Let It Out (LIO) study: protocol for a mixed-methods study to optimise the design and assess the feasibility of an online emotional disclosure-based intervention in UK hospices

Introduction The current COVID-19 pandemic has forced hospices to look for more ways to support people remotely, including psychological support. Emotional disclosure-based interventions hold potential as a way of providing support remotely. However, evidence of their efficacy in people with terminal illness is mixed. Reviews have highlighted this may be due to interventions not being tailored to the unique needs of this population. In response to this, we are developing Let It Out (LIO), an online, self-guided emotional disclosure-based intervention tailored for people living with terminal illness. Aims The primary objective of the study is to optimise the design of the LIO intervention. Secondary objectives include assessing its acceptability and feasibility; exploring potential impact on well-being; identifying potential adverse effects; and informing choice of outcome measures for potential future evaluation. Methods and analysis A single arm, mixed-methods, multisite, longitudinal study. Up to 40 people living with a terminal illness under the care of hospices in England and Scotland will receive the online LIO intervention. LIO consists of 3, self-guided expression sessions over 2 weeks. The primary outcome measures are (1) a structured feedback form completed by participants after the final expression session; and (2) semi-structured interviews and focus groups with ≤15 patient participants, ≤30 hospice staff and ≤15 informal carers. These quantitative and qualitative data will be triangulated via process evaluation to inform optimisation of the intervention design. Secondary outcome measures include validated measures of physical and psychological health collected at baseline and after the final expression session (immediately, 1, 4 and 8 weeks after); and data on recruitment, retention and fidelity. Ethics and dissemination The study is approved by the University College London Research Ethics Committee (reference: 15281/002). The findings will be shared through peer-reviewed scientific journals and conferences, and traditional, online and social media platforms.

P4 Method -please state that you employ a mixed methods design. Please describe shortly how quantitative and qualitative data will be integrated since you have a mixed methods design.
The scientific rationale for conducting the study is well described.
The primary objectives and secondary objectives 1-4 are clear. However, please clarify the relevance of secondary objective 5. P 5 Do you have a sequential or convergent mixed methods design? Will quantitative data inform the qualitative data collection?
Several places you use the less than or equal to sign regarding number of hospice and number of participants.
Could this be revised to avoid confusion? P9, L 42 what does PPI representatives mean? Please spell fully out first time you use.
Recruitment of group 1 for the intervention, convenience or consecutive or other type of sampling strategy? Recruitment of group 1 participants for interviews, purposeful or convenience or other type of sampling strategy? Please clarify. P 14, L49 SQS validated in palliative care populations? P 14, L58, Uptake of existing mental health service, has this form been validated? P 14-15 Uptake of existing mental health services -has this been validated in this population? P15 please describe shorty the topics you will explore in the interviews with group 2 and 3 P15, L50 will the recording be transcribed verbatim?
P16-17 Please elaborate more clearly on how you will integrate quantitative and qualitative data in data analysis and the results. This is essential for a mixed methods design.

GENERAL COMMENTS
Major Comments: -The authors describe the development and optimization of an online, self-guided emotional disclosure-based intervention, called Let It Out (LIO), tailored for people with terminal illness receiving hospice care. This manuscript describes their mixed-methods study protocol, which comes in advance of eventual evaluation of the intervention's efficacy. The relevance of the LIO intervention is highlighted by the current COVID era, when telehealth and other remote interventions are especially critical, and may extend beyond this period as well.
-In this well-written manuscript, the authors describe the gap in the literature regarding emotional disclosure interventions and how their protocol is an important next step in filling that gap.
-I found the manuscript and protocol to be of good quality, clear, well-referenced, and worthy of publication.
-I found it particularly valuable that the authors built-in several methods for monitoring participants' mood and wellbeing while engaging with the ED intervention, including a self-report mood questionnaire after each expression session and a phone call/email in week 2 from the research team to check-in on wellbeing. This is, of course, particularly important given the sensitive nature of the intervention's questions, prompts, and content.

First reviewer comments
This is a strong protocol. It is interesting to read.
One could consider a table highlighting how the data are cross walked with the theoretic construct for the study.
Thank you for your positive feedback on the protocol -we are glad you found it of interest. In response to your comment regarding linking the theoretic construct with the data being collected (and to some of the feedback from reviewer 2, and the editors) we have developed Table 3. The aim of this table is to provide an at-a-glance, visual summary of how in this study, guided by a pragmatic research philosophy, we plan to integrate multimodal data to inform the optimisation of the intervention, such that it is tailored for practical implementation in a real-world setting.

An interesting and mostly well written protocol
Thank you for this feedback. We appreciate your detailed and thoughtful critique and have tried to address each point. Your guidance has certainly resulted in a stronger, more coherent protocol.

P4, L30 immediately after -after what? Please clarify
We have changed the phrasing to clarify we mean immediately after the last intervention session (Line 31).
P4 Method -please state that you employ a mixed methods design. Please describe shortly how quantitative and qualitative data will be integrated since you have a mixed methods design.
We have included a statement that this is a mixed methods design in the title, Methods section of the abstract, and in the Design subsection of the Methods and Analysis section. In the abstract, we have noted that the mixed-methods data will integrated using process evaluation to triangulate the data, and provided more detail on this integration method in the Methods section (Lines 115-121, 372 -387, Table 3).
The scientific rationale for conducting the study is well described. The primary objectives and secondary objectives 1-4 are clear. However, please clarify the relevance of secondary objective 5. We have updated the manuscript to clarify this (Lines 115 -123).
Thank you for noticing this. We have replaced the term as advised (Line 117).
Several places you use the less than or equal to sign regarding number of hospice and number of participants. Could this be revised to avoid confusion?

Thank you for spotting this. We have spelt this out as Patient and Public Involvement (PPI) (Line 190).
Recruitment of group 1 for the intervention, convenience or consecutive or other type of sampling strategy? Recruitment of group 1 participants for interviews, purposeful or convenience or other type of sampling strategy? Please clarify.
For Group 1 recruitment, we will employ convenience sampling as a pragmatic decision in light of the difficulties opening sites and relative unknowns of recruiting during the COVID-19 pandemic (Line 148). In the initial phase of the study, all Group 1 participants will be invited to take part in the study interview; after one third (n=5) have been recruited, we will assess the mix of participants in terms of demographic characteristics, to inform recruitment targets according to a pre-defined purposive sampling framework (Line 172-175).

P 14, L49 SQS validated in palliative care populations?
This is a relatively newly developed measure (published in 2018) and to our knowledge, it has not been validated in palliative care populations. We chose it specifically to minimise any burden that could be associated with the more widely validated, but significantly longer, questionnaires such as the Pittsburgh Sleep Quality Index. We were particularly cautious as this is just one of several measures being administered, and we therefore did not want to over-burden participants.
P 14, L58, Uptake of existing mental health service, has this form been validated?
No, this is a form that was developed specifically for this study to provide insight into whether people have, or intend to, request help from mental health services. This is clarified in Table 1 in the description of the measure. P 14-15 Uptake of existing mental health services -has this been validated in this population?
As described above, no, this is not a validated measure, but a form developed specifically for this study by the research team.
P15 please describe shorty the topics you will explore in the interviews with group 2 and 3

We have added a brief overview of the topics covered on 361 -365 (including views on the intervention content and design, potential risks or benefits, where the intervention could fit into current pathways of care and what may needed to support its implementation).
P15, L50 will the recording be transcribed verbatim?
Yes, the recording will be transcribed verbatim. This is now stated on Lines 282 and 368.
P16-17 Please elaborate more clearly on how you will integrate quantitative and qualitative data in data analysis and the results. This is essential for a mixed methods design.
In the original version of this manuscript that we first submitted, we stated that quantitative and qualitative data would be triangulated/integrated through process evaluation, and that we would use the findings of the process evaluation to inform the optimisation of the intervention. To clarify this integration process, we have provided a summary table (Table 3) describing how each type of data will be analysed in accordance with our process evaluation framework. We created the framework based on the examples provided in the Medical Research Council (MRC) guidance on conducting process evaluations. We hope this provides sufficient clarity on how the data will be integrated.

Third reviewer comments
The authors describe the development and optimization of an online, self-guided emotional disclosure-based intervention, called Let It Out (LIO), tailored for people with terminal illness receiving hospice care. This manuscript describes their mixed-methods study protocol, which comes in advance of eventual evaluation of the intervention's efficacy. The relevance of the LIO intervention is highlighted by the current COVID era, when telehealth and other remote interventions are especially critical, and may extend beyond this period as well.
In this well-written manuscript, the authors describe the gap in the literature regarding emotional disclosure interventions and how their protocol is an important next step in filling that gap.
I found the manuscript and protocol to be of good quality, clear, well-referenced, and worthy of publication.
I found it particularly valuable that the authors built-in several methods for monitoring participants' mood and wellbeing while engaging with the ED intervention, including a self-report mood questionnaire after each expression session and a phone call/email in week 2 from the research team to check-in on wellbeing. This is, of course, particularly important given the sensitive nature of the intervention's questions, prompts, and content.
Thank you very much for your positive feedback; it is really encouraging that you can see the value in our work, and appreciate the thought that has gone into designing the built-in methods to monitor participants' mood.

GENERAL COMMENTS
The authors have responded to the reviewers' comments/suggestions. The manuscript is improved.