Does Antimicrobial Prescription Data Improve Influenza Surveillance in VA?

Whether antiviral or antibacterial prescriptions correlate with influenza coded encounters is unknown. Oseltamivir, zanamivir and azithromycin outpatient prescriptions from VA Corporate Data Warehouse and respiratory syndrome, influenza-like-illness (ILI) and influenza-specific ICD-9-CM coded visits from outpatient ESSENCE were analyzed for the 2010-2012 influenza seasons in all VA medical centers and outpatient clinics. Significantly more ILI and respiratory syndrome encounters occurred compared to antiviral prescriptions dispensed with marginal temporal correlation between visits and antiviral prescriptions. Azithromycin prescriptions tracked closely with the onset and peaks of the influenza season. Surprisingly, antiviral prescription data provided minimal additional information for influenza trend monitoring in VA