The Transfer Instability Index: A Novel Metric of Emergency Department Transfer Relationships

Abstract

Objectives: In this study, the objective was to characterize emergency department (ED) transfer relationships and study the factors that predict the stability of those relationships. A metric is derived for ED transfer relationships that may be useful in assessing emergency care regionalization and as a resource for future emergency medicine research.Methods: Emergency department records at transferring hospitals were linked to ED and inpatient records at receiving hospitals in nine U.S. states using the 2010 Healthcare Cost and Utilization Project State Emergency Department Databases and State Inpatient Databases, the American Hospital Association Annual Survey, and the Trauma Information Exchange Program. Using the Clinical Classification Software to categorize conditions, high transfer rate conditions were placed into nine clinical groups. The authors created a new measure, the "transfer instability index," which estimates the effective number of "transfer partners" for each sending ED: this is designed to measure the stability of outgoing transfer relationships, where higher values of the index indicate less stable relationships. The index provides a measure of how many hospitals a transferring hospital sends its patients to (weighted by how often each transfer partner is used). Regression was used to analyze factors associated with higher values of the index.Results: Sending hospitals had a median of 3.5 effective transfer partners across all conditions. The calculated transfer instability indices varied from 1 to 2.4 across disease categories. In general, higher index values were associated with treating a higher proportion of publicly insured patients: 10 and 12% increases in the Medicare and Medicaid share of ED encounters, respectively, were associated with 10 and 14% increases in the effective number of transfer partners. This public insurance effect held while studying all conditions together as well as within individual disease categories, such as cardiac, neurologic, and traumatic conditions.Conclusions: United States EDs that transfer patients to other hospitals often have multiple transfer partners. The stability of the transfer relationship, assessed by the transfer instability index, differs by condition. Less stable transfer relationships (i.e., hospitals with greater numbers of transfer partners) were more common in EDs with higher proportions of publicly insured patients.ACADEMIC EMERGENCY MEDICINE 2015;22:166-171

Social network analysis of nationwide interhospital emergency department transfers in Taiwan

“…In the United States, the national ED transfer rate was about 1–2% 27 – 29 , a figure that was comparable to ours (1%). A variety of factors have been reported to be associated with the decision to transfer: patient factors, insurance types, hospital factors, geography, resource level, and healthcare market 1 , 30 , 31 . In a previous study, the primary reason for transfers was for a higher level of care 29 , which was different from our primary reason of “requests from patients or families.” However, this may be a classification issue because the original question did not have a response choice of higher-level care.…”

“…Coupled with a government-run, single-payer health care system, the administrative complexity is substantially reduced. Another metric suggestive of a more regionalized network is a lower number of transfer-out partners 28 , 31 . In our study, that number was a median of 5 partners over three years, compared to a median of 7 over a year from a previous US study 28 .…”

Comparing definitions of a pediatric emergency department

“…Because the AHA often groups EDs by hospital network, it can make it difficult to calculate volume-based ED metrics for specific sites. Because SEDDs/SIDs are frequently used for the evaluation of emergency services and health services research, 9,11,[15][16][17][18] understanding the limitations of those databases for identifying primary pediatric hospitals within larger health systems is critically important for researchers. In particular, understanding how the use of standardized linkage methodology can "hide" pediatric volume within medical systems is important, especially for investigators planning to examine pediatric care within general EDs or to compare pediatric care between general EDs and pediatric EDs.…”

Harnessing the Power of Administrative Data for Measuring the Regionalization of Emergency Care

“…In this issue of Academic of Emergency Medicine , two articles by Kindermann et al . provide the first comprehensive understanding of ED transfer patterns in the United States by taking advantage of this powerful AHRQ data from nine states.…”

“…In a second companion analysis published in this issue, Kindermann et al . examine the variation in the number of transfer partners an ED has as a potential metric of the coordination of regionalized emergency care systems, what they define as the transfer instability index .…”