Table 2.

Summary of study outcomes

Study	Sample size n = xx Mean age	Educational level	Intervention	Effect on outcome	Other findings
Primary outcome
Effect on enrolment
Bobb 2016 [45]	n = 131 Mean age = 55	Not assessed	Telemedicine	No improvement. Computer-enabled audio-visual communication as an aid to paper consent vs written IC: 56% vs. 69%, p = 0.142
Jolly 2019 [47]	N = 4214 Mean age = 70	No formal education	Standard printed material with access to multimedia information resource	No improvement. Written IC with access to multimedia resource vs written IC: OR 0.84, 95% CI 0.58 to 1.22
Mattock 2020 [43]	N = 107 Mean parent age = 33.59 Mean child age = 21.9 months	47% educated at postgraduate level	Information video as an aid to patient information sheet	Intervention group less likely to take part in main clinical trial. Video aid to paper v written IC: OR = 0.25, CI = 0.10–0.62, p = 0.003
Swain 2017 [49]	N = 200 Mean age = 59	29% attended some college or technical school	Educational video	Improvement on enrolment by 7% post-intervention (13.5% of 200 participants enrolled post-intervention, 6% enrolled pre-intervention, p < 0.001)
Weston 1997 [50]	N = 90 Median age = 31.4	40–42% achieved college degree or higher	Information video	Improvement on participants expressing willingness to participate in a future trial (61.9% vs. 35.4%, χ2 = 6.3; df = 1; p = 0.01)
Secondary outcomes
Effect on economic costs
Afolabi 2015 [39]	N = 311 Mean age = NA	> 50% no formal education	Video information	No results available
Jolly 2019 [47]	N = 4214 Mean age = 70	No formal education	Standard printed material with access to multimedia information resource	Additional six people would be recruited per 1000 approached at a cost of £100 per additional patient with the use of an online multimedia intervention. The cost of the online multimedia intervention was estimated £2500
Patient comprehension and understanding
Afolabi 2015 [39]	N = 311 Mean age = NA	> 50% no formal education	Video information	Improvement. Score at day 14: 64%v 40%, p = 0.035
Barrera 2016 [40]	N = 1179 Mean age = 27.6	81.5% University level	Online IC	Improvement. Correct understanding of the study’s purpose (86.1%) and correctly identified two of three of the study’s benefits (74.6%). 56% correctly identified some or all of the potential risks of participation	Qualitative interviews in this study supported that the video was easy to understand and improved participants’ attention
Bobb 2016 [45]	N = 131 Mean age = 55	Not assessed	Telemedicine	Not inferior to standard face-to-face written consent, measured using a modified quality of informed consent instrument (QuIC) (QuIC scores 74.4 ± 8.1 vs. 74.4 ± 6.9 on a 100-point scale, p = 0.999)
Ditai 2018 [41]	N = 30 Mean age = NA	50% no formal education	Slide show using illustrated text on a flip chart	No statistically significant difference on the QuIC tool at 48 h after consenting to any of the three models of IC	Most participants preferred the slide-show message (63%, 19/30), compared with 20% (6/30) for the video message and 17% (5/30) for the standard model
Rothwell 2014 [44]	N = 62 Mean age = NA	41.94% bachelor’s degree	Video	Improve understanding of some aspects of a trial: “the alternatives to participation in this study” (4.88 ± 0.42 vs. 4.37 ± 1.10, p = .047); “who to contact if you are upset because of participation in this study” (4.41 ± 0.80 vs. 4.03 ± 1.40, p = .002); “Whom you should contact if you have questions or concerns about this study” (4.34 ± 0.97 vs. 4.13 ± 1.33, p = .009); and “Overall, how well did you understand this study when you signed the consent form” (4.72 ± 0.58 vs. 4.63 ± 0.67, p = .019)	Comprehension not inferior to standard face-to-face written consent (QuIC scores 74.4 ± 8.1 vs. 74.4 ± 6.9 on a 100-point scale, p = 0.999)
Weston 1997 [50]	N = 90 Median age = 31.4	40–42% achieved college degree or higher	Information video	No differences in knowledge about the perinatal trial after receiving a video intervention when compared to written IC but they did find an increase in the retention of knowledge 2–4 weeks later by women in the video intervention group
Acceptability to participants
Mattock 2020 [43]	N = 107 Mean parent age = 33.59 Mean child age = 21.9 months	47% educated at postgraduate level	Information video as an aid to patient information sheet	Positive feedback. Information easy to understand and informative but also commented on additional questions that needed discussing over the phone	Participants in the video group described material as introductory whilst those in standard consent group described the standard information as comprehensive. Participants and researchers found that an initial email contact increased participant’s receptivity to the study and engagement in the trial. Researchers also reported a better understanding of randomization by participants who watched the video
Haussen 2017 [42]	N = 4 Mean age = 73	Not assessed	All 3 components electronic for DAWN trial. Method for ARISE-I presumed the same	Acceptability of the use of an entirely electronic IC process to remotely obtain IC from the legally authorized representative (LAR) of stroke patients being enrolled into a clinical trial of neurointervention
Bobb 2016 [45]	N = 131 Mean age = 55	Not assessed	Telemedicine	No significant barriers in the use of telemedicine (computer-enabled audio-visual communication) as an aid to paper consent from its qualitative survey. It reported that video was easy to understand and was better at holding patient’s attention than a paper-based approach would have
Changes in treatment preferences
Lurie 2011 [48]	N = 2505 Mean age = IDH 41.2, SPS 65.1	No difference in education attainment	Video as an aid to the IC	Watching video information prior to enrollment to a clinical trial comparing surgical and non-surgical treatments for spinal diseases led to a shift in treatment preference compared to non-watchers (37.9% vs 20.8%, p < 0.0001)
Invitation response and retention
Jolly 2019 [47]	N = 4214 Mean age = 70	No formal education	Standard printed material with access to multimedia information resource	No effect on the proportion of people responding to study invitation (OR = 1.02, 95% CI 0.79 to 1.33) or retention in the trial at 6 (ORs 0.84, 95% CI 0.57 to 1.22) and 12 months after randomization
Swain 2017 [49]	N = 200 Mean age = 59	29% attended some college or technical school	Educational video	Increase by 14% (p < .001) in the proportion of patients expressing likelihood to enroll in a trial for breast cancer after the use of an educational video
Intervention fidelity
Jolly 2019 [47]	N = 4214 Mean age = 70	No formal education	Standard printed material with access to multimedia information resource	Number of participants who used the link to access the multimedia resource which was part of the intervention was not reported, so it was unclear how many participants actually used the resource
Mattock 2020 [43]	N = 107 Mean parent age = 33.59 Mean child age = 21.9 months	47% educated at postgraduate level	Information video as an aid to patient information sheet	Utilized an entire remote e-IC process to obtain IC from LAR. However, it was not possible to ascertain whether the LAR actually read the online IC. It was unclear how much time the LARs or patients were given to decide about trial participation