How effective and safe is a closed-loop insulin pump for patients with type 1 diabetes?

This study compared the effectiveness and safety of a closed-loop and sensor-augmented insulin pumps for patients with Type 1 diabetes (T1D). The authors found that the closed-loop device was more effective but had more side effects for these patients.

The main goal of treatment for T1D is to balance blood glucose (sugar) levels. Insulin therapy helps lower blood glucose levels. One way to administer insulin is through a pump. Insulin pumps are able to measure blood glucose levels and administer insulin accordingly. One type of pump comes with a sensor that measures blood glucose levels and notifies the patient when levels are too high or too low. Then, the patient can adjust the insulin dose that the pump delivers. 

A closed-loop pump continuously monitors glucose levels and automatically adjusts insulin doses as needed. This means that the patient does not need to adjust insulin levels manually. This makes insulin therapy easier and more convenient for patients. Whether the closed-loop pump is safer and more effective than conventional pumps for patients with T1D remains under investigation.

This study had 168 patients with T1D. 112 patients received a closed-loop insulin pump. 56 patients received a conventional sensor-based insulin pump (control group). All patients used the pump for 6 months. The target range for blood glucose levels was 70-180 mg/dL.

After 6 months, blood glucose levels decreased from 166 mg/dL to 156 mg/dL in the closed-loop group.  In the control group, blood glucose levels stayed between 169-170 mg/dL.

In the closed-loop group, patients had blood glucose levels within the target range 61% of the time, on average. After 6 months, this amount of time increased to 71%. In the control group, patients had blood glucose levels within the target range 59% of the time; this remained unchanged during the study.

Overall, the closed-loop group spent 10% less time (2.4 hours per day) above and 0.88% less time (13 minutes per day) below the target blood glucose level compared to the control group. HbA1c levels (average blood glucose over the past 3 months) significantly decreased by 0.33% in the closed-loop group compared to the control group. 

16 patients in the closed-loop group and 2 patients in the control group experienced side effects. The most common side effect was high blood glucose levels (13 patients vs. 2 patients). No serious side effects were reported. Only 1 patient in the closed-loop group experienced DKA, a life-threatening condition where blood glucose levels are dangerously high.

The authors concluded that the closed-loop pump was more effective than the sensor-based pump for patients with T1D. However, more patients experienced hyperglycemia with the closed-loop pump.

The closed-loop pump used in this study did not have features that newer pumps have. These features have been shown to reduce episodes of low blood glucose. More studies are needed to confirm these results.