Improvement in long-term survival among patients hospitalized with acute myocardial infarction, 1970 to 1980. The Minnesota Heart Survey.

The mortality rate associated with coronary heart disease in the United States has declined steadily since 1968, but the reasons for this favorable trend have not been completely elucidated. In particular, it is not clear to what extent the decline reflects decreasing incidence as opposed to improved survival. To assess whether improved survival after myocardial infarction has contributed to the decline, the Minnesota Heart Survey compared the four-year survival rate in patients discharged with a diagnosis of acute myocardial infarction from hospitals in the Twin Cities area in 1970 and 1980. After adjustment for clinical characteristics related to outcome, the survival rate among patients with a definite myocardial infarction was significantly higher in the 1980 than in the 1970 group. The four-year survival for men was 35 percent better in the 1980 than in the 1970 group (95 percent confidence interval, 21 to 50 percent), and for women it was 27 percent better (95 percent confidence interval, 1 to 46 percent). Improvement in survival during the period of hospitalization accounted for 70 percent of the overall gain in survival between 1970 and 1980 in men and for virtually all of the gain in women. We conclude that improved long-term survival among patients with acute myocardial infarction has made an important contribution to the decline in mortality from coronary disease.