Hypoglycemia-prone adults benefit from suspend-before-low pump technology
medwireNews: People with type 1 diabetes at high hypoglycemia risk using insulin pumps have fewer hypoglycemic events if the pump is linked to a continuous glucose monitor and has a suspend-before-low feature, SMILE study data show.
Ohad Cohen (Medtronic International Trading Sàrl, Tolochenaz, Switzerland) and colleagues believe their findings “lend support to the wider adoption of this sensor-integrated pump technology in this high-risk population.”
The technology in question is the MiniMed 640G insulin pump system (Medtronic, Northridge, California, USA) that incorporates the SmartGuard suspend-before-low feature, which the researchers explain “suspends insulin delivery when the sensor glucose value is predicted to reach 20 mg/dL (1.1 mmol/L) above a preset lowglucose limit within 30 min.”
Cohen and team found that, during 6 months of use, the 76 individuals randomly assigned to treatment with a MiniMed 640G insulin pump system with continuous glucose monitoring (CGM) plus SmartGuard experienced an average of 1.1 sensor hypoglycemic events (≤55 mg/dL [3.1 mmol/L] for >20 min) per participant per week.
This was a significant 73% lower than the mean 4.1 hypoglycemic events per participant per week experienced among the control group of 77 people who were randomly assigned to receive the same pump but with masked CGM and they self-monitored their blood glucose.
All of the study participants were considered at high risk for hypoglycemia due to a recent severe hypoglycemic event or having hypoglycemia unawareness defined by a Clarke or Gold score of at least 4.
As reported in The Lancet Diabetes and Endocrinology, individuals in the intervention group also experienced significantly fewer severe hypoglycemic events, defined as those requiring third-party assistance with carbohydrate or glucagon administration, or other resuscitative actions, than those in the control group, at three versus 18.
Total daily insulin dose increased by 0.4 units in the intervention group and by 4.2 units in the control group, with no significant difference between the two groups. There was also no difference between the groups in the mean change in glycated hemoglobin (HbA1c), which fell by 0.16% and 0.25% from baseline in the intervention and control groups, respectively.
Cohen et al conclude that the results of their study, which is “the longest and largest” of its type to date “show that use of the system is safe and results in significant reductions in the number of sensor hypoglycaemic events and severe hypoglycaemia, compared with a CSII [continuous subcutaneous insulin infusion] control.”
However, they acknowledge that an important limitation in the SMILE design was the lack of a comparator group receiving CSII plus real-time CGM as this was not the current standard-of-care at the time.
In an accompanying comment, Norbert Hermanns, from the Research Institute Diabetes Academy Mergentheim (FIDAM) in Germany, and colleagues say: “Surprisingly, SMILE is only the fourth study showing the beneficial effects of CGM-based technology in people with diabetes who are prone to hypoglycaemia.”
They add that all of the studies “showed a similar level of reduced exposure to low glucose values with CGM-based technology irrespective of the insulin delivery method,” therefore “head-to-head comparisons are needed to [provide] a clearer distinction of effects attributable to the glucose monitoring method [versus those attributable to] the insulin delivery method.”
By Laura Cowen
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