Variation in death rate after abdominal aortic aneurysmectomy in the United States: impact of hospital volume, gender, and age.
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.
Dimick
Justin B
JB
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.
Stanley
James C
JC
Axelrod
David A
DA
Kazmers
Andris
A
Henke
Peter K
PK
Jacobs
Lloyd A
LA
Wakefield
Thomas W
TW
Greenfield
Lazar J
LJ
Upchurch
Gilbert R
GR
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