Hostname: page-component-8448b6f56d-sxzjt Total loading time: 0 Render date: 2024-04-23T23:22:45.563Z Has data issue: false hasContentIssue false

Influenza surveillance case definitions miss a substantial proportion of older adults hospitalized with laboratory-confirmed influenza: A report from the Canadian Immunization Research Network (CIRN) Serious Outcomes Surveillance (SOS) Network

Published online by Cambridge University Press:  09 March 2020

Melissa K. Andrew*
Affiliation:
Department of Medicine (Geriatrics), Dalhousie University, Halifax, Nova Scotia, Canada Canadian Center for Vaccinology, IWK Health Centre and Nova Scotia Health Authority, Dalhousie University, Halifax, Nova Scotia, Canada
Janet E. McElhaney
Affiliation:
Health Sciences North Research Institute, Sudbury, Ontario, Canada
Allison A. McGeer
Affiliation:
Mount Sinai Hospital, Toronto, Ontario, Canada
Todd F. Hatchette
Affiliation:
Department of Medicine (Geriatrics), Dalhousie University, Halifax, Nova Scotia, Canada Canadian Center for Vaccinology, IWK Health Centre and Nova Scotia Health Authority, Dalhousie University, Halifax, Nova Scotia, Canada
Jason Leblanc
Affiliation:
Canadian Center for Vaccinology, IWK Health Centre and Nova Scotia Health Authority, Dalhousie University, Halifax, Nova Scotia, Canada Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada
Duncan Webster
Affiliation:
Saint John Regional Hospital, Dalhousie University, Saint John, New Brunswick, Canada
William Bowie
Affiliation:
Division of Infectious Diseases, University of British Columbia, Vancouver, British Columbia, Canada
Andre Poirier
Affiliation:
Centre Intégré Universitaire de santé et services sociaux, Quebec, Quebec, Canada
Michaela K. Nichols
Affiliation:
Canadian Center for Vaccinology, IWK Health Centre and Nova Scotia Health Authority, Dalhousie University, Halifax, Nova Scotia, Canada
Shelly A. McNeil
Affiliation:
Department of Medicine (Geriatrics), Dalhousie University, Halifax, Nova Scotia, Canada Canadian Center for Vaccinology, IWK Health Centre and Nova Scotia Health Authority, Dalhousie University, Halifax, Nova Scotia, Canada
*
Author for correspondence: Melissa K. Andrew, MD, PhD, E-mail: mandrew@dal.ca

Abstract

Objective:

Older adults often have atypical presentation of illness and are particularly vulnerable to influenza and its sequelae, making the validity of influenza case definitions particularly relevant. We sought to assess the performance of influenza-like illness (ILI) and severe acute respiratory illness (SARI) criteria in hospitalized older adults.

Design:

Prospective cohort study.

Setting:

The Serious Outcomes Surveillance Network of the Canadian Immunization Research Network undertakes active surveillance for influenza among hospitalized adults.

Methods:

Data were pooled from 3 influenza seasons: 2011/12, 2012/13, and 2013/14. The ILI and SARI criteria were defined clinically, and influenza was laboratory confirmed. Frailty was measured using a validated frailty index.

Results:

Of 11,379 adult inpatients (7,254 aged ≥65 years), 4,942 (2,948 aged ≥65 years) had laboratory-confirmed influenza. Their median age was 72 years (interquartile range [IQR], 58–82) and 52.6% were women. The sensitivity of ILI criteria was 51.1% (95% confidence interval [CI], 49.6–52.6) for younger adults versus 44.6% (95% CI, 43.6–45.8) for older adults. SARI criteria were met by 64.1% (95% CI, 62.7–65.6) of younger adults versus 57.1% (95% CI, 55.9–58.2) of older adults with laboratory-confirmed influenza. Patients with influenza who were prefrail or frail were less likely to meet ILI and SARI case definitions.

Conclusions:

A substantial proportion of older adults, particularly those who are frail, are missed by standard ILI and SARI case definitions. Surveillance using these case definitions is biased toward identifying younger cases, and does not capture the true burden of influenza. Because of the substantial fraction of cases missed, surveillance definitions should not be used to guide diagnosis and clinical management of influenza.

Type
Original Article
Copyright
© 2020 by The Society for Healthcare Epidemiology of America. All rights reserved

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Footnotes

PREVIOUS PRESENTATION: An earlier version of this work was presented as an oral abstract at the Canadian Immunization Conference, on December 6, 2018, in Ottawa, Ontario, Canada.

References

WHO surveillance case definitions for ILI and SARI. World Health Organization website. http://www.who.int/influenza/surveillance_monitoring/ili_sari_surveillance_case_definition/en/. Published 2014. Accessed February 3, 2020.Google Scholar
Fitzner, J, Qasmieh, S, Mounts, AW, et al. Revision of clinical case definitions: influenza-like illness and severe acute respiratory infection. Bull WHO 2018;96:122128.Google ScholarPubMed
Jarrett, PG, Rockwood, K, Carver, D, Stolee, P, Cosway, S. Illness presentation in elderly patients. Arch Intern Med 1995;155:10601064.CrossRefGoogle ScholarPubMed
Rockwood, K. Medical management of frailty: confessions of a gnostic. CMAJ 1997;157:10811084.Google ScholarPubMed
Andrew, MK, Shinde, V, Hatchette, T, et al. Influenza vaccine effectiveness against influenza-related hospitalization during a season with mixed outbreaks of four influenza viruses: a test-negative case-control study in adults in Canada. BMC Infect Dis 2017;17:805.CrossRefGoogle ScholarPubMed
Andrew, MK, Shinde, V, Ye, L, et al. The importance of frailty in the assessment of influenza vaccine effectiveness against influenza-related hospitalization in elderly people. J Infect Dis 2017;216:405414.CrossRefGoogle ScholarPubMed
McNeil, S, Shinde, V, Andrew, M, et al. Interim estimates of 2013/14 influenza clinical severity and vaccine effectiveness in the prevention of laboratory-confirmed influenza-related hospitalisation, Canada, February 2014. Euro Surveill 2014;19(9): pii: 20729.CrossRefGoogle Scholar
McNeil, SA, Andrew, MK, Ye, L, et al. Interim estimates of 2014/15 influenza vaccine effectiveness in preventing laboratory-confirmed influenza-related hospitalisation from the Serious Outcomes Surveillance Network of the Canadian Immunization Research Network, January 2015. Euro Surveill 2015;20:21024.CrossRefGoogle Scholar
Nichols, MK, Andrew, MK, Hatchette, TF, et al. Influenza vaccine effectiveness to prevent influenza-related hospitalizations and serious outcomes in Canadian adults over the 2011/12 through 2013/14 influenza seasons: a pooled analysis from the Canadian Immunization Research Network (CIRN) Serious Outcomes Surveillance (SOS Network). Vaccine 2018;36:21662175.CrossRefGoogle Scholar
Hoover, M, Rotermann, M, Sanmartin, C, Bernier, J. Validation of an index to estimate the prevalence of frailty among community-dwelling seniors. Health Rept 2013;24(9):1017.Google ScholarPubMed
Hartman, L, Zhu, Y, Edwards, KM, Griffin, MR, Talbot, HK. Underdiagnosis of influenza virus infection in hospitalized older adults. J Am Geriatr Soc 2018;66:467472.CrossRefGoogle ScholarPubMed
Jiang, L, Lee, VJ, Lim, WY, et al. Performance of case definitions for influenza surveillance. Euro Surveill 2015;20:21145.CrossRefGoogle ScholarPubMed
Claus, JA, Hodowanec, AC, Singh, K. Poor positive predictive value of influenza-like illness criteria in adult transplant patients: a case for multiplex respiratory virus PCR testing. Clin Transplant 2015;29:938943.CrossRefGoogle ScholarPubMed
Dai, XQ, Liu, M, Zhang, TH, et al. Clinical predictors for diagnosing pandemic (H1N1) 2009 and seasonal influenza (H3N2) in fever clinics in Beijing, China. Biomed Environ Sci 2012;25:6168.Google ScholarPubMed
Chen, SY, Chen, YC, Chiang, WC, et al. Field performance of clinical case definitions for influenza screening during the 2009 pandemic. Am J Emerg Med 2012;30:17961803.CrossRefGoogle ScholarPubMed
Rumoro, DP, Bayram, JD, Silva, JC, et al. The impact of alternative diagnoses on the utility of influenza-like illness case definition to detect the 2009 H1N1 pandemic. Am J Disaster Med 2012;7:105110.CrossRefGoogle ScholarPubMed
Casalegno, JS, Eibach, D, Valette, M, et al. Performance of influenza case definitions for influenza community surveillance: based on the French influenza surveillance network GROG, 2009–2014. Euro Surveill 2017;22(14): pii: 30504. doi: 10.2807/1560-7917.CrossRefGoogle ScholarPubMed
Carrat, F, Tachet, A, Rouzioux, C, Housset, B, Valleron, AJ. Evaluation of clinical case definitions of influenza: detailed investigation of patients during the 1995–1996 epidemic in France. Clin Infect Dis 1999;28:283290.CrossRefGoogle ScholarPubMed
Shah, SC, Rumoro, DP, Hallock, MM, et al. Clinical predictors for laboratory-confirmed influenza infections: exploring case definitions for influenza-like illness. Infect Control Hosp Epidemiol 2015;36:241248.CrossRefGoogle ScholarPubMed
Lam, PP, Coleman, BL, Green, K, et al. Predictors of influenza among older adults in the emergency department. BMC Infect Dis 2016;16:615.CrossRefGoogle ScholarPubMed
Yang, TU, Cheong, HJ, Song, JY, et al. Age- and influenza activity-stratified case definitions of influenza-like illness: experience from hospital-based influenza surveillance in South Korea. PLoS One 2014;9(1):e84873.CrossRefGoogle ScholarPubMed
Mosnier, A, Daviaud, I, Caini, S, et al. Does seasonal vaccination affect the clinical presentation of influenza among the elderly? A cross-sectional analysis in the outpatient setting in France, 2003–2014. Vaccine 2017;35:20762083.CrossRefGoogle Scholar
Murray, EL, Khagayi, S, Ope, M, et al. What are the most sensitive and specific sign and symptom combinations for influenza in patients hospitalized with acute respiratory illness? Results from western Kenya, January 2007–July 2010. Epidemiol Infect 2013;141:212222.CrossRefGoogle Scholar
Arriola, C, Garg, S, Anderson, EJ, et al. Influenza vaccination modifies disease severity among community-dwelling adults hospitalized with influenza. Clin Infect Dis 2017;65:12891297.CrossRefGoogle ScholarPubMed
Thompson, MG, Pierse, N, Sue Huang, Q, et al. Influenza vaccine effectiveness in preventing influenza-associated intensive care admissions and attenuating severe disease among adults in New Zealand 2012–2015. Vaccine 2018;36:59165925.CrossRefGoogle ScholarPubMed
Andrew, MK. Social vulnerability in old age. In: Fillit, HM, Rockwood, K, Young, J, eds. Brocklehurst’s Textbook of Geriatric Medicine and Gerontology. Eighth ed. Philadelphia: Elsevier; 2016:185192.Google Scholar
Falsey, AR, Baran, A, Walsh, EE. Should clinical case definitions of influenza in hospitalized older adults include fever? Influenza Other Respir Viruses 2015;9 suppl 1:2329.CrossRefGoogle ScholarPubMed
High, KP, Bradley, SF, Gravenstein, S, et al. Clinical practice guideline for the evaluation of fever and infection in older adult residents of long-term care facilities: 2008 update by the Infectious Diseases Society of America. Clin Infect Dis 2009;48:149171.CrossRefGoogle ScholarPubMed
Stone, ND, Ashraf, MS, Calder, J, et al. Surveillance definitions of infections in long-term care facilities: revisiting the McGeer criteria. Infect Control Hosp Epidemiol 2012;33:965977.CrossRefGoogle ScholarPubMed