1131. Asthma in Patients Hospitalized with 2009 Pandemic Influenza A (H1N1) — United States, 2009
Session: Poster Abstract Session: Influenza and H1N1 Diagnosis, Epidemiology, and Viral Outcome
Saturday, October 22, 2011
Room: Poster Hall B1
Background: Persons with asthma are at risk for influenza complications and approximately 20% of patients hospitalized with influenza have asthma. During the 2009 pandemic, asthma was the most common co-morbidity among those hospitalized. We describe characteristics of persons with asthma hospitalized with 2009 pandemic influenza A (H1N1) [pH1N1].

Methods: Patient data were derived from two nationally representative U.S. case series of pH1N1 hospitalized patients during spring and fall 2009. A case was defined as a person ≥ 2 years hospitalized with laboratory-confirmed pH1N1.  Asthma status was determined through chart review.  We conducted bivariate analysis to investigate characteristics of patients with asthma compared to those without.

Results: Among 473 pH1N1 hospitalized patients, 29% had asthma. Patients with asthma compared to those without asthma were more likely to be <18 years old (39% vs. 30%, p=0.04) and black (29% vs. 18%, p<0.01); median time between illness onset and admission (2 days vs. 3 days) and length of stay (3 days vs. 3 days) were similar.  Chronic renal disease (2% vs 11%, p<0.01) was less common among patients with asthma but there were no significant differences in prevalence of other co-morbidities.  Patients with asthma compared to those without were less likely to have pneumonia (37% vs. 47%, p=0.05) or a positive sterile site culture (0.7% vs. 3.9%, p=0.11), need mechanical ventilation (13% vs. 23%, p=0.02), and die (4% vs. 10%, p=0.04).  Receipt of influenza antiviral agents was similar in both groups, but receipt of oral or intravenous steroids was significantly higher in those with asthma.  Among persons with asthma, those admitted to an intensive care unit (ICU) or who died (n=38) compared with survivors not admitted to an ICU (n=99) were more likely to be tachypneic (61% vs. 37%, p=0.01), and have pneumonia (60% vs. 27%, p<0.01) or acute respiratory distress syndrome (24% vs. 0%, p<0.01).

Conclusion: Asthma was common among pH1N1 hospitalized patients; the majority had an uncomplicated course and may have been admitted for an acute asthma exacerbation. However, pH1N1 patients with asthma and pneumonia or respiratory distress did poorly.  Prevention with influenza vaccination in persons with asthma should be prioritized.

Subject Category: V. Virology including clinical and basic studies of viral infections, including hepatitis

John McKenna, BS1, Anna M. Bramley, MPH2, Jacek Skarbinski, MD3, Alicia Fry, MD, MPH4, Lyn Finelli, DrPH, MS4 and Seema Jain, MD4, (1)CDC Foundation, Atlanta, GA, (2)Influenza Division, Centers for Disease Control and Prevention, Atlanta, GA, (3)Division of Parasitic Diseases, Centers for Disease Control and Prevention, Atlanta, GA, (4)Centers for Disease Control and Prevention, Atlanta, GA


J. McKenna, External Medical Affairs, Pfizer Inc.: grant recipient through the CDC Foundation, Grant recipient

A. M. Bramley, None

J. Skarbinski, None

A. Fry, None

L. Finelli, None

S. Jain, None

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