Scarce quality assurance documentation in major clinical trial registries for approved medicines used in post-marketing clinical trials.

Background: This research reviewed major Clinical Trial Registries (CTRs) and assessed the availability of fields on quality assurance for approved medicines used as Investigational Medicinal Products (IMPs) in phase IV clinical trials.

Methods: Two reviewers independently assessed CTRs of the International Committee of Medical Journal Editors (ICJME) and of World Health Organization (WHO) platforms. Each CTR was checked by two reviewers on availability of fields on brand name, manufacturer's name, approval status, approving authority, compliance with Good Manufacturing Practices, and quality testing.