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Comment & Response
July 10, 2019

Interactions Between Influenza and Heart Failure Hospitalizations—Diagnostic and Pathogenetic Issues—Reply

Author Affiliations
  • 1Cardiovascular Division, Brigham and Women’s Hospital, Boston, Massachusetts
  • 2Minneapolis Veterans Affairs Health Care System, Minneapolis, Minnesota
  • 3University of Minnesota, Minneapolis
JAMA Cardiol. 2019;4(9):950. doi:10.1001/jamacardio.2019.2220

In Reply We found that in a community surveillance study, an increase in influenzalike illness (ILI) activity was associated with an increased rate of hospitalization for heart failure (HF) but no significant increase in hospitalizations for myocardial infarction.1 Because of the nature of the Atherosclerosis Risk in Communities study surveillance data, we could not determine vaccination status of individual hospitalized patients. To account for the protective effects of vaccination, we further adjusted for the percentage of the population vaccinated at the state level as reported by the US Centers for Disease Control and Prevention FluVaxView in addition to the covariates in our original model. Vaccine coverage estimates were based on several representative surveys: the Behavioral Risk Factor Surveillance System, National Health Interview Survey, and National Immunization Survey–Flu.2 The association of ILI with HF did not change significantly after adjusting for population-level influenza vaccination coverage (overall incidence rate ratio, 1.20; 95% CI, 1.07-1.24). Additionally, we examined the association of ILI with fatal HF hospitalizations to assess whether there was an increased mortality risk and found no significant association (incidence rate ratio, 1.00; 95% CI, 0.72-1.39). Nevertheless, the vaccination coverage estimates are limited by low survey response and self-report.2 Additionally, there were substantially fewer fatal HF hospitalizations than total HF hospitalizations (569 vs 4321) during our study period, likely resulting in insufficient power to detect a signal.

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