Presence of subclinical hypercortisolism in clinical aldosterone-producing adenomas predicts lower clinical success

The clinical characteristics and outcomes in patients with clinical aldosterone-producing adenomas harboring KCNJ5 mutations with or without subclinical hypercortisolism remain unclear. This prospective study is aimed at determining factors associated with subclinical hypercortisolism in patients with clinical aldosterone-producing adenomas. Totally, 82 patients were recruited from November 2016 to March 2018 and underwent unilateral laparoscopic adrenalectomy with at least a 12-month follow-up postoperatively. Standard subclinical hypercortisolism (defined as cortisol >1.8 μg/dL after 1 mg dexamethasone suppression test [DST]) was detected in 22 (26.8%) of the 82 patients. Intriguingly, a generalized additive model identified the clinical aldosterone-producing adenoma patients with 1 mg DST>1.5 μg/dL had significantly larger tumors (P=0.02) than those with 1 mg DST<1.5 μg/dL. Multivariable logistic regression showed that the presence of KCNJ5 mutations (odds ratio, 0.22, P=0.010) and body mass index (odds ratio, 0.87, P=0.046) were negatively associated with 1 mg DST>1.5 μg/dL, whereas tumor size was positively associated with it (odds ratio, 2.85, P=0.014). Immunohistochemistry revealed a higher degree of immunoreactivity for CYP11B1 in adenomas with wild-type KCNJ5 (P=0.018), whereas CYP11B2 was more commonly detected in adenomas with KCNJ5 mutation (P=0.007). Patients with wild-type KCNJ5 and 1 mg DST>1.5 μg/dL exhibited the lowest complete clinical success rate (36.8%) after adrenalectomy. In conclusion, subclinical hypercortisolism is common in clinical aldosterone-producing adenoma patients without KCNJ5 mutation or with a relatively larger adrenal tumor. The presence of serum cortisol levels >1.5 μg/dL after 1 mg DST may be linked to a lower clinical complete success rate.