Pandemic influenza (H1N1) 2009 pneumonia: CURB-65 score for predicting severity and nasopharyngeal sampling for diagnosis are unreliable.
BACKGROUND
From the first case reports of pandemic influenza (H1N1) 2009 it was clear that a significant proportion of infected individuals suffered a primary viral pneumonia. The objective of this study was twofold; to assess the utility of the CURB-65 community acquired pneumonia (CAP) severity index in predicting pneumonia severity and ICU admission, and to assess the relative sensitivity of nasopharyngeal versus lower respiratory tract sampling for the detection of pandemic influenza (H1N1) CAP.


METHODS
A retrospective cohort study of 70 patients hospitalised for pandemic influenza (H1N1) 2009 in an adult tertiary referral hospital. Characteristics evaluated included age, pregnancy status, sex, respiratory signs and symptoms, smoking and alcohol history, CURB-65 score, co-morbidities, disabling sequelae, length of stay and in-hospital mortality outcomes. Laboratory features evaluated included lymphocyte count, C-reactive protein (CRP), nasopharyngeal and lower respiratory tract pandemic influenza (H1N1) 2009 PCR results.


RESULTS
Patients with pandemic (H1N1) 2009 influenza CAP differed significantly from those without pneumonia regarding length of stay, need for ICU admission, CRP and the likelihood of disabling sequelae. The CURB-65 score did not predict CAP severity or the need for ICU admission (only 2/11 patients admitted to ICU had CURB-65 scores of 2 or 3). Nasopharyngeal specimens for PCR were only 62.9% sensitive in CAP patients compared to 97.8% sensitivity for lower respiratory tract specimens.


CONCLUSIONS
The CURB-65 score does not predict severe pandemic influenza (H1N1) 2009 CAP or need for ICU admission. Lower respiratory tract specimens should be collected when pandemic (H1N1) 2009 influenza CAP is suspected.
Mulrennan
Siobhain
S
Department of Respiratory Medicine, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia. Siobhain.Mulrennan@health.wa.gov.au
Tempone
Simone Sara
SS
Ling
Ivan Thian Wai
IT
Williams
Simon Hedley
SH
Gan
Gek-Choo
GC
Murray
Ronan John
RJ
Speers
David John
DJ
D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006760:Hospitalization; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D007251:Influenza, Human / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology / Q000821:virology; D008297:Male; D008875:Middle Aged; D009305:Nasopharynx / Q000821:virology*; D058873:Pandemics; D011014:Pneumonia / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology / Q000821:virology; D012137:Respiratory System / Q000821:virology; D012189:Retrospective Studies; D012720:Severity of Illness Index; D055815:Young Adult