title: The relationship between trauma center volume and in-hospital outcomes.
abstract: BACKGROUND
  Increases in hospital volume are positively associated with improved surgical outcomes. However, in the trauma setting, studies have reported conflicting findings in regard to volume's effect on in-hospital mortality. This study investigates whether complications, failure-to-rescue (FTR), and mortality are influenced by trauma centers' average annual volume.
  
  
  METHODS
  We performed a retrospective cohort study that analyzed patient records included in the National Trauma Data Bank from years 2008-2010. We calculated risk-adjusted complication, FTR, and mortality rates for centers treating different volumes of patients. We also performed multilevel logistic regression modeling to examine the probability that patients treated at trauma centers with higher annual volumes would experience complication, FTR, and mortality while controlling for injury severity, type of injury, mechanism of trauma, age, gender, race, number of comorbidities, head injury, hypotension, and hospital clustering. Hospital characteristics including designation level, academic status, nonprofit status, safety-net status, and region were incorporated into the model.
  
  
  RESULTS
  Risk-adjusted complication, FTR, and mortality rates differed significantly across hospital volume quintiles. Regression analyses indicated that higher hospital volumes were significantly associated with a decreased likelihood of mortality for individual patient but not for complication or FTR.
  
  
  CONCLUSIONS
  Our findings suggest that higher trauma center volume is associated with improved mortality outcomes. However, the relationship between volume and FTR is more complex. Future research should address the question of determining optimal volume levels that lead to high provider experience, efficient resource usage, and low unintended consequences or outcomes.
authors.affiliation: Department of Surgery, Indiana University School of Medicine, Indianapolis, Indiana. Electronic address: terebell@iupui.edu.
authors.forename: Teresa M
authors.initials: TM
authors.lastname: Bell
authors.affiliation: Center for Health Innovation and Implementation Science, Indiana University School of Medicine, Indianapolis, Indiana; Eskenazi Health, Indianapolis, Indiana.
authors.forename: Karim C
authors.initials: KC
authors.lastname: Boustany
authors.affiliation: Department of Surgery, Indiana University School of Medicine, Indianapolis, Indiana.
authors.forename: Peter C
authors.initials: PC
authors.lastname: Jenkins
authors.affiliation: Department of Surgery, Indiana University School of Medicine, Indianapolis, Indiana.
authors.forename: Ben L
authors.initials: BL
authors.lastname: Zarzaur
mesh_terms: D000328:Adult; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014193:Trauma Centers / Q000706:statistics & numerical data*; D014481:United States