Regionalization and the Underuse of Angiography in the Veterans Affairs Health Care System as Compared with a Fee-for-Service System

BACKGROUND: Policies to concentrate or regionalize invasive procedures at high-volume medical centers are under active consideration. Such policies could improve outcomes among those who undergo procedures while increasing their underuse among those who never reach such centers. We compared the underuse of needed angiography after acute myocardial infarction in a traditional Medicare fee-for-service system with underuse in the regionalized Department of Veterans Affairs (VA) health care system. METHODS: We studied 1665 veterans from 81 VA hospitals and 19,305 Medicare patients from 1530 non-VA hospitals, all of whom were elderly men. We compared adjusted angiography use and one-year mortality among patients for whom angiography was rated as clinically needed. We compared underuse in models before and after controlling for the on-site availability of cardiac procedures. RESULTS: After adjustment for the need for angiography, underuse was present in both groups, but VA patients remained significantly less likely than Medicare patients to undergo angiography (43.9 percent vs. 51.0 percent; odds ratio, 0.75; 95 percent confidence interval, 0.57 to 0.96). After also controlling for on-site availability of cardiac procedures at the admitting hospital, we found no significant difference in the underuse of angiography among VA patients as compared with Medicare patients (odds ratio, 1.02; 95 percent confidence interval, 0.82 to 1.26) or in one-year mortality (odds ratio, 1.08; 95 percent confidence interval, 0.89 to 1.28). CONCLUSIONS: There is underuse of needed angiography after acute myocardial infarction in both the VA and Medicare systems, but the rate of underuse is significantly higher in the VA. These differences appear to be associated with limited on-site availability of cardiac procedures in the regionalized VA health care system. Further work should focus on how regionalization policies could be improved with effective referral and triage processes.