title: Utilization patterns of diagnostic imaging across the late life course: a population-based study in Ontario, Canada.
abstract: OBJECTIVE
  Due to the aging baby boom population, utilization rates of diagnostic imaging (i.e., X-ray, CT, and MRI scanning) have risen rapidly relative to other health services. The aim of this study is to investigate the utilization patterns of outpatient diagnostic imaging services (X-ray, CT, and MRI) across the late life course (65 years and older).
  
  
  METHODS
  A population-based retrospective cohort study was conducted for the period April 1, 2005, to March 31, 2006. All Ontario residents aged 65+ and eligible for government health insurance were included in the analysis.
  
  
  RESULTS
  Utilization of diagnostic imaging followed an inverted U-pattern: increasing with advancing age, peaking in the 80-84 age group for CT scans and in the 70-74 age group for MRI and X-rays, and then declining in the later years. Overall, females received significantly more X-rays than males (p < .01), but males received significantly more CT and MRI scans (p < .01). A small proportion of high-users of radiology services accounted for a large proportion of overall utilization. Finally, our analysis revealed that a disproportionately large proportion of high-users of MRI services were in the highest SES quintile. No SES differences were observed for X-ray or CT scans.
  
  
  CONCLUSIONS
  Population aging will lead to increased demand for healthcare services. Utilization of outpatient diagnostic imaging services is associated with age, gender, and SES. Given the increasing demand and the limited resources available, there may be a need for programs to target underserved populations to reduce remediable inequities. Whereas patient-level decisions regarding the use of diagnostic imaging are rightfully determined on the basis of clinical factors, allocation decisions should also be informed by the ethical principles of equity and fairness.
authors.affiliation: Primary Care Research Unit, Sunnybrook Health Sciences Centre, 2075 Bayview Avenue, Toronto, Ontario, Canada. li.wang@sunnybrook.ca
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.forename: Jason X
authors.initials: JX
authors.lastname: Nie
authors.forename: C Shawn
authors.initials: CS
authors.lastname: Tracy
authors.forename: Rahim
authors.initials: R
authors.lastname: Moineddin
authors.forename: Ross E G
authors.initials: RE
authors.lastname: Upshur
mesh_terms: D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D015331:Cohort Studies; D003952:Diagnostic Imaging / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007182:Income; D008297:Male; D009864:Ontario / Q000453:epidemiology; D012189:Retrospective Studies; D012424:Rural Population; D017678:Sex Distribution; D014505:Urban Population