Endocrine Abstracts

Background

Non-dipping of nocturnal blood pressure is common among people with type 2 diabetes (T2D) and hypertension. Although the mechanism underlying the blunted nighttime response is unclear, insulin resistance is thought to play a role.

Aims

This study aims to identify the pattern of nocturnal dipping of blood pressure in patients with T2D from a Portuguese population and its association with micro and macrovascular complications.

Methods

Data was collected from 197 patients with T2D and hypertension who had undergone 24 h ambulatory blood pressure (BP) monitoring. We assessed the correlations of different dipper profiles with the presence of diabetic complications. All statistical analyses were conducted using SPSS. Chi-square test was performed to evaluate the association between the variables. A P value ≤ 0.05 was considered to be significant.

Results

There were a total of 197 subjects (mean age 70) including 155 men and 42 women. The mean time since diagnosis of diabetes mellitus was 13.5 years. The prevalence of coronary artery disease (CAD), cerebrovascular disease, retinopathy and nephropathy was 20%, 13%, 9% and 29%, respectively. Normal dipping was observed in 33%, non-dipping in 39%, extreme dipping in 22% and 6% were risers. Regarding micro and macrovascular disease, 42% of dippers and extreme dippers presented at least one complication, versus 58% of non-dippers (P <0.05). Non dippers and risers were significantly older (P <0.01) with a higher prevalence of CAD (P = 0.03) and retinopathy (P = 0.05). No difference was found in other diabetes complications.

Discussion

Extreme dipping was found in more than a fifth of patients, reporting a higher prevalence than most studies. It has been proposed that extreme-dipping may have a significantly higher risk of silent myocardial ischemia. However, we found no increased risk of complications in this cluster. On the contrary, the prevalence of CAD in extreme dippers was 7% vs. 20% in dippers. Hypertension and nephropathy often coexist in patients with diabetes. Nonetheless, we did not observe any association between dipping status and nephropathy in this population. Our results indicate loss of nocturnal BP dipping as a risk factor for CAD and retinopathy in patients with T2D. This highlights the importance of ambulatory BP monitoring, particularly in the elderly population. Therefore, targeted antihypertensive therapy should be implemented in order to restore normal circadian BP in patients with T2D.