Endocrine Abstracts

Background: It has been hypothesized that patients with type 2 diabetes mellitus (DP) are very suspicious to have hypercortisolism, especially those which a high HbA1c level. The prevalence of hypercortisolism also could be high in obese patients (OP).

Methods: To 111 DP (male:female, 1:3; 58 (50; 64) years old; HbA1c, 9.5±2.2%), and 39 OP (male:female 2:1, 22 (20; 28) years old) 1 mg dexamethasone suppression test (DST-1) have been done. If post-DST-1 cortisol level was >50 nmol/l (positive result), the 2 mg/day for 48 h dexamethasone suppression test (DST-2) was made. If cortisol level exceeded 50 nmol/l after DST-2 (positive), subclinical hypercortisolism (SH) was suspect, and MRI, MSCT were done.

Results: Positive results was found in 39% of OP after DST-1 and reduced to 10% after DST-2. Only in one case (25%) abnormality was found (pituitary adenoma). In DP positive results was found in 42% of cases after DST-1 and reduced to 11% after DST-2. Among DP with positive DST-2 we incidentally revealed two patients with overt hypercortisolism (confirmed thereafter). Most (75%) of the DP and OP with SH had post-DST-2 cortisol level between 50 and 140 nmol/l. At the same time two patients with overt hypercortisolism had post-DST-2 cortisol level >140 nmol/l. There were no differences between HbA1c level in DP with negative and positive DST-1 and DST-2 (P=0.3). We made seven groups of DP depending on their HbA1c level. We did not find any differences in percent of patients with SH between groups. UFC and morning serum cortisol levels were higher in DP than in OP (P<0.05). Because DP were significantly older than OP (P<0.05), the two groups matched on age and BMI were created. Only the morning serum cortisol level was still higher on DP (P=0.04).

Conclusion: Diabetic patients are highly suspicious on subclinical and also overt hypercortisolism. In some of them even overt hypercortisolism can be missed. Obese patients also had high percentage of SH, but the group was small. The cut-off level of post-DST-2 cortisol 140 nmol/l can miss a lot of patients with SH.