title: Regional variations in health status.
abstract: BACKGROUND
  Knowledge about variations in the health status of patients seeking primary care in different parts of the United States is limited.
  
  
  OBJECTIVE
  To examine regional variations in the physical and mental health of patients receiving primary care in the largest integrated health care system in the United States which is operated by the Department of Veteran Affairs (VA).
  
  
  METHODS
  We performed a mailed, cross sectional survey of 54,844 patients who were enrolled in seven VA General Internal Medicine clinics.
  
  
  RESULTS
  Among the 30,690 patients who returned an initial set of screening questionnaires, the prevalence of common chronic conditions varied by as much as 60% among the seven clinics. Moreover, patients' general health (measured by the SF-36) also varied significantly in a pattern that mirrored the observed differences in the prevalence of chronic conditions. After adjustment for important comorbid illnesses and sociodemographic factors, geographic site accounted for a small percentage of the explained variance in patient assessed health status.
  
  
  CONCLUSIONS
  The substantial differences in the health of patients enrolled in different VA primary clinics have important implications for the evaluation of clinical performance and health outcomes. Most of these differences can be attributed to sociodemographic and comorbid factors.
authors.affiliation: Northwest Health Services Research and Development Center of Excellence, VA Puget Sound Health Care System, Seattle, Washington, USA. dau@u.washington.edu
authors.forename: D H
authors.initials: DH
authors.lastname: Au
authors.forename: M B
authors.initials: MB
authors.lastname: McDonell
authors.forename: D C
authors.initials: DC
authors.lastname: Martin
authors.forename: S D
authors.initials: SD
authors.lastname: Fihn
mesh_terms: D002908:Chronic Disease / Q000453:epidemiology*; D015897:Comorbidity; D003266:Continuity of Patient Care; D003430:Cross-Sectional Studies; D006304:Health Status; D006801:Humans; D016014:Linear Models; D008603:Mental Health; D015995:Prevalence; D012111:Residence Characteristics; D012959:Socioeconomic Factors; D014481:United States / Q000453:epidemiology; D014728:Veterans / Q000706:statistics & numerical data*