Interpretation
Previous empirical evaluations have focused on one or a few aspects of
some of the items that were considered in our eight usefulness criteria.
For example, there are several empirical studies examining the conduct
of systematic reviews preceding a trial (17,18), the use of power
calculations (19), pragmatism (12) and use of transparency practices
such as protocol and data sharing, registration, disclosures of funding
and conflicts of interest.(20,21) However, our evaluation provides a
composite assessment across multiple domains in a scale that is
unprecedented and offers a wider view. For PTB research there is no
prior empirical evaluation of most of these usefulness features, but
there is definitely awareness of the problems arising from lack of these
features.(22) One study for example evaluated the effect of
pre-registration and its impact on reducing selective outcome reporting
in trials and meta-analysis evaluating progesterone for PTB prevention.
This study identified 93 RCTs and 29 systematic reviews and found a
remarkable difference in the reported effectiveness of progesterone when
evaluating the subset of trials reporting a pre-registered primary
outcome only (n=22), compared to the totality of trials and reviews.(23)
This example highlights the importance of addressing preregistration,
protocol and data availability. Sadly, these transparency features still
represent a minority of the 138 trials published between 2010 to 2019
assessed in the current project.