Table 2.

Final codebook template including deductively (A-D) and inductively (A1-D2) developed codes.

Topic		Occurrencesa, n	Illustrative quote	Respondent profile
Emotional and quality of life impact (A)
	Worry and fear (A1): describes difficult emotions such as worry and fear of caregivers related to living with and managing diabetes, experiencing hypoglycemia, and developing long-term complications. It also refers to the concern of not being able to build and maintain the open-source AIDb.	16	“I was very skeptical and scared. Over time more information became available and the safety became clear and compelling. We realized we would be safer with a Loop than without. I was scared that others would not be able to comprehend this (because even endocrinologists fail to understand fully the burden and dynamism of type 1) and that they would question whether we were putting our child at risk and make a report about us to child well-being authorities.”	Caregiver of a boy aged 13 years, from Australia; aged 6 years at diagnosis; using Loop for 2.5 years
	Desperation and frustration (A2): describes feelings of desperation and frustration of caregivers related to living with diabetes and caring for a child with diabetes, diabetes management, and the implementation of the open-source AID.	14	“As a mom I was desperate, I was tired from being up all night, I was getting frustrated from teen hormones and I was willing to try almost anything to help both of us.”	Caregiver of a girl aged 17 years, from the United States; aged 2 years at diagnosis; using Loop for 33 months
	Uncertainty (A3): describes uncertainty and insecurities of caregivers regarding legal grounds, missing regulatory guidelines, and the trust of reliability in an open-source AID system.	6	“Nevertheless, there is still a legal uncertainty and at the moment we just dare to use the loop in our own four walls. In the morning we switch to the normal AnyDana A app, in the evening back to AndroidAPS.”	Caregiver of a boy aged 12 years, from Germany; aged 11 years at diagnosis; using OpenAPS for 2 weeks
	Anticipation, hope, and wishes (A4): describes positive and hopeful emotional states of anticipation and great expectations of caregivers that lie on the AID for improved diabetes management and hope for improved quality of life. Also includes wishes for access to an AID system for everyone.	24	“Major driver for the project was to give my son more years without complications by lowering the HbA1cc.”	Caregiver of a boy aged 18 years, from Finland; aged 1 year at diagnosis; using OpenAPS for 1 year
	Excitement, appreciation, and satisfaction (A5): describes all positive emotions of caregivers and children related to the experience with the open-source AID in daily use including excitement, happiness, satisfaction with the results, and appreciation.	51	“I remember the exact place I stood watching the [OpenAPS] log [roll] and seeing the [preflight] was successful and then that the loop was complete. I was in shock that we could do this and that I could afford it and that my child was going to [be] better off because of this. It was a defining moment in my life as a parent. No one could stop me giving my child the care they needed anymore. Especially not a company who places shareholders above clients (which legally they must do). I was no longer at the mercy of markets, profits, politics and whims, I had the capacity to provide for my child again.”	Caregiver of a boy aged 13 years, from Australia; aged 6 years at diagnosis; using Loop for 2.5 years
	Security and reassurance (A6): relates to caregivers feeling more empowered, more secure, and reassured owing to the use of an open-source AID system, through automation, remote monitoring, and control, as well as experiencing success and observing the success of others using an open-source AID.	45	“Our child never woke up if she had a low even though her pump was sounding a very loud alarm. And because she slept in her own room we were afraid of sometimes not hearing the pump alarm either. So Nightscout sounded like the perfect solution, as we could then be woken up by any mobile phone or iPad. This added a lot to our feeling of security.”	Caregiver of a girl aged 10 years, from Finland; aged 7 years at diagnosis; using OpenAPS for 3 months
	Child empowerment and independence (A7): describes the degree of independence, autonomy, and self-determination in children and adolescents using the open-source AID, enabling them to participate in daily life and social activities in a responsible and self-determined way.	25	“Daughter can work without having to phone me for advice. She has been on holiday [for the] first time without parents. She[...] now feels confident to consider leaving home.”	Caregiver of a girl aged 20 years, from Croatia; aged 10 years at diagnosis; using OpenAPS for 3 months
Physical health impact (B)
	Glycemic outcome improvement (B1): refers to improved time in range and HbA1c levels, less glucose variability, fewer hypo- and hyperglycemic events, and reduced long-term complication risk.	36	“Every single morning she’s in range. If at night she’s not, we know that by the morning she will be, and she [will get] there safely. It’s really good.”	Caregiver of a girl aged 18 years, from the United Kingdom; aged 11 years at diagnosis; using AndroidAPS for 8 months
	Quality of life improvement (B2): refers to the mentioned improvements of quality of life and describes the degree to which an individual is healthy, comfortable, and able to participate in or enjoy life events.	14	“I keep a continuous discussion with my twins that both use DIY closed loops, through texting. I use this way to share my remote observations on their status, while they concentrate on their university studies, or simply enjoy their lives. I inform them this way about a failing connection, a reservoir getting empty, a battery needing charging, or to drink some juice to avoid a coming low.”	Caregiver of a boy, aged 20 years, from Greece; aged 2 years at diagnosis; using OpenAPS for 1 year
	Improved sleep (B3): denotes all aspects of improved sleep quality for either caregivers or children such as increased sleep duration, fewer sleep interruptions, and feeling better rested in the morning.	40	“It’s been as good as expected, and better still as now we sleep. You forget how much sleep deprivation clouds your judgment.”	Caregiver of a boy aged 8 years, from the United Kingdom; aged 7 years at diagnosis; using AndroidAPS for 3 months
	Facilitated diabetes management (B4): relates to the simplifications of the individual diabetes management due to the open-source AID, such as fewer interactions with the technology or between caregiver and child; for example, through remote control and automation. It also includes the age-appropriate transfer of responsibilities from caregivers to adolescents to self-manage diabetes therapy.	42	“There is no comparison with earlier. There used to be 5-6 blood measurements per child per day, and that was all. With or without a pump, every meal was a challenge. For 1.5 years, the APS has been adjusting the blood sugar value after the bolus, adding more insulin if the value increases, or adjusting the delivery if the value drops.”	Caregiver of a boy aged 20 years, from Greece; aged 1 year at diagnosis; using OpenAPS for 17 months
Challenges (C)
	Access to technology (C1): relates to the issue concerning obtaining access to the component parts of an open-source AID system, such as loopable pumps and supplies, CGMd, and additional required hardware.	27	“Getting the hardware was most frustrating. I tried to buy the hardware from the manufacturer but in Sweden you could not do that without a subscription from your doctor. I ended up getting a second hand Dana R pump from another patient who upgraded to a newer pump.”	Caregiver of a boy aged 3.5 years, from Sweden; aged 2 years at diagnosis; using AndroidAPS for 4 months
	Out-of-pocket expenses (C2): describes barriers regarding out-of-pocket expenses and cost for the hardware and supplies related to insurance coverage, household income, and other financial challenges in access.	6	“We were concerned about the cost of sensors. They are not covered by private health here and it cost approximately US $5000 a year when we started. Now kids are covered, but when they turn 21 that ends. We are still worried about covering that bill in the future.”	Caregiver of a boy aged 13 years, from Australia; aged 6 years at diagnosis; using Loop for 2.5 years
	Self-perceived lack of technical skills (C3): denotes the issue of yet self-perceived limited knowledge and missing technical skills caregivers are experiencing to set up open-source AID initially.	9	“Major fears I wouldn't be able to understand the technology.”	Caregiver of a girl aged 12 years, from Australia; aged 11 years at diagnosis; using Loop for 1 month
	Lacking health care provider support (C4): relates to instances where caregivers reflect upon their children’s health care providers’ lack of support and negative attitudes.	14	“Fight with our own diabetologist to get a DANA RS prescribed. Although we didn’t talk openly about looping, she has repeatedly emphasized that we only want the DANA RS pump for looping, which is not allowed. We have won, but now hide the loop, which cannot be a permanent state. We need medical care in which we can communicate openly.”	Caregiver of a boy aged 12 years, from Germany; aged 11 years at diagnosis; using AndroidAPS for 2 weeks
	Impracticability of carrying additional devices (C5): relates to the necessity for children and adolescents having to carry additional devices for open-source AID and protect them from breaking.	9	“It also meant that our daughter had to carry an extra item, i.e. the mini-computer, with her during the day.”	Caregiver of a girl aged 10 years, from Finland; aged 4 years at diagnosis; using OpenAPS for 2 months
	Transition from childhood to adulthood (C6): describes challenges associated with the transition from childhood to adulthood, regarding physical and hormone-related changes during puberty and psychosocial challenges in adolescents living with T1De and taking over responsibility for their own therapy with an open-source AID.	10	“While our control has improved, it is still significantly more variable than I would expect based on the results I see from others in the community. My son is highly insulin sensitive [...], variable in his activity level and intensity [...], and experiencing substantial swings in carb ratios, basal rates, and insulin sensitivities as he is going through great physiological changes in puberty.”	Caregiver of a boy aged 11 years, from the United States; aged 8 years at diagnosis; using OpenAPS for 1 year
	Setup and maintenance effort (C7): relates to difficulties caregivers experience while setting up open-source AID. This includes an unexpected high time effort and multiple throwbacks while initially setting up the system, technical difficulties with running and maintaining the system, and fine-tuning to find the right settings and parameters to accomplish desired results.	54	“As a family, we feel very happy that we can finally control the blood sugar levels of our children in the desired area, even if it takes great care to do everything right. Batteries (pump, CGM, mobile phone, OpenAPS computer) must be regularly charged or exchanged, the CGM must be continuously calibrated, insulin must be refilled, every 3 days you exchange the catheter, every 14 days the CGM, etc. With such a result, no problem. The hundreds of hours I've spent on it are worth it.”	Caregiver of a boy aged 20 years, from Greece; aged 1 year at diagnosis; using OpenAPS for 17 months
Support (D)
	Community peer support (D1): includes actively received or provided community peer support. This support could either be provided on the web through social media groups and communities or in person through life events, individual people, or meet-ups. Does not include individual key people or role models.	45	“So in that same Facebook group I started to learn about DIY artificial pa[n]creases and I joined another, international group called Looped to learn more. I then asked around and I was told that OpenAPS was the most advanced of the three options and decided to go for that.”	Caregiver of a girl aged 10 years, from Finland; aged 7 years at diagnosis; using OpenAPS for 9 months
	Individuals as role models (D2): describes one or multiple key people, often members of the #WeAreNotWaiting community, who inspired or directly supported caregivers and children in building an open-source AID.	15	“I found Tim Street’s Diabettech website and started following him on twitter/blog at [the] same time. He was coming to speak at a medical conference in Edinburgh and was going to a [type 1] meet up. I gate-crashed the meet in the pub and had to wait until the end[...] I asked him to show me his pancreas! [...] Tim organized the first U.K. meet up in London and offered me an old transmitter which would complete my build. My son and I flew to London and we got going that evening.”	Caregiver of a boy aged 12 years, from the United Kingdom; aged 8 years at diagnosis; using OpenAPS
	Web-based resources (D3): describes web-based resources such as wiki blogs, tutorials, websites, webinars, and other documentation.	19	“Once I had the equipment, I set the system up in two nights, the instructions available on the web are very clear and I found it easier tha[n] expected.”	Caregiver of a girl aged 10 years, from Finland aged 6 years at diagnosis; using OpenAPS for 3 months
	Health care professionals (D4): this code refers to the support provided by health care professionals, such as pediatricians, endocrinologists, and other members of the diabetes teams, including help with setup, access to components, and fine-tuning of settings.	8	“Endocrinologist was supportive even though legally couldn’t recommend it.”	Caregiver of a girl aged 12 years, from Australia; aged 11 years at diagnosis; using Loop for 1 month

^aDefined by the number of codes assigned to a text segment.

^bAID: automated insulin delivery.

^cHbA_1c: hemoglobin A_1c.

^dCGM: continuous glucose monitor.

^eT1D: type 1 diabetes.