A methodological review identified several options for utilizing registries for randomized controlled trials.

Objectives: Registry-based randomized controlled trials (RRCTs) can provide internally valid results in a real-world context at relatively low effort and cost. However, the main characteristics, the extent to which the registry is utilized (eg, proportion of data from registry) and registry-related limitations are not well characterized. This methodological review of RRCTs aims to analyze the trial design features, investigate potential usage options, and identify possible limitations of using registry data for randomized controlled trials (RCTs).