Decreased insulin sensitivity is associated with the extent of coronary artery disease in patients with angina

Background: Insulin resistance has been proposed as an important risk factor in the development of atherosclerosis. Aim: To evaluate the association of insulin resistance and coronary atherosclerosis, we investigated the correlation between insulin sensitivity and the degree of coronary stenosis in patients with angina pectoris. Methods: The study population consisted of 74 subjects with angina (54 men and 20 women) aged from 31 to 73 years. Coronary angiograms were evaluated by three semiquantitative scoring systems (vessel score, stenosis score and extent score) to estimate the extent of focal and diffuse coronary artery disease (CAD). Insulin sensitivity (K-ITT) was determined by the insulin tolerance test. Results: There were significant correlations existed between K-ITT and all three coronary scores. Multivariate analysis revealed significant and independent correlations of all three coronary scores with K-ITT (vessel score: beta = -0.349, p = 0.004; stenosis score: beta = -0.487, p < 0.001; extent score: beta = -0.481, p < 0.001), even in patients without diabetes mellitus (vessel score: beta = -0.387, p = 0.008; stenosis score: beta = -0.469, p < 0.001; extent score: beta = -0.559, p < 0.001). K-ITT was significantly lower in patient with diffuse CAD than without diffuse CAD (2.13 +/- 0.66 vs. 2.57 +/- 0.79%/min, p < 0.05). However, K-ITT was not different between patients with and without focal CAD. Conclusions: Insulin sensitivity has statistically significant and independent associations with the extent of coronary stenosis. These results suggest that insulin resistance may play a major role in the development of diffuse coronary artery stenosis.