Introduction Coronary artery disease is the leading cause of death worldwide by incidence. Over the years, many studies have been conducted to find predictors of coronary artery disease; however, in the last few decades, the level of HbA1c in diabetics has been investigated as a potential predictor. Our study offers additional insight by investigating similar relationships in non-diabetic patients and by investigating potential predictors more comprehensively, making it the first of its kind study. The aim of our study is to indicate that rising HbA1c levels suggest that there's a greater risk of coronary artery disease, which can further be confirmed by the SYNTAX score, degree of stenosis, and numbers of vessels involved. Methods Data from 177 diabetic and 378 non-diabetic patients, all of whom were above 18 years of age, were included in the research. HbA1c levels (>5.6%), SYNTAX score, hypertension, number of vessels involved, and other demographic elements, such as age, smoking, and body measurements, were calculated and compared for diabetics and non-diabetics. Results HbA1c was higher in comparison to non-diabetic subjects (p <0.001). Age >53 was found to be a predictor for SYNTAX score ≥23 in diabetic patients (p <0.05). Male gender and smoking were found to be independent predictors for three-vessel disease in the non-diabetic population (p-value<0.05). There was no significant relationship between the SYNTAX score and HbA1c levels in non-diabetics (p=0.885) and diabetics. In conclusion, there is no correlation between elevated HbA1c levels and SYNTAX score ≥23.