title: Execution of diagnostic testing has a stronger effect on emergency department crowding than other common factors: a cross-sectional study.
abstract: OBJECTIVE
  We compared the effects of execution of diagnostic tests in the emergency department (ED) and other common factors on the length of ED stay to identify those with the greatest impacts on ED crowding.
  
  
  METHODS
  Between February 2010 and January 2012, we conducted a cross-sectional, single-center study in the ED of a large, urban, teaching hospital in Japan. Patients who visited the ED during the study period were enrolled. We excluded (1) patients scheduled for admission or pharmaceutical prescription, and (2) neonates requiring intensive care transferred from other hospitals. Multivariate linear regression was performed on log-transformed length of ED stay in admitted and discharged patients to compare influence of diagnostic tests and other common predictors. To quantify the range of change in length of ED stay given a unit change of the predictor, a generalized linear model was used for each group.
  
  
  RESULTS
  During the study period, 55,285 patients were enrolled. In discharged patients, laboratory blood tests had the highest standardized β coefficient (0.44) among common predictors, and increased length of ED stay by 72.5 minutes (95% CI, 72.8-76.1 minutes). In admitted patients, computed tomography (CT) had the highest standardized β coefficient (0.17), and increased length of ED stay by 32.7 minutes (95% CI, 40.0-49.9 minutes). Although other common input and output factors were significant contributors, they had smaller standardized β coefficients in both groups.
  
  
  CONCLUSIONS
  Execution of laboratory blood tests and CT had a stronger influence on length of ED stay than other common input and output factors.
authors.affiliation: Department of Emergency Medicine, University of Fukui Hospital, Fukui, Japan.
authors.forename: Takahisa
authors.initials: T
authors.lastname: Kawano
authors.affiliation: Department of Primary Care and Emergency Medicine, Kyoto University Graduate School of Medicine, Kyoto city, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Nishiyama
authors.affiliation: Department of General Medicine, University of Fukui Hospital, Fukui, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Hayashi
mesh_terms: D000293:Adolescent; D000328:Adult; D003430:Cross-Sectional Studies; D003441:Crowding; D003955:Diagnostic Tests, Routine; D004636:Emergency Service, Hospital; D005260:Female; D006784:Hospitals, Teaching; D006801:Humans; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D013997:Time Factors; D055815:Young Adult