title: Distances to emergency department and to primary care provider's office affect emergency department use in children.
abstract: OBJECTIVE
  Patients of all ages use emergency departments (EDs) for primary care. Several studies have evaluated patient and system characteristics that influence pediatric ED use. However, the issue of proximity as a predictor of ED use has not been well studied. The authors sought to determine whether ED use by pediatric Medicaid enrollees was associated with the distance to their primary care providers (PCPs), distance to the nearest ED, and distance to the nearest children's hospital.
  
  
  METHODS
  This historical cohort study included 26,038 children age 18 and under, assigned to 332 primary care practices affiliated with a Medicaid health maintenance organization (HMO). Predictor variables were distance from the child's home to his or her PCP site, distance from home to the nearest ED, and distance from home to the nearest children's hospital. The outcome variable was each child's ED use. A negative binomial model was used to determine the association between distance variables and ED use, adjusted for age, sex, and race, plus medical and primary care site characteristics previously found to influence ED use. Distance variables were divided into quartiles to test for nonlinear associations.
  
  
  RESULTS
  On average, children made 0.31 ED visits/person/year. In the multivariable model, children living greater than 1.19 miles from the nearest ED had 11% lower ED use than those living within 0.5 miles of the nearest ED (risk ratio [RR] = 0.89, 95% CI = 0.81 to 0.99). Children living between 1.54 and 3.13 miles from their PCPs had 13% greater ED use (RR = 1.13, 95% CI = 1.03 to 1.24) than those who lived within 0.7 miles of their PCP.
  
  
  CONCLUSIONS
  Geographical variables play a significant role in ED utilization in children, confirming the importance of system-level determinants of ED use and creating the opportunity for interventions to reduce geographical barriers to primary care.
authors.affiliation: Department of Emergency Medicin, Oregon Health and Science University, Portland, OR, USA.
authors.forename: Annameika
authors.initials: A
authors.lastname: Ludwick
authors.forename: Rongwei
authors.initials: R
authors.lastname: Fu
authors.forename: Craig
authors.initials: C
authors.lastname: Warden
authors.forename: Robert A
authors.initials: RA
authors.lastname: Lowe
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D005843:Geography; D006297:Health Services Accessibility / Q000706:statistics & numerical data*; D006801:Humans; D007223:Infant; D008297:Male; D008329:Managed Care Programs / Q000706:statistics & numerical data*; D008484:Medicaid / Q000706:statistics & numerical data*; D015233:Models, Statistical; D011320:Primary Health Care; D014481:United States