Recent trends in hospital mortality of acute myocardial infarction--the Worcester Heart Attack Study. Have improvements been realized for all age groups?

BACKGROUND: While age-related differences in patterns of care for acute myocardial infarction have been demonstrated, temporal trends in clinical outcome for patients in different age groups have not been carefully examined.
METHODS: We analyzed data collected as part of an ongoing communitywide study of 5480 patients hospitalized with validated acute myocardial infarction in Worcester, Mass, during 7 selected years spanning a 15-year period (1975 through 1990). Patients were stratified into three age groups: less than 65 years (n = 2220), 65 through 74 years (n = 1595), and 75 years or older (n = 1665). Within each age group, the odds of in-hospital death were determined by study year, with adjustments for selected demographic, clinical, and hospital characteristics.
RESULTS: For patients less than age 65 years, the odds of dying during the acute hospital phase of myocardial infarction were reduced for all study years relative to the reference year (1975), reaching their lowest level in 1990 (adjusted odds ratio [OR], 0.16; 95% confidence interval [CI], 0.06 to 0.48). For patients aged 65 through 74 years, the odds of dying declined among patients hospitalized in 1978 (adjusted OR, 0.71; 95% CI, 0.39 to 1.29) and 1981 (adjusted OR, 0.36; 95% CI, 0.19 to 0.66) but remained essentially unchanged during the subsequent study years through 1990. For patients 75 years of age or older, the odds of dying declined through 1984 (adjusted OR, 0.42; 95% CI, 0.25 to 0.72) but increased over the following study years: 1986, 1988, and 1990.
CONCLUSIONS: While the risk of in-hospital death following acute myocardial infarction has recently declined for patients less than 65 years of age, improvements have not been realized for older age groups. Current patterns of management of acute myocardial infarction in older patients require reexamination.