Background
Women are known to have poorer outcome after acute myocardial infarction (AMI) than men. The origin of such differences is still poorly explained such as whether it is due to disparities in baseline risk factors or in management after hospitalization. The aim of this study was to identify sex differences in AMI outcomes in Korean population, and to figure out the factors bringing about the gap.
Methods and Results
A total of 8,218 patients (28.1% women) who were hospitalized for acute myocardial infarction from January 2008 to January 2010 were extracted from the nationwide registry of Korea Working Group of Myocardial Infarction (KorMI). Compared with men, women were 10 years older (70.7±10.3 vs. 60.2±12.3 years) and sicker, which means they were associated with higher morbidities such as hypertension and diabetes. In addition, women showed up after longer pain-to-door time, and with a higher Killip class and more complex coronary artery diseases. With regard to treatment, although early invasive strategy was applied more frequenty to male patients (73.2% vs. 65.5%; p<0.001) with non-ST-elevation AMI, primary PCI was given equally to to both sex groups (89.7% vs. 89.5%; p=0.704) with ST-elevation AMI (STEMI). Other theray data including time to revasculization and in-hospital medications were comparbale in the 2 groups. After a median follow-up of 214 days, women showed higher mortality rate than men does (3.2% vs. 2.0%; P=0.002), which gap was main driven by the patients with STEMI (3.3% vs. 1.9%; p=0.006). After adjustment with age, however, the excessive risk in mortality of the women patients actually diminished (adjusted HR, 0.93; 95% CI, 0.69 to 1.26; p=645). Multivariable adjustment rendered similar results (adjusted HR, 0.94; 95% CI, 0.63 to 1.40; p=0.766).
Conclusions
Among Korean patients with AMI, women showed higher mortality rate than men. However, the difference was shown to be mainly related with higher age of the women patients. We conclude that in modern Korean society where PCI is readily available, the excessive mortality rate of women can be largely explained with older age of women at presentation.
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