May 2019 Snapshot of UK DIY APS Users

For the duration of May, I ran a survey of UK DIY APS users. Having closed the survey now, this is the overview of the data captured.


In summary, 148 people responded to the survey from the UK. This is an increase of 66 from the previous survey run in August 2018, showing a 80% increase in the number of people looping that responded to the survey.

Once again, AndroidAPS is the most popular system in use, increasing its share of the userbase, while Loop remained similar and OpenAPS dropped off quite substantially.

What’s also changed compared to the previous survey is the type of pump in use. We can see that the share of userbase of the Sooil pumps has practically double while the use of Medtronic loopable pumps has practically halved. We see that the percentage of people using non-loopable pumps has dropped off, while Omnipod users have increased from 3.6% to 12% of the looping population. 

Finally, the other item that we asked about on this occasion was CGM use. We see that CGM use is essentially polarised between Dexcom, taking around 67% of all CGM data sources, while Abbott’s Freestyle Libre takes 30%, which has implications for people understanding CGM hygiene and safety

What’s perhaps more interesting is that more than 50% of the userbase is using either Spike or xDrip to drive their CGM, suggesting that people see benefits from the DIY solutions for use with Dexcom, over and above what the official apps offer.

Finally, the majority of responses said that they had received a positive response from their clinic, with roughly 74% of responses saying their clinic had been at least supportive. Fortunately, fewer than 2% of clinics had reacted badly.

Overall then, we see a significant jump in the numbers using DIY Hybrid Closed Loop systems in the UK, and a momentum that doesn’t seem to be slowing, which appears to be supported by the clinics that these users attend.

Age and Sex of the users

Starting with a quick look at the user base, we see that there is representation across all age groups, with people from the age of 3 to 70 using DIY systems, and a slight skew towards men.


What’s notable about this is that the largest proportion is those aged 30-50, which makes up roughly half of the population looping. There is also a concentration in the 0-15 age group, suggesting that parents are putting children on DIY looping systems for various reasons.

If we look at the split by age and sex, we see that there is not a vast amount of change in the distribution:

The key take away here is that people of all ages and sexes are using the systems to try and get better results.

System type and pump choice

Moving on to what’s in use across the UK, as we’ve seen before, AndroidAPS, Loop and OpenAPS are the systems. At a high level, we can see that AndroidAPS has increased it’s presence, going up from 54% to 66% of systems in use. 

Whilst these are the systems in use, what’s interesting is that there is a 1% other user, which isn’t clear as to what it is.

If we break this out by system type, we get a slightly different picture:


The breakout of male:female is more or less consistent with the overall proportions, however, Loop is has a bias of use in women while OpenAPS was strongly used by men compared to women. Taking that a step further and adding age in, we get this view:

This suggests that among younger teenagers, phone choice is more important (perhaps unsurprisingly) than APS system. Overall, it presents an interesting view of the population of users and their system choice.

Moving on to the pumps chosen, there is now a wider range in use, reflecting the progress in being able to use more pumps with both AndroidAPS and Loop.

What stands out most is that Accuchek pumps now account for 38% of pumps in use, only marginally different from the 36% in September, while Dana pumps now account for 25%, up from 14%, showing the increase in availability of DanaRS at UK clinics. The proportion of users of Medtronic loopable pumps has dropped dramatically from 41% to 22%, while Omnipod has increased from 3.6% to 12%.

When we look at this by system, we can see that the Omnipod has taken a phenomenal share of Loop users, after only a month of being available.

The other area where the proportions have dropped off is those using non-loopable pumps, which has gone from 9.6% to 3%, showing that a greater proportion of people are running with closed loops compared to open loops.  

Compared to September, this is almost a halving of the proportion using systems in open loop.

CGM use with DIY APS systems

In this iteration of the survey, we asked about CGM use for the first time. This was in response to some of the reported events relating to use of DIY technologies. Overall, a wide range of CGM systems are in use.

AS the chart shows, the Dexcom G6 is the favourite data source amongst UK DIY users, with the Libre with some form of adapter coming second. Overall (with 67% of the responses) Dexcom systems are favoured for the data source.

When we move on to the software in use, though, the data reflects a different story. 

64% of users are using one of the DIY CGM collection software options, with more than half electing to use xDrip. Only a third are using a version of the Dexcom official app, which, given the predominance of Dexcom offerings as the data source, is very telling. 

If we break this down by DIY system and Data source, we find that it doesn’t really matter about the system, the source data is generally preferred to come from Dexcom systems.

When we look into the software in use by system, as expected, xDrip plays little part in Loop systems, and Loop users generally are more likely to use the official Dexcom app.

The other area where choice of software is of interest is with the Dexcom source offerings. With Libre, there is no choice but to use the WeAreNotWaiting apps, however this is not a requirement if you want to use AndroidAPS or OpenAPS (although they make offline use signficantly easier)


What’s clear from these two charts is that more people use G6 on Loop (given the significantly greater use of the official Dexcom app on G6) and that with G5, people prefer xDrip, which is perhaps unsurprising given the price plans and lifespan of the G5 compared to the G6. 

Clinic Responses to DIY Closed Loop Systems

This area was also an addition for this version of the survey. Amongst respondents, most found that their clinics were supportive or very supportive of them using a DIY closed loop system (well done NHS teams!), however, there were very few areas where clinics were unsupportive.

As can be seen here, 76% were supportive of the use of DIY systems, while 90% were not unsupportive. The only area where a negative response as received was in Bristol. 9% of users had not yet told their clinic what they are doing.

Location of users

Users are located across the UK, with hotspots in London, Derby/Nottingham, Liverpool and Manchester.

These locations are unsurprising as they are either areas within the reach of local, regular build groups and also known supportive clinics.


The obvious result from the survey is that the number of users of DIY hybrid closed loop systems has almost doubled, which is likely to reflect a significant increase across the UK population of T1Ds. This is reflected in the growth in the number of members of the Looped UK facebook group, which has risen from 417 members at the end of September 2018 to 1,121 members at the end of May 2019.

We can also see that the majority of users in the UK use AndroidAPS, which is likely to be due to pump availability for use with closed loop systems. What’s clear is that the addition of the DanaRS to multiple clinics has driven a significant growth in the use of this platform. What’s also clear is that it is in use by people of all ages, and that for the most part, users are split relatively evenly by sex, with the one anomaly being OpenAPS, where the majority of users are very clearly male (although this is a small proportion of the overall userbase). As an adjunct to this, we also see that the number of people looping with Omnipod using Loop makes up almost half the respondents, with it only having been available for around a month. This is a phenomenal growth rate and reflects what has been seen globally.

Looking at the age of the users, 21% of users are under 16, while the most predominant user group is aged between 32 and 47, accounting for 45% of the users. The large proportion of children demonstrates that parents are looking to do the best that they can to provide their children with the best possible care, and potentially raises some interesting questions for paediatric diabetes services.

Looking at the use of CGM with these systems, it’s very clear that Dexcom’s G6 is the outright winner, with far more people electing to use this than any of the others, although the Libre does make up a third of users. This demonstrates that the demographic of users is either reasonably wealthy, in that they can afford to run with the G6 (which at £159 per month on subscription is not the cheapest option) or that they are in a position (paediatrics or hypo unaware) where the G6 is available funded. 

What’s perhaps more notable when looking at the CGM choices is how many are using the xDrip or Spike apps over official apps. While this is necessary for using Libre or Eversense in one of these systems, that 74% of people prefer to use xDrip over a patched version of the Dexcom app that transmits data to AndroidAPS tells you that there is a high level of preference for the flexibility that xDrip provides, and potentially offers a clear template of what people are looking for in CGM apps. It also suggests that users are still looking to eke the maximum possible life out of CGM systems to keep costs as low as they can.

Looking at the data related to clinic reactions, it is overwhelmingly positive, which is a very welcome result. From this it would appear that clinics are embracing users telling them about using DIY loops and are focusing on the outcomes obtained over whether or not the system is approved. This is a very encouraging sign. 

We can also see that the users of DIY systems are widely distributed across the UK, with hotspots that map to locations close to regular meetups and build workshops, or clinics that are known to support DIY, notably London, Nottingham & Derby, and Manchester & Liverpool. 

The significant growth that is being seen in the DIY userbase raises questions as to how much people understand about the DIY movement. Whilst it was limited to the older, more inaccessible MEdtronic pumps, there was a level of engagement required to get started, mainly focusing on getting hold of a pump. As newer, more up to date pumps that are available on the NHS come in to play, questions arise as to how well new users understand how the community has worked and whether this presents challenges to the stalwarts of WeAreNotWaiting. As a result, Dana Lewis’ new book relating to giving guidance to potential users and events like Living with Looping have been introduced to help newcomers understand everything a little better.


Overall, the use of DIY hybrid closed loops in the UK is clearly growing and the introduction of Omnipod as an option makes it more attractive to more people. There is a wide range of users of all ages, using multiple systems. 

Pump choice still appears to drive which system people use, although preferred phone operating system is also able to play a part in this decision with the Omnipod availability on the iOS platform.

With the growth in users, more work is required from long term participants in order to help those new to the concept, and various steps have been undertaken to achieve this.

The use of DIY systems is not going away, and until solutions are available on the NHS that meet users needs to almost the same level as the DIY systems do, we expect to see the growth in user numbers continue.

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