Effect of Age on the Use of Evidence-Based Therapies
Background: Previous studies have documented an underuse of evidence-based therapies in patients with acute myocardial infarction (AMI). However, many of these studies failed to consider contraindications to therapy, the effect of age (ie, elderly vs non-elderly patients) on use, or both. The objective of this study was to determine whether elderly patients are less likely than non-elderly patients to receive evidence-based AMI treatments, both before and after the consideration of contraindications to therapy.
Methods: A retrospective chart review of a random sample of 5131 patients with AMI who were admitted to 1 of 44 hospitals in Ontario was conducted for the fiscal years 1994 to 1996. Using the Canadian Cardiovascular Research Team (CCORT)/Canadian Cardiovascular Society (CCS) Quality Indicators for AMI Care, we classified patients as being eligible or ideal (ie, no contraindications to treatment) candidates to receive aspirin, β-blockers, thrombolysis, angiotensin-converting enzyme inhibitors (ACEIs), or statins or to undergo lipid profiling. The proportions of eligible and ideal patients who received treatment were calculated, and the latter were compared with benchmarks.
Results: The median age of the cohort was 69 years; 63% were of the patients were aged ≥65 years. There was underperformance of prescribing treatments in ideal candidates relative to benchmarks (eg, aspirin at discharge: 78.6% vs 90% benchmark). The odds of ideal (ie, no contraindications) elderly candidates receiving various evidence-based AMI treatments were consistently less than that of non-elderly patients with AMI, with the exception of ACEIs at discharge (odds ratio, 1.46; 95% CI, 1.22-1.74).
Conclusions: Despite adjustments for contraindications to therapy, the underuse of AMI treatments, particularly in elderly patients, was found.

Elderly people, (ie, aged ≥65 years) comprise 13% of the Canadian population, and this number is expected to rise in the future. Also expected to rise is the incidence of cardiovascular disease in elderly patients, of which acute myocardial infarction (AMI) accounts for 8.9% to 11.6% of all cardiovascular-related deaths. According to 1997 data, 82.7% of all AMI deaths in Canada occurred in elderly people. Thus, particular attention is warranted for this patient population.

The benefit of evidence-based treatments, including aspirin, thrombolytics, β-blockers, angiotensin-converting enzyme inhibitors (ACEIs), and statins, in decreasing AMI-associated morbidity and mortality is likely the greatest in patients who are at high risk for AMI, such as elderly patients. However, it is uncertain whether elderly patients receive these treatments at optimal rates.

Previous quality of care studies, most of which were conducted in the United States, have documented the underuse of evidence-based treatments for AMI in elderly (Medicare) patients, even after controlling for contraindications to therapy. However, few studies exist that compare the use of such treatments in elderly and non-elderly patients (ie, <65 years old) for AMI. Because elderly patients may be more likely to have contraindications to therapy, studies that adjust for these contraindications are needed to make inferences about whether elderly patients receive the same quality of care as non-elderly patients.

The purpose of this study was to test the hypothesis that elderly patients are less likely to receive evidence-based AMI treatments than non-elderly patients, both before and after contraindications to therapy are considered. A detailed clinical database of a cohort of patients with AMI in the province of Ontario was used for this purpose.