A Web-Based Acceptance-Facilitating Intervention for Identifying Patients’ Acceptance, Uptake, and Adherence of Internet- and Mobile-Based Pain Interventions: Randomized Controlled Trial

Background Internet- and mobile-based interventions are effective for the treatment of chronic pain. However, little is known about patients’ willingness to engage with these types of interventions and how the uptake of such interventions can be improved. Objective The aim of this study was to identify people’s acceptance, uptake, and adherence (primary outcomes) with regard to an internet- and mobile-based intervention for chronic pain and the influence of an information video as an acceptance-facilitating intervention (AFI). Methods In this randomized controlled trial with a parallel design, we invited 489 individuals with chronic pain to participate in a Web-based survey assessing the acceptance of internet- and mobile-based interventions with the offer to receive an unguided internet- and mobile-based intervention for chronic pain after completion. Two versions of the Web-based survey (with and without AFI) were randomly sent to two groups: one with AFI (n=245) and one without AFI (n=244). Participants who completed the Web-based survey with or without AFI entered the intervention group or the control group, respectively. In the survey, the individuals’ acceptance of pain interventions, measured with a 4-item scale (sum score ranging from 4 to 20), predictors of acceptance, sociodemographic and pain-related variables, and physical and emotional functioning were assessed. Uptake rates (log in to the intervention) and adherence (number of completed modules) to the intervention was assessed 4 months after intervention access. To examine which factors influence acceptance, uptake rate, and adherence in the internet- and mobile-based interventions, we conducted additional exploratory subgroup analyses. Results In total, 57 (intervention group) and 58 (control group) participants in each group completed the survey and were included in the analyses. The groups did not differ with regard to acceptance, uptake rate, or adherence (P=.64, P=.56, P=.75, respectively). Most participants reported moderate (68/115, 59.1%) to high (36/115, 31.3%) acceptance, with 9.6% (11/115) showing low acceptance (intervention group: mean 13.91, SD 3.47; control group: mean 13.61, SD 3.50). Further, 67% (38/57, intervention group) and 62% (36/58, control group) had logged into the intervention. In both groups, an average of 1.04 (SD 1.51) and 1.14 (SD 1.90) modules were completed, respectively. Conclusions The informational video was not effective with regard to acceptance, uptake rate, or adherence. Despite the high acceptance, the uptake rate was only moderate and adherence was remarkably low. This study shows that acceptance can be much higher in a sample participating in an internet- and mobile-based intervention efficacy trial than in the target population in routine health care settings. Thus, future research should focus not only on acceptance and uptake facilitating interventions but also on ways to influence adherence. Further research should be conducted within routine health care settings with more representative samples of the target population. Trial Registration German Clinical Trial Registration DRKS00006183; http://www.drks.de/drks_web/navigate.do ?navigationId=trial.HTML&TRIAL_ID=DRKS00006183 (Archived by WebCite at http://www.webcitation.org/70ebHDhne)


INTRODUCTION 2a) In INTRODUCTION: Scientific background and explanation of rationale
Does your paper address subitem 1b-iii? "we invited 489 individuals with chronic pain to participate in a Web-based survey assessing the acceptance of IMIs with the offer to receive an unguided IMI for chronic pain after completion." 1b-iv) RESULTS section in abstract must contain use data Does your paper address subitem 1b-iv? "Most participants reported moderate (59%, 68/115) to high (31%, 36/115) acceptance, with 10% (11/115) showing low acceptance (IG: mean 13.91, SD 3.47; CG: mean 13.61, SD 3.50). Further, 68% (38/57, IG) and 62% (36/58,CG) had logged into the intervention. In IG and CG, an average of 1.04 (SD 1.51) and 1.14 (SD 1.90) modules were completed, respectively." 1b-v) CONCLUSIONS/DISCUSSION in abstract for negative trials Does your paper address subitem 1b-v? "The informational video was not effective with regard to acceptance, uptake rate, or adherence. Despite the high acceptance, the uptake rate was only moderate and adherence was remarkably low. This study shows that acceptance can be much higher in a sample participating in an IMI efficacy trial than in the target population in routine health care settings. Thus, future research should focus not only on acceptance and uptake facilitating interventions but also on ways to influence adherence. Further research should be conducted within routine health care settings with more representative samples of the target population." 2b) In INTRODUCTION: Specific objectives or hypotheses 2a-i) Problem and the type of system/solution Does your paper address subitem 2a-i? * "A repeatedly suggested reason for low uptake and adherence is the low level of patients' acceptance of IMIs, conceptualized as the intention to use the intervention [40][41][42]. Other factors, such as internet usage and anxiety [41,43], uncertainty con-cerning data security, discomfort with use of IMIs and psychological interventions in general, and social influence by friends, family, and health professionals as well as a lack of trust in the effectiveness of IMIs are often reported to influence the acceptance and uptake of IMIs [40,42,[44][45][46][47]. Aiming at these aspects of acceptance, acceptance facilitating interventions (AFIs) are suggested to reduce patients´ apprehensions and misconceptions about IMIs. They provide trustworthy information on, as well as an introduction to IMIs [40,[48][49][50][51]." 2a-ii) Scientific background, rationale: What is known about the (type of) system Does your paper address subitem 2a-ii? * "To date, 3 RCTs have investigated the influence of a video-based [42,47] or personal [46] AFI in the clinical population of pain [47], diabetes [46], and primary care patients with depressive symptoms [42]. All studies consistently reported low baseline acceptance and an increase in acceptance following AFI [42,46,47,52]. However, all three studies only examined patients' acceptance and lack more important information on whether AFI effectively increased intervention uptake. Only two studies have reported on the relationship between IMI acceptance and IMI usage [27,53]. In both studies, a significant association was found between IMI acceptance and usage (log-in and adherence). This finding suggests that AFIs might also influence IMI usage. However, research on the influence of an AFI on interven-tion uptake and adherence is missing." METHODS 3a) Description of trial design (such as parallel, factorial) including allocation ratio 3b) Important changes to methods after trial commencement (such as eligibility criteria), with reasons Does your paper address CONSORT subitem 2b? * "Therefore, in this study we examined whether an informational video (AFI) can increase patients' (1) acceptance of an IMI for chronic pain, (2) uptake of an IMI for chronic pain, and (3) adherence in an IMI for chronic pain.
We expected that AFI would positively increase patients' acceptance as well as the uptake rate and adherence. In addition, we expected that AFI would increase the predictors of acceptance and have a reducing effect on internet anxiety. To examine which factors influence acceptance, uptake rate, and adherence in IMIs, we conducted additional exploratory subgroup analyses." Does your paper address CONSORT subitem 3a? * "This was a two-arm pragmatic study using a parallel-group design with balanced (1:1) randomization. The intervention group (IG) received AFI with a subsequent Web-based survey (homepage provided by the University of Freiburg, Germany); the control group (CG) filled out the same Web-based survey without receiving AFI. In this RCT, randomization took place before the assessment of eligibility and inclusion of participants. We chose this procedure as it allowed us to send an invitation email providing a link to the survey in either the IG or CG condition. This is a case of randomization before data are available to confirm the individuals' eligibility without risking bias in the analysis [54]. Therefore, post-randomization exclusions of all non-eligible participants can be regarded as acceptable [54]." Does your paper address CONSORT subitem 3b? * no 3b-i) Bug fixes, Downtimes, Content Changes Does your paper address subitem 3b-i? no 4a) Eligibility criteria for participants Does your paper address CONSORT subitem 4a? * "The recruitment took place in September 2015. We sent email invitations to all individuals to participate in this study who had earlier expressed interest in participating in an evaluation study on ACTonPain [22,55]. Individuals in the following categories could not be included in the evaluation study on ACTonPain for the following reasons: (1) screening or baseline assessment not completed or no informed consent for main trial (n=332) or (2) expressed their interest in participating after the target sample size of the main trial was reached (n=157). Applicants for participation in the main trial indicating an elevated risk of suicide were not invited. We assessed the following inclusion criteria based on the Web-based self-report: (1) ≥18 years of age, (2) pain duration≥3 months, (3) sufficient German language skills, and (4) sufficient computer and internet skills to proceed with the Web-based questionnaire. We excluded all participants with an incomplete informed consent form and those not fulfilling the inclusion criteria. " 4a-i) Computer / Internet literacy Does your paper address subitem 4a-i? " (4) sufficient computer and internet skills to proceed with the Web-based questionnaire. " 4a-ii) Open vs. closed, web-based vs. face-to-face assessments: Does your paper address subitem 4a-ii? * "The intervention group (IG) received AFI with a subsequent Web-based survey (homepage provided by the University of Freiburg, Germany); the control group (CG) filled out the same Web-based survey without receiving AFI." 4b) Settings and locations where the data were collected 4a-iii) Information giving during recruitment Does your paper address subitem 4a-iii? "Reading and providing online informed consent and answering the survey took about 20-30 minutes. " Does your paper address CONSORT subitem 4b? * "We sent email invitations to all individuals to participate in this study who had earlier expressed interest in participating in an evaluation study on ACTonPain [22,55]. Individuals in the following categories could not be included in the evaluation study on ACTonPain for the following reasons: (1) screening or baseline assessment not completed or no informed consent for main trial (n=332) or (2) expressed their interest in participating after the target sample size of the main trial was reached (n=157). Applicants for participation in the main trial indicating an elevated risk of suicide were not invited." 4b-i) Report if outcomes were (self-)assessed through online questionnaires Does your paper address subitem 4b-i? * "Reading and providing online informed consent and answering the survey took about 20-30 minutes. " 4b-ii) Report how institutional affiliations are displayed 5) The interventions for each group with sufficient details to allow replication, including how and when they were actually administered Does your paper address subitem 4b-ii? "The intervention group (IG) received AFI with a subsequent Web-based survey (homepage provided by the University of Freiburg, Germany); the control group (CG) filled out the same Web-based survey without receiving AFI. " 5-i) Mention names, credential, affiliations of the developers, sponsors, and owners Does your paper address subitem 5-i? "The intervention group (IG) received AFI with a subsequent Web-based survey (homepage provided by the University of Freiburg, Germany); the control group (CG) filled out the same Web-based survey without receiving AFI. " 5-ii) Describe the history/development process Does your paper address subitem 5-ii? "AFI consisted of a 3-minute introductory and information video to ACTonPain with screenshots of the program in order to improve patients' acceptance. Figure 2 pro-vides screenshots of AFI. We designed the content of the intervention to address the aforementioned barriers and drivers of acceptance.
We conceptualized the video based on our previous AFIs that showed to be effective in increasing acceptance [42,47,65]. Our AFI is an adopted version of AFI used in a former study with individuals with chronic pain [47] with a specific introduction to ACTonPain. The content of the video comprised information on (1) the effectiveness of IMIs, (2) data security and anonymity in IMIs, (3) various advantages of IMIs (eg, ease and comfort of use, flexible time management), (4) the possibility of receiving technical support, and (5) assistance during the program. Furthermore, the video presented the process for using ACTonPain, encompassing the log-in or log-off processes and an overview of the modules and different features (audio files, video clips, and homework assignments)."

5-iii) Revisions and updating
Does your paper address subitem 5-iii? "Our AFI is an adopted version of AFI used in a former study with individuals with chronic pain [47] with a specific introduction to ACTonPain. The content of the video comprised information on (1) the effectiveness of IMIs, (2) data security and anonymity in IMIs, (3) various advantages of IMIs (eg, ease and comfort of use, flexible time management), (4) the possibility of receiving technical support, and (5) assistance during the program. Furthermore, the video presented the process for using ACTonPain, encompassing the log-in or log-off processes and an overview of the modules and different features (audio files, video clips, and homework assignments)."

5-iv) Quality assurance methods
Does your paper address subitem 5-iv? 5-v) Ensure replicability by publishing the source code, and/or providing screenshots/screen-capture video, and/or providing flowcharts of the algorithms used Does your paper address subitem 5-v? content of an online pain intervention. Screenshot 2: introduction to Acceptance and Commitment-based online treatment for chronic pain (ACTonPain) log-in page. Screenshot 3: intro-duction to ACTonPain features. Screenshot 4: information concerning data security." 5-vi) Digital preservation webcitation.org Does your paper address subitem 5-vi?

5-vii) Access
Does your paper address subitem 5-vii? * "Reading and providing online informed consent and answering the survey took about 20-30 minutes. After completing the survey, the participants could choose to receive the unguided version of ACTonPain [22,55] by providing their email address in order to create to access ACTonPain." 5-viii) Mode of delivery, features/functionalities/components of the intervention and comparator, and the theoretical framework Does your paper address subitem 5-viii? * "The intervention group (IG) received AFI with a subsequent Web-based survey (homepage provided by the University of Freiburg, Germany); the control group (CG) filled out the same Web-based survey without receiving AFI. In this RCT, ran-domization took place before the assessment of eligibility and inclusion of partici-pants. We chose this procedure as it allowed us to send an invitation email provid-ing a link to the survey in either the IG or CG condition. " 5-ix) Describe use parameters Does your paper address subitem 5-ix? "ACTonPain consists of an introduction and 7 consecutive modules. The intervention targets core change processes proposed by Hayes et al [56] and is described in more detail by Lin et al [55]. Participants were advised to complete one session per week with a completion time of approximately 60 minutes. "

5-x) Clarify the level of human involvement
Does your paper address subitem 5-x? "After completing the questionnaire, participants were invited to receive ACTonPain treatment in an unguided version and without short message service (SMS) text messages (SMS Coach). This version of ACTonPain was provided without any human support and should be therefore of special interest for public health services due to its high scalability and low costs. " 5-xi) Report any prompts/reminders used Does your paper address subitem 5-xi? * "After completing the questionnaire, participants were invited to receive ACTonPain treatment in an unguided version and without short message service (SMS) text messages (SMS Coach). " 6a) Completely defined pre-specified primary and secondary outcome measures, including how and when they were assessed 5-xii) Describe any co-interventions (incl. training/support) Does your paper address subitem 5-xii? * "All participants had full access to treatment as usual." Page 16 of 33 CONSORT-EHEALTH (V 1.6.1) -Submission/Publication Form 12.07.2018 https://docs.google.com/forms/d/e/1FAIpQLSfZBSUp1bwOc_OimqcS64RdfIAFvmr... Does your paper address CONSORT subitem 6a? * "Primary Outcomes The primary outcomes were acceptance, uptake, and adherence. Acceptance: We operationalized acceptance on the basis of the wellestablished uni-fied theory of acceptance and use of technology (UTAUT [66,67]). This framework provides a reliable theoretical basis of drivers and barriers for users' acceptance of information technology [66-68] and has been used in numerous IMIs studies [27,47,65,[69][70][71][72]]. The UTAUT model postulates acceptance as the intention to use technology and the proximal predictor for actual use [73]. The items of the UTAUT acceptance were developed based on previous studies [46,47]. The sum score of the scale ranges from 4 to 20, and the 3 levels of acceptance can be categorized: low (sum score: 4-9), moderate (sum score: 10-15), and high (sum score: 16-20). The Cronbach alpha in this study was relatively low at.71. Table 1 provides an overview of the items for acceptance and predictors of acceptance (see secondary outcomes) in this study, including their scales.
Uptake: We operationalized uptake as log-in (yes or no) to IMI assessed 4 months after intervention access. The period of 4 months was chosen, as this should have been enough time for the participants to start with the intervention and work through all 8 modules. We assumed that 4 months after intervention access is a reasonable time to assess uptake and adherence. Adherence: We operationalized adherence as the number of completed modules of the intervention assessed 4 months after intervention access. Table 1. Items of acceptance and predictors of acceptance according to the unified theory of acceptance and use of technology model.

Secondary Outcomes
The secondary outcomes were the predictors of acceptance according to UTAUT as well as internet anxiety. Predictors of acceptance: According to the UTAUT model, there are 4 key predictors of either the behavioral intention or usage behavior of IT: performance expec-tancy, effort expectancy, social influence, and facilitating conditions [67]. The items measuring the construct's performance expectancy and effort expectancy were drawn from Vance et al [74]. The items for social influence and facilitating conditions were adapted from Venkatesh et al [67]. Internet anxiety: Two items for internet anxiety were adapted from Venkatesh et al [67] ("1. The internet is something threatening to me" and "2. I am afraid of making an irrevocable mistake while using the internet"). The items were rated on a 5-point Likert scale ranging from 1 "does not apply at all" to 5 "applies completely." The Cronbach alpha in this study was at.69." 6a-i) Online questionnaires: describe if they were validated for online use and apply CHERRIES items to describe how the questionnaires were designed/deployed Does your paper address subitem 6a-i? see above 6b) Any changes to trial outcomes after the trial commenced, with reasons 7a) How sample size was determined NPT: When applicable, details of whether and how the clustering by care provides or centers was addressed 6a-ii) Describe whether and how "use" (including intensity of use/dosage) was defined/measured/monitored Does your paper address subitem 6a-ii? see above 6a-iii) Describe whether, how, and when qualitative feedback from participants was obtained Does your paper address subitem 6a-iii?
Does your paper address CONSORT subitem 6b? * no 7a-i) Describe whether and how expected attrition was taken into account when calculating the sample size 7b) When applicable, explanation of any interim analyses and stopping guidelines 8a) Method used to generate the random allocation sequence NPT: When applicable, how care providers were allocated to each trial group 8b) Type of randomisation; details of any restriction (such as blocking and block size) 9) Mechanism used to implement the random allocation sequence (such as sequentially numbered containers), describing any steps taken to conceal the sequence until interventions were assigned Does your paper address subitem 7a-i? "To detect differences between IG and CG regarding acceptance, uptake, adherence, and the predictors of acceptance as well as internet anxiety, we conducted t-tests for independent samples and chi-square tests. In case of significant group differences, standardized mean differences (Cohen d) with a 95% CI were computed to quantify the effect. As this study includes multiple primary outcomes, we used a Bonferroni adjustment for the p-values of.016 (3 tests at an alpha level of.05). This procedure resulted in sufficient statistical power with the sample to detect differences between the two conditions that were larger than Cohen d=0.65." Does your paper address CONSORT subitem 7b? * not applicable Does your paper address CONSORT subitem 8a? * "For allocation to IG or CG, a computer-generated list of random numbers with randomly varying block sizes of 4, 6, and 8 was used by BF (www.sealedenvelope.com). IG watched an AFI video before answering the Webbased questionnaire. CG filled out the questionnaire immediately. Out of 489 potential participants, 115 provided informed consent and fulfilled the inclusion criteria ( Figure 1)." Does your paper address CONSORT subitem 8b? * "For allocation to IG or CG, a computer-generated list of random numbers with randomly varying block sizes of 4, 6, and 8 was used by BF (www.sealedenvelope.com)." 10) Who generated the random allocation sequence, who enrolled participants, and who assigned participants to interventions 11a) If done, who was blinded after assignment to interventions (for example, participants, care providers, those assessing outcomes) and how NPT: Whether or not administering co-interventions were blinded to group assignment Does your paper address CONSORT subitem 9? * "The intervention group (IG) received AFI with a subsequent Web-based survey (homepage provided by the University of Freiburg, Germany); the control group (CG) filled out the same Web-based survey without receiving AFI. In this RCT, randomization took place before the assessment of eligibility and inclusion of partici-pants. We chose this procedure as it allowed us to send an invitation email provid-ing a link to the survey in either the IG or CG condition. This is a case of randomiza-tion before data are available to confirm the individuals' eligibility without risking bias in the analysis [54]." "For allocation to IG or CG, a computer-generated list of random numbers with randomly varying block sizes of 4, 6, and 8 was used by BF (www.sealedenvelope.com)." Does your paper address CONSORT subitem 10? * "For allocation to IG or CG, a computer-generated list of random numbers with randomly varying block sizes of 4, 6, and 8 was used by BF (www.sealedenvelope.com)." 11a-i) Specify who was blinded, and who wasn't Does your paper address subitem 11a-i? * Participants could not be blinded to study conditions, the allocation was concealed from participants and researchers involved in recruitment 11a-ii) Discuss e.g., whether participants knew which intervention was the "intervention of interest" and which one was the "comparator" 11b) If relevant, description of the similarity of interventions (this item is usually not relevant for ehealth trials as it refers to similarity of a placebo or sham intervention to a active medication/intervention) 12a) Statistical methods used to compare groups for primary and secondary outcomes NPT: When applicable, details of whether and how the clustering by care providers or centers was addressed 12b) Methods for additional analyses, such as subgroup analyses and adjusted analyses Does your paper address subitem 11a-ii? participants were blinded and did not know whether they were receiving AFI or not Does your paper address CONSORT subitem 11b? * not applicable Does your paper address CONSORT subitem 12a? * "To detect differences between IG and CG regarding acceptance, uptake, adherence, and the predictors of acceptance as well as internet anxiety, we conducted t-tests for independent samples and chi-square tests. In case of significant group differences, standardized mean differences (Cohen d) with a 95% CI were computed to quantify the effect. As this study includes multiple primary outcomes, we used a Bonferroni adjustment for the p-values of.016 (3 tests at an alpha level of.05). This procedure resulted in sufficient statistical power with the sample to detect differences between the two conditions that were larger than Cohen d=0.65." 12a-i) Imputation techniques to deal with attrition / missing values Does your paper address subitem 12a-i? * "The descriptive statistics were based on nonimputed data, while all following analyses were conducted after multiple imputations with 20 imputations using the imputation algorithm implemented in SPSS (intention-to-treat analysis)."

X26) REB/IRB Approval and Ethical Considerations [recommended as subheading under "Methods"] (not a CONSORT item)
Does your paper address CONSORT subitem 12b? * "To examine potential subgroup differences (age, gender, education, pain duration and intensity, prior or present psychological intervention, internet usage and anxiety, and physical and emotional functioning) regarding acceptance, uptake, and adherence, exploratory analyses are provided (mean, SD, t-tests, and chi-square test). For this purpose, variables were dichotomized using defined cutoffs (gender, pain duration, education, and psychological intervention) or a median split (age, pain intensity, internet usage and anxiety, physical and emotional functioning, and level of acceptance regarding uptake and adherence). Note that the results of the subgroup analyses and analysis on secondary outcomes are exploratory and underpowered; adjusting for multiple testing would not be meaningful [75]." "Of 489 persons, 141 responded to the invitation. After we excluded those who did not provide informed consent (n=22) or did not fulfill the inclusion criteria (n=4), we included 57 and 58 participants in IG and CG, respectively. The missing value was between 0% and 5.7% per variable, and Little's Missing Completely at Random test indicated that the data were missing at random 14b) Why the trial ended or was stopped (early) 15) A table showing baseline demographic and clinical characteristics for each group NPT: When applicable, a description of care providers (case volume, qualification, expertise, etc.) and centers (volume) in each group Does your paper address CONSORT subitem 14a? * "The recruitment took place in September 2015" "Uptake: We operationalized uptake as login (yes or no) to the IMI assessed 4 months after intervention access.

X26-i) Comment on ethics committee approval
Adherence: We operationalized adherence as number of completed modules of the intervention assessed 4 months after intervention access. " 14a-i) Indicate if critical "secular events" fell into the study period Does your paper address subitem 14a-i? There were no "secular events" dring the study period Does your paper address CONSORT subitem 14b? * The trial stopped -as planned -when the invitation mail was sent to all potential participants Does your paper address CONSORT subitem 15? * see Table 2. Sociodemographic and clinical characteristics and internet usage.

15-i) Report demographics associated with digital divide issues
Does your paper address subitem 15-i? * Table 2. Sociodemographic and clinical characteristics and internet usage. 16) For each group, number of participants (denominator) included in each analysis and whether the analysis was by original assigned groups 17a) For each primary and secondary outcome, results for each group, and the estimated effect size and its precision (such as 95% confidence interval) 16-i) Report multiple "denominators" and provide definitions Does your paper address subitem 16-i? * "There was no significant (P>.016) difference between IG and CG with regard to acceptance, uptake, or adherence. Among the total sample, 9% (10/115) showed a low, 59% (68/115) a moderate, and 31% (36/115) a high level of acceptance, with an average sum score of 13.76 (SD 3.54). Figure 3 displays the levels of acceptance in both groups. The participants who applied for access to ACTonPain numbered 48 in IG and 50 in CG. Note that 9% (5/57) and 10% (6/58) of participants in IG and CG, respectively, did not complete the survey and therefore did not indicate whether they wanted to receive the intervention. Then, 7% (4/57) and 3% (2/58) of participants in IG and CG, respectively, did not want to receive the intervention, and 84% (48/57) and 86% (50/58) of participants in IG and CG, respectively, signed up to receive the intervention. Four months after receiving access to ACTonPain, 65% (75/115) of the sample had logged in. This represents an uptake rate of 68% (38/57, IG) and 62% (36/58, CG). With regard to adherence, the participants completed 1.09 (SD 1.72) modules on average, that is, the average participant only completed the introduction module. The results showed that 5% (6/115) participants did not complete any modules after log-in and 3% (4/115) completed all the modules in the study. Hence, the treatment dropout rate was at 97% (111/115). Figure 4 presents the number of log-ins and completed modules in each group."

16-ii) Primary analysis should be intent-to-treat
Does your paper address subitem 16-ii? "The descriptive statistics were based on nonimputed data, while all following analyses were conducted after multiple imputations with 20 imputations using the imputation algorithm implemented in SPSS (intention-to-treat analysis)." 17b) For binary outcomes, presentation of both absolute and relative effect sizes is recommended 18) Results of any other analyses performed, including subgroup analyses and adjusted analyses, distinguishing prespecified from exploratory Does your paper address CONSORT subitem 17a? * "Differences between IG and CG in all outcomes are summarized in Table 3." "There was no significant (P>.016) difference between IG and CG with regard to acceptance, uptake, or adherence. " "There was no significant (P>.05) difference between IG and CG with regard to performance expectancy, effort expectancy, social influence, facilitating conditions, or internet anxiety (Table 2)." 17a-i) Presentation of process outcomes such as metrics of use and intensity of use Does your paper address subitem 17a-i? Usage is one of the primary outcomes: "Note that 9% (5/57) and 10% (6/58) of participants in IG and CG, respectively, did not complete the survey and therefore did not indicate whether they wanted to receive the intervention. Then, 7% (4/57) and 3% (2/58) of participants in IG and CG, respectively, did not want to receive the intervention, and 84% (48/57) and 86% (50/58) of participants in IG and CG, respectively, signed up to receive the intervention. Four months after receiving access to ACTonPain, 65% (75/115) of the sample had logged in. This represents an uptake rate of 68% (38/57, IG) and 62% (36/58, CG). With regard to adherence, the participants completed 1.09 (SD 1.72) modules on average. That is, the average participant only completed the introduction module. The results showed that 5% (6/115) participants did not complete any modules after log-in and 3% (4/115) completed all the modules in the study. Hence, the treatment dropout rate was at 97% (111/115). Figure 4 presents the number of log-ins and completed modules in each group." Does your paper address CONSORT subitem 17b? * "Four months after receiving access to ACTonPain, 65% (75/115) of the sample had logged in. "

19) All important harms or unintended effects in each group
(for specific guidance see CONSORT for harms) Does your paper address CONSORT subitem 18? * "Since there were no group effects, we conducted the subgroup analyses with no group consideration in order to increase the power of the analyses. Participants with lower internet anxiety and higher anxiety symptoms showed significantly higher acceptance than their equivalent counterparts (Table 4).
With regard to up-take rates, more participants with higher depressive symptoms (75%, 45/60) and acceptance (80%, 47/59) logged into the platform than those with lower depres-sive symptoms (55%, 30/55) and acceptance (50%, 28/56). We also found that participants with a higher level of acceptance completed more modules compared with participants with a lower level of acceptance (1.43 vs 0.72 modules). "

18-i) Subgroup analysis of comparing only users
Does your paper address subitem 18-i? "To examine potential subgroup differences (age, gender, education, pain duration and intensity, prior or present psychological intervention, internet usage and anxiety, and physical and emotional functioning) regarding acceptance, uptake, and adherence, exploratory analyses are provided (mean, SD, t-tests, and chi-square test). For this purpose, variables were dichotomized using defined cutoffs (gender, pain duration, education, and psychological intervention) or a median split (age, pain intensity, internet usage and anxiety, physical and emotional functioning, and level of acceptance regarding uptake and adherence). Note that the results of the subgroup analyses and analysis on secondary outcomes are exploratory and underpowered; adjusting for multiple testing would not be meaningful [75]." Does your paper address CONSORT subitem 19? * harms or unintended effects are not expected and not reported in an earlier study on the same intervention 19-i) Include privacy breaches, technical problems DISCUSSION 22) Interpretation consistent with results, balancing benefits and harms, and considering other relevant evidence NPT: In addition, take into account the choice of the comparator, lack of or partial blinding, and unequal expertise of care providers or centers in each group Does your paper address subitem 19-i? no 19-ii) Include qualitative feedback from participants or observations from staff/researchers Does your paper address subitem 19-ii? no 22-i) Restate study questions and summarize the answers suggested by the data, starting with primary outcomes and process outcomes (use) Does your paper address subitem 22-i? * "Principal Findings To the best of our knowledge, this study is the first to examine the impact of AFI on patients' acceptance, actual uptake, and adherence of an IMI. AFI consisted of a short informational video. In this study, the average level of acceptance indicated a moderate to high acceptance in the sample (mean 13.76, SD 3.54) with no group differences between IG and CG. This acceptance level is higher than the levels examined in equivalent previous studies [42,46,47]. In these studies, acceptance levels in the intervention group after receiving IMI were at a mean of 11.42 (SD 4.28), 12.17 (SD 4.22), and 10.55 (SD 4.69)  "Therefore, future research should be conducted within naturalistic settings with more representative samples. Further, strategies to increase adherence in IMIs need to be developed involving IMI users, developers, and providers."

20-i) Typical limitations in ehealth trials
Does your paper address subitem 20-i? * "Limitations Several limitations in this study are noteworthy. First, the recruiting strategy might have influenced the way the participants filled out the survey, and their answers might have been more socially desirable. Consequently, the results on acceptance and uptake might not be representative for the population of patients with chronic pain, but they are likely to be representative for the population of patients with chronic pain in previous efficacy trials on IMIs for chronic pain. Hence, this study provides information on participants' acceptance in efficacy studies that can be useful for the interpretation of their respective results. This is especially the case regarding their generalizability to routine clinical practice given that most of these studies are conducted under ideal circumstances with highly specified inclusion and exclusion criteria [76].
In connection with the abovementioned lack of implementation facilitating factors in our AFI, a further limitation of this study is that it is only based on the UTAUT model. The UTAUT model and other equivalent models on the acceptance of IMIs as evaluated in a previous study [74], as well as in some empirical studies [27,53], suggest a relationship between acceptance and IMI use but might not consider sus-tained use, which is required in IMIs. Therefore, the findings of our study indicate that adherence facilitating factors are crucial even when acceptance is high. Hence, future research is needed to test interventions aimed at increasing adherence. HAPA can serve as an intervention model.
Finally, the reliability of the acceptance scale was relatively low at.71 compared with previous studies (Cronbach alpha ranged from.84 [42] to.87 [46,47]). Howev-er, the Cronbach alpha in this study is still in an acceptable range, especially as the scale consists of only 4 items [87]." 21) Generalisability (external validity, applicability) of the trial findings NPT: External validity of the trial findings according to the intervention, comparators, patients, and care providers or centers involved in the trial

21-i) Generalizability to other populations
Does your paper address subitem 21-i? "The comparatively high acceptance in both groups of this study is potentially due to selective sampling. We recruited the participants from a pool of persons who had already expressed interest in participating in a previous study on ACTonPain. After the end of recruitment for the main study, we invited all persons who were not randomized in the study to participate in this study and to receive ACTonPain as an incentive after completion of the survey. Hence, the participants in this study expressed their interest for ACTonPain twice. Therefore, the level of acceptance most likely reflects the acceptance and uptake in many IMI efficacy studies consist-ing of a population that is considerably more interested and open to IMIs than the general population [76]." 21-ii) Discuss if there were elements in the RCT that would be different in a routine application setting Does your paper address subitem 21-ii? "The comparatively high acceptance in both groups of this study is potentially due to selective sampling. We recruited the participants from a pool of persons who had already expressed interest in participating in a previous study on ACTonPain. After the end of recruitment for the main study, we invited all persons who were not randomized in the study to participate in this study and to receive ACTonPain as an incentive after completion of the survey. Hence, the participants in this study expressed their interest for ACTonPain twice. Therefore, the level of acceptance most likely reflects the acceptance and uptake in many IMI efficacy studies consist-ing of a population that is considerably more interested and open to IMIs than the general population [76]. Therefore, our previous work on acceptance in the general population [42,46,47] might give us a more realistic estimate of acceptance. By comparing the acceptance rates throughout the studies, this study quantifies how acceptance and uptake rates can differ between populations in efficacy studies and routine health care settings."