Background Considerable variability exists in the use of cardiac procedures
for patients with heart disease. One cause for this variability is the ava
ilability of local facilities to perform these procedures. This study was i
nitiated to identify health system features that are related to rates of ca
theterization, percutaneous coronary angioplasty, and coronary artery bypas
s graft surgery in the Veterans Affairs health care system in which structu
red referral systems are intended to compensate for variation in local reso
urce availability
Methods Medical records of 30,901 patients admitted to a Veterans Affairs m
edical center with coronary artery disease were analyzed. Odds ratios (OR)
and 95% confidence intervals (CI) for undergoing each procedure, based on c
linical variables (age, sex, race, coronary artery disease type, and a comp
uted comorbidity score), and local Veterans Affairs facility features (geog
raphic region, primary service area size, and hospital complexity) were est
imated by logistic regression.
Results Regression models demonstrated significant associations between the
odds of undergoing each procedure and medical center geographic and comple
xity features, after adjustment for clinical variables. Associations includ
ed the presence of a cardiac catheterization laboratory For undergoing cath
eterization (OR 1.86, CI 1.76 to 1.95) and the presence of a cardiac surgic
al program for angioplasty (OR 1.46, CI 1.36 to 1.57) and bypass grafting (
OR 1.43, CI 1.34 to 1.53). Including health system variables in addition to
clinical variables in the regression models improved the discriminating ab
ility of the models by 44.2% to 51.4%.
Conclusions Geographic location and the complexity of the local Veterans Af
fairs hospital are important determinants of the use of cardiac procedures
in the Veterans Affairs health care system, even though referral networks a
re intended to correct for local differences in hospital complexity.