Study-based registers of randomized controlled trials: Starting a systematic review with data extraction or meta-analysis

Despite years of use of study-based registers for storing reports of randomized controlled trials (RCTs), the methodology used in developing such registers/databases has not been documented. Such registers are integral to the process of scientific reviewing. We document and discuss methodological aspects of the development and use of study-based registers. Although the content is focused on the study-based register of randomized/controlled clinical trials, this work applies to developers of databases of all sorts of studies related to the human, animals, cells, genes, and molecules.
We describe necessity, rationale, and steps for the development, utilization and maintenance of study-based registers as well as the challenges and gains for the organizations supporting systematic reviews of the published and unpublished literature.
The ultimate goal of having a study-based register is to facilitate efficient production of systematic reviews providing rapid, yet accurate, evidence for the decision-makers. We argue that moving towards study-based registers is an inevitable welcome direction and that infrastructures are ready for such movement.