Spontaneous baroreflex sensitivity in subjects with type 1 diabetes with and without cardiovascular autonomic neuropathy.

Introduction: The clinical usefulness of baroreflex sensitivity (BRS) in the early detection of autonomic dysfunction in patients with diabetes is not well established. The aim of the study was the evaluation of BRS in subjects with type 1 diabetes with and without cardiovascular autonomic neuropathy (CAN).

Material And Methods: The group examined consisted of 39 patients with type 1 diabetes (mean age 30.5 +/- 8.8 years; diabetes duration 12.1 +/- 6.9 years; BMI 23.7 +/- 2.8 kg/m2; HbA(1c) 7.6 +/- 1.9%). The control group consisted of 18 sex and age-matched healthy adults. Blood pressure, heart rate and chest respiratory movements were monitored continuously by non-invasive means (Portapres). In order to recognise CAN standard Ewing tests were performed. BRS was assessed in the lying (L-BRS) and standing (S-BRS) positions by the frequency domain technique.

Results: Ten patients (25.6%) had CAN (the CAN(+) group). In the CAN(+) group BRS was significantly lower than in the CAN(-) group in the lying and standing positions (respectively L-BRS 4.4 +/- 2.1 vs. 10.0 +/- 4.9 ms/mm Hg; p < 0.05; S-BRS 3.3 +/- 1.6 vs. 7.0 +/- 2.2 ms/mm Hg p < 0.001). BRS did not differ significantly between the CAN(-) and control group (respectively L-BRS 10.0 +/- 4.9 vs. 13.1 +/- 5.5 ms/mm Hg p = NS; S-BRS 7.0 +/- 2.2 vs. 7.9 +/- 4.0 ms/mm Hg p = NS).

Conclusions: BRS differentiated well the subjects with CAN from the group without CAN. However, the study did not enable us to confirm the value of BRS in the early detection of autonomic dysfunction among patients with type 1 diabetes who showed no abnormalities in standard cardiovascular tests.