title: Continued rise in the use of mid-level providers in US emergency departments, 1993-2009.
abstract: BACKGROUND
  Emergency department (ED) visits in the US have risen dramatically over the past 2 decades. In order to meet the growing demand, mid-level providers (MLPs) - both physician assistants (PAs) and nurse practitioners (NPs) - were introduced into emergency care. Our objective was to test the hypothesis that MLP usage in US EDs continues to rise.
  
  
  RESULTS
  We analyzed ED data from the National Hospital Ambulatory Medical Care Survey to identify trends in ED visits seen by MLPs. We also compared MLP-only visits (defined as visits where the patient was seen by a MLP without being seen by a physician) with those seen by physicians only. During 1993 to 2009, 8.4% (95%CI, 7.6-9.2%) of all US ED visits were seen by MLPs. These summary data include marked changes in MLP utilization: PA visits rose from 2.9% to 9.9%, while NP visits rose from 1.1% to 4.7% (both Ptrend < 0.001). Together, MLP visits accounted for almost 15% of 2009 ED visits and 40% of these were seen without involvement of a physician. Compared to physician only visits, those seen by MLPs only were less likely to arrive by ambulance (16% vs 6%) and be admitted (14% vs 3%).
  
  
  CONCLUSIONS
  Mid-level provider use is rising in US EDs. By 2009, approximately one in seven visits involved MLPs, with PAs managing twice as many visits as NPs. Although patients seen by MLPs only are generally of lower acuity, these nationally representative data confirm that MLP care extends beyond minor presentations.
authors.affiliation: Department of Emergency Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA. dbrown2@partners.org.
authors.forename: David F M
authors.initials: DF
authors.lastname: Brown
authors.forename: Ashley F
authors.initials: AF
authors.lastname: Sullivan
authors.forename: Janice A
authors.initials: JA
authors.lastname: Espinola
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Camargo