A new critique highlights the need for standardised reporting of low blood sugar events in trials of GLP-1 receptor agonists used alongside insulin in type 1 diabetes, warning that current safety data may be incomplete and misleading.
A new critique is urging diabetes researchers to take hypoglycaemia far more seriously in trials of GLP-1 receptor agonists used alongside insulin in type 1 diabetes, arguing that the safety picture is incomplete without a clearer accounting of low blood sugar events. The comment, published in Endocrinology, Diabetes & Metabolism, says the drugs may offer modest metabolic gains, but those benefits are difficult to judge properly if studies do not report when hypoglycaemia occurs, how often it happens and how severe it is.
That concern lands against a growing body of research that has portrayed GLP-1 receptor agonists as potentially useful add-on therapies in type 1 diabetes. A systematic review and meta-analysis published this year found improvements in HbA1c, body weight, blood pressure and cholesterol when the drugs were added to insulin, although the average reduction in HbA1c was small. Separate reviews in 2025 and 2023 also reported modest glycaemic and weight benefits without a clear rise in severe hypoglycaemia, but both pointed to gastrointestinal side effects, especially nausea and vomiting, as a common reason for stopping treatment early.
The latest critique argues that those findings may be too reassuring if low-glucose events are not measured and reported in a standard way. In type 1 diabetes, where people depend on insulin to survive, the balance between better average glucose and more unstable day-to-day control can be especially delicate. The authors say a treatment may lower HbA1c while still increasing the risk of troublesome glucose swings unless researchers distinguish mild episodes from clinically dangerous ones.
Their warning is echoed by earlier trial evidence. In the ADJUNCT ONE study, liraglutide given with insulin was linked to more symptomatic hypoglycaemia at the 1.8 mg dose than placebo, and investigators also reported more hyperglycaemia with ketosis. A similar pattern appeared in ADJUNCT TWO, where symptomatic hypoglycaemia was more frequent with liraglutide 1.2 mg than with placebo. Those results do not by themselves prove a broad class-wide danger, but they do show why the details of reporting matter: average event rates can hide when episodes happen, whether they are nocturnal, and whether they are severe enough to need help.
The biological rationale is straightforward. GLP-1 receptor agonists can slow gastric emptying, reduce appetite and suppress glucagon after meals. In people with type 1 diabetes, whose insulin comes from injections or pumps rather than the pancreas, those effects can change the timing of food absorption and insulin action in ways that make low blood sugar more likely unless doses are adjusted carefully. The critique says future reviews should use standard definitions of hypoglycaemia, including the three-level classification endorsed by diabetes groups and regulators, so that studies can be compared more reliably.
The broader message is not that GLP-1 receptor agonists have no place in type 1 diabetes, but that their benefits should be judged alongside a transparent safety record. The authors say better reporting would help doctors decide which patients might benefit, how insulin should be adjusted and whether improvements in HbA1c reflect safer control or simply a trade-off with more glucose instability.
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
