ED patients: how nonurgent are they? Systematic review of the emergency medicine literature.

Nonurgent visits to emergency departments (ED) are a controversial issue; they have been negatively associated with crowding and costs. We have conducted a critical review of the literature regarding methods for categorizing ED visits into urgent or nonurgent and analyzed the proportions of nonurgent ED visits. We found 51 methods of categorization. Seventeen categorizations conducted prospectively in triage areas were based on somatic complaint and/or vital sign collection. Categorizations conducted retrospectively (n = 34) were based on the diagnosis, the results of tests obtained during the ED visit, and hospital admission. The proportions of nonurgent ED visits varied considerably: 4.8% to 90%, with a median of 32%. Comparisons of methods of categorization in the same population showed variability in levels of agreement. Our review has highlighted the lack of reliability and reproducibility.