Introduction: People with diabetes are at increased risk for heart failure (HF), major adverse cardiovascular events (MACE) and death following acute coronary syndromes (ACS). It is important to recognize the most powerful predictors of these events after an ACS as early as possible, in order to address them more aggressively. This is particularly important considering that various studies have shown that this population is undertreated in the setting of ACS.
Objectives: To characterize a diabetic population presenting with ACS and to determine independent predictors of HF, MACE and mortality on follow-up.
Methods: This was a longitudinal, observational, retrospective study including 471 consecutive diabetic patients, both previously known and newly diagnosed, hospitalized for ACS in a single center between May 2004 and December 2006. A mean 12-month follow-up was conducted. Cox regression analysis was used to determine the independent predictors of HF, MACE and mortality on follow-up, divided into different periods--1 month, 6 months and 1 year.
Results: Of the overall diabetic population, 67.3% were male and mean age was 69 +/- 11 years. Mean glomerular filtration rate (GFR) was 62 +/- 22 ml/min and mean left ventricular ejection traction (LVEF) was 50%. diagnosis on admission was ST-elevation myocardial infarction (STEMI) in 31.3%, non-ST elevation myocardial infarction (NSTEMI) in 50.1%, unstable angina (UA) in 14.3% and ACS with left bundle branch block or pacemaker in 4.2%. Cardiac catheterization was performed in 55.6% of the patients during the index hospitalization. Mortality during hospitalization and at 1 year was 6.4% and 10.4%, respectively. The one-year MACE rate was 20.4% and hospitalization for HF occurred in 10.1% of the patients. The independent predictors of HF at 1 year were blood glucose on admission > 184.5 mg/dl, GFR < 63.8 ml/min, LVEF < 46.5% and NSTEMI, while predictors of mortality were LVEF < 40.5% and Killip class on admission > I. Blood glucose on admission > 130.5 mg/dl and LVEF < 49.5% were independent predictors of MACE, whereas cardiac catheterization was a protective factor.
Conclusion: Following ACS diabetic patients have high rates of mortality, HF and MACE. The low rate of invasive strategy may contribute to this situation. HF during hospitalization, whether by low LVEF or Killip class > I, and higher blood glucose on admission were powerful predictors of poorer outcome. Moreover, the use of recommended cardiovascular agents and procedures were protective factors. These findings suggest that diabetic patients should not be excluded from recommended cardiovascular interventions. Efforts should be made to identify these high-risk patients as early as possible in order to manage them carefully and aggressively to improve their poor prognosis.