While it is well known that COVID-19 can impact the heart’s muscle, less is understood about influenza’s potential for myocardial involvement. To explore this gap, a recent study led by the CVC’s Dr. Finlay McAlister investigated how often patients hospitalized with either influenza or COVID-19 showed elevated biomarkers and were diagnosed with new cardiac conditions.
Researchers conducted a retrospective cohort study, drawing on administrative and clinical data from April 2015 to March 2023. The study included all adults hospitalized with influenza or COVID-19 in 29 Ontario hospitals that were part of the GEMINI hospital research collaborative. They employed multivariable regression and other statistical tools to compare troponin and natriuretic peptide levels, as well as new cardiac diagnoses that emerged during initial hospitalizations.
In this study, 25,200 COVID-19 patients were generally younger, more often male, and had less pre-existing cardiovascular disease than the 8,568 influenza patients. Although biomarkers like troponin and natriuretic peptides were more frequently measured in COVID-19 patients, their levels weren’t more likely to be elevated than the influenza patients. Furthermore, new clinical diagnoses such as heart failure or atrial fibrillation were not significantly different between those infected with COVID-19 and influenza. Overall, approximately two-fifths of both patient groups exhibited elevated troponin, and about three-fourths had elevated natriuretic peptides.
Despite low rates of newly diagnosed heart conditions like heart failure, atrial fibrillation, acute myocardial infarction, and myocarditis, the study revealed a significant finding: probable heart failure, detected by sensitive biomarkers, was nearly 20 times more frequent than clinically recognized diagnoses in both patients with influenza and those with COVID-19. This discrepancy suggests that myocardial involvement with both infections is far more common than previously assumed. The researchers advocate for routine biomarker testing in all hospitalized patients with either virus, allowing for earlier detection of these subclinical conditions and, ultimately, more timely and effective management.
