Differences between asthmatics and nonasthmatics hospitalised with influenza A infection.
Asthmatics hospitalised because of influenza A infection are less likely to require intensive care or die compared with nonasthmatics. The reasons for this are unknown. We performed a retrospective analysis of data on 1520 patients admitted to 75 UK hospitals with confirmed influenza A/H1N1 2009 infection. A multivariable model was used to investigate reasons for the association between asthma and severe outcomes (intensive care unit support or death). Asthmatics were less likely than nonasthmatics to have severe outcome (11.2% versus 19.8%, unadjusted OR 0.51, 95% CI 0.36-0.72) despite a greater proportion requiring oxygen on admission (36.4% versus 26%, unadjusted OR 1.63) and similar rates of pneumonia (17.1% versus 16.6%, unadjusted OR 1.04). The results of multivariable logistic regression suggest the association of asthma with outcome (adjusted OR 0.62, 95% CI 0.36-1.05; p=0.075) are explained by pre-admission inhaled corticosteroid use (adjusted OR 0.34, 95% CI 0.18-0.66) and earlier admission (≤ 4 days from symptom onset) (adjusted OR 0.60, 95% CI 0.38-0.94). In asthmatics, systemic corticosteroids were associated with a decreased likelihood of severe outcomes (adjusted OR 0.36, 95% CI 0.18-0.72). Corticosteroid use and earlier hospital admission explained the association of asthma with less severe outcomes in hospitalised patients.
University of Nottingham, Nottingham.
Puja
P
Myles
Jonathan S
JS
Nguyen-Van-Tam
Malcolm G
MG
Semple
Stephen J
SJ
Brett
Barbara
B
Bannister
Robert C
RC
Read
Bruce L
BL
Taylor
Jim
J
McMenamin
Joanne E
JE
Enstone
Karl G
KG
Nicholson
Peter J
PJ
Openshaw
Wei Shen
WS
Lim
D000293:Adolescent; D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001249:Asthma / Q000150:complications*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D015897:Comorbidity; D005260:Female; D006760:Hospitalization; D006801:Humans; D007223:Infant; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000150:complications* / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D011379:Prognosis; D062486:Public Health Surveillance; D015272:Pulmonary Medicine / Q000379:methods; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome; D006113:United Kingdom; D055815:Young Adult
D000305:Adrenal Cortex Hormones