Patients in the metformin trial Patients in the first-phase screening were enrolled in the present trial if they had at least one of the following metabolic abnormalities: BMI ≥ 24; WC > 90 cm (men) or 80 cm (women); fasting serum TG level ≥ 150 mg/dL; fasting serum HDL-C level ≤ 40 mg/dL (men) or 50 mg/dL (women); systolic BP ≥ 130 or diastolic BP ≥ 85 mm Hg; current use of antihypertensive agents; and FPG level = 100-126 mg/dL. The exclusion criteria were the following: history of diabetes mellitus (DM); current use of hypoglycemic or hypolipidemic agents; pregnancy; allergy to metformin; a creatinine level > 1.4 ng/dL; an abnormal liver function test result; and chronic cardiopulmonary insufficiency.