489. Influenza Testing and Antiviral Prescriptions During Acute Respiratory Illness Hospitalizations — October 2010–April 2013
Session: Poster Abstract Session: Respiratory Infections: Influenza
Thursday, October 8, 2015
Room: Poster Hall
Background: Due to low influenza test sensitivity or delays in results, prompt, empiric influenza antiviral treatment is recommended for hospitalized patients with suspected influenza. However, the frequency of empiric treatment is not well understood. We describe influenza testing and antiviral prescriptions in persons hospitalized with acute respiratory illness (ARI) during three influenza seasons (October 1–April 30) at a large, tertiary care hospital in the US. 

Methods: Administrative records from the 2010–13 influenza seasons were reviewed for ARI hospitalizations using pre-selected diagnostic codes. PCR- and antigen-based panel assays were available. Testing (within 3 days of admission) and antiviral prescriptions were compared by patient age, high-risk conditions, and intensive care unit (ICU) admission. Antivirals prescribed without the aid of diagnostic tests were considered empiric. Season- and age-adjusted rates were estimated from Poisson regression. 

Results: Among 27,137 ARI hospitalizations, 33% were tested for influenza, 9% were positive, and 2% were prescribed influenza antivirals. Overall, 25% of tests were PCR-based. Treatment was strongly associated with testing (rate ratio=15.0, p-value<0.01). While testing was greater among young children (64%) than adults ≥65 years (32%), antiviral treatment was greater among older adults (2% v. 0.8% in those <2 years). Testing, though not treatment, was significantly higher among inpatients with high-risk conditions (p-value<0.01). Empiric therapy was rare, occurring for 0.6% of ARI hospitalizations and 0.9% of tested admissions, and not associated with age, high-risk condition, or ICU admission. Among patients with laboratory-confirmed influenza, 65% were treated. 

Conclusion: In our study, although not all hospitalizations were influenza-associated, testing for influenza was uncommon and empiric antiviral treatment was rare among inpatients with ARI during influenza seasons. While laboratory-confirmed influenza cases were often treated, reliance on antigen-based assays can miss true influenza cases due to false negative results. Exploration of the cost and benefits of test-and-treat strategies that include use of newer molecular assays, is warranted.

Melissa a. Rolfes, PhD, MPH1, Kimberly Yousey-Hindes, MPH, CPH2, James I. Meek, MPH2, Alicia M. Fry, MD, MPH1 and Sandra S. Chaves, MD, MSc1, (1)Influenza Division, Centers for Disease Control and Prevention, Atlanta, GA, (2)Connecticut Emerging Infections Program, Yale School of Public Health, New Haven, CT

Disclosures:

M. A. Rolfes, None

K. Yousey-Hindes, None

J. I. Meek, None

A. M. Fry, None

S. S. Chaves, None

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