Predictors of influenza in the adult population during seasonal and A(H1N1)pdm09 pandemic influenza periods.
We aimed to assess whether the characteristics of influenza-like illness (ILI) cases in the general population were similar during the seasonal and pandemic A(H1N1)pdm09 influenza periods. We conducted a study using a general population database, which included demographic (sex, age) and clinical (underlying medical conditions, influenza vaccination status) information on more than 80 000 subjects. We assessed the most important predictors of ILI during each season by using multiple logistic regression. We descriptively compared whether they were similar during different seasons. The model, including all demographic and clinical characteristics, showed that age ⩾60 years decreased the odds for ILI by 52% and 81% during the seasonal and A(H1N1)pdm09 pandemic periods, respectively. Being vaccinated decreased the odds of ILI for seasonal influenza by 32%, while suffering from the comorbidities other than lung or cardiovascular diseases doubled the odds of ILI during the A(H1N1)pdm09 pandemic.
University of Groningen, Department of Pharmacy, PharmacoEpidemiology & PharmacoEconomics (PE2), Groningen, The Netherlands.
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G
Gefenaite
Radboud University Nijmegen Medical Centre, Scientific Institute for Quality of Healthcare (IQ Healthcare), Nijmegen, The Netherlands.
M
M
Tacken
University of Groningen, Department of Pharmacy, PharmacoEpidemiology & PharmacoEconomics (PE2), Groningen, The Netherlands.
J
J
Kolthof
University of Groningen, Department of Pharmacy, PharmacoEpidemiology & PharmacoEconomics (PE2), Groningen, The Netherlands.
B
B
Mulder
NIVEL, Netherlands Institute for Health Services Research, Utrecht, The Netherlands.
J C
JC
Korevaar
NIVEL, Netherlands Institute for Health Services Research, Utrecht, The Netherlands.
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I
Stirbu-Wagner
University of Groningen, Department of Pharmacy, PharmacoEpidemiology & PharmacoEconomics (PE2), Groningen, The Netherlands.
J
J
Bos
University of Groningen, University Medical Center Groningen, Department of Epidemiology, Groningen, The Netherlands.
R P
RP
Stolk
University of Groningen, Department of Pharmacy, PharmacoEpidemiology & PharmacoEconomics (PE2), Groningen, The Netherlands.
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E
Hak
D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000453:epidemiology* / Q000821:virology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D055815:Young Adult