Left ventricular hypertrophy (LVH) is a recognized independent risk factor for cardiovascular morbidity and mortality. The purpose of this study was to assess the determinants of left ventricular mass index (LVMI), according to the presence or absence of silent myocardial ischaemia (SMI), in diabetic patients with at least two additional risk factors but with no known coronary artery disease. Eighty diabetic patients (14 Type 1 and 66 Type 2) were studied, and LVMI was measured echocardiographically. Three non-invasive tests (the ECG stress test, thallium-201 myocardial scintigraphy with intravenous dipyridamole infusion, and ambulatory 48-h ECG monitoring) were performed on all patients. Forty-five percent of patients had LVH (LVMI > or = 110 g/m2 in men and > or = 106 g/m2 in women). Twenty-six patients (37%) had SMI assessed on at least one of the non-invasive tests, 7 of whom had significant coronary stenoses on angiography. LVMI was significantly higher in patients with coronary stenoses on angiography than in those with SMI but without coronary stenoses or in those without SMI (p < 0.05), and was correlated with systolic blood pressure. In patients free of SMI, LVMI correlated with creatininemia. In patients with SMI and normal coronary arteries on angiography, LVMI correlated with the waist/hip girth ratio, the log urinary albumin excretion rate and the red blood cell filtration index (a rigidity index). This study suggests that LVH is very frequent in diabetic patients and that the main factor contributing to the increase of LVMI differs according to the presence or absence of SMI and coronary stenoses: volume load in patients free of SMI, microcirculatory disorders in those with SMI but with normal coronary arteries, and blood pressure in those with coronary stenoses.