews changed or did not specify the primary outcome: a PROSPERO register study

Ref ID 364
First Author A. C. Tricco
Journal JOURNAL OF CLINICAL EPIDEMIOLOGY
Year Of Publishing 2016
URL https://www.jclinepi.com/article/S0895-4356(16)30076-2/fulltext
Keywords • General medical
• Pre-specification
• Multiplicity
• Protocols
Problem(s) • Multiplicity of outcomes and lack of pre-specification for outcome reporting
Article Type Empirical
Article Subtype Cross-sectional survey/Methodological systematic review
First Author Country Canada
Aim To assess outcome reporting bias of published systematic reviews that were registered in PROSPERO up to November 2013 and to determine the likelihood of having a change in primary outcome when the meta-analysis result was favourable and statistically significant.
Level of Investigation Analytical
Summary of Findings A discrepancy in the primary outcome occurred in 32% of the included reviews and 39% of the reviews did not explicitly specify a primary outcome(s); 6% of the primary outcomes were omitted. There was no evidence of a significant increased risk of adding/upgrading or decreased risk of downgrading an outcome when the meta-analysis result was favourable and statistically significant. There was no evidence of significant increased risk of adding/upgrading or decreased risk of downgrading an outcome when the conclusion was positive.
Number of systematic reviews included 96
Number of eligible systematic reviews assessed 2426
Treatment impacted Yes
Treatment impacted description
Interpretation impacted No
Interpretation impacted description