Aim was to evaluate frequency of postoperative hypocortisolism and predictors of recovery in NAPAA patients after unilateral adrenalectomy.
A retrospective study on 32 adrenal incidentaloma patients with NAPAA undergoing surgery was conducted. Preoperative assessments: MRI, anthropometrics, comorbidities, adrenal function (ACTH, urinary-free-cortisol, and 1 mg dexamethasone suppression test [p-DST]). ACTH, serum cortisol or Short Synacthen test (SST) performed at 6-days, 6-weeks, 6-months, and one year after surgery.
At six days, 18.8% patients had normal adrenal function. 53.8% patients with postoperative hypocortisolism recovered at 6-weeks. Patients with earlier adrenal recovery had lower p-DST (median 76.2 nmol/L vs 260.0 nmol/L, p < 0.001). Univariate analysis: p-DST negatively related with baseline ACTH levels (r = -0.376; p= 0.041) and negatively associated with 6-weeks (r= -0.395, p=0.034) and 30-minutes cortisol levels during SST (r= -0.534, p=0.023). Logistic regression analysis: p-DST was the only biochemical predictor of 6-weeks adrenal recovery. ROC curve identified a p-DST threshold of 131 nmol/L predicting 6-weeks recovery with 89.5% sensitivity and 72.7% specificity (AUC 0.87; 95%CI, p < 0.001). Tumor size, ACTH levels and anthropometrics were not related with postoperative hypothalamus-pituitary-adrenal (HPA) axis function, but diabetes coupled with a lower probability of recovery (OR=24.55, p=0.036). ACTH levels increased in all patients but did not predict HPA axis recovery.
P-DST cortisol value and diabetes are the only relevant predictors of HPA axis recovery in NAPAA patients undergoing surgery, regardless of other clinical and biochemical variables. Pre-postoperative ACTH levels did not predict HPA axis recovery. These findings may save resources' allocation during follow-up.