Nocturnal cortisol release during hypoglycemia in diabetes

Area of Science:

• Endocrinology
• Metabolic Disorders
• Diabetes Management

Background:

• Nocturnal hypoglycemia is a common complication for individuals with diabetes on insulin therapy.
• Clinical recognition of nocturnal hypoglycemia can be challenging.
• Overnight urinary cortisol excretion has been proposed as a potential biochemical marker.

Purpose of the Study:

• To evaluate the utility of the overnight urinary cortisol-creatinine ratio as a marker for nocturnal hypoglycemia in insulin-treated diabetic patients.
• To compare cortisol profiles and excretion in diabetic patients with and without nocturnal hypoglycemia.

Main Methods:

• Assessed plasma cortisol levels and overnight urinary cortisol-creatinine ratios in six diabetic patients experiencing nocturnal hypoglycemia (≤ 2.5 mmol/L).
• Compared these measurements with a normal control group and five diabetic subjects without nocturnal hypoglycemia.
• Monitored plasma cortisol, growth hormone, and glucagon during hypoglycemic episodes in one patient.

Main Results:

• Only one of six diabetic patients with nocturnal hypoglycemia showed an abnormal overnight urinary cortisol-creatinine ratio.
• Plasma cortisol levels and urinary cortisol excretion indices were similar between hypoglycemic diabetic patients and control groups in most cases.
• One patient had an elevated urinary cortisol-creatinine ratio but no corresponding increase in plasma cortisol, growth hormone, or glucagon during hypoglycemia.

Conclusions:

• The overnight urinary cortisol-creatinine index is not a reliable biochemical marker for detecting nocturnal hypoglycemia in insulin-treated diabetes.
• Current biochemical markers are insufficient for reliably identifying this clinical challenge.