I’m very excited for the future of diabetes technology, and today’s guest post is a glimpse into what the Tandem Diabetes Care’s Control IQ experience might be like once it’s released into the wild. Big thanks to Celia for reaching out to excitedly share her experiences as part of a clinical trial for Control IQ.  

This post is to share my personal experiences with Tandem’s Control IQ Software running concurrently with the Dexcom G6 CGM. I have no knowledge of any other trial participants’ experiences, and am not working for either Tandem or Dexcom.  I am a long term Dexcom user (12 years) and long term insulin pump user (25 years).

I answered the phone in May of 2018 and told the Nightlight clinical trial coordinator at the University of Virginia that I had waited 35 years to talk to her!  35 years of living with type 1 diabetes while waiting for technology to be applied successfully to produce an artificial pancreas.  The wait was long but I’m now participating in an artificial pancreas trial with a Tandem t:slim X2 Insulin Pump with Control IQ software and a Dexcom G6 continuous glucose monitor.  The Control IQ software gets bG data from the CGM and makes basal rate adjustments as quickly as every 5 minutes and also gives me boluses of 60% of the calculated amount needed, once an hour, during the day only. During the user-programmed sleep hours, no boluses are given.  The Tandem and Dexcom devices, with Control IQ software running on the Tandem Pump, is effectively the artificial pancreas I’ve been waiting for.


After using the Tandem t:slim X2 pump with Control IQ software and the Dexcom G6 CGM for 2 months at night only, and 3 weeks of using it 24/7, I feel that the combinedtrial partnership of Tandem and Dexcom has successfully created a working artificial pancreas.  Before the end of week 1 using Control IQ, I knew my life was changing for the better. At the end of 2 weeks I felt physically, mentally, and emotionally better than I had in decades.  I felt like my pre-diagnosis self again; full of energy, ready to take on the world.  Only this time I had the hard earned knowledge of a 60 year old who had battled type 1 diabetes for 35 years.

I had no idea that diabetes was making me feel so sick until the artificial pancreas made me feel so GOOD!  It was exciting waking up every single morning with my BG value between 100-120 mg/dL.

I now refer to the pre-clinical trial years as “The Dark Ages”.   During “The Dark Ages,” I raised 2 children, worked as a Computer Scientist, traveled with my husband and children, and lived what I thought was a healthy good life.  Life with diabetes was difficult and frustrating but I kept an upbeat attitude and assumed everyone had rough days.  After two weeks with Control IQ running at night, I realized that I’d been feeling BAD all those years, both physically, mentally, and emotionally.  My brain, after 2 weeks of using Control IQ, felt like it was on overdrive just from getting the correct amount of fuel from consistent good nighttime bG levels.   When the CGM/Pump warns me about an impending low, or an existing high, I also finger check my bG level to confirm the sensor is accurate, and it is amazingly spot on.  Having checked my sugar 10-12 times a day for 35 years, it’s such a relief to trust the Dexcom G6 CGM and rely on its amazing accuracy.

I’ve seen my CGM graphs stay within range 24 hours in a row due to the Control IQ basal rate adjustments and correction boluses, something that was a rarity before the trial.   As a computer programmer, I didn’t think I would easily trust a program to control my sugar, but I’m now fully trusting Control IQ and the Tandem/Dexcom device combination to control my insulin dosing24/7.  I still carb count and bolus for meals and tell the pump when I’m exercising or sleeping, but the frequent insulin dosing decisions are made by Control IQ. With just a glance at the screen on my pump, I can see all the adjustments to my basal rate, all the correction boluses the pump gives me, and my current BG value.

A good visual description of the effect Control IQhas on me is to imagine the statue of Atlas with the world on his shoulder.  Now imagine someone pushed the world off his shoulder. That’s what it felt like after the first few weeks with Control IQ running on the Tandem Pump.  After a few nights of watching the pump in action and waking up with a BG value between 110-120 mg/dL, I felt like the weight of the world had been pushed off my shoulder.  It actually felt like I was floating a few inches above the ground without all the weight of worry that every type 1 carries. My fear of not waking up from a low is gone, I don’t even think about worrying anymore at night.  Just like that, 35 years of fear is gone, and good riddance.

Imagine all the children (and their parents) and the much needed technological “guardian angel” this will bring to their lives!  I’ve watched my niece and her parents battle this disease for the past 20 years, starting when my niece was diagnosed with type 1 diabetes at the age of two. I can’t wait for this technology to be on the market, hopefully soon, to make life a lot easier for my niece, myself, and people with type 1 diabetes around the world.  This Tandem/Dexcom technology and partnership will literally save lives, it is that good. It is not a “cure,” but I will gladly accept all the help from my “buddy” – the Tandem/Dexcom combination – that I can get while waiting for the cure.  Thirty five  years doesn’t seem that long but it also feels like it has been an eternity.  I’m beginning to get used to not having lows or extreme highs anymore.  It’s a life I only dreamed about three months ago, and I dread the day the trial ends and I have to give back my artificial pancreas. My final and honest assessment of this Control IQ artificial pancreas created by the partnership of Dexcom and Tandem is that it is the second most important development in the last 97 years of diabetes care, after the discovery of insulin in 1921.

Thank you for sharing your perspectives, Celia!  

Here’s a bio, straight from Celia herself: My name is Celia Cathcart and I was diagnosed with Type 1 diabetes in 1983, 3 weeks before my 24th birthday. My favorite place to be is in the woods hiking or just sitting and enjoying the wind in the trees. When I’m not out among the trees I love to bead weave, bead embroider or play with my wonderful grandkids and grandnieces. Diabetes doesn’t keep me from having fun!

[Disclosure from Kerri, edited on 2/8 to make sure this is crystal clear: I have a relationship with Tandem Diabetes Care, but Tandem didn’t sponsor or have anything to do with this content or its publication.]

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