Comparison of the Outcomes of Individuals With Medically Attended Influenza A and B Virus Infections Enrolled in 2 International Cohort Studies Over a 6-Year Period: 2009-2015

Dominic E Dwyer; Ruth Lynfield; Marcelo H Losso; Richard T Davey; Alessandro Cozzi-Lepri; Deborah Wentworth; Timothy M Uyeki; Fred Gordin; Brian Angus; Tavs Qvist; Sean Emery; Jens Lundgren; James D Neaton; INSIGHT Influenza Study Group

doi:10.1093/ofid/ofx212

Comparison of the Outcomes of Individuals With Medically Attended Influenza A and B Virus Infections Enrolled in 2 International Cohort Studies Over a 6-Year Period: 2009-2015

Dominic E Dwyer, Ruth Lynfield, Marcelo H Losso, Richard T Davey, Alessandro Cozzi-Lepri, Deborah Wentworth, Timothy M Uyeki, Fred Gordin, Brian Angus, Tavs Qvist, Sean Emery, Jens Lundgren, James D Neaton, INSIGHT Influenza Study Group

Department of Clinical Medicine

9 Citations (Scopus)

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Abstract

Background. Outcome data from prospective follow-up studies comparing infections with different influenza virus types/subtypes are limited. Methods. Demographic, clinical characteristics and follow-up outcomes for adults with laboratory-confirmed influenza A(H1N1)pdm09, A(H3N2), or B virus infections were compared in 2 prospective cohorts enrolled globally from 2009 through 2015. Logistic regression was used to compare outcomes among influenza virus type/subtypes. Results. Of 3952 outpatients, 1290 (32.6%) had A(H1N1)pdm09 virus infection, 1857 (47.0%) had A(H3N2), and 805 (20.4%) had influenza B. Of 1398 inpatients, 641 (45.8%) had A(H1N1)pdm09, 532 (38.1%) had A(H3N2), and 225 (16.1%) had influenza B. Outpatients with A(H1N1)pdm09 were younger with fewer comorbidities and were more likely to be hospitalized during the 14-day follow-up (3.3%) than influenza B (2.2%) or A(H3N2) (0.7%; P < .0001). Hospitalized patients with A(H1N1)pdm09 (20.3%) were more likely to be enrolled from intensive care units (ICUs) than those with A(H3N2) (11.3%) or B (9.8%; P < .0001). However, 60-day follow-up of discharged inpatients showed no difference in disease progression (P = .32) or all-cause mortality (P = .30) among influenza types/subtypes. These findings were consistent after covariate adjustment, in sensitivity analyses, and for subgroups defined by age, enrollment location, and comorbidities. Conclusions. Outpatients infected with influenza A(H1N1)pdm09 or influenza B were more likely to be hospitalized than those with A(H3N2). Hospitalized patients infected with A(H1N1)pdm09 were younger and more likely to have severe disease at study entry (measured by ICU enrollment), but did not have worse 60-day outcomes.

Original language	English
Article number	ofx212
Journal	Open Forum Infectious Diseases
Volume	4
Issue number	4
Number of pages	8
ISSN	2328-8957
DOIs	https://doi.org/10.1093/ofid/ofx212
Publication status	Published - 2020

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Comparison of the Outcomes of Individuals With Medically Attended Influenza A and B Virus Infections Enrolled in 2 International Cohort Studies Over a 6-Year Period: 2009–2015Final published version, 162 KBLicence: CC BY

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Dwyer, D. E., Lynfield, R., Losso, M. H., Davey, R. T., Cozzi-Lepri, A., Wentworth, D., Uyeki, T. M., Gordin, F., Angus, B., Qvist, T., Emery, S., Lundgren, J., Neaton, J. D., & INSIGHT Influenza Study Group (2020). Comparison of the Outcomes of Individuals With Medically Attended Influenza A and B Virus Infections Enrolled in 2 International Cohort Studies Over a 6-Year Period: 2009-2015. Open Forum Infectious Diseases, 4(4), [ofx212]. https://doi.org/10.1093/ofid/ofx212

Comparison of the Outcomes of Individuals With Medically Attended Influenza A and B Virus Infections Enrolled in 2 International Cohort Studies Over a 6-Year Period : 2009-2015. / Dwyer, Dominic E; Lynfield, Ruth; Losso, Marcelo H et al.

In: Open Forum Infectious Diseases, Vol. 4, No. 4, ofx212, 2020.

Research output: Contribution to journal › Journal article › Research › peer-review

Dwyer, DE, Lynfield, R, Losso, MH, Davey, RT, Cozzi-Lepri, A, Wentworth, D, Uyeki, TM, Gordin, F, Angus, B, Qvist, T, Emery, S, Lundgren, J, Neaton, JD & INSIGHT Influenza Study Group 2020, 'Comparison of the Outcomes of Individuals With Medically Attended Influenza A and B Virus Infections Enrolled in 2 International Cohort Studies Over a 6-Year Period: 2009-2015', Open Forum Infectious Diseases, vol. 4, no. 4, ofx212. https://doi.org/10.1093/ofid/ofx212

@article{4bb90223d6c44796ba5684281e6f0998,

title = "Comparison of the Outcomes of Individuals With Medically Attended Influenza A and B Virus Infections Enrolled in 2 International Cohort Studies Over a 6-Year Period: 2009-2015",

abstract = "Background. Outcome data from prospective follow-up studies comparing infections with different influenza virus types/subtypes are limited. Methods. Demographic, clinical characteristics and follow-up outcomes for adults with laboratory-confirmed influenza A(H1N1)pdm09, A(H3N2), or B virus infections were compared in 2 prospective cohorts enrolled globally from 2009 through 2015. Logistic regression was used to compare outcomes among influenza virus type/subtypes. Results. Of 3952 outpatients, 1290 (32.6%) had A(H1N1)pdm09 virus infection, 1857 (47.0%) had A(H3N2), and 805 (20.4%) had influenza B. Of 1398 inpatients, 641 (45.8%) had A(H1N1)pdm09, 532 (38.1%) had A(H3N2), and 225 (16.1%) had influenza B. Outpatients with A(H1N1)pdm09 were younger with fewer comorbidities and were more likely to be hospitalized during the 14-day follow-up (3.3%) than influenza B (2.2%) or A(H3N2) (0.7%; P < .0001). Hospitalized patients with A(H1N1)pdm09 (20.3%) were more likely to be enrolled from intensive care units (ICUs) than those with A(H3N2) (11.3%) or B (9.8%; P < .0001). However, 60-day follow-up of discharged inpatients showed no difference in disease progression (P = .32) or all-cause mortality (P = .30) among influenza types/subtypes. These findings were consistent after covariate adjustment, in sensitivity analyses, and for subgroups defined by age, enrollment location, and comorbidities. Conclusions. Outpatients infected with influenza A(H1N1)pdm09 or influenza B were more likely to be hospitalized than those with A(H3N2). Hospitalized patients infected with A(H1N1)pdm09 were younger and more likely to have severe disease at study entry (measured by ICU enrollment), but did not have worse 60-day outcomes. ",

author = "Dwyer, {Dominic E} and Ruth Lynfield and Losso, {Marcelo H} and Davey, {Richard T} and Alessandro Cozzi-Lepri and Deborah Wentworth and Uyeki, {Timothy M} and Fred Gordin and Brian Angus and Tavs Qvist and Sean Emery and Jens Lundgren and Neaton, {James D} and {INSIGHT Influenza Study Group}",

year = "2020",

doi = "10.1093/ofid/ofx212",

language = "English",

volume = "4",

journal = "Open Forum Infectious Diseases",

issn = "2328-8957",

publisher = "Oxford University Press",

number = "4",

}

TY - JOUR

T1 - Comparison of the Outcomes of Individuals With Medically Attended Influenza A and B Virus Infections Enrolled in 2 International Cohort Studies Over a 6-Year Period

T2 - 2009-2015

AU - Dwyer, Dominic E

AU - Lynfield, Ruth

AU - Losso, Marcelo H

AU - Davey, Richard T

AU - Cozzi-Lepri, Alessandro

AU - Wentworth, Deborah

AU - Uyeki, Timothy M

AU - Gordin, Fred

AU - Angus, Brian

AU - Qvist, Tavs

AU - Emery, Sean

AU - Lundgren, Jens

AU - Neaton, James D

AU - INSIGHT Influenza Study Group

PY - 2020

Y1 - 2020

N2 - Background. Outcome data from prospective follow-up studies comparing infections with different influenza virus types/subtypes are limited. Methods. Demographic, clinical characteristics and follow-up outcomes for adults with laboratory-confirmed influenza A(H1N1)pdm09, A(H3N2), or B virus infections were compared in 2 prospective cohorts enrolled globally from 2009 through 2015. Logistic regression was used to compare outcomes among influenza virus type/subtypes. Results. Of 3952 outpatients, 1290 (32.6%) had A(H1N1)pdm09 virus infection, 1857 (47.0%) had A(H3N2), and 805 (20.4%) had influenza B. Of 1398 inpatients, 641 (45.8%) had A(H1N1)pdm09, 532 (38.1%) had A(H3N2), and 225 (16.1%) had influenza B. Outpatients with A(H1N1)pdm09 were younger with fewer comorbidities and were more likely to be hospitalized during the 14-day follow-up (3.3%) than influenza B (2.2%) or A(H3N2) (0.7%; P < .0001). Hospitalized patients with A(H1N1)pdm09 (20.3%) were more likely to be enrolled from intensive care units (ICUs) than those with A(H3N2) (11.3%) or B (9.8%; P < .0001). However, 60-day follow-up of discharged inpatients showed no difference in disease progression (P = .32) or all-cause mortality (P = .30) among influenza types/subtypes. These findings were consistent after covariate adjustment, in sensitivity analyses, and for subgroups defined by age, enrollment location, and comorbidities. Conclusions. Outpatients infected with influenza A(H1N1)pdm09 or influenza B were more likely to be hospitalized than those with A(H3N2). Hospitalized patients infected with A(H1N1)pdm09 were younger and more likely to have severe disease at study entry (measured by ICU enrollment), but did not have worse 60-day outcomes.

AB - Background. Outcome data from prospective follow-up studies comparing infections with different influenza virus types/subtypes are limited. Methods. Demographic, clinical characteristics and follow-up outcomes for adults with laboratory-confirmed influenza A(H1N1)pdm09, A(H3N2), or B virus infections were compared in 2 prospective cohorts enrolled globally from 2009 through 2015. Logistic regression was used to compare outcomes among influenza virus type/subtypes. Results. Of 3952 outpatients, 1290 (32.6%) had A(H1N1)pdm09 virus infection, 1857 (47.0%) had A(H3N2), and 805 (20.4%) had influenza B. Of 1398 inpatients, 641 (45.8%) had A(H1N1)pdm09, 532 (38.1%) had A(H3N2), and 225 (16.1%) had influenza B. Outpatients with A(H1N1)pdm09 were younger with fewer comorbidities and were more likely to be hospitalized during the 14-day follow-up (3.3%) than influenza B (2.2%) or A(H3N2) (0.7%; P < .0001). Hospitalized patients with A(H1N1)pdm09 (20.3%) were more likely to be enrolled from intensive care units (ICUs) than those with A(H3N2) (11.3%) or B (9.8%; P < .0001). However, 60-day follow-up of discharged inpatients showed no difference in disease progression (P = .32) or all-cause mortality (P = .30) among influenza types/subtypes. These findings were consistent after covariate adjustment, in sensitivity analyses, and for subgroups defined by age, enrollment location, and comorbidities. Conclusions. Outpatients infected with influenza A(H1N1)pdm09 or influenza B were more likely to be hospitalized than those with A(H3N2). Hospitalized patients infected with A(H1N1)pdm09 were younger and more likely to have severe disease at study entry (measured by ICU enrollment), but did not have worse 60-day outcomes.

U2 - 10.1093/ofid/ofx212

DO - 10.1093/ofid/ofx212

M3 - Journal article

C2 - 29308401

SN - 2328-8957

VL - 4

JO - Open Forum Infectious Diseases

JF - Open Forum Infectious Diseases

IS - 4

M1 - ofx212

ER -

Comparison of the Outcomes of Individuals With Medically Attended Influenza A and B Virus Infections Enrolled in 2 International Cohort Studies Over a 6-Year Period: 2009-2015

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