Aim of the work: this study aimedto explore the association between diabetes duration on both the extent and severity of coronary atheroma burden using coronary computed tomography angiography (CCTA) in type 2 diabetic patients. Patients and methods: we analyzed 105 symptomatic type 2 diabetic patients without known CAD who underwent CCTA from August 2016 to June 2017. Patients were categorized into two groups according to the duration of diabetes: < 10 years, and ≥ 10 years. Stenosis by CCTA was scored as none (0%), non-obstructive (1–49%), or obstructive (≥50%) for each coronary artery segment. For these patients, we compared the prevalence, extent, and severity of CAD, including coronary artery calcium score (CACS), atheroma burden obstructive score (ABOS), segment involvement score (SIS), segment stenosis score (SSS) and syntax score. Results: patients with longer duration of type 2 diabetes possessed higher rates of obstructive CAD. Patients with longer duration of diabetes also manifested greater degree of CACS, ABOS, SIS, SSS and syntax score (P < 0.001 for all). Conclusion: in symptomatic type 2 diabetic patients, longer diabetes duration was associated with a higher prevalence, extent, and severity of CAD so, increased risk of developing atherosclerotic cardiovascular disease including major events as myocardial infarction or even sudden cardiac death.  
INTRODUCTION Reducing atherosclerotic cardiovascular disease (ASCVD) burden in diabetes mellitus (DM) is a major clinical imperative that should be prioritized to reduce premature death, improve quality of life and lessen individual and economic burdens of associated morbidities, decreased work productivity, and high cost of medical care ^[1]. Atherosclerotic cardiovascular disease remains the principal cause of death and disability among patients with diabetes mellitus, especially in those with type 2 diabetes mellitus in whom it typically occurs 14.6 years earlier ^[2], with greater severity, and with more diffuse distribution than in individuals without diabetes mellitus ^[3]. Furthermore, about two-thirds of deaths in people with diabetes mellitus are attributable to cardiovascular disease: of these, ≈ 40% are from ischemic heart disease, 15% from other forms of heart disease, principally congestive heart failure, and ≈10% from stroke. Among those with diabetes mellitus, excess risks of death from any cause and of ASCVD mortality are particularly prominent in those with younger age, higher burden of glycaemia, and greater renal complications, in comparison with those without ^[4].  Although the incidences of diabetes mellitus–related complications including cardiovascular disease have decreased over the past 2 decades, patients with diabetes mellitus continue to have significantly increased risk for vascular complications in comparison with individuals without diabetes mellitus ^[5]. An estimated 382 million people worldwide have diabetes mellitus and this number is expected to reach 592 million by the year 2035 ^[6]. Key manifestations of ASCVD in diabetes mellitus included advanced atherosclerosis manifest as coronary artery disease (CAD), ischemic stroke, peripheral vascular disease, and heart failure. Understanding the mechanisms, strategies for and challenges with managing ASCVD and heart failure risk in diabetes mellitus, as well as the potential cardiovascular risks and benefits of glucose-lowering drugs, is important for managing cardiovascular disease in diabetes mellitus ^[1]. Coronary computed tomography angiography (CCTA) has emerged as a non-invasive imaging modality for the detection or exclusion of CAD, with prior studies observing a high prevalence of CAD in asymptomatic type 2 diabetic patients using CCTA that is associated with worsened outcomes ^[7]. A