Top Things to Know: Observational Comparative Research in Cardiovascular and Brain Health & Disease
Updated: May 20, 2026
Prepared by Brian Mac Grory, MD and Anne Leonard, MPH, RN, National Sr. Science & Medicine Advisor, American Heart Association
- Resources for observational comparative research particularly in cardiovascular disease and brain health have rapidly expanded to include large, granular healthcare datasets and advanced analytical methods.
- There are many data sources that capture detailed clinical data for many millions of patients in a limited/de-identified fashion.
- Observational research can be a powerful tool to study rare conditions and the real-world impact of treatments outside of clinical trials.
- Sources of systematic error or bias in observational comparative studies include selection bias, information bias, and confounding and these need to be identified in these studies.
- Techniques from statistics and economics can be used in innovative ways to help understand and partially mitigate bias
- Doing high quality observational comparative research is a collaborative pursuit requiring clinicians, statisticians, methodologists, and data scientists.
- All specialties bring distinct and complementary expertise to observational comparative research depending on the subject.
- All observational comparative studies should be interpreted with caution.
- The highest quality observational comparative studies are those that are planned well in advance, report their results transparently, and disclose their limitations
- This scientific statement provides an overview of best practices and analytic considerations in observational comparative studies from the perspective of investigators, sponsors, publishers, and consumers of observational research and is applicable to all areas of cardiovascular, stroke and brain health research.
Citation
Mac Grory B, Yeh RW, Beckman JA, Kamel H, Lusk JB, Otto CM, Shi J, Smith EE, Xian Y, Zachrison KS; on behalf of the American Heart Association Stroke Council; Council on Clinical Cardiology; Council on Peripheral Vascular Disease; and Council on Quality of Care and Outcomes Research. Observational comparative research in cardiovascular and brain health and disease: a scientific statement from the American Heart Association. Circulation. Published online May 20, 2026. doi: 10.1161/CIR.0000000000001440