Co-authored by John Billings of NYU's Robert F. Wagner Graduate School of Public Service and Maria C. Raven of the University of California and published in the December issue of Health Affairs, the new analysis of hospital emergency department (ED) use in New York City by Medicaid patients reveals that conditions related to substance abuse and mental illness are responsible for a small share of the emergency department visits by frequent ED users, and that ED use accounts for a small portion of these patients' total Medicaid expenditures. However, according to the study, frequent emergency department users have a substantial burden of disease, often having multiple chronic conditions and many hospitalizations.

The article, "Dispelling an Urban Legend: Frequent Emergency Department Users Have Substantial Burden of Disease," analyzes data on emergency department visits by 212,259 New York City residents who received their first emergency department care in 2007. The researchers reviewed each patient's eligibility, ED use, Medicaid fee-for-service spending, and diagnostic history. The main part of the analysis covers the three years before each patient's first visit to a hospital emergency department, the 12 months after the initial visit, and the subsequent two years. As the authors write, "contrary to urban legend, most repeat users in the study did appear to have relatively strong linkage to ambulatory care, at least as evidenced by their high rates of primary and specialty care visits. Except for ED users with ten or more visits in the index [initial] year, ambulatory care visit rates actually exceeded ED visit rates."

While hospital emergency department use is not a major cost driver for the Medicaid program, an improved understanding of Medicaid beneficiaries who frequently obtain ED care could help inform the current policy debate over how to meet the significant needs of this population and how to contain Medicaid expenditures, according to the researchers.

Importantly, the analysis indicates that "predictive modeling" based on information provided at a patient's initial ED visit could be used to identify individuals likely to return to the emergency department frequently. Billings and Raven write that the predictive modeling approach, coupled with an understanding of the characteristics of frequent ED users, offers health care institutions an opportunity to design targeted, cross-system health care interventions to keep future high users from having to return to the hospital for emergency care.

"It is also important to note that only a small number of 'frequent fliers' are ultra-high ED users or serial high ED users, with frequent ED use year after year," Billings and Raven assert. "To date, most thinking by providers and policy makers about the problem of frequent ED users has focused on these serial users, but the overwhelming majority of frequent users have only episodic periods of high ED use, instead of consistent use over multiple years. More needs to be learned about these patients (they, too, could be interviewed in the ED), and predictive modeling and quick intervention will probably be critical since their repeat ED use is unlikely to continue over time."