The association between post-load low insulin level and high mortality rates in patients with no previous diagnosis of diabetes mellitus

BackgroundHyperinsulinemia 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.MethodsData 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.ResultsThe 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.ConclusionsPost-load low insulin response is seen as a predictor of mortality rates for patients with no previous diagnosis of diabetes mellitus.