title: Utilisation of coronary angiography after acute myocardial infarction in Ontario over time: have referral patterns changed?
abstract: OBJECTIVE
  To examine how physicians in Ontario, Canada, have altered their referral patterns for coronary angiography after acute myocardial infarction (AMI) over time.
  
  
  METHODS
  Retrospective analysis of multilinked administrative data.
  
  
  METHODS
  Province of Ontario, Canada.
  
  
  METHODS
  146 365 Ontario AMI patients hospitalised between 1 April 1992 and 31 March 1999.
  
  
  METHODS
  Utilisation trends of coronary angiography among all patients, as well as within six subgroups: elderly (versus young), women (versus men), high (versus low) risk of 30 day mortality, high (versus low) socioeconomic status, cardiology (versus non-cardiology) attending physician specialty, and hospitals with (versus without) onsite revascularisation capacity. Cox proportional hazard models were adjusted for variations in patient, physician, and hospital characteristics over time.
  
  
  RESULTS
  Angiography rates in Ontario increased from 23.2% in 1992 to 35.5% in 1999 (p < 0.0001). Increases in utilisation of coronary angiography were most pronounced among the elderly (12.4-24.3% v 39.3-54.4% for non-elderly patients, p < 0.0001), the affluent (24.6-38.7% v 22.0-32.3% for less affluent patients, p = 0.01), and those tended to by cardiologists (32.0-47.1% v 20.3-30.1% for non-cardiology attending specialties, p < 0.0001) after adjusting for changes in baseline patient, physician, and hospital characteristics over time.
  
  
  CONCLUSIONS
  Despite universal health care availability, not all patients benefited equally from increases in service capacity for coronary angiography after AMI in Ontario. Wider implementation of data monitoring and explicit management systems may be required to ensure that appropriate utilisation of cardiac services is allocated to patients who are most in need.
authors.affiliation: Division of Cardiology, Schulich Heart Centre, Sunnybrook and Women's College Health Sciences Centre and the University of Toronto, Toronto, Ontario, Canada.
authors.forename: Y
authors.initials: Y
authors.lastname: Khaykin
authors.forename: P C
authors.initials: PC
authors.lastname: Austin
authors.forename: J V
authors.initials: JV
authors.lastname: Tu
authors.forename: D A
authors.initials: DA
authors.lastname: Alter
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D017023:Coronary Angiography / Q000706:statistics & numerical data* / Q000639:trends; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging* / Q000401:mortality; D009864:Ontario / Q000453:epidemiology; D010818:Practice Patterns, Physicians' / Q000639:trends*; D016016:Proportional Hazards Models; D012017:Referral and Consultation / Q000706:statistics & numerical data / Q000639:trends*; D012189:Retrospective Studies; D016019:Survival Analysis