title: A population-based cohort study of ambulatory care service utilization among older adults.
abstract: OBJECTIVE
  Age-related effects on ambulatory care service utilization are not well understood. We aim to measure the utilization patterns of ambulatory health care services (i.e. family physician visits, specialist physician visits and emergency room visits) in the late life course (65 years and older).
  
  
  METHODS
  A population-based retrospective cohort study was conducted for the period 1 April 2005 to 31 March 2006. All Ontario, Canada, residents aged 65+ and eligible for government health insurance were included in the analysis.
  
  
  RESULTS
  This population-based cohort study demonstrates considerable increase in utilization rates and variability of ambulatory services as age increases. Variations in utilization were observed by gender as overall women were more likely to consult a family physician, and men more likely to visit specialists and the emergency room. A small group of high users, constituting 5.5% of the total population, accounted for 18.7% of total ambulatory visits. Finally, we report socio-economic status (SES) based disparity for specialist services in which high users were more likely to have higher SES.
  
  
  CONCLUSIONS
  There is increasing utilization and variability in ambulatory service utilization with increase in age. Further research is required to explain the gender and SES differences reported in this study.
authors.affiliation: Primary Care Research Unit, Sunnybrook Health Sciences Centre, Toronto, ON, Canada.
authors.forename: Jason X
authors.initials: JX
authors.lastname: Nie
authors.forename: Li
authors.initials: L
authors.lastname: Wang
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: D000368:Aged; D000369:Aged, 80 and over; D000554:Ambulatory Care Facilities / Q000706:statistics & numerical data*; D015331:Cohort Studies; D016208:Databases, Factual; D005260:Female; D006801:Humans; D008297:Male; D009313:National Health Programs; D009864:Ontario; D012189:Retrospective Studies