Would You Restrict Carbs to Ease Diabetes Management? (ADA 2020)

Children and adolescents with type 1 diabetes are currently living at a time of a big diabetes technology boom. Continuous glucose monitors (CGMs) and insulin pumps are becoming more popular and offer the promise of better glycemic management and more freedom and peace of mind. As research and clinical trials on automated insulin delivery systems are in full-swing, clinicians from The Joslin Diabetes Center, Yale University, and Harvard University were interested in understanding various patient preferences. In one study, they posed the following question:

Would young people with type 1 diabetes be willing to limit their carbohydrate intake to a maximum of 50 g per meal if this meant they wouldn’t have to administer a manual bolus using an artificial pancreas (AP) system? 

The outcomes of this research were recently presented at the American Diabetes Association (ADA) 80th Scientific Sessions.

To help understand patient perspectives and preferences on this subject,  39 participants (average age 17 +/- 4.7 years) were recruited at two study centers. These patients had an average diabetes duration of 9.4 +/- 4.9 years and an average HbA1c of 8.4 +/- 1.1 %. Interviews were conducted with each participant and parents to gauge their views on the willingness to “limit carb intake to 50 g per meal/snack if this would eliminate the need to manually bolus for food when using the AP system.”

Based on their analysis, the study authors derived the following major insights:

  1. The majority of participants (and their parents) would prefer to have the option of eating more than 50 g per meal/snack and were willing to manually bolus for the excess carbs.
  2. Most believed that 50 g per meal or snack was too restrictive.
  3. Young people generally agreed that automation would “reduce self-care burden.”

The researchers concluded,

“An aversion to food restrictions overpowers the desire for an AP system that can independently manage glucose levels though limited carbohydrate intake. Carbohydrate limitations appear to increase self-care burden more than the time and effort expended on carb counting and bolusing. Future AP systems should consider options that enable users to choose to bolus manually for large meals and to forego bolusing for smaller ones.”

Here are a few notable quotes from the participants, which were highlighted in the poster presentation:

“I think that, if I had to choose between bolusing or limiting my carb intake, I think I would rather bolus, just because nobody really wants to be told what to do.” (25-year-old female)

“Every once in a while she wants to have an ice cream. You know, I think she should be allowed to have these things sometimes when she wants them. I don’t want her to be too restricted.” (Mother of a 16-year-old.)

Sadly, despite continuing advances in technology, the glycemic management for youth with type 1 diabetes has been stagnant or worsening, depending on the age group, for decades. As per the most recent available data, the average HbA1c for young people with type 1 is about 8.7%, similar to what was observed in this cohort. Automated insulin delivery could offer an important solution to so many young people who do not meet the ADA-set glycemic targets (currently, the organization recommends individualizing the A1c goals, from as low as <6.5% all the way up to <8% for some patients).

This study provides an interesting snapshot into what many young people with type 1 diabetes appear to consider very important — the freedom to eat whatever they want and bolus for it. 

There has been a long-standing debate, often in the diabetes online community, and sometimes among healthcare providers, about a low-carbohydrate approach for young people. Many have highlighted the benefits, and exceptional success stories. They are not just anecdotes, either. At least one study has demonstrated exceptional outcomes of carbohydrate lowering for youth with type 1 diabetes, with excellent adherence and reported quality of life, a normal average A1c of ~5.7%, and a very low rate of adverse events.

Nevertheless, some question difficulty of maintaining a lower-carbohydrate diet, and concerns have been cited over the potential for the development of eating disorders as a result of “restricted eating”.

When it comes to developing AP systems, this study suggests that many young patients would prefer more flexibility in the upper threshold of their carbohydrate intake and are willing to put in the work to manually bolus for and accept the outcomes, whatever they may be, of higher carbohydrate eating patterns, in lieu of sticking to a recommended carb limit and not having to manually deliver their insulin dose. Of  course, this is just a small study, and the results may be skewed towards this perspective due to the predominance of teenagers in this cohort. Also, it may be interesting to evaluate a shift in this perspective, if any, following a formal diabetes education program to explain to patients and parents, in detail, the benefits of lowering carbohydrate intake for diabetes management in general, and in the context of AP technology.

What are your thoughts on the subject? We love hearing from our readers.

Source: diabetesdaily.com

Debate: Should the Artificial Pancreas Include Glucagon? (ADA 2020)

For the millions of people living with type 1 diabetes worldwide, the development of an effective system to automatically regulate blood sugar levels is of paramount significance. Artificial pancreas systems (APS) are being developed with the goals of automatically adjusting the delivery of insulin (and potentially, glucagon) based on glucose readings from a continuous glucose monitor (CGM), taking a lot of burden off patients, improving glycemic management, and enhancing safety.

What is the best way to approach the design of an artificial pancreas system? What are the pros and cons of including glucagon in the system alongside insulin?

Two experts debated this important issue at the American Diabetes Association (ADA) 80th Scientific Sessions last month.

Dr. Roman Hovorka, PhD, FMedSci from the University of Cambridge, argued against the inclusion of glucagon in the system, while Dr. Steven J. Russell, MD, PhD from the Massachusetts General Hospital, presented his case to support the use of a dual-hormone system. Both speakers disclosed several relationships with diabetes technology companies (including those working to develop APS).

Here is the summary of this interesting debate.

The Case for Single Hormone

Dr. Roman Hovorka highlighted some research outcomes of artificial pancreas systems that utilize insulin alone.  He presented data from several studies showing that these devices “improve time in target and time below target” as well as reduce A1c. However, the time in target range was only increased by ~11%, and the A1c improvements were modest, with the average A1c still above the ADA recommendations.

Dr. Hovorka explained that the vast majority of companies are currently moving forward with single-hormone systems. He also focused on a system developed by Cambridge that he’s very familiar with, showing data where ~95% time-in-range (TIR) was achieved. Notably, he remarked that a low-carb diet was also an important factor in this success case. Overall, however, only 7% of users were shown to achieve a time-in-range metric of >90%, although 28% achieved a TIR of >80%, 69% achieved a TRI >70%, and 86% achieved a TIR of >60%.

The presenter noted that one of the main issues currently hindering the efficacy of the APS is the delayed insulin absorption and action after subcutaneous insulin delivery. Adding glucagon into the system will not fix the issue, he noted, as “dual hormone delivery DOES NOT accelerate insulin absorption.”

While he acknowledged that glucagon could be useful in reducing low blood sugar risk in such systems, he also highlighted the complexity and high cost of such a system as barriers. In addition, he noted that the use of two separate cannulas could be burdensome, and for children, in particular. He also noted that the chronic delivery of glucagon subcutaneously requires more research to identify any risks.

In comparing the outcomes between single-hormone vs. dual-hormone systems, Dr. Hovorka noted that there was a slight increase in the TIR for the dual system (~78% vs. 71% in the longest studies), and the mean glucose (156 mg/dL vs. 140 mg/dL) was lower for those using the dual system. He also presented data to indicate that daytime hypoglycemia (in particular during exercise) could be reduced using a glucagon-insulin system, while a single insulin system was enough to eliminate hypoglycemia overnight. Furthermore, “comparative benefits of the single- and dual-hormone systems for improving HbA1c and preventing severe hypoglycemia remain unknown,” he underscored.

The Case for Dual Hormone

Dr. Steven Russell noted first that he believes “insulin-only hybrid artificial pancreas systems are the state-of-the-art in diabetes care” and that he is involved with projects that utilize both single- and dual-hormone approaches. Next, he went on to explain why he thinks a dual-hormone system would be more appropriate.

After pointing out that there are actually two hormones that are missing in type 1 diabetes – insulin AND glucagon, he suggested that in addition to further preventing hypoglycemia, a dual-hormone system can also help achieve lower average glucose and higher TIR than an insulin-only system. He presented several studies to support this point, including recent data from his project.

Importantly, Dr. Russell pointed out that by using micro-doses of glucagon to prevent or treat hypoglycemia could “oppose weight gain or encourage loss”. This is because using glucagon instead of carbohydrates to prevent or treat low blood glucose “promotes satiety and increases energy expenditure”.

While the speaker acknowledged the challenges associated with developing a dual-hormone system, he also noted that recent work has been bringing us closer to achieving this feat effectively. For instance, a number of stable glucagon formulations are now available (although not yet FDA approved for use in such a system). The safety studies that have been conducted have been reassuring.

Moreover, Dr. Russell addressed a common concern of glycogen store depletion, citing a 2015 study that indicated “no significant decrement in liver glycogen after repeated glucagon doses”. Importantly, he also presented some research showing that “users prefer the bi-hormonal system”, especially among those who aim for lower targets.

When addressing the potential increase in cost for a dual-hormone system, Dr. Russell had this to say:

“[The] significant increase in beneficial outcomes will justify the increase in cost… The difference in having no automation to single-hormone artificial pancreas is the same increment as you get going from a single-hormone artificial pancreas to dual-hormone… If one can justify adding automation, one could justify some additional expense to add the cost of the glucagon…”


Numerous artificial pancreas systems are currently being developed, with the vast majority opting for the insulin-only version. No doubt, the specific algorithms and insulin types used also play a paramount role in their efficacy and patient satisfaction. The use of glucagon remains a point of contention.

What are your thoughts on the subject?

Source: diabetesdaily.com