Characteristics of patients with hospital-acquired influenza A (H1N1)pdm09 virus admitted to the intensive care unit.
BACKGROUND
Influenza A (H1N1)pdm09 virus infection acquired in the hospital and in critically ill patients admitted to the intensive care unit (ICU) has been poorly characterized.


OBJECTIVE
To assess the clinical impact of hospital-acquired infection with influenza A (H1N1)pdm09 virus in critically ill patients.


METHODS
Analysis of a prospective database of the Spanish registry (2009-2015) of patients with severe influenza A admitted to the ICU. Infection was defined as hospital-acquired when diagnosis and starting of treatment occurred from the seventh day of hospital stay with no suspicion on hospital admission, and community-acquired when diagnosis was established within the first 48 h of admission.


RESULTS
Of 2421 patients with influenza A (H1N1)pdm09 infection, 224 (9.3%) were classified as hospital-acquired and 1103 (45.6%) as community-acquired (remaining cases unclassified). Intra-ICU mortality was higher in the hospital-acquired group (32.9% vs 18.8%, P < 0.001). Independent factors associated with mortality were hospital-acquired influenza A (H1N1)pdm09 infection (odds ratio: 1.63; 95% confidence interval: 1.37-1.99), APACHE II score on ICU admission (1.09; 1.06-1.11), underlying haematological disease (3.19; 1.78-5.73), and need of extrarenal depuration techniques (4.20; 2.61-6.77) and mechanical ventilation (4.34; 2.62-7.21).


CONCLUSIONS
Influenza A (H1N1)pdm09 infection acquired in the hospital is an independent factor for death in critically ill patients admitted to the ICU.
Service of Intensive Care Medicine, Hospital del Mar, Barcelona, Spain; Research Group in Critical Disorders (GREPAC), Institut Hospital del Mar d'Investigacions Mèdiques (IMIM), Barcelona, Spain; Universitat Autònoma de Barcelona, Barcelona, Spain.
F
F
Álvarez-Lerma
Service of Intensive Care Medicine, Hospital del Mar, Barcelona, Spain; Research Group in Critical Disorders (GREPAC), Institut Hospital del Mar d'Investigacions Mèdiques (IMIM), Barcelona, Spain. Electronic address: jmarincorral@gmail.com.
J
J
Marín-Corral
Service of Intensive Care Medicine, Hospital del Mar, Barcelona, Spain.
C
C
Vilà
Service of Intensive Care Medicine, Hospital del Mar, Barcelona, Spain; Research Group in Critical Disorders (GREPAC), Institut Hospital del Mar d'Investigacions Mèdiques (IMIM), Barcelona, Spain; CIBER de Enfermedades Respiratorias (CIBERES), Spain; Universitat Pompeu Fabra, Barcelona, Spain.
J R
JR
Masclans
Service of Intensive Care Medicine, St James's Hospital, Dublin, Ireland.
I M
IM
Loeches
Service of Intensive Care Medicine, Hospital General de Catalunya, Sant Cugat del Vallés, Barcelona, Spain.
S
S
Barbadillo
Service of Intensive Care Medicine, Hospital Universitari Mútua de Terrassa, Terrassa, Barcelona, Spain.
F J
FJ
González de Molina
Service of Intensive Care Medicine, Hospital Universitari Joan XXIII, Tarragona, Spain.
A
A
Rodríguez
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D003428:Cross Infection / Q000453:epidemiology / Q000401:mortality / Q000473:pathology* / Q000821:virology*; D005260:Female; D006761:Hospitals; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000302:isolation & purification*; D007251:Influenza, Human / Q000453:epidemiology / Q000401:mortality / Q000473:pathology* / Q000821:virology*; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D013030:Spain; D016019:Survival Analysis; D055815:Young Adult
Community-acquired infections; Critically ill; H1N1 subtype; Infuenza A virus; Mortality; Nosocomial infection