BACKGROUND: Microalbuminuraia is a strong prognostic factor for cardiovascular morbidity and mortality in type I and II diabetics. Recent data suggest that microalbuminuria predicted cardiovascular disease independent of hypertension in one of two large-scale studies performed in non-diabetics. Additional possibilities could be a previously documented association with other major and interconnected cardiovascular risk factors, such as insulin resistance, and elevated cardiac mass, abnormal circulation lipid levels, and overweight. The object of this study os to investigat the incidence of microalbuminuria, and to define the pathophysiologic mechanism of microalbuminuria to contribute coronary heart disease in non-diabetic patients with angiographiclly documented coronary artery disease(CAD). METHODS: The study group comprised 31 patients(M;21, mean age 60+/-30 year) with angiographically documented CAD and 15 normal control(m;9, mean age 62+/-7 year). Urinary albumin excretion, blood pressure, echocardiographic left ventricular mass indes, plasma abdominal/hip circumference ratio, fasting glucose, insulin, and c-peptide were studied. The microalbuminuria was defined urinary albumin more than 20ug/min. RESULTS: 1) Six of 31 patients with CAD(19.4%) and none of 15 normal control had microalbuminuria. Hypertension were documented 13 of 31 patients with CAD, and none of 15 normal control(p<0.01). Five of 6 patients with CAD and microalbuminuria and 8 of 25 patients with non-microalbuminuric aptients had hypertension (p<0.05). 2) In the microalbuminuric subjects with CAD, body mass index(29.0+/-3.2vs 24.8+/-3.5), systolic blood pressure(138+/-31 vs 118+/-15mmHG), lipoprotein(a) (69+/-31vs 32+/-32mg/dl), fastion C-peptide(5.5+/-2.2 vs 2.7+/-1.6ng/ml), and microalbumin(221+/25 vs 9.6+/-7.9mg/day)were significantly greater than in normal control(p<0.05). But no difference in left ventricular mass, lipid profile, and abdominal/hip circumference ratio existed between the microalbminuric patients with CAD and normal control. 3) Between the microalbuminuric patients with CAD and without CAD, no signficant difference were noted excepr lipoprotein(a) lever(69+/-31 vs 29+/-29mg/dl), fasting C-peptide(5.5+/-2.4 vs 2.5+/-1.2ng/ml), and microalbumin(221+/-247 vs 8.6+/-6.7mg/day). CONCLUSION: Microalbuminuria was associated with history of hypertension or concurrent antihypertension therapy and insulin resistance in non-diabetics with CAD. But left ventricular cardiac mass, central obesity inedw, and lipid profile were not related with microalbuminuria. The underlying presence of a major risk factor such as hypertension and insulin resistance might be explain the previously reported predictive value of microalbuminuria for cardiac events.