Seasonal influenza accounts for a high proportion of outpatient morbidity during the winter months. However, influenza case counts are greatly underestimated due to frequently undiagnosed influenza. Electronic medical record (EMR) systems provide a very large, complex data source for influenza surveillance at both the patient and population level. It is important to identify influenza patients for specimen collection, respiratory isolation for school age children, prescription of an appropriate influenza drug, or to identify patients at risk for complications. At a population level, public health agencies monitor the tempo and spread of influenza season for resource management, as well as maintain situational awareness for avian influenza.
Objective
The objective of this work was to evaluate the utility of classification tree methods for syndromic surveillance case definition development using an EMR system as a data source.