2498. Association of Increasing Age with Hospitalization Rates, Clinical Presentation, and Outcomes among Older Adults Hospitalized with Influenza—U.S. Influenza Hospitalization Surveillance Network (FluSurv-NET)
Session: Poster Abstract Session: Virology Potpourri
Saturday, October 6, 2018
Room: S Poster Hall
  • FOA_IDweek_poster_091718.pdf (237.1 kB)
  • Background: Few data describe the epidemiology of influenza among adults ≥65 years old according to age strata. We evaluated age-related differences in influenza-associated hospitalization rates, clinical presentation, and outcomes among older adults at 14 FluSurv-NET sites during the 2011-12 through 2014-15 influenza seasons.

    Methods: Study patients were hospitalized ≤14 days after and ≤3 days before a positive influenza test. Age strata were 65-74, 75-84, and ≥85 years old. We adjusted hospitalization rates for under detection and assessed for age-related trends in risk factors and symptoms. We used logistic regression to calculate odds ratios (OR) for pneumonia and in-hospital death adjusted for season, sex, nursing home residence, smoking, medical comorbidities, influenza vaccination, and study site.

    Results: There were 19,760 patients, including 5,956 aged 65-74 years, 6,998 aged 75-84 years, and 6,806 aged ≥85 years. There was a stepwise increase in hospitalization rates with age (Figure). Increasing age was positively associated with female sex, nursing home residence, neurologic disorder, cardiovascular and renal disease, and vaccination, and inversely associated with morbid obesity, smoking, asthma, chronic metabolic disease, and immunosuppression (p<0.01). Among 10,548 (53.3%) patients with symptom data from 2014-15, increasing age was associated with a higher prevalence of altered mental status and lower prevalence of fever, myalgias, respiratory or gastrointestinal symptoms, and headache (p≤0.01). Compared to 65-74 year-olds, older patients had a higher risk of pneumonia (≥85 year-olds: OR 1.2, 95% CI 1.0, 1.3, p=0.01) and death (75-84 year-olds: OR 1.4, 95% CI 1.2, 1.7, p<0.01; ≥85 year-olds: OR 2.1, 95% CI 1.7, 2.6, p<0.01).

    Conclusion: There are age-related differences in the epidemiology, clinical presentation, and outcomes of older adults hospitalized with influenza. These may reflect differences in health status and healthcare provider practice patterns. Public health epidemiologists should consider using additional age strata in ≥65 year-olds when analyzing influenza surveillance data. Clinicians should be aware that influenza among the oldest adults may present atypically and that mortality is increased.

    The SGPlot Procedure

    Christopher Czaja, MD MPH1,2, Lisa Miller, MD, MSPH3, Nisha Alden, MPH2, Heidi Wald, MD, MSPH4, Charisse Nitura Cummings, MPH5, Melissa Rolfes, PhD, MPH5, Shikha Garg, MD, MPH5, Evan J. Anderson, MD6,7, Nancy M. Bennett, MD, MS8, Laurie Billing, MPH9, Shua J Chai, MD MPH10, Seth Eckel, MPH11, Robert Mansmann, MPH12, Melissa McMahon, MPH13, Maya Monroe, MPH14, Alison Muse, MPH15, Ilene Risk, MPA16, William Schaffner, MD, FIDSA, FSHEA17, Ann Thomas, MD, MPH18, Kimberly Yousey-Hindes, MPH, CPH19 and Rachel Herlihy, MD MPH2, (1)Epidemiology, Colorado School of Public Health, Aurora, CO, (2)Colorado Department of Public Health and Environment, Denver, CO, (3)Preventive Medicine Residency Program, University of Colorado School of Public Health, Aurora, CO, (4)SCL Health, Broomfield, CO, (5)Influenza Division, Centers for Disease Control and Prevention, Atlanta, GA, (6)Georgia Emerging Infections Program (EIP), Atlanta, GA, (7)Pediatrics and Medicine, Emory University School of Medicine, Atlanta, GA, (8)University of Rochester School of Medicine and Dentistry, Rochester, NY, (9)Ohio Department of Health, Columbus, OH, (10)California Department of Public Health, Oakland, CA, (11)Communicable Disease Division, Michigan Department of Health and Human Services, Lansing, MI, (12)New Mexico Emerging Infections Program, Albuquerque, NM, (13)Minnesota Department of Health, St. Paul, MN, (14)Maryland Department of Health and Mental Hygiene, Baltimore, MD, (15)New York State Department of Health, Albany, NY, (16)Salt Lake County Health Department, Salt Lake City, UT, (17)Vanderbilt University School of Medicine, Nashville, TN, (18)Oregon Public Health Division, Portland, OR, (19)Connecticut Emerging Infections Program, Yale School of Public Health, New Haven, CT


    C. Czaja, None

    L. Miller, None

    N. Alden, None

    H. Wald, None

    C. Nitura Cummings, None

    M. Rolfes, None

    S. Garg, None

    E. J. Anderson, NovaVax: Grant Investigator , Research grant . Pfizer: Grant Investigator , Research grant . AbbVie: Consultant , Consulting fee . MedImmune: Investigator , Research support . PaxVax: Investigator , Research support . Micron: Investigator , Research support .

    N. M. Bennett, None

    L. Billing, None

    S. J. Chai, None

    S. Eckel, None

    R. Mansmann, None

    M. McMahon, None

    M. Monroe, None

    A. Muse, None

    I. Risk, None

    W. Schaffner, Merck: Member, Data Safety Monitoring Board , Consulting fee . Pfizer: Member, Data Safety Monitoring Board , Consulting fee . Dynavax: Consultant , Consulting fee . Seqirus: Consultant , Consulting fee . SutroVax: Consultant , Consulting fee . Shionogi: Consultant , Consulting fee .

    A. Thomas, None

    K. Yousey-Hindes, None

    R. Herlihy, None

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