Additive impact of diabetes mellitus on patients with metabolic syndrome and acute ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention

Abstract

Keywords Diabetes mellitus; Metabolic syndrome; Myocardial infarction

Metabolic syndrome (MetS) and its constituent components have been reported to play a pivotal role in the development of coronary artery disease (CAD) and type 2 diabetes mellitus (DM) [1] and [2]. There have been several studies indicating that MetS itself is associated with a risk of CAD progression or mortality, both in patients with and without preexisting CAD, regardless of the presence of DM [3] and [4]. However, the consequence of DM on clinical outcome in MetS patients who underwent primary percutaneous coronary intervention (PCI) due to acute ST-segment elevation myocardial infarction (STEMI) still remains unclear. We investigated whether DM constitutes a risk factor for poor mid-term clinical outcomes in MetS patients who suffered from acute STEMI and underwent primary PCI.

Between November 2005 and January 2008, eligible 1183 MetS patients who underwent primary PCI due to acute STEMI were analyzed in the Korea Acute Myocardial Infarction Registry (KAMIR) [5]. Diagnosis of MetS was performed by the definition proposed by the American Heart Association/National Heart, Lung, and Blood Institute (AHA/NHLBI). These patients were divided to the two groups according to the existence of DM (diabetic MetS group; n = 552, non-diabetic MetS group; n = 631), and followed up during one year. The methods of unpaired Student's t-test, chi-square test, Kaplan–Meier method and multivariate Cox proportional regression analysis were used (SPSS for Window 17.0). The prevalence of components of MetS in both patient groups are illustrated in Fig. 1. Patients in the diabetic MetS group were older (62.9 ± 11.2 vs. 60.5 ± 13.5 years, p = 0.001) and showed higher proportion of previous history of cerebrovascular accident (9.1% vs. 5.7%, p = 0.027), but smokers were more prevalent in non-diabetic MetS group (51.6% vs. 58.4%, p = 0.020). Diabetic MetS group showed significantly lower LVEF (50.5 ± 11.5 vs. 52.2 ± 11.8%, p = 0.015) and lower creatinine clearance (72.3 ± 33.1 vs. 79.1 ± 54.4 mg/dl, p = 0.011). No significant differences were found in the in-hospital and discharge medical treatment. In angiographic findings, multivessel involvement was more prevalent in the diabetic MetS group than non-diabetic MetS group (64.8% vs. 53.3%, p < 0.001). There are no other differences except that more stents were implanted in diabetic MetS group (1.5 ± 0.8 vs. 1.4 ± 0.7, p = 0.005). During 12 month follow-up period, MetS patients with DM had worse outcomes in all-cause death, death and MI, and composite major adverse cardiac events (MACE) (log rank p = 0.002, 0.001, and < 0.001, respectively). In contrast, revascularization rate did not show more than a trend to be worse in the diabetic MetS group (log rank p = 0.052) (Fig. 2). Multivariate Cox regression analysis showed that DM remained as the independent predictor of 12 months MACE after adjustment of confounding factors (HR = 1.70, 95% confidence interval = 1.090–2.660, p = 0.019) (Table 1).