Resource utilization in treatment of acute myocardial infarction: staff-model health maintenance organization versus fee-for-service hospitals. The MITI Investigators. Myocardial Infarction Triage and Intervention.
OBJECTIVE
This study sought to compare the use of invasive procedures and length of stay for patients admitted with acute myocardial infarction to health maintenance organization (HMO) and fee-for-service hospitals.


BACKGROUND
The HMOs have reduced costs compared with fee-for-service systems by reducing discretionary admissions and decreasing hospital length of stay. It has not been established whether staff-model HMO hospitals also reduce the rate of procedure utilization.


METHODS
Using data from a retrospective cohort, we performed univariate and multivariate comparisons of the use of cardiac procedures, length of stay and hospital mortality in 998 patients admitted to two staff-model HMO hospitals and 7,036 patients admitted to 13 fee-for-service hospitals between January 1988 and December 1992.


RESULTS
The odds of undergoing coronary angiography were 1.5 times as great for patients admitted to fee-for-service hospitals than for those admitted to HMO hospitals (odds ratio 1.5, 95% confidence interval [CI] 1.3 to 1.9). Similarly, the odds of undergoing coronary revascularization were two times greater in fee-for-service hospitals (odds ratio 2.0, 95% CI 1.6 to 2.5). However, higher utilization was strongly associated with the greater availability of on-site cardiac catheterization facilities in fee-for-service hospitals. The length of hospital stay, by contrast, was approximately 1 day shorter in the fee-for-service cohort (7.3 vs. 8.0 days, p < 0.05).


CONCLUSIONS
Physicians in staff-model HMO hospitals use fewer invasive procedures and longer lengths of stay to treat patients with acute myocardial infarction than physicians in fee-for-service hospitals. This finding, however, appears to be associated with the lack of on-site catheterization facilities at HMO hospitals.
Every
N R
NR
Northwest Health Services Research and Development Field Program, Seattle Veterans Affairs Medical Center, WA, USA.
Fihn
S D
SD
Maynard
C
C
Martin
J S
JS
Weaver
W D
WD
D000368:Aged; D000704:Analysis of Variance; D015986:Confounding Factors, Epidemiologic; D017023:Coronary Angiography / Q000191:economics / Q000706:statistics & numerical data*; D018588:Fee-for-Service Plans / Q000191:economics* / Q000706:statistics & numerical data; D005260:Female; D006279:Health Maintenance Organizations / Q000191:economics* / Q000706:statistics & numerical data; D006739:Hospital Administration / Q000191:economics*; D017052:Hospital Mortality; D006801:Humans; D007902:Length of Stay / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000401:mortality / Q000628:therapy*; D009204:Myocardial Revascularization / Q000191:economics / Q000706:statistics & numerical data*; D016017:Odds Ratio; D012189:Retrospective Studies; D014218:Triage; D014481:United States; D014861:Washington