Association between glycemic control and morning blood pressure surge with vascular endothelial dysfunction in type 2 DM patients

Objective: Morning blood pressure surge (MBPS) is an independent predictor of cardiovascular events. However, little is known on the association between glycemic control and MBPS and its effect on vascular injury in patients with type 2 diabetes mellitus (T2DM). The present study examined the association between glycemic control and MBPS and the involvement of MBPS in the development of vascular dysfunction in T2DM patients. Research Design and Methods: We examined MBPS in T2DM patients (M/F; 25/25, age; 60.1±13.2 years, n=50) by 24-hour ambulatory blood pressure monitoring, and assessed vascular function by brachial artery flow-mediated dilation (FMD) and nitroglycerinmediated dilation (NMD). Results: HbA1c (ρ=0.373, p=0.009) and triglyceride (ρ=0.375, p=0.009) correlated significantly and positively with MBPS. In multiple regression analysis including triglyceride and HbA1c in addition to age, 24-hour systolic blood pressure (24h-SBP) as independent variables, HbA1c (β=0.328, p=0.016) and triglyceride (β=0.358, p=0.014) associated significantly in a positive manner with MBPS. In non-insulin user, when HOMA-R was included in place of TG, HOMA-R emerged as a significant factor. MBPS (ρ=-0.289, p=0.043), and HbA1c (ρ=-0.301, p=0.035) correlated significantly and negatively with FMD, while 24h-SBP correlated with both FMD (ρ=-0.359, p=0.012) and NMD (ρ=-0.478, p=0.004). In multiple regression analysis, including age, gender, 24h-SBP, MBPS, LDLcholesterol, and HbA1c, MBPS (β=-0.284, p=0.044) alone associated significantly in a negative manner with FMD, but not with NMD. Conclusions: The present study demonstrated that poor glycemic control and insulin resistance are independently associated with the occurrence of MBPS in T2DM patients, which might be significantly associated with endothelial dysfunction.