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
. 2019 Jul 1;6(7):ofz225.
doi: 10.1093/ofid/ofz225.

Age-Related Differences in Hospitalization Rates, Clinical Presentation, and Outcomes Among Older Adults Hospitalized With Influenza-U.S. Influenza Hospitalization Surveillance Network (FluSurv-NET)

Christopher A Czaja  1   2 , Lisa Miller  2 , Nisha Alden  1 , Heidi L Wald  3 , Charisse Nitura Cummings  4 , Melissa A Rolfes  4 , Evan J Anderson  5 , Nancy M Bennett  6 , Laurie M Billing  7 , Shua J Chai  4   8 , Seth Eckel  9 , Robert Mansmann  10 , Melissa McMahon  11 , Maya L Monroe  12 , Alison Muse  13 , Ilene Risk  14 , William Schaffner  15 , Ann R Thomas  16 , Kimberly Yousey-Hindes  17 , Shikha Garg  4 , Rachel K Herlihy  1
Affiliations

Age-Related Differences in Hospitalization Rates, Clinical Presentation, and Outcomes Among Older Adults Hospitalized With Influenza-U.S. Influenza Hospitalization Surveillance Network (FluSurv-NET)

Christopher A Czaja et al. Open Forum Infect Dis. .

Abstract

Background: Rates of influenza hospitalizations differ by age, but few data are available regarding differences in laboratory-confirmed rates among adults aged ≥65 years.

Methods: We evaluated age-related differences in influenza-associated hospitalization rates, clinical presentation, and outcomes among 19 760 older adults with laboratory-confirmed influenza at 14 FluSurv-NET sites during the 2011-2012 through 2014-2015 influenza seasons using 10-year age groups.

Results: There were large stepwise increases in the population rates of influenza hospitalization with each 10-year increase in age. Rates ranged from 101-417, 209-1264, and 562-2651 per 100 000 persons over 4 influenza seasons in patients aged 65-74 years, 75-84 years, and ≥85 years, respectively. Hospitalization rates among adults aged 75-84 years and ≥85 years were 1.4-3.0 and 2.2-6.4 times greater, respectively, than rates for adults aged 65-74 years. Among patients hospitalized with laboratory-confirmed influenza, there were age-related differences in demographics, medical histories, and symptoms and signs at presentation. Compared to hospitalized patients aged 65-74 years, patients aged ≥85 years had higher odds of pneumonia (aOR, 1.2; 95% CI, 1.0-1.3; P = .01) and in-hospital death or transfer to hospice (aOR, 2.1; 95% CI, 1.7-2.6; P < .01).

Conclusions: Age-related differences in the incidence and severity of influenza hospitalizations among adults aged ≥65 years can inform prevention and treatment efforts, and data should be analyzed and reported using additional age strata.

Keywords: adult; epidemiology; hospitalization; human; influenza.

PubMed Disclaimer

Figures

Figure 1.
Figure 1.
Estimated population rates of influenza-associated hospitalization with 95% confidence intervals by influenza season and age group—U.S Influenza Hospitalization Surveillance Network (FluSurv-NET). Influenza A(H3N2) was the predominant circulating virus during the 2011–2012, 2012–2013, and 2014–2015 seasons. Influenza A(H1N1) predominated during the 2013–2014 season.
See this image and copyright information in PMC

References

    1. Centers for Disease Control and Prevention. Estimates of deaths associated with seasonal influenza — United States, 1976–2007. MMWR Morb Mortal Wkly Rep 2010; 59:1057–62. - PubMed
    1. Zhou H, Thompson WW, Viboud CG, et al. . Hospitalizations associated with influenza and respiratory syncytial virus in the United States, 1993–2008. Clin Infect Dis 2012; 54:1427–36. - PMC - PubMed
    1. Reed C, Chaves SS, Daily Kirley P, et al. . Estimating influenza disease burden from population-based surveillance data in the United States. PLOS ONE 2015; 10:e0118369. - PMC - PubMed
    1. Quandelacy TM, Viboud C, Charu V, et al. . Age- and sex-related risk factors for influenza-associated mortality in the United States between 1997–2007. Am J Epidemiol 2014; 179:156–67. - PMC - PubMed
    1. Mertz D, Kim TH, Johnstone J, et al. . Populations at risk for severe or complicated influenza illness: systematic review and meta-analysis. BMJ 2013; 347:f5061. - PMC - PubMed