Flash glucose monitoring for diagnosis and management of post bariatric hypoglycaemia

Carolina B. Lobato1; Marta Guimarães1,2; Sofia S. Pereira1; Tiago Morais1; Mário Nora1,2; Mariana P. Monteiro1.

1 Endocrine, Cardiovascular & Metabolic Research, Unit for Multidisciplinary Research in Biomedicine (UMIB), University of Porto, Porto, Portugal.

2  Department of General Surgery, Centro Hospitalar de Entre o Douro e Vouga, Santa Maria da Feira, Portugal.

Background: Post-bariatric hypoglycaemia (PBH) is a rare yet emerging clinical condition that lacks well-established diagnostic criteria or management guidelines. Our aim was to unravel the potential of using flash glucose monitoring in the clinical assessment and management of patients with presumed PBH, based on the preliminary results of its implementation at our bariatric centre.

Methods: Two patients (A and B) submitted to Roux-en-Y gastric bypass (RYGB) (A: 4.8; B: 4.0 years earlier) presented with presumed PBH. After a comprehensive workout to rule out other causes for hypoglycaemia, patients underwent flash glucose monitoring for fourteen days coupled with simultaneous symptoms and meal diary record. Targeted data analysis was then performed to retrieve objective measures of patients’ glucose profiles (namely median and interquartile range, mean absolute glucose change [MAG change] and low blood glucose index [LBGI]).

Results: Both patients presented a marked glucose variability (MAG change: A: 2.7; B: 3.0), with greater glucose excursions towards both hyper- and hypoglycaemia ranges leading to recurrent low glucose events. Moreover, despite this pattern was accentuated on weekend days, a reduction in the risk of low glucose (LBGI: A: 2.3; B: 5.2) along the evaluation period was noticeable.

Conclusions: Flash glucose monitoring data targeted analysis along with food and symptoms diary records allows to retrieve objective and clinically relevant data in patients with presumed PBH. Our protocol stands out as a simple and easily accessible diagnostic tool not only to evaluate the magnitude of the condition but also to enable patient empowerment by raising self-awareness over behaviours triggering glucose fluctuations towards improved PBH management.