title: The relationship between geographic variations and overuse of healthcare services: a systematic review.
abstract: OBJECTIVE
  To examine the relationship between overuse of healthcare services and geographic variations in medical care.
  
  
  METHODS
  Systematic Review.
  
  
  METHODS
  Articles published in Medline between 1978, the year of publication of the first framework to measure quality, and January 1, 2009.
  
  
  METHODS
  Four investigators screened 114,830 titles and 2 investigators screened all selected abstracts and articles for possible inclusion and extracted all data.
  
  
  METHODS
  We extracted data on rates of overuse in different geographic areas. We also extracted data on underuse, if available, for the same population in which overuse was measured.
  
  
  RESULTS
  Five papers examined the relationship between geographic variations and overuse of healthcare services. One study in 2008 compared the appropriateness of coronary angiography (CA) for acute myocardial infarction in high-cost areas versus low cost areas in the Medicare population and found largely similar rates of inappropriateness (12.2% vs. 16.2%). A study in 2000 using national data concluded that overuse of CA explained little of the geographic variations in the use of this procedure in the Medicare program. An older study of Medicare patients found similar rates of inappropriate use of CA (15% to 17% vs. 18%), endoscopy (15% vs. 18% 19%), and carotid endarterectomy (29% vs. 30%) in low-use and high-use regions. A small area reanalysis of data from this study of 3 procedures found no evidence of a relationship between inappropriate use of procedures and volume in 23 adjacent counties of California. Another 2008 study found that inappropriate chemotherapy for stage I cancer was less common in low-cost areas compared with high-cost areas (3.1% vs. 6.3%).
  
  
  CONCLUSIONS
  The limited available evidence does not lend support to the hypothesis that inappropriate use of procedures is a major source of geographic variations in intensity and/or costs of care. More research is needed to improve our understanding of the relationship between geographic variations and the quality of care.
authors.affiliation: Division of General Internal Medicine, University of California at San Francisco, CA, USA. salomeh.keyhani@ucsf.edu
authors.forename: Salomeh
authors.initials: S
authors.lastname: Keyhani
authors.forename: Raphael
authors.initials: R
authors.lastname: Falk
authors.forename: Tara
authors.initials: T
authors.lastname: Bishop
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Howell
authors.forename: Deborah
authors.initials: D
authors.lastname: Korenstein
mesh_terms: D017023:Coronary Angiography / Q000191:economics / Q000706:statistics & numerical data; D016894:Endarterectomy, Carotid / Q000191:economics / Q000706:statistics & numerical data; D016099:Endoscopy, Gastrointestinal / Q000191:economics / Q000706:statistics & numerical data; D005843:Geography; D017048:Health Care Costs / Q000706:statistics & numerical data; D006300:Health Services Misuse / Q000191:economics / Q000706:statistics & numerical data; D006801:Humans; D006278:Medicare / Q000191:economics / Q000706:statistics & numerical data; D011787:Quality of Health Care / Q000191:economics / Q000706:statistics & numerical data; D014481:United States