Using two studies describing adverse cardiovascular outcomes and mortality with the use of peri-operative beta-blockers, Dr. Burack describes both effect modification and confounding.
Presentation: Effect Modification and Confounding
Article #1: Association of β-Blocker Therapy With Risks of Adverse Cardiovascular Events and Deaths in Patients With Ischemic Heart Disease Undergoing Noncardiac Surgery A Danish Nationwide Cohort Study
Brief Summary: A simplistic approach to a patient with multiple risk factors would be to say that the effect of one factor simply adds to the effect of the other. This is the basis of the additive model. While this is true in some situations, we know that relationships are often more complex. Effect modification describes the phenomenon in which the effect of one factor depends on the status of the other. Additionally, confounding is when the apparent effect of one factor is attributable to its service as a marker for another “causal” factor. Read the articles and presentation above to gain a fuller understanding of each of these terms and how to actively apply that knowledge to your everyday learning.
Feel free to share your thoughts in the comments section below. Please email Dr. Burack if there are any specific questions you would like to ask him or if you need clarification.