Relationship between glucose response curve shape during the oral glucose tolerance test and macrovascular complications in type 2 diabetes mellitus.

Introduction: This study evaluated the predictive value of glucose response curve shape during the oral glucose tolerance test (OGTT) for macrovascular complications in patients with type 2 diabetes mellitus (T2DM).

Research design and methods: A retrospective observational analysis was conducted involving 75 subjects with normal glucose tolerance (NGT) and 496 patients with T2DM, all of whom underwent a 3-hour OGTT, along with insulin and C-peptide release tests. Multivariate linear regression models assessed the cross-sectional associations between glucose response curve shapes and common carotid artery (CCA) diameter and intima-media thickness (IMT) in T2DM patients. Risk factors for carotid atherosclerosis analyzed using multivariate logistic regression.

Results: Among patients with type 2 diabetes who underwent OGTT, the group with monophasic curves (n = 282) showed higher blood glucose levels, increased insulin resistance, and poorer pancreatic β-cell function compared to the multiphasic curve group (n = 214). Larger CCA diameters were independently associated with monophasic curves compared to multiphasic curves (regression coefficient: 0.134 [0.016, 0.252], P = 0.026). Increased IMT was independently associated with monophasic curves compared to multiphase curves (regression coefficient: 0.038 [0.001, 0.075], P = 0.045). Independent risk factors for carotid atherosclerosis in T2DM patients included monophasic curve (odds ratio [OR] 2.014, 95% confidence interval [CI] 1.300-3.121, P = 0.002), age (OR 1.040, 95% CI 1.020-1.059, P < 0.001), male sex (OR 2.107, 95% CI 1.364-3.256, P = 0.001), and duration of diabetes (OR 1.043, 95% CI 1.009-1.078, P = 0.012).

Conclusion: The shape of the glucose response curve during OGTT was significantly linked to the risk of macrovascular complications in T2DM patients. Those with monophasic glucose curves were at an elevated risk of developing such complications.