Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2025 Mar 17;80(3):e43-e45.
doi: 10.1093/cid/ciae547.

The Burden of All-Cause Mortality Following Influenza-Associated Hospitalizations: Influenza Hospitalization Surveillance Network, 2010-2019

Alissa C O'Halloran  1 , Alexander J Millman  1 , Rachel Holstein  1 , Sonja J Olsen  1 , Charisse N Cummings  1 , Shua J Chai  2   3 , Pam Daily Kirley  2 , Nisha B Alden  4 , Kimberly Yousey-Hindes  5 , James Meek  5 , Kyle P Openo  6   7 , Emily Fawcett  6   7 , Patricia A Ryan  8 , Lauren Leegwater  9 , Justin Henderson  9 , Melissa McMahon  10 , Ruth Lynfield  10 , Kathy M Angeles  11 , Molly Bleecker  11 , Suzanne McGuire  12 , Nancy L Spina  12 , Brenda L Tesini  13 , Maria A Gaitan  13 , Krista Lung  14 , Eli Shiltz  14 , Ann Thomas  15 , H Keipp Talbot  16 , William Schaffner  16 , Mary Hill  17 , Carrie Reed  1 , Shikha Garg  1
Affiliations

The Burden of All-Cause Mortality Following Influenza-Associated Hospitalizations: Influenza Hospitalization Surveillance Network, 2010-2019

Alissa C O'Halloran et al. Clin Infect Dis. .

Abstract

Background: While the estimated number of US influenza-associated deaths is reported annually, detailed data on the epidemiology of influenza-associated deaths, including the burden of in-hospital vs post-hospital discharge deaths, are limited.

Methods: Using data from the 2010-2011 through 2018-2019 seasons from the Influenza Hospitalization Surveillance Network, we linked cases to death certificates to identify patients who died from any cause during their influenza hospital stay or within 30 days post discharge. We described demographic and clinical characteristics of patients who died in the hospital vs post discharge and characterized locations and causes of death (CODs).

Results: Among 121 390 cases hospitalized with laboratory-confirmed influenza over 9 seasons, 5.5% died; 76% of deaths were in patients aged ≥65 years, 71% were non-Hispanic White, and 34% had 4 or more underlying medical conditions. Among all patients with an influenza-associated hospitalization who died, 48% of deaths occurred after hospital discharge; the median number of days from discharge to death was 9 (interquartile range, 3-19). Post-discharge deaths more often occurred in older patients and among those with underlying medical conditions. Only 37% of patients who died had "influenza" as a COD on their death certificate. Influenza was more frequently listed as a COD among persons who died in the hospital compared with cardiovascular disease among those who died after discharge.

Conclusions: All-cause mortality burden is substantial among patients hospitalized with influenza, with almost 50% of deaths occurring within 30 days after hospital discharge. Surveillance systems should consider capture of post-discharge outcomes to better characterize the impact of influenza on all-cause mortality.

Keywords: cause of death; hospitalization; influenza; mortality; surveillance.

PubMed Disclaimer

Conflict of interest statement

Potential conflicts of interest . R. L. is associate editor for the American Academy of Pediatrics Report of the Committee on Infectious Diseases (Red Book) and was given a fee for this work, which was donated to Minnesota Department of Health. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed.

Figures

Figure 1.
Figure 1.
Mortality among laboratory-confirmed influenza-associated hospitalizations by season and age group, Influenza Hospitalization Surveillance Network (FluSurv-NET) 2010–2019. A, stratifies by season; B, stratifies by age group. Mortality includes those who died during hospitalization and those who died within 30 days after discharge among all FluSurv-NET cases. Denominators overall and by season: overall, n = 121 390; 2010–2011, n = 5663; 2011–2012, n = 2364; 2012–2013, n = 11 434; 2013–2014, n = 9658; 2014–2015, n = 17 743; 2015–2016, n = 8790; 2016–2017, n = 17 489; 2017–2018, n = 29 695; 2018–2019, n = 18 554.
Figure 2.
Figure 2.
Among patients with influenza-associated hospitalizations who died, the proportion of deaths that occurred during hospitalization vs within 30 days after hospital discharge by age group, Influenza Hospitalization Surveillance Network, 2010–2019.
Figure 3.
Figure 3.
Days from discharge to death among patients who died within 30 days after hospital discharge, Influenza Hospitalization Surveillance Network, 2010–2019 (n = 3215).
See this image and copyright information in PMC

References

    1. Centers for Disease Control and Prevention . Disease burden of flu. Available at: https://www.cdc.gov/flu-burden/php/about/index.html. Accessed 14 November 2024.
    1. Barker WH. Excess pneumonia and influenza associated hospitalization during influenza epidemics in the United States, 1970–78. Am J Public Health 1986; 76:761–5. - PMC - PubMed
    1. Barker WH, Mullooly JP. Impact of epidemic type A influenza in a defined adult population. Am J Epidemiol 1980; 112:798–811. - PubMed
    1. Coleman BL, Fadel SA, Fitzpatrick T, Thomas SM. Risk factors for serious outcomes associated with influenza illness in high- versus low- and middle-income countries: systematic literature review and meta-analysis. Influenza Other Respir Viruses 2018; 12:22–9. - PMC - PubMed
    1. Mullooly JP, Bridges CB, Thompson WW, et al. . Influenza- and RSV-associated hospitalizations among adults. Vaccine 2007; 25:846–55. - PubMed

Publication types