Switching from 670 to t:slim

I am so glad my endo recommended this forum! I have has TD1 for almost 30 years. I have been a pump user for almost 20 years. My first pump for 16 years was the Desitronic. Second type was Medtronic 630, ?, and now Medtronic 670g with Guardian 3 sensor. I love this pump, but do get irritated with the excessive alarms. The alarms wake me up, or interrupt during meetings, or when presenting in front of large groups. Warranty is expired and the pump and Sensor are acting up. My endo wants me to research the t:slim x2 with the Dexcom G6. I don’t like change! But learned I needed to change after moving on from the Desitronic. On the 670 I have lost weight, my A1Cs are in the 6.8 to 7.2 range. My peaks and valleys have flattened. My quality of life is better. I am willing to change, but fearful I will not be as happy with the t:slim Dexcom combo. Can anyone offer some insight into the t:slim Dexcom combo? Has anyone changed from 670 to t:slim and been happy with the results? Will the Dexcom work on my forearm? If I stay with Medtronic, I will go to the 770. Any info on the 770?

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Hi @Aggies. I have been using Tandem with Dexcom for quite a while and upgraded to the Dexcom G6 with Control IQ a few months ago. I’ve never used Medtronic Guardian so can’t compare - although there are lots of forum members who can - but I’ll share what I can.
As you may know Dexcom offers two programs: Basal IQ - which corrects for lows only; and Control IQ which handles both lows and highs.
There is a TSLIM simulator app you can use to get the feel of the system on your smart device. As with Medtronic’s system, staying in range and minimizing peaks and valleys will depend on having good background settings. I imagine you have a head start since things are working well on your Medtronic system. As for Dexcom forearm placement, last I heard that was not an approved site, but I use it myself and it works just fine. Dexcom will replace trouble sensors if you have an issue, but I’ve heard that may not be the case if you do not have doctor’s approval to wear it there. I heard that somewhere a while back and there may be more current info available. I’ve had very few issues with my sensors and never on the arm bit others may have experience.
I first switched from Minimed to Tandem because I loved the sleek look and feel - at the time I believe they were pretty equal add far as bells and whistles were concerned - at least those important to me. You may appreciate knowing that people who make the switch notice that filing cartridges takes longer than with the Medtronic pump. It’s something to get used to.

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Hi @Aggies. I just switched from Medtronic 670g to the Tandem t:slim & Dexcom G6 within the last month. My Medtronic pump warranty expired in October. I was excited to see the new Medtronic models and was starting process to upgrade, when I received a friendly push from my NP to check out Tandem. I’m not good with change either. I thought I was doing just fine on Medtronic, even though I managed it through manual mode because auto-mode had too many alerts, alarms, and errors. However I decided to at least research t:slim (Tandem/Dexcom websites, JDRF forums, reviews, and talking with reps). What really pushed me to switch was the 30-day trial period. If you don’t like it within 30 days, you can return. Pretty low risk, so I made the switch. I really liked Tandem t:slim technology, especially the sleep activity. This was my biggest issue with Medtronic. No matter what I did, my levels always increased at night. I’m happy to say with Tandem, this is no longer an issue. There are a few things that you should know before switching: you get your supplies from different vendors (unless you go through distributor), most of your product issues start with Tandem, but if you have sensor hardware issues or bleeding, you’ll most likely need to contact Dexcom, the cartridge change is slower and requires different technique, although I feel it is better designed (with the exception that there is no way, at least that I know of, to recover insulin, so be as precise as you can), Dexcom is remarkably accurate, but I’ve had a few issues (at the beginning sensor was off more than 20%, but it resolved in ~1 day and I haven’t had an issue again; also had issue on the 9th-ish day with sensor not available alerts, but they usually resolved within an hour). Moreover, I had multiple cracks with the Medtronic 670 and newer models are the same design. The t:slim is much better. Also nice that you can just recharge during shower and not have to put in a battery. I’m excited to see what my A1C is with Tandem. It’s been in the mid-to low 6’s with Medtronic (which is the only system I’ve been on), but I have a feeling it’ll get much better with Tandem. Also, Tandem is closer to FDA approval for delivering bolus from phone, if that’s of interest to you. Both Tandem & new Medtronic models can be viewed on phone & can get software updates, so wouldn’t base your decision on this. It’s been an easy switch between Medtronic & Tandem infusion sets. Overall, I’m happy with my decision to move to Tandem/Dexcom combo. However, pumps/sensors are personal and you should always do what feels comfortable to you. Hope that helps!

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@Aggies Hello Tracey, and Welcome to the JDRF TypeOneNation Forum!

I currently use a Tandem t-Slim x2 pump and a Dexcom G6 sensor, after having used three progressively improved MiniMed pumps. Although the last two Medtronic pumps I used would pair with Guardian sensors, I didn’t use those sensors because of their low accuracy. I began using the Dexcom G5 sensors with my last MiniMed pump when CMS approved use by Medicare Beneficiaries; the accuracy of this CGM really helped me. Two years ago I got my Tandem pump, and last year when Control IQ [CIQ] was approved began using that algorithm.

CIQ has worked wonders for me, and I enthusiastically endorse its use. CIQ has helped me lower my standard deviation, and continues to maintain me “in-range” well over 90% of the last 11 months. I’m in my 64th year trying to figure out this “diabetes mystery”.

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I have had 670G, then switched to Tandem/Dexcom, have used ControlIQ since shortly after CIQ was available.

I WOULD NOT SWITCH BACK. Dexcom sensors are so much better. Tandem pump + CIQ is very impressive.

Hi Tracey.
I made the switch a few months ago. It WAS very stressful for me, because it is a big change. I think others have mentioned that TSlim takes longer to fill cartridges (there were some tears the first few times) BUT, once I got through that initial phase of getting used to filling a teeny tiny cartridge with a teeny tiny syringe, I would never, ever think of going back! Glad to hear Medtronic sensors worked for someone–they never did for me. But I pushed ahead from using Libre sensors to using Dexcom with the Tandem pump. CIQ is amazingly superior to anything else IMO. It completely smoothed out all my lows and took the tops off the highs. I found this forum very helpful when I was making the switch so glad you checked in! So much good advice here.

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Just noticed your last question about Dexcom on the forearm. I have only used it on stomach, because I can’t use that area for infusion sites anymore. No pain, very easy, very reliable. I think though that you can use it on the arms–although I suspect pumping it off might be a problem. Good luck!

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Hi Tracey @Aggies, in addition to what I wrote a couple of days ago, I want to add a couple of thoughts.

  • Change can be a trying time for me too, except when things are not going really smoothly. For me, my change to Tandem t-Slim from the Medtronic paradigm didn’t “frighten” me even though I had had good experience with my other pumps. One thing that I did, was install the Tandem simulator on my tablet and “worked” with it there and felt comfortable. The change was good for me.
  • I strongly recommend that you use the t-Slim for a little while before upgrading to Control IQ, become familiar with pump features and make certain that your “rates & ratios” [Basal, Correction Factor, Bolus ratio] are correct and working well for you; the automatic corrections that CIQ will make are based in what you have entered, especially insulin sensitivity for various times of the day.

Another note, a feature you will like about the Dexcom G6 is, that unlike Guardian, “non-adjunctive”, meaning that the pump can calculate insulin dosing based solely on the sensor value.

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I’m about to jump from the 670 to the 770. It sounds like a big improvement, more user friendly.
Like the Tandem, it will provide software updates. The 880 is around the corner as a software update. I’ve been using pumping with Medtronic since 2008. For me, they’ve been responsive.
This a link that includes a review of the 770. I respect any decision a fellow D-traveler makes.
Hot New Technology from Medtronic Diabetes (healthline.com)

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I switched from Medtronic pump 670G and guardian infusion sets about a month ago. I had been on Medtronic pumps for about 20 years. The TSlimx2 with control IQ and Dexcom G6 are a game changer. Much more intuitive. You won’t regret it.

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Thank you all for taking the time provide advice and info! The filling of the cartridge is good to know. I have had diabetes for a long time, but I am always amazed how much I don’t know. Everyone sharing their insights is very helpful! I needed some life experiences to help me make an informed decision. I am going to do more reading, check out types if infusion sets, and make my choice. I am thinking the T:Slim might be the move i need. Especially after a night of nonsense pump alarms! Pump therapy is/was a positive life change for me and moving forward is exciting. Once again thank you all!

The only difference between the 670 and 770 is the Bluetooth. Not a single different thing. I have used it for a month. The next one is the one with real promise. It corrects for highs and lows. It is being used in the EU now. I hear it’s either 780 or 890 but Medtronic refuses to say even though the same people we call support the EU.

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After reading the above replies - it sounds like everyone is saying what I’m about to say - Tandem is better! I am currently on the 670 and my 10 yo started Tandem about 6 weeks ago. I am jealous! My pump isn’t available to switch yet, or I would! The first thing I noticed, was, there is no real start up period. You are entering your own basal settings, and Control IQ is using that to make adjustments. 670 spends time learning you, and may take a few weeks to figure you out. Control IQ is ready to work and make appropriate adjustments right away.
The only Dexcom complaint, is it seems like the 1st 24 hrs aren’t always accurate. We do more fingersticks during the 1st 24 hrs. Otherwise, it works great!
I would make the switch!

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I just switched from 670g to tslim x2 in November. I am thrilled with the dexcom accuracy. I am not thrilled with all the trash this combo generates. The insertion device is disposable with dexcom and a special syringe with insulin cartridge is also disposable. I have had multiple issues with the needle not retracting out of the dexcom inserter, and it hurts. I am still on the fence personally about the switch. Personally as a busy person who works and spends much of my free time outdoors I miss just being able to replace my battery. I hate having to be plugged in. Tandem said plug it in when I shower but I don’t take long extended showers and it is never charged up. Time will tell me if I made a good choice but both of my last A1c results with 670g were 6.5 so I was happy with the results.

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@jdiesel, if it helps any, I plug my pump in while I’m watching TV, sitting at my desk, lying in bed, or even riding in my car. I’ve even used one of those “charging bricks” or chargers that look like an oversized lipstick. I find my TSLIM charges fully in 30-45 minutes, perhaps depending on the strength of the charger. I actually like not having to worry about having batteries on hand (as I recall the watch batteries I used when I had a Minimed pump were expensive) but everyone has their preference. Hopefully in time it will become second nature.

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Has anyone switched to 770 and wished they would have chosen t=Slim instead? I’ve veen on Medtronic pumps for 30+ years and loved them, until the 670 with CGM. It is now out of warranty and I need to decide whether to wait till Medtronic delivers the highly promised 780 or switch now to T-Slim. Given the false promises of the 670, I don’t know if Medtronic will be able to deliver on ALL the promised fixes. Any thoughts??? thanks.

hi @DiabeticDream and welcome to Type One Nation. the success of tandem or medtronic rests on how you get along with the CGM. can you try the G6 and see if it works for you… if it is great… then the question may be much easier to answer.

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That is a great idea! Thank you, will send msg to Endo to order for me.

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Great plan! Good luck :four_leaf_clover:

If that doesn’t work out, you also could spend some time in the European forums where they discuss their experiences with the 780 so far…they seem generally happy with it but they haven’t had it that long yet.