Knowledge synthesis: How to improve the use of evidence from clinical trials?

Abstract

Background: The value of systematic reviews (SRs) is determined by methodology and reporting quality of primary studies and how the SR is conducted and reported. Aim: This study discusses key aspects of clinical trials (CTs) that might affect the value of SRs. Design: Narrative review. Results: We highlighted the following CT factors that could affect SR value: Defining the purpose of CTs is important because it could directly impact whether an SR question is appropriately answered and formulated; choose the most appropriate intervention to answer a proposed SR question is critical because we can exclude or include different studies, directly influencing selection bias; when conducting SRs, the study's search must be restricted to equal or highly similar comparison groups, allowing suitable comparisons of the outcomes’ estimates; in SRs, it may be interesting to explore the effect of the most common definition of the disease used in clinical practice, being useful in evidence-based dentistry and easily translated to daily practitioners; and deficiencies in CT reporting can lead to unusable reports, biased results, and conclusions. Conclusion: All aspects discussed were found to be important for improving the use of evidence from CTs.