DIABETIC JEOPARDIZE OF ACUTE MYOCARDIAL INFARCTION CHEST PAIN

Objective: Diabetic neuropathy may mask the typical ischemic chest pain and diabetics may carry longer presentation times in cases of acute STEMI. Diabetics may complain of chest pain less frequently, while atypical clinical presentations of STEMI could be more common compared to non-diabetics. Aim of this study was to assess the potential impact of diabetes on STEMI related chest pain, its severity, characteristics and nonspecific clinical features.


INTRODUCTION
ST-segment Elevation Myocardial infarction (STEMI) is among the leading causes of morbidity and mortality worldwide with more than nine million people suffering from ischemic heart disease (IHD). 1,2 Diabetes mellitus (DM) is one of the major modifiable risk factors for IHD and is also considered as an equivalent to coronary artery disease (CAD). 3 In addition to its major role in the development of atherosclerosis and CAD, it may frequently cause peripheral and autonomic neuropathy, vasculopathy and diabetic cardiomyopathy. 4 Diabetes has been linked to a higher risk for CAD and almost twice short-and long-term mortality after STEMI compared to non-diabetics. 5 Around 20% diabetics have an abnormal cardiovascular autonomic function. 6 This could lead to the atypical presentations of myocardial ischemia and acute STEMI. 7 Associated peripheral neuropathy may mask the typical ischemic chest pain and diabetics have been shown to carry longer presentation times compared to non-diabetics in cases of acute STEMI. 5 Diabetics may complain of chest pain less frequently, while atypical clinical presentations of STEMI could be more common compared to nondiabetics. 8,9 In cases of acute STEMI, myocardial salvage and mortality reduction depends largely on earliest reperfusion strategies. 10 About 18 to 40% patients present later than 12 hours of STEMI onset in European and North American well-developed systems of care. 11,12 Even more patients present late in the healthcare systems of developing countries. 13 In addition to the circumstantial, logistic, social and educational factors contributing to such delays, diabetes may contribute by masking the typical chest pain or discomfort so that a substantial proportion of persons suffering from acute STEMI may not attribute their symptoms to it at an early stage. The study was conducted to assess the potential impact of diabetes on STEMI related chest pain, its severity, characteristics and non-specific clinical features. Findings of the study could provide insight on how diabetes can mislead diabetic STEMI patients in recognizing their initial symptoms as well as pose difficulties to the first contact healthcare workers in diagnosing STEMI in its earliest phase while the electrocardiographic and biomarker evidences are still awaited. Important inferences drawn from the study could be incorporated into general population-based educational and social awareness programs in addition to further enlightening the first contact healthcare providers to consider the potential impact of diabetes while assessing possible STEMI patients.

METHODOLOGY
The descriptive, cross-sectional study was conducted in patients admitted in Emergency department of Cardiology unit of Chaudhary Pervaiz Elahi Institute of Cardiology, Multan for a period of six months. Total of 254 consecutive patients with first episode of STEMI were included in the study after approval from Ethical and Research Review Committee of the institute and informed consent from the patients.
Demographic parameters and CAD risk factor profiles were recorded. Questions were asked about the chest pain and its severity was graded via verbal rating scale of pain with score 1-4 as mild pain, 5-7 as moderate pain, 8-10 as severe pain. Specific characters of chest pain (pressure over precordium, strangulating pain, squeezing pain and burning over precordium) were also inquired. Patients were also asked about the radiation of chest pain or discomfort to left arm, both arms, neck, lower jaw, interscapular region, or epigastrium. Patients were then assessed for occurrence of associated clinical features to chest discomfort including episodes of vomiting, profuse sweating (all over the body, drenching clothes and irritating for the patient), syncope, shortness of breath, fits, and indigestion symptoms. Patients were labelled as diabetics if already on hypoglycemic drugs, HbA1C > 7.0 % or fasting blood glucose > 120 mg/dL. All data was analyzed by computer software SPSS version 20. Demographics and STEMI types were assessed and stratified among diabetic and nondiabetic groups. Chest pain severities, characters, radiations and associated clinical features were compared among diabetic and non-diabetic groups by Pearson's Chi-square test.

DISCUSSION
The incidence of myocardial infarction (MI) is highest in South-Asia. 14 Around 90% of these cases have modifiable risk factors like diabetes, hypertension, smoking, etc. 2 Diabetic patients have a higher risk for MI and twice the short as well as long-term mortality after MI as compared to non-diabetic patients. [15][16][17] Chest pain is the commonest symptom experienced by patients but it can differ in nature and severity among diabetics and non-diabetics. 18 Atypical presentation and presentation without chest pain is also reported in diabetics. 9 Gradiser et al reported a majority of diabetic patients presenting with severe chest pain, however, 51.7% of diabetics had a mild or no pain at all. 7 Canto et al also reported a large number of diabetic patients with lack of chest pain. 19 21 Our study showed that 23.3% diabetic patients complaint of shortness of breath which could be due to late presentation in diabetics leading to poor left ventricular function. In our study, shortness of breath and syncope were in fact more commonly associated with diabetics compared to the other group, thus emphasizing the importance of recognizing atypical symptoms in non-diabetics. The findings of this study may contribute to the understanding that diabetic patients may have less severe symptoms and atypical presentations emphasizing the need for more care and vigilance during their evaluation for possible STEMI.

Limitations
The major limitation of this study is being a singlecenter cross-sectional survey conducted with limited sample size. Additionally, duration and control of diabetes and their potential impacts on chest pain severity and patterns were not accounted for. Future research on the subject may be conducted with multicenter larger study populations incorporating potential impacts of missing factors from this study.

CONCLUSION
Diabetics can frequently present without pain or with less severe chest pain and infrequent typical characters compared to non-diabetics and may have atypical symptoms like syncope and shortness of breath more commonly than non-diabetics.