Acute hyperglycaemia and inflammation in patients with ST segment elevation myocardial infarction

Abstract

Acute hyperglycaemia in patients with acute coronary syndromes (ACS) is associated with increased cardiovascular (CV) risk among both diabetic and non-diabetic patients although the mechanisms underlying this association are not clearly understood. Acute hyperglycaemia in patients with ACS may be associated with increased systemic inflammation. Leukocytes are the major cellular mediators of inflammation and their elevated count is associated with higher CV event rate in ACS patients. Thus, it is possible that there is a relationship between acute hyperglycaemia and high leukocyte count and concomitant presence of these two conditions may contribute to increased CV risk among patients with ST segment elevation myocardial infarction (STEMI). To investigate the relationship between acute hyperglycaemia and high leukocyte count and to evaluate its association with outcomes in patients with STEMI. Glucose level and leukocyte count on admission were measured in 246 patients with STEMI admitted in 2004- -2007 to the First Department of Cardiology and Hypertension at the University Hospital in Cracow who were treated with an early invasive management strategy. Patients were divided into two groups, with acute hyperglycaemia (glycaemia on admission ≥ 7.8 mmol/L) and with normoglycaemia (glycaemia on admission < 7.8 mmol/L). Leukocyte count was defined as high when it was greater than or equal to the median in the overall study group. Acute hyperglycaemia was noted in 136 (55.3%) patients. Median leukocyte count on admission in the overall study group was 10.8 × 103/mm3 (interquartile range: 8.5-13.0). Significantly higher in-hospital mortality (11.8% vs. 1.8%, p = 0.0029) and higher rates of cardiogenic shock (10.3% vs. 0.9%, p = 0.0022), Killip class > 1 heart failure (HF; 44.1% vs. 20.0%, p < 0.0001), atrial fibrillation (11.0% vs. 3.6%, p = 0.0308), ventricular fibrillation (5.9% vs. 0.9%, p = 0.0389), repeated percutaneous coronary angioplasty (5.2% vs. 0.0%, p = 0.0158), the primary endpoint defined as death and/or cardiogenic shock (16.9% vs. 1.8%, p = 0.0001), and the secondary endpoint defined as atrial fibrillation and/or second or third degree atrioventricular block and/or HF and/or stroke/transient ischaemic attack (53.7% vs. 23.6%, p < 0.0001) were noted in the acute hyperglycaemia group in comparison with the normoglycaemic group. Adverse events were associated with high leukocyte count in all patients and in both diabetic and non-diabetic subgroups. Mean leukocyte count was higher in patients who died (13.3 ± 4.01 vs. 11.0 ± 3.56 [103/mm3], p = 0.0115; 14.2 ± 1.59 vs. 10.8 ± 3.18 [103/mm3], p = 0.0210; and 13.5 ± 4.79 vs. 11.1 ± 3.72 [103/mm3], p = 0.0363 in the overall study group, diabetics and non-- diabetics, respectively), in patients with cardiogenic shock (14.0 ± 4.56 vs. 11.0 ± 3.52 [103/mm3], p = 0.0019; and 15.4 ± 4.93 vs. 11.0 ± 3.66 [103/mm3], p = 0.0007 in the overall study group and non-diabetics, respectively), and in patients with HF (12.1 ± 3.78 vs. 10.8 ± 3.51 [103/mm3], p = 0.0083; and 12.1 ± 3.39 vs. 10.3 ± 2.90 [103/mm3], p = 0.0159 in the overall study group and diabetics, respectively) as compared to patients without respective adverse events. Glucose level on admission correlated positively with the on-admission leukocyte count. This correlation was statistically significant in the overall study group (r = 0.25, p < 0.0001), in diabetics (r = 0.27, p = 0.021), and in non-diabetics (r = 0.35, p < 0.0001). Patients with both acute hyperglycaemia and the leukocyte count greater than or equal to the median in the overall study group had a higher in-hospital risk of death and/or cardiogenic shock (odds ratio 17.6, 95% CI 1.9-165.3, p = 0.0122). Acute hyperglycaemia is associated with worse in-hospital outcomes in patients with STEMI. More severe inflammation (defined as leukocyte count on admission) is noted in STEMI patients with adverse events. A significant positive correlation can be seen between glucose level and leukocyte count on admission, and concomitant presence of both acute hyperglycaemia and more severe inflammation in patients with STEMI was found to be an independent predictor of poor in-hospital outcomes.