Onset, Time to Recurrence, and Recurrence Risk Factors of Myocardial Infarction and Ischemic Stroke: 10-Year Nationwide one-Million Population Database

Background and Purpose We aimed to determine the differences in the pathophysiology of myocardial infarction (MI) and ischemic stroke (IS) and present their basic epidemiologic data for public health policy. Methods We included patients with a history of admission with diagnostic codes of MI and IS in the National Health Information Database (NHID) of the National Health Insurance Service (NHIS) Sample Cohort 2002-2013. We investigated the time to primary and secondary events, difference in incidence based on sex, time interval for the secondary event following the primary event in MI and IS, and the relative risk of recurrent events compared with that of primary events. Results The mean age of onset of IS was significantly higher than that of MI (65.67±12.25 vs. 60.4±13.07 years; P <0.05). The mean period from primary IS to secondary IS was significantly shorter than that from primary IS to secondary MI (2.09±2.80 vs. 5.35±2.90 years; P =0.016). The mean period from primary MI to secondary MI was significantly shorter than that from primary MI to secondary IS (2.30±2.75 vs. 5.16±3.26 years; P <0.001). The incidence of IS in men was significantly higher than that in women. The relative risk of recurrent IS and MI was greater than that of the primary event. In patients younger than 70 years, the incidence of MI was higher than that of IS, while in those above 70 years it was lower ( P <0.05). Conclusions The age at onset, time to recurrence, sex, and relative risks are significantly different between ischemic stroke and myocardial infarction, suggesting that the underlying pathophysiologic mechanisms might be different between the two.