1139. A Three-Year Analysis of Antiviral Prescribing Trends in the United States
Session: Poster Abstract Session: Influenza and H1N1 Diagnosis, Epidemiology, and Viral Outcome
Saturday, October 22, 2011
Room: Poster Hall B1
Background:   The 2009 novel H1N1 influenza virus (H1N1) became a global pandemic. Although US data is available on vaccinations administered and disease trends, data on antiviral medication use has not been reported.  The purpose of this study was to assess use of antivirals in the outpatient setting in the US over 39 months.

Methods:  Systemic antiviral prescriptions (Rx) dispensed in 1/1/2008-3/25/2011 were extracted from the IMS Health© Xponent® database, containing 70% of all Rx projected to a national total. Data included information on the utilization of flumadine, oseltamivir, rimantadine and zanamivir in outpatients. Population estimates and regional grouping of states were defined by the US Census Bureau.  

Results:  16.1 million (M) antiviral Rx were utilized from 1/1/2008-3/25/2011; 4M in 2008, 8.7M in 2009, 1.3M in 2010, and 1.9M from 1/1/2011-3/25/2011.  A 115% increase was observed in 2009 from Rx utilized in 2008, 84% decrease in 2010 from 2009, and a 36% increase from 1/1/11-3/25/11 when compared to all Rx in 2010.  When adjusted for by population, 0.01 Rx were utilized/capita in 2008, 0.03 in 2009, and 0.004 in 2010. 2009 regional growth in the total number of Rx was highest in the West (293%), followed by the Northeast (272%), South (86%) and Midwest (73%).  From 2008 to 2009 growth of antivirals was seen in almost all 50 states (except SD, NE, KS) and in 2010 every state experienced a decrease.  When adjusted for by population, regional use was highest in the South during the study period (2008=0.02 Rx/capita; 2009=0.04; 2010=0.01) and lowest in the West in 2009 (0.02) and the Midwest in 2008 and 2010 (0.01 and 0.001, respectively).  Annual trends in Rx use were observed with peaks in the total number of antiviral Rx in February 2008, a bimodal increase in May and October 2009, and February 2011. 

Conclusion:  With the circulation of 2009 novel H1N1, there was increased prescribing of antivirals when compared to 2008 or 2010.  Without the circulation of H1N1, antiviral Rx decreased in 2010 at levels lower than 2008.  Geographic trends were also observed which may be a result of the different intensity of influenza transmission in different regions of the US.  The first and second outbreaks of the 2009 novel H1N1 influenza strain in the US parallels 2009 antiviral utilization trends.

Subject Category: N. Hospital-acquired and surgical infections, infection control, and health outcomes including general public health and health services research

Sloan Regen, PharmD Candidate1, Jenny Easterling, PharmD Candidate1, Larry Danziger, PharmD2, Robert Hunkler3 and Katie Suda, PharmD, M.S.1, (1)Clinical Pharmacy, University of Tennessee, Memphis, TN, (2)University of Illinois, Chicago, Chicago, IL, (3)IMS Health, Fountain Hills, AZ


S. Regen, None

J. Easterling, None

L. Danziger, None

R. Hunkler, IMS Health: Employee, Salary

K. Suda, None

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