Trends in interfacility transfer volume by season, day of week, time of day, and federal holiday status

Background

Interfacility transfer patients have poorer outcomes and greater resource needs than the average emergency department (ED) patient, however, trends in transfer rates remain poorly understood.

Objective

To quantify temporal trends in the volume of interfacility transfers to the emergency department of an academic referral center.

Methods

A retrospective review was performed of all adult patients transferred to the ED of a large, academic medical center in the Northeastern U.S. from 2017 to 2019. The mean transfer and total ED volumes by season, day of week, time of day, and federal holiday status were calculated and compared.

Results

A total of 26,555 adult patients were transferred to the hospital ED from 2017 to 2019. Transfer volume increased by 13% over the study period while total ED volume increased by less than 1%. While transfer patients made up, on average, only 8.6% of ED patients during day shifts, this proportion increased to 16.5% during evening shifts and 18.8% during night shifts. A modest, cyclical weekday pattern was also noted, with the proportion of ED volume from transfers reaching its highest on Saturdays and its lowest on Wednesdays. No consistent trends in transfer volume due to season or holiday status were observed.

Conclusion

Our center's significant two-year increase in interfacility transfer volume and relative stagnation in total ED volume illustrates an expanding role supporting community facilities. Consequently, transfer patients accounted for an increasing proportion of ED providers' workload during evening shifts and during overnight shifts. Referral centers may benefit from performing similar analyses of their own transfer volume to inform ED resource allocation.