en Internal Internal Original Article Original Article <span style="font-size:14px;"><span style="font-family:Times New Roman;"><span style="line-height:14pt"><b><i><span style="color:blue">Background</span></i></b><i><span style="color:blue">:</span></i> Insulin resistance (IR) examined by homeostasis model assessment of insulin resistance (HOMA-IR) measures increased carotid atherosclerosis risks in non-diabetic and non-obese persons. The information about the relationship between IR and coronary atherosclerosis severity among non-diabetic and non- obese population showed conflicting results. The goal of the current study was to assess the relationship that links IR and coronary artery disease (CAD) among non-diabetic and non-obese Egyptian populations.</span><br> <span style="line-height:14pt"><b><i><span style="color:blue">Methods:</span></i></b> 112 non-diabetic and non-obese patients were included in this study. These patients underwent coronary angiogram (CA) either due to acute coronary syndrome (ACS) or chronic stable angina with positive exercise tests.<span style="font-size:10.0pt"></span></span><br> <span style="line-height:14pt"><b><i><span style="color:blue">Results:</span></i></b> Our study found a strong association between HOMA-IR and Gensini score (r = 0.831,&nbsp;with p<0.001) in general population. The HOMA-IR was the most influential independent predictor for the presence of extensive coronary atherosclerosis. Non-diabetic and non-obese people carrying the risk of developing the three-vessel disease (3VD) may be identified with a HOMA-IR score of over 5.9 according to the ROC curve analysis with a sensitivity of 67.7%.<span style="font-size:10.0pt"></span></span><br> <span style="line-height:14pt"><b><i><span style="color:blue">Conclusion</span></i></b><i><span style="color:blue">:</span></i> IR that developes in non-diabetic non-obese individuals coincides with more severe and more outspread CAD. In non-diabetic non-obese populations who need a CA, a single HOMA-IR value is higher than 5.9 may imply an elevated risk for clinically significant CAD. As insulin resistance is a reversible process, risk stratifications of CAD in non-diabetic non-obese populations could include HOMA-IR as one of its parameters.<span style="font-size:10.0pt"></span></span></span></span><br> <br> <span style="font-size:12pt"><span style="line-height:150%"><span new="" roman="" style="font-family:" times=""><strong><span style="color:#0e101a"><span style="font-weight:normal"></span></span></strong></span></span></span> Coronary Artery Disease, Coronary Atherosclerosis, HOMA estimated Insulin resistance. 495 506 http://caspjim.com/browse.php?a_code=A-10-2723-1&slc_lang=en&sid=1 Mohamed Eid moh.eid1979@gmail.com 100319475328460043034 100319475328460043034 Yes Department of Internal Medicine, Faculty of Medicine, Sohag University, Sohag, Egypt Sherif A. Sayed Shereefaziz_2@yahoo.com 100319475328460043035 100319475328460043035 No Department of Clinical Pathology, Faculty of Medicine, Sohag University, Sohag, Egypt Nayel A. Zaki Nayelzaki@gmail.com 100319475328460043036 100319475328460043036 No Department of Internal Medicine, Faculty of Medicine, Sohag University, Sohag, Egypt Amera M. F. Hamdy ameramoradfoad@gmail.com 100319475328460043037 100319475328460043037 No Department of Medical Biochemistry, Faculty of Medicine, Sohag University, Sohag, Egypt Ali M. A. Altaher dr.ali.altaher30@gmail.com 100319475328460043038 100319475328460043038 No Department of Internal Medicine, Faculty of Medicine, Sohag University, Sohag, Egypt.