National trends in CT use in the emergency department: 1995-2007.
OBJECTIVE
To identify nationwide trends and factors associated with the use of computed tomography (CT) in the emergency department (ED).


METHODS
This study was exempt from institutional review board approval. Data from the 1995-2007 National Hospital Ambulatory Medical Care Survey were used to evaluate the numbers and percentages of ED visits associated with CT. A mean of 30 044 visits were sampled each year. Data were also subcategorized according to multiple patient and hospital characteristics. The Rao-Scott χ(2) test was performed to determine whether CT use was similar across subpopulations. Data were evaluated according to exponential and logistic growth models.


RESULTS
From 1995 to 2007, the number of ED visits that included a CT examination increased from 2.7 million to 16.2 million, constituting a 5.9-fold increase and a compound annual growth rate of 16.0%. The percentage of visits associated with CT increased from 2.8% to 13.9%, constituting a 4.9-fold increase and a compound annual growth rate of 14.2%. The exponential growth model provided the best fit for the trend in CT use. CT use was greater in older patients, white patients, patients admitted to the hospital, and patients at facilities in metropolitan regions. By the end of the study period, the top chief complaints among those who underwent CT were abdominal pain, headache, and chest pain. The percentage of patient visits associated with CT for all evaluated chief complaints increased-most substantially among those who underwent CT for flank, abdominal, or chest pain.


CONCLUSIONS
Use of CT has increased at a higher rate in the ED than in other settings. The overall use of CT had not begun to taper by 2007.
Department of Radiology, Cincinnati Children’s Hospital Medical Center, 3333 Burnet Ave, MLC 5031, Cincinnati, OH 45229, USA. david.larson@cchmc.org
David B
DB
Larson
Lara W
LW
Johnson
Beverly M
BM
Schnell
Shelia R
SR
Salisbury
Howard P
HP
Forman
D016009:Chi-Square Distribution; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D019538:Health Care Surveys; D006801:Humans; D016015:Logistic Models; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data*; D014481:United States