Background: Hyperinsulinemia and insulin resistance have been proposed as having a causal role in pathogenesis of atherosclerosis; however, the relationship between post-load insulin levels and long-term survival is not clear. We investigated whether post-load insulin response is a predictor of outcome in patients without previously recognized diabetes.
Methods: Data from 933 Japanese patients who underwent both a 75 g oral glucose tolerance test and coronary angiography with suspected coronary artery disease were analyzed. The determinant factors in association with all-cause death or cardiovascular events, including reinfarction, heart failure or angina requiring re-hospitalization, and coronary revascularization were examined by multivariate Cox regression analysis.
Results: The numbers of patients with normal glucose tolerance, impaired glucose regulation and diabetes were 326, 408 and 199, respectively. During the follow-up period (median 1113 days), death occurred in 37 patients including 13 cardiac causes. There were no significant differences in mortality or cardiovascular event incidence between glucose tolerance status. Kaplan-Meier curves indicated that the lower-response group of 2-hour insulin levels (<75.3 mU/L; median) was associated with higher mortality rates (Log-rank P=0.006). Multivariate Cox regression analysis revealed that 2-hour insulin level was an independent predictor of all-cause death (P=0.026) after adjustment for age, gender, number of stenosed vessels, ejection fraction, metabolic factors, and treatments.
Conclusions: Post-load low insulin response is seen as a predictor of mortality rates for patients with no previous diagnosis of diabetes mellitus.
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