Medtronic 780G - first 4 weeks

I can’t find any other people’s experience of using the 780G & thought this might be of interest.
I live in Switzerland & was fortunate to be an early user of the 780G. I’ve now being using it for 4 weeks & am generally very happy.

Before switching I had been using an old Veo pump with Dexcom G6, Xdrip & FIASP.
I got good TIR (>90%) but with relatively high standard deviation (1.6) & many short term highs & lows. This meant almost every night was disturbed & I had to eat a lot of quick acting carbs to control the low BGs.

Since starting with the 780G, my TIR has improved: 14 day average = 96%
I have managed several days of 100% TIR.
Standard deviation has reduced to 1.2 (some days <1.0)
Exercise (running) is the main cause of going outside range. I’m still learning how best to control this using the ‘temp target’ feature.
Control at night is great resulting in regularly having a good night’s sleep for the first time in 10+ years.
My consumption of short acting carbs (glucose, sugar, sweets) to avoid or treat low BGs has reduced dramatically.
Average BG has increased slightly (I think) because the SmartGuard target can’t be set lower than 5.6.

SmartGuard controls BG by auto-applying basal or micro boluses.
When I’m exercising (eg hill walking) it can switch of basal for many hours (my daily basal is only 8 units normally)
SG sometimes makes unexpected actions
E.g. one evening recently, after several lows & highs, I used my BolusWizard before dinner.
I entered 45g carbs & the BolusWizard gave me no insulin!!!
I ignored this & entered an additional 45g carbs & the BolusWizard gave me the expected amount of insulin.
I was quite worried that I would get a very low BG but in fact control after my meal was OK
I discussed this with Medtronic support – their explanation was that SmartGuard thought I was trending to a low BG & consequently gave me no insulin. It would have corrected any highs with auto-boluses.
I have still not learnt to fully trust SmartGuard

Sensor Accuracy
For the first 7 days after starting on the 780G, I was still wearing a Dexcom G6 & could directly compare the results.
It seems that the Enlite is slower to react to rapid changes & often doesn’t show the highest or lowest values
This means (IMO) that my ‘better’ results are partially due to the sensor’s inaccuracy rather than a true improvement.

Pump Operation
I had heard bad reviews of some of the earlier Medtronic pumps of users getting sore fingers (!) from having to confirm each operation so many times.
I find the 780G is easy to use, intuitive & needs just the right amounts of confirmations.

Pump Display
The display is quite bright & can be read outside (even on a bright snowy day)
However the BG graph displays from 2.2 to 25 & cannot be changed. This means it’s difficult to accurately see how my BG is changing as it rarely goes above 10.0
The range should be user configurable.
The smartphone app has the same problem

Pump Size
I still think the pump is unnecessarily big compared with my Veo or the T Slim but it’s still possible to put in the pocket of my jeans instead of wearing it on my belt.

Battery Usage
The AA battery that was supplied with the pump lasted 10 days.
I replaced it with a rechargeable AA battery (Panasonic Eneloop) which is still on ‘Medium’ after a further 10 days.


Thank you @Paul. The previous generation gave people fits, really glad that is working for you. I am amused that part of your success is the sensor inaccuracy, but if it is working for you, that is all that matters. :upside_down_face: Honestly as a diabetic being able to get the tech to work for you is great and flexibility is required. It would be helpful if you could share your thoughts after a few more weeks with it, but this is a great write up.


Thanks for sharing your experiences! I’ll be up for a new pump within the next year, and I really want to move to a closed-loop system. So I’d be very interested in any continued thoughts as you gain more experience with the new Medtronic pump.


Thanks for this account of your experiences! It’s really valuable to read people’s experiences with all these new technological developments.


Is this high? I’m screwed if so!

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As a former 670G user I’d want to say “Sure, but how SOON would it have corrected them?” For me that’s the test as to whether the 780 is enough of an improvement over the 670 to tempt me back into the AID waters (I’m eligible for a new pump in March). My 670 experience was “Not ready for prime time, guys,” and it kinda burned me on the whole AID concept. Been looking at Tandem Control-IQ, but there too I’m reading that the people who are really happy with it are the ones who have been struggling to get their A1Cs down into the 6s without tons of overnight lows and whatnot. For those of us already getting tight control they may still be more of an aggravation than a help. One thing that has made a huge difference to me over the last ~2 years was my endo trying me out on Jardiance, off-label for T1 but then so is Metformin and a lot of us take that as well. Stuff has really flattened out my curves, more than the 670 algorithm ever managed.


Hi, how are you getting on with the 780g after a bit more time?
I received mine nearly 3 weeks ago. I’m pretty happy at the moment as I’ve had a huge improvement in control - nothing like your figures but great results for me which I’m really happy with.
One thing I’m noticing though this week is that the small auto corrections are not very effective. So I am staying pretty level but at 8 instead of the 6.1 I have programmed. Have you had anything like this? It would be great to hear more of your experience so far.

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Control is still overall good. High TIR & very stable BGs over night.
Yes - SmartGuard can be “over cautious” when controlling High BGs & tends to leave them too high for too long (IMO) in order to avoid over correcting & going low. Sometimes I intervene to foerce the BG down by taking extra insulin as false carbs or a false cannula fill.
The disadvantage of false carbs is that the pump provides no (or less ) auto correction boluses until the insulin from the main bolus has expired.
To minimise this problem Medtronic recommended reducing the Active Insulin Time. I have that set to the minimum of 2 hours.
Another way to avoid this problem (definitely not recommended by Medtronic!) is to instead give a false cannula fill. Auto correction should continue to work after this but of course it doesn’t take into account the insulin given in this way so there is a danger of over correction!!

My main issue at the moment is the reliability of the sensor.
• I knew it was less accurate than the G6 & was prepared to accept this, in exchange for getting the looping.
• But it isn’t only less accurate, it also requires many more calibrations than Medtronic state; often a calibration lasts only 6 (instead of 12) hours or, worse still, it requests a calibration without any warning. This means I have to carry a BG meter at all times with me when I am away from home.
• The sensor is also very unreliable. About 1 in 3 sensors fail before the 7 days.
Yesterday evening, for example, at 19:00 the pump gave a warning “Sensor Updating” & after 3 hours “Sensor failed”. I had to install a new sensor which then failed during the warm-up stage & had to install yet another sensor. This means a disturbed night, having to calibrate the sensor during the night.


Ouch! This is really brutal. I had heard that they were way better than before, but the calibration issues would be a deal breaker for me, especially seeing my son not having calibrated his sensor much at all in the last 12 months. With Tandem’s CIQ, he has become a set it and forget it diabetic for much of the day.


Is it still the case that if you don’t calibrate the Medtronic sensor in time, they TURN OFF THE CGM? That was the way it worked with the Sof-sensors and I thought it was outrageous.

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I am using fiasp, so I already have the minimum 2 hours as active insulin time, but often it seems I have a lot of active insulin but I’m not convinced I actually do! Hence, not always as on ideal target as I could be.
Ive also had some unreliability with the sensors, some itching and irritation where it is placed and then the next day it has failed.
Do you have any understanding if there is an ideal percentage of basal, bolus and auto correction? I currently have a huge amount of autocorrection which I guess isn’t ideal. I’m eating pretty low carb, but I’ve got a long way to go on getting my bolus’s correct. Ive got a lot to learn still that’s for sure!

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I don’t think there is an ideal amount of basal vs bolus vs auto correction, with that being said my goal would be to try and minimize the correction amount just because you are already eating low carb, so in an ideal world you wouldn’t be having big swings. I personally would do a basal test and try and dial that in so the system doesn’t have to work so hard.

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