Endocrine Abstracts

In order to evaluate hypothalamic-pituitary-adrenal activity in diabetic patients in relation to neuroautonomic balance, we studied 50 consecutive hospitalized T2D patients (22F, 28M) without symptoms of neuropathy or hypercortisolism. We measured: morning, midnight and post-dexamethasone suppression cortisol (F8, F24 and F-Dex respectively) 24-hours urinary free cortisol (UFC), morning ACTH, systolic and diastolic blood pressure levels (SBP, DBP) and performed deep-breathing (DB), lying-to-standing (LS) and postural hypotension (PH) tests. Patients were subdivided according to the presence of parasympathetic (Group A, n=11), sympathetic (Group B, n=11), para- and sympathetic (Group C, n=9) dysfunction or the absence of autonomic failure (Group D, n=15). Age (whole group 58.2±9.3 yrs), BMI (whole group 30.3±4.9 kg/m²) and glycated haemoglobin (HbA_1C, whole group 10.3±2.2%) were comparable among the 4 groups.

HPA activity was significantly increased in Group A compared to Group D (UFC 48.6±21.4 vs 21.6±9.8 μg/24 h, P<0.0001; ACTH 27.0±8.6 vs 15.7±5.7 pg/dl, P<0.01; F8 20.4±4.5 vs 13.6±3.8 μg/dl, P<0.05; F-Dex 1.2±0.4 vs 0.8±0.6 μg/dl, P<0.05, respectively) and Group B (UFC 26.3±11.0 μg/24 h, P<0.0001; ACTH 19.9±8.0 pg/dl, P<0.05). SBP and DBP were significantly increased in Group A compared to Group D (SBP 136.4±16.8 vs 120.7±12.9 mmHg, P<0.01 and DBP 81.0±7.7 vs 74.0±6.1 mmHg, P<0.05 respectively) and Group B (SBP 123.3±14.6, P<0.05; DBP 75.5±7.2, P<0.05).

Values of DB and LS tests resulted to be correlated to UFC (r=−0.39, P=0.006; r=−0.46, P=0.009), SBP (r=−0.32, P=0.025; r=−0.30, P=0.04) and DBP (r=−0.28, P=0.046; r=−0.32, P=0.025). Multivariate linear regression analysis showed that UFC levels were significantly associated with parasympathetic neuronal dysfunction as reflected by LS test (β=−0.44, P=0.003) after adjusting for BMI, HbA_1C and disease duration. Asymptomatic diabetic autonomic unbalance is associated to increased activity of HPA axis and blood pressure levels, related to the degree of the neuronal dysfunction.