Journal of clinical epidemiology
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Comparative Study Pragmatic Clinical Trial
PRECIS-2 for retrospective assessment of RCTs in systematic reviews.
A randomized controlled trial (RCT) may be intended either to support real-world decisions on choice between alternative interventions or to help researchers understand mechanisms of action of an intervention. PRECIS-2 is widely used to help investigators match detailed design elements to their main intention for that RCT. PRECIS-2 is increasingly being used retrospectively for assessing RCTs within reviews. In this commentary, we counter arguments that RCTs with a placebo control group, masking/blinding of participants or providers, or conducted in a single center should be retrospectively assessed as completely explanatory, overriding a detailed PRECIS-2 assessment. We also counter arguments that a trial cannot be assessed using only the main peer-reviewed trial report. ⋯ PRECIS-2 can be used for retrospective assessments of trials in systematic reviews. The PRECIS-2 instrument should be expanded by including a domain describing the control group(s). Published RCT reports are suitable for retrospective PRECIS-2 assessments.
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It is now more than 50 years since the concepts of explanatory and pragmatic attitudes toward trials were first discussed by Schwartz and Lellouch in their influential 1967 paper. Since then, there has been increasing focus on design aspects that may be consistent with more pragmatic attitudes within clinical trials, and a number of tools developed to assist investigators prospectively think about their trial design. Researchers have subsequently expressed interest in using these tools retrospectively to characterize trials as pragmatic or explanatory. ⋯ The practical implication of our suggestion for trial reporting is that investigators should explicitly state the intent of the trial through a clear articulation of the decision that they hope will be informed by the trial results. This should be coupled with a completed PRagmatic-Explanatory Continuum Indicator Summary 2 assessment (or similar) with an explanation of study design choices to appropriately assess whether the study design is consistent with the study intent. We believe this will assist reviewers and knowledge users in making assessments of trials.