Glucose metabolism was investigated in 65 patients with Cushings syndrome (CS), 19 with cortisol-secreting adrenal adenoma (mean age 47.2±4.9), 40 with ACTH secreting pituitary adenoma (mean age 41.4±12.48), 4 with cortisol secreting adrenal cancer (mean age 63.0±8.4) and 2 patients with ectopic ACTH secretion (38.7±11.9).
Eleven patients (17%) were diagnosed as diabetic after abnormal fasting glucose levels (>126 mg/dl). While diabetes mellitus was diagnosed in other 22 patients (33%) only after abnormal oral glucose tolerance test (OGTT); 13 patients (20%) had impaired glucose tolerance at OGTT. Thus, basal glucose level were normal in 60% of diabetics and diabetes was diagnosed only after OGTT in ∼50% of the patients
There were no significant differences in anthropometric parameters, insulin levels, indexes of hypercortisolism and disease duration between patients with normal glucose metabolism (NGM) and patients with IGM.
|Mean±DS||NGM (n=19)||IGM (n=46)||P|
|Basal Glucose (mg/dl)||82.1±11.7||107.8±41.5||0.04*|
|120′ glucose post OGTT (mg/dl)||104.9±18.7||219.1±66.4||0.002*|
|Basal Insulin (μUI/ml)||16.5±8.5||13.1±7.5||0.20|
|Insulin peak at OGTT (μUI/ml)||119.6±75.2||138.8±59.5||0.63|
In a regression analysis, basal glucose levels were significantly positively correlated with plasma and urinary cortisol levels. Impaired glucose metabolism was present in 2/4 of the patients with cancers and in all patients with EC. No differences were found in lipid metabolism, blood pressure, sex and aetiology between NGM and IGM groups
In conclusion, our study shows that diabetes mellitus can be underestimated if only fasting blood glucose levels are considered. Thus, we recommend that OGTT be included in the evaluation of patients with hypercortisolism for a better estimation of the diseases complications and a better therapeutic management of the patient.
01 - 05 Apr 2006
European Society of Endocrinology