Sequential events contributing to variations in cardiac revascularization rates.

Numerous studies have demonstrated the importance of race, payor, and gender in determining the use of cardiac services, including revascularization procedures (bypass surgery and angioplasty). However, there has been less investigation into where and when in the process of care differences in utilization arise. In this report, the authors examined the sequence of events leading to the use of revascularization procedures, identifying four phases of care (prehospital, intrahospital, interhospital, and posthospital). Following a cohort of 5857 patients admitted to California hospitals with acute myocardial infarction in 1991, the authors found differences in treatment probabilities during nearly every phase for different racial and payor groups. For example, compared with patients who are uninsured, patients with private insurance were more likely to be admitted initially to a hospital offering revascularization (adjusted odds ratio [OR] = 1.40, 95% confidence interval [CI] 1.30 to 1.51). Moreover, once admitted to such a hospital, private patients were more likely to undergo revascularization (adjusted OR = 2.30; 95% CI 1.80 to 2.94). They were also more likely to undergo transfer to receive revascularization (adjusted OR = 1.22; 95% CI 1.03 to 1.45), and to be readmitted for revascularization (adjusted OR = 1.60; 95% CI 1.13 to 2.27). Previously reported discrepancies in service use represent the cumulative effects of multiple phases during which different racial and payor groups experience different processes of care.