Differences in Short- and Long-Term Outcomes Among Older Patients With ST-Elevation Versus Non–ST-Elevation Myocardial Infarction With Angiographically Proven Coronary Artery Disease

Abstract

Background— Among older patients with acute myocardial infarction (MI), it remains uncertain whether there is a time-dependent difference in the risk of recurrent mortality and nonfatal cardiovascular and cerebrovascular events for those with ST-segment–elevation MI (STEMI) compared with those with non–ST-segment–elevation MI. Methods and Results— Older patients ≥65 years with acute MI and significant coronary artery disease identified with coronary angiography from the ACTION Registry-GWTG (Get With the Guidelines) were linked to Medicare claims data from 2007 to 2010. We examined the unadjusted cumulative incidence of each outcome studied from hospital discharge through 2 years with log-rank tests and then performed a piece-wise proportional hazards modeling with 2 time periods: discharge to 90 days and 90 days to 2 years. Among the 46 199 patients linked with Medicare data, 17 287 (37.4%) presented with STEMI. Through 2 years, the unadjusted cumulative incidence of all-cause mortality (16.0% versus 19.8%; P <0.001) and the composite outcome (21.9% versus 27.9%; P <0.001) was lower for STEMI patients. Within the first 90 days, unadjusted rates of mortality (5.5% versus 5.3%) and the composite outcome (7.9% versus 8.1%) were similar but diverged from 90 days to 2 years (mortality, 11.1% versus 15.4%; P <0.001; composite outcome, 15.2% versus 21.5%; P <0.001). After multivariable adjustment, the adjusted risks of mortality and the composite outcome through 90 days were higher for STEMI patients, whereas risks of mortality and the composite outcome were attenuated from 90 days through 2 years. Conclusions— Among older acute MI patients with angiographically confirmed coronary artery disease discharged alive, STEMI patients (compared with non–ST-segment–elevation MI patients) were found to have a lower frequency of unadjusted postdischarge mortality and composite cardiovascular and cerebrovascular outcomes through 2 years after hospital discharge. This analysis provides unique insight into differential short- and long-term risks of ischemic cardiovascular and cerebrovascular outcomes by MI classification among older MI patients with confirmed coronary artery disease surviving to hospital discharge.