Both electronic health records (EHRs) and patient registries store and use patient-related clinical information. However, they are conceptualized for different purposes. Both are a significant source of real-world evidence (RWE) as they gather a considerable amount of clinical information collected in the real-world setting.

An EHR is an electronic record of health data generated during routine patient care delivered by healthcare providers.(1) EHRs are widely used to obtain information on several medical parameters from patients and maintain clinical workflows.(2) They usually comprise data on patients’ demographic, vitals, administrative, claims (medical and pharmacy), and clinical parameters. They also include other patient-related information, such as data from health-related quality-of-life instruments, home-monitoring devices, and caregiver assessments.(3)

EHRs usually represent individual care structures, such as primary, emergency, and intensive care units, and are visit-oriented and transferable. They also offer data from integrated systems in single or linked hospitals.(4) As the use of EHRs becomes extensive in clinical research, it is only ideal that they are designed to enhance diagnosis and clinical care to improve their relevance further. The design of EHRs can also update with time as the technology advances or depending on external factors, such as changes in data type as per coding or reimbursement patterns.(1, 3)

A patient registry is “an organized system that uses observational study methods to collect uniform data (clinical and other) to evaluate specified outcomes for a population defined by a particular disease, condition, or exposure and that serves one or more predetermined scientific, clinical, or policy purposes.”(1) Patient registries are crucial in research as an ultimate platform for focused information about patients with specific health conditions. They often also help answer questions otherwise not answered by randomized clinical trials (RCTs), owing to practicality or ethicality. Registry data also help reduce the time and cost of prospective data collection. RWD generated in registries enables hypotheses generation in research, thus helping descriptive studies and research in health services.(5) Registries are typically patient-oriented and goal-driven. They are designed to collate information on specific exposures and health outcomes. Patient registries can be population-based or hospital-based.

Often data captured from EHRs are used to construct patient registries. Specifically, EHRs can facilitate certain functions for patient registries, such as collection, cleaning, and storage of data. Likewise, a registry can enhance the value of the information gathered in the EHRs, for instance, comparative effectiveness, safety, and value, population management, and quality reporting, among others.(6)

Data from EHRs, either as stand-alone or as complementary information to the primary research or data from administrative databases, have been used to support observational studies. For instance, the Euro Heart Survey (7), the Eurobservational Research Program (EORP) which followed the survey,(8) and the AHA Get With the Guidelines (AHA GWTG) (9) show clinical information from EHRs on several cardiovascular diseases.(3) Moreover, the EU-ADR project connects eight databases from four European countries (United Kingdom, Italy, The Netherlands, and Denmark) to facilitate the analysis of specific target adverse drug reactions (ADRs).(10) The USFDA uses data from EHRs from various sources, including sentinel systems,(11) claims databases (Medicare and Medicaid Services), and Veterans Affairs, among others, to support safety investigations for products after marketing approvals.(12)

Many clinical registries across the globe comprise patient data on acute and chronic stages of different diseases, such as cancer, cystic fibrosis, and multiple sclerosis, to name a few. For instance, countries like the US, Canada, Australia, Germany, Sweden, and Argentina, have registries to monitor and store patient data on acute stroke. The Cystic Fibrosis Foundation Patient Registry is a clinical quality registry (CQR), developed from an epidemiological and clinical research model.(13) The American Heart Association (AHA) recommends 5 key concepts in establishing patient registries: ensuring high quality data, linking registries with relevant supplemental data, integrating registries with EHRs, safeguarding privacy, and funding considerations.(14) CQRs have also been reported to contain extensive clinical information that can complement data from government-monitored registries. These data are vital for assessing the quality of care and research.(5, 15)

Clinical data from both EHRs and registries can generate meaningful evidence to enhance trial efficiency and optimize novel research approaches. These RWD sources can help comparative effectiveness research while facilitating new trial designs to address unmet clinical needs. Their use seems hopeful. However, the technological advancements in these sources need to be looked at with applicable care measures to ensure data privacy and confidentiality.

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  2. Gliklich R, Dreyer N, Leavy M, eds. Registries for Evaluating Patient Outcomes: A User’s Guide. Third edition. Two volumes. (Prepared by the Outcome DEcIDE Center [Outcome Sciences, Inc., a Quintiles company] under Contract No. 290 2005 00351 TO7.) AHRQ Publication No. 13(14)-EHC111. Rockville, MD: Agency for Healthcare Research and Quality. April 2014. Available from: http://www​
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  13. Schechter MS, Fink AK, Homa K, Goss CH. The Cystic Fibrosis Foundation Patient Registry as a tool for use in quality improvement. BMJ quality & safety. 2014; 23(Suppl 1):i9–i14.
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