Concomitant alterations of metabolic parameters, cardiovascular risk factors and altered cortisol secretion in patients with adrenal incidentalomas during prolonged follow-up.

OBJECTIVE: Adrenal incidentalomas (AI) are associated with metabolic and hormonal abnormalities, most commonly autonomous cortisol secretion (ACS). Data regarding alterations of insulin resistance (IR) and ACS after prolonged follow-up are limited. We investigated the evolution of IR, cortisol secretion and ACS development in patients with AI during prolonged follow-up.
DESIGN: Prospective study in a tertiary hospital. PATIENTS AND MEASUREMENTS: Seventy-one patients with AI [51 nonfunctioning (NFAI) and 20 ACS] and 5·54 ± 1·7 years follow-up underwent testing for ACS and oral glucose tolerance test to determine IR indices and adrenal imaging.
RESULTS: At follow-up, 16/51 (31%) NFAI patients converted to ACS, while two with previous ACS reverted to NFAI; 21% (7/33) of patients who did not covert to ACS exhibited high urinary-free cortisol (H-UFC) levels. All AI patients developed deterioration of IR irrespective of their cortisol secretory status. Eight patients developed newly diagnosed type 2 diabetes (9·8% NFAI and 15% ACS, respectively) and 14 IR (17·6% NFAI and 25% ACS, respectively). Adenoma size increased from 2·1 ± 0·8 to 2·3 ± 0·8 cm, whereas IR correlated with postdexamethasone cortisol level and adenoma size increase. IR showed an incremental continuum trend from normal UFC (Ν-UFC), to H-UFC, C-ACS and ACS patients.
CONCLUSIONS: New-onset ACS developed in 31% patients with NFAI, whereas 21% of NFAI patients had H-UFC levels. All AI patients as a group and the subgroups of N-UFC, H-UFC, C-ACS and ACS patients developed deterioration of metabolic parameters during follow-up that was more prominent in ACS patients.