title: Factors predicting patient use of the emergency department: a retrospective cohort study.
abstract: BACKGROUND
  Many studies have shown the tendency for people without a regular care provider or primary physician to make greater use of emergency departments. We sought to determine the effects of three aspects of care provided by primary physicians (physician specialty, continuity of care and comprehensiveness of care) on their patients' use of the emergency department.
  
  
  METHODS
  Using provincial administrative databases, we created a cohort of 367,315 adults aged 18 years and older. Participants were residents of urban areas of Quebec. Affiliation with a primary physician, the specialty of this physician (i.e., family physician v. specialist), continuity of care (as measured using the Usual Provider Continuity index) and comprehensiveness of care (i.e., number of complete annual examinations) were measured among participants (n = 311,701) who had visited a physician three or more times during a two-year baseline period. We used multivariable negative binomial regression to investigate the relationships between measures of care and the number of visits to emergency departments during a 12-month follow-up period.
  
  
  RESULTS
  Among participants under 65 years of age, emergency department use was higher for those not affiliated than for those affiliated with a family physician (incidence rate ratio [IRR] 1.11, 95% confidence interval [CI] 1.05-1.16) or a specialist (IRR 1.10, 95% CI 1.04-1.17). Among patients aged 65 years and older, having a specialist primary physician, as opposed to a family physician, predicted increased use of the emergency department (IRR 1.13, 95% CI 1.09-1.17). Greater continuity of care with a family physician predicted less use of the emergency department only among participants who made 25 or more visits to a physician during the baseline period. Greater continuity of care with a specialist predicted less use of the emergency department overall, particularly among participants with intermediate numbers of multimorbidities and admissions to hospital. Greater comprehensiveness of care by family physicians predicted less use of the emergency department.
  
  
  CONCLUSIONS
  Efforts to increase the proportion of adults affiliated with a family physician should target older adults, people who visit physicians more frequently and people with multiple comorbidities and admissions to hospital.
authors.affiliation: Department of Epidemiology, Biostatistics and Occupational Health, McGill University, and St. Mary's Research Centre, Montréal, Que. jane.mccusker@mcgill.ca
authors.forename: Jane
authors.initials: J
authors.lastname: McCusker
authors.forename: Pierre
authors.initials: P
authors.lastname: Tousignant
authors.forename: Roxane
authors.initials: R
authors.lastname: Borgès Da Silva
authors.forename: Antonio
authors.initials: A
authors.lastname: Ciampi
authors.forename: Jean-Frédéric
authors.initials: JF
authors.lastname: Lévesque
authors.forename: Alain
authors.initials: A
authors.lastname: Vadeboncoeur
authors.forename: Steven
authors.initials: S
authors.lastname: Sanche
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D015331:Cohort Studies; D003191:Comprehensive Health Care; D003266:Continuity of Patient Care; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005194:Family Practice; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011320:Primary Health Care; D011792:Quebec; D012044:Regression Analysis; D012189:Retrospective Studies; D013038:Specialization; D055815:Young Adult