Purpose
Studies have suggested improved metabolic profiles in patients with adrenal insufficiency treated with dual-release hydrocortisone (DR-HC) compared with conventional hydrocortisone (C-HC). This study investigates the effect of DR-HC compared with C-HC treatment on five health variables: diurnal salivary cortisol/cortisone, body composition, bone health, glucose metabolism, lipids, and blood pressure.

Methods
Prospective study of 27 participants (24 men) with secondary adrenal insufficiency with measurements during stable C-HC and 16 weeks after treatment switch to DR-HC.

Outcomes
Diurnal salivary-cortisol/cortisone, body composition assessed by Dual-Energy X-ray absorptiometry scan, bone status indices (serum type I N-terminal procollagen [PINP], collagen type I cross-linked C-telopeptide [CTX], osteocalcin, receptor activator kappa-B [RANK] ligand, osteoprotegerin, and sclerostin), lipids, haemoglobin A1c (HbA1c), and 24-hour blood pressure.

Results
After the switch to DR-HC, the diurnal salivary-cortisol area under the curve (AUC) decreased non-significantly (mean difference: −55.9 nmol/L/day, P = 0.06). The salivary-cortisone-AUC was unchanged. Late-evening salivary-cortisol and cortisone were lower (−1.6 and −1.7 nmol/L, P = 0.002 and 0.004). Total and abdominal fat mass (−1.5 and −0.5 kg, P = 0.003 and 0.02), HbA1c (−1.2 mmol/mol, P = 0.02), and osteocalcin decreased (−7.0 µg/L, P = 0.03) whereas sclerostin increased (+41.1 pg/mL, P = 0.0001). The remaining bone status indices, lipids, and blood pressure were unchanged.

Conclusion
This study suggests that switching to DR-HC leads to lower late-evening cortisol/cortisone exposure and a more favourable metabolic profile and body composition. In contrast, decreased osteocalcin with increasing sclerostin might indicate a negative impact on bones.