To the Editor,
The article by Smaïl-Faugeron et al. sheds light on the need for specific mechanisms to inform oral health researchers about the importance of clinical trial registration (Smaïl-Faugeron et al. 2015). We wholeheartedly agree with their plea and hope that this important report spurs action within the dental community. Moreover, we have identified 2 areas that could have strengthened the submission.
Trial registration has been proposed as a potential solution to prevent biased reporting in clinical trials (Hardt et al. 2013). It aimed at reducing 2 main sources of bias: publication bias and selective reporting (Wager et al. 2013), the latter having been included in one of the 6 domains of the Cochrane Collaboration Risk of Bias (RoB) tool (Higgins and Altman 2008; Higgins et al. 2011). The article in question, though, examined the risk of bias based on only 2 domains of the RoB tool (sequence generation and allocation concealment) that are not directly related to trial registration, while not considering the main domain of the tool (selective reporting) that assesses reporting bias. It is not clear why the authors chose to do so.
Furthermore, the authors classified journals into 3 categories, based on a screening performed in December 2013 using the journals’ Web sites, while including trials published in 2013. This procedure might have created a sampling bias affecting the findings, because some trials might have been submitted in 2011/2012 when the rules were not in place, and published in 2013 when the rules were in effect. Last, the authors could have confirmed with the journals directly about the specific date after which regulation for clinical trial registration was required.
Footnotes
The authors received no financial support and declare no potential conflicts of interest with respect to the authorship and/or publication of this article.
References
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