• Ariel Warren, RDN, CDCES

My FULL Review: Pros and Cons of Open-APS Looping Compared to Tandem and Medtronic




So I have been looping with Open-APS for a solid 10 months and I'm a fan. I was a bit hesitant to start looping because going this route uses Omnipod off-label. Therefore this system is not approved for therapeutic use and it is not FDA-Approved. Looping is also a highly experimental system. Meaning, that if anything were to go wrong while I am looping, I would be completely liable for the outcomes. So yes, big gulp here.


Although the idea of replacing a pump with a self-built app sounded scary, I'll be honest, after researching for months and also talking to other loopers who were also educators who had T1D, I was excited about trying something new that could make management easier and with fewer lows. How I see diabetes is a constant experiment. We, with beat-up pancreases, are constantly testing and experimenting in one way or another. Perhaps we are trying a different insulin, different settings (carb ratio, correction), trying new foods, adding exercise, adding exercise intensity, shoot, just achieving a low-free floor mopping session can feel like an experiment worth celebrating. The list goes on. We are living, breathing, and curious people who are always trying something new and getting a little wiser and more experienced with our diabetes each day.


My final push to start looping was when the Endocrinologist at the clinic where I work shared the A1c and Dexcom reports of a patient who recently started looping. The pt had a A1c in the mid-fives, her Dexcom graphs were so beautifully flat, and her standard deviation was around 20 mg/dL. The pt expressed that looping made her feel as though a huge burden had been lifted because she knew she had a system that could pick up the slack if she had an overaggressive basal or didn't hit her carb count just right.


As a Certified Diabetes Care & Education Specialist (CDCES) and a Registered Dietitian Nutritionist (RDN), I run a tight ship with my diabetes control. However, I'd be lying if I said it didn't take time to develop my habits, and that it doesn't take determination and consistency each day. I keep my A1c between 5.4-5.9%s (and that's without going low carb). But before looping, I felt that I was constantly tweaking and adjusting basal rates, carb ratios and correction factors. I even got sick of pumps all together and stuck with shots for a good 10 months. At the end of my pump-free break, I was ready to try something new and especially if that something that would allow for good control, less lows, and less work.


Being a Certified Pump Trainer with each of the major pump companies: Insulet (Omnipod), Tandem, and Medtronic, I am well-versed with pumps and spend a great deal of time working with patients to help them figure out which pump is the best fit for him/her. Knowing the ins and outs of each pump, I understand what sets each part apart from each other.


This post is not meant to go over every detail about looping. If you want more information, the best resource is the online loopdocs. However, the purpose of the post is to tell you about my top 5 favorite features while also briefly stating some of the most annoying drawbacks of Open-APS looping with the Omnipod (off-label).


I have more than 5 features, but after much thought, I have narrowed it down to the following.





My Top 5 Favorite Features of Open-APS Looping with Omnipod (off-label)



1. Predictable Blood Sugar Graph


There are four graphs used in the looping app: glucose, active insulin, insulin delivery, and active carbohydrates.




These graphs help the open-APS loop system predicate your blood sugar so it can either operate as an “open-loop” by making recommendations for you to approve or as a "closed-loop" by automatically setting the recommend basal rate.


What I love specifically about the glucose graph is that it gives you what your blood sugar is predicted to go over the next 6 hours according to how much insulin is on board, active carbs, type of absorption, also with your sensitivity settings in mind (carb ratio and correction factor). The more information you give your loop system, the more accurate this predicted blood sugar graph will be, and the more accurate this graph, the better your system can adjust your basal rate and keep your blood sugar within your target range.


2. Adjustable Blood Sugar Target Range


So far, this is the only hybrid closed loop system (HCL) that allows YOU to choose the target range that is best suited for your needs and goals. An HCL system related to an insulin pump simply means a system that adjusts your background basal. It's considered hybrid because it is only part of the whole system. If the system also bolused for meals and correction it would be a full system. The T-Slim X2 with Control IQ does have an automatic bolus feature, which is currently the only HCL that has an automatic bolus, however, it does not bolus for meals.


Being able to choose your own target range is HUGE! And wonderful. Like I previously mentioned, I like to run a tight ship with my blood sugar, so by having a system that allows for me to target a range of 85 - 110 mg/dL, allows me to better achieve my goals. I do not recommend this range for all, but because I know how I react to my foods and know how to manipulate settings as needed to keep in good control without increasing lows, this range works well for me. Keeping your blood sugar between 70 - 180 mg/dL, is a good place for most, and the ideal range for the people with diabetes is commonly suggested to be between 90 - 120 mg/dL.


With the Tslim X2 with CIQ, the "happy place" for the algorithm is between 112.5 - 160 mg/dL. When your blood sugar is predicted to go between 112.5 - 160 mg/dL within the next 30 min, the Tslim X2 pump will continue with your normal personal profile set basal.


For more about the Control IQ with Tandem, you can visit my full review about Tslim with Control IQ here.


With the 670G pump, the target blood glucose level is 120 mg/dL. However, the pump only corrects to 150 mg/dL, then uses the basal to gently bring you down to the 120 mg/dL. For those who love tight control, this system may cause anxiety for the increased wait times to get back to target.


However, the upcoming 780G will have a target blood sugar of 100 mg/dL, but this will be about a year or more before the release date. I will give more details about the details of this system in a later post, so stay tuned.


Being able to choose my own target blood glucose range with looping is wonderful, and I don't see an adjustable target range coming out soon through an FDA-approved pump in the near future. But each of these pumps is developing ways to greatly lessen the burden of diabetes while improving quality of life. We have come a long way since 1963 when the first insulin pump was invented. It was so large, it is was designed to be used as a backpack (see below).


bantinghouse, Written by. “Banting's Legacy: Insulin Innovations.”Banting House, 12 Aug. 2016, bantinghousenhsc.wordpress.com/2016/08/12/bantings-legacy-insulin-innovations/.


Most importantly, you can use the fanciest insulin pump available, and yet still have poor control. Just because you are using any HCL system doesn't guarantee good control, but it can help you get there with less work. Good control takes consistency, investment in decent nutrition, exercise, good sleep, and understanding your body. These aren't habits you have to be perfect with this very second but habits that you can develop over time. And if you need help, reach out and work with others or perhaps work with an educator to get the specialized care and the support that you need to reach your goals.


3. Knowing My Daily Insulin Delivery


I LOVE the Insulin Delivery Graph. With this graph, you are aware of exactly how much insulin you have used as you go about the day, and depending on the type of carb you entered (fast, medium, slow absorption) you are made aware of the predicted insulin to be used over the next 1-4 hours.


The top reason I love this graph is because of how much this graph increases accountability. I know that if I eat well, exercise, keep to my usual set amount of grams of carbs for the day, I can meet my insulin delivery amounts to reach my goal of less than 20U total for the whole day.


Being able to actively see my insulin delivery helps me stay accountable to my healthy habits such as daily exercise, good nutrition, and at least 7 hours of quality sleep. If I eat poorly , skip exercise, or don't sleep, I require more insulin and become more insulin resistant.


I know I'm a nerd, but this graph gamifies my goals and gives me feedback on my efforts. When I eat poorly or don't exercise, I have increased insulin resistance and overall insulin needs, and I see it in my total insulin delivery. On these days, I see a delivery amount between 25 - 30+ units for the total day, especially if it was a brownie baking day with my son or a popcorn night with my husband (sometimes both). I have these days about once a week and I enjoy them when they happen. I absolutely love a treat or some good popcorn over the weekend and it's all about moderation for a healthy mindset and sustainability.


You can get the total daily dose on other pumps, but other pumps do not have a graph that details your insulin delivery amount each hour of the day.


4. Choosing Food Types


This feature is likely my favorite of the five listed features and it is completely unique to looping. With this feature, you can choose the rate of absorption of the food you are eating: fast, medium, or slow. The reason this is such an awesome feature is that it helps the pump better predict the necessary insulin required to keep your blood sugar on point.


Choosing a slow versus a medium or fast absorption will change the type of bolus. For instance, a slow absorption bolus of 30 grams will take 4 hours, less of an initial bolus, and a higher extended bolus (default at 4 hours). While a fast absorption bolus of 30 grams will have a much higher initial bolus and far less if any of the insulin used over the extension (set at 2 hours).


Along with the feature, you can also manually choose the amount of time a food takes to be absorbed. The slow food bolus option is defaulted at 4 hours, but you can extend this time for longer. This can be especially helpful for people with delayed gastric emptying with gastroparesis or for the times you just need the extra insulin for some totally-worth-it extra cheesy pizza or buttered popcorn. Been there done that!!


Along with the food type feature, there is a graph labeled, "Active Carbs" which tells you how long a carb is in your system affecting your blood sugar (known as Carbs on Board or COB). This is especially helpful in determining the carb ratio. By simply pressing on the Active Carb graph, you will get a detailed history of the carbs bolused and how many carbs were actually absorbed. If the actual absorbed number is usually greater than the number bolused, then this is a good indicator that you either need to be more accurate about your carb-counting or you need to decrease your carb ratio to make it more aggressive.


Also, for those who have a total daily carb amount, if you select this graph, it will share with you the total number of carbs you have consumed that day. My goal is about 150 grams per day, but over the weekend, I'm happy if it's below 200 grams! :)




5. Using my phone and watch to bolus


This feature is wonderful. By having looping on my iPhone and iwatch, I can bolus by entering the amount and absorption rate of carb (fast, medium, slow), then for security, the phone scans my face to start the bolus. I can also use my watch, and by using the scroll nodule on the side, I can enter the total amount of carbs and register to the iwatch that I would like to bolus for the entered amount.


What I love about this is how inconspicuous this system is. I could be out eating with friends or at work, and simply look like I am writing a quick text, but instead be bolusing for my lunch. And by using my iphone that is connected to omnipod, I don't have a tube to worry about. Oh boy, do I love not having a tube. I used the Medtronic 530G for over a decade and thought a tube was just apart of life with diabetes, but now that I have been looping with Omnipod and my phone for this long, I feel a huge burden has been lifted. I don't have a tube to drag me down. I can exercise, sleep, and go about the daily routine without getting tangled. I LOVE being tubeless.


The Cons to Open-APS Looping



As with any system, there are cons. However, I'm still looping so that shows that the pros outweigh the cons for me. Below is my list of the most annoying parts of this system (to be real here).


1. Not FDA-Approved, Not Approved for Therapeutic Use.


By not being FDA-approved, you are 100% percent liable if something goes wrong due to the looping system. If you have a leaking Omnipod or a bad sensor, those are not the app's fault, but if you program the settings incorrectly for example with ineffective basals, too high of a max basal, or perhaps too tight and too low or a range when you first get started, you could cause highs and lows that are a result of the system. To avoid this, thoroughly research by reading through the loopdocs online, connecting with others, or working with an educator who knows about looping. Also, make sure to start slow, for instance, start with an open loop, and close the loop once you have dialed in your settings and feel more comfortable.


2. Hairy to build (takes a little tech-savviness and about 4 hours)


The instructions to build this app are all online the loopdocs, and they are laid out, step-by-step, however, it still will likely take you about 4 hours, maybe 2.5 if you have a programming background. Anybody who can read and follow instructions can build the app themselves, and you don't have to build the whole app in one night, but understand that it isn't something you can simply download from the app store. Also, you need to learn how to build it yourself (or someone in your family) so if you need an update (and you will), you can build the app again without too much hassle.


3. Requires Specific Compatible Components


There are people working on Android and a freestyle system, but the most supported looping system requires the following components:

  • iPhone (iPhone 7 or later)

  • Mac with Catalina or Mojave

  • RileyLink

  • Omnipod with Eros pods (classic system)


4. Carry a RileyLink around


It's wonderful that you don't have to lug around a big PDM that looks like it came from Back to the Future, but you do need to carry the Rileylink around. To keep it simple, a RileyLink is a little device that allows your pump and pod to talk to each other: a translator if you will and your pump and pod speak two different languages. By keeping a Rilylink nearby, you allow for your pump and pod to connect and loop so basal adjustments can be made continuously, day and night.


5. This system can be "Buggy"


Lastly, I would say the most annoying part is that it is not uncommon to have a bad connection that keeps you from having a closed system. This isn't terrible because when you don't have the loop working, the pump will then just work as a regular pump by using your pump's regular programmed settings (i.e. basals, correction factor, carb ratio, etc). However, it may keep you from being able to bolus. Also, a poor connection can be for many reasons, which can make a poor connection rather frustrating to troubleshoot.


And that's it! My top features of what I love about looping and the parts that I find annoying. However, at the end of the day, for my goals and level of control, Open-APS looping with Omnipod is currently my preferred choice. I think each of the pumps is great and that the final choice should be entirely based on you, your goals, your nutrition, your level of hands-on management.


Summary of my Looping-APS Review


this post is just to give you a glimpse into what it is like to use an Open-APS looping system: its purpose is to give you an idea of what the good and bad looks like while using the pump and to help you figure out what management style is best for you.


♥♥♥♥♥♥♥♥♥♥

As always, if you are struggling with your diabetes (newly diagnosed or a long-time veteran). Perhaps you need are at the end of your pump warranty, or have always used pens and are considering a pump. Maybe you need setting adjustments or want to learn how to make your own adjustments safely. Maybe you want insight on how your nutrition is affecting your insulin sensitivity and your control, or you want to work with an HCP who understands on a personal level what it feels like to have diabetes. Do not hesitate to write me an email or schedule with me for a consultation. I'm here to help you. I love helping people like you increase their control, understand your diabetes, and get your life back so you can be with the people you love and live the life you want.

Sincerely,

Ariel Warren, RDN, CD, CDCES

UT-ADCES Chair-Elect

Diabetes Care & Education Specialist

Type 1 Diabetes for the Newly Diagnosed


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