How should age affect management of acute myocardial infarction? A prospective cohort study

Background About 75% of patients with acute myocardial infarction are older than 70 years, but patients in this age group are commonly treated less vigorously than younger patients. This differential treatment may partly reflect clinicians' misconceptions about the outlook of such patients, and the importance of age in clinical decisions. We examined how age does and should affect the management of patients and risk stratification in acute myocardial infarction. Methods In this prospective cohort study, we recruited 1225 consecutive patients admitted with acute myocardial infarction to a district general hospital in east London. The primary endpoint was death. We used tabulation and regression methods to analyse the association between age group and clinical variables. Findings Patients aged 70 years or older took a longer time to arrive in hospital and were less likely to receive thrombolysis or discharge beta-blockers than patients younger than 60 years: odds ratio 0.63 (95% CI 9.45-0.88) for thrombolysis and 0.25 (0.16-0.37) for beta-blockade, adjusted for sex, diabetes, previous acute myocardial infarction, Q wave infarction, and left-ventricular failure. Left-ventricular failure was the strongest independent predictor of death within 1 year of infarction with a hazard ratio of 4.76 (3.53-6.43), adjusted for age, sex, diabetes, and Q wave infarction. Patients aged 70 years or older without left-ventricular failure had significantly better survival at 1 year after acute myocardial infarction than patients under 60 years with left-ventricular failure. 70.8% (62.2-78.2) of the older patients who survived to hospital discharge were still alive 3 years later. Interpretation Elderly patients with acute myocardial infarction were treated less vigorously than younger patients. The prognosis of acute myocardial infarction, however, was substantially affected by the development of left-ventricular failure and other clinical indices, such that many older patients had a better outlook than younger patients with adverse clinical factors. In planning risk-based management, consideration of age independently of clinical status is inappropriate.