Frequent users of emergency department services: gaps in knowledge and a proposed research agenda.

Frequent use of emergency department (ED) services is often perceived to be a potentially preventable misuse of resources. The underlying assumption is that similar and more appropriate care can be delivered outside of EDs at a lower cost. To reduce costs and incentivize more appropriate use of services, there have been efforts to design interventions to transition health care utilization of frequent users from EDs to other settings such as outpatient clinics. Many of these efforts have succeeded in smaller trials, but wider use remains elusive for varying reasons. There are also some fundamental problems with the assumption that all or even the majority of frequent ED use is misuse and invoking reasons for that excessive use. These tenuous assumptions become evident when frequent users as a group are compared to less frequent users. Specifically, frequent users tend to have high levels of frequent ED use, have a higher severity of illness, be older, have fewer personal resources, be chronically ill, present for pain-related complaints, and have government insurance (Medicare or Medicaid). Because of the unique characteristics of the population of frequent users, we propose a research agenda that aims to increase the understanding of frequent ED use, by: 1) creating an accepted categorization system for frequent users, 2) predicting which patients are at risk for becoming or remaining frequent users, 3) implementing both ED- and non-ED-based interventions, and 4) conducting qualitative studies of frequent ED users to explore reasons and identify factors that are subject to intervention and explore specific differences among populations by condition, such as mental illness and heart failure.