medwireNews: People with type 1 diabetes at increased risk for hypoglycemia can reduce their risk and improve their time spent in target glucose range using automated insulin delivery (AID), show findings from the iDCL Trial Research Group.
AID reduced the risk for hypoglycemia by more than half, compared with continuous glucose monitoring (CGM) and a pump, in individuals with poor hypoglycemia awareness and/or severe hypoglycemia in the preceding 6 months, report Eric Renard, from Montpellier University Hospital in France, and colleagues.
They therefore say in Diabetes Care that “AID is strongly recommended for this specific population.”
The randomized controlled trial performed for 12 weeks with an optional 12-week extension phase included 72 individuals (45% women) aged an average of 47.2 years with a mean type 1 diabetes duration of 27.9 years and an average pump use of 11.7 years. In all, 49 were assigned to receive AID and 23 to receive an insulin pump.
The researchers note that there were significantly more men in the pump group than the AID group, at 52% versus 30%, otherwise the two groups were well matched.
Poor hypoglycemia awareness was defined as a Clarke Hypoglycemia Perception Awareness scale score above 3, and people were considered to have severe hypoglycemia if they had blood glucose levels below 70 mg/dL (3.9 mmol/L) for 5% of the time during 2 weeks of CGM.
During the first 12 weeks of treatment, people receiving AID spent significantly less time with blood glucose levels below 70 mg/dL (3.9 mmol/L) than did those in the pump group, at 2.8% versus 6.8%, equating to a treatment difference in favor of AID of 3.7 percentage points.
The researchers note that this improvement was “rapid,” occurring when patients switched to AID and was then sustained.
In turn, people in the AID group relative to the pump group were in the target range of 70–180 mg/dL (3.9–10.0 mmol/L) for a significant 6.8% more of the time and spent a significant 5.3% less time above target range.
The average blood glucose level did not differ significantly between the two groups, at 147.9 mg/dL (8.2 mmol/L) in the AID group and 151.9 mg/dL (8.4 mmol/L) in the pump group. However, the superior reduction in time above range with AID contributed to “significantly lower variability of glucose levels,” in this group, the investigators report, reaching on average the coefficient of variation target of less than 36%, compared with 40.3% among those using a pump.
The investigators comment that the findings were sustained in all 49 patients receiving AID who elected to continue treatment for a further 12 weeks in the extension phase, with similar improvements among 16 individuals from the pump group who switched to AID in this phase.
Over the whole 24 weeks, there was an improvement in hypoglycemia awareness, with a gradual decline in the Clarke score. This decline was significantly greater by 0.71 points with AID than a pump, reaching an average 3.35 versus 3.24 points, respectively, from a baseline average of 4.41 points. While Renard et al doubt the clinical significance of this, as the average scores remained above 3.0 points, they note that the percentage of patients in the AID group with scores above 3.0 points fell from 88% at baseline to 53% after 24 weeks.
Despite the reduction in hypoglycemia, the team reports two episodes of severe hypoglycemia in the AID population, compared with none in the pump group. Both cases were related to correction of hypoglycemia with oral glucose that led to automated correction bolus insulin delivery and subsequently caused the hypoglycemic episodes. The authors therefore say that “correction of hypoglycemia must be cautious with this AID system.”
Other adverse events in the AID group included two cases of ketoacidosis and one case of hyperglycemia related to insulin-infusion set failures, which the investigators say “should be preventable by reinforcement education,” as well as two adverse events (esophagitis and liver carcinoma) unrelated to diabetes. There were no adverse events in the pump group.
Based on the findings, the study collaborators conclude: “AID should be considered a potentially effective treatment line in the strategy of care for people with [type 1 diabetes] at high risk for hypoglycemia, prior to considering islet or pancreas transplantation.”
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