safety

What I wish CDEs (diabetes educators) and other HCPs knew about DIY and other diabetes tech (#OpenAPS or otherwise)

by Dana Lewis

I had the awesome opportunity to present at #AADE17, the annual education meeting for the American Association of Diabetes Educators, this past weekend. My topic was about OpenAPS and DIY diabetes… which really translates to some broader things I want all educators and HCPs to know about patients and technology, whether it’s DIY or just unknown to them. Unfortunately AADE didn’t record or livestream my session, so I wanted to write up a summary of the content here.

(If you’re new to this blog/me/OpenAPS, you can also watch this June 2017 TEDX talk where I share some of the story of how I ended up with a DIY artificial pancreas and how the OpenAPS community came to be; or this older talk from OSCON 2016 as well. As always, if you’re curious to learn more about OpenAPS or wondering how to build your own DIY artificial pancreas, OpenAPS.org is the first place to learn more!)

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Diabetes is hard. Even if you are privileged to have access to insulin, education, and technology – it can still be so incredibly hard to get it right. And even if you do everything “right”, the outcomes will still vary. And after all, the devices themselves are not perfect, and we still have diabetes.

The lack of varying alarms and the unchangeable volume is what led me to create DIYPS (my open loop and louder alarm system), and the same frustration with lack of data access and visualization led John Costik, Lane Desborough, Ben West, and so many others to explore creating other DIY tools, such as Nightscout. And thanks to social media, we all didn’t have to create in a vacuum: we can share code (this is what open source means) and insight through social media, and build upon each other’s work. As a result, these collaborations, sharing, and iterative development is how OpenAPS, the open source artificial pancreas system movement, was created.

I tweet and talk and share frequently about how great it is having #OpenAPS in my life. Norovirus? No problem. Changes in sensitivity due to exercise? Not the biggie it used to be.

Showing flat overnight CGM graph representing sleep uninterupted by hypoglycemia thanks to OpenAPS

However, this technology is by no means a cure. It still requires work on the part of the person with diabetes. We still have to:

  • Change pump sites
  • Change CGM sensors
  • Calibrate regularly
  • Deal with bonked pump sites and sensors that fall out

And also, given the speed of insulin, most people are still going to engage with the system for some kind of meal bolus or announcement. This is why it’s called “hybrid” closed loop technology. (However, depending on the sophistication of the technology, you start to get to be able to choose what you want to optimize for and the behaviors you want to choose to do less of, which is great.)

In some cases, we humans know more than the technology: such as when a meal is going to happen/is coming, and when exercise is going to happen. So it’s nice to be able to interoperate your devices and be able to use your phone, watch, computer, etc. to be able to tell the system what to do differently (i.e. set higher targets in the case of activity, or lower targets to achieve “eating soon” mode , or in the case of waking up).

But in a LOT of cases, it’s tiring for the human to have to think about all the things. Such as whether a pump site is slowly dying and causing apparent insulin resistant. Or such as when you’re more sensitive 12-24 hours after exercise. Or during menstrual cycles. Or when sick. Or during a growth spurt. Or during jet lag. Or during a trip where you can’t find anything to eat. Etc. It’s a lot for us PWD’s to track, and this is where computers come in handy. Things like autosensitivity in OpenAPS to automatically detect changes in sensitivity and adjust the variables for calculations automatically; and autotune, to track the data of what’s actually happening and make recommendations for changing your underlying pump settings (ISF, carb ratio, and basal rates).

And how has this technology been developed by patients? Iteratively, as we figure out what’s possible. It’s not about boiling the ocean; it’s about approaching problems bit by bit as we have new tools to solve them, or new people with energy to think about the problem in different ways. It’s like thinking about getting a car – you wouldn’t expect the manufacturer to sell bits and pieces of the car frame, and you don’t really expect medical device manufacturers to sell bits and pieces of a pump or other device. However, patients are closest to the REAL problems in living with diabetes. Instead of a “car”, they’re looking for solutions for getting from point A to point B. And so in the car analogy, that means starting with a skateboard, scooter, or bike – and ending up with a car is great, but the car is not the point.

So no, any piece of technology isn’t going to be a cure or solve all problems or work perfectly for everyone. But that is true whether it’s DIY or a commercial tool: one size certainly does not fit all. And patients are individuals with their own lives and their own challenges with diabetes, with different motivations around what aspects of life with diabetes feel like friction and what they feel equipped to tackle and solve.

So, here’s some of what’s on my list for what I’d like CDE’s and other HCP’s to know as a result of the proliferation of technology around diabetes:

  • Yes, DIY tech is often off label. But that’s ok – it just means it’s off label; it doesn’t prevent you from listening to why patients are using it, what we think it’s doing for us, and it doesn’t prevent you from asking questions, learning more, or still advising patients.
  • Don’t make us switch providers by refusing to discuss it or listen to it, just because it’s new/different/you don’t understand it. (By the way: we don’t expect you to understand all possible technology! You can’t be experts on everything, but that doesn’t mean shunning what you don’t know.)
  • You get to take advantage of the opportunity when someone brings something new into the office – it’s probably the first of many times you’ll see it, and the first patient is often on the bleeding edge and deeply engaged and understands what they’re using, and open to sharing what they’ve learned to help you, so you can also help other patients!
  • You also get to take advantage of the open source community. It’s open, not just for patients to use, but for companies, and for CDEs and other HCPs as well. There are dozens if not hundreds of active people on Twitter, Facebook, blogs, forums, and more who are happy to answer questions and help give perspective and insight into why/how/what things are.
  • Don’t forget – many of the DIY tools provide data and insight that currently don’t exist in any traditional and/or commercially and/or FDA-approved tool. Take autotune for example – there’s nothing else out there that we know of that will tune basal rates, ISF, and carb ratio for people with pumps. And the ability of tools like Nightscout reports to show data from a patient’s disparate devices is also incredibly helpful for healthcare providers and educators to use to help patients.

And one final point specific to hybrid closed loop technology: this technology is going to solve a lot of problems and frustrations. But, it may mean that patients will shift the prioritization of other quality of life factors like ease of use over older, traditionally learned diabetes behaviors. This means things like precise carb counting may go by the wayside for general meal size estimations, because the technology yields similar outcomes. Being aware of this will be important for when CDE’s are working with patients; knowing what the patterns of behaviors are and knowing where a patient has shifted their choices will be helpful for identifying what behaviors can be adapted to yield different outcomes.

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I think the increase in technology (especially various types of closed loops, DIY and commercial) will yield MORE work for CDE’s and HCP’s, rather than less. This means it’s even more important for them to get up to speed on current and evolving technology – because it’s by no means going away. And the first wave of DIY’ers have a lot we can share and teach not just other patients, but also CDE’s. So again, many thanks to AADE for the opportunity to share some of this perspective at #AADE17, and thanks to everyone for the engagement during and after the session!

Unexpected side-effect of closed looping: Body re-calibrations

by Dana Lewis

It’s fascinating how bodies adapt to changing situations.

For those of us with diabetes: do you remember the first time you took insulin after diagnosis? For me, I had been fasting for ~18 hours (because I felt so bad, and hadn’t eaten anything since dinner the night before) and drinking water, and my BG was still somehow 550+ at the endo’s office.

Water did nothing for my unquenchable thirst, but that first shot of insulin first sure did.

I still remember the vivid feeling of it being an internal liquid hydration for my body, and everything feeling SO different when it started kicking in.

In case the BG of 550+, the A1c of 14+ (don’t remember exact number), and me feeling terrible for weeks wasn’t enough, that’s one of the things that really reinforced that I have diabetes and insulin is something my body desperately needs but wasn’t getting.

Over the last ~14+ years, I’ve had a handful of times that reinforced the feeling of being dependent on this life-saving drug, and the drastic difference I feel with and without it. Usually, it’s been times where a pump site ripped out, or I was sick and high and highly resistant, and then finally stopped being as resistant and my blood sugar started responding to insulin finally after hours of being really high, and I started dropping.

But I’ve had different ways to experience this feeling lately, as a result of having live with a DIY closed loop (OpenAPS) for 2+ years – and it hasn’t involved anything drastic as a HIGH BG or equipment failure. It’s a result of my body re-calibrating to the new norm of my body being able to spend more and more time close to 100% in range, in a much tighter and lower range than I ever thought possible (especially now true with some of the flexibility and freedom oref1 now offers).

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I originally had a brief fleeting thought about how BGs in the low 200s used to feel like the 300s did. Then, I realized that 180 felt “high”. One day, it was 160.

Then one day, my CGM said flat in 120s and I felt “high”. (I calibrated, and turned out that it was really 140). I’ve had several other days where I’d hit 140s and feel like I used to do in the mid-200s (slightly high, and annoying, but no major high symptoms like 300-400 would cause – just enough to feel it and be annoyed).

That was odd enough as a fleeting thought, but it was really odd to wake up one morning and without even looking at my watch or CGM to see what my BGs had been all night, know that I had been running high.

I further classified “really odd” as “completely crazy” when that “running high” meant floating around the 130-140 range, instead of down in the 90-110 range, which is where I probably spend 95% of my nights nowadays.

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Last night is what triggered this blog post, plus a recurring observation that because I have a DIY closed loop that does so well at handling the small, unknown variances that cause disturbances in BG levels without me having to do much work, that as result it is MUCH easier to pinpoint major influences, like my liver dumping glucose (either because of a low or because it’s ‘full up’ and needs to get rid of the excess).

In last night’s case, it was a major liver dump of glucose.

Here’s what happened:

Scott and I went on a long walk, with the plan to stop for dinner on the way home. BG started dropping as I was about half a mile out from the restaurant, but I’m stubborn 😀 and didn’t want to eat a fruit strip when I was about to sit down an eat a burger. So, my BG was dropping low when I actually ate. I expected my BG to flatten on its own, given the pause in activity, so I bolused fairly normally for my burger, and we walked the last .5 miles home.

However, I ended up not rising from the burger like I usually do, and started dropping again. It was quite a drop, and I realize my burger digestion was different because of the previous low, so I ended up eating some fruit to handle the second low. My body was unhappy at two lows, and so my liver decided to save the day by dumping a bunch of glucose to help bring my blood sugar up. Double rebound effect, then, from the liver dump and the fruit I had eaten. Oh well, that’s what a closed loop is for!

Instead of rebounding into the high 300s (which I would have expected pre-closed loop), I maxed out at 220. The closed loop did a good job of bolusing on the way up. However, because of how much glucose my liver dumped, I stayed higher longer. (Again, this probably sounds crazy to anyone not looping, as it would have sounded to me before I began looping). I sat around 180 for the first three hours of the night, and then dropped down to ~160 for most of the rest of the night, and ended up waking up around 130.

And boy, did I know I had been high all night. I felt (and still feel, hours later) like I used to years ago when I would wake up in the 300s (or higher).

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Visuals

recalibration_3 hourHmm, 3 hours doesn’t look so bad despite feeling it.

recalibration_6 hour6 hour view shows why I feel it.

recalibration_12 hour12 hours. Sheesh.

recalibration_24 hour24 hours shows you the full view of the double low and why my liver decided I needed some help. Thanks, liver, for still being able to help if I really needed it!

recalibrating_pebble view of renormalizing Settling back to normal below 120, hours later.

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There are SO many amazing things about DIY closed looping. Better A1c, better average BG, better time in range, less effort, less work, less worrying, more sleep, more time living your life.

One of the benefits, though, is this bit of double-edged sword: your body also re-calibrates to the new “normal”, and that means the occasional extreme BG excursion (even if not that extreme!) may give you a different range of symptoms than you used to experience.

This. Matters. (Why I continue to work on #OpenAPS, for myself and for others)

by Dana Lewis

If you give a mouse a cookie or give a patient their data, great things will happen.

First, it was louder CGM alarms and predictive alerts (#DIYPS).

Next, it was a basic hybrid closed loop artificial pancreas that we open sourced so other people could build one if they wanted to (#OpenAPS, with the oref0 basic algorithm).

Then, it was all kinds of nifty lessons learned about timing insulin activity optimally (do eating soon mode around an hour before a meal) and how to use things like IFTTT integration to squash even the tiniest (like from 100mg/dL to 140mg/dL) predictable rises.

It was also things like displays, button, widgets on the devices of my choice – ranging from being able to “text” my pancreas, to a swipe and button tap on my phone, to a button press on my watch – not to mention tinier sized pancreases that fit in or clip easily to a pocket.

Then it was autosensitivity that enabled the system to adjust to my changing circumstances (like getting a norovirus), plus autotune to make sure my baseline pump settings were where they needed to be.

And now, it’s oref1 features that enable me to make different choices at every meal depending on the social situation and what I feel like doing, while still getting good outcomes. Actually, not good outcomes. GREAT outcomes.

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With oref0 and OpenAPS, I’d been getting good or really good outcomes for 2 years. But it wasn’t perfect – I wasn’t routinely getting 100% time in range with lower end of the range BG for a 24hour average. ~90% time in range was more common. (Note – this time in range is generally calculated with 80-160mg/dL. I could easily “get” higher time in range with an 80-180 mg/dL target, or a lot higher also with a 70-170mg/dL target, but 80-160mg/dL was what I was actually shooting for, so that’s what I calculate for me personally). I was fairly happy with my average BGs, but they could have been slightly better.

I wrote from a general perspective this week about being able to “choose one” thing to give up. And oref1 is a definite game changer for this.

  • It’s being able to put in a carb estimate and do a single, partial bolus, and see your BG go from 90 to peaking out at 130 mg/dL despite a large carb (and pure ballpark estimate) meal. And no later rise or drop, either.
  • It’s now seeing multiple days a week with 24 hour average BGs a full ~10 or so points lower than you’re used to regularly seeing – and multiple days in a week with full 100% time in range (for 80-160mg/dL), and otherwise being really darn close to 100% way more often than I’ve been before.

But I have to tell you – seeing is believing, even more than the numbers show.

I remember in the early days of #DIYPS and #OpenAPS, there were a lot of people saying “well, that’s you”. But it’s not just me. See Tim’s take on “changing the habits of a lifetime“. See Katie’s parent perspective on how much her interactions/interventions have lessened on a daily basis when testing SMB.

See this quote from Matthias, an early tester of oref1:

I was pretty happy with my 5.8% from a couple months of SMB, which has included the 2 worst months of eating habits in years.  It almost feels like a break from diabetes, even though I’m still checking hourly to make sure everything is connected and working etc and periodically glancing to see if I need to do anything.  So much of the burden of tight control has been lifted, and I can’t even do a decent job explaining the feeling to family.

And another note from Katie, who started testing SMB and oref1:

We used to battle 220s at this time of day (showing a picture flat at 109). Four basal rates in morning. Extra bolus while leaving house. Several text messages before second class of day would be over. Crazy amount of work [in the morning]. Now I just have to brush my teeth.

And this, too:

I don’t know if I’ve ever gone 24 hours without ANY mention of something that was because of diabetes to (my child).

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Ya’ll. This stuff matters. Diabetes is SO much more than the math – it’s the countless seconds that add up and subtract from our focus on school/work/life. And diabetes is taking away this time not just from a person with diabetes, but from our parents/spouses/siblings/children/loved ones. It’s a burden, it’s stressful…and everything we can do matters for improving quality of life. It brings me to tears every time someone posts about these types of transformative experiences, because it’s yet another reminder that this work makes a real difference in the real lives of real people. (And, it’s helpful for Scott to hear this type of feedback, too – since he doesn’t have diabetes himself, it’s powerful for him to see the impact of how his code contributions and the features we’re designing and building are making a difference not just to BG outcomes.)

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Thank you to everyone who keeps paying it forward to help others, and to all of you who share your stories and feedback to help and encourage us to keep making things better for everyone.

 

Choose One: What would you give up if you could? (With #OpenAPS, maybe you can – oref1 includes unannounced meals or “UAM”)

by Dana Lewis

What do you have to do today (related to daily insulin dosing for diabetes) that you’d like to give up if you could? Counting carbs? Bolusing? Or what about outcomes – what if you could give up going low after a meal? Or reduce the amount that you spike?

How many of these 5 things do you think are possible to achieve together?

  • No need to bolus
  • No need to count carbs
  • Medium/high carb meals
  • 80%+ time in range
  • no hypoglycemia

How many can you manage with your current therapy and tools of choice?  How many do you think will be possible with hybrid closed loop systems?  Please think about (and maybe even write down) your answers before reading further to get our perspective.

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With just pump and CGM, it’s possible to get good time in range with proper boluses, counting carbs, and eating relatively low-carb (or getting lucky/spending a lot of time learning how to time your insulin with regular meals).  Even with all that, some people still go low/have hypoglycemia.  So, let’s call that a 2 (out of 5) that can be achieved simultaneously.

With a first-generation hybrid closed loop system like the original OpenAPS oref0 algorithm, it’s possible to get good time in range overnight, but achieve that for meal times would still require bolusing properly and counting carbs.  But with the perfect night-time BGs, it’s possible to achieve no-hypoglycemia and 80% time in range with medium carb meals (and high-carb meals with Eating Soon mode etc.).  So, let’s call that a 3 (out of 5).

With some of the advanced features we added to OpenAPS with oref0 (like advanced meal assist or “AMA” as we call it), it became a lot easier to achieve a 3 with less bolusing and less need to precisely count carbs.  It also deals better with high-carb meals, and gives the user even more flexibility.  So, let’s call that a 3.5.

A few months ago, when we began discussing how to further improve daily outcomes, we also began to discuss the idea of how to better deal with unannounced meals. This means when someone eats and boluses, but doesn’t enter carbs. (Or in some cases: eats, doesn’t enter carbs, and doesn’t even bolus). How do we design to better help in that safety, all while sticking to our safety principles and dosing safely?

I came up with this idea of “floating carbs” as a way to design a solution for this behavior. Essentially, we’ve learned that if BG spikes at a certain rate, it’s often related to carbs. We observed that AMA can appropriately respond to such a rise, while not dosing extra insulin if BG is not rising.  Which prompted the question: what if we had a “floating” amount of carbs hanging out there, and it could be decayed and dosed upon with AMA if that rise in BG was detected? That led us to build in support for unannounced meals, or “UAM”. (But you’ll probably see us still talk about “floating carbs” some, too, because that was the original way we were thinking about solving the UAM problem.) This is where the suite of tools that make up oref1 came from.  In addition to UAM, we also introduced supermicroboluses, or SMB for short.  (For more background info about oref1 and SMB, read here.)

So with OpenAPS oref1 with SMB and floating carbs for UAM, we are finally at the point to achieve a solid 4 out of 5.  And not just a single set of 4, but any 4 of the 5 (except we’d prefer you don’t choose hypoglycemia, of course):

  • With a low-carb meal, no-hypoglycemia and 80+% time in range is achievable without bolusing or counting carbs (with just an Eating Soon mode that triggers SMB).
  • With a regular meal, the user can either bolus for it (triggering floating carb UAM with SMB) or enter a rough carb count / meal announcement (triggering Eating Now SMB) and achieve 80% time in range.
  • If the user chooses to eat a regular meal and not bolus or enter a carb count (just an Eating Soon mode), the BG results won’t be as good, but oref1 will still handle it gracefully and bring BG back down without causing any hypoglycemia or extended hyperglycemia.

That is huge progress, of course.  And we think that might be about as good as it’s possible to do with current-generation insulin-only pump therapy.  To do better, we’d either need an APS that can dose glucagon and be configured for tight targets, or much faster insulin.  The dual-hormone systems currently in development are targeting an average BG of 140, or an A1c of 6.5, which likely means >20% of time spent > 160mg/dL.  And to achieve that, they do require meal announcements of the small/medium/large variety, similar to what oref1 needs.  Fiasp is promising on the faster-insulin front, and might allow us to develop a future version of oref1 that could deal with completely unannounced and un-bolused meals, but it’s probably not fast enough to achieve 80% time in range on a high-carb diet without some sort of meal announcement or boluses.

But 4 out of 5 isn’t bad, especially when you get to pick which 4, and can pick differently for every meal.

Does that make OpenAPS a “real” artificial pancreas? Is it a hybrid closed loop artificial insulin delivery system? Do we care what it’s called? For Scott and me; the answer is no: instead of focusing on what it’s called, let’s focus on how different tools and techniques work, and what we can do to continue to improve them.

Being Shuttleworth Funded with a Flash Grant as an independent patient researcher

by Dana Lewis

Recently, I have been working on helping OpenAPS’ers collect our data and put it to good use in research (both by traditional researchers as well as using it to enable other fellow patient researchers or “citizen scientists). As a result, I have had the opportunity to work closely with Madeleine Ball at Open Humans. (Open Humans is the platform we use for the OpenAPS Data Commons.)

It’s been awesome to collaborate with Madeleine on many fronts. She’s proven herself really willing to listen to ideas and suggestions for things to change, to make it easier for both individuals to donate their data to research and for researchers who want to use the platform. And, despite me not having the same level of technical skills, she emits a deep respect for people of all experiences and perspectives. She’s also in general a really great person.

As someone who is (perhaps uniquely) utilizing the platform as both a data donor and as a data researcher, it has been fantastic to be able to work through the process of data donation, project creation, and project utilization from both perspectives. And, it’s been great to contribute ideas and make tools (like some of my scripts to download and unpack Open Humans data) that can then be used by other researchers on Open Humans.

Madeleine was also selected this year to be a Shuttleworth Fellow, applying “open” principles to change how we share and study human health data, plus exploring new, participant-centered approaches for health data sharing, research, and citizen science. Which means that everything she’s doing is in almost perfect sync with what we are doing in the OpenAPS and #WeAreNotWaiting communities.

What I didn’t know until this past week was that it also meant (as a Shuttleworth Fellow) that she was able to make nominations of individuals for a Shuttleworth Flash Grant, which is a grant made to a collection of social change agents, no strings attached, in support of their work.

I was astonished to receive an email from the Shuttleworth Foundation saying that I had been nominated by Madeleine for a $5,000 Flash Grant, which goes to individuals they would like to support/reward/encourage in their work for social good.

Shuttleworth Funded

I am so blown away by the Flash Grant itself – and the signal that this grant provides. This is the first (of hopefully many) organizations to recognize the importance of supporting independent patient researchers who are not affiliated with an institution, but rather with an online community. It’s incredibly meaningful for this research and work, which is centered around real needs of patients in the real world, to be funded, even to a small degree.

Many non-traditional researchers like me are unaffiliated with a traditional institution or organization. This means we do the research in our own time, funded solely by our own energy (and in some case resources). Time in of itself is a valuable contribution to research (think of the opportunity costs). However, it is also costly to distribute and disseminate ideas learned from patient-driven research to more traditional researchers. Even ignoring travel costs, most scientific conferences do not have a patient research access program, which means patients in some cases are asked to pay $400 (or more) per person for a single day pass to stand beside their poster if it is accepted for presentation at a conference. In some cases, patients have personal resources and determination and are willing to pay that cost. But not every patient is able to do that. (And to do it year over year as they continue to do new ground-breaking research each year – that adds up, too, especially when you factor in travel, lodging, and the opportunity cost of being away from a day job.)

So what will I use the Flash Grant for? Here’s so far what I’ve decided to put it toward:

#1 – I plan to use it to fund my & Scott’s travel costs this year to ADA’s Scientific Sessions, where our poster on Autotune & data from the #WeAreNotWaiting community will be presented. (I’m still hoping to convince ADA to create a patient researcher program vs. treating us like an individual walking in off the street; but if they again do not choose to do so, it will take $800 for Scott and I to stand with the poster during the poster session). Being at Scientific Sessions is incredibly valuable as researchers and developers, because we can have real-time conversations with traditional researchers who have not yet been introduced to some of our tools or the data collected and donated by the community. It’s one of the most valuable places for us to be in person in terms of facilitating new research partnerships, in addition to renewing and establishing relationships with device manufacturers who could (because our stuff is all open source MIT licensed) utilize our code and tools in commercial devices to more broadly reach people with diabetes.

#2 – Hardware parts. In order to best support the OpenAPS community, Scott and I have also been supporting and contributing to the development of open source hardware like the Explorer Board. Keeping in mind that each version of the board produced needs to be tested to see if the instructions related to OpenAPS need to change, we have been buying every iteration of Explorer Board so we can ensure compatibility and ease of use, which adds up. Having some of this grant funding go toward hardware supplies to support a multitude of setup options is nice!

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There are so many individuals who have contributed in various ways to OpenAPS and WeAreNotWaiting and the patient-driven research movements. I’m incredibly encouraged, with a new spurt of energy and motivation, after receiving this Flash Grant to continue to further build upon everyone’s work and to do as much as possible to support every person in our collective communities. Thank you again to Madeleine for the nomination, and to the Shuttleworth Foundation for the Flash Grant, for the financial and emotional support for our community!

Introducing oref1 and super-microboluses (SMB) (and what it means compared to oref0, the original #OpenAPS algorithm)

by Dana Lewis

For a while, I’ve been mentioning “next-generation” algorithms in passing when talking about some of the work that Scott and I have been doing as it relates to OpenAPS development. After we created autotune to help people (even non-loopers) tune underlying pump basal rates, ISF, and CSF, we revisited one of our regular threads of conversations about how it might be possible to further reduce the burden of life with diabetes with algorithm improvements related to meal-time insulin dosing.

This is why we first created meal-assist and then “advanced meal-assist” (AMA), because we learned that most people have trouble with estimating carbs and figuring out optimal timing of meal-related insulin dosing. AMA, if enabled and informed about the number of carbs, is a stronger aid for OpenAPS users who want extra help during and following mealtimes.

Since creating AMA, Scott and I had another idea of a way that we could do even more for meal-time outcomes. Given the time constraints and reality of currently available mealtime insulins (that peak in 60-90 minutes; they’re not instantaneous), we started talking about how to leverage the idea of a “super bolus” for closed loopers.

A super bolus is an approach you can take to give more insulin up front at a meal, beyond what the carb count would call for, by “borrowing” from basal insulin that would be delivered over the next few hours. By adding insulin to the bolus and then low temping for a few hours after that, it essentially “front shifts” some of the insulin activity.

Like a lot of things done manually, it’s hard to do safely and achieve optimal outcomes. But, like a lot of things, we’ve learned that by letting computers do more precise math than we humans are wont to do, OpenAPS can actually do really well with this concept.

Introducing oref1

Those of you who are familiar with the original OpenAPS reference design know that ONLY setting temporary basal rates was a big safety constraint. Why? Because it’s less of an issue if a temporary basal rate is issued over and over again; and if the system stops communicating, the temp basal eventually expires and resume normal pump activity. That was a core part of oref0. So to distinguish this new set of algorithm features that depart from that aspect of the oref0 approach, we are introducing it as “oref1”. Most OpenAPS users will only use oref0, like they have been doing. oref1 should only be enabled specifically by any advanced users who want to test or use these features.

The notable difference between the oref0 and oref1 algorithms is that, when enabled, oref1 makes use of small “supermicroboluses” (SMB) of insulin at mealtimes to more quickly (but safely) administer the insulin required to respond to blood sugar rises due to carb absorption.

Introducing SuperMicroBoluses (or “SMB”)

The microboluses administered by oref1 are called “super” because they use a miniature version of the “super bolus” technique described above.  They allow oref1 to safely dose mealtime insulin more rapidly, while at the same time setting a temp basal rate of zero of sufficient duration to ensure that BG levels will return to a safe range with no further action even if carb absorption slows suddenly (for example, due to post-meal activity or GI upset) or stops completely (for example due to an interrupted meal or a carb estimate that turns out to be too high). Where oref0 AMA might decide that 1 U of extra insulin is likely to be required, and will set a 2U/hr higher-than-normal temporary basal rate to deliver that insulin over 30 minutes, oref1 with SMB might deliver that same 1U of insulin as 0.4U, 0.3U, 0.2U, and 0.1U boluses, at 5 minute intervals, along with a 60 minute zero temp (from a normal basal of 1U/hr) in case the extra insulin proves unnecessary.

As with oref0, the oref1 algorithm continuously recalculates the insulin required every 5 minutes based on CGM data and previous dosing, which means that oref1 will continually issue new SMBs every 5 minutes, increasing or reducing their size as needed as long as CGM data indicates that blood glucose levels are rising (or not falling) relative to what would be expected from insulin alone.  If BG levels start falling, there is generally already a long zero temp basal running, which means that excess IOB is quickly reduced as needed, until BG levels stabilize and more insulin is warranted.

Safety constraints and safety design for SMB and oref1

Automatically administering boluses safely is of course the key challenge with such an algorithm, as we must find another way to avoid the issues highlighted in the oref0 design constraints.  In oref1, this is accomplished by using several new safety checks (as outlined here), and verifying all output, before the system can administer a SMB.

At the core of the oref1 SMB safety checks is the concept that OpenAPS must verify, via multiple redundant methods, that it knows about all insulin that has been delivered by the pump, and that the pump is not currently in the process of delivering a bolus, before it can safely do so.  In addition, it must calculate the length of zero temp required to eventually bring BG levels back in range even with no further carb absorption, set that temporary basal rate if needed, and verify that the correct temporary basal rate is running for the proper duration before administering a SMB.

To verify that it knows about all recent insulin dosing and that no bolus is currently being administered, oref1 first checks the pump’s reservoir level, then performs a full query of the pump’s treatment history, calculates the required insulin dose (noting the reservoir level the pump should be at when the dose is administered) and then checks the pump’s bolusing status and reservoir level again immediately before dosing.  These checks guard against dosing based on a stale recommendation that might otherwise be administered more than once, or the possibility that one OpenAPS rig might administer a bolus just as another rig is about to do so.  In addition, all SMBs are limited to 1/3 of the insulin known to be required based on current information, such that even in the race condition where two rigs nearly simultaneously issue boluses, no more than 2/3 of the required insulin is delivered, and future SMBs can be adjusted to ensure that oref1 never delivers more insulin than it can safely withhold via a zero temp basal.

In some situations, a lack of BG or intermittent pump communications can prevent SMBs from being delivered promptly.  In such cases, oref1 attempts to fall back to oref0 + AMA behavior and set an appropriate high temp basal.  However, if it is unable to do so, manual boluses are sometimes required to finish dosing for the recently consumed meal and prevent BG from rising too high.  As a result, oref1’s SMB features are only enabled as long as carb impact is still present: after a few hours (after carbs all decay), all such features are disabled, and oref1-enabled OpenAPS instances return to oref0 behavior while the user is asleep or otherwise not engaging with the system.

In addition to these safety status checks, the oref1 algorithm’s design helps ensure safety.  As already noted, setting a long-duration temporary basal rate of zero while super-microbolusing provides good protection against hypoglycemia, and very strong protection against severe hypoglycemia, by ensuring that insulin delivery is zero when BG levels start to drop, even if the OpenAPS rig loses communication with the pump, and that such a suspension is long enough to eventually bring BG levels back up to the target range, even if no manual corrective action is taken (for example, during sleep).  Because of these design features, oref1 may even represent an improvement over oref0 w/ AMA in terms of avoiding post-meal hypoglycemia.

In real world testing, oref1 has thus far proven at least as safe as oref0 w/ AMA with regard to hypoglycemia, and better able to prevent post-meal hyperglycemia when SMB is ongoing.

What does SMB “look” like?

Here is what SMB activity currently looks like when displayed on Nightscout, and my Pebble watch:

First oref1 SMB OpenAPS test by @DanaMLewisFirst oref1 SMB OpenAPS test as seen on @DanaMLewis pebble watch

How do features like this get developed and tested?

SMB, like any other advanced feature, goes through extensive testing. First, we talk about it. Then, it becomes written up in plain language as an issue for us to track discussion and development. Then we begin to develop the feature, and Scott and I test it on a spare pump and rig. When it gets to the point of being ready to test it in the real world, I test it during a time period when I can focus on observing and monitoring what it is doing. Throughout all of this, we continue to make tweaks and changes to improve what we’re developing. After several days (or for something this different, weeks) of Dana-testing, we then have a few other volunteers begin to test it on spare rigs. They follow the same process of monitoring it on spare rigs and giving feedback and helping us develop it before choosing to run it on a rig and a pump connected to their body. More feedback, discussion, and observation. Eventually, it gets to a point where it is ready to go to the “dev” branch of OpenAPS code, which is where this code is now heading. Several people will review the code and approve it to be added to the “dev” branch. We will then have others test the “dev” branch with this and any other features or code changes – both by people who want to enable this code feature, as well as people who don’t want this feature (to make sure we don’t break existing setups). Eventually, after numerous thumbs up from multiple members of the community who have helped us test different use cases, that code from the “dev” branch will be “approved” and will go to the “master” branch of code where it is available to a more typical user of OpenAPS.

However, not everyone automatically gets this code or will use it. People already running on the master branch won’t get this code or be able to use it until they update their rig. Even then, unless they were to specifically enable this feature (or any other advanced feature), they would not have this particular segment of code drive any of their rig’s behavior.

Where to find out more about oref1, SMB, etc.:

  • We have updated the OpenAPS Reference Design to reflect the differences between oref0 and the oref1 features.
  • OpenAPS documentation about oref1, which as of July 13, 2017 is now part of the master branch of oref0 code.
  • Ask questions! Like all things developed in the OpenAPS community, SMB and oref1-related features will evolve over time. We encourage you to hop into Gitter and ask questions about these features & whether they’re right for you (if you’re DIY closed looping).

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Special note of thanks to several people who have contributed to ongoing discussions about SMB, plus the very early testers who have been running this on spare rigs and pumps. Plus always, ongoing thanks to everyone who is contributing and has contributed to OpenAPS development!

Scuba diving, snorkeling, and swimming with diabetes (and #OpenAPS)

by Dana Lewis

tl;dr – yes, you can scuba dive with diabetes, snorkel with diabetes, and swim with diabetes! Here’s what you need to know.

I meant to write this post before I left for a two-week Hawaii trip, and since I answered about a question a day on various platforms as I posted pictures from the trip, I really wish I had done it ahead of time. Oh well. :) I especially wish someone had written this post for me 2 years ago, before my first scuba dive, because I couldn’t find a lot of good information on the practicalities of good approaches for dealing with all the details of scuba diving with diabetes and an insulin pump and CGM and now closed loops. Scuba diving, snorkeling, and swimming with diabetes are actually pretty common, so here are a few things to keep in mind/tips from me, before diving (pun intended) into some explanations of what I think about for each activity diabetes-wise.

scuba_diving_with_diabetes_tips_water_activities_by_Dana_M_Lewis

General tips for water activities when living with diabetes:

  1. Most important: be aware of your netIOB going into the activity. Positive netIOB plus activity of any kind = expedited low BG. This is the biggest thing I do to avoid lows while scuba diving or snorkeling – trying to time breakfast or the previous meal to be a few hours prior so I don’t have insulin peaking and accelerated by the activity when I’m out in the water and untethered from my usual devices.
  2. Second most important: CGM sensor and transmitter on your body can get wet (shower, pools, hot tubs, oceans, etc.), but keep in mind it can’t read underwater. And sometimes it gets waterlogged from short or long exposure to the water, so it may take a while to read even after you get it above water or dry off. And, historically I’ve had sensors come back and the CGM will sometimes read falsely high (100-200 points higher than actual BG), so exercise extreme caution and I highly recommend fingerstick testing before dosing insulin after prolonged water exposure.
  3. Know which of your devices are waterproof, watertight, etc. Tip: most pumps are not waterproof. Some are watertight*. The * is because with usual wear and tear and banging into things, small surface cracks start showing up and make your pump no longer even watertight, so even a light splash can kill it. Be aware of the state of your pump and protect it accordingly, especially if you have a limited edition super special super rare DIY-loopable pump. I generally take a baggie full of different sized baggies to put pump/CGM/OpenAPS rig into, and I also have a supposedly waterproof bag that seals that I sometimes put my bagged devices into. (More on that below).
    1. And in general, it’s always wise to have a backup pump (even if it’s non-loopable) on long/tropical/far away trips, and many of the pump companies have a loaner program for overseas/cruise/tropical travel.
  4. Apply sunscreen around your sites/sensors because sunburn and applying or removing them hurts. However, as I learned on this trip, don’t do TOO much/any sunscreen directly on top of the adhesive, as it may loosen the adhesive (just surrounding the edges is fine). I usually use a rub sunscreen around the edges of my pump site and CGM sensor, and do the rest of my body with a spray sunscreen. And pack extra sites and sensors on top of your extras.

Why extras on top of your extras? Because you don’t want to have a vacation like I did where I managed to go through 5 pump site catastrophes in 72 hours and run out of pump sites and worry about that instead of enjoying your vacation. Here’s what happened on my last vacation pump-site wise:

  • Planned to change my site the next morning instead of at night, because then I would properly use up all the insulin in my reservoir. So I woke up, put in a new pump site (B) on my back hip, and promptly went off to walk to brunch with Scott.
  • Sitting down and waiting for food, I noticed my BG was rocketing high. I first guessed that I forgot to exit the prime screen on the pump, which means it wasn’t delivering any insulin (even basal). Wrong. As I pulled my pump off my waist band, I could finally hear the “loud siren escalating alarm” that is “supposed” to be really audible to anyone…but wasn’t audible to me outside on a busy street. Scott didn’t hear it, either. That nice “siren” alarm was “no delivery”, which meant there was something wrong with the pump site and I hadn’t been getting any insulin for the last hour and a half. Luckily, I have gotten into the habit of keeping the “old” pump site (A) on in case of problems like this, so I swapped the tubing to connect to the “old” site A and an hour or so later as insulin started peaking, felt better. I pulled site B out, and it was bent (that’s why it was no delivery-ing). I waited until that afternoon to put in the next pump site (C) into my leg. It was working well into dinner, so I removed site A.
  • However, that night when I changed clothes after dinner, site C ripped out. ARGHHHH. And I had removed site A, so I  had to put on another site (D). Bah, humbug. Throw in someone bumping a mostly-full insulin vial off the counter and it shattering, and I was in one of my least-pleased-because-of-diabetes moods, ever. It was a good reminder of how much a closed loop is not a cure, because we still have to deal with bonked sites and sites in general and all this hoopla.
  • Site D lasted the next day, while we went hiking at Haleakala (a 12.2 mile hike, which was amazing that neither my site or my sensor acted up!). However, on the third day in this adventure, I put on sunscreen to go to the beach with the whole family. When we came back from the beach, I went to remove my cover up to shower off sand before getting into the pool. As my shirt came over my head, I saw something white fly by – which turned out to be 4th pump site, flying around on the end of the pump tube, rather than being connected to my body. There went Site D. In went my fifth site (E), which I tackled down onto my body with extra flexifix tape that I usually use for CGM sensors because I. Was. Fed. Up. With. Pump. Sites!
  • Thankfully, site E lasted a normal life and lasted til I got home and did my next normal site change, and all is back to normal.

Lessons learned about pump sites: I repeat, don’t sunscreen too much on the adhesive, just sunscreen AROUND the adhesive. And pack extras, because I went through ~2 weeks of pump sites in 3 days, which I did not expect – luckily I had plenty of extra and extras behind those!

Now on to the fun stuff.

Scuba Diving with diabetes:

  • 2 years ago was my “Discovery” dive, where you aren’t certified but they teach you the basics and do all the equipment for you so you just do some safety tutorials and go down with a guide who keeps you safe. For that dive, I couldn’t find a lot of good info about scuba diving with diabetes, other than logical advice about the CGM sensor not transmitting under water, the receiver not being waterproof, and the pump not being waterproof. I decided to try to target my BG in advance to be around 180 mg/dl to avoid lows during the dive, and for extra safety eat some skittles before I went down – plus I suspended and removed my pump. Heh. That worked too well, and I was high in the mid-200s in between my two dives, so I found myself struggling to peel my wetsuit off in between dives to connect my pump and give a small bolus. The resulting high feeling after the second dive when my BG hadn’t re-normalized yet plus the really choppy waves made me sea-sick. Not fun. But actually diving was awesome and I didn’t have any lows.
    • Pro tip #1 for scuba diving with diabetes: If you can, have your pump site on your abdomen, arm, or other as-easy-as-possible location to reconnect your pump for between-dive boluses so you don’t have to try to get your arm down the leg of your wetsuit to re- and disconnect.
  • I decided I wanted to get PADI certified to scuba dive. I decided to do the lessons (video watching and test taking) and pool certification and 2/4 of my open water dives while on a cruise trip last February. Before getting in the pool, I didn’t do anything special other than avoid having too much (for me that’s >.5u) of netIOB. For the open water dives at cruise ports, I did the same thing. However, due to the excitement/exertion of the first long dive, along with having to do some open water safety training after the first dive but before getting out (and doing my swim test in choppy open water), I got out of the water after that to find that I was low. I had to take a little bit longer (although maybe only 10 extra minutes) than the instructor wanted to finish waiting for my BG to come up before we headed out to the second dive. I was fine during and after the second dive, other than being exhausted.
    • Pro tip #2 for scuba diving with diabetes: Some instructors or guides get freaked out about the idea of having someone diving with diabetes. Get your medical questionnaire signed by a doctor in advance, and photocopy a bunch so you can take one on every trip to hand to people so they can cover themselves legally. Mostly, it helps for you to be confident and explain the safety precautions you have in place to take care of yourself. It also helps if you are diving with a buddy/loved one who understands diabetes and is square on your safety plan (what do you do if you feel low? how will you signal that? how will they help you if you need help in the water vs. on the boat, etc.?). For my training dives, because Scott was not with me, I made sure my instructor knew what my plan was (I would point to my arm where my sensor was if I felt low and wanted to pause/stop/head to the surface, compared to the other usual safety signals).
  • This past trip in Hawaii I was finishing off a cold at the beginning, so at the end of the trip I started with a shore dive so I could go slow and make sure it was safe for me to descend. I was worried about going low on this one, since we had to lug our gear a hundred feet or so down to the beach and then into the water (and I’ve never done a shore dive prior to this). I did my usual prep: temp basal to 0 on my pump for a few hours (so it can track IOB properly) and suspend; place it and CGM and OpenAPS rigs in baggies in my backpack; and confirming that my BG was flat at a good place without IOB, I didn’t eat anything extra. We went out slowly, had a great dive (yay, turtles), and I was actually a little high coming back up after the dive rather than low. My CGM didn’t come back right away, so I tested with a fingerstick and hooked my pump back up right away and gave a bolus to make up for the missed insulin during the dive. I did that before we headed off the beach and up to clean off our gear.
    • Pro tip #3 for scuba diving with diabetes: Don’t forget that insulin takes 60-90 minutes to peak, so if you’ve been off your pump and diving for a while, even if you are low or fine in that moment, that missing basal will impact you later on. Often if I am doing two dives, even with normal BG levels I will do a small bolus in between to be active by the time I am done with my second dive, rather than going 3+ hours with absolutely no insulin. You need some baseline insulin even if you are very active.
  • While in Hawaii, we also got up before the crack of dawn to head out and do a boat dive at Molokini. It was almost worth the 5am wakeup (I’m not a morning person :)). As soon as I woke up at 5am, I did an “eating soon” and bolused fully for my breakfast, knowing that we’d be getting on the boat at 6:30amish (peak insulin time), but it’d take a while to get out to the dive site (closer to 7:30am), so it was better to get the breakfast bolus in and let it finish counteracting the carbs. I did, but still ran a little higher than I would have liked while heading out, so I did another small correction bolus about half an hour before I temped to zero, suspended, and disconnected and baggied/bagged/placed the bag up in the no-water-shelf on the boat. I then did the first dive, which was neat because Molokini is a cool location, and it was also my first “deep” dive where we went down to about ~75 feet. (My previous dives have all been no deeper than about ~45 feet.) Coming back onto the boat, I did my usual of getting the gear off, then finding a towel to dry my hands and do a fingerstick BG test to see what I was. In this case, 133 mg/dl. Perfect! It would take us almost an hour for everyone to get back on the boat and then move to dive spot #2, so I peeled down my wetsuit and reconnected my pump to get normal basal during this time and also do a small bolus for the bites of pineapple I was eating. (Given the uncertainties of accuracy of CGM coming out of prolonged water exposure, since they sometimes run 100+ points high for me, I chose not to have the loop running during this dive and just manually adjust as needed). We got to spot #2 and went down for the dive, where we saw sharks, eels, and some neat purple-tailed fish. By the end of the dive, I started to feel tired, and also felt hungry. Those are the two signs I feel underwater that probably translate to being low, so I was the first from our group to come up when we got back from the boat. I got on the boat, removed gear, dried hands, tested, and…yep. 73 mg/dl. Not a bad low, but I’m glad I stopped when I did, because it’s always better to be sure and safe than not know. I had a few skittles while reconnecting my pump, and otherwise was fine and enjoyed the rest of the experience including some epic dolphin and whale watching on the return boat ride back to the harbor!
    • Pro tip #4 for scuba diving with diabetes: You may or may not be able to feel lows underwater; but listening to your body and using your brain to pay attention to changes, about low or not, is always a really good idea when scuba diving. I haven’t dived enough  (7 dives total now?) or had enough lows while diving to know for sure what my underwater low symptoms are, but fatigue + hunger are very obvious to me underwater. Again, you may want to dive with a buddy and have a signal (like pointing to the part of your body that has the CGM) if you want to go up and check things out. Some things I read years ago talked about consuming glucose under water, but that seems above my skill level so I don’t think I’ll be the type of diver who does that – I’d rather come to the surface and have someone hand me from the boat something to eat, or shorten the dive and get back on the boat/on shore to take care of things.

All things considered, scuba diving with diabetes is just like anything else with diabetes – it mostly just takes planning ahead, extra snacks (and extra baggies) to have on hand, and you can do it just like anyone else. (The real pain and suffering of scuba diving in my opinion comes not from high or low BGs; but rather pulling hair out of your mask when you take it off after a dive! Every time = ouch.)

Snorkeling with diabetes:

  • Most of my snorkeling experiences/tips sound very similar to the scuba diving ones, so read the above if you haven’t. Remember:
    • Don’t go into a snorkel with tons of positive IOB.
    • Have easy-access glucose supplies in the outer pockets of your bag – you don’t want to have to be digging into the bottom of your beach bag to get skittles out when you’re low!
    • Sunscreen your back well 😉 but don’t over-sunscreen the adhesive on sites and sensors!
    • Make sure your pump doesn’t get too hot while you’re out snorkeling if you leave it on the beach (cover it with something).
    • You could possibly do baggies inside a waterproof bag and take your pump/cgm/phone out into the water with you. I did that two years ago when I didn’t trust leaving my pump/receiver/phone on shore, but even with a certified waterproof bag I spent more time worrying about that than I did enjoying the snorkel. Stash your pump/gear in a backpack and cover it with a towel, or stick it in the trunk/glove compartment of your car, etc.
    • Remember CGMs may not read right away, or may read falsely high, so fingerstick before correcting for any highs or otherwise dosing if needed.

Swimming with diabetes:

  • Same deal as the above described activities, but with less equipment/worries. Biggest things to think about are keeping your gear protected from splashes which seem more common poolside than oceanside…and remember to take your pump off, phone or receiver out of your pocket, etc. before getting in the water!

Wait, all of this has been about pump/CGM. What about closed looping? Can you #OpenAPS in the water?

    • If you don’t have your pump on (in the water), and you don’t have CGM data (in the water, because it can’t transmit there), you can’t loop. So for the most part, you don’t closed loop DURING these activities, but it can be incredibly helpful (especially afterward to make up for the missing basal insulin) to have once you get your pump back on.

However, if your CGM is reading falsely high because it’s waterlogged, you may want to set a high temporary target or turn your rig off during that time until it normalizes. And follow all the same precautions about baggies/waterproofing your rig, because unlike the pump, it’s not designed for even getting the lightest of splashes on it, so treat it like you treat your laptop. For my Hawaii trip, I often had my #OpenAPS rig in a baggie inside of my bag, so that when my pump was on and un-suspended and I had CGM data, it would loop – however, I kept a closer eye on my BGs in general, including how the loop was behaving, in the hour following water activities since I know CGM is questionable during this time.

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I’m really glad I didn’t let diabetes stop me from trying scuba diving, and I hope blog posts like this help you figure out how you need to plan ahead for trying new water activites. I’m thankful for technology of pumps and CGMs and tools like #OpenAPS that make it even easier for us to go climb mountains and scuba dive while living with diabetes (although not in the same day ;)).

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UPDATE in 2023: I went scuba diving recently using a Dexcom G6, and it did not have any issues once out of the water with falsely high readings! It reconnected instantly (no delay) to my phone once I was back in range and backfilled correctly and had a correct value for the most recent value. So, this is a huge improvement beyond what I described above with earlier generation (e.g., G4 and G5) sensors, but it still has the downside that it can’t transmit data underwater. You can also read here about how I use Libre for underwater reading when I’m doing several water activities and find it worth my while to invest in a single Libre sensor for having CGM data underwater.

OpenAPS feature development in 2016

by Dana Lewis

It’s been two years since my first DIY closed loop and almost two years since OpenAPS (the vision and resulting ecosystem to help make artificial pancreas technology, DIY or otherwise, more quickly available to more people living with diabetes) was created.  I’ve spent time here (on DIYPS.org) talking about a variety of things that are applicable to people who are DIY closed looping, but also focusing on things (like how to “soak” a CGM sensorr and how to do “eating soon” mode) that may be (in my opinion) universally applicable.

OpenAPS feature development in 2016

However, I think it’s worth recapping some of the amazing work that’s been done in the OpenAPS ecosystem over the past year, sometimes behind the scenes, because there are some key features and tools that have been added in that seem small, but are really impactful for people living with DIY closed loops.

  1. Advanced meal assist (aka AMA)
    1. This is an “advanced feature” that can be turned on by OpenAPS users, and, with reliable entry of carb information, will help the closed loop assist sooner with a post-meal BG rise where there is mis-timed or insufficient insulin coverage for the meal. It’s easy to use, because the PWD only has to put carbs and a bolus in – then AMA acts based on the observed absorption. This means that if absorption is delayed because you walk home from dinner, have gastroparesis, etc., it backs off and wait until the carbs actually start taking effect (even if it is later than the human would expect).
    2. We also now have the purple line predictions back in Nightscout to visualize some of these predictions. This is a hallmark of the original iob-cob branch in Nightscout that Scott and I originally created, that took my COB calculated by DIYPS and visualized the resulting BG graph. With AMA, there are actually 3 purple lines displayed when there is carb activity. As described here in the OpenAPS docs, the top purple line assumes 10 mg/dL/5m carb (0.6 mmol/L/5m) absorption and is most accurate right after eating before carb absorption ramps up. The line that is usually in the middle is based on current carb absorption trends and is generally the most accurate once carb absorption begins; and the bottom line assumes no carb absorption and reflects insulin only. Having the 3 lines is helpful for when you do something out of the ordinary following a meal (taking a walk; taking a shower; etc.) and helps a human decide if they need to do anything or if the loop will be able to handle the resulting impact of those decisions.
  2. The approach with a “preferences” file
    1. This is the file where people can adjust default safety and other parameters, like maxIOB which defaults to 0 during a standard setup, ultimately creating a low-glucose-suspend-mode closed loop when people are first setting up their closed loops. People have to intentionally change this setting to allow the system to high temp above a netIOB = 0 amount, which is an intended safety-first approach.
    2. One particular feature (“override_high_target_with_low”) makes it easier for secondary caregivers (like school nurses) to do conservative boluses at lunch/snack time, and allow the closed loop to pick up from there. The secondary caregiver can use the bolus wizard, which will correct down to the high end of the target; and setting this value in preferences to “true” allows the closed loop to target the low end of the target. Based on anecdotal reports from those using it, this feature sounds like it’s prevented a lot of (unintentional, diabetes is hard) overreacting by secondary caregivers when the closed loop can more easily deal with BG fluctuations. The same for “carbratio_adjustmentratio”, if parents would prefer for secondary caregivers to bolus with a more conservative carb ratio, this can be set so the closed loop ultimately uses the correct carb amount for any needed additional calculations.
  3. Autosensitivity
    1. I’ve written about autosensitivity before and how impressive it has been in the face of a norovirus and not eating to have the closed loop detect excessive sensitivity and be able to deal with it – resulting in 0 lows. It’s also helpful during other minor instances of sensitivity after a few active days; or resistance due to hormone cycles and/or an aging pump site.
    2. Autosens is a feature that has to be turned on specifically (like AMA) in order for people to utilize it, because it’s making adjustments to ISF and targets and looping accordingly from those values. It also have safety caps that are set and automatically included to limit the amount of adjustment in either direction that autosens can make to any of the parameters.
  4. Tiny rigs
    1. Thanks to Intel, we were introduced to a board designer who collaborated with the OpenAPS community and inspired the creation of the “Explorer Board”. It’s a multipurpose board that can be used for home automation and all kinds of things, and it’s another tool in the toolbox of off-the-shelf and commercial hardware that can be used in an OpenAPS setup. It’s enabled us, due to the built in radio stick, to be able to drastically reduce the size of an OpenAPS setup to about the size of two Chapsticks.
  5. Setup scripts
    1. As soon as we were working on the Explorer Board, I envisioned that it would be a game changer for increasing access for those who thought a Pi was too big/too burdensome for regular use with a DIY closed loop system. I knew we had a lot of work to do to continue to improve the setup process to cut down on the friction of the setup process – but balancing that with the fact that the DIY part of setting up a closed loop system was and still is incredibly important. We then worked to create the oref0-setup script to streamline the setup process. For anyone building a loop, you still have to set up your hardware and build a system, expressing intention in many places of what you want to do and how…but it’s cut down on a lot of friction and increased the amount of energy people have left, which can instead be focused on reading the code and understanding the underlying algorithm(s) and features that they are considering using.
  6. Streamlined documentation
    1. The OpenAPS “docs” are an incredible labor of love and a testament to dozens and dozens of people who have contributed by sharing their knowledge about hardware, software, and the process it takes to weave all of these tools together. It has gotten to be very long, but given the advent of the Explorer Board hardware and the setup scripts, we were able to drastically streamline the docs and make it a lot easier to go from phase 0 (get and setup hardware, depending on the kind of gear you have); to phase 1 (monitoring and visualizing tools, like Nightscout); to phase 2 (actually setup openaps tools and build your system); to phase 3 (starting with a low glucose suspend only system and how to tune targets and settings safely); to phase 4 (iterating and improving on your system with advanced features, if one so desires). The “old” documentation and manual tool descriptions are still in the docs, but 95% of people don’t need them.
  7. IFTTT and other tool integrations
    1. It’s definitely worth calling out the integration with IFTTT that allows people to use things like Alexa, Siri, Pebble watches, Google Assistant (and just about anything else you can think of), to easily enter carbs or “modes” for OpenAPS to use, or to easily get information about the status of the system. (My personal favorite piece of this is my recent “hack” to automatically have OpenAPS trigger a “waking up” mode to combat hormone-driven BG increases that happen when I start moving around in the morning – but without having to remember to set the mode manually!)

..and that was all just things the community has done in 2016! :) There are some other exciting things that are in development and being tested right now by the community, and I look forward to sharing more as this advanced algorithm development continues.

Happy New Year, everyone!

Autosensitivity (automatically adjusting insulin sensitivity factor for insulin dosing with #OpenAPS)

by Dana Lewis

There’s a secret behind why #OpenAPS was able to deal so well with my BGs during norovirus. Namely, “autosensitivity”.

Autosensitivity (or “autosens”, for short hand) is an advanced feature that can optionally be enabled in OpenAPS.

We know how hard it is for a PWD (person with diabetes) to pay attention to all the numbers and all the things and realize when something is “off”. This could be a bad pump site, a pump site going bad, hormones from growth, hormones from menstrual cycles, sensitivity from exercise the day before, etc. So at the beginning of the year, Scott and I started brainstorming with the community about automatically detecting when the PWD is more or less sensitive to insulin than normal, and adjusting accordingly. Building on the success we’d had in DIYPS with fixed “sensitivity” and “resistance” modes, we built the feature to assess how sensitive or resistant the body is (compared to normal), rather than just a binary mode that sets a predefined response.

How OpenAPS calculates autosensitivity/how it works

It looks at each BG data point for the last 24 hours and calculates the delta (actual observed change) over the last 5 minutes. It then compares it to “BGI” (blood glucose impact, which is how much BG *should* be dropping from insulin alone), and assesses the “deviations” (differences between the delta and BGI).

When sensitivity is normal and basals are well tuned, we expect somewhere between 45-50% of non-meal deviations to be negative, and the remaining 50-55% of deviations should be positive. (To exclude meal-related deviations, we exclude overly large deviations from the sample.) So if you’re outside of that range, you are probably running sensitive or resistant, and we want to adjust accordingly. The output of the detect-sensitivity code is a single ratio number, which is then used to adjust both the baseline basal rate as well as the insulin sensitivity factor (and, optionally, BG targets).

Autosens is designed to detect to food-free downward drift, due to basal rates being too high for the current state of the body, and will adjust basals downward to compensate. The other meal-assist related portion of the algorithms do a pretty good job of dealing with larger than expected post-meal spikes due to resistance: auto-sensitivity mostly comes into play for resistance when you’re sick or otherwise riding high even without food.

Does this calculate basals?

No. Similar to everything else in OpenAPS, this works from your established basals – meaning the baseline basal rates in your pump are what the sensitivity calculations are adjusting from. If you run a marathon and your sensitivity is normally 40, it might adjust your sensitivity to 60 (meaning 1u of insulin would drop your BG an expected 60mg/dl instead of 40 mg/dl) and temporarily adjust your baseline basal rate of 1u to .6u/hour, for example.

This algorithm is simply saying “there’s something going on, let’s adjust proportionately to deal with the lower-than-usual or higher-than-usual sensitivity, regardless of cause”. It easily detects “your basals are too high and/or your ISF is too low” or “your basals are too low and/or your ISF is too high”, but actually differentiating between the effect of basal and ISF is a bit more difficult to do with a simple algorithm like this, so we’re working on a number of new algorithms and tools (see “oref0 issue 99” for our brainstorming on basal tuning and the subsequent issues linked from there) to tackle this in the future.

#OpenAPS’s autosensitivity adjustments during norovirus

After I got over the worst of the norovirus, I started looking at what OpenAPS was calculating for my sensitivity during this time. I was especially curious what would happen during the 2-3 days when I was eating very little.

My normal ISF is 40, but OpenAPS gradually calculated the shift in my sensitivity all the way to 50. That’s really sensitive, and in fact I don’t remember ever seeing a sensitivity adjustment that dramatic – but makes sense given that I usually don’t go so long without eating. (Usually when I notice I’m a little sensitive, I’ll check and see that autosens has been adjusting based on an estimated 43 or so sensitivity.)

And in later days, as expected when sick, I shifted to being more resistant. So autosens continued to assess the data and began adjusting to an estimated sensitivity of 38 as my body continued fighting the virus.

—

It is so nice to have the tools to automatically make these assessments and adjustments, rather than having to manually deal with them on top of being sick!

 

Sick days solved with a DIY closed loop #OpenAPS

by Dana Lewis

Ask me about the time I got a norovirus over Thanksgiving.

As expected, it was TERRIBLE. Even though the source of the norovirus was cute, the symptoms aren’t. (You can read about the symptoms from the CDC if you’ve never heard of it before.)

But, unexpectedly, it was only terrible on the norovirus symptoms front. My BGs were astoundingly perfect. So much so that I didn’t think about diabetes for 3 days.

Let me explain.

Since I use an OpenAPS DIY closed loop “artificial pancreas”, I have a small computer rig that automatically reads my CGM and pump and automatically adjusts the insulin dosing on my pump.

OpenAPS temp basal adjustments during day 2 norovirus November 2016
Showing the net basal adjustments made on day 2 of my norovirus – the dotted line is what my basals usually are, so anything higher than that dotted line is a “high” temp and anything lower is a “low” temp of various sorts.
  • When I first started throwing up over the first 8 hours, as is pretty normal for norovirus, I first worried about going low, because obviously my stomach was empty.

Nope. I never went lower than about 85 mg/dl. Even when I didn’t eat at all for > 24 hours and very little over the course of 5 days.

  • After that, I worried about going high as my body was fighting off the virus.

Nope. I never went much higher than a few minutes in the 160s. Even when I sipped Gatorade or gasp, ate two full crackers at the end of day two and didn’t bolus for the carbs.

  • The closed loop (as designed – read the OpenAPS reference design for more details) observed the rising or dropping BGs and adjusted insulin delivery (using temporary basal rates) up or down as needed. I sometimes would slowly rise to 150s and then slowly head back down to the 100s. I only once started dropping slowly toward the 80s, but leveled off and then slowly rose back up to the 110s.

None of this (\/\/\/\/\) crazy spiking and dropping fast that causes me to overreact.

No fear for having to force myself to drink sugar while in the midst of the worst of the norovirus.

No worries, diabetes-wise, at all. In fact, it didn’t even OCCUR to me to test or think about ketones (I’m actually super sensitive and can usually feel them well before they’ll register otherwise on a blood test) until someone asked on Twitter.

Celebrating no lows despite a many-day stomache bug, thanks to OpenAPS managing BGs

Confirming I did not get ketones

Why this matters

I was talking with my father-in-law (an ER doc) and listening to him explain how anti-nausea medications (like Zofran) has reduced ER visits. And I think closed loop technology will similarly dramatically reduce ER visits for people with diabetes when sick with things like norovirus and flu and that sort of thing. Because instead of the first instance of vomiting causing a serious spiral and roller coaster of BGs, the closed loop can respond to the BG fluctuations in a safe way and prevent human overreaction in either direction.

TIR was amazing 92-97% despite the stomach bug

This isn’t what you hear about when you look at various reports and articles (like hey, OpenAPS mentioned in The Lancet this week!) about this type of technology – it’s either general outcome reports or traditional clinical trial results. But we need to show the full power of these systems, which is what I experienced over the past week.

I’m reassured now for the future that norovirus, flu, or anything else I may get will likely be not as hard to deal with as it was for the first 12 years of living with diabetes when getting sick. That’s more peace of mind (in addition to what I get just being able to safely sleep every night) that I never expected to have, and I’m incredibly thankful for it.

(I’m also thankful for the numerous wonderful people who share their stories about how this technology impacts their lives – check out this wonderful video featuring the Mazaheri family to see what a difference this is making in other people’s lives. I’m so happy that the benefits I see from using DIY technology are available to so many other people, too. At latest count, there are (n=1)*174 other people worldwide using DIY closed loop technology, and we collectively have over half a million real-world hours using closed loop technology.)