Trends in Midlevel Provider Utilization in Emergency Departments from 1997 to 2006

Objectives: The objective was to quantify the expansion of midlevel provider (MLP) practice in U.S. emergency departments (EDs) over the past decade. Specifically, we sought to quantify the absolute number of patients seen by MLPs, the annual growth rate of patients seen by MLPs, and the expansion in the proportion of EDs using MLPs. Methods: Data were analyzed from the ED portion of the 10 most recent years (1997 to 2006) National Hospital Ambulatory Medical Care Survey (NHAMCS), a nationally representative survey of ED visits compiled by the Centers for Disease Control and Prevention (CDC). The main outcomes of interest were the proportion and absolute numbers of ED patients seen by MLPs during the 10-year study period. National estimates derived from sample weights are reported. In addition, a multivariate logistic regression model was created with "seen by midlevel provider" as the dependent variable to determine factors associated with being seen by a MLP. Results: Between 1997 and 2006, 8.23% (95% confidence interval [CI] = 7.31% to 9.15%) of ED patients were seen by a MLP. The proportion of ED patients seen by MLPs increased from 5.5% (95% CI = 3.8% to 7.1%) in 1997 to 12.7% (95% CI = 10.5% to 14.9%) in 2006 (13% annual growth). This corresponds to an increase in the number of ED patients seen by MLPs from 5.2 million in 1997 to 15.2 million in 2006. The proportion of hospitals using MLPs in the ED increased from 28.3% (95% CI = 22.4% to 34.1%) in 1997 to 77.2% (95% CI = 71.2% to 83.3%) in 2006 (17% annual growth). Slightly over half of MLP cases (54.9%; 95% CI = 49.1% to 60.7%) were also seen by staff physicians. On multivariate regression, younger patient age, non-southern geographic region, and triage acuity were associated with increased MLP use. Conclusions: The number of ED patients seen by MLPs has increased sharply, from 5.2 million in 1997 (5.5% of all ED cases) to 15.2 million in 2006 (12.7% of all ED cases). Similarly, the proportion of EDs reporting use of MLPs has increased from 28.3% in 1997 to 77.2% in 2006.