710. Impact of Frailty on Influenza Vaccine Effectiveness and Clinical Outcomes: Experience from the Canadian Immunization Research Network (CIRN) Serious Outcomes Surveillance (SOS) Network 2011/12 Season
Session: Poster Abstract Session: Vaccines
Thursday, October 27, 2016
Room: Poster Hall
  • Andrews.Frailty ID Week2016 Final.pdf (370.0 kB)
  • Background:  Health impact of influenza is traditionally considered only in acute terms. There is increasing evidence that influenza may have lasting health implications, particularly for frail older adults. We studied vaccine effectiveness (VE) and outcomes of influenza-related hospitalization in relation to frailty & functional status.

    Methods:  The SOS Network conducted active surveillance for influenza in Canadian hospitals for the 2011/12 influenza season. VE for prevention of influenza-hospitalization was assessed using a matched test-negative case-control analysis. Special attention was paid to frailty & functional status of patients ≥65y at baseline (2 weeks prior to onset of symptoms) and follow up (30d post-discharge). Admission swabs were tested by PCR to identify influenza cases (positive) and controls (negative). VE was calculated as 1 minus the odds ratio of vaccination in cases versus controls x 100. VE estimates were adjusted using conditional multivariate logistic regression with age, antiviral use, frailty and a stepwise backward selection of covariates with p-values of <0.1 by univariate analysis. Frailty was assessed using a validated 39-item frailty index (FI) & function was assessed using the Barthel Index (BI).

    Results:  SOS enrolled 320 cases & 564 controls. Unadjusted VE for patients ≥65y against influenza-hospitalization due to any strain was 45.0% (95% CI: 25.7, 59.3); adjusted VE was 58.0% (95% CI: 34.2, 73.2). Adjusting for frailty on top of fixed covariates alone very closely approximated the final fully adjusted model. On average, all older adults experienced functional loss during hospitalization. 15.1% experienced persistent catastrophic disability (≥20 point decline on the BI between baseline & follow up); older patients with influenza were more likely to experience this decline than controls in the same age segment (p=0.047).

    Conclusion:  VE was moderate for prevention of influenza-related hospitalization in elderly people. Not accounting for frailty may underestimate VE due to a frailty bias; frailty is the most important confounder to take into account in adults 65+. Persistent functional decline is an important adverse outcome of influenza-related hospitalization and reducing this burden represents an important public health goal.

    Melissa K Andrew, MD, PhD1, Sarah Macdonald, BSc1, Lingyun Ye, PhD1, Ardith Ambrose, RN1, Guy Boivin, MD, MSc2, Francisco Diaz-Mitoma, MD, PhD3, William Bowie, MD, FRCPC, FIDSA4, Ayman Chit, MBiotech, PhD5, Gael Dos Santos, PhD6, May Elsherif, MD1, Karen Green, MSc7, Todd Hatchette, MD1, Francois Haguinet, PhD8, Scott a. Halperin, MD1, Barbara Ibarguchi, MSc9, Jennie Johnstone, MD10, Kevin Katz, MD, CM, MSc, FRCPC11, Philippe Lagace-Wiens, MD12, Joanne M. Langley, MD, FRCPC, FSHEA1, Jason Leblanc, PhD1, Bruce Light, MD12, Mark Loeb, MD, MSc10, Donna Mackinnon-Cameron, MMath1, Anne E. Mccarthy, MD13, Janet E. Mcelhaney, MD3, Allison Mcgeer, MD, MSc7, Andre Poirier, MD, MSc14, Jeff Powis, MD, MSc, FRCPC15, David Richardson, MD16, Makeda Semret, MD17, Vivek Shinde, MD, MPH18, Stephanie Smith, MD, MSc19, Daniel Smyth, MD, FRCPC20, Grant Stiver, MD4, Geoffrey Taylor, MD, FSHEA19, Sylvie Trottier, MD2, Louis Valiquette, MD, MSc21, Duncan Webster, MD22, Shelly a Mcneil, MD, FRCPC, FIDSA1 and on behalf of the CIRN SOS Network Investigators and the TIBDN Investigators, (1)Canadian Center for Vaccinology, IWK Health Centre and Nova Scotia Health Authority, Dalhousie University, Halifax, NS, Canada, (2)Centre Hospitalier Universitaire de Quebec, Quebec, QC, Canada, (3)Health Sciences North Research Institute of Canada, Sudbury, ON, Canada, (4)University of British Columbia, Vancouver, BC, Canada, (5)Leslie Dan Faculty of Pharmacy, Toronto, ON, Canada, (6)Business & Decision Life Sciences (on behalf of GSK Vaccines), Wavre, Belgium, (7)Mount Sinai Hospital, Toronto, ON, Canada, (8)GSK Vaccines, Wavre, Belgium, (9)GSK Vaccines (Current affiliation Bayer Inc.), Mississauga, ON, Canada, (10)McMaster University, Hamilton, ON, Canada, (11)North York General Hospital, Toronto, ON, Canada, (12)St. Boniface Hospital, Winnipeg, MB, Canada, (13)The Ottawa Hospital, Ottawa, ON, Canada, (14)Centre integre de sante et de services sociaux de la Maurice centre du Quebec, Trois-Rivieres, QC, Canada, (15)Toronto East General Hospital, Toronto, ON, Canada, (16)William Osler Health Centre, Brampton, ON, Canada, (17)McGill University, Montreal, QC, Canada, (18)GSK Vaccines (Current affiliation Novavax Vaccines, Washington, DC, USA), King of Prussia, PA, (19)University of Alberta, Edmonton, AB, Canada, (20)The Moncton Hospital, Moncton, NB, Canada, (21)Universite de Sherbrooke, Sherbrooke, QC, Canada, (22)Horizon Health, St. John, NB, Canada


    M. K. Andrew, GSK: Investigator , Research support

    S. Macdonald, None

    L. Ye, None

    A. Ambrose, None

    G. Boivin, Biocryst: Investigator , Research grant
    Merck: Investigator , Research grant

    F. Diaz-Mitoma, None

    W. Bowie, GSK: Investigator , Research grant

    A. Chit, Sanofi Pasteur: Employee , Salary

    G. Dos Santos, Business and Decision Life Sciences: Consultant , Salary

    M. Elsherif, None

    K. Green, None

    T. Hatchette, GSK: Investigator , Research grant

    F. Haguinet, GSK Vaccines: Employee , Salary

    S. A. Halperin, GSK: Consultant , Grant Investigator and Research Contractor , Consulting fee and Grant recipient

    B. Ibarguchi, GSK: Employee , Salary

    J. Johnstone, None

    K. Katz, None

    P. Lagace-Wiens, Merck: Scientific Advisor , Consulting fee and Speaker honorarium

    J. M. Langley, Sanofi Pasteur: Investigator , Research grant
    GSK: Investigator , Research grant
    PREVENT: Investigator , Research grant

    J. Leblanc, None

    B. Light, None

    M. Loeb, None

    D. Mackinnon-Cameron, None

    A. E. Mccarthy, GSK: Investigator , Research support

    J. E. Mcelhaney, GSK: Scientific Advisor , Research support and Speaker honorarium
    Sanofi Pasteur: Scientific Advisor , Speaker honorarium

    A. Mcgeer, None

    A. Poirier, Actelion: Investigator , Research grant
    Genetech: Investigator , Research grant
    Sanofi Pasteur: Investigator , Research grant
    Vertex: Investigator , Research grant

    J. Powis, GSK: Investigator , Research support

    D. Richardson, None

    M. Semret, None

    V. Shinde, GSK: Employee , Salary

    S. Smith, None

    D. Smyth, None

    G. Stiver, None

    G. Taylor, None

    S. Trottier, None

    L. Valiquette, None

    D. Webster, None

    S. A. Mcneil, GSK: Grant Investigator , Research grant and Research support
    Pfizer: Grant Investigator , Consulting fee , Research grant , Research support and Speaker honorarium
    Merck: Consultant and Investigator , Consulting fee , Research support and Speaker honorarium

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