Two landmark clinical trials have demonstrated that hybrid closed-loop insulin delivery systems provide significant glycemic benefits for pregnant women with type 1 diabetes, offering improved safety and potentially cost-effective care during this critical period.
CRISTAL Trial Shows Safety and Overnight Benefits
The CRISTAL trial, a randomized controlled study conducted in Belgium and the Netherlands, evaluated the MiniMed 780G advanced hybrid closed-loop system in 95 pregnant women with type 1 diabetes. Participants were randomly assigned to either the hybrid closed-loop system (46 women) or standard of care (49 women) and followed until hospital discharge after delivery.
While overall time in range during pregnancy was similar between groups, the MiniMed 780G demonstrated significant safety advantages. Time below range with glucose less than 63 mg/dL was substantially lower in the hybrid closed-loop group compared to standard care (2.5% vs. 4.1%; P = .002). The system particularly excelled during overnight hours, with time in range from midnight to 6 a.m. significantly higher (75.1% vs. 67.2%; P = .0026) and overnight time below range dramatically reduced (1.9% vs. 4.2%; P = .0005).
"[The MiniMed 780G] provides some additional benefits: improved glycemic control overnight, less time in hypoglycemia [and] improved treatment satisfaction," said Katrien Benhalima, MD, PhD, associate professor and deputy head of the clinic in diabetes and endocrinology at UZ Leuven in Belgium.
Reduced Hospitalizations and Cost Benefits
Safety outcomes revealed no severe hypoglycemia hospitalizations among women using the MiniMed 780G, compared to five hospitalizations in the standard care group. The percentage of women who underwent cesarean section was lower in the hybrid closed-loop group (48.8% vs. 64.4%), and significantly fewer women experienced excessive gestational weight gain (32.6% vs. 56.5%).
An economic evaluation published in eClinicalMedicine found the hybrid closed-loop therapy may be cost-effective, with women using the MiniMed 780 spending approximately 232 fewer euros during pregnancy compared to standard care. "The higher cost of the 780G device is offset by the fact that women using the 780G pump had shorter and less frequent hospital admissions, mainly due to severe hypoglycemia and dysregulated diabetes, compared to the standard of care group," Benhalima explained.
Control-IQ Technology Shows Dramatic Improvements
A separate multicenter trial involving 91 pregnant women across 14 sites in Canada and Australia evaluated the Tandem t:slim X2 pump with Control-IQ Technology. This study showed even more pronounced benefits, with hybrid closed-loop therapy achieving significantly greater time in range for pregnancy (65.4% vs. 50.3%), representing a mean adjusted difference of +12.6 percentage points (95% CI, 9.9 to 15.2; P <.001).
The Control-IQ system users spent 11.4 percentage points less time above range and 1.04 percentage points less time below 63 mg/dL compared to standard care (both P < 0.001). The adjusted mean glucose was 11.2 mg/dL lower with hybrid closed-loop therapy (95% CI, 7.2 to 16.2; p < 0.001), correlating to an additional 3 hours more time in optimal range per day.
"Managing glucose levels during pregnancy with type 1 diabetes is of critical importance for optimal health in both mother and child," said lead investigator Lois Donovan, MD, clinical professor at the University of Calgary. "Our results reflect the importance of evolving automated insulin delivery to support those living with type 1 diabetes when they are pregnant or preparing for pregnancy."
Safety Profile Remains Favorable
Both trials demonstrated comparable safety profiles between hybrid closed-loop and standard care groups. The Control-IQ study reported one case of severe hypoglycemia in the hybrid closed-loop group and two cases of diabetic ketoacidosis in each arm. The CRISTAL trial found similar rates of severe hypoglycemia events between groups, with eight occurring in the hybrid closed-loop group and seven with standard care.
Delivery and Postpartum Benefits
Extended follow-up from the CRISTAL trial showed that hybrid closed-loop therapy maintained advantages during delivery, with women achieving higher time in range than those receiving standard care (71.5% vs. 63.1%; P = .03). "Many women really like that you can just continue with the closed-loop system throughout delivery," Benhalima noted.
These findings represent a significant advancement in diabetes care during pregnancy, addressing one of the most challenging aspects of type 1 diabetes management while potentially reducing healthcare costs through improved outcomes and reduced hospitalizations.
