Over the past decade, a large body of evidence has emerged demonstrating the prognostic significance of troponin as well as its use in tailoring therapeutic interventions. Little is known, however, regarding the association of troponin status with guideline-based therapies in older patients with acute myocardial infarction (AMI).
A nationwide sample of eligible Medicare beneficiaries 65 years or older, who were hospitalized with a primary discharge diagnosis of AMI from April 1998 to March 1999 or from July 2000 to June 2001, was evaluated. The analysis was restricted to patients with clinically confirmed AMI who underwent testing for both creatine kinase–myocardial band (CK-MB) and troponin. Results were assessed in 3 groups of patients based on biomarker status: those whose findings were positive for troponin only (hereinafter, troponin-only patients), those whose findings were positive for CK-MB only (hereinafter, CK-MB–only patients), and those whose findings were positive for both troponin and CK-MB (hereinafter, troponin/CK-MB patients). Then, the use of guideline-recommended care was compared for patients without contraindications to treatment across the 3 groups.
The final study sample included 33 096 patients (mean age, 77.6 years [range, 65-105 years]). The crude in-hospital mortality rate was highest for troponin-only patients (14%) and lowest for CK-MB–only patients (10%, P<.001). After adjusting for demographics, physician specialty, and hospital characteristics, CK-MB–only patients were more likely to receive aspirin (odds ratio [OR], 1.46; 95% confidence interval [CI], 1.28-1.65) and β-blocker (OR, 1.21; 95% CI, 1.08-1.34) within 24 hours of hospital arrival and aspirin on discharge (OR, 1.27; 95% CI, 1.08-1.49) compared with troponin-only patients. In addition, troponin/CK-MB patients were more likely to receive aspirin (OR, 1.55; 95% CI, 1.42-1.69) and β-blocker (OR, 1.22; 95% CI, 1.12-1.31) within 24 hours of arrival and on discharge compared with troponin-only patients (ORs, 1.31 [95% CI, 1.17-1.46] and 1.33 [95% CI, 1.15-1.52] for aspirin and β-blocker, respectively) .
Despite the known poor prognosis associated with troponin elevations in AMI, we demonstrate that guideline-based therapies are underused in older patients with AMI. Therefore, national efforts should focus on the unique characteristics of this high-risk patient population to improve the quality of care for older patients with AMI.