Changes in characteristics, risk factors, and in-hospital mortality among patients with acute myocardial infarction in the capital of China over 40 years.

•Age distributions of AMI patients showed a tendency towards younger and elder.•Urban and rural differences in prevalence of AMI gradually narrowed.•Prevalence of hypertension in AMI patients decreased over 40 years.•Prevalence of diabetes, prior stroke and myocardial infarction in AMI patients increased over 40 years.•In-hospital mortality of AMI has markedly decreased over 40 years.