Influenza virus infection most commonly causes acute respiratory tract illness, however may also lead to non-respiratory complications including acute cardiovascular (CV) events. We describe the frequency of and risk factors for acute CV events in adults hospitalized with influenza in the United States.

We included adults aged > 18 years hospitalized during influenza seasons 2010–2011 through 2017–2018 in FluSurv-NET, a multi-state population-based surveillance system that includes detailed medical chart review of patients hospitalized with laboratory-confirmed influenza. We defined acute CV events by International Classification of Diseases (ICD) primary and secondary discharge diagnosis codes for acute heart failure (aHF), acute ischemic heart disease (aIHD), hypertensive crisis, cardiogenic shock, acute myocarditis, acute pericarditis and cardiac tamponade. We calculated the frequency of acute CV events and used multivariable logistic regression among the 87% treated with influenza antivirals to identify independent factors associated with aHF and aIHD, the two most common diagnoses.

Of 80,374 adults hospitalized with laboratory-confirmed influenza, 12% had > 1 acute CV event. We found that aHF (46%) and aIHD (42%) were the most common, followed by hypertensive crisis (8%), cardiogenic shock (3%), acute myocarditis (0.7%), acute pericarditis (0.4%) and cardiac tamponade (0.2%). Compared with treated patients without an acute cardiovascular event, treated patients with aHF (Figure A) and aIHD (Figure B) were more likely to be older, currently/formerly use tobacco and have underlying conditions including cardiovascular disease, diabetes mellitus, and kidney disease.

Among adults hospitalized with laboratory-confirmed influenza, acute CV events are common, particularly among those with prior cardiovascular disease. During the influenza season, clinicians should consider influenza virus infection in hospitalized adults who present with acute CV events. Non-respiratory complications, specifically aHF and aIHD, may be an under-recognized contributor to the burden of influenza.

All authors: No reported disclosures.