Association between Influenza-like illness and acute myocardial
infarction patients: A case-control study
Abstract
Background: Acute myocardial infarction (AMI) is the leading cause of
death worldwide. Seasonal Influenza can lead to cardiovascular
complications. Thus, the association between Influenza and
cardiovascular events has been of interest recently. Hypothesis:
Therefore, this study aimed to investigate recent influenza-like
illnesses (ILI) in acute myocardial infarction (AMI) patients compared
to other hospitalized patients as the control group during the cold
season in the north of Iran. Methods: This retrospective case-control
study included 300 patients (150 AMI patients and 150 controls) aged ≥
50 years hospitalized for acute myocardial infarction (AMI) or other
conditions between September 22, 2019, and March 15, 2020. Patients in
each group were frequency-matched for gender and age range. The primary
exposure was a recent ILI (fever ≥ 37.8°C, cough, and sore throat) in
the past month. Results: The patients’ mean age was 64.42 ± 9.47 years,
with a range of 50-94 years. Overall, forty-five (15%) patients of 300
participants had diseases that met the ILI criteria. The AMI group
patients significantly reported more ILI than controls (adjusted OR:
3.04, 95% CI: 1.02 to 9.09, p < 0.001). On the other hand,
patients who received the influenza vaccine were significantly less
likely to have an acute myocardial infarction than those who did not
receive the vaccine (adjusted OR: 0.02, 95% CI: 0.001 to 0.38, p =
0.006). Conclusion: In conclusion, the present study demonstrates that
ILI can increase the risk of AMI. Also, it was confirmed that Influenza
vaccination could reduce the risk of AMI.