title: Mortality in medicare patients undergoing surgery in July in teaching hospitals.
abstract: OBJECTIVE
  To determine whether operative mortality rates at teaching hospitals in the United States are higher in July, the start of the academic year.
  
  
  BACKGROUND
  Surgical patients at teaching hospitals often worry about the involvement of inexperienced physician trainees in their care.
  
  
  METHODS
  This retrospective cohort study included all Medicare recipients undergoing 1 of 7 diverse inpatient procedures at teaching hospitals between 2003 through 2006 (N = 320,216). Teaching status was defined both by membership in the United States Council of Teaching Hospitals and by hospital ratio of trainees to beds. We compared operative mortality rates in July relative to all other months, adjusting for potentially confounding patient characteristics. The main outcome measure was operative mortality (before discharge or within 30 days of procedures).
  
  
  RESULTS
  Adjusted operative mortality rates were no higher in July than in other months combined for all procedures, including coronary artery bypass grafting, carotid endarterectomy, repair of nonruptured abdominal aortic aneurysms, colectomy, pancreatectomy, esophagectomy, and repair of hip fracture. Trend analysis revealed no significant monthly or seasonal variation in operative mortality rates.
  
  
  CONCLUSIONS
  Operative mortality rates do not decline as surgical trainees acquire more experience during the academic year. With respect to mortality, July is a safe month to have major surgery in teaching hospitals in the United States.
authors.affiliation: Department of Surgery, Michigan Surgical Collaborative for Outcomes Research and Evaluation, University of Michigan, Ann Arbor, Michigan 48109-0331, USA. englesbe@med.umich.edu
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Englesbe
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Fan
authors.forename: Onur
authors.initials: O
authors.lastname: Baser
authors.forename: John D
authors.initials: JD
authors.lastname: Birkmeyer
mesh_terms: D000368:Aged; D002983:Clinical Competence; D015331:Cohort Studies; D005260:Female; D017052:Hospital Mortality; D006784:Hospitals, Teaching / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D006278:Medicare / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D012307:Risk Factors; D012621:Seasons; D013514:Surgical Procedures, Operative / Q000401:mortality*; D014481:United States / Q000453:epidemiology