Study Compares MiniMed 780G and MiniMed 670G Algorithms

This content originally appeared on diaTribe. Republished with permission.

By Albert Cai

A new study in adolescents and young adults with type 1 diabetes directly compared two automated insulin delivery algorithms. Medtronic’s newer Advanced Hybrid Closed Loop (built into the MiniMed 780G system) improved glucose management more than the MiniMed 670G, though both systems showed impressive increases in Time in Range for this population. Ultimately, the 670G gave users over an hour and a half more time in range each day, while the 780G gave wearers over two hours every day in range!

Two Medtronic automated insulin delivery algorithms, the Advanced Hybrid Closed Loop and the MiniMed 670G, were recently compared in a cross-over study, allowing 113 participants to use both algorithms. Results from the study were published in the medical journal The Lancet. Notably, the study tested this technology in adolescents and young adults with type 1 diabetes ­– a group for which diabetes management is notoriously challenging. View our resources for adolescents with diabetes here.

For an introduction to automated insulin delivery (AID), check out our piece on current and coming-soon AID systems in 2021.

What is the MiniMed 670G?

The MiniMed 670G is an AID system that has been available since spring 2017 – it was the first system ever to “close the loop.” The system includes the MiniMed 670G pump, the Guardian Sensor 3 continuous glucose monitor (CGM), and an automated insulin adjustment algorithm. The algorithm adjusts basal insulin delivery every five minutes based on CGM readings, and a target of 120 mg/dl.

What is Advanced Hybrid Closed Loop?

Advanced Hybrid Closed Loop (AHCL) is Medtronic’s next-generation AID algorithm. The AHCL algorithm is used in Medtronic’s MiniMed 780G system, which is currently available in at least twelve countries in Europe. While it is not yet available in the US, Medtronic hopes to launch the 780G in the US this spring. In addition to automatic basal rate adjustments, the AHCL algorithm can also deliver automatic correction boluses and has an adjustable glucose target that goes down to 100 mg/dl. This is big news because many people using closed loop do not want to target the higher 120 mg/dl, even as a safety measure. The 780G algorithm is designed to have fewer alarms and even simpler operation than the MiniMed 670G system.

What was the study?

The newly published FLAIR (Fuzzy Logic Automated Insulin Regulation) study was conducted over six months across seven diabetes centers (four in the US, two in Europe, and one in Israel). The study enrolled 113 adolescents and young adults (ages 14-29) with type 1 diabetes. The study sample is notable, because teens and young adults with type 1 diabetes have the highest average A1C levels of any age group.

At the beginning of the study, participants performed their usual diabetes management routine for two weeks to establish their baseline glucose levels. Half of the group was then randomly assigned to use the MiniMed 670G system, while the other half of the group used the same pump and CGM, but with the new AHCL algorithm. After three months – the halfway point of the study – the two groups “crossed over,” switching to the opposite technology.

What were the results?

Nearly every measure of glucose management favored the AHCL period over the MiniMed 670G:

  • Compared to baseline, participants reduced time spent above 180 mg/dl by 1.2 hours per day when using MiniMed 670G and 1.9 hours per day when using AHCL.
  • Time in Range (TIR, time between 70-180 mg/dl) improved from a baseline of 57% to 63% using Minimed 670G and to 67% using AHCL.
  • Time spent below 70 mg/dl fell 0.2% of the time. While those 28 minutes a day may not be statistically significant – and time in severe hypoglycemia, or below 54 mg/dl, did not increase from baseline when using either algorithm – many people with diabetes would benefit from that additional half hour in range.

The graph below shows the time spent in glucose ranges during baseline, MiniMed 670G, and AHCL periods. For both algorithms, the Time in Range increase from baseline was significant – use of either AID system led to at least 14 hours more each week spent in range. Nevertheless, we also point out, of course, that the group (again, the group that has the most challenges of any age group managing diabetes) still experienced a fair amount of time above 250 mg/dl. This is  another reason for healthcare professionals and people with diabetes to think about the “whole person” when considering diabetes management, and another reason why we always recommend Adam Brown’s Bright Spots and Landmines for ways to improve diabetes management in terms of food, exercise, mindset, and sleep – it includes many strategies for people, especially teens and young adults, to use each day.

AID comparison

Image source: diaTribe

  • The biggest Time in Range improvement came overnight (between midnight to 6am). During this six-hour overnight period, AHCL users spent an average of 4.4 hours in range (74% TIR), compared to 4.2 hours (70% TIR) for 670G, and 3.5 hours (58% TIR) during baseline. While the overnight Time in Range difference between AHCL and 670G may not seem large, it added up to nearly a 22-hour difference over the three-month the AHCL period.
  • With daytime numbers, the average AHCL user spent 63 more hours (about 2.6 days) in range than the average 670G user in each three-month study period.

The graph below shows daytime and nighttime differences in time spent in range (70-180 mg/dl), and the data is included in a table at the end of this article. Better sleep the night before can also make diabetes management more effective during the day.

Comparison

Image source: diaTribe

  • Using MiniMed 670G drove an average A1C improvement from 7.9% to 7.6%, while AHCL use improved A1C from 7.9% to 7.4%.

Both systems showed extremely positive results and were found to be safe for use in young people with type 1 diabetes. The AID algorithms led to dramatic increases in Time in Range in a population that stands to benefit – over the course of a year, adolescents and young adults could spend more than ten additional days in range. The direct comparison between these two AID algorithms is highly informative – we hope to see similar trials in the future.

Comparison

Image source: diaTribe

Source: diabetesdaily.com

One Year into DIY Looping

One year ago, I built a DIY hybrid-looping insulin pump, using my Dexcom G6 and Omnipod. For those who aren’t in the know, DIY “looping” is basically “hacking” your insulin pump with a single-board computer, such a Raspberry Pi or Riley Link, to make it communicate with an existing continuous glucose monitor (CGM) to make basal adjustments accordingly.

It’s important to note that this is NOT FDA approved, but the #WeAreNotWaiting community has been sharing information on how to build your own DIY looping insulin pump for years now, and I took the plunge in 2019.

In July I celebrated one full year on my looping system, and wanted to share my thoughts on 365 days of looping.

I Still Have Diabetes

I remember when I first set up my Riley Link and switched on “auto-mode.” I had this magical vision of never counting carbohydrates again, limitless runs without lows, and forgetting what the thirst of a high blood sugar felt like. Then I realized, just as quickly, that I still have diabetes.

Even though my Dexcom continuous glucose monitor (CGM) readings now communicate with my insulin pump and make basal adjustments accordingly, the “hybrid” part means that it doesn’t anticipate, nor account for, any carbohydrates eaten. I also need to tell my pump when I’m about to exercise, and for how long. Since the insulin pump does not operate on artificial intelligence (AI), it cannot anticipate what I’ll do next.

So yes, I still have lows on runs and I still have highs when I eat something that isn’t appropriately accounted for. I still have to count carbohydrates and no, I haven’t forgotten what the Death Valley-like thirst of a 350 mg/dL feels like, although it happens less frequently.

My HbA1c Isn’t That Much Lower

I have always been maniacal about tight diabetes control. My A1cs have hovered in the low 6s for the last 10 or so years. With Loop, I immediately thought that my control would be *perfect* and I would ride out the 4s and 5s into an eternal sunset. NOPE. My latest A1c was 5.9%, which I am rightly ecstatic about, but it’s less than 1% point lower than I was on MDI and a CGM.

The key difference is that my time in range has increased from around 30% to 75%, and the number of lows that I experience has gone down from around 3 per day to 3 per week. It’s easy to have a low HbA1c when you have highs and lots of lows to average it out- it’s much harder (and healthier!) to have a lower HbA1c with few lows. And plus, I just feel healthier. And that has made all the difference.

Dexcom graph by Christine Fallabel

It’s a Mental Vacation

Being a human pancreas 24/7/365 is not easy (why didn’t anyone tell us this at diagnosis?!). In addition to running a household and having a full-time job (and texting everyone back, and maintaining some semblance of a fitness routine, and trying to eat something green at every meal), being an organ all of the time is hard work.

More than anything, a year into looping has given me the mental break I didn’t know I needed. Sure, I still have to count carbohydrates, adjust for exercise, and dose for meals, but hours can go by where I don’t think about diabetes at all, and that never used to happen. My mental distress has gone way down, and I don’t experience diabetes burnout at nearly the frequency I used to. This also helps maintain my motivation to continue to take care of myself and my diabetes.

Dosing Is More Discreet

As I make my way through my 30s, this is less of an issue (if you have a problem with me dosing in public, the problem is you, not my diabetes), but looping has definitely made checking my blood sugar (read: checking my phone) and dosing (also read: checking my phone) way more discreet in public than manually testing my blood sugar and dosing used to be. It’s also more hygienic (I change my insulin pump with plenty of alcohol swabs every 3 days from the comfort of my home), and more convenient. This is perfect when I’m out at a crowded concert, or squeezed into a small table at a restaurant.

It can also cause issues. For instance, if I’m in a public place where cell phones aren’t allowed, sometimes it’s difficult to explain that my iPhone is actually durable medical equipment (DME) that I need to survive. Let’s just say there have been some teachable moments.

Loop app screenshot by Christine Fallabel

I Am Happier

When I was diagnosed with type 1 diabetes in June of 2000, my doctor told me that the cure was just 5 years away. I thought the cure was just around the corner, we all did. And learning that the “cure” is still out of sight, 15 years hence, has been a hard pill to swallow.

I’ve dealt with anxiety and the impending depression of only someone who has a chronic disease with no cause and no cure can experience, but having something like Loop feels like someone is finally on my side, looking out for me, and making things just a little bit easier when the load becomes too heavy of a burden to carry. I can go to sleep and know that my basal will immediately shut off if I start to go low overnight. I can relax if I’m digging into dinner at a friend’s house and I don’t know the exact carb count for a meal, knowing my basal will tick up to cover the difference.

Having a Loop feels a little bit like you have a certified diabetes educator (CDE) and best friend just sitting on your shoulder, making constant adjustments, never judging, and ensuring that you have a better go of it, a little bit of help when you need it. And that help has been life-changing. The cure may never have been 5 years out, but with Loop, I finally feel okay waiting just a little bit longer.

Do you DIY Loop? How has your experience been? Share this post and comment below; we would love to hear from you. Follow the #WeAreNotWaiting hashtag on Twitter to learn more about the DIY movement.

Source: diabetesdaily.com

Debate: Can Technology Eliminate Hypoglycemia? (ADA 2020)

Advances in diabetes technology have brought forth a lot of new and valuable tools to people living with diabetes. From continuous glucose monitors (CGMs), to insulin pumps, to integrated systems that can automatically adjust insulin delivery based on CGM reading to safeguard against hypoglycemia, diabetes tech is rapidly evolving. For all insulin users, low blood glucose is of particular concern; too much insulin on board can quickly result in an emergency situation, if not promptly addressed.

At the American Diabetes Association (ADA) 80th Scientific Sessions, experts debated the following important question:

Can technology alone solve the problem of hypoglycemia in diabetes?

Dr. Richard M Bergenstal, MD from the International Diabetes Center at Park Nicollet argued “for”, while Dr. Emma G. Wilmot, MD from the University Hospitals of Derby and Burton present her case “against” this notion. Here is the synopsis from this exciting debate. Notably, both presenters disclosed numerous relationships with technology companies and pharmaceutical companies.

Yes, Technology Alone Can Solve the Issue of Hypoglycemia

Dr. Bergenstal began by defining four specific “problems” of hypoglycemia:

  1. “Dangerous levels and ripple effects of hypoglycemia”—low blood glucose levels can cause mental turmoil and may prevent patients from striving for optimal glycemia
  2. Defining hypoglycemia
  3. Detecting hypoglycemia
  4. Preventing hypoglycemia

We have been pretty unsuccessful at preventing hypoglycemia; that is, until technology was introduced,” he stated.

Strikingly, the presenter mentioned that after over 20 years of improvements to the average a1C levels, they are now increasing across the board. Dr. Bergenstal attributed this largely to people’s fear of hypoglycemia. He also mentioned a recent paper that indicates that, sadly, we are also experiencing a “resurgence in diabetes-related complications.”

Next, the presenter addressed the importance of consistently defining hypoglycemia. He explained that the official definitions of hypoglycemia (as defined for clinical trials reporting) have been evolving in recent years, now often defined by levels.

Then, the speaker moved forward to discuss that CGM technology was critical to the most thorough detection of hypoglycemia, noting that self-monitoring of blood glucose (SMBG, or finger-sticks) did not present the whole picture of blood glucose trends, making it more likely that low blood glucose could go unnoticed. Moreover, he argued that the accuracy of today’s CGM devices are on par with many blood glucose meters.

As far as the capability of technology in preventing hypoglycemia, Dr. Bergestal presented data from a very large international study showing that CGM use resulted in a tremendous decrease in both hyperglycemia and hypoglycemia, across a large patient population, across the board. He also presented data from several other studies that demonstrated the benefits of CGM technology as related to the incidence of hypoglycemia.

Next, he also addressed the role of “smart insulin pumps” that communicate with CGMs in helping to further reduce hypoglycemia. Strikingly, the results from one study using an “automated basal/hybrid closed loop system (closed loop at all times with meal-time manual assist bolusing)” resulted in a 100% reduction in hypoglycemia. The presenter also showed some case reports that suggested more technology (CGM + Pump vs. CGM + MDI) may yield better glycemic management. Furthermore, he touched upon several other advancements, ranging from faster-acting insulin formulations on the market and in development to smart insulin pens, and their relevance in improving outcomes (see below).

Dr. Bergenstal had this to say in conclusion:

“Technology can address [all four problems of hypoglycemia]… We’re going now from just good clinical care, to really ethics and just morality, I think. This journal of HealthCare Ethics Committee Forum, they looked at and postulated that continuous glucose monitoring is really a matter of justice. I know that sounds a little extreme, but if it can do what I’m showing you it can do, and people are struggling every day, maybe they really do have a right to use this technology… I think we better rely on technology to prevent the highs and the lows of diabetes.”  

No, Technology Alone Cannot Solve the Issue of Hypoglycemia

Dr. Emma Wilmot began by sharing that she loves diabetes technology, and that it plays an important role in reducing hypoglycemia. “However, technology ALONE can solve the problem of hypoglycemia? If only it were that simple,” she stated.

The speaker went on to present data showing that despite CGM use, as many as 25% of users are still experiencing severe hypoglycemia. She argued that “structured education” in diabetes management plays a more central role in reducing hypoglycemia, pointing to numerous research studies showing significantly improved outcomes following a formal diabetes education program.

Moreover, Dr. Wilmot commented on the role of hypoglycemia unawareness, and how reducing the incidence of low blood glucose levels via educational programs, also helped to mitigate hypoglycemia unawareness, in turn likely reducing severe hypoglycemia even more.   In contrast, she stated that there is no research to show that technology use can help to mitigate hypoglycemia unawareness. Furthermore, the presenter discussed several studies that showed “no additional benefit” of technology use (CGM and/or insulin pumps).

Technology is not for all,” Dr. Wilmot noted, citing issues like various technical problems, alarm fatigue, and site skin reactions. Strikingly, according to data from T1 Exchange, “41% had stopped using CGM in the past year.” Similarly, she noted, “30% of youth discontinued the hybrid closed-loop system”. Access and affordability is another paramount issue, she noted.

Rebuttals

While Dr. Bergenstal remarked that he understood and appreciated the role of patient education programs, he noted in his rebuttal, that the glycemic outcomes are not optimal in these patient populations, stating he believes technology can give us better control, reducing both hypo- and hyperglycemia.

Dr. Wilmot concurred that the levels of glycemia currently being achieve are “nowhere near good enough” and also agreed that several established educational programs are now incorporating technology education as well. However, she maintained that technology alone was not the sole solution.

Dr. Bergestal concurred with this, but also stated that technology is “outpacing everything else we’ve thrown at hypoglycemia so far.”

Conclusions

While most will agree that technology use can help to reduce hypoglycemia, whether it can be altogether (or even mostly) overcome with technology use alone remains a point of debate. Undoubtedly, the role of education in diabetes management plays a pivotal role. There is no “set-it-and-forget-it” in diabetes management today, not quite yet, anyway, and certainly not across the board for patients. Perhaps, as smart technology evolves further and becomes more mainstream, it may eventually overtake patient education in importance when it comes to preventing adverse events.

What are your thoughts on this subject?

Source: diabetesdaily.com

New Research: Hybrid Closed-Loop System Outcomes (ADA 2020)

Technology is truly changing the lives of many people with diabetes across the world. Advancements continue in many areas, including the development and testing of various automated insulin delivery systems.

The MiniMed 670G insulin pump system is the first of it’s kind in providing automatic insulin delivery adjustments based on continuous glucose monitoring (CGM) data. Now, two recent research studies, the results of which were just presented this weekend at the American Diabetes Association (ADA) 80th Scientific Sessions, are highlighting the positive outcomes of the system for young and adults patients.

Outcomes in Adult Patients

Dr. Stephanie Kim, MD, MPH, from the University of San Francisco, CA, presented the results of a single-center research study in adult patients with type 1 diabetes. The researchers enrolled 52 patients (47% female, average age 46 +/-12 years, average diabetes duration of 27 +/- 15 years) utilizing the Medtronic 670G system and started “Automode” delivery of insulin between 2017 and 2019, in an effort to evaluate the impact of automatic delivery on glycemic outcomes.

The study subjects were stratified into two groups, depending on baseline blood glucose levels (defined as A1c level of higher than 7.6% or lower than or equal to 7.5%). The A1c levels were evaluated at baseline (before starting Automode) and again approximately 17 months after starting Automode.

The data revelated that while the A1c level did not change significantly in patients in the lower A1c cohort, there was improvement in the group with baseline A1c>7.6%. These patients improved their A1c, on average, from 8.3% to 7.8% using this system.

Outcomes in Youth

Dr. Goran Petrovski, MD, PhD, of Sidra Medicine in Qatar, reported on the results of an observational study of children and young adults with type 1 diabetes who used multiple daily insulin injections (MDI) and switched to the MiniMed 670G hybrid closed-loop system. A total of 42 patients (ages 7-18, mean age 12 years) were enrolled in the study.

Excitingly, the study outcomes demonstrated considerable improvements to the average A1c levels (8.4% at baseline to 6.7% at 3-months follow-up, and 6.9% at 6-months follow-up) after initiating the hybrid closed-loop system therapy. Also, the time-in-range (defined in this study as blood glucose levels between 70-180 mg/dL) improved considerably with the use of this technology. Notably, no instances of diabetic ketoacidosis (DKA) or severe hypoglycemia were reported. The authors declared no conflict of interest and concluded that “children and adolescents with T1D can successfully initiate the HCL system, achieve and maintain better glycemic control than previous MDI regimen.”

Petrovski et. al. (Presented at ADA 2020)

Conclusions

Technology that can help people with diabetes better manage their blood glucose levels continues to improve. Notably, while the glycemic improvement in youth who transitioned from MDI to the automated system were considerable, the improvements were much more modest in the study on adults using this system who switched to Automode. Altogether, the data highlight the potential of technology to improve outcomes, while also revealing that technology use (at least as it stands today) is generally not enough on its own, to achieve optimal results. Patient education regarding diet, exercise, and the numerous intricacies of dosing insulin remain central to optimizing outcomes.

Source: diabetesdaily.com

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