Caution – before you start looping

When I started looping with OpenAPS I needed ‘head space’ and time to learn, to monitor my blood glucose levels closely and adjust my settings. I kept a very close eye on my CGM. When I switched to Loop one year later, there was a whole new learning curve. You do have to be vigilant whilst setting things up and getting used to a new system.

Howard, Look, CEO of Tidepool, has just released this caution to the Facebook group, Looped. It is especially relevant to parents of children.

Please read this before you start looping. In Howard’s words… “This post is intentionally blunt and potentially scary.”

“I am posting this as a Dad who happens to have a daughter with T1D who has been using DIY Loop for some time – coming up on 3 years. (I also happen to be CEO of Tidepool. This post is about DIY Loop and is coming from me as a DIY Loop Dad.)

DO NOT USE LOOP if you do not understand the settings.

The Loop algorithm relies on settings to determine how much insulin to give. These settings are exactly the same as the settings you might have in an insulin pump using traditional (a.k.a. open loop) therapy. Loop also has two additional settings that aren’t found in traditional therapy.

If you or your clinician do not understand what appropriate values are for these settings, do not just set up Loop and use numbers that you don’t understand and assume that everything will be OK. Doing so could cause Loop to give an overdose of insulin, and an overdose of insulin can cause a seizure, coma or death.

DIY Loop does not currently put any limits on settings, so you need to be really careful and make sure you don’t enter values that could cause dangerous amounts of insulin to be delivered. Here are some examples:

Correction range: This used to be called “target range” in previous versions of Loop. It is the range that Loop tries to keep your blood glucose in. A correction range of 100-120 mg/dL (5.5-6.6mmol/L) is a reasonable range. To be even more conservative you might want 110-130 (6.1-7.2) or even 120-140 (6.6-7.7).

A correction range of 20-40 mg/dL (1.1-2.2mmol/L) is NOT a reasonable setting for anyone, and is extremely dangerous.

(Mary Anne here: I used 120 mg/dL (6.5-6.5mmol/L) as my correction range (BG target) when I first started looping and only reduced it to 100mg/dL (5.5mmol) after a few weeks once I had reassured myself that the settings were working safely.) 

Insulin Sensitivities: This is also called “correction factor” in your Omnipod PDM. This is the amount of BG drop that insulin will cause. 50 mg/dl/U (2.8mmol/L/U) means that 1 Unit of insulin will cause a 50 mg/dL (2.8mmol/L) drop in BG. That’s pretty typical for an adult. Kids are typically much more sensitive, meaning insulin causes more of a drop. It’s not uncommon to see have an ISF of 80 (4.4), 100 (5.5) or 120 (6.6) in kids. Higher numbers are more conservative.

An Insulin Sensitivity of 1 mg/dL/U is NOT a reasonable settings for anyone, and is extremely dangerous.

Basal Rates: These are the underlying level of insulin that your body needs, and it typically varies slightly over the course of the day. Kids often have basal rates in the range of .25 Units per hour to .50 Units per hour. Adolescents may go up to 1.0 Units per hour. Adults are typically in the .75 to 1.0 range.

A default basal rate of 10 Units per hour is NOT a reasonable settings for anyone, and is extremely dangerous.

Carb Ratio: This is how many grams of carbs are “covered” by one unit of insulin bolus. If you don’t know your carb ratio… wait – don’t start Looping yet. Speak to your endo or health care provider to determine your value. You should not just enter a “placeholder” value without having some idea if it is representative of your insulin needs.

These are just a few examples. Again, if you do not have insulin pump settings that you already trust or think are at least close to accurate, do not just start Looping! If you do, make sure you put the right settings in the right places. Don’t get Correction Range and Insulin Sensitivities mixed up.

This blog post may be helpful to you to understand if your pump settings are similar to what other people use. As will be clear if you read the article, there are wide ranges for every setting, for every age, so you really should test your settings and work with your care team:

This web site has great tips on how to test and optimise your settings for Loop: .

The Looped Facebook group also has hundreds and hundreds of posts/comments encouraging people to test their settings prior to using any DIY looping system, please respect that advice.”

(Mary Anne here: Please note that some adults can be very insulin-sensitive too. One unit of insulin reduces my blood glucose levels by over 9mmol/L (162mg/dL). As someone with extreme insulin sensitivity I have seen first hand how much variability can occur and how difficult getting meal boluses right can be. Better to be conservative and safe, especially with your precious children.

Another factor that needs to be right for safe looping is Duration of Insulin Action (DIA). Please read Tim Street’s excellent blog post on ‘Why we are regularly wrong in the duration of insulin action (DIA) times we use, and why it matters‘ before you set your DIA.

DIY ‘loopers’ take diabetes into their own hands

I was interviewed as part of an ABC Science Show program on DIY looping which was broadcast last weekend. Wonderful coverage of what it’s like to live with Type1 diabetes psychologically, two peoples’ experiences of using a DIY system, and why we need to get CGM coverage for adults in Australia ASAP.

Jim Matheson, one of the first 16 people to build a DIY looping system, was also interviewed, along with endocrinologist, Tien-Ming Hng.

A man looks at his phone which has graphs and numbers on it
Jim Matheson with the DIY Loop app on his iPhone (Photo by James Bullen, ABC)

It really is a fantastic piece. It covers:

  • what it was like to live with diabetes 40 years ago
  • the precarious nature of keeping blood sugar ‘not too high, not too low’
  • DIY artificial pancreas tech overview
  • how immediate and dramatic the changes were for two people with type 1 diabetes when they started using the systems
  • a plea to government to subsidise CGM costs in Australia by shifting money from the complications end of diabetes care to the complication-prevention end so that all can benefit from the technology that’s about to arrive at our doorstep

Listen to the podcast or read the transcript here

Sensory recalibration with Looping

People in the DIY artificial pancreas community are talking about sensory changes in the way they experience their diabetes.

Some, like Thacher Hussain @Thachert1d, find that DIY looping causes them to regain their hypoglycaemia awareness.

“Feeling shaky at 84… means #Loop is keeping me in range enough that my body’s own hypo-awareness is readjusting to my goal range of 80-180 and (according to #DexcomClarity) only 6% under 80 in the last 30 days… #holyshit this is amazing”

Others like Tim Gunn @TwistaTim found that once they were looping they had less tolerance of blood glucose levels higher than normal range.

Before looping I used to be much more tolerant to a high BG, but with Looping, my body must have got used to me having such good control, when I have a High BG now…. I feel like crap.

For me, a sustained period of building trust using OpenAPS and Nightscout technology allowed me to finally let go of the thing that had haunted me for decades. Normal blood sugar levels feeling like ‘living on the edge of a hypo.’

Just looking at the ambulatory glucose profile (AGP) gives a clue as to how this normal (euglycaemic) glucose homeostasis re-establishes itself.

Two months prior to looping with OpenAPS (March-May 2018)
First three months of looping (May-August 2018)
Ah… stability Jan-March 2019

I am planning to write more about the psychological and behavioural aspects of this over the coming weeks. In the meantime, if you have experiences to share, I’d love to hear from you. Please leave a comment.

2 weeks in hospital 1980

The children’s ward was a bright and colourful place, and the whole two week experience was actually ok, apart from my first hypo. My memories after 39 years are a little vague, but here is what I do remember…

One morning, just after I finished breakfast, in bounced Julie. Julie was young and full of a tingly kind of energy, probably in her early 20s. She oozed warmth and fun and she introduced herself as my ‘diabetic sister’. I thought all my Christmases had come at once. Diabetes seemed like one big adventure with Julie.

There were rules and they seemed easy enough to follow (in hospital at least!). We had ‘portions’ of carbohydrate and a book to show us what things equalled a portion. One slice of bread, one banana, one potato. I had a food plan. Three portions for breakfast, three portions for lunch and three portions for dinner. One portion for morning tea, afternoon tea and supper. 3-1-3-1-3-1 made me think of a piano scale.

The book with the ‘portions’ in it I just called ‘the red book.’ It explained everything I wanted to know about diabetes. It was easy to read and practical.

The best thing about ‘the red book’ was the page with the circuit diagram of the technology that scientists were busy working on. The Artificial Pancreas. The Closed Loop. I loved that diagram, and once diabetes got hard after I left hospital, I turned to that page a lot. Around ten years later, when I was diagnosed with proliferative retinopathy, and told I had a 50% chance of going blind without laser therapy, I remember trying to find the book again, but it had been thrown out.

The other good thing about the book was a list I called the ‘forbidden food list’. (I can’t actually remember what it was called, but at one stage I actually did have a list with the title, ‘forbidden food’.) It had things I could buy at my school tuckshop in it with the equivalent portions listed. One Dracula ice cream equalled 1.5 portions.

I had one injection a day in the morning. It was pork insulin. Hypo signs were intense and easy to recognise, which was lucky, because we had no BG meter, just urine testing tablets.

My mum came to see me when she could. She learned to inject an orange first, then me. Like others, I found the injection by my poor mother was the only one that really ever hurt.

One day a very good looking boy about my age was wheeled into the ward and placed in the room I had been in for the first two days while I was on the drip. We were the two oldest kids in the ward. He called out at night, moaning as though he was in pain, and sometimes he called out during the day too. There was always someone sitting with him, next to his bed. Almost always his parents. I used to skulk past trying to get a look at him, and once I caught his eye. I felt so sorry for him, alone in there with all those adults, but what could I do? One day when my ‘diabetic sister’ came to visit I asked her about him and she whispered that he had a brain tumour.

Every day a lovely paediatrician came to see me. He was a round man with a kind, smiling face. His mother had had type 1 diabetes and he used to give her her injections apparently.

Another memory from those two weeks was that I was super anxious at missing two weeks of school. I knew there was a Maths test planned for the day I got back. I panicked and figured I would fail the test as I’d miss so much work. I had to rely on the textbook. It was hard going, working through the worked examples and extremely detailed explanations for everything, and I had to go over pages a few times to make sense out of them. I showed up that first day back at school, carefully measured milk in my drink bottle (one portion), urine test tablets and test tube in my bag, sat the Maths test and was completely gobsmacked to get a score of 100%.

It was the only time in my life I got 100% in a test and I wish I’d realised the significance, the ‘take home message’. Read the documentation. Find the answers yourself and check them. There was no internet then. The only information we had was from doctors and the quarterly magazine from the diabetes association, which was peppered with dire warnings, people who were older than me, and anxiety-inducing outcome data that I didn’t realise applied to the previous generation. I read every word.