The American Diabetes Association has defined hypoglycaemia in diabetes as “all episodes of an abnormally low plasma glucose concentration that expose the individual to potential harm” – a definition that avoids linking hypoglycaemia to a specific number.
While acknowledging the variability of response to glucose levels, the IHSG also sees value in a numerical threshold for clinically and health-economically significant hypoglycaemia. After numerous discussions, IHSG members reached a consensus that a glucose level of 3.0 mmol/L (54 mg/dL) is sufficiently low to indicate serious, clinically important hypoglycaemia.
In clinical trials, 3.9 mmol/L (70 mg/dL) is often set as a threshold for hypoglycaemia. The IHSG views this figure as an “alert value” rather than an upper limit of hypoglycaemia, because it does not necessarily incur symptoms or long-term harm. As such, it may not be necessary to report it routinely in clinical trials.