Dr. E’s Case Study: The Case of the Fearful Boluser

Dr. E’s Case Study: The Case of the Fearful Boluser

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Fear of hypoglycemia is a common challenge in type 1 diabetes management. For many, this fear can significantly impact daily decisions such as bolusing for meals, and lead to suboptimal blood glucose control. For many people, this fear can create a cycle of avoidance.

Jasmine’s story, detailed in the case study below, highlights how advanced diabetes technologies like the Dexcom G7 CGM and the Tandem Control-IQ insulin pump can provide a proactive approach for people struggling with various aspects of diabetes management.

This case is interesting to me because of my patient’s fear of hypoglycemia, and as a result she became a fearful boluser. Even on a hybrid closed-loop system, she did not enter her carbohydrates with meals, and if it were not for the Tandem Control-IQ algorithm, her control would have been much, much worse. The other issue I found interesting is how her pump settings (insulin sensitivity factor, the insulin-to-carb ratio, and the basal rate) could have been adjusted better to help her time in range, despite being a fearful boluser.

Meet the Patient: Jasmine

Jasmine is a 50-year-old woman with a 20-year history of type 1 diabetes. She uses a Dexcom G7 CGM and a Tandem Control-IQ insulin pump.

The Problem: Fear of Hypoglycemia

Long before she was on any pump, she had several severe hypoglycemic episodes and developed a fear of hypoglycemia. She became extremely fearful of bolusing before meals. As you can see from her Tandem Control-IQ download, her time in range is only 32% with 0% below target, and 68% above 180 mg/dL.

What’s interesting is when you look at how her insulin is given (below), 42% (or 13 units per day) is given as a basal infusion, and 44% (or 13.4 units) is given as an autocorrection by Tandem Control-IQ. Only 13% (or 4 units a day) on average are given when Jasmine enters carbs and the system gives her a bolus.

If you look at her data in more detail, you can see that on Wednesday, January 17th she does very well in the fasting state overnight, indicating that her basal rate and sensitivity factors are set correctly. But she eats three meals a day without entering carbs and giving herself a bolus.

The Tandem Control-IQ algorithm increases her basal rate – as shown by the red circle – and you can see from the white dots with the blue squares around them indicated by the arrow that Control-IQ is working very hard giving her over nine autocorrections per day on average. It keeps the post-meal blood sugars at bay despite her eating a meal without blousing on her own.

This pattern continues day after day.

The Solution

Because Jasmine is someone with a fear of hypoglycemia who is afraid to bolus, we decided to make her pump settings more aggressive:

• We improved her insulin sensitivity factor from 1:60 to 1:45, meaning the algorithm will give her more insulin to achieve her goal of 110 mg/dL

• We also changed her insulin-to-carb ratio to 1:15 (1 unit of insulin for every 15g of carbs) for when she does bolus. Her previous insulin-to-carb ratio was 1:20

We wanted to encourage her to really try to bolus, so we asked her to try to enter carbs with her biggest meal of the day as a starting point. When she sees the improvement in her postprandial blood sugars on her own, hopefully she’ll consider giving herself more boluses.

The Takeaway

The overall lesson here is that hybrid closed-loop systems like the Tandem Control-IQ are called hybrid closed-loop for a reason – you still have to enter boluses (by entering carbs) for meals. They have modulating basal rates (in this case the basal rates went up tremendously) but when the algorithm predicts that the basal rate is not enough to control the postprandial blood sugar, it will give an autocorrection bolus in addition. In this case, Control-IQ did a pretty good job, considering Jasmine was not blousing for meals at all, and she did not restrict her carbohydrates.

The key for this patient though will be to alleviate her fear of hypoglycemia, which may involve seeing a diabetes therapist like Dr. Bill Polonsky or Susan Guzman at the Behavioral Diabetes Institute.

Jasmine’s case serves as a powerful reminder of the complexities in type 1 diabetes management, where emotional barriers like fear of hypoglycemia can be just as impactful as physical ones. While hybrid closed-loop systems like the Tandem Control-IQ and Dexcom G7 CGM provide powerful tools to stabilize blood glucose levels, they still require active participation from the user to achieve optimal outcomes. Explore more about diabetes management strategies and the latest technologies by visiting our educational resources or joining one of our upcoming events.