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Closed-loop insulin improves glucose control in pregnant women with type 1 diabetes

Pregnant women with type 1 diabetes achieved better glucose control with an overnight closed-loop intervention than with sensor-augmented pump therapy, according to data published in the New England Journal of Medicine.

“Pregnant women with type 1 diabetes face particular challenges in trying to maintain tight glycemic control,” Zoe A. Stewart, MD, of the Wellcome Trust-Medical Research Council Institute of Metabolic Science, at the University of Cambridge, England, and colleagues wrote. “Insulin requirements typically increase by a factor of 2 to 3 during the second and third trimesters, with substantial day-to-day variability, making the need for dose adjustments and their required magnitude unpredictable.”

To analyze the efficacy, safety and feasibility of an overnight closed-loop, or automated, insulin delivery among pregnant women with type 1 diabetes, the researchers conducted an open-label, randomized, crossover study comparing it with a sensor-augmented pump treatment. The researchers then followed up with a continuation phase using a day-and-night closed-loop system.

Sixteen pregnant women with type 1 diabetes completed 4 weeks of closed-loop pump therapy, in the intervention group, and sensor-augmented pump therapy, in the control group, in random order. In the continuation phase, 14 participants used the day-and-night closed-loop system until delivery. The primary outcome was the percentage of time that overnight glucose levels were within the target range of 63 to 140 mg per deciliter, or 3.5 to 7.8 mmol per liter.

According to the researchers, overnight glucose levels were in the target range 74.7% of the time during the close-loop intervention, compared with 59.5% during the control therapy (absolute difference, 15.2%; 95% CI, 6.1-24.2; P = .002). In addition, the overnight glucose level was 119 mg per deciliter, or 6.6 mmol per liter, during the closed-loop therapy, compared with 133 mg per deciliter, or 7.4 mmol per liter, during the control treatment (P = .009). There were no significant differences between the closed-loop and control therapies in the percentage of time in which glucose levels were below the target range, in insulin doses or in adverse event rates. During the continuation phase, glucose levels were in the target range 68.7% of the time, and the mean glucose level was 126 mg per deciliter, or 7 mmol per liter.

“Our crossover trial showed that overnight closed-loop therapy, as compared with sensor-augmented pump therapy, resulted in improved glucose control during pregnancy in women with type 1 diabetes,” Stewart and colleagues wrote. “In the continuation phase, women receiving day-and-night closed-loop therapy maintained glycemic control during a high percentage of the time in a period that encompassed antenatal hospital admission, labor and delivery.” – by Jason Laday

Disclosure: The researchers report no relevant financial disclosures.