title: Hospital Readmissions Following Physician Call System Change: A Comparison of Concentrated and Distributed Schedules.
abstract: BACKGROUND
  Physician call schedules are a critical element for medical practice and hospital efficiency. We compared readmission rates prior to and after a change in physician call system at Sunnybrook Health Sciences Centre.
  
  
  METHODS
  We studied patients discharged over a decade (2004 through 2013) and identified whether or not each patient was readmitted within the subsequent 28 days. We excluded patients discharged for a surgical, obstetrical, or psychiatric diagnosis. We used time-to-event analysis and time-series analysis to compare rates of readmission prior to and after the physician call system change (January 1, 2009).
  
  
  RESULTS
  A total of 89,697 patients were discharged, of whom 10,001 (11%) were subsequently readmitted and 4280 died. The risk of readmission was increased by about 26% following physician call system change (9.7% vs 12.2%, P <.001). Time-series analysis confirmed a 26% increase in the readmission rate after call system change (95% confidence interval, 22%-31%; P <.001). The increase in readmission rate after call system change persisted across patients with diverse ages, estimated readmission risks, and medical diagnoses. The net effect was equal to 7240 additional patient days in the hospital following call system change. A modest increase was observed at a nearby acute care hospital that did not change physician call system, and no increase in risk of death was observed with increased hospital readmissions.
  
  
  CONCLUSIONS
  We suggest that changes in physician call systems sometimes increase subsequent hospital readmission rates. Further reductions in readmissions may instead require additional resources or ingenuity.
authors.affiliation: Department of Medicine, University of Toronto, Ont., Canada; Evaluative Clinical Sciences, Sunnybrook Research Institute, Toronto, Ont., Canada.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Yarnell
authors.affiliation: Department of Medicine, University of Toronto, Ont., Canada; Division of General Internal Medicine, University of Toronto, Ont., Canada.
authors.forename: Steven
authors.initials: S
authors.lastname: Shadowitz
authors.affiliation: Department of Medicine, University of Toronto, Ont., Canada; Evaluative Clinical Sciences, Sunnybrook Research Institute, Toronto, Ont., Canada; Division of General Internal Medicine, University of Toronto, Ont., Canada; Institute of Clinical Evaluative Sciences (ICES) in Ontario, Toronto, Canada; Institute for Health Policy Management and Evaluation, Toronto, Ont., Canada. Electronic address: dar@ices.on.ca.
authors.forename: Donald A
authors.initials: DA
authors.lastname: Redelmeier
mesh_terms: D000058:Accidental Falls / Q000706:statistics & numerical data; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D050723:Fractures, Bone / Q000453:epidemiology; D006302:Health Services Research; D006333:Heart Failure / Q000453:epidemiology; D006760:Hospitalization; D006761:Hospitals; D006801:Humans; D007388:Internal Medicine / Q000458:organization & administration*; D065186:Interrupted Time Series Analysis; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000453:epidemiology; D009369:Neoplasms / Q000453:epidemiology; D009864:Ontario; D010359:Patient Readmission / Q000706:statistics & numerical data*; D010561:Personnel Staffing and Scheduling / Q000458:organization & administration*; D010820:Physicians / Q000458:organization & administration*; D058996:Quality Improvement; D014552:Urinary Tract Infections / Q000453:epidemiology; D055815:Young Adult
keywords: Duty hours; General internal medicine; Health services research; Patient outcomes; Physician call schedules; Quality improvement; Readmissions