Objective: The aim of the study was to evaluate use of physician assistants (PAs) and nurse practitioners (NPs) in US emergency departments (EDs).

Methods: We analyzed visits from the 1993 to 2005 National Hospital Ambulatory Medical Care Survey, seen by midlevel provider (MLP), and compared characteristics of MLP visits to those seen by physicians only.

Results: From 1993 to 2005, 5.2% (95% CI, 4.6%-5.8%) of US ED visits were seen by PAs and 1.7% (95% CI, 1.5%-2.0%) by NPs. During the study period, PA visits rose from 2.9% to 9.1%, whereas NP visits rose from 1.1% to 3.8% (both P(trend) < .001). Compared to physician only visits, those seen only by MLPs arrived by ambulance less frequently (6.0% vs 15%), had lower urgent acuity (37% vs 59%), and were admitted less often (3.0% vs 13%).

Conclusions: Midlevel provider use has increased in US EDs. Their involvement in some urgent visits and those requiring admission suggests that the role of MLPs extends beyond minor presentations.