Outcomes Research with our Registry  

Our mission at T1D Exchange is to improve the lives of people living with type 1 diabetes (T1D). A large part of how we accomplish this mission is through research.  

At T1D Exchange, our Outcomes Research team collaborates with leaders in the T1D space and with other internal experts to design studies to understand the preferences, experiences, and quality of life of people living with T1D in the T1D Exchange Registry and Online Community.  

If you are a part of the Registry, you’ve likely seen study opportunities pop up on your dashboard. You may have even participated in some of these studies! And you may have wondered, what happens after you participate? 

Here, we’ll highlight our collaboration with Vertex Pharmaceuticals on severe hypoglycemia and hypoglycemia unawareness with participants in the Registry, which was recently published in Diabetes Care: Severe Hypoglycemia and Impaired Awareness of Hypoglycemia Persist in People With Type 1 Diabetes Despite Use of Diabetes Technology: Results From a Cross-Sectional Survey. 

 

The risks of low blood glucose 

Hypoglycemia, or low blood glucose, is a common experience when living with T1D. According to JDRF, hypoglycemia usually occurs when there’s more circulating insulin in your body than it needs. Hypoglycemia can happen through an insulin dose miscalculation, delayed eating, during or after exercise, or for what seems like no reason at all. Regardless of its cause, a fast-acting carbohydrate source is the treatment. 

Mild and moderate hypoglycemia are very common in people with T1D. In the T1D Exchange Online Community, many people report having low glucose a few times a week. 

Severe hypoglycemia occurs when blood glucose levels fall very low – usually less than 54 mg/dL. A key characteristic of severe hypoglycemia is that when glucose values fall this low, a person with T1D often will need help from others to recover. This is because severe hypoglycemia can interfere with a person’s ability to function or think normally. People may become very confused, lose consciousness/pass out, or even have a seizure. Left untreated, severe hypoglycemia can be life-threatening.   

The best way to avoid hypoglycemia is to keep a close watch on your glucose levels and to be attuned to how your body is feeling. The goal is not necessarily to eliminate low glucose levels altogether, but to catch them early and treat them with fast-acting sugar when they happen. But, for some people, this is a nearly impossible task.  

 

The problem of hypoglycemia unawareness  

Hypoglycemia unawareness — also called impaired awareness of hypoglycemia — prevents a person from feeling early signs and symptoms of low blood glucose. For people with hypoglycemia unawareness, having no symptoms of mild-to-moderate low glucose means it is much more likely to progress to severe hypoglycemia.  

 

Improved diabetes tech can help – but how much? 

As diabetes technology advances, people with T1D can closely monitor their real-time glucose values with a continuous glucose monitor (CGM), more easily and accurately dose insulin with  automated insulin delivery (AID) systems, and keep a closer eye on their insulin use with devices like smart insulin pens. 

These advances have helped people living with T1D to achieve lower HbA1c levels and spend more time in a recommended target glucose range. But do these advances lead to fewer episodes of severe hypoglycemia in people with hypoglycemia unawareness in the real world? 

Severe Hypoglycemia and Impaired Awareness of Hypoglycemia Persist in People with T1D 

Study Overview  

In 2021, we recruited and enrolled over 2,000 adults with T1D from the Registry to understand three questions: 

  1. How many people are meeting recommended targets for HbA1c (< 7.0%)?
  2. How common is hypoglycemia in people using different combinations of diabetes technology?
  3. How common is impaired awareness of hypoglycemia in people using different combinations of diabetes technology?  

 

Summary of Results 

In the graphic abstract below, you’ll see an overview of the study findings. 

 

 

Like many of our Registry participants, this was a sample of individuals who used more advanced diabetes tech. Most participants in this study used CGM to monitor their glucose levels. Among CGM users, most also used an insulin pump, and many used automated features on their pumps.

Yet approximately 20% of participants reported they had experienced at least one episode of severe hypoglycemia in the past year, and over half of these individuals reported at least two separate episodes of severe hypoglycemia. 

When we examined severe hypoglycemia and impaired awareness of hypoglycemia by types of diabetes technology used, we also saw some differences.  

  • People who did not use CGM experienced at least one recent episode of severe hypoglycemia (~34%) more often than CGM users (~19%). 
  • Even among CGM users, having at least one recent episode of severe hypoglycemia was more common in those who used multiple daily injections (MDI) (23%) compared to those who used AID insulin pumps (~17%) and insulin pumps.   

Over 30% of participants also were classified as having hypoglycemia unawareness. Hypoglycemia unawareness was seen in:  

  • 33% of individuals who used CGM + a manual insulin pump  
  • 30% of individuals who used CGM + an automated pump 
  • 29% of individuals those who used CGM + MDI 

Conclusions and Implications: The ‘So What?’ Summary

The takeaway from this study is that severe hypoglycemia continues to be a common challenge in adults with T1D, even in a sample of people using advanced diabetes technology. Among those who used MDI, the experience of at least one episode of severe hypoglycemia within the previous 12 months was somewhat more common. 

In addition to experiencing severe hypoglycemia, nearly a third of individuals in our sample were classified as having impaired awareness of hypoglycemia. This finding shows the persistent risk of severe hypoglycemia even among people who are meeting recommended guidelines for HbA1c and are using advanced diabetes technologies. 

The authors maintain while this research shows current diabetes technology is helpful at meeting certain recommended targets, a high risk for severe hypoglycemia remains. Thus, more research and treatment advancements are needed to support at-risk individuals with T1D to help minimize this life-threatening complication.