This cohort study will measure how severe is the coronary artery disease (CAD), at time of CAD diagnosis, clinically and angiographically in the different cohorts of newly diagnosed diabetes and prediabetes versus normal glycemia patients in the study center.

Inclusion Criteria:

• All adult patients with consents.
• First time diagnosis of CAD and no prior diagnosis of diabetes milletus (DM), or prediabetes.
• Coronary artery disease confirmed by invasive coronary angiography.

Exclusion Criteria:

1. Patients with known significant anemia, increased hemoglobin turnover, active hemoglobin drops or on erythropoietin therapy.
2. Pregnant and post-partum patients (up to 3 months post-delivery).
3. Patients with severe chronic renal failure (estimated glomerular filtration rate (eGFR) < 30 mL/min/1.72 m2).
4. Patients on any medications with glucose lowering effects.

A single center cohort study, where all comers, adult patients without prior diagnosis of DM, who are admitted with a first-time diagnosis of CAD, as confirmed by invasive coronary angiography, either elective or as emergency, will be eligible. The study will prospectively enroll consecutives and contemporary cases for each group of diabetes, pre-diabetes and normal glycemia.