Table 3 Key informant interview themes

Knowledge of study procedures/objectives

“I was under the impression that [the study pertained to] blood clots because I was going in for surgery and had a prior history of blood clots … so it was basically no big deal” (P9)

“I recall the self-injection, and some would be placebo and some would be the real thing [heparin].” (P12)

“I thought it was pretty clear” (P17)

“At one point I thought that the study was 3 months long and that really gave me a little bit of anxiety and I was going to quit, but once I found out the actual time reference (30 days) I had no problem continuing” (P8)

“I thought a nurse would be coming out [to my home] to do [the injection] for me, and they said no that’s not the way it works. I was waiting for the nurse to come. I didn’t realize it was going to entail self-injections” (P10)

“I don’t drive, I don’t have a car and I am 88 years old, and I just couldn’t be bothered to [go back and forth to hospital]”

Interviewer: So was it your impression that you had to go to hospital to receive the injection for 30 days?

“Yes” (P11)

Support from family/friends

“My wife agreed with me that it [VTE-PRO participation] was probably a good idea she gave me a couple of injections … my wife was 100% involved … I think it was quite important that there is somebody there for the person” (P3)

“My husband is always supporting me in everything … but yeah, maybe other people might want more people involved”

“It might irritate some people [if family was involved], and they might think oh yeah that was a good idea if I had my family and my friends to remind me, and then get a phone call and be overwhelmed.” (P6)

“I don’t have very supportive friends. They were like ‘what, you signed up for this?’ and I was like, ‘yeah, it’s all volunteer’.”

“The time I didn’t do my injection, it wasn’t that I forgot, I think it was kind of laziness on my part. You know what I mean, like to get out of bed and actually do this … and I said I am going to stay right here in bed” (P7)

Reminders to take injection

“[My wife and I] reminded each other really. It was basically around 12 noon every day that we did the injection” (P13)

“My family was supportive, my wife was an alarm clock [reminder]”

“There were two successive days that for some reason I forgot [to take the injection]” (P17)

“A couple times if my husband hadn’t asked me if I had done it [the injection] then I would have forgotten to do it. There was one day that I completely forgot, and I didn’t remember until the next day” (P8)

Ability to self-administer injection

“It was not hard or anything, it was a small needle and you just stick it in your stomach and it was all good” ((P2)

“They are not big needles and they are not a big deal and they don’t go deep … it”

“I had my granddaughter coming over at seven in the morning to get the injection to me and then … a week and a half later I started doing them myself” (P7)

“I am worried I am going to fill the syringe incorrectly … you know pulling the plunger out and getting the air out … I’m not going to self-inflict this worry” (P10)

“A lot of people are afraid of needles … trying to get them to give one to themselves would be hard” (P9)