Baroreflex sensitivity is depressed in microalbuminuric Type I diabetic patients at rest and during sympathetic manoeuvres

To evaluate baroreflex sensitivity (BRS) in microalbuminuric and normoalbuminuric Type I (insulin-dependent) diabetic patients without autonomic neuropathy and in healthy control subjects.

Microalbuminuric Type I diabetic patients (n = 15) were matched for age, sex, body mass index (BMI) and smoking habits with 15 normoalbuminuric patients and with 15 healthy control subjects. All subjects had a blood pressure less than 160/95 mmHg, a BMI less than 30 kg/m(2) and normal autonomic function on standard tests. Blood pressure and heart rate were measured non-invasively (Finapres) at rest and during sympathetic activation (handgrip, mental stress, standing). The baroreflex sensitivity was defined as the mean gain between blood pressure variability and heart rate variability in the 0.07-0.15 Hz frequency band.

Resting baroreflex sensitivity was decreased in the microalbuminuric patients (3.5 +/- 0.4 ms/mmHg) compared with the normoalbuminuric patients and the healthy subjects (7.6 +/- 1.6 and 9.5 +/- 1.1 ms/mmHg, respectively, p < 0.001). The sympathetic tests reduced baroreflex sensitivity similarly in the groups without changing the between group differences.

Baroreflex sensitivity is reduced in Type I diabetic patients with microalbuminuria but without autonomic neuropathy. A prospective study should indicate whether this early abnormality in cardiovascular reflex function is a risk factor of cardiovascular mortality in these patients. [Diabetologia (1999) 42: 1345-1349]