| Ref ID | 458 |
| First Author | M. Baudard |
| Journal | BMJ |
| Year Of Publishing | 2017 |
| URL | https://www.bmj.com/content/bmj/356/bmj.j448.full.pdf |
| Keywords |
• Grey literature • Pharmacological |
| Problem(s) |
• Lack of supplementary searches beyond databases |
| Article Type | Empirical |
| Article Subtype | Meta-epidemiological analysis |
| First Author Country | France |
| Aim | To assess the impact of searching clinical trial registries in systematic reviews of pharmaceutical treatments that include meta-analyses published in MEDLINE between June 2014 and January 2015. When additional data were retrieved, two independent researchers reanalysed meta-analyses and calculated the weight of the additional trials and the change in summary statistics by comparison with the original meta-analysis. |
| Level of Investigation | Descriptive |
| Summary of Findings | 52% of included reviews did not report a search of trial registries. For a subset of 95 systematic reviews, 43% were found to have additional data from 122 additional randomised controlled trials when searches were performed. The change in summary statistics ranged from 0% to 29% and was greater than 10% for five of 14 systematic reviews and greater than 20% for two. However, none of the changes to summary effect estimates led to a qualitative change in the interpretation of the results once the new trials were added. |
| Number of systematic reviews included | 223 |
| Number of eligible systematic reviews assessed | 2249 |
| Treatment impacted | Yes |
| Treatment impacted description | |
| Interpretation impacted | No |
| Interpretation impacted description |