View source for Registry-based trials

= Registry-Based Trials =

'''Registry-based trials''' are randomized controlled trials (RCTs) that use data from existing patient registries to support key trial processes such as participant identification, [[randomization]], data collection, and outcome assessment. By embedding trials within real-world data systems, they aim to increase efficiency, reduce costs, and improve generalizability.

== When are they used? ==
Registry-based trials are conducted when a high-quality clinical or administrative registry is available, routinely maintained, and contains data relevant to the [[research question]]. They are particularly useful when the target population is already captured within the registry and the outcomes of interest are regularly recorded. These trials are often chosen for pragmatic questions, comparative effectiveness research, and studies requiring long-term follow-up. They are especially valuable when testing low-risk interventions already in clinical use and when trial efficiency and scalability are priorities.

== Key Features ==
The central feature of registry-based trials is the use of existing data infrastructure. Randomization is often conducted within the registry itself, and outcomes are measured using data already collected for clinical or administrative purposes. These trials may be open-label or blinded depending on feasibility. By embedding research into usual care, they allow for large-scale, cost-effective studies with minimal disruption to clinical practice. Additional data, such as [[informed consent]] or adherence, may be collected outside the registry when necessary.

== Design Considerations ==
The quality, completeness, and reliability of registry data are crucial to the success of a registry-based trial. Researchers must assess whether the registry includes necessary baseline covariates, intervention details, and outcome measures. While trial-specific procedures may be limited, ethical approvals and governance structures must still be addressed. Data linkage between multiple registries (e.g., hospital, pharmacy, death records) may be required. Flexibility is often limited, and attention must be paid to data privacy, [[missing data]], and real-time data access.

== Strengths ==
Registry-based trials offer several advantages, including lower cost, faster recruitment, and enhanced generalizability. They reduce the burden on healthcare providers and participants by relying on routinely collected data. These trials are ideal for large sample sizes and extended follow-up, making them well suited for evaluating the real-world effectiveness and safety of interventions.

== Limitations ==
Limitations include dependency on the quality of registry data and reduced ability to capture nuanced clinical or [[patient-reported outcomes]]. Incomplete or inaccurate data can threaten validity. Trialists may have less control over timing and standardization of data collection. Data governance, consent, and privacy concerns must also be carefully managed, particularly in jurisdictions with strict data-sharing regulations.

== Example ==
A national cardiovascular registry might be used to evaluate two commonly prescribed antihypertensive medications. Eligible patients are identified through the registry and randomized to one of two treatment arms. Outcomes such as myocardial infarction and stroke are then assessed using routinely collected follow-up data, with no need for additional site visits or bespoke data collection systems.

== Related Pages ==
* [[Pragmatic trials]]
* [[Cluster randomized trials]]

=== Bibliography ===
# Lauer MS, D’Agostino RB. The randomized registry trial — The next disruptive technology in clinical research? ''New England Journal of Medicine''. 2013;369(17):1579–1581.
# James S, Rao SV, Granger CB. Registry-based randomized clinical trials—a new clinical trial paradigm. ''Nature Reviews Cardiology''. 2015;12(5):312–316.
# Li G, Sajobi TT, Menon BK, et al. Registry-based randomized controlled trials—what are the advantages, challenges, and areas for future research? ''Journal of Clinical Epidemiology''. 2016;80:16–24.

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''Adapted for educational use. Please cite relevant trial methodology sources when using this material in research or teaching.''