Population Dynamics in the Elderly: The Need for Age-Adjustment in National BioSurveillance Systems

With the growing threat of pandemic influenza, efforts to improve national surveillance to better predict and prevent this disease from affecting the most vulnerable populations are being undertaken. This paper examines the utility of Medicare data to obtain age-specific influenza hospitalization rates for historical analyses. We present a novel approach to describing and analyzing age-specific patterns of hospitalizations using Medicare data and show the implications of a dynamic population age distribution on hospitalization rates. We use these techniques to highlight the utility of implementing a real-time nationwide surveillance system for influenza cases and vaccination, and discuss opportunities to improve the existing system to inform policy and reduce the burden of influenza nationwide.