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

Aims/hypothesis. To evaluate baroreflex sensitivity (BRS) in microalbuminur ic and normoalbuminuric Type I (insulin-dependent) diabetic patients withou t autonomic neuropathy and in healthy control subjects. Methods. Microalbuminuric Spe I diabetic patients (n = 15) were matched for age, sex, body mass index (BMI) and smoking habits with 15 normoalbuminuri c patients and with 15 healthy control subjects. All subjects had a blood p ressure less than 160/95 mmHg, a BMI less than 30 kg/m(2) and normal autono mic function on standard tests. Blood pressure and heart rate were measured non-invasively (Finapres) at rest and during sympathetic activation (handg rip, mental stress, standing). The baroreflex sensitivity was defined as th e mean gain between blood pressure variability and heart rate variability i n the 0.07-0.15 Hz frequency band. Results. Resting baroreflex sensitivity was decreased in the microalbuminur ic patients (3.5 +/- 0.4 ms/mmHg) compared with the normoalbuminuric patien ts and the healthy subjects (7.6 +/- 1.6 and 9.5 +/- 1.1 ms/mmHg, respectiv ely, p < 0.001). The sympathetic tests reduced baroreflex sensitivity simil arly in the groups without changing the between group differences. Conclusion/interpretation. Baroreflex sensitivity is reduced in Type I diab etic patients with microalbuminuria but without autonomic neuropathy. A pro spective study should indicate whether this early abnormality in cardiovasc ular reflex function is a risk factor of cardiovascular mortality in these patients.