T-Slim Pump & Control IQ Mode

Hi @AMP2 and welcome to the DCUK forums.
I was put onto the tandem tslim about 18 months ago, in order to help with hypos, which I'd been having far too often. My previous treatment was lantus and humalog, and I found the lantus hard to get on with, even with a split dose.

While it's by no means perfect it has dramatically reduced the number and severity of my hypos. My dexcom g7 record has < 1% low all the time and 0% very low for the last two weeks with <1% very low if I go out further. I've also noticed improved hypo awareness because I am spending so much less time under 4mmol/L.

But it isn't perfect. You have to manually set your basal rates and carb ratios so if your needs change then you can just end up with too much insulin in your system. And if your pump loses contact with your cgm it won't necessarily pick up the start of a hypo.

How much help have your diabetic team given you with tweaking the various pump parameters?

Having said all that, pumps aren't for everyone, and not all pumps are the same. Maybe you'd be better off with a different pump or going back to MDI? But personally, I'd hate to be without mine.

Tagging @Juicyj who is also on a tandem and has more pump experience than me.

Once more welcome

Have you tried putting your pump on sleep mode? This is a bit of a stepping stone as it is technically on basal iq, it will only try to bring your sugars down by increasing your basal rate which I find suits me better. I don't want it to give me a correction bolus if I am about to start some physical exercise and if I'm not then I just add a basal correlation myself. Also I take most of my blouses on an extended/split bolus so it doesn't hit hard and fast.

Hello @AMP2 I have been using the t slim with Control IQ around 4 years now, I can honestly say for the first 2 years I was sat on the fence and wasn't sure it was the right pump for me, still having hypos and control was ok but not great, I used the Medtronic before without a sensor so was doing all my boluses manually and achieved a HbA1c of 42, it shot up to 54 with T slim. Background, I am also perimenopausal so hormones were erratic which also affects control, however on HRT now so more of a level playing field.

Here's what I learned..

Getting ratios correct was vital, so splitting my basal rates into 5 patterns throughout the day and basal testing to get the ratios tweaked and fine tuned was vital.

Easing off the manual pedal was vital to let control IQ and the algorithm intuitively learn my patterns, I was too hands on and ghost carbed and corrected highs too often, taking the foot of this pedal was vital, hitting a hypo meant playing the yo yo game with control and I was fighting control IQ too often, once I learned to back off and let Control IQ do it's thing then my control improved.

Switched from Novo to Lyumjev and things stepped up a gear here too - its a fast acting insulin so starts working pretty much straight away and although it's painful at infusion site, the benefit of having better control outweighs the pain bit.

Make sure your weight is up to date in the pump settings, this is vital.

I wouldn't opt for sleep mode in your current position - getting your basal ratios correct is your first job, do some basal fasting, if your unsure how to do it then use https://www.mysugr.com/en/blog/basal-rate-testing

I now also refer to Time in Range for my control guide and if i'm hitting around 80% am happy (NICE guidelines is 70%). I still have hypos but incredibly rare to have one below 3.4mmol/l and generally around 2-3 a week but exercise alot and this affects my control too.

AMP2 said:

Hello Sninge,

Thank you ever so much for your reply.
The DSN didn't mention the sleep mode but has now suggested running the pump in activity mode for a few weeks to help me gain confidence with the Control IQ.
I have a Call with the DSN early next week and have decided to return to MDIs and my previous and preferred insulins as opposed to Novorapid which I just cannot work with. I had asked to switch to Lyumjev in the T-Slim but this was refused.

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Lyumjev isn't licenced for the t-slim that's why they would refuse it, my DSN is more proactive and has a few of us on it now - it's really down to your DSN to ok it. If you weren't switching back to MDI I would suggest you try a different approach with your team and ask to work closely with them, gain trust and build a good relationship suggesting regular contact and to trial it for a month, I contact mine via email which allows for a more proactive relationship as she can reply when free and i'm not chasing her down then. Good luck with whatever decision you decide but try to view this for the long game and not quick results now - MDI will help short term but to get your t1d on track it would help if you could bear with the pain now to get the algorithm working properly - your DSN was right to advise against battling control IQ, once it has a chance to learn patterns it will make life much easier for you.

Lyumjev wasn't approved for the tslim and like you I was lucky enough to have a proactive DSN who allowed me to use it. However, as of September 2024 it has been approved, so it might be all the teams are aware yet. You just need to be aware it doesn't like being left for more than 3 days in your pump, it causes occlusions.