Recent morbidity trends in myocardial infarction in Japan: investigation of death certificates and the survival rates at coronary care units.

Abstract

To elucidate recent trends in the mortality and morbidity of myocardial infarction (MI), we investigated death certificates and changes in the survival rate of MI patients at coronary care units (CCUs), which may affect the death rates. For all cases of MI, acute heart failure (AHF), heart failure (HF) as underlying cause, and hypertension as underlying cause with HF or AHF (categorized as hypertensive heart disease) on death certificates in two rural and two urban populations between 1981 and 1984, medical records were reviewed and case histories obtained from interviews with patients' families to validate the diagnosis. The number of MI deaths on the death certificates was not underestimated because some MI deaths were misdiagnosed as AHF, HF and hypertensive heart disease and some MI death certificates were misdiagnosed. Survival of MI patients at CCUs improved in several major cities, Tokyo, Osaka, Wakayama and Asahikawa between 1978 and 1984; a total of 4318 MI deaths were estimated to be averted by CCUs in 1984 compared with the number of deaths in 1978. Therefore, improvement of MI cases at CCUs may be one of the factors attenuating the rise in death rates in all of Japan.