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