Camilla Levister on the Nuances of Designing a Pregnancy-Specific Artificial Pancreas System for T1D

A consortium of 4 institutions, including the Icahn School of Medicine at Mount Sinai, conducted a first-of-its-kind study of an artificial pancreas, or closed-loop, system designed to address the unique challenges associated with type 1 diabetes (T1D) during pregnancy. Camilla Levister, MS, ANP-C, CDCES, a nurse practitioner at the Icahn School of Medicine at Mount Sinai Hospital in New York, gives insight into the nuances of testing artificial pancreas systems in pregnant women and the potential benefits of using such systems to manage T1D in this population.

Transcript

Can you speak to the burden of T1D self-management during pregnancy and the challenges of conducting studies on closed-loop systems in this population?

Type 1 diabetes in and of itself has its day-to-day challenges in regard to managing blood glucose levels. With pregnancy and diabetes, you have different targets as opposed to if you are managing diabetes on its own outside of pregnancy. in pregnancy, the fasting goal for blood glucose for a woman who has type 1 diabetes is less than 90 [mg/dL], and 1 hour after eating, less than 140 [mg/dL]. In the general population with type 1 diabetes, the overall recommendation by the American Diabetes Association is a fasting glucose of 80 to 130 [mg/dL], for example. So that's a bit different than the fasting glucose of less than 90 [mg/dL] for someone who is pregnant. And put on top of that the stressors of being pregnant.

When a lot of us think of somebody being pregnant, we think of them kind of eating for 2 and having those cravings with, you know, ice cream and pickles or something like that. And with type 1 diabetes, you really have to keep in mind, “How are all these different choices in terms of food, how are these going to impact my blood sugar levels? How is activity going to impact my blood sugar levels?” and trying to keep yourself from going too high, but also from having a lot of low blood sugars. And that can take a real toll aside from the overall stress of being pregnant, and then also having concerns about your own health, but then added on top of that the health of your baby. It's not just you that you're taking care of now—for the next 9 months or so, you're taking care of the child that's inside of you. Aside from that, then you've got also raising a child.

That whole time you really are looking at glucose levels. As a health care provider, we're helping to keep patients that are pregnant within these glucose targets that I mentioned. But even with somebody that's super motivated and doing all the things that are recommended, it still can be difficult to meet those targets. And that's why we have looked to technology to see if that can help with getting patients to those goals so they can have a healthy pregnancy. The American Diabetes Association has consensus guidelines for continuous glucose monitoring targets within pregnancy. Continuous glucose monitoring has become a big thing in pregnancy, and it's finally approved for pregnancy with the Dexcom G7 sensor. In the past and also during these trials, we used continuous glucose monitoring during our studies, but it had not yet been officially approved for pregnancy. And the concern wasn't that the sensor itself would necessarily do anything to the fetus. The concern was, because those blood glucose targets are so tight, you want to make sure that what you're looking at is actually representative of what's happening with the glucose—that it's accurate enough. So that was another thing that we also had to look at during these trials, as well.

Mount Sinai has been part of a consortium working on artificial pancreas technology for T1D during pregnancy. What have been some notable outcomes or findings?

Around 2019, some of the investigators from Mount Sinai that are involved in diabetes and pregnancy work got together with Mayo Clinic, Harvard, and Sansum Diabetes [Research Institute], to put together a consortium that would address the need of technology in pregnancy for women with type 1 diabetes. And their goal in doing that was to come up with a pregnancy-specific hybrid closed-loop insulin delivery system—basically, an artificial pancreas system that could meet those targets for pregnancy, those tighter glucose targets. Also, most importantly, would the outcomes be better than women that were not using this technology?

The initial part of the study was an observational study with this [National Institutes of Health] grant. And with that study, participants wore a Dexcom continuous glucose monitor and they used their own insulin pump system. They were using insulin pump systems that were not in closed-loop mode or artificial pancreas mode. So basically, it was just whatever settings that the provider had put in, that is what the patient was getting. If they wanted to adjust things, or the provider did, or they stopped insulin or suspended at certain times, then they did that. But it wasn't a dynamic hybrid closed-loop system that they were using. And of the 25 participants, about 7 of them reached that time-in-range target of at least 70%, between 63 and 140 mg/dL of glucose.¹ Then, when we did the interventional study using this pregnancy-specific hybrid closed-loop insulin delivery system, out of the 10 participants—and it was a very small trial, it was 10 participants—but of those 10, 9 of them were able to meet that target of over 70%,² which is huge. And it also can be something that may reduce the burden of pregnancy with type 1 diabetes. You already have enough responsibilities, as I mentioned, in terms of your day-to-day management with diabetes, but especially when you have yourself and someone else to also think of.

Reference

1. O'Malley G, Ozaslan B, Levy CJ, et al. Longitudinal observation of insulin use and glucose sensor metrics in pregnant women with type 1 diabetes using continuous glucose monitors and insulin pumps: the LOIS-P study. Diabetes Technol Ther. 2021;23(12):807-817. doi:10.1089/dia.2021.0112

2. Levy CJ, Kudva YC, Ozaslan B, et al. At-home use of a pregnancy-specific zone-MPC closed-loop system for pregnancies complicated by type 1 diabetes: a single-arm, observational multicenter study. Diabetes Care. 2023;46(7):1425-1431. doi:10.2337/dc23-0173