Influenza burden for children with asthma.
OBJECTIVE
The goal was to estimate the influenza disease burden among children with asthma and among healthy children by using active, laboratory-confirmed, population-based surveillance.


METHODS
Children 6 to 59 months of age residing in 3 US counties who were hospitalized with acute respiratory illnesses or fever were enrolled prospectively from 2000 through 2004. Similar children who presented to clinics and emergency departments during 2 of the influenza seasons (2002-2004) were enrolled. Rates of influenza-attributable outpatient visits and hospitalizations for children with asthma and for healthy children were estimated. History of asthma and receipt of influenza vaccine for the study children were determined through parental report. The prevalence of asthma in the surveillance population was assumed to be 6.2% for children 6 to 23 months of age and 12.3% for children 24 to 59 months of age.


RESULTS
Of 81 children 6 to 59 months of age with influenza-confirmed hospitalizations in 2000 to 2004, 19 (23%) had asthma. Average annual influenza-attributable hospitalization rates were significantly higher among children with asthma than among healthy children 6 to 23 months of age (2.8 vs 0.6 cases per 1000 children) but not children 24 to 59 months of age (0.6 vs 0.2 case per 1000 children). Of 249 children 6 to 59 months of age with influenza-confirmed outpatient visits in 2002 to 2004, 38 (15%) had asthma. Estimated outpatient influenza-attributable visit rates were higher among children with asthma than among healthy children 6 to 23 months of age (316 vs 152 cases per 1000 children) and 24 to 59 months of age (188 vs 102 cases per 1000 children) in 2003 to 2004. Few parents reported that their children had been vaccinated, including <30% of children with asthma.


CONCLUSIONS
Influenza-attributable health care utilization is high among children with asthma and is generally higher than among healthy children.
Miller
E Kathryn
EK
Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
Griffin
Marie R
MR
Edwards
Kathryn M
KM
Weinberg
Geoffrey A
GA
Szilagyi
Peter G
PG
Staat
Mary A
MA
Iwane
Marika K
MK
Zhu
Yuwei
Y
Hall
Caroline B
CB
Fairbrother
Gerry
G
Seither
Ranee
R
Erdman
Dean
D
Lu
Pengjun
P
Poehling
Katherine A
KA
D017677:Age Distribution; D001249:Asthma / Q000175:diagnosis / Q000453:epidemiology*; D016022:Case-Control Studies; D002675:Child, Preschool; D015897:Comorbidity; D005260:Female; D005500:Follow-Up Studies; D006306:Health Surveys; D017721:Hospital Costs; D006760:Hospitalization / Q000191:economics* / Q000706:statistics & numerical data; D006801:Humans; D015994:Incidence; D007223:Infant; D007251:Influenza, Human / Q000175:diagnosis / Q000191:economics* / Q000453:epidemiology*; D008297:Male; D011336:Probability; D012016:Reference Values; D012141:Respiratory Tract Infections / Q000175:diagnosis / Q000453:epidemiology; D018570:Risk Assessment; D012720:Severity of Illness Index; D017678:Sex Distribution; D018709:Statistics, Nonparametric; D014481:United States / Q000453:epidemiology