| Ref ID | 141 |
| First Author | M. J. Page |
| Journal | THE COCHRANE LIBRARY |
| Year Of Publishing | 2014 |
| URL | https://pubmed.ncbi.nlm.nih.gov/25271098/ |
| Keywords |
• General medical • Protocols • Pre-specification • Cochrane • Multiplicity |
| Problem(s) |
• Multiplicity of outcomes and lack of pre-specification for outcome reporting • Undocumented or unjustified deviations to the review protocol |
| Article Type | Empirical |
| Article Subtype | Meta-epidemiological analysis |
| First Author Country | Australia |
| Aim | To assess the results of empirical studies that have investigated the prevalence of selective inclusion or reporting in systematic reviews of randomised controlled trials, and investigated the factors (e.g. statistical significance or direction of effect) associated with the prevalence and quantified the bias indexed across several databases up to May 2013. |
| Level of Investigation | Analytical |
| Summary of Findings | Based on a meta-analysis of four of the seven included studies (which included 485 Cochrane Reviews), 38% (95% confidence interval (CI) 23% to 54%) of systematic reviews added, omitted, upgraded or downgraded at least one outcome between the protocol and published systematic review. The association between statistical significance and discrepant outcome reporting between protocol and published systematic review was uncertain. The meta-analytic estimate suggested an increased risk of adding or upgrading (i.e. changing a secondary outcome to primary) when the outcome was statistically significant, although the 95%CI included no association and a decreased risk as plausible estimates (RR 1.43, 95% CI 0.71 to 2.85; two studies, n = 552 meta-analyses). Also, the meta-analytic estimate suggested an increased risk of downgrading (i.e. changing a primary outcome to secondary) when the outcome was statistically significant, although the 95% CI included no association and a decreased risk as plausible estimates (RR 1.26, 95% CI 0.60 to 2.62; two studies, n = 484 meta-analyses). |
| Number of systematic reviews included | 485 |
| Number of eligible systematic reviews assessed | 4460 |
| Treatment impacted | Yes |
| Treatment impacted description | |
| Interpretation impacted | Yes |
| Interpretation impacted description | The meta-analytic estimate suggested an increased risk of adding or upgrading (i.e. changing a secondary outcome to primary) when the outcome was statistically significant, although the 95%CI included no association and a decreased risk as plausible estimates (RR 1.43, 95% CI 0.71 to 2.85; two studies, n = 552 meta-analyses). |