Influenza Antiviral Prescribing for Outpatients with an Acute Respiratory Illness and at High Risk for Influenza-Associated Complications during Five Influenza Seasons—United States, 2011–2016

Abstract

Background

Influenza causes millions of illnesses annually; certain groups are at higher risk for influenza-associated complications. Early antiviral treatment can reduce the risk of complications and is recommended for outpatients at increased risk. We describe antiviral prescribing among high-risk outpatients for 5 influenza seasons and explore factors that may influence prescribing.

Methods

We analyzed antiviral prescription and clinical data for high-risk outpatients aged ≥ 6 months with an acute respiratory illness (ARI) and enrolled in the US Influenza Vaccine Effectiveness Network during the 2011–2012 to 2015–2016 influenza seasons. We obtained clinical information from interviews and electronic medical records and tested all enrollees for influenza with rRT-PCR. We calculated the number of patients with ARI that must be treated to treat 1 patient with laboratory-confirmed influenza.

Results

Among high-risk outpatients with ARI who presented to care within two days of symptom onset (early), 15% (718/4861) were prescribed an antiviral medication, including 472/1292 (37%) of those with rRT-PCR-confirmed influenza. Less than half (40%) of high-risk outpatients with influenza presented to care early. Earlier presentation to care was associated with antiviral treatment (OR: 4.1, CI: 3.5–4.8), as was fever (OR: 3.2, CI: 2.7–3.8), although 25% of high-risk outpatients with influenza were afebrile. Empiric treatment of 4 high-risk outpatients with ARI was needed to treat 1 patient with laboratory-confirmed influenza.

Conclusion

Influenza antiviral medications were infrequently prescribed for high-risk outpatients with ARI who would benefit most from treatment. Efforts to increase appropriate antiviral prescribing are needed to reduce influenza-associated complications.