Drivers of hypoglycaemia in anorexia nervosa: Clinical severity, BMI, and illness duration

Anorexia nervosa (AN) often persists for years, resulting in high morbidity and mortality. Hypoglycaemia, typically assessed from a single morning blood sample, is a critical severity indicator. Continuous glucose monitoring (CGM) provides more comprehensive information on glycaemic patterns. This study aimed to characterize glycaemia in patients with AN and identify its potential drivers among metabolic severity (current BMI), clinical severity (Eating Disorder Inventory-2 [EDI-2] score), and illness duration, in a real-world outpatient setting.

This cross-sectional study included female outpatients with restricting subtype AN. Participants underwent CGM for five days in their usual environment. Collected data comprised age, BMI, illness duration, EDI-2 score, and continuous glycaemic measurements. Glycaemic biomarkers (hypoglycaemic area under the curve [AUC], mean and minimum glycaemia, and coefficient of variation) were computed over 24-hour periods.

Three hundred and four female patients were monitored for a mean of 4.8 days. No significant correlations were observed between glycaemic biomarkers and BMI. Illness duration was significantly associated with mean and minimum glycaemia (r = 0.26 and 0.23, respectively, p < 0.001) and with hypoglycaemia AUC (r = -0.25, p < 0.001).

In female patients with restricting subtype AN, illness duration, rather than BMI, appears to significantly influence glycaemic profiles. This may reflect glycaemic adaptations, a hypothesis that warrants further investigation using CGM, a practical tool for exploring metabolic changes and their potential clinical significance in AN.