Closed loop: I want a "well-controlled patient" pump

The feedback over the Medtronic 670G pump has been interesting.

The Medtronic 670G is the first pump officially approved to adjust insulin dispensation following the input from a CGM sensor – the so-called “artificial pancreas”, although it is very far from being one: in one direction, the only thing it knows how to do is suspend insulin in order to avoid lows, but that’s already so much more than before!

I think we all expected great things from the technology – one nagging concern being the constraint that the BG goal would be 120: many of us aim lower. Still, as @drbbennett points out, 120 means an A1c of 5.8, a very good number, in particular if it comes without lows.

What we have seen is a dichotomy in feedback:

  • many patients with less good control give great kudos to the pump: their control is much better, and they are avoiding lows, in particular night time lows, which we are all worried about;

  • but well-controlled patients, who already maintain good control almost always at a significant price to themselves, are not so pleased – many appear to report, at least at this stage, that they do see better control of lows, but at the cost of overall quality of control, which is worse than it used to be.

I understand why an epidemiologist, or the FDA, would favor this approach. They are worried about the patients in the 8s and 9s (or worse) – they want a solution that will work for these patients. They look for averages, and want to improve them.

But I – we, my family – don’t look for averages. We work very hard on our BGs. We stay up at night when we need to. We test and experiment to figure out what will work better. We spend hours every day reading up on how to manage BG better. We learn from others.

The outcome is – we do succeed in keeping BGs in check better than if we weren’t working so hard. We are the good patients that I think most endos should wish for (although many obviously don’t): we actually try to do what our PCP wants us to do.

Unfortunately, the Medtronic 670G is not geared towards PWDs or CWDs like us. So this is what I want:

  • a pump that will allow me and my family to get to the same BG control that we have today, but without all the pain we have to undergo

  • a pump that will allow US to make the choices that WE think are appropriate for OUR treatment and OUR diabetes

  • a pump that will give us better control of lows, without compromise on overall BG, at OUR decision.

I want a “well-controlled patient” pump!


So, Michel, are you completely satisfied with the Omni pod? Or do you want something that provides a more robust treatment algorithm to give you suggestions?

If I was a hypothetical $100B company, I would target the patients with the 8+ A1c. This is likely the far larger group of poeple and much easier to deal with. Probably not as many questions about how to tweak, tailor and personalize the technology.
Let the other little pump companies deal with all those “difficult” patients who want lower A1c.

Perhaps an overly cynical point of view.


Not cynical. Very realistic. The big pump companies are in the business for the purpose of making money. They can make more by targeting a bigger group of people.


Also if I were the government, I would devote research money to targeting the 8+ A1cs as well, since those are the folks driving up health care costs. I write NIH grants as part of my job, and writing a compelling/fundable grant for that would be way easier than writing one for easing the burden for already well controlled patients, much as I agree with hoping that something along those lines eventually comes out. I suspect once the technology improves, it will be adaptable to our purposes though—this is just such an initial rough version of it, it makes sense it’s not there yet.


I think the picture will become less murky when a couple of the smaller pump companies release their own FDA approved closed loop solutions.
Will they be following the footsteps of the commercial giant? Or will they be taking the more challenging route. I could really see it going either way.


Somewhat related, to this :arrow_up: , I have applied for many clinical studies and every single time I was told my A1C is too low. It was explained to me that companies want the clinical studies to show improvement, and they would not be able to show improvement with an already low A1C. That is why so many of them set their clinical study requirements to have a higher A1C level to qualify.


We are trying to get into a closed-loop trial.

One of the requirements: HbA1c level <10.5% at screening
No minimum A1c mentioned but you never know how people are selected actually from those that are eligible.

Closed loop trial involving TypeZero, Tandem and Dexcom is what caught our attention.

Sponsors and Collaborators (NCT02844517)
University of Virginia
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Jaeb Center for Health Research
TypeZero Technologies, LLC
Tandem Diabetes Care, Inc.
DexCom, Inc.
Roche Diagnostic Ltd.


That’s cool! Good luck!


Yeah, you need to be able to have some sort of outcome measure, so if someone is already at target control, that’s not usable as one. Things like “how stressful is your diabetes care” are viewed as a lot less compelling of a finding to publish than “this intervention significantly lowered A1cs,” even though we and probably many endocrinologists would argue both are important.

Yeah, and furthermore, just because you meet the guidelines advertised doesn’t mean you’re actually eligible for the study. Most researchers do not disclose many of their studies’ eligibility requirements in advertisements, in part because we don’t want people to tell us what they think will get them in vs the truth, especially for any factors that are just self-reported.


At least this trial has publicly listed 12 criteria for inclusion and 8 for exclusion so even if they have additional private criteria (which seems likely), at least we have a reasonable idea if we are obviously not well suited for the trial.

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I am very satisfied with the physics of the system so far.

But I would love to get a closed-loop system, in particular for night. I am mostly worried about college for my boy, when we are not around anymore. I have great hope for openaps btw – #IamNotWaiting for a pump manufacturer if I can get closed-loop going on a Pod.


Insulet is targeting 2019 for their closed loop version. So even if they are delayed a year, K still could have that for college.

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I am in the market for a pump and CGM for my son. I actually got so excited about the upcoming 670g that I held off on getting a Dexcom for him until we made a pump decision.

Now after reading the reports on the 670g, I realize that it may not be the pump I am looking for.

What is truly disappointing, is that the existing OpenAPS/Loop/AndriodAPS design philosophy is so much better (for someone trying to go for great control) than the 670g.

So - moving forward for my son I have a choice of Omnipod, Animas, and Medtronic in Canada. I would prefer a tubeless Omnipod for him, but the downside of the Omnipod is the 0.05U/hr minimum basal rate) I was thinking maybe going Animas (soon to be an ex-company?, no development pipeline) or Medtronic (exciting new closed loop !!! and 0.01 U/hr basal.) but now think that Omnipod is the only option.

It looks like the openOMNI folks are getting closer to a closed loop pod (it is a huge task as they need to replicate the entire PDM functionality in a safe way), so that is where I have my hopes pinned right now.


If the 670G was available in Canada, I’d get it in a heartbeat. (My Ping is literally falling apart.)

I’m a “well-controlled” patient, but my control varies widely, from periods of calm where I can manage very tight control on my own, to hormonal-induced periods of chaos where I struggle just to keep more than 20% of readings within range.

If I had the 670G, I would run the pump on manual half the time and flip it over to automatic during periods like the one I’m having right now, where I’m dealing with not only an increase in exercise compared to what I’m used to, but due to hormones have had to increase my insulin by more than 60% (even running +200% basal rates for hours at a time) yet at the same time cannot go low because of the practicum I’m currently doing. A target of 120, sure, but that’s better than the swinging between 2.5 and 16.5 I’ve done for the past three days, and ther’s protection against lows which is something I worry about during times like practicums. Even when I’m at home, because of all the extra “stuff” I have to manage from day to day, there are periods where I just get so damn sick of diabetes and would love to be able to set a pump to automatic for a few days to take even an iota of a break.

Of course, the only downside is that it doesn’t use the Dexcom, which I love… Otherwise, I’d get it without hesitation. Maybe something like OpenAPS is the best choice for me, but it doesn’t seem like that works with any modern/waterproof pumps, and I can’t use the OmniPod due to infusion set reactions.


A couple points to mention.

Your son would probably grow into this very quickly. Where is he now in terms of basal? @ClaudnDaye’s boy Liam is using it, and he’s…3 maybe?

I can put you in touch with the Animas rep I know. She is great, and would be able to answer questions about this.

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I agree with Eric that your boy will outgrow this quickly.

Yes - high risk here.

Well, the 670G still is a good option, just not as good as we hoped, imho.

This is my #1 hope also. I will be ready to be among the first to try it out.

.05 is plenty small enough, even for someone Liam’s age or younger. Most of our daily insulin comes from bolus, not basal. 30 - 40% is usually basal - the rest bolus. The .05 is plenty small enough for us and, when we need less, we just suspend basal delivery for x amount of time…but that hasn’t happened in months.


Very similar to my thoughts on the Tandem t:slim X2. Tandem is targeting late 2018 for their closed loop. Even with a two year delay, that would work out nicely for our college plans.


Somewhere between 1.5 to 2 units of levemir per day. 0.05/hr should be fine, but 0.025/hr seems better.

I would like to know if they have an R+D program and if they are developing new products. There was noise about a pump being released with HHM (Hypoglycemic-Hyperglycemic Minimizer) - would love to know if this is actually happening.