The Role of HbA1c in Severity and Mortality Rate of ST Segment Elevation Myocardial Infarction for Hospitalized Libyan Non-Diabetic Patients
Asgad Abdalgbar1,2 and Hanan KG Altalhi¹*
1Faculty of Medicine, University of Omar El Mukhtar, Libya
2Faculty of Medical Technology, University of Omar El Mukhtar, Libya
Submission: November 05, 2019; Published: December 03, 2019
*Corresponding author: Hanan KG Altalhi, Faculty of Medical Technology, University of Omar El Mukhtar, Albayda, Libya
How to cite this article: Asgad Abdalgbar, Hanan KG Altalhi. The Role of HbA1c in Severity and Mortality Rate of ST Segment Elevation Myocardial Infarction for Hospitalized Libyan Non-Diabetic Patients. Curre Res Diabetes & Obes J. 2019; 12(3): 555840. DOI:10.19080/CRDOJ.2019.12.555840
Background: The severity of coronary artery disease (CAD) is directly related to the quality of glucose control in diabetic patient. Additionally, diabetes is associated with increased mortality following acute myocardial infarction compared to general population.
Objectives: To evaluate the association of HbA1c level and severity of CAD, and outcome of non-diabetic patient with STEMI in our hospital.
Patients and Methods: 60 consecutives non-diabetic patient with acute ST elevation myocardial infarction were treated with thrombolytic therapy included in the present prospective study. Blood glucose and HbA1c level of all patients were measured within 3 hours of admission. Patient were divided in to 3 groups according to HbA1c level: with cut-off 6.5% as diagnostic criteria of diabetes mellitus according to (American diabetes association) group (1) 6.5%, group (2) 6.5 to 8.5%, group (3) 8.5% and above. In hospital. mortality and morbidities of acute STEMI were compared between groups.
Results: The mean age was 63±15 year and mean body mass index was 26. 6±6 kg/m², 24 patients (40%) had history of hypertension, 27 patients (45%) of dyslipidemia, 36 patients (60%) were smoker. We found 45 patients with HbA1c ≤ 6 5%, 5 patients with HbA1c 6.5 -8.5 %, 10 patients with HbA1c ≥ 8.5%. There was strong correlation between admission of HbA1c and admission glucose level (P< 0.001). Infarct size as measured by peak creatinin kinase, was not correlated with HbA1c level.
Conclusions: HbA1c is an important risk marker in the absence of history of diabetes mellitus in patients with AMI. The optimal management in these patients may contribute in decrease hospital mortality.
Patients with diabetes are at 3-4 times increased risk for cardiovascular mortality compared with non-diabetes . In acute coronary syndrome, glucose metabolism is modified and stress hyperglycemia commonly occur secondary to increase catecholamine level . In addition to the higher rate of acute ST- elevation myocardial infarction (STEMI) in diabetes, hyperglycemia is associated with poor prognosis in these patients [3-5].
Higher HbA1c level was associated with high cardiovascular disease and death . There were some other studies supporting the association between admission serum HbA1c level and increased long-term mortality of non-diabetic patients admitted with STEMI and higher rate CAD in these patients [7,8]. We have evaluated the association of admission level of HbA1c with the hospital outcome of non-diabetic patient with STEMI.
All patients of both sexes sustaining acute ST elevation myocardial infarction without diabetes were including in the study. Patients with sepsis, hemoglobinopathies or hypothyroidism, tumor, connective tissue diseases, those with sub-acute or chronic MI (longer than 48 hr between first symptom and admission) those with renal failure, hepatic failure iron deficiency anemia and those with past history of diabetes
or used anti diabetic medication were excluded from the study.
Acute myocardial infarction was defined according to the
(European Society of Cardiology and American College of
Cardiology Criteria). Increased creatine kinase predominantly
in the myocardial band fraction and or increased troponin I
(creatine kinase 400 U /L or higher and or cardiac troponin I
2μg / L or higher), ischemic symptoms (mainly constrictive
chest pain, lasting longer than 30 min), and or abnormal
electrocardiography (ST elevation 1 mm or greater on at least
two derivation). MI was defined as acute if the time elapsed
between the first symptom and admission was 48 hr or less.
Only patients who underwent thrombolytic treatment were
included in the study.
All patients were in cardiac care unit, a brief history was
obtained from each patient presenting with acute chest pain
including presence of risk factors like smoking and hypertension,
dyslipidemia and previous history of ischemic heart disease.
Clinical examination was done emphasis on signs of cardiac
failure, 12 leads electrocardiography (ECG) was done at cardiac
care unit and blood sample were sent to laboratory, blood
glucose and HbA1c level of all patients were measured within
3 hr of admission regardless of whether they had been fasting
or not and for cardiac enzyme. The fasting lipid profile was
determined on the morning following admission and included
total cholesterol, high density lipoprotein and triglyceride.
All patients were considered for thrombolytic therapy
(Injection streptokinase 1.5 million units over one hour) in the
absence of all contraindication the management was according to
standard treatment protocol. All patients underwent continues
ECG monitoring for at least 48 hours on admission to cardiac
care unit and daily during hospital stay.
Patients were divided into three groups according to the
level of HbA1c with cut-off 6.5% as diagnostic criteria of diabetes
mellitus according to (American Diabetes Association 2010) for
diagnosis and classification of diabetes mellitus. Patient with
HbA1c level of 4.5% to 6.4 % group (1), patients with HbA1c
level 6.5% to 8.5% group (2) and patients with HbA1c level
higher than 8.5 % group 3).
None of these patients received glucose, Insulin or potassium
infusion therapy during admission. All subjects were hospitalized
one week after acute myocardial infarction and hospital records
were reviewed at this time.
Selective coronary angiography was performed after 1
month. Coronary angiogram were analyzed by two experienced
observers who were blinded to the identities and clinical
information of the patients .Vessel scores were ranged from zero
to three, according to the number of diseased major pericardial
vessel with significant stenosis (greater than 50% stenosis of the
Table 1: Total 60 patients with STEMT were studied. Patients
were divided on the bases of admission HbA1c group (1) ≤ 6.5 %;
group (2) 6.5-8.5 %; group 3 ≥ 8.5%. The clinical and biological
characteristic according to HbA1c are summarized in Table 1.
The mean age was 63±15 year and mean body mass index was
26. 6±6 kg/m², 24 (40%) had history of hypertension, 27 (45%)
of dyslipidemia, 36 (60%) were smoker. We found 45 with
HbA1c ≤ 6 .5%; 5 with HbA1c 6.5-8.5%, 10 with HbA1c ≥ 8.5%.
Data are mean±SD, BMI: Body Mass Index ie body weight (kg)
/ hight²(m²). SBP/ DBP: Systolic / Diastolic Blood Pressure; CK:
There was strong correlation between admission HbA1c and
admission glucose level (P< 0.0001). Infarct size as measured by
peak creatinine kinase, was not correlated with HbA1c level.
Table 2: Patients were divided according to admission
glucose [group (1), 6.9 mmol/L; group (2), 7 to 8.1 mmol/L;
group (3), 8.2 to 9.5 mmol/L; group (4) ≥ 9.6 mmol/ L]. There
was significant positive correlation between admission glucose
and infarct size measured by peak creatinine kinase level
IQR: Interquartile Range; CK: creatinine kinase. Value are expressed as median (IQR).
Table 3: At the end of fourth week coronary angiography
performed in remaining 54 patients, revealed that there was
significant correlation between HbA1c level at admission and
number of disease vessel(P=0.001).
Table 4: We found that patients who died by day 5 were
significantly different from patients with non-lethal acute
myocardial infarction, with regard to admission plasma glucose
(16.6±5.4 vs 8.3±3.4 mmol/L , P=0.0001), age (74±10 vs 62±13
HbA1c: Glycosylated Hemoglobin
There was no significant difference in HbA1c value in the
survivor and non-survivor (6.7±1.8 vs 6±0.2, P=0.15).
The present study confirms previous observation in diabetic
subjects suggesting that higher glucose level during AMI are
associated with increased mortality . In recent study, Timmer
J et al,  reported that higher admission glucose level in
non-diabetic patients treated with reperfusion therapy for ST
segment elevation MI were associated with significantly larger
enzymatic infarction size and lower left ventricular ejection
fraction. This is because a stress response is accompanied by high
level of catecholamine and cortisol and these hormones increase
glucogenolysis and lipolysis and reduce insulin sensitivity,
resulting in elevated glucose level . There for, patients with
elevated glucose level may represent with an increased stress
response, due to more sever hemodynamic compromise or more
extensive myocardial damage [11,12].
Elevated cytokine, particularly tumor necrosis factor-Alpha
(TNF-α), also increase glucose level. TNF-α is released in AMI and
directly decrease myocardial contractility, probably by inducing
myocardial apoptosis [5,13]. TNF –α also cause impaired
endothelial function . This in turn, may be responsible for the
impaired myocardial perfusion. We found positive correlation
between peak creatinin kinase and admission plasma glucose
concentration in our patients. Conversely, no correlation was
found with HbA1c value. Although acute hyperglycemia at
admission and during stay has clearly been associated with
adverse outcome in patients with acute MI [7,15,16].
Our study shows admission HbA1c level are not associated
with high mortality in non-diabetic STEMI population treated
with streptokinase. In our study high HbA1c in non-diabetic
patients associated with multi vessels involvement of coronary
arteries. Similarly, Cak Mak et al,  reported a significant
correlation between HbA1c level at admission and positive
exercise that result after the four weeks follow up.
Hyperglycemia in STEMI patients was strongly associated
with increased mortality within 5 days although there is clear correlation between admission glucose and HbA1c level, they
appear to represent related but different phenomena. Patients
with elevated glucose level have larger MI area.
Recently a prospective cohort study showed that in nondiabetic
general population, as elevated HbA1c level is a
risk factor for the development of cardiovascular events
independently of fasting glucose . The international expert
committee recommended the use of HbA1c in diagnosis diabetes
with a cut-off 6.5 % .
The advantage of HbA1c over the fast blood glucose are its
lower intra-individual variability, assessment in non-fasting
state and superior in monitoring blood glucose level [6,19]. Preis
& Selvin et al, [1,6] has suggested that glycosylated hemoglobin
is superior to fasting blood glucose in predicting long-term
risk of CAD in non-diabetes. Similar result is reported by Park
and colleagues among non-diabetic women . In a cohort of
European men, khaw and colleagues  reported that HbA1c
correlates linearly to subsequent cardiovascular morbidity .
The American Diabetes Association suggests that individual with
HbA1c concentration of 5.7- 6.4% should be informed of their
increased risk for diabetes as well as cardiovascular disease [19,
HbA1c is an important risk marker in the absence of history of
diabetes mellitus in patients with AMI. The optimal management
in these patients may contribute in decrease hospital mortality.
People at high risk for type II diabetes mellitus should receive
lifestyle counseling and if needed pharmacological therapy
to reduce their risk of developing hyperglycemia and type
II diabetes mellitus but specially to prevent or slow the
development of CAD.