Accuracy of several parameters of hypothalamic-pituitary-adrenal axis activity in predicting before surgery the metabolic effects of the removal of an adrenal incidentaloma.
CONTEXT
It is unknown whether the metabolic effects of the removal of an adrenal incidentaloma (AI) can be predicted by the assessment of cortisol hypersecretion before surgery.


OBJECTIVE
To evaluate the accuracy of several criteria of hypothalamic-pituitary-adrenal axis activity in predicting the metabolic outcome after adrenalectomy.


DESIGN
Retrospective longitudinal study.


PATIENTS
In 55 surgically treated AI patients (Group 1) before surgery and in 53 nontreated AI patients (Group 2) at the baseline, urinary free cortisol (UFC), cortisol after 1 mg overnight dexamethasone-suppression test (1 mg-DST), ACTH, and midnight serum cortisol (MSC) were measured. In Groups 1 and 2, metabolic parameters were evaluated before and 29.6 ± 13.8 months after surgery and at the baseline and after 35.2 ± 10.9 months respectively.


MAIN OUTCOME MEASURES
The improvement/worsening of weight, blood pressure, glucose, and cholesterol levels (endpoints) was defined by the presence of a >5% weight decrease/increase and following the European Society of Cardiology or the ATP III criteria respectively. The accuracy of UFC, 1 mg-DST, ACTH, and MSC, singularly taken or in combination, in predicting the improvement/worsening of ≥ 2 endpoints was calculated.


RESULTS
The presence of ≥ 2 among UFC>70 μg/24 h (193 nmol/l), ACTH<10 pg/ml (2.2 pmol/l), 1 mg-DST>3.0 μg/dl (83 nmol/l) (UFC-ACTH-DST criterion) had the best accuracy in predicting the endpoints' improvement (sensitivity (SN) 65.2%, specificity (SP) 68.8%) after surgery. In the nontreated AI patients, this criterion predicted the worsening of ≥ 2 endpoints (SN 55.6%, SP 82.9%).


CONCLUSIONS
The UFC-ACTH-DST criterion seems to be the best for predicting the metabolic outcome in surgically treated AI patients.