Importance: Influenza is associated with an increased risk of cardiovascular events, but to our knowledge, few studies have explored the temporal association between influenza activity and hospitalizations, especially those caused by heart failure (HF). Objective: To explore the temporal association between influenza activity and hospitalizations due to HF and myocardial infarction (MI). We hypothesized that increased influenza activity would be associated with an increase in hospitalizations for HF and MI among adults in the community. Design, Setting, and Participants: As part of the community surveillance component of the Atherosclerosis Risk in Communities (ARIC) study, a population-based study with hospitalizations sampled from 4 US communities, data were collected from 451588 adults aged 35 to 84 years residing in the ARIC communities from annual cross-sectional stratified random samples of hospitalizations during October 2010 to September 2014. Exposures: Monthly influenza activity, defined as the percentage of patient visits to sentinel clinicians for influenza-like illness by state, as reported by the Centers for Disease Control and Prevention Surveillance Network. Main Outcomes and Measures: The monthly frequency of MI hospitalizations (n = 3541) and HF hospitalizations (n = 4321), collected through community surveillance and adjudicated as part of the ARIC Study. Results: Between October 2010 and September 2014, 2042 (47.3%) and 1599 (45.1%) of the sampled patients who were hospitalized for HF and MI, respectively, were women and 2391 (53.3%) and 2013 (57.4%) were white, respectively. A 5% monthly absolute increase in influenza activity was associated with a 24% increase in HF hospitalization rates, standardized to the total population in each community, within the same month after adjusting for region, season, race/ethnicity, sex, age, and number of MI/HF hospitalizations from the month before (incidence rate ratio, 1.24; 95% CI, 1.11-1.38; P <.001), while overall influenza activity was not significantly associated with MI hospitalizations (incidence rate ratio, 1.02; 95% CI, 0.90-1.17; P =.72). Influenza activity in the months before hospitalization was not associated with either outcome. Our model suggests that in a month with high influenza activity, approximately 19% of HF hospitalizations (95% CI, 10%-28%) could be attributable to influenza. Conclusions and Relevance: Influenza activity was temporally associated with an increase in HF hospitalizations across 4 influenza seasons. These data suggest that influenza may contribute to the risk of HF hospitalization in the general population.
Bibliographical noteFunding Information:
In a sensitivity analysis, we analyzed the correlation between ILI activity at the state level in North Carolina and at the county level in Forsyth County, North Carolina. County-level data were not available for the other ARIC communities. Influenza-like illness activity in Forsyth County was reported by the North Carolina Department of Health and Human Services/Department of Public Health Disease Event Tracking and Epidemiologic Collection Tool (NC DETECT), which is an advanced, statewide public health surveillance system that is funded by the North Carolina Division of Public Health and Public Health Emergency Preparedness Grant and managed through collaboration between the North Carolina Division of Public Health and the University of North Carolina at Chapel Hill Department of Emergency Medicine's Carolina Center for Health Informatics.
personal fees from Sanofi-Pasteur, Sanofi-Aventis, Amgen, and Boehringer-Ingelheim; grants and personal fees from Novartis and AstraZeneca; and grants to his institutions from AstraZeneca, Novartis, and Sanofi. Dr Temte reported personal fees from Sanofi Pasteur and CSK. Dr Solomon reported grants from Alnylam, Amgen, AstraZeneca, Bellerophon, Bayer, BMS, Celladon, Cytokinetics, Eidos, Gilead, GSK, Ionis, Lone Star Heart, Mesoblast, MyoKardia, National Institutes of Health/National Heart, Lung, and Blood Institute, Novartis, Sanofi Pasteur, and Theracos and personal fees from Akros, Alnylam, Amgen, AstraZeneca, Bayer, BMS, Cardior, Corvia, Cytokinetics, Gilead, GSK, Ironwood, Merck, Novartis, Roche, Takeda, Theracos, Quantum Genetics, Cardurion, AoBiome, Janssen, Cardiac Dimensions, and Tenaya. Dr Vardeny reported grants from Sanofi Pasteur. No other disclosures were reported.
Communities Study has been funded in whole or in part with federal funds from the National Heart, Lung, and Blood Institute, National Institutes of Health, and the Department of Health and Human Services (contract IDs: HHSN268201700001I, HHSN268201700002I, HHSN268201700003I, HHSN268201700005I, and HHSN268201700004I).