Fasting Glycaemia Is A Predictor . Of Outcome After Acute Myocardial Infarction

Background: Patients with recent myocardial infarction have an increased incidence of impaired fasting glucose (IFG) and new-onset diabetes. There is a clear relationship between elevated fasting glucose during acute myocardial infarction and increased mortality and morbidity risk. Objective: To find out the impact of fasting glycaemia as a predictor of outcome of patients with acute myocardial infarction. Methods: A total of 102 patients with acute myocardial infarction of first attack were selected according to inclusion and exclusion criteria. Fifty-one patients with acute myocardial infarc­tion having fasting hyperglycaemia were enrolled as case group and another 51 patients with acute myocardial infarctions having fasting euglycaemia were enrolled as control group. Results: Among the diabetic patients, acute left ventricular failure (ALVF) developed in 22 (68.8% ), arrhythmias in 5 (16.6%) and cardiovascular mortality in 8 (25.0% ) patients ; it was 7 (36.8%), 4 (21.1 %) and 4 (21.1 %) respectively in IFG patients; and 7 (13.7%) ,4 (7.8%) and 2 (3.9%) respec­tively in euglycaemia patients. Acute left ventricular failme and 30 days CV mortality significantly differed among the groups (p<0.001 and p=0.015 respectively). But no significant difference in arrhythmias (p=-0.284). Conclusions: The patients of impaired fasting glucose (IFG) and diabetes mellitus both were predictor for in hospital heart failure (ALVF) and 30-day cardiovascular mortality as compared to euglycaemia.


Introduction :
Diabetes is an established risk factor for cardiovascular disease, and the risk of cardiovascular disease increases with worsening hyperglycaemia .r'2Furthernore, coronary artery disease is the most common cause of death in patients with diabetes.3 Patients with coronary artery disease and a recent myocardial infarction or acute coronary syndrome (ACS) have an increased incidence of impaired fasting glucose (IFG) and new-onset diabetes .o-6Although the mechanisms underlying this association are not fully understood.In patients who have had recent myocardial infarction, the lack of insulin associated with hyperglycaemia may lead to a decrease of glycolytic substrate for cardiac muscle and excessive free fatty acids .7 These changes may reduce myocardial contractility at Address for Correspondence: Dr.Mohammad Shofiullah.

Head of Department of Cardiology. Sylhet MAG Osmani Medical College Hospital
Sylhet.Email: shofiullahmoh ammad@yahoo.com.sg.Mobile no.0171I 10171 I IBSMMU J 20] s ; 6 (2) : t 35-1401 increased oxygen cost, lead to pump failure, and promote arrhyhmias Several studies have also documented a clear relationship between elevated fasting glucose during acute myocardial infarction and increased mortality risk .e-12UnHke the random glucose level on admission, IFG may be a better reflection of abnormalities in underlying glucose metabolism, and thus may be a better predictor of both short-tefin and long-term outcomes.In one of the earlier studies on this issue, Suleim an et al.e demonstrated that while both admission and fasting glucose levels predicted 30-day mortality in non-diabetic patients with acute myocardial infarction, fasting glucose was the better discriminator.There was no study in Bang- ladesh regarding the relationship between fasting plasma glucose level and complications after acute myocardial infarction including mortality So, this study was designed to find out the impact of fasting glycaemia as a predictor of outcome of patients with acute myocardial infarction in Bangladeshi patients at Sylhet.

Methods :
This was a prospective comparative study done in the Department of Cardiology, Sylhet MAG.Osmani Medical College Hospital, Sylhet from lst July 2008 to 30th June 2010.A11 patients having acute myocardial infarction were considered as study population.Fifty-one acute myocardial infarction patients having fasting hypergly- caemia (diabetes mellitus and IFG) were enrolled as study group and 51 acute myocardial infarction patients having fasting euglyc aemia were enrolled as control group.
Before enrollment in this sfudy informed written consent was obtained from the patients after full explanation of the putpose of the study .They were informed of their right to withdraw from the study at any stage.

Procedure of Data Collection:
A detailed history and thorough physical examination was done in each patient on admission.Criteria for myocardial infarction was arly two of the following: cardiac chest pain lasting at least 30 minutes; 1 mm ST elevation in at least one standard lead or 2 mm ST elevation in two or more contiguous chest leads; or Serum troponin I (higher than the upper limit of reference range) .tt'14Dahon demo- graphics, cardiovascular risk factors, and medical history were collected along with baseline clinical data and admission data like systolic blood pressure (SBP)   ,diastolic blood pressure (DBP) and heart rate.Echocardiography was performed at day 3 to calculate left ventricular ejection fraction (LVEF).Data on acute reperfusion procedures-thrombolysis and primary coronary interven- tion (PCI) was collected.The outcomes were defined as in-hospital heart failure, ventricular arrhythmia (ventricular tachycardia or ventricular fibrillation).
In-hospital heart failure was defined as rales over more than half of the lung field (Killip class II), pulmonary oedema (Killip class III), or cardiogenic shock (Killip class IV)." Friedwald's formula, LDL -(T.Chol -HDL-C) -TG/5 when the values of TG were less than 400 mgo/o.|SRelevant findings were recorded by using a pretested 136 structured data collection sheet designed for the study.
The patients were followed up up to 30 days in the cardiology department.Communi- cation with the patient's attendants was maintained over mobile phone as recorded in the research instrument.
Data were processed and analyzed with the help of computer program SPSS 16.0 version for windows.All continuous datatested were expressed as mean and stand- ard deviation.Comparisons of continuous variables between the groups of patients were performed by 'Z' test.
Qualitative data were expressed as frequency and percent- ages; and comparison was done by the Chi-Square (X2) test or Fisher's Exact test.Logistic regression analysis was done to find out relationship between different levels of glycaemia & outcome. (P) value of less than 5% (p<0.05) was considered statistically signific atft.
A11 information was collected confidentially with complete respect to the patient's wish and without arly force or pressure.Patient's rights were preserved accord- ing to Helsinki declaration.o.se8 tt 0.425 tt There were 80.4% male and 19.6% female in the hyperglycaemic group; while 90.2% male and 9.8% female in euglycaemic group.

Table-II
Distribution of patients according to history of hypertension (n:102) Age Group among the groups (p<0.001) and p-0.015 respectively).

Discussion :
In this study the me an age of patients in hyperglycaemic group was 52.51 10.97 years; whereas the mean age of the euglycaemic group was 49.82 10.96 years.The mean age of the patients in both groups was almost identical (p>0.05) which is similar to the findings of Vural et a1.r6 where the me afi age of myo cardial infarction patients was 54 8 years.In the current study, there were 80.4% male and 19.6% female in the hyperglycaemic group; 90.2% male and 9.8% female in euglycaemic group.The sex difference between the groups was not statistically significarrt (p:0.598).This result was concordance with the study of Barukat et al.t7 that 87.0% of Bangladeshi patients with acute myocardial infarction and 70.0% of white patients were male.Aronson et a1.10 found 73% male and 23% female in the hyperglycaemic group ;84% male and 16% female in euglycaemic group of patients with acute myocardial infarction.In this study 80.4% of patients were smoker and L9.6% were non-smoker in hyperglycaemic group; whereas in euglycaemic group 86.3% of patients were smoker and 13.7% patients were non-smoker.The difference between the two groups was statistically not significant (p-0.425).This result was supported by Barakat et al. 17 that 71.3% of Bangladeshi immigrants patients and 70.3% of white patients with acute myocardial infarction were smoker.Vivas et a1.18 found 84.8% of their acute coronary syndrome was smoker.In the current study 3 9.2% patients had history of hypertension, 27 .5o/opatients had no history of hypertension and 33.3% unknown about their blood pressure in hyperglycaemic group; while in euglycaemic group, 45.Lo/o patients had history of hypertension2l,.6%patients had no history of hypertension and 33.3% unknown about their blood pressure.The difference between the two groups was statistically not significant (p:0.752).This result was similar to the study of Barakat  This result was also supported by Suleiman et al.9 that diabetes mellitus (DM) [OR-2.6;95% of CI:1.3-5.0;p-0.004) were independent predictor of 30-days cardio- vascular death and heart failure as compared to normal glucose level.Nau et al.te found FG as independent predictors of in hospital major adverse cardrac events (death, reinfarction and heart failure) of acute MI patients (OR-1 .03; 95% of CI-3 .46-46.92; p-0.001) as compared to that of admission glycaemia.

Conclusion :
The patients of hyperglycaemic group had 8.3 times more likely to develop acute left ventricular failure and 7.5 times more likely to had 30 days cardiovascular mortality as compared to that of euglycaemic group.
The patients of impaired fasting glycaemia and diabetes mellitus both were predictor for in hospital heart failure as compared to euglycaemia.The measurement of a fasting blood glucose level provides additional information in identify high-risk group of post-infarction patients.
with acute myocardial infarction in Bangladeshi patients at Sylhet.

Figure in the parenthesis
Figure in the parenthesis indicates corresponding percent- age.

Table - I
Base line characteristics of the patients (n-102)

Table - IV
Fasting glycaemia as a predictor for in-hosprtal heart Binary logistic regression analysis was applied to analyze the data. *

Table -
IV:showed the fasting glycaemia as a predictor for in-hospital heart failure.The patients of impaired fasting glucose (IFG) was a predictor for in-hospital heart failure as compared to euglycaemia (OR-3 .667;95% of CI:\.075-4L.257;p-0.038).Diabetes mellitus was also a predictor for in-hospital heart failure as compared to status schi-Square (X2) Test was applied to analyze the data.

Table - III
et al.r1 that 43.5% of Bangladeshi patients and 38.4% of white patients with acute myocardial infarction had history of hypertension.138 In hyperglycaemic group 56.9% of patients developed acute left ventricular failure; while in euglycaemic group, 13.7% of patients developed acute left ventricular failure during hospital stay.The patients of hyperglycaemic group compared to that of euglycaemic group was 8.3 times more likely to developed acute left ventricular failure during hospital stay (OR-S .286;95% of CI:3 .137-21.883; p<0.001).This result was almost similar to the study of Verges et a1.11 that 45.0% of hyper- glycaemic patients developed acute left ventricular failure during hospital stay; while in 13.7% of eugLycae- mic patients developed acute left ventricular failure during hospital stay.In hyperglycaemic group, 17.6% patients developed arrhythmias; while in euglycaemic group, 7 .8%patients developed arrhythmias during hospital stay.The development of arrhythmias during hospital stay in both groups were almost similar (oR--2.518;95% of CI-}.722-8.781;p-0.138).This result was consistent with the study of Verges et al.Lt that 10.8% of hyperglycaemic patients developed arrhythmias during hospital stay; while in 10.0% of euglycaemic patients developed arrhythmias during hospital stay.In hyperglycaemic group 23.5% patients, while in eugly- caemic group 3.9% patients.had 30 days cardiovascular mortality as compared to that of euglycaemic group.This result was supported by Nua et al.le that 16.0% patients had cardiovascular mortality in hyperglycaemic group; while no cardiovascular mortality in glycaemic group.