Clinical impact of follow-up glycosylated hemoglobin on cardiovascular outcomes in diabetic patients with ST-segment elevation myocardial infarction after successful revascularization

Abstract

Background: Diabetes mellitus is known as a strong predictive factor of cardiovascular complication after ST-segment elevation myocardial infarction (STEMI). Recently, glycosylated hemoglobin (HbA1c) reflecting serum glycemic controlled level within 8 to 12 weeks, is studied to investigate relationship with major adverse cardiac events (MACE) after acute myocardial infarction. This study is conducted to evaluate the clinical influence of glycemic control, determined by HbA1c, on MACE in diabetic patients with STEMI after successful percutaneous coronary intervention (PCI). Method: Using data from Korea Working Group on Myocardial Infarction, 303 diabetic patients with STEMI undergoing primary PCI were enrolled. HbA1c was followed up after PCI within total study duration (mean 341.6 days) and patients were divided into three groups based on follow-up HbA1c (FU-HbA1c): optimal, FU-HbA1c <7%; suboptimal, 7%≤FU-HbA1c<9%, poor controlled group, 9%≤FU-HbA1c. We analyzed 12-month cumulative MACE, defined as a composite of mortality, nonfatal myocardial infarction, revascularization or coronary artery bypass graft in each group. Also, we investigated the value of FU-HbA1c to predict MACE using multivariate logistic regression analysis. Results: The incidence rate of 12-month cumulative MACE were significantly different in each group: optimal (7.3%) vs suboptimal (13.0%) vs poor (23.9%) controlled group (p=0.005), which was mainly due to increased non-target vessel revascularization. In multivariate logistic analysis, after adjusting age, sex, body mass index, prior hypertension, Killip stage, peak CKMB, serum creatinine, use of ACE inhibitor, ARB, beta-blocker and statin, each 1% increase in FU-HbA1c was shown to pose 28.4% relative risk of MACE occurrence (OR 1.284, 95% CI 1.023-1.611, p=0.031) in this study. Conclusion: This study suggests that glycemic control, determined by FU-HbA1c, after revascularization in diabetic patients with STEMI was associated with higher incidence rate of 12-month cumulative MACE and FU-HbA1c was shown to be an independent prognostic factor to determine clinical outcomes. These imply continuous tight serum glucose monitoring in STEMI even after successful reperfusion is important and HbA1c might be used as a simple marker, but more research is needed to understand these findings with long-term clinical data.