Incidence and In-Hospital Mortality of Acute Myocardial Infarction: A Report from a Population-Based Registry in Japan

Aim: To investigate the incidence and in-hospital mortality of acute myocardial infarction (AMI) by conforming to the Universal Definition of Myocardial Infarction (UDMI) in a population-based registry. Methods: The Shiga Stroke and Heart Attack Registry is a multicenter, population-based registry in the Shiga Prefecture, designed to evaluate the incidence and prognosis of acute cerebro-cardiovascular diseases. We registered patients with AMI as defined by the UDMI, who developed AMI from January 2014 to December 2015 in the Shiga Prefecture. The incidence rate of AMI was calculated and standardized for age by a direct method using the 2015 Japanese population. We also evaluated the in-hospital mortality among hospitalized patients with ST-elevation myocardial infarction (STEMI) and non-STEMI (NSTEMI). Results: A total of 1,587 patients were diagnosed with AMI, and the age-adjusted incidence rate was 61.9 per 100,000 person-years. The proportions of patients with STEMI, NSTEMI, and type 3 myocardial infarction were 57%, 30%, and 12%, respectively. The incidence rates of AMI increased with age regardless of sex, which was the highest in those 85 years and older, with 389.7 per 100,000 person-years in men and 221.8 per 100,000 person-years in women. Age-adjusted in-hospital mortality among hospitalized patients with STEMI and NSTEMI was 12.3% and 5.8%, respectively. Conclusions: This population-based registry clarified the age-adjusted incidence rate of AMI under the application of the UDMI, highlighting that in-hospital mortality is still high among patients with STEMI in Japan.