  Emergency department (ED) care for frail elderly patients is associated with
an increased use of resources due to their complex medical needs and frequently
difficult psycho-social situation. To better target their needs with specially
trained staff, it is vital to determine the times during which these particular
patients present to the ED. Recent research was inconclusive regarding this
question and the applied methods were limited to coarse time windows. Moreover,
there is little research on time variation of frail ED patients' case
complexity. This study examines differences in arrival rates for frail vs.
non-frail patients in detail and compares case complexity in frail patients
within vs. outside of regular GP working hours. Arrival times and case
variables (admission rate, ED length of stay [LOS], triage level and
comorbidities) were extracted from the EHR of an ED in an urban German teaching
hospital. We employed Poisson time series regression to determine patterns in
hourly arrival rates over the week. Frail elderly patients presented more
likely to the ED during already high frequented hours, especially at midday and
in the afternoon. Case complexity for frail patients was significantly higher
compared to non-frail patients, but varied marginally in time only with respect
to triage level and ED LOS. The results suggest that frailty-attuned emergency
care should be available in EDs during the busiest hours. Based on EHR data,
hospitals thus can tailor their staff needs.
