Endocrine Abstracts

Background: Clinical reactive hypoglycemic events are defined as the coexistence of plasma glucose <60 mg/dl and autonomic and/or neuroglycopenic symptoms occurring in fed conditions. The diagnosis is based on tests aiming to simulate the causative triggers (i.e. mixed meal test). In clinical practice, however, a high percentage of symptomatic patients results negative to such diagnostic approach, leading to the impression of an inadequate sensitivity of this diagnostic tool. Based on this background, aim of the present study was to evaluate the diagnostic value of continuous glucose monitoring (CGM) associated to standard mixed meal test in the diagnosis of reactive hypoglycemia.

Methods: Thirteen subjects referring to our Center for symptoms suggestive for hypoglycemia were included in this study. All these subjects underwent i) mixed meal test (MMT); ii) CGM for 5 days for the evaluation of plasma or interstitial glucose level, respectively. We considered as positive the presence of symptoms and low glucose concentrations (<60 mg/dl for MMT and <70 mg/dl for CGM).

Results: Mean plasma glucose and the glycemic nadir during MMT (79.9±9.6 and 55.3±15.3 mg/dl) were similar to those during CGM (92.2±11.2 and 53.9±7.6 mg/dl). Four patients were positive to both MMT and CGM while 9 patients were negative to MMT but positive to CGM. The sensibility of CGM turned out to be 44%, the specificity 100% and the predictive positive value 80%.

Conclusion: The present study supports that CGM could be a relevant adjunctive tool in the diagnosis of reactive hypoglycemia. In fact, CGM is likely to be a diagnostic tool able to detect hypoglycaemic events during real life that are not adequately triggered by a standard MMT.