We hypothesized that using communitywide data from a health information exchange (HIE) could improve the ability to identify frequent emergency department (ED) users-those with four or more ED visits in thirty days-by allowing ED use to be measured across unaffiliated hospitals. When we analyzed HIE-wide data instead of site-specific data, we identified 20.3 percent more frequent ED users (5,756 versus 4,785) and 16.0 percent more visits by them to the ED (53,031 versus 45,771). Additionally, we found that 28.8 percent of frequent ED users visited multiple EDs during the twelve-month study period, versus 3.0 percent of all ED users. All three differences were significant ($$p ). An improved ability to identify frequent ED users allows better targeting of case management and other services that can improve frequent ED users' health and reduce their use of costly emergency medical services.
Keywords: Information Technology; Quality Of Care; Safety-Net Systems.