Appendix 1.Questionnaire items categorised by theme and subcategory a

Theme b / Sub-theme b (if applicable) / Barriers to Insulin Treatment Questionnaire (BIT) [46] / Insulin Treatment Appraisal scale (ITAS) [47] / Study the Hurdles of Insulin Prescription (SHIP) [38]c / Beliefs about Insulin Scale (BIS) [50]d / Chinese Attitudes to Starting Insulin Questionnaire (Ch-ASIQ) [48]
Disease severity implications / N/A / 2 "Taking insulin means my diabetes has become much worse." / 8 "Upset because diabetes is getting worse.” / 4 "If I had to take insulin, it would mean that I'm in the last stage of this illness."
Diabetes stigma / Self-blame / 1 "Taking insulin means I have failed to manage my diabetes with diet and tablets." / 16 "If I had to take insulin, it would only be my fault."
Impaired self-evaluation / 5 "If I have to take insulin it would mean that I am a weak person."
9 "Having an insulin treatment wouldn’t make me inferior to others." *
13 "If I have to take insulin, I would be less of a person than others."
17 "I would be just as valuable as others if I had to take insulin." *
Embarrassment / 10 "Injections in public are embarrassing to me. Pills are more discreet." / 13 "Injecting insulin is embarrassing." / 11 "Bothered by being seen while injecting." / 1 "I worry that people will know I have diabetes if I am on insulin treatment."
12 “Fear that people notice I'm diabetic." / 2 "Injecting insulin is embarrassing, I worry about being seen when I inject insulin."
Perceived as sicker / 4 "Taking insulin means other people see me as a sicker person".
18 “Being on insulin causes family and friends to be more concerned about me."
Associated with illicit drug use / 12 "When people inject insulin, it makes them feel like drug addicts." / 3 "If I have to inject insulin, it makes me feel like a drug addict."
Injection-related anxieties / Fear of injections or pain / 1 "I am afraid of the pain when injecting insulin." / 6 "I’m afraid of injecting myself with a needle." / 14 "Stressed because injection can be painful." / 18 " I couldn’t stage injecting myself insulin." / 9 "Injecting insulin is painful."
2 "Besides the pain, I am just afraid of injections." / 14 "Injecting insulin is painful." / 10 "I am afraid of needle injections."
Fear / anticipated pain of glucose monitoring / 3 "I am afraid of the pain during regular blood-sugar checks." / 11 "I worry about needing to perform home blood sugar monitoring"
Self-efficacy (as a barrier or facilitator) / N/A / 8 "I can’t pay as close attention to my diet as insulin treatment requires." / 15 "It is difficult to inject the right amount of insulin correctly at the right time every day." / 3 "Favourable because of easiness of treatment." * / 7 "It would be hard to inject myself with insulin, but I could manage." * / 4 "I have up-to date knowledge about diabetes management.” *
9 "I can’t organize my day as carefully as insulin treatment requires." / 10 "Fear that treatment gets more complicated." / 11 "It would be unfortunate to take insulin but I could bare it." * / 6 "I can manage the skill of injecting insulin." *
8 "I can pay as close attention to my diet as my insulin treatment requires. For example, I may need to take a snack or reduce my eating amount appropriately." *
Concern about adverse effects / Weight gain / 9 "Insulin causes weight gain."
Hypoglycaemia / 13 "An insulin overdose can lead to extremely low blood-sugar levels ("hypoglycemia"). I am afraid of the unpleasant accompanying symptoms." / 7 "Taking insulin increases the risk of low blood glucose levels (hypoglycemia)." / 9 "Fear of having more hypoglycemia crises."
14 "An insulin overdose can lead to extremely low blood-sugar levels ("hypoglycemia"). I have concerns about possible permanent damage to my health."
Scarring / 13 "Bothered by skin being marked at injection site."
Insulin causes complications / 12 "Taking insulin means my health will deteriorate." / 19 "If I took insulin, I could become blind or require amputation.”
8 "If I started an insulin treatment only bad things will follow for me."
22 "I feel that insulin treatment would only bring more problems."
Impact on daily flexibility and independence / N/A / 7 "I just don’t have enough time for regular doses of insulin." / 5 "Taking insulin makes life less flexible." / 2. "Happy because of improvement in quality of living." * / 12 "I can spare enough time to perform insulin injections." *
11 "Regular insulin treatment causes feelings of dependence." / 10 "Managing insulin injections takes a lot of time and energy." / 4 "Advantage because of less restricted diet." *
11 "Taking insulin means I have to give up activities I enjoy." / 6 "Feeling restricted because of self-surveillance.”
16 "Taking insulin makes it more difficult to fulfil my responsibilities (at work, at home)." / 7 "Constraint because dependency, liberty loss."
20 "Taking insulin makes me more dependent
on my doctor."
Treatment efficacy / N/A / 4 "Insulin works better than pills." / 3 "Taking insulin helps to prevent complications of diabetes." * / 1 "Willingness because of more balance diabetes." * / 5 "Insulin can help control blood glucose and prevent complications." *
5 "People who get insulin feel better." / 8"Taking insulin helps to improve my health." *
6 "Insulin can reliably prevent long-term complications due to diabetes." / 17 "Taking insulin helps to maintain good
control of blood glucose." *
19 "Taking insulin helps to improve my energy level." *
Support from others / Social support / 7 "There is social support available if I have to inject insulin." *
13 "My family will support me to inject insulin." *
Healthcare support / 5" Confidence in physicians." *
General negative emotional reaction to insulin / N/A / 1 "I should never have to take insulin, even if doctor recommend it to me.”
2 "I believe that insulin is not the worst thing." *
3 "I can't stand the idea of taking insulin.”
6 "There would be nothing worse than taking insulin."
10 "I wish I didn't need insulin but I know that things don't always happen the way I want them to." *
12 "Even if my blood glucose were good, taking insulin would still be terrible."
14 "I must not take insulin even if my doctor said so."
15 "I do not wish to have insulin treatment, but I think there could be much worse situations than this treatment."*
19 "I prefer not taking insulin but I know that this is not something I can control by wishing it."*
21 "Taking insulin would be awful."
a Item wording based on that published in original validation studies.
b Themes and sub-themes have been proposed by the authors of this review paper based upon the item wording as published in original validation studies and drawing from themes identified in qualitative studies [15-17]. These do not represent a fully validated coding structure.
c The SHIP is not currently available in English, so the wording in this table refers to the published English summary of the items[38], and is not a valid translation of the actual item wording.
d The BIS questionnaire has been published in English (as cited above), but has not undergone linguistic or psychometric validation in English.
* Items are positively framed.