Closed-Loop Insulin Delivery during Pregnancy in Women with Type 1 Diabetes

Abstract

BACKGROUNDIn patients with type 1 diabetes who are not pregnant, closed-loop (automated) insulin delivery can provide better glycemic control than sensor-augmented pump therapy, but data are lacking on the efficacy, safety, and feasibility of closed-loop therapy during pregnancy. METHODSWe performed an open-label, randomized, crossover study comparing overnight closed-loop therapy with sensor-augmented pump therapy, followed by a continuation phase in which the closed-loop system was used day and night. Sixteen pregnant women with type 1 diabetes completed 4 weeks of closed-loop pump therapy (intervention) and sensor-augmented pump therapy (control) in random order. During the continuation phase, 14 of the participants used the closed-loop system day and night until delivery. The primary outcome was the percentage of time that overnight glucose levels were within the target range (63 to 140 mg per deciliter [3.5 to 7.8 mmol per liter]). RESULTSThe percentage of time that overnight glucose levels were in the target range was higher during closed-loop therapy than during control therapy (74.7% vs. 59.5%; absolute difference, 15.2 percentage points; 95% confidence interval, 6.1 to 24.2; P = 0.002). The overnight mean glucose level was lower during closed-loop therapy than during control therapy (119 vs. 133 mg per deciliter [6.6 vs. 7.4 mmol per liter], P = 0.009). There were no significant differences between closed-loop and control therapy in the percentage of time in which glucose levels were below the target range (1.3% and 1.9%, respectively; P = 0.28), in insulin doses, or in adverseevent rates. During the continuation phase (up to 14.6 additional weeks, including antenatal hospitalizations, labor, and delivery), glucose levels were in the target range 68.7% of the time; the mean glucose level was 126 mg per deciliter (7.0 mmol per liter). No episodes of severe hypoglycemia requiring third-party assistance occurred during either phase. CONCLUSIONSOvernight closed-loop therapy resulted in better glucose control than sensor-augmented pump therapy in pregnant women with type 1 diabetes. Women receiving day-and-night closed-loop therapy maintained glycemic control during a high proportion of the time in a period that encompassed antenatal hospital admission, labor, and delivery.

Novel therapies for diabetes mellitus in pregnancy

“…After the initial eight week trial, 14 women continued to use the closed loop system for approximately 15 additional weeks, including time in labor and delivery. In these women, glucose concentrations were in the target range 68.7% of the time with a mean concentration of 126 mg/dL (7.0 mmol/L) 47. However, no clear benefit of closed loop therapy on adverse pregnancy outcomes was seen, as 13 of the 16 newborns in the study cohort had a birth weight greater than the 90th centile 47…”

“…Also, sensor augmented insulin pumps have been developed to integrate real time CGM and insulin pump technologies. A proof of principle crossover trial was performed in 16 pregnant women with type 1 diabetes 47. Women were randomly assigned for a four week period to using a CSII pump and a continuous glucose sensor with or without tablet computer software that automatically adjusted the pump basal insulin rate at night.…”

“…Women were randomly assigned for a four week period to using a CSII pump and a continuous glucose sensor with or without tablet computer software that automatically adjusted the pump basal insulin rate at night. After four weeks, they switched to the other treatment group 47. Closed loop therapy resulted in a higher percentage of time in the designated euglycemic range (63-140 mg/dL (3.5-7.8 mmol/L)) than control therapy (74.7% v 59.5%; 95% confidence interval for the difference 6.1 to 24.2; P=0.002), and the overnight mean glucose concentration was lower with closed loop therapy than control therapy (119 v 133 mg/dL (6.6 v 7.4 mmol/L); P=0.009) 47.…”

“…After four weeks, they switched to the other treatment group 47. Closed loop therapy resulted in a higher percentage of time in the designated euglycemic range (63-140 mg/dL (3.5-7.8 mmol/L)) than control therapy (74.7% v 59.5%; 95% confidence interval for the difference 6.1 to 24.2; P=0.002), and the overnight mean glucose concentration was lower with closed loop therapy than control therapy (119 v 133 mg/dL (6.6 v 7.4 mmol/L); P=0.009) 47. After the initial eight week trial, 14 women continued to use the closed loop system for approximately 15 additional weeks, including time in labor and delivery.…”

Closed-loop for type 1 diabetes – an introduction and appraisal for the generalist

“…Closed-loop use in children and adolescents has shown improvement in either time spent in the glucose target range [19] or reduction in hypoglycaemia risk [20]. In pregnant women with type 1 diabetes, improvements in time in the glucose target range and mean glucose was achieved by closed-loop without increasing hypoglycaemia risk compared to sensor-augmented pump therapy [21]. …”