Clinical characteristics and outcomes in acute myocardial infarction patients with versus without any cardiovascular risk factors

BACKGROUND/AIMS: Although cardiovascular (CV) risk factors are well established, some patients experience acute myocardial infarction (AMI) even without any risk factors. METHODS: We analyzed total 11,390 patients (63.6 ± 12.6 years old, 8,401 males) with AMI enrolled in Korea Acute Myocardial Infarction Registry-National Institute of Health from November, 2011 to December, 2015. Patients were divided into two groups according to the presence of any CV risk factors (group I, without risk factors, n = 1,420 [12.5%]; group II, with risk factors, n = 9,970 [87.5%]). In-hospital outcomes were defined as in-hospital mortality and complications. One-year clinical outcomes were defined as the composite of major adverse cardiac events (MACE). RESULTS: Group I was older (67.3 ± 11.6 years old vs. 63.0 ± 12.7 years old, p < 0.001) and had higher prevalence of female gender (36.2% vs. 24.8%, p < 0.001) than the group II. Group I experienced less previous history of angina pectoris (7.0% vs. 9.4%, p = 0.003) and the previous history of cerebrovascular accidents (3.4% vs. 6.9%, p < 0.001). In-hospital mortality (2.6% vs. 3.0%, p = 0.450) and complications (20.6% vs. 20.0%, p = 0.647) were no differences between the groups. And 1 year clinical outcomes (5.7% vs. 5.1%, p = 0.337) were no differences between the groups. In multivariate logistic regression analysis, serum creatinine level (hazard ratio, 1.35; 95% confidence interval, 1.05 to 1.75; p = 0.021) were independent predictors of 1 year MACE in patients without any CV risk factors. CONCLUSIONS: Elderly female patients were prone to develop AMI even without any modifiable CV risk factors. We suggest that more intensive care is needed in AMI patients without any CV risk factors who have high serum creatinine levels.