Using a single cut-off for stress hyperglycemia in myocardial infarction decreases its prognostic value particularly in diabetes

Relationship between hyperglycaemia at admission and prognosis in patients with acute myocardial infarction: a retrospective cohort study

BACKGROUND

The optimal threshold of hyperglycaemia at admission for identifying high-risk individuals in patients with acute myocardial infarction (AMI) and its impact on clinical prognosis are still unclear.

METHODS

We retrospectively reviewed 2027 patients with AMI admitted from June 2001 to December 2012 in the 'Medical Information Mart for Intensive Care III' database. The significant cut-off values of admission blood glucose (Glucose_0) for predicting hospital mortality in patients with AMI with and without diabetes were obtained from the receiver operating characteristic (ROC) curve, then patients were assigned to hyperglycaemia and non-hyperglycaemia groups based on corresponding cut-off values. The primary endpoints were the hospital and 1-year mortality.

RESULTS

Among 2027 patients, death occurred in 311 patients (15.3%). According to the ROC curve, the significant cut-off values of Glucose_0 to predict hospital mortality were 224.5 and 139.5 mg/dL in patients with diabetes and without diabetes, respectively. The crude hospital and 1-year mortality of the hyperglycaemia subgroup were higher than the corresponding non-hyperglycaemia group (p< 0.01). After adjustment, regardless of the state of diabetes, hyperglycaemia at admission was related to significantly increased hospital mortality in patients with AMI. For patients with AMI without diabetes, hyperglycaemia at admission was positively correlated with the increase of 1-year mortality (HR, 1.47; 95% CI 1.18 to 1.82; p=0.001). Nevertheless, this trend disappeared in those with diabetes (HR, 1.35; 95% CI 0.93 to 1.95; p=0.113).

CONCLUSION

Hyperglycaemia at admission was an independent predictor for mortality during hospitalisation and at 1-year in patients with AMI, especially in patients without diabetes.

Basic types of the first-day glycemia in acute myocardial infarction: Prognostic, diagnostic, threshold and target glycemia

We described the importance of stress hyperglycemia (SH) in critical illnesses and their evaluation in the emergency department (ED) and coronary care unit (CCU). Hyperglycemia is found in over half of the patients with suspected acute myocardial infarction (AMI). SH can be used for several purposes in AMI. Receiver operating characteristic curves are needed to find optimal cut-offs to divide blood glucose levels associated with good from bad prognosis in AMI. There is a need for a consensus for pragmatic classification of first day glycemia in order to be useful in a busy ED and CCU.

Single prognostic cut-off value for admission glycemia in acute myocardial infarction has been used although high-risk stems from hyperglycemia as well as from hypoglycemia (a narrative review)

All original articles and meta-analysis use the single cut-off value to distinguish high-risk hyperglycemic from other acute myocardial infarction (AMI) patients. The mortality rate is 3.9 times higher in non-diabetic AMI patients with admission glycemia ≥6.1mmol compared to normoglycemic non-diabetic AMI patients. On the other hand, admission hypoglycemia in AMI is an important predictor of mortality. Because both admission hypo- and hyperglycemia correspond to higher in-hospital mortality, this graph is recognized as "J or U shaped curve". The review suggests two cut-off values for admission glycemia for risk assessment in AMI instead of single one because hypoglycemia as well as hyperglycemia represents a high-risk factor.

Proposal of a New Approach to Study and Categorize Stress Hyperglycemia in Acute Myocardial Infarction

BACKGROUND

Stress hyperglycemia (SH) is a valid prognosticator of in-hospital complications and mortality in the intensive care unit, and is universally available, simple, and cost-effective. Even small refinements of SH can improve the risk stratification of patients with one of the most important diseases today-acute myocardial infarction (AMI).

OBJECTIVE

The aim of the review was to analyze whether SH nomenclature and methodology have been consistent in the medical literature in order to identify possible methodological faults and to suggest possible solutions.

DISCUSSION

SH nomenclature and glycemic targets have been relatively uniform in recent years, but there has been a pronounced variability in the methodology. Recent meta-analysis showed that AMI patients with new hyperglycemia had a 3.6-fold increased risk of mortality during hospitalization in comparison to those who were normoglycemic. Four SH methodological mistakes were identified. First, using one cutoff value for SH instead of two different values (one for patients with diabetes mellitus [DM] and one for patients without DM). Second, analyzing, for example, either tertiles or quintiles without dividing AMI patients into subgroups according to their DM status. Third, studying only two subgroups (with SH and without SH), without determining the presence of DM, when DM is not analyzed. Fourth, failure to measure glycated hemoglobin.

CONCLUSIONS

The same admission blood glucose (BG) is a marker of different mortality risks in diabetic compared to nondiabetic AMI patients. For example, when admission BG is 108-126 mg/dL (6-7 mmol/L), then the risk of in-hospital mortality is higher in DM patients; however, with an admission BG of 162-180 mg/dL (9-10 mmol/L), the risk is lower in diabetic patients. We can improve the clinical utility of the admission BG in AMI if we analyze four groups of patients (those with and without previously diagnosed DM, and above and below the admission glycemia cutoff values for in-hospital mortality). Those cutoffs should be calculated separately for diabetic and nondiabetic AMI patients.

Association of Admission Glycaemia With High Grade Atrioventricular Block in ST-Segment Elevation Myocardial Infarction Undergoing Reperfusion Therapy: An Observational Study

Several studies have demonstrated the association between elevated admission glycaemia (AG) and the occurrence of some arrhythmias such as atrial fibrillation, ventricular tachycardia, and ventricular fibrillation after myocardial infarction. However, the impact of elevated AG on the high grade atrioventricular block (AVB) occurrence after ST-segment elevation myocardial infarction (STEMI) remains unclear. Included were 3359 consecutive patients with STEMI who received reperfusion therapy. The primary endpoint was the development of high grade AVB during hospital course. Patients were divided into non-diabetes mellitus (DM), newly diagnosed DM, and previously known DM according to the hemoglobin A1c level. The optimal AG value was determined by receiver operating characteristic curves analysis with AG predicting the high grade AVB occurrence. The best cut-off value of AG for predicting the high grade AVB occurrence was 10.05 mmol/L by ROC curve analysis. The prevalence of AG ≥ 10.05 mmol/L in non-DM, newly diagnosed DM, and previously known DM was 15.7%, 34.1%, and 68.5%, respectively. The incidence of high grade AVB was significantly higher in patients with AG ≥ 10.05  mmol/L than <10.05  mmol/L in non-DM (5.7% vs. 2.1%, P < 0.001) and in newly diagnosed DM (10.2% vs.1.4%, P < 0.001), but was comparable in previously known DM (3.6% vs. 0.0%, P = 0.062). After multivariate adjustment, AG ≥ 10.05  mmol/L was independently associated with increased risk of high grade AVB occurrence in non-DM (HR = 1.826, 95% CI 1.073-3.107, P = 0.027) and in newly diagnosed DM (HR = 5.252, 95% CI 1.890-14.597, P = 0.001). Moreover, both AG ≥ 10.05  mmol/L and high grade AVB were independent risk factors of 30-day all cause-mortality (HR = 1.362, 95% CI 1.006-1.844, P = 0.046 and HR = 2.122, 95% CI 1.154-3.903, P = 0.015, respectively). Our study suggested that elevated AG level (≥10.05  mmol/L) might be an indicator of increased risk of high grade AVB occurrence in patients with STEMI.