Endocrine Abstracts

Introduction: For defining SH in AI patients at least 2 altered criteria among serum cortisol after 1 mg dexamethasone test (1 mgDST), ACTH levels, 24 h urinary free cortisol (UFC) and midnight serum cortisol levels are generally required. Midnight salivary cortisol (MSC), a sensitive and easy-to-perform marker of overt hypercortisolism, appears to be of limited utility in these patients. Data on the role of salivary cortisol using LC-MS/MS, the gold standard procedure for steroids measurement, are lacking.

Methods/design: In 50 AI patients (F/M 27/23) we evaluated morning salivary cortisol (CS8, normal values. 1.5–15 nmol/L), salivary cortisol after 1mg-DST (Sa-DST, cut-off <1.2 nmol/L), MSC (cut off <2.8 nmol/L) using LC-MS/MS, serum cortisol after 1 mgDST (Se-DST), UFC and ACTH levels. We defined SH in the presence of at least 2 out of: Se-DST>83 nmol/L, ACTH<10 pg/ml, UFC>193 nmol/24 h. In all patients, the presence of diabetes, hypertension and dyslipidemia was detected as an indirect marker of SH.

Results: MSC levels were higher in patients with SH (8.8±9.1 nmol/L) than in those without (4.5±3.3 nmol/L, p=0.03). CS8 and Sa-DST were comparable between patients with and without SH (22.9±23.2 vs 18.2±14.3 nmol/L, P=0.4; 6.6±7.2 vs 4.6±3.9 nmol/L, P=0.06; respectively). The CS8 and MSC levels were associated with Se-DST (R=0.4 and 0.5, respectively, P<0.01). The presence of chronic complications was related to Se-DST (R=0.3, P=0.03) but not to any salivary parameter. Using the MSC cut-off of 2.8 nmol/L the sensitivity (Se) and the specificity (Sp) for diagnosing SH was 25% and 81% respectively. MSC values <1.0 nmol/L excluded the presence of SH (Sp 38%), while MSC >8.0 nmol/L had the 100% Sp (Se 13%).

Conclusion: In AI patients, CS8 and Sa-DST are of limited utility, while MSC, even measured by LC-MS/MS, cannot be used for the SH screening, though may be useful as a confirmative test.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.