Risk of Cardiovascular Events After Influenza: A Population-Based Self-Controlled Case Series Study, Spain,...

Area of Science:

• Epidemiology
• Cardiovascular Medicine
• Infectious Diseases

Background:

• Influenza is a significant public health concern.
• Atherothrombotic events, including myocardial infarction and ischemic stroke, are leading causes of morbidity and mortality.
• The potential link between influenza infection and atherothrombotic events requires further investigation.

Purpose of the Study:

• To investigate the association between influenza infection and atherothrombotic events.
• To quantify the risk of acute myocardial infarction and ischemic stroke following influenza.
• To explore the impact of influenza severity and patient risk factors on this association.

Main Methods:

• A population-based self-controlled case series design was employed.
• Individual-level data from electronic health registries in Spain (n = 2,230,015) were utilized.
• Analyses included sensitivity analyses to support causality.

Main Results:

• Influenza infection was associated with a more than 2-fold increased risk of atherothrombotic events within 14 days after mild cases in lower-risk individuals.
• The risk increased more than 4-fold after severe influenza cases in vulnerable patients.
• This elevated risk persisted for over 2 months in vulnerable populations.

Conclusions:

• Influenza infection is causally linked to an increased risk of atherothrombotic events.
• The risk is dose-dependent on influenza severity and patient vulnerability.
• Strengthening influenza vaccination recommendations for at-risk groups and public awareness of milder infections are crucial.