Going Untethered with Control IQ

I activated Control IQ on my Tandem X2 pump in late January. After two weeks I wrote a blogpost sharing my goals for the system:

“Unlike some seniors who are askance at letting a tech device control their insulin, I am excited. I need help. I want to sleep better. I want fewer alarms. I want BG graphs with rolling hills and valleys and fewer Himalayan peaks. I want my diabetes to be  easier.”

A month later I wrote another post indicating that I mostly liked Control IQ because of the protection from low blood sugars. At the same time I shared that I was still struggling to dial in settings with my major problem being high blood sugars after long insulin suspensions.

“I think that one characteristic of “ideal” Control IQ settings is the avoidance of long suspensions of insulin. When I say “long”, I mean one hour or more.  Unfortunately I see such suspensions almost every day. Whenever I go 1-2 hours without insulin, I always go high because I just can’t be without insulin that long. The problem is that these suspensions don’t happen at the same time or in the same circumstances each day.”

Over the next 6 months I changed pump settings more times than I can count. Stronger basals, weaker basals. Stronger insulin sensitivity factors, weaker sensitivity factors. Stronger carb ratios, weaker carb ratios. I had easily accepted that eliminating most low blood sugars would raise my average blood sugar and I was somewhat okay with that. I never considered turning off Control IQ, but I was frustrated that the system was not close to hands-off for me. My biggest problem continued to be highs after insulin suspensions and random sticky highs. BTW I was using Sleep Mode 24/7 and continue to do so.

In August I started problem-solving again. I found that when I weakened my pump settings, I got fewer suspensions of insulins but lots of stubborn highs. When I used settings that allowed me to achieve my target blood sugar levels, I had long insulin suspensions. I determined that although I really appreciate reductions in basal insulin by Control IQ, I cannot ever be 100% without insulin regardless of my blood sugar level.

I don’t need a lot of insulin but I always need some. 

I have a long history of periodically using the untethered regimen (pump + part of basal injected) successfully. It made sense to me that having some insulin on board that Control IQ couldn’t adjust might help me achieve my goals. After a few days of experimenting with how much basal to inject, I settled on 30%. I began taking 4 units of Basaglar (Lantus equivalent) every evening and reduced my pump basal settings across the board by that amount. Assuming that the Basaglar absorbs evenly over 24 hours (it probably doesn’t), it provides me with 0.17 units of insulin per hour. Minuscule.

After 5 weeks I am amazed at how successful the untethered regimen has been. That little bit of constant insulin has really helped to reduce post-insulin suspension highs and other random BG excursions. Control IQ has power over enough of my basal insulin that it continues to protect me from most lows while helping me attack the highs. Both my average BG and standard deviation are lower. Time in range is higher. The differences in statistics aren’t huge but they are significant.

The additional work of injecting basal is minor and a phone alarm reminds me to take the evening injection. I keep the Basaglar pen in the refrigerator and use a syringe to withdraw insulin because I am more confident about the dose that way. I am not discarding pens after 30 days but will use them until they are empty or there is a noticeable decline in insulin potency. At 4 units per day,  the added expense of a second insulin type is negligible.

I am sure that many of you will argue that I just need to get better pump settings. My experience is that the times of day and the cumulative time of suspended insulin vary greatly from day to day. Am I more active? Is it a new pump cartridge with fresh insulin? Is the infusion site less than optimal? What am I eating? And so on. IMO all of this indicates that “perfect” pump settings are a mirage although I continue to reduce some of my pump basal rates and tweak settings. Right now I am finding the addition of a small amount of injected basal insulin is helping Control IQ do its job better and allowing me to micromanage less. So it is a win in my book.

Is diabetes easy-peasy now? No, but it is easier. Are my numbers perfect? Not really, but they are more manageable. Will I stay with the untethered regimen forever? Probably not.

I am not saying that you should do what I do. We all have different targets and different diabetes. At the same time I encourage you to be creative as you try to optimize your Control IQ experience. Although we can customize many Control IQ settings, we are limited by the fixed behavior of other settings and the slow speed of insulin onset. Sometimes we just need to think outside the box to figure out ways to get the results that we want.

Just another reminder that our diabetes is a constant science experiment….