title: The more the better?: the impact of surgeon and hospital volume on in-hospital mortality following colorectal resection.
abstract: OBJECTIVE
  To determine the in-hospital mortality rates for patients undergoing colorectal resection for malignant or benign conditions, and to identify risk factors for in-hospital death, particularly the relationships with surgeon and hospital volume.
  
  
  BACKGROUND
  Although there is strong evidence that complex cancer operations are best performed at specialized high-volume centers and by high-volume surgeons, the relationship between surgeon and hospital volume and perioperative outcomes is less well defined for more common procedures such as colorectal resections, particularly for benign diseases.
  
  
  METHODS
  We obtained data from the Canadian Institute for Health Information Discharge Abstract Database on all adult patients who underwent colorectal resection between April 1, 2005 and March 31, 2006. We performed a logistic regression to identify variables associated with a higher likelihood of in-hospital death.
  
  
  RESULTS
  Twenty-one thousand seventy-four patients underwent colorectal resection, with the majority being elective (59.4%). Malignancy represented the most common indication for resection (56.8%), followed by diverticular disease (16.2%) and inflammatory bowel disease (7.1%). The overall in-hospital mortality rate among patients undergoing colorectal resection was 5.3%. Increased age (adjusted Odds Ratio [OR]: 1.97 per 10 years, P < 0.001), urgent operation (OR: 2.63, P < 0.001), indication for resection (P < 0.001), nature of the surgery (P < 0.001), and several comorbidities were all independently associated with an increased risk of death. Surgeons with higher volumes of colorectal resections achieved significantly lower mortality rates (OR: 0.92 per 20 cases/y, P = 0.003), corresponding to an adjusted mortality rate of 5.6% for surgeons in the bottom decile (1 case per year) compared with 4.5% for surgeons in the top decile (greater than 43 cases per year). Hospital volume was not associated with mortality (OR: 1.00 per 10 cases, P = 0.504).
  
  
  CONCLUSIONS
  This large, population-based study suggests that surgeons who perform high volumes of colorectal resections achieve lower in-hospital mortality rates than surgeons with low volumes, whereas the hospital volume does not influence mortality.
authors.affiliation: Department of Surgery, The University of Western Ontario, London, Canada. pjkarani@uwo.ca
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Karanicolas
authors.forename: Luc
authors.initials: L
authors.lastname: Dubois
authors.forename: Patrick H D
authors.initials: PH
authors.lastname: Colquhoun
authors.forename: Carol J
authors.initials: CJ
authors.lastname: Swallow
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Walter
authors.forename: Gordon H
authors.initials: GH
authors.lastname: Guyatt
mesh_terms: D000328:Adult; D000368:Aged; D002170:Canada / Q000453:epidemiology; D003082:Colectomy / Q000401:mortality* / Q000706:statistics & numerical data; D003108:Colonic Diseases / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D017558:Elective Surgical Procedures / Q000401:mortality / Q000706:statistics & numerical data; D005260:Female; D006276:Health Facility Size; D017052:Hospital Mortality; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D016526:Workload