Factors associated with poor outcomes among adults hospitalized for influenza in France: A three-year prospective multicenter study.
Influenza is an important cause of serious illness and death, particularly in elderly and high-risk groups.



Aim of this study was to identify factors associated with poor outcomes among adults hospitalized in France for laboratory-confirmed seasonal influenza.



Patients hospitalized for influenza were identified in a prospective, multicenter study carried out in French hospitals during three consecutive influenza seasons (2012-2015). Influenza virus infection was confirmed by reverse transcription polymerase chain reaction. Sociodemographic and clinical variables were compared according to the virus type and subtype. Risk factors for complications, intensive care unit (ICU) admission and death were analyzed by backward stepwise logistic regression.



The study population consisted of 566 patients, of whom 56% were older than 65 years and 82% had underlying chronic illnesses. Type A influenza viruses infected 422 patients (75%), including subtype H3N2 in 239 patients (57%). The prior vaccine coverage rate was 38%. Complications occurred in 255 patients (45%), consisting mainly of pneumonia (n=143, 30%) and respiratory failure (n=116, 20%). Eighty-three patients (15%) were admitted to an ICU, and the in-hospital mortality rate was 4% (n=21). Sixty-six patients (12%) received oseltamivir. Age over 65 years was the only identified risk factor for complications. Risk factors for ICU admission were an absence of vaccination, no oseltamivir administration before admission, pre-existing chronic respiratory disease, and current smoking. Age over 65 years and ICU admission were risk factors for death.



Older individuals and patients with underlying conditions are most at risk of influenza complications. Vaccination and early oseltamivir administration, both of which are recommended for these patients, appear to reduce ICU admissions.
Inserm, CIC 1417, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France; Department of Infectious Diseases, CIC Cochin Pasteur, Cochin Broca Hôtel-Dieu hospital, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France.
Paul
P
Loubet
Inserm, F-CRIN, Innovative Clinical Research Network in Vaccinology (I-REIVAC), Paris, France.
Nezha
N
Samih-Lenzi
CHRU de Montpellier, CIC 1411, Hôpital Saint-Eloi, Montpellier, France.
Florence
F
Galtier
Service d'Hygiène, Epidémiologie et Prévention, Groupement Hospitalier Edouard Herriot, Lyon, France; Emerging Pathogens Laboratory - Fondation Mérieux, Centre International de Recherche en Infectiologie (CIRI) Inserm U1111, CNRS UMR5308, ENS de Lyon, UCBL1, 21, Avenue Tony Garnier, Lyon 69007, France.
Philippe
P
Vanhems
Inserm, CIC 1417, Paris, France; Department of Infectious Diseases, CIC Cochin Pasteur, Cochin Broca Hôtel-Dieu hospital, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France; Inserm, F-CRIN, Innovative Clinical Research Network in Vaccinology (I-REIVAC), Paris, France.
Pierre
P
Loulergue
Inserm CIC 1425, Hôpital Bichat-Claude Bernard, APHP, Paris, France; IAME UMR 1137, Univ Paris Diderot, Sorbonne Paris Cité, F-75019 Paris, France.
Xavier
X
Duval
Centre Hospitalo-Universitaire de Rennes, Service de Pneumologie, IRSET UMR 1085, Université de Rennes 1, Rennes, France.
Stéphane
S
Jouneau
CHU Dupuytren, CIC 1435, Limoge Cedex, France.
Déborah
D
Postil
CHU Dupuytren, Service Bactériologie, Virologie, Hygiène, Limoges Cedex, France.
Sylvie
S
Rogez
CNR Virus Influenza, Hospices Civils de Lyon, Bron, University of Lyon, Lyon, France.
Martine
M
Valette
CHRU de Montpellier, Service de Maladies Infectieuses et Tropicales, Hôpital Saint-Eloi, Montpellier, France.
Corinne
C
Merle
Université Lyon 1, Laboratoire de Biométrie et Biologie Evolutive, UMR CNRS 5558, France, France.
Corinne
C
Régis
Inserm CIC 1425, Hôpital Bichat-Claude Bernard, APHP, Paris, France.
Yolande
Y
Costa
Inserm, F-CRIN, Innovative Clinical Research Network in Vaccinology (I-REIVAC), Paris, France.
Zineb
Z
Lesieur
CHRU de Rennes, Service de Maladies Infectieuses et Tropicales, Rennes, France.
Pierre
P
Tattevin
CNR Virus Influenza, Hospices Civils de Lyon, Bron, University of Lyon, Lyon, France.
Bruno
B
Lina
Sorbonne Universités, UPMC Univ Paris 06, INSERM, Institut Pierre Louis d'Epidémiologie et de Santé Publique (IPLESP UMRS 1136), F75012, Paris, France; Public health department, Hopital Saint-Antoine, APHP, Paris, France.
Fabrice
F
Carrat
Inserm, CIC 1417, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France; Department of Infectious Diseases, CIC Cochin Pasteur, Cochin Broca Hôtel-Dieu hospital, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France; Inserm, F-CRIN, Innovative Clinical Research Network in Vaccinology (I-REIVAC), Paris, France. Electronic address: odile.launay@cch.aphp.fr.
Odile
O
Launay
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015897:Comorbidity; D016021:Epidemiologic Studies; D005260:Female; D005602:France / Q000453:epidemiology; D006760:Hospitalization; D006801:Humans; D007251:Influenza, Human / Q000453:epidemiology / Q000401:mortality* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D016019:Survival Analysis; D016896:Treatment Outcome; D055815:Young Adult
Adults; Antiviral; Hospitalisation; Influenza; Severe; Vaccination