Temporal Trends in the Incidence and Clinical Features of Acute Myocardial Infarction in a Japanese Rural Area From 2006 to 2014

BACKGROUND: Recent temporal trends in the incidence and clinical features of acute myocardial infarction (MI) in the Japanese population are not well known. METHODS AND RESULTS: This study used comprehensive registration for first-ever MI during the 9-year period from 2006 to 2014 in a rural area of northeastern Japan. The study period was divided into three 3-year terms (T1, 2006-2008; T2, 2009-2011; T3, 2012-2014). During the study period, a total of 814 patients with MI were registered. Although the age-adjusted incidence rate (100,000 person-years) in the middle-aged group (<70 years) was relatively stable, the rate for the elderly group (≥70 years) in T3 was significantly lower than that in T1 in both men (368 vs. 279; P<0.01) and women (204 vs. 108; P<0.01). In the general population of the study area, the rate of prescribed anticholesterol drugs was significantly increased during the study period, especially in the elderly population (P<0.01). From a clinical perspective, although the performance rate of primary percutaneous coronary intervention significantly increased with a shortened duration of hospital stay, the in-hospital mortality rate, especially in the elderly, did not significantly decrease during the study period. CONCLUSIONS: The present study is the first to demonstrate a decreased age-adjusted incidence of MI during the period from 2006 to 2014 in a Japanese rural population, especially in the elderly.