  Frequent users of emergency departments (ED) pose a significant challenge to
hospital emergency services. Despite a wealth of studies in this field, it is
hardly understood, what medical conditions lead to frequent attendance. We
examine (1) what ambulatory care sensitive conditions (ACSC) are linked to
frequent use, (2) how frequent users can be clustered into subgroups with
respect to their diagnoses, acuity and admittance, and (3) whether frequent use
is related to higher acuity or admission rate. We identified several ACSC that
highly increase the risk for heavy ED use, extracted four major diagnose
subgroups and found no significant effect neither for acuity nor admission
rate. Our study indicates that especially patients in need of (nursing) care
form subgroups of frequent users, which implies that quality of care services
might be crucial for tackling frequent use. Hospitals are advised to regularly
analyze their ED data in the EHR to better align resources.
