Biosurveillance of ED visits for gastroenteritis.

Abstract Objective Our objective was to characterize emergency department (ED) visits for gastroenteritis by season and age and develop a predictive model. Methods We performed a retrospective cohort study of patients seen in 19 EDs from 1988 to 2002. We examined differences in the annual peaks of younger ( 60 months) age groups and developed a time series regression model. Results Of the 5182019 total visits, 88504 were for gastroenteritis. On average, the percentage of gastroenteritis on the peak days was higher in the younger (26%) than older group (4%), and the peaks for the younger group occurred 36 days after those for the older group. Conclusion Emergency department visits for gastroenteritis vary greatly by season and age. Our time series predictive model was a good fit to actual incidence patterns. These variations should be accounted for in designing a system to detect bioterrorism and for surveillance of naturally occurring epidemics.