Relations of Epicardial Adipose Tissue Volume, Thyroid Axis Hormones and Microalbuminuria to Coronary Artery Calcium in Type 2 Diabetic Patients

Abstract

Cardiovascular disease is the major cause of morbidity and mortality in people with type 2 diabetes and the largest contributor to the direct and indirect costs of diabetes (American Diabetic Association, 2014). Moreover, compared with people without diabetes; those with type 2 diabetes have a higher risk of mortality at comparable levels of coronary artery disease (Rana et al., 2012). Epicardial adipose tissue (EAT) is a metabolically active visceral fat deposit found around the heart, between the pericardium and myocardium, and there is a growing evidence suggests that EAT has clinical relevance in that it influences the development and progression of coronary artery disease (Kim et al., 2012). The coronary artery calcium score has been shown to predict the risk for cardiovascular events (Kramer et al., 2013). Microalbuminuria has long been recognized as an important biomarker to predict micro- and macrovascular complications and mortality for patients with T2DM and also considered an independent predictor of cardiovascular and all cause mortality in patients with or without diabetes (Lall et al., 2012). The aim of this study was to investigate the relations of epicardial adipose tissue volume, thyroid axis hormones and microalbuminuria to coronary artery calcificium in type 2 diabetic patients.

This study was conducted on 100 type 2 diabetic patients; they were divided into two groups: Group 1: 50 diabetic patients with microalbuminuria who were subdivided into:  Subgroup 1a: 25 obese diabetic patients with microalbuminuria.  Subgroup 1b: 25 lean diabetic patients with microalbuminuria. Group 2: 50 diabetic patients with normoalbuminuria who were subdivided into:  Subgroup 2a: 25 obese diabetic patients with normoalbuminuria.  Subgroup 2b: 25 lean diabetic patients with normoalbuminuria. Inclusion Criteria:  Age: 40-60 years old.  Type 2 diabetic patients. Exclusion Criteria:  Previous history of coronary artery disease.  Previous history of any thyroid disorder.  Pregnant female.  Patients with renal or hepatic failure. All patients of this study were subjected to full medical history, thorough medical examination, fasting and 2 hours plasma glucose during OGTT, hemoglobin A1c, fasting serum lipid profile (total cholesterol, LDL cholesterol, HDL cholesterol and triglycerides), fasting serum insulin, albumin creatinine ratio, free T3, free T4, TSH and Coronary multi-slice CT scanning to detect coronary artery calcium score and epicardial adipose tissue volume.

In conclusions; the present study revealed that:  Type 2 diabetic patients with microalbuminuria had higher prevalence of dyslipidemia than those with normoalbuminuria and had also higher levels of total cholesterol, LDL-C, non-HDL-C and triglycerides.  Type 2 diabetic patients with microalbuminuria had higher epicardial adipose tissue volume than those with normoalbuminuria and EAT was directly correlated to UACR.  Type 2 diabetic patients with microalbuminuria had higher coronary artery calcium than those with normoalbuminuria and CAC was directly correlated to UACR.  Type 2 diabetic patients with microalbuminuria had poor blood glucose control and higher insulin resistance than those with normoalbuminuria.  Type 2 diabetic patients with microalbuminuria had lower free T3 and higher TSH than those with normoalbuminuria.  Type 2 diabetic patients with higher coronary artery calcium had higher total cholesterol, LDL, non-HDL and triglycerides with significant direct correlations.  Type 2 diabetic patients with higher coronary artery calcium had worse blood glucose control with significant direct correlations with FPG, 2h PG OGTT, HbA1C and also patients with coronary artery calcium had more insulin resistance than those without coronary artery calcium with significant direct correlation.  Type 2 diabetic patients with higher coronary artery calcium had lower free T3 level and higher TSH level.  Type 2 diabetic patients with higher coronary artery calcium had higher epicardial adipose tissue and epicardial adipose tissue was an independent risk factor for coronary artery calcium regardless BMI.  Epicardial adipose tissue was directly correlated to BMI, total cholesterol, LDL, non-HDL and triglycerides.  Epicardial adipose tissue was indirectly correlated to plasma glucose control and directly correlated to insulin resistance.  Epicardial adipose tissue was indirectly correlated to free T3 and directly correlated to TSH.  Epicardial adipose tissue and UACR were the most important predictors of CAC.  Coronary artery calcium and hemoglobin A1C were the most important predictors of EAT.