Possible Loop bug

Tips, Tech & Gear
1

I wonder if anyone has reported this, or if anyone can try it real quick to check if they see the same thing. It might be something that has already been fixed in later versions than the one I am using.

When I set a temp basal (Loop is open), it only displays the basal adjustment for the current basal rate after an hour has passed since the rate has changed.

I know that sounds confusing! So here is a picture summary to show the bug I am seeing.

My basal rate changes at 10:00am. If I set a temp basal of zero anytime between 10:00am and 10:59am, it shows the rate change for the previous rate. Once it gets to 11:00am, the basal rate shows the change for the current rate.

Here it is in pictures:

Here are my rates between 9:00am and 10:00am.
image

Now it is 10:43am. I set a zero basal. From the rates I showed above, you would expect a zero basal drops it down -0.65 units. But what is showing is -0.75 units. That is still the 9:00am rate, not the current 10:00am rate!

image

But once an hour has passed singe the basal rate changes (an hour after 10:00am), if I do a zero basal, now the rate shows correctly. Dropping to zero, now shows -0.65 units.

image

I have retested this many times. I have even created different basal rates and tested it right after the hour has passed. The bug has been very consistent. It takes a full hour before a temp basal reflects a change to the new basal rate (in my example, the change from 9:00am to 10:00am).

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2

@Eric Your logic seems sound. I’d recommend posting to Loop ZulipChat, probably in the “development” stream and ask for the rationale to confirm if its a bug or intended for some reason and your rationale for a change. I’ve used TBs but haven’t carefully tracked as you have (they do what I’m expecting for the conditions, so I haven’t checked more closely).

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@TomH, if it is only a bug in the display, it is not too big of a deal. But if it is a bug in how much basal you are getting, then it is much more severe of an issue.

Like does it give me the 0.65 basal and just display the 0.75 value when I do a zero temp basal (no problem), or is it actually giving the 0.75 basal amount for a whole hour longer (problem!)

Is there a way I can verify how much basal I am getting? I mean other than counting pod “clicks”! I don’t see it in any of the event history!

I see boluses in the event history, and temp basal’s (both manual temp basal’s and Loop automated temp basal’s). But no record of the basal amounts from one hour to the next when you are in open loop.

It seems like basal rates should be displayed in there too.

Is there any place I can see that?

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4

If you don’t trust the display in Loop > Insulin Delivery, why not cross-check by looking at Apple Health > Insulin Delivery > Show All Data

Either way, if I set a temp basal of 0 in Loop, I see it reflected in the insulin delivery.

As far as the display issue, I don’t know whether that’s specific to your old version or if it’s still there in the current version. If I remember to do it this evening when my basal rate changes, I’ll try it and report what happens.

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Update:

@Eric , So it turns out that the new version has a different display. After setting the temp basal, it doesn’t show a delivery rate in the top display, it just says manual basal in that area. When I tap on that, it shows the pod status including the actual current manual basal, not the relative change from the scheduled basal.

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5

Yes, you could check Apple Health to see what basal and boluses you received. Also, Tidepool and Nightscout would show you the amounts. I use both. They both show visually on a graph so instantly you can see what your basals were. Im new to Loop v3.2 so have not used zero temp basals yet. I use the Overrides frequently though for exercise. If i get a chance, I’ll try it on tomorrow’s run.

Also, i know in the past, the Loop UI did not always reflect my current insulin dosages in the bottom graph. To resolve it, I would just force close Loop and reopen it. The app would then be refreshed with correct UI for dosage. That was version v2.2.9 though.

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6

@bkh,
If I am looking at this correctly, Apple Health only shows summary data. Is that right?

For example, when I have Loop open, I can see the total basal amounts given. Like from 9:00am to midnight, when Loop is generally open, I see the total basal. But it does not break it out into basal rates. Like it does not tell me the basal rate for each hour. Am I understanding that correctly?

When Loop is closed, then the Apple Health data becomes a barrage of different basal rates changed every few minutes.

Thanks for the update.

You may not be able to tell from the image I posted above, but I actually changed the display color for the graphic in mine. The purple bar here, showing that a temp basal is running:
image

Originally that bar was the same orange as the text, and that made it harder to see. When I didn’t have my glasses, without a temp basal going, I saw a blur of orange. With a temp basal going, I saw…a blur of orange.

So making that bar purple instead of orange has been very helpful for me. At a glance I can see if my temp basal is going or not, even without glasses. In other words, the only time I see purple is when there is a temp basal. That is super helpful.
(I don’t need to be able to read the number, I know what it is. I just want to see that the temp is still going.)

I have made a lot of changes to the display. I think I need to keep with my version.

The biggest problem was the lack of feedback from the Apple Watch on a bolus. Because of that I have to do a bunch of extra stuff to my version.

The big challenge for me will be trying to get the G7 into my version. But that is hopefully only a problem for next year, not this year.,

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@Eric When I open Apple Health and select “Insulin Delivery” then scroll down to “Show All Data”, it seems to list all the basal doses that Loop has administered by amount, date, time (every five minutes). Clicking on one of those shows the amount delivered, start time, end time, source of the info (Loop), date time added to the Health app, along with several other data points and info on the device. I run closed Loop almost exclusively, so there may be some difference if you’re using AB. In Loop, when clicking on “Active Insulin” or “Insulin Delivery” I get the Temp Basal rate per hour which also changes every five minutes, but doesn’t provide the finer detail.

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8

For me, what I see in the “All Recorded Data” report from Apple Health > Insulin Dosing > Show All Data is a record of every time Loop sends a command to the Dash Pod. In particular, I see entries like

0 U Basal Apr 11 at 7:01 PM
0 U Basal Apr 11 at 6:41 PM
0 U Basal Apr 11 at 6:21 PM
0 U Basal Apr 11 at 6:01 PM

So it’s not basal rates per hour, it is basal rates as set by temp basal commands to the pump from time to time when Loop thinks it needs to.

Maybe it’s different in your version. I’m running v3.3.0

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9

@bkh and @TomH,
I think the difference is that I’m mostly in open loop.

It seems to only record a basal when there is a change in the amount. During the day, that’s not very often.

But at least I understand it a little better, so thanks for directing me to Apple Health.

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