title: Methods for analyzing referral patterns.
abstract: OBJECTIVE
  To develop a sound method to identify patient and physician characteristics that influence specialty referrals.
  
  
  METHODS
  A retrospective cohort analysis of medical claims data from 1996 supplemented with surveys of primary care physicians.
  
  
  METHODS
  A 600-member independent practice association in southeastern Michigan that provided care for 90,000 members of an HMO.
  
  
  METHODS
  Five cohorts, each of 2,000 to 6,000 patients with diagnoses that could be referred to cardiologists, ophthalmologists, pulmonologists, orthopedists, or general surgeons.
  
  
  RESULTS
  The referral rates for the different cohorts ranged from 1% to 7%. The discriminatory ability of the multivariate logistic models (c-statistic) ranged from 0.66 to 0.79. The likelihood of referral was associated with the patient's diagnoses and medications and with the referring physician's age, years out of medical school, satisfaction with the specialty being referred to, and the importance of making or confirming a diagnosis.
  
  
  CONCLUSIONS
  Because these methods were not difficult to implement and the results were credible, we believe that other organizations should be able to use them.
authors.affiliation: St. Joseph Mercy Hospital, Ann Arbor, Mich., USA.
authors.forename: M E
authors.initials: ME
authors.lastname: Cowen
authors.forename: M W
authors.initials: MW
authors.lastname: Zodet
mesh_terms: D015331:Cohort Studies; D003625:Data Collection / Q000379:methods; D005194:Family Practice / Q000706:statistics & numerical data*; D005260:Female; D006279:Health Maintenance Organizations; D006801:Humans; D016015:Logistic Models; D008297:Male; D008824:Michigan; D008875:Middle Aged; D015999:Multivariate Analysis; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data; D012017:Referral and Consultation / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D011795:Surveys and Questionnaires