Randomized Trial of Assisted Hybrid Closed-Loop Therapy versus Sensor-Augmented Pump Therapy in Pregnancy.

OBJECTIVE: Examine gestational safety, glycemic and health outcomes of a hybrid closed-loop (HCL) system without pregnancy-specific glucose targets.

RESEARCH DESIGN: This was a pilot feasibility investigator-initiated, two-site, single blind, randomized controlled trial of sensor-augmented pump therapy (SAPT) vs HCL therapy in type 1 diabetes pregnancies. Participants were enrolled in the first trimester, randomized at 14-18 weeks gestation, and used SAPT or HCL until 4-6 weeks post-partum. We compared continuous glucose monitoring (CGM) metrics, severe hypoglycemia (SH), diabetic ketoacidosis (DKA), adverse skin reactions, and pregnancy outcomes between groups.

RESULTS: Baseline characteristics were similar between groups (n=11 HCL, n=12 SAPT). There were no SH or DKA episodes after randomization. Time spent <54 mg/dL did not differ between groups. Time spent <63 mg/dL decreased in both groups, significantly in the HCL group (3.52% (1.29% standard error) 2nd trimester and 2.82% (1.29%) 3rd trimester vs 7.92% (1.29%) run-in phase, p<0.05 for both). Mean sensor glucose was lower with SAPT compared to HCL therapy in the 3rd trimester (119 mg/dL (4.16 mg/dL) SAPT vs 132 mg/dL (4.26 mg/dL) HCL, p<0.05). Third trimester time-in-range (63-140 mg/dL) increased with SAPT (68.2% (3.09%) vs 64.3% (3.09%) run-in phase, p<0.05). Gestational health outcomes did not differ between groups. The HCL group used assistive techniques, such as fake carbohydrate boluses and exiting HCL overnight.

CONCLUSIONS: CGM within group differences were seen for time <63 mg/dL favoring HCL therapy and time-in-range favoring SAPT (3rd trimester vs baseline). Safety and adverse pregnancy outcomes were similar between groups.