A new study published in the Diabetes Technology and Therapeutics reveals that even with advanced hybrid closed-loop (HCL) insulin pump systems, adults with type 1 diabetes remain at risk of dangerous hypoglycemic episodes. The findings point to impaired awareness of hypoglycemia (IAH) and erratic glucose levels as major contributors to these events, challenging assumptions that technology alone can fully protect against severe lows.

Researchers surveyed 601 adult HCL users, analyzing their experiences over a six-month period. Participants provided information on severe hypoglycemia (SH) events, 30-day continuous glucose monitoring (CGM) data, hemoglobin A1c levels, and completed a validated hypoglycemia awareness questionnaire. The data showed that individuals with IAH and higher glucose variability were significantly more likely to experience SH and spend more time in level 2 hypoglycemia.

Interestingly, traditional CGM hypoglycemia metrics did not predict severe episodes, suggesting that standard glucose data may not always reflect real-life danger. Participants who experienced SH also tended to spend more time in hyperglycemia, especially above 250 mg/dL, and were more likely to have lower levels of education. However, age and diabetes duration had no significant link to hypoglycemia risk.

The subgroup that faced both SH and prolonged Lv2Hypo exposure showed the highest levels of glucose instability and the most profound IAH, emphasizing the compounded danger of these overlapping factors.