title: A community-based study of the use of chiropractic services.
abstract: BACKGROUND
  Little population-based information is available on the use of chiropractic services.
  
  
  METHODS
  We analyzed data from the RAND Health Insurance Experiment (HIE), a community-based study of the use of health services. Insurance claim forms for all fee-for-service patients who completed the study were examined for all visits coded as being seen by a chiropractor. Services provided and patient-specified symptoms were taken from these forms. Population-based use rates were calculated for each HIE site. Use rates and services were calculated separately for first visits and repeat visits.
  
  
  RESULTS
  There were 5,279 persons who contributed 19,021 person-years of exposure during the study; 395 different persons used 7,873 chiropractic services for a visit rate of 41 per 100 person-years and rate of use of 7.5 percent. Forty-two percent of all visits were for pain in the back. Spinal manipulation accounted for 61 percent of all services provided. Compared to non-users, users tended to be White, middle-aged, married, and high school educated. Seven-fold geographic variations in the use of chiropractic services were seen.
  
  
  CONCLUSIONS
  Chiropractors deliver a substantial amount of health care to the US population, and there are significant geographic variations in the rate and intensity of use of chiropractic services.
authors.affiliation: Department of Medicine, University of California Los Angeles 90024.
authors.forename: P G
authors.initials: PG
authors.lastname: Shekelle
authors.forename: R H
authors.initials: RH
authors.lastname: Brook
mesh_terms: D000293:Adolescent; D000328:Adult; D002684:Chiropractic; D005260:Female; D006801:Humans; D008297:Male; D008404:Massachusetts; D008875:Middle Aged; D009820:Ohio; D011446:Prospective Studies; D012959:Socioeconomic Factors; D013022:South Carolina; D014861:Washington