Decreasing mortality from acute myocardial infarction: effect of incidence and prognosis.

Coronary heart disease (CHD) mortality rates have declined for the past 25 years in most western countries. During the 1970s and early 1980s, a decline in incidence was the main factor in the decline in mortality, but more recently, improvements in treatment and prognosis have played a larger role. Most of the change is a result of improvements in the treatment of risk factors among patients with chronic CHD, while the treatment of acute myocardial infarction has contributed a smaller part. CHD mortality has consistently decreased more than incidence, which may have led to an increased prevalence of CHD. Simultaneously, the treatment practice patterns and possibly also clinical presentation of CHD has changed so that hospitalizations as a result of CHD diagnoses other than myocardial infarction have increased, while definite myocardial infarctions have decreased. Furthermore, the stabilizing rates of incident myocardial infarction combined with the aging population tend to increase the numbers of CHD patients. Therefore, the total burden of CHD to the community has decreased less than one would expect on the basis of age-standardized mortality rates. There is a need to re-emphasize primary prevention, since heavy reliance on expensive treatments for the post-war baby-boom generation presents a major concern for public health resources.