Emergency Department Volume and Racial and Ethnic Differences in Waiting Times in the United States : Medical Care

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Emergency Department Volume and Racial and Ethnic Differences in Waiting Times in the United States

Sonnenfeld, Nancy PhD*; Pitts, Stephen R. MD; Schappert, Susan M. MA*; Decker, Sandra L. PhD*

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Medical Care 50(4):p 335-341, April 2012. | DOI: 10.1097/MLR.0b013e318245a53c



Racial and ethnic differences in emergency department (ED) waiting times have been observed previously.


We explored how adjusting for ED attributes, particularly visit volume, affected racial/ethnic differences in waiting time.

Research Design: 

We constructed linear models using generalized estimating equations with 2007–2008 National Hospital Ambulatory Medical Care Survey data.


We analyzed data from 54,819 visits to 431 US EDs.


Our dependent variable was waiting time, measured from arrival to time seen by physician, and was log transformed because it was skewed. Primary independent variables were individual race/ethnicity (Hispanic and non-Hispanic white, black, other) and ED race/ethnicity composition (covariates for percentages of Hispanics, blacks, and others). Covariates included patient age, triage assessment, arrival by ambulance, payment source, volume, region, and teaching hospital.


Geometric mean waiting times were 27.3, 37.7, and 32.7 minutes for visits by white, black, and Hispanic patients. Patients waited significantly longer at EDs serving higher percentages of black patients; per 25 point increase in percent black patients served, waiting times increased by 23% (unadjusted) and 13% (adjusted). Within EDs, black patients waited 9% (unadjusted) and 4% (adjusted) longer than whites. The ED attribute most strongly associated with waiting times was visit volume. Waiting times were about half as long at low-volume compared with high-volume EDs (P<0.001). For Hispanic patients, differences were smaller and less robust to model choice.


Non-Hispanic black patients wait longer for ED care than whites primarily because of where they receive that care. ED volume may explain some across-ED differences.

© 2012 Lippincott Williams & Wilkins, Inc.

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