STEMI confers lower unadjusted risk for poor outcomes than non-STEMI in older patients with CAD
In a cohort of older patients presenting with acute MI with significant CAD and discharged alive, patients with STEMI displayed a lower frequency of unadjusted mortality and composite CV and cerebrovascular outcomes at 2 years compared with patients with non-STEMI, according to a new study.
However, after multivariable adjustment, those with STEMI had higher risk for poor outcomes at 90 days and similar risk from 90 days to 2 years compared with those with non-STEMI, according to the researchers.
Amit N. Vora, MD, MPH, from the Duke Clinical Research Institute, Duke University Medical Center, Durham, North Carolina, and colleagues studied 46,199 patients aged 65 years or older with acute MI and significant CAD identified with coronary angiography from the ACTION Registry-GWTG (Get With the Guidelines) linked to Medicare claims data from 2007 to 2010. From that cohort, 17,287 patients (37.4%) presented with STEMI.
Amit N. Vora
The outcomes of interest were all-cause mortality, rehospitalization for MI, rehospitalization for stroke and a composite of all three.
The researchers analyzed the unadjusted cumulative incidence of each outcome from hospital discharge at 2 years using log-rank tests, and also performed proportional hazards modeling using two periods — discharge to 90 days, and 90 days to 2 years.
Through 2 years, patients with STEMI compared with patients with non-STEMI had a lower unadjusted cumulative incidence of all-cause mortality (16% vs. 19.8%, P < .001) and the composite outcome (21.9% vs. 27.9%, P < .001).
In the first 90 days, rates for mortality (STEMI, 5.5%; non-STEMI, 5.3%; P = .18) and the composite outcome (STEMI, 7.9%; non-STEMI, 8.1%; P = .52) did not differ. However, from 90 days to 2 years, mortality (11.1% vs. 15.4%, P < .001) and the composite outcome (15.2% vs. 21.5%, P < .001) were lower in those with STEMI, Vora and colleagues found.
However, after multivariable adjustment, compared with patients with non-STEMI, those with STEMI were at increased risk for all-cause mortality (adjusted HR = 1.52; 95% CI, 1.38-1.68) and the composite outcome (adjusted HR = 1.39; 95% CI, 1.29-1.5) at 90 days, and were at slightly elevated risk for mortality (adjusted HR = 1.1; 95% CI, 1.02-1.18) and at no additional risk for the composite outcome (adjusted HR = 1.01; 95% CI, 0.95-1.08) from 90 days to 2 years.
More data needed
“There are several possibilities for the differential outcomes we observed by MI classification,” the researchers wrote. “In our study population, non-STEMI patients were found to have a greater likelihood of prior ischemic events, prior revascularization procedures, prior [HF], comorbidities and multivessel disease on angiography compared with STEMI patients. ...
“Our study also highlights the importance of studying long-term outcomes among an elderly population of patients with acute MI,” they wrote. “Elderly patients are typically underrepresented in clinical trials, and there is a paucity of high-quality data to inform practice guidelines in this population.” – by James Clark
Disclosure: Vora reports no relevant financial disclosures. Please see the full study for a list of all other researchers’ relevant financial disclosures.