In primary adrenal insufficiency, there is an increased risk of hypoglycaemia and dehydration. These risks have been little studied particularly during intermittent fasting. The present study aimed to assess these risks in a prospective study of 30 subjects with primary adrenal insufficiency. Patients will undergo a clinical examination, blood sampling and continuous glucose monitoring for fourteen days (one week of fasting and one week of non-fasting).

The risk of hypoglycaemia in primary adrenal insufficiency (PAI) is well known but has been only few studied. It is explained by cortisol insufficiency. Only a few publications concerned this subject. The risk of hypoglycaemia seems to be increased during acute decompensation, following cessation of treatment and during fasting or delayed food intake. So, this risk would be increased during intermittent fasting such as the Ramadan fast. A previous study carried out in the endocrinology department of La Rabta University Hospital involving 30 subjects with secondary adrenal insufficiency who were monitored by continuous glucose monitoring (CGM) for 24 hours showed three cases of hypoglycaemia during intermittent fasting and no hypoglycaemia outside fasting. Studies assessing the risks of intermittent fasting concerned subjects with secondary adrenal insufficiency. No study assessed the risks of intermittent fasting in PAI. Furthermore, given the mineralocorticoid deficiency in PAI, there is also a risk of dehydration and hypotension.

Aims of the study:

Overall objective: to assess the risks of intermittent fasting in subjects with primary adrenal insufficiency.

Specific objectives:

• To assess the frequency of hypoglycaemia in subjects with primary adrenal insufficiency during fasting and outside fasting.
• To assess the frequency of dehydration in subjects with primary adrenal insufficiency during fasting and outside fasting.
• To study the factors associated with hypoglycaemia and dehydration.

Methods :

Type of study: prospective, cross over, comparative study with subjects taken as their own controls.

A group of 15 patients will be studied during the week preceding the month of Ramadan (non fasting week) and the first week of Ramadan (fasting week). A group of 15 patients will be studied during the fourth week of Ramadan (fasting week) and the first week after Ramadan (non fasting week). The analysis will thus concern 210 fasted days and 210 non-fasted days.

The included patients will be examined on two occasions 14 days apart. Visit 1 will include a clinical examination, the setting up of the continuous glucose monitoring system, a fasting blood sampling and the delivery of monitoring sheets.

Clinical data:

• Demographic data: age, gender
• Data relating to PAI: age, aetiology, replacement therapy. Fasting history and course (number of days fasted, occurrence of complications).
• Quality of life and quality of sleep questionnaire.
• weight, height, waist circumference, supine and standing blood pressure, heart rate, presence of melanoderma, signs of dehydration.

The patient will be given dietary and hygiene advice on fasting and the treatment (gluco- and mineral-corticosteroids) will be adjusted if necessary, in accordance with the recommendations published in 2021 and 2022.

Biological data: urea, iono

During the study period (two weeks), patients will be asked to fill in a monitoring form which will include details of medication taken, waking and bedtimes, physical activity and the occurrence of any discomfort (asthenia, signs of hypoglycaemia, signs of arterial hypotension or other).

Patients will be monitored during the fasting period by one of the investigators by telephone in order to check compliance with the protocol and the possible occurrence of complications.

Criteria for breaking the fasting: occurrence of malaise during fasting, hypoglycaemia diagnosed by CGM, elevation of urea or hyperkalaemia.

Visit 2 : the patients will undergo a clinical examination including quality of life and quality of sleep questionnaires and a physical examination, fasting blood sampling, recovery of the continuous glucose monitoring system and monitoring sheets.

Diagnosis criteria:

• Hypoglycaemia is defined as interstitial glucose measured during CGM < 2.8mmol/l.
• Dehydration is defined by the presence of arterial hypotension (BP <9/6cmHg or orthostatic hypotension) or elevated plasma urea.

Inclusion Criteria:

• Primary adrenal insufficiency
• Disease duration of at least one year
• Substituted with hydrocortisone and fludrocortisone
• Wishing to fast during the month of Ramadan 2024

Exclusion Criteria:

• Diabetes mellitus
• Renal insufficiency
• Hepatic insufficiency
• Cardiac insufficiency
• Respiratory insufficiency
• Use of hypoglycaemic agents
• Use of diuretics
• Use of glucocorticoids other than those prescribed for replacement
• Poor control of the disease (asthenia, malaise, melanoderma, discontinuation of treatment, etc.)
• Pregnancy
• Breast-feeding.

Data can be shared upon reasonable request.

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