medwireNews: The IN CONTROL trial demonstrates that continuous glucose monitoring (CGM) improves glycaemic control in Type 1 diabetes patients who have hypoglycaemia unawareness.
During 16 weeks of use, patients reduced the amount of time they spent in both hypoglycaemia and hyperglycaemia, the findings published in The Lancet Diabetes & Endocrinology show.
The trial involved 52 patients who spent 16 weeks using CGM and 16 weeks self-monitoring their blood glucose, in a randomly assigned order with a 12-week washout period between. The patients were all diagnosed with hypoglycaemia unawareness according to the Gold criteria.
The patients’ median sensor use during the CGM period was 89.4%, and this resulted in a significant 4.7 percentage point reduction in the time spent in hypoglycaemia (≤3.9 mmol/L), falling from 11.4% in the self-monitoring phase to 6.8%. The number of hypoglycaemic events per week fell from 11.1 to 10.1 and their duration per event declined from 98.5 to 60.7 minutes.
The largest difference was seen for the number of severe hypoglycaemic events per trial phase, which fell from 34 to 14.
Lead study author Cornelis van Beers (VU University Medical Center, Amsterdam, the Netherlands) and colleagues observe that the largest between-phase differences came with the lower/more severe definitions of hypoglycaemia.
This “might suggest that patients in our trial took action only when their glucose concentration was already 3.9 mmol/L or lower, or perhaps they defined a lower threshold for self-treating hypoglycaemia”, say the researchers.
But they add: “Importantly, CGM did reduce the frequency of hypoglycaemic episodes of less than 2·8 mmol/L, which can cause cognitive dysfunction as a result of neuroglycopenia.”
The team also stresses that there was no increase in glycated haemoglobin during the CGM phase of the study, “which is often the price paid when trying to avoid hypoglycaemia.”
Indeed, the proportion of time patients spent in hyperglycaemia (>10 mmol/L) significantly reduced with CGM, from 8.0% to 6.8%. Overall, this resulted in a 9.6 percentage point increase in the time spent in normoglycaemia, from 55.4% to 65.0%.
“These results support the use of CGM in this high-risk population”, say van Beers et al.
However, they note that the intervention did not result in improvements in patients’ hypoglycaemia awareness “possibly because CGM did not prevent all hypoglycaemia, but only reduced its duration and depth.”
They say: “More rigorous avoidance of hypoglycaemic events for a longer period of time might be needed to improve hypoglycaemia awareness.”
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