Blood pressure pattern and heart rate variability in normotensive patients with type 2 diabetes mellitus

Ambulatory blood pressure monitoring (ABPM) has shown that almost one third of presumed normotensive patients with type 2 diabetes mellitus have instead masked hypertension. There is also a relationship between cardiovascular autonomic neuropathy and blood pressure patterns even in normotensive patients with diabetes mellitus. The aim of the present study was to analyze the blood pressure patterns in type 2 diabetic patients without any history of hypertension and to establish the connection between heart rate variability parameters, ultrasound parameters and ABPM parameters.

Fifty-two subjects with type 2 diabetes, aged 59 (+/- 6), were consecutively recruited at the Internal Medicine Department of the County Hospital in Cluj. Informed consent was obtained from all participants. A control group of 47 subjects, age and sex matched, was also analyzed.

More than half of the patients had a non-dipping pattern, despite the fact that they are considered normotensive patients. Heart rate variability parameters are lower in the non-dipping group, but the difference is significant only for vagal activity. Left ventricle is thicker in non-dipping group. The mean age of the non-dipping group (61.23 +/- 2.02 years) was significantly higher than the age of the dipping group (55.11 +/- 3.88 years) (p < 0.01).

We found a great number of patients with diabetes mellitus and with altered patterns of blood pressure, even if they were previously considered as normotensive. The non-dipping pattern is associated with abnormal values of heart rate variability parameters and with thicker left ventricle walls, but the differences are not always statistically significant. It is important to closely monitorize the patients with diabetes mellitus even if they have normal office blood pressure determinations, mainly those with a history of more than 5 years of the disease.