Closed-loop systems may improve inpatient glycemic control over subcutaneous insulin delivery
Inpatients with type 2 diabetes who received automated closed-loop delivery of insulin spent more time in the target blood glucose range than those who received insulin subcutaneously, with no difference in rates of hypoglycemia.
For noncritical care inpatients with type 2 diabetes who require insulin therapy, closed-loop delivery may lead to better glycemic control than subcutaneous delivery without increasing the risk of hypoglycemia, a recent trial found.
Researchers conducted a randomized, open-label trial on general wards of two tertiary care hospitals in the U.K. and Switzerland. They assigned 136 adults with type 2 diabetes to receive either fully automated closed-loop delivery (n=70) or conventional subcutaneous therapy (n=66). The primary endpoint was the percentage of time that the sensor glucose measurement was within the target range of 100 to 180 mg/dL (5.6 to 10.0 mmol/L) for up to 15 days or until discharge. Results were published online on June 25 by the New England Journal of Medicine.
In the closed-loop group, the mean (±SD) percentage of time glucose measurements were in the target range was 65.8% (±16.8%), compared to 41.5% (±16.9%) in the control group, a difference of 24.3 (±2.9) percentage points (95% CI, 18.6 to 30.0; P<0.001). The mean sensor glucose measurement was 154 mg/dL (8.5 mmol/L) in the closed-loop group, compared to 188 mg/dL (10.3 mmol/L) in the control group (P<0.001). Above-target glucose values occurred in 23.6% (±16.6%) of patients in the closed-loop group, compared to 49.5% (±22.8%) of those in the control group, a difference of 25.9 (±3.4) percentage points (95% CI, 19.2 to 32.7; P<0.001).
There was no significant difference between groups in the duration of hypoglycemia (defined as a blood glucose level <54 mg/dL or <3 mmol/L) or in the amount of insulin delivered (median dose, 44.4 U in the closed-loop group vs. 40.2 U in the control group). No patients had severe hypoglycemia or clinically significant hyperglycemia with ketonemia.
The study authors noted limitations, such as how glucose measurements were more available in the closed-loop group and that the mean follow-up period was significantly longer in the closed-loop group than in the control group (7.9±3.9 d vs. 6.4±4.0 d, respectively; P=0.03). They added that in the control group, any loss of connectivity between the sensor and the receiver device would not have been detected and could have contributed to the smaller amount of sensor glucose data.
The authors wrote that “further work is required to determine practical considerations, facilitate ease of use, and assess costs” of using the closed-loop system in clinical practice. “Before closed-loop systems can have widespread use, they may need to be integrated with electronic-record systems in hospitals and with training for health care professionals,” they said.