title: Primary Care Physician Panel Size and Quality of Care: A Population-Based Study in Ontario, Canada.
abstract: OBJECTIVE
  The purpose of this study was to determine the relationship between the number of patients under a primary care physician's care (panel size) and primary care quality indicators.
  
  
  METHODS
  We conducted a cross-sectional, population-based study of fee-for-service and capitated interprofessional and non-interprofessional primary health care practices in Ontario, Canada between April 2008 and March 2010, encompassing 4,195 physicians with panel sizes ≥1,200 serving 8.3 million patients. Data was extracted from multiple linked, health-related administrative databases and covered 16 quality indicators spanning 5 dimensions of care: access, continuity, comprehensiveness, and evidence-based indicators of cancer screening and chronic disease management.
  
  
  RESULTS
  The likelihood of being up-to-date on cervical, colorectal, and breast cancer screening showed relative decreases of 7.9% (P <.001), 5.9% (P = .01), and 4.6% (P <.001), respectively, with increasing panel size (from 1,200 to 3,900). Eight chronic care indicators (4 medication-based and 4 screening-based) showed no significant association with panel size. The likelihood of individuals with a new diagnosis of congestive heart failure having an echocardiogram, however, increased by a relative 8.1% (P <.001) with higher panel size. Increasing panel size was also associated with a 10.8% relative increase in hospitalization rates for ambulatory-care-sensitive conditions (P = .04) and a 10.8% decrease in non-urgent emergency department visits (P = .004). Continuity was highest with medium panel sizes (P <.001), and comprehensiveness had a small decrease (P = .03) with increasing panel size.
  
  
  CONCLUSIONS
  Increasing panel size was associated with small decreases in cancer screening, continuity, and comprehensiveness, but showed no consistent relationships with chronic disease management or access indicators. We found no panel size threshold above which quality of care suffered.
authors.affiliation: Department of Family Medicine, University of Ottawa, Canada C.T. Lamont Primary Health Care Research Centre, Bruyère Research Institute, Ottawa, Canada Institute of Population Health, University of Ottawa, Canada Department of Epidemiology and Community Medicine, University of Ottawa, Canada Institute of Clinical Evaluative Sciences, Ottawa, Canada sdahrouge@bruyere.org.
authors.forename: Simone
authors.initials: S
authors.lastname: Dahrouge
authors.affiliation: Department of Family Medicine, University of Ottawa, Canada C.T. Lamont Primary Health Care Research Centre, Bruyère Research Institute, Ottawa, Canada Institute of Population Health, University of Ottawa, Canada Department of Epidemiology and Community Medicine, University of Ottawa, Canada.
authors.forename: William
authors.initials: W
authors.lastname: Hogg
authors.affiliation: Institute of Clinical Evaluative Sciences, Ottawa, Canada Ottawa Hospital Research Institute, Ottawa, Canada.
authors.forename: Jaime
authors.initials: J
authors.lastname: Younger
authors.affiliation: Department of Family Medicine, University of Ottawa, Canada C.T. Lamont Primary Health Care Research Centre, Bruyère Research Institute, Ottawa, Canada.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Muggah
authors.affiliation: Southern Academic Primary Care Research Unit. School of Primary Health Care, Monash University, Clayton, Australia.
authors.forename: Grant
authors.initials: G
authors.lastname: Russell
authors.affiliation: Institute for Clinical Evaluative Sciences, Toronto, Canada Department of Family and Community Medicine, University of Toronto, Canada Department of Family and Community Medicine, St. Michael's Hospital, Toronto, Canada Centre for Research on Inner City Health, St. Michael's Hospital, Toronto, Canada.
authors.forename: Richard H
authors.initials: RH
authors.lastname: Glazier
mesh_terms: D002908:Chronic Disease; D003191:Comprehensive Health Care / Q000458:organization & administration / Q000592:standards* / Q000706:statistics & numerical data; D003266:Continuity of Patient Care / Q000592:standards / Q000706:statistics & numerical data; D003430:Cross-Sectional Studies; D016208:Databases, Factual; D019468:Disease Management; D055088:Early Detection of Cancer / Q000706:statistics & numerical data; D018588:Fee-for-Service Plans; D005260:Female; D006297:Health Services Accessibility / Q000592:standards / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D009864:Ontario; D011320:Primary Health Care / Q000458:organization & administration / Q000592:standards* / Q000706:statistics & numerical data; D019984:Quality Indicators, Health Care
keywords: panel size; primary health care; quality indicators; workload