Hypoglycaemia (revision 5)
Old revision·05:54, 22 Sep 2024·ListMakerLumi
| Hypoglycaemia | |
|---|---|
| Common threshold | Below 3.9 mmol/L (70 mg/dL) |
| Level 2 | Below 3.0 mmol/L (54 mg/dL) |
| Level 3 | Severe: requires assistance |
| Risk with incretin monotherapy | Low |
| Topic infobox · conventions | |
Hypoglycaemia is abnormally low blood glucose. It is classified by level: below 3.9 mmol/L as an alert value, below 3.0 mmol/L as clinically significant, and any episode requiring assistance as severe regardless of the measured value.[1]
Incretin agonists carry a low intrinsic risk because their action on insulin secretion is glucose-dependent: they amplify a response that glucose has initiated rather than initiating one. Below the glucose threshold for triggering, there is nothing to amplify.[2]
Risk arises when they are combined with agents that are not glucose-dependent — insulin and sulfonylureas — and the usual response on initiating an incretin agonist alongside either is to reduce the background agent.[1]
Why glucose dependence matters
[edit]The beta cell distinguishes a triggering signal from an amplifying one. Glucose metabolism raises the ATP:ADP ratio, closes potassium channels and admits calcium — the trigger. Incretin signalling raises cAMP, which increases the amount of insulin released per unit of calcium — the amplifier.[2]
Sulfonylureas act on the trigger, closing the potassium channel pharmacologically regardless of glucose, which is why they cause hypoglycaemia. Injected insulin bypasses the beta cell entirely.
This is a mechanistic argument rather than a guarantee. Reported hypoglycaemia rates on incretin monotherapy are low but not zero, and the residual reflects other contributors — missed meals, alcohol, renal impairment, and concurrent agents.[3]
References
- ^ a b American Diabetes Association. "Standards of Care in Diabetes." Diabetes Care 47(Suppl 1) (2024).
- ^ a b Nauck MA, Meier JJ. "The incretin effect in healthy individuals and those with type 2 diabetes." The Lancet Diabetes & Endocrinology 4(6):525–536 (2016). PMID 26876794.
- ^ Drucker DJ. "Mechanisms of action and therapeutic application of glucagon-like peptide-1." Cell Metabolism 27(4):740–756 (2018). PMID 29617641.