title: Variation in death rate after abdominal aortic aneurysmectomy in the United States: impact of hospital volume, gender, and age.
abstract: OBJECTIVE
  To determine whether high-volume hospitals (HVHs) have lower in-hospital death rates after abdominal aortic aneurysm (AAA) repair compared with low-volume hospitals (LVHs).
  
  
  BACKGROUND
  Select statewide studies have shown that HVHs have superior outcomes compared with LVHs for AAA repair, but they may not be representative of the true volume-outcome relationship for the entire United States.
  
  
  METHODS
  Patients undergoing repair of intact or ruptured AAAs in the Nationwide Inpatient Sample (NIS) for 1996 and 1997 were included (n = 13,887) for study. The NIS represents a 20% stratified random sample representative of all U.S. hospitals. Unadjusted and case mix-adjusted analyses were performed.
  
  
  RESULTS
  The overall death rate was 3.8% for intact AAA repair and 47% for ruptured AAA repair. For repair of intact AAAs, HVHs had a lower death rate than LVHs. The death rate after repair of ruptured AAA was also slightly lower at HVHs. In a multivariate analysis adjusting for case mix, having surgery at an LVH was associated with a 56% increased risk of in-hospital death. Other independent risk factors for in-hospital death included female gender, age older than 65 years, aneurysm rupture, urgent or emergent admission, and comorbid disease.
  
  
  CONCLUSIONS
  This study from a representative national database documents that HVHs have a significantly lower death rate than LVHs for repair of both intact and ruptured AAA. These data support the regionalization of patients to HVHs for AAA repair.
authors.affiliation: Section of Vascular Surgery, Department of Surgery, University of Michigan Medical Center, Ann Arbor, Michigan, and Division of Vascular Surgery, Wayne State University School of Medicine, Detroit, Michigan, USA.
authors.forename: Justin B
authors.initials: JB
authors.lastname: Dimick
authors.forename: James C
authors.initials: JC
authors.lastname: Stanley
authors.forename: David A
authors.initials: DA
authors.lastname: Axelrod
authors.forename: Andris
authors.initials: A
authors.lastname: Kazmers
authors.forename: Peter K
authors.initials: PK
authors.lastname: Henke
authors.forename: Lloyd A
authors.initials: LA
authors.lastname: Jacobs
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Wakefield
authors.forename: Lazar J
authors.initials: LJ
authors.lastname: Greenfield
authors.forename: Gilbert R
authors.initials: GR
authors.lastname: Upchurch
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D017544:Aortic Aneurysm, Abdominal / Q000209:etiology / Q000401:mortality* / Q000601:surgery*; D001019:Aortic Rupture / Q000209:etiology / Q000401:mortality* / Q000601:surgery*; D005260:Female; D006742:Hospital Bed Capacity / Q000706:statistics & numerical data*; D017052:Hospital Mortality; D006801:Humans; D007902:Length of Stay / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D010043:Outcome and Process Assessment, Health Care; D012307:Risk Factors; D012737:Sex Factors; D014481:United States