Risk of Severe Influenza among Adults with Chronic Medical Conditions

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J Infect Dis. 2019 Nov 4. pii: jiz570. doi: 10.1093/infdis/jiz570. [Epub ahead of print] Risk of Severe Influenza among Adults with Chronic Medical Conditions.

Walker TA¹, Waite B¹, Thompson MG², McArthur C³, Wong C⁴, Baker MG⁵, Wood T⁶, Haubrock J¹, Roberts S⁷, Gross DK², Huang QS¹, Newbern EC⁶.
Author information

1 WHO National Influenza Centre, Institute of Environmental Science and Research, New Zealand. 2 Influenza Division, Centers for Disease Control and Prevention, Atlanta, GeorgiaUSA. 3 Department of Critical Care Medicine, Auckland District Health Board, Greenlane, Auckland, New Zealand. 4 Department of Respiratory Medicine, Counties Manukau District Health Board, Papatoetoe, Auckland, New Zealand. 5 Department of Public Health, University of Otago, School of Medicine, Newtown, Wellington, New Zealand. 6 Health Intelligence Team, Institute of Environmental Science and Research, New Zealand. 7 Department of Microbiology, Auckland District Health Board, Greenlane, Auckland, New Zealand.

Abstract

BACKGROUND:

Severe influenza illness is presumed more common in adults with chronic medical conditions (CMC), but evidence is sparse and often combined into broad CMC categories.
METHODS:

Residents (aged 18-80 years) of Central and South Auckland hospitalized for WHO-defined severe acute respiratory illness (SARI) (2012-2015) underwent influenza virus PCR testing. CMC statuses for Auckland residents were modelled using hospitalization ICD-10 codes, pharmaceutical claims, and laboratory results. Population-level influenza rates in adults with congestive heart failure (CHF), coronary artery disease (CAD), cerebrovascular accidents (CVA), chronic obstructive pulmonary disease (COPD), asthma, diabetes mellitus (DM), and end-stage renal disease (ESRD) were calculated by Poisson regression stratified by age and adjusted for ethnicity.
RESULTS:

Among 891,276 adults, 2,435 influenza-associated SARI hospitalizations occurred. Rates were significantly higher in those with CMCs compared with those without the respective CMC except older adults with DM or those aged <65 years with CVA. The largest effects occurred with CHF (Incidence Rate Ratio [IRR] range: 4.84-13.4 across age strata), ESRD (IRR range: 3.30-9.02), CAD (IRR range= 2.77-10.7), and COPD (IRR range: 5.89-8.78) and tapered with age.
CONCLUSIONS:

Our findings support the increased risk of severe, laboratory-confirmed influenza disease among adults with specific CMCs compared those without these conditions.
? The Author(s) 2019. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.


KEYWORDS:

chronic medical conditions; influenza hospitalizations; influenza incidence; influenza risk

PMID: 31678990 DOI: 10.1093/infdis/jiz570