Advances in Insulin Delivery Systems - Episode 4

Limitations of Injectable Insulin in Type 1 and Type 2 Diabetes

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Drs Diana Isaacs and Natalie Bellini discuss the limitations of injectable insulins in achieving time-in-range and glucose targets in type 1 and type 2 diabetes.

Natalie Bellini, DNP, FNP-BC: The hardest part, if I can get the basal set, is getting those post-meal spikes down. In every interaction with every patient, there is at least some discussion of post-meal spiking because most patients see it. You were right-on when you said, what were you doing 30 minutes before dinner? As a clinician, think about your life 30 minutes before you eat. You’re letting your dog out, you’re cooking your dinner, you and your spouse are discussing the bill that came today that you weren’t expecting. That’s a patient, and that’s their life, too. To say to them, “What I really need you to do is to take your insulin, decide what you’re going to eat, and then don’t eat any more or any less, and remember 30 minutes from now to do that” in order for us to get that spike to not happen so they actually see a flat line is very difficult, and it could be dangerous, even. I say to patients that we can do it when we know what breakfast is there and you’re at your home, but I wouldn’t do it before a meal out. You’re having this kind of “do it as often as you can.” How many times can we ask a patient to do 2 injections? If they’re not on a pump and I say, “Well, you don’t know what you’re eating, but treat the high and give a little bit because you know you’re going to eat something. Then, you can always fix it after.” I’ve asked them to inject twice in 1 meal, and there’s breakfast, lunch, and dinner; we’re at 3 injections, and we’ve multiplied it to 6 injections. Then, you’d like a mealtime snack before bed, and that is another injection. That’s a lot of demand in a chronic disease that we’re trying to fit into someone’s life. Post-meal spiking is one of our biggest challenges, even with automated insulin delivery.

Diana Isaacs, PharmD, BCPS, BCACP, BC-ADM, CDCES: It can be challenging, and I agree. Even the automated insulin delivery has helped because it will suspend insulin, or completely stop insulin if hypoglycemia is occurring, and it’ll increase insulin in the background, but the boluses have just still been a challenge. The thing is that everyone says that we have carb counting. If you’re a perfect carb counter, then you should be able to stay under 180 and maximize that time in range from 70 to 180, but it’s not true because there are so many other factors. Adam Brown describes 42 factors that impact glucose levels, like the time of the day, other stressors in their life, the outside temperature, and all of these other things that can contribute. The biggest contribution is probably the fat and the protein from the meals, which don’t have as much of an impact, and that is why we generally advise carb counting. They still do have an impact. If someone eats a really high-fat meal, we expect that several hours later that their glucose is going to be running higher from that fat. We know that even with perfect carb counting that it’s really challenging to get to those time-in-range targets. That’s probably one of the reasons that the goal for most people is 70%, because 70% time-in-range correlates very well with an [HbA1c level] of around 7%, which is the goal for most people. With our current insulins, it’s been hard to go beyond 70% safely without having too much hypoglycemia. For most people, we’re trying to aim for under 4% of the time below 70 with less than 1% below 54.

Transcript edited for clarity