Forecasting emergency department (ED) visits is a well-studied topic. The importance of understanding the complexity of patients along with the days and times of varying patient volumes is critical for planning medical and ancillary staffing. Though multiple studies stratify their results based on severity of disease, severity was determined by triage status. The goal of this study was to utilize a novel method to evaluate the correlation between daily emergency department patient complexity, based on Current Procedure Terminology (CPT) code, and day of the week.

This was a retrospective study of subjects presenting to the ED between January 1, 2010 and December 31, 2015. We identified the correlation between subjects with each CPT code who were evaluated on a specific day of the week and evaluated the day before, the day of and the day after a legal holiday.

During the study period 312,550 (48%) male and 336,348 (52%) female subjects were identified. No correlation between daily ED patient complexity, based on CPT code, and day of the week (p=0.75) or any legal holidays were identified. Individual significant differences were noted among day of the week and particular CPT code as well as legal holiday and particular CPT code with no appreciable trend or pattern.

There was no correlation between daily ED patient complexity based on CPT code and day of the week or daily ED patient acuity and legal holiday. In light of these data, emergency department staffing and resource allocation patterns may need to be revisited.