title: Factors associated with patients who leave without being seen.
abstract: OBJECTIVE
  Patients who leave without being seen (LWBS) can be an indicator of patient satisfaction and quality for emergency departments (ED). The objective of this study was to develop a model to determine factors associated with patients who LWBS.
  
  
  METHODS
  A modified case-crossover design to determine the transient effects on the risk of acute events was used. Over a four-month period, time intervals when patients LWBS were matched (within two weeks), according to time of day and day of week, with time periods when patients did not LWBS. Factors considered were percentage of ED bed capacity, acuity of ED patients, length of stay of discharged patients in the ED, patients awaiting an admission bed in the ED, inpatient floor capacity, intensive care unit capacity, and the characteristics of the attending physician in charge. McNemar test, Wilcoxon signed-rank test, and conditional logistic regression analyses were used to determine significant variables.
  
  
  RESULTS
  Over the study period, there were 11,652 visits, of which 213 (1.8%) resulted in patients who LWBS. Measures of inpatient capacity were not associated with patients who LWBS and ED capacity was only associated when >100%. This association increased with increasing capacity. Other significant factors were older age (p < 0.01) and completion of an emergency medicine residency (p < 0.01) of the physician in charge. When factors were considered in a multivariate model, ED capacity >140% (odds ratio, 1.96; 95% confidence interval = 1.22 to 3.17) and noncompletion of an emergency medicine residency (odds ratio, 1.85; 95% confidence interval = 1.17 to 2.93) were most important.
  
  
  CONCLUSIONS
  ED capacity >100% is associated with patients who LWBS and is most significant at 140% capacity. ED capacity of 100% may not be a sensitive measure for overcrowding. Physician factors, especially emergency medicine training, also appear to be important when using LWBS as a quality indicator.
authors.affiliation: Division of Emergency Medicine, University of California-San Francisco, 505 Parnassus Avenue, San Francisco, CA 94143-0208, USA. skpol@itsa.ucsf.edu
authors.forename: Steven K
authors.initials: SK
authors.lastname: Polevoi
authors.forename: James V
authors.initials: JV
authors.lastname: Quinn
authors.forename: Nathan R
authors.initials: NR
authors.lastname: Kramer
mesh_terms: D016001:Confidence Intervals; D018592:Cross-Over Studies; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D006801:Humans; D007902:Length of Stay / Q000706:statistics & numerical data; D016015:Logistic Models; D015233:Models, Statistical; D015999:Multivariate Analysis; D016017:Odds Ratio; D017063:Outcome Assessment, Health Care; D017060:Patient Satisfaction / Q000706:statistics & numerical data; D012495:San Francisco; D016312:Treatment Refusal / Q000706:statistics & numerical data*