The fourth edition of the AHRQ publication, "Registries for Evaluating Patient Outcomes: A User's Guide," is a reference handbook that provides best practices to guide design, operation, analysis, and evaluation of patient registries. First published in 2007, the User's Guide was expanded and revised in 2010 and 2014 to address new issues in registry methodology.

Since the publication of the first edition, registries have evolved significantly in response to technical and cultural shifts in the clinical research environment. Registries have been adapted to take advantage of the widespread use of electronic health record (EHR) systems and the ability to reuse EHR data for research purposes. Many registries now extract data directly from EHRs, thereby reducing the burden of participation and enabling registries to enroll much larger patient populations. While the use of existing data sources has many advantages, interoperability challenges remain, and use of these data introduces new considerations into the planning, design, operation, and analysis of registries.

In parallel with these technological changes, registries have been adapted to respond to the emergence of patient-centered outcomes research and the increasing recognition that patients must at the center of clinical research studies. Some registries have added patient representatives to advisory boards, while others have added patient-centered outcomes, such as patient-reported outcomes or other outcome measures, to the registry data collection in response to patient feedback. Patient organizations also have founded a growing number of patient registries. As with the use of existing data sources, the move toward including patients in all phases of registry design and operations brings many advantages but also introduces new considerations.

The fourth edition, published in September 2020, provides concise, practical information to help registries address these and other changes. Among other highlights, the fourth edition:

• Focuses on the fundamentals of registry planning, design, operations, and analysis, with an emphasis on how registries can use existing data sources and how to collaborate with patients across the registry lifecycle.
• Recognizes the move toward data standards and includes a new chapter on using common data elements and standardized outcome measures.
• Includes a new chapter on governance that addresses issues around reusing existing data sources and shares insights on effective engagement with a wide range of stakeholders, including patient representatives.
• Updates chapters on ethics, privacy, and informed consent to address the revised Common Rule.
• Revises the chapter on evaluating registries to reflect new considerations related to using existing data sources and the increasing interest in using registries as sources of real-world data and real-world evidence for informing decision making.