Salivary cortisol levels during Ramadan fasting in hydrocortisone-treated secondary adrenal insufficiency patients

Patients with adrenal insufficiency have difficulties in fasting during the month of Ramadan with an increased risk of complications. Cortisol levels are unknown in these patients. The objective of this study was to assess the daily cortisol profile in hydrocortisone-treated patients with secondary adrenal insufficiency (SAI) and healthy controls during a fasting day. A cross-sectional matched case-control study on 50 hydrocortisone-treated SAI patients and 69 controls who are used to fast. Clinical and therapeutic data were collected. Five salivary samples for cortisol measurement were collected throughout a fasting day of the third week of Ramadan 2019. Salivary cortisol levels were significantly higher on awakening, at midnight and before the predawn meal in patients compared with controls. The circadian cortisol rhythm was disrupted in patients. The area under the salivary cortisol level versus time curve (AUC) was lower than the 2.5th percentile of the controls in one patient (2.5%) and higher than the 97.5th percentile in 23 patients (59%) who were considered overtreated. Age ≥ 35 years was independently associated with overtreatment (adjusted odds ratio = 12.0; 95% CI (2.0–70.4); p = 0.006). Seven patients broke their fasting for a complication compared with no one of the controls (p = 0.001). No factor was associated with this risk. Salivary cortisol levels were high in fasting hydrocortisone-treated SAI patients with a disruption of the circadian rhythm.