The goal of both a clinical trial and of a patient registry is to produce evidence for scientific advancement, regulatory approval, and/or clinical decision-making. Producing sufficient evidence will yield a best practice or a clinical guideline that establishes a standard of care.
Evidence can be produced in a variety of ways. At the top of the pyramid are clinical trials and prospective cohort studies. A clinical trial provides a test of a hypothesis to produce an efficacy statement that the intervention improves outcomes. It establishes a mechanistic efficacy associated with a clinical outcome and the intervention is safe.
Registries, on the other hand, can do several things, including:
- Provide evidence prior to a clinical trial,
- Serve as a “substitute” for a clinical trial when a trial is not feasible, and
- Establish the comparative effectiveness of different treatment methodologies.
Registries are a way to start, to demonstrate utility, and to provide effectiveness in a more generalizable setting.
What is a Patient Registry?
A registry is a protocol-driven collection of uniform, well-defined data. This data can include demographics, diagnostic test results, pathology classifications, treatments, and outcomes. A registry is designed with a scientific, clinical, or policy purpose in mind. The data is collected from a variety of sources such as direct observation, electronic medical records, claims data, discharge summaries, and follow-up evaluations such as patient questionnaires and surveys. Registries accumulate data consistent with the flow of diagnosis and care.
Because data is collected for a purpose, it should be defined in advance. Standardized measures are strongly encouraged to facilitate sharing and comparing of the data. The National Library of Medicine has established a Common Data Elements repository conditions. The National Institutes of Health has established the Patient-Reported Outcomes Measurement Information System (PROMIS). The National Center for Health Statistics also has several well-validated surveys and instruments. Registries also represent opportunities to establish new clinimetrics and collect data about patients, procedures, and outcomes specific to condition or treatment.
How Can a Patient Registry Be Used?
Registries in public health can be used to track the incidence and prevalence of a particular disease or condition. Registries also allow for the accumulation of data for rare conditions across multiple institutions. And, registries can be used to combine data from multiple sources and to examine patient characteristics, treatment practices and outcomes across the health sector.
Registries are useful for the evaluation of various treatments, ultimately helping to refine the optimal treatment modality. For example, with focused ultrasound, providers may manage and treat patients differently in terms of intensity and duration. A registry can capture these variations so that researchers can analyze which method is more frequent and more prognostic of outcome.
Registries also can determine the differential response of patients. The data may elucidate prognostic factors or help refine the outcome measure. A major step toward registry utilization has been the development of comparative effectiveness research and methods to assess comparability. And finally, registries can be used for trials where randomization is not possible, where a larger, more generalizable patient population is needed, or to compare effectiveness of several established treatments in clinical outcome, safety, and cost.
For focused ultrasound, registries provide insights into how treatment can be applied and whether it is feasible. The pancreatic cancer registry and the pediatric bone tumor registry will demonstrate whether a certain procedure or multiple procedures improve pain, survival, and quality of life. The prostate cancer registry will provide measures of the long-term effectiveness in a large number of patients of high intensity focused ultrasound. The yield of these registries will be increased, evidenced-based effectiveness and the expansion of the scope of focused ultrasound.
James Torner, PhD, is a Professor of Epidemiology, Surgery, and Neurosurgery and Associate Director of the Institute for Clinical and Translational Science at the University of Iowa. He has conducted research in clinical trials and registries with application in women’s health, and disability related to injuries and clinical conditions. He has been teaching, designing, and conducting clinical trials for four decades.