title: Geography, Not Health System Affiliations, Determines Patients' Revisits to the Emergency Department.
abstract: To determine how frequently patients revisit the emergency department after an initial encounter, and to describe revisit capture rates for the same hospital, health system, and geographic region.
  
  
  
  Florida state data from January 1, 2010, to June 30, 2011, from the Healthcare Cost and Utilization Project.
  
  
  
  This is a retrospective cohort study of emergency department return visits among Florida adults over an 18-month period. We evaluated pairs of index and 30-day return emergency department visits and compared capture rates for hospital, health system, and geographic units.
  
  
  
  Data were obtained from the Agency for Healthcare Research and Quality's Healthcare Cost and Utilization Project and the American Hospital Association Annual Survey Database.
  
  
  
  Among 9,416,212 emergency department visits, 22.6 percent (2,124,441) were associated with a 30-day return. Seventy percent (1,477,772) of 30-day returns occurred to the same hospital. The 30-day return capture rates were highest within the same geographic area: county-level capture at 92 percent (IQR=86-96 percent) versus health system capture at 75 percent (IQR = 68-81 percent).
  
  
  
  Acute care utilization patterns are often independent of health system boundaries. Current population-based health care models that attribute patients to a single provider or health system may be strengthened by considering geographic patterns of acute care utilization.
authors.affiliation: Department of Emergency Medicine, Thomas Jefferson University, Philadelphia, PA.
authors.forename: Kristin L
authors.initials: KL
authors.lastname: Rising
authors.affiliation: Department of Emergency Medicine, Thomas Jefferson University, Philadelphia, PA.|Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, PA.
authors.forename: David N
authors.initials: DN
authors.lastname: Karp
authors.affiliation: Department of Internal Medicine, Thomas Jefferson University, Philadelphia, PA.
authors.forename: Rhea E
authors.identifier: 0000-0002-4157-3070
authors.initials: RE
authors.lastname: Powell
authors.affiliation: Graduate School of Education, University of Pennsylvania, Philadelphia, PA.
authors.forename: Timothy W
authors.initials: TW
authors.lastname: Victor
authors.affiliation: Department of Emergency Medicine, Thomas Jefferson University, Philadelphia, PA.|Emergency Care Coordination Center, US Department of Health & Human Services, Philadelphia, PA.
authors.forename: Brendan G
authors.initials: BG
authors.lastname: Carr
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D005431:Florida; D062305:Geographic Mapping; D006801:Humans; D008297:Male; D008875:Middle Aged; D010359:Patient Readmission / Q000706:statistics & numerical data*; D012111:Residence Characteristics; D012189:Retrospective Studies; D012959:Socioeconomic Factors; D013997:Time Factors; D014481:United States; D055815:Young Adult
keywords: Utilization of services; emergency medicine; geographic/spatial factors; health care organizations and systems; payment systems