Does personalising a study invitation letter by including a potential participants’ name and address improve study recruitment?

ISRCTN	ISRCTN18404129
DOI	https://doi.org/10.1186/ISRCTN18404129
ClinicalTrials.gov (NCT)	Nil known
Clinical Trials Information System (CTIS)	Nil known
Protocol serial number	Version 1
Sponsor	Uppsala University
Funders	Vetenskapsrådet, Cancerfonden, Barncancerfonden

Submission date: 19/11/2019
Registration date: 25/11/2019
Last edited: 11/11/2022

Recruitment status: No longer recruiting
Overall study status: Completed
Condition category: Other

Prospectively registered

Protocol

Statistical analysis plan

Results

Individual participant data

Plain English summary of protocol

Background and study aims
Recruiting participants into trials can be challenging and many trials fail to recruit in time and to the target sample size. Recruiting into mental health trials can be particularly difficult. Recruitment difficulties may result in a waste of public funding, reduce statistical power and validity and impact negatively on patient health. Despite this, little is known about how to design efficient recruitment strategies and the identification of evidence-based recruitment strategies is therefore needed. A potential solution is to combine results from similar well-designed and well-reported recruitment studies with a trial (SWATs) embedded in different trials.
Research indicates that addressing people by name may increase the likelihood of the person responding, which has been shown for different populations and in different settings, for example breast cancer survivors invited to partake in a behaviour change intervention, persons encouraged to pay a delinquent fine via text message, and members of the public invited to complete postal questionnaires. However, few of these studies have used a randomised controlled design (RCT) in the area of clinical healthcare research. In addition, the latest review of strategies to improve recruitment into RCTs did not identify any interventions evaluating the personalisation of study invitation letters.
This SWAT will evaluate the effectiveness of a personalised study invitation letter including the potential participant's name and address, compared with a standard, non-personalised study invitation letter (without name and address), on participant recruitment rates into the ENGAGE study, a feasibility study of an internet-administered, guided, CBT-based, self-help intervention (ENGAGE) for parents of children previously treated for cancer.

Who can participate?
Parents of children diagnosed with cancer when aged 0-18 years, who have completed cancer treatment three months to five years previously, residing in Sweden

What does the study involve?
Two approaches will be used for recruitment into host study ENGAGE: (1) postal study invitations packs and; (2) advertisements placed on websites and social media (e.g., Facebook, Twitter, and Instagram). Target sample size is 50 participants. The embedded SWAT will be implemented only for postal invitations and all parents invited via postal invitation will be included.
Participants will be randomly allocated to receive one of the following interventions:
Intervention (1): Standard ENGAGE study invitation letter not including their name and address (control group)
Intervention (2) A personalised study invitation letter including their name and address (intervention group). The wording of the personalised invitation letter has been designed in consultation with the ENGAGE Parent Research Partners group, consisting of parents with lived experience of being a parent of a child treated for cancer.

What are the possible benefits and risks of participating?
Potential participants will not be aware they are part of an embedded trial evaluating a recruitment strategy and receiving a personalised or non-personalised letter. The researchers do not anticipate any risks associated with being part of this trial.

Where is the study run from?
Clinical Psychology in Healthcare, Department of Women's and Children's Health, Uppsala University (Sweden)

When is the study starting and how long is it expected to run for?
February 2020 to December 2020

Who is funding the study?
1. Vetenskapsrådet (Sweden)
2. Barncancerfonden (Sweden)
3. Cancerfonden (Sweden)

Who is the main contact?
1. Prof. Louise von Essen (scientific)
louise-von.essen@kbh.uu.se
2. Dr Joanne Woodford (scientific)
joanne.woodford@kbh.uu.se

Contact information

Prof Louise von Essen
Scientific

MTC-house
Akademiska sjukhuset
Uppsala
SE-75185
Sweden

ORCID ID	0000-0001-5816-7231
Phone	+46 (0)704250714
Email	louise-von.essen@kbh.uu.se

Dr Joanne Woodford
Scientific

MTC-house
Akademiska sjukhuset
Uppsala
SE-75185
Sweden

ORCID ID	0000-0001-5062-6798
Phone	+46 (0)729999 211
Email	joanne.woodford@kbh.uu.se

Study information

Primary study design	Interventional
Study design	Randomised controlled embedded trial design
Secondary study design	Randomised controlled trial
Study type	Participant information sheet
Scientific title	Study within a trial (SWAT) protocol. Investigating the effect of personalised versus non-personalised study invitations on recruitment: an embedded randomized controlled recruitment trial
Study acronym	ENGAGE: SWAT
Study objectives	This SWAT aims to evaluate the effectiveness of a personalised study invitation letter including the participant’s name and address compared with a standard, non-personalised study invitation letter on participant recruitment rates into the ENGAGE study (ISRCTN57233429). The researchers will examine a two-tailed hypothesis that sending the personalised study invitation letters to potential participants could cause benefit or loss to recruitment for the host trial.
Ethics approval(s)	Approved 07/08/2019, Swedish Ethical Review Authority (Etikprövningsmyndigheten, Box 2110, SE-750 02 Uppsala, Sweden; Tel:+46 (0)10475 08 00; Email: registrator@etikprovning.se), ref: 2019-03083
Health condition(s) or problem(s) studied	Recruitment to trials
Intervention	Children’s personal identification numbers will be obtained from the Swedish Childhood Cancer Registry (National Quality Registry) and linked to parents’ names and addresses via NAVET, a population registry held by the Swedish Tax Agency. Invitation packages, including invitation letters and information about the study will be sent to parents via post. Parents will be invited to participate randomly by the research team, using blocks of 100 until the target number of 50 has been reached. Invitations will not be sent to parents of deceased children. Participants will be randomised to receive one of the following interventions: Intervention (1): Standard ENGAGE study invitation letter not including their name and address (control group) Intervention (2): A personalised study invitation letter, including their name and address (intervention group) The wording of the personalised invitation letter has been designed in consultation with the ENGAGE Parent Research Partners group, consisting of parents with lived experience of being a parent of a child treated for cancer.
Intervention type	Other
Primary outcome measure(s)	The effectiveness of the personalised invitation letter compared with the standard invitation letter, defined as the recruitment rate, being the proportion of participants in each intervention group that are enrolled into the ENGAGE study.
Key secondary outcome measure(s)	The proportion of parents in each group: 1. Expressing an interest in participating in the ENGAGE study 2. Opting out of the ENGAGE study 3. Completing the reasons for non-participation questionnaire 4. Completing the eligibility interview 5. Completing the baseline assessment 6. Retained at (1) 12 weeks and (2) 6 months follow-up 7. Requiring a telephone reminder at (1) recruitment; (2) post-treatment (12 weeks); and (3) 6-months follow-up
Completion date	02/03/2021

Eligibility

Participant type(s)	Mixed
Age group	Adult
Lower age limit	18 Years
Sex	All
Target sample size at registration	50
Total final enrolment	56
Key inclusion criteria	Parents of children diagnosed with cancer when aged 0-18 years, who have completed cancer treatment three months to five years previously, residing in Sweden
Key exclusion criteria	Does not meet inclusion criteria
Date of first enrolment	02/03/2020
Date of final enrolment	02/09/2020

Locations

Countries of recruitment

Sweden

Study participating centre

Uppsala University

Clinical Psychology in Healthcare
Department of Women's and Children's Health
MTC-building
Akademiska sjukhuset Uppsala
Uppsala
SE-75185
Sweden

Results and Publications

Individual participant data (IPD) Intention to share	Yes
IPD sharing plan summary	Stored in repository
IPD sharing plan	The datasets generated during and/or analysed during the current study will be stored in a non-publically available repository. Repository name: Promoting the use of SWATs (PROMETHEUS) Programme. PROMETHEUS is a major national programme of research funded by the Medical Research Council (MRC) to facilitate the routine embedding of a methodology research study within a planned or ongoing trial. Link: https://www.york.ac.uk/healthsciences/research/trials/research/swats/prometheus/. After trial end date, a copy of the anonymised aggregate recruitment data will be shared with the PROMETHEUS team to allow a meta-analysis with data from similar host studies participating in the PROMETHEUS programme. Identifiers will be removed, and data will be randomly sorted to ensure that it would not be possible to re-identify participants in the dataset, in line with General Data Protection Regulation (GDPR) requirements. Potential participants included in the embedded recruitment trial will be blind to the study hypothesis and unaware they are part of an embedded trial. As such, consent to participate in the host trial will be obtained from participants, however, not for this embedded trial. Swedish Ethical Review Authority has granted approval for the embedded recruitment trial, 07/08/2019. ref: 2019-03083.

Study outputs

Output type	Details	Date created	Date added	Peer reviewed?	Patient-facing?
Results article		06/03/2022	08/03/2022	Yes	No
Protocol article	protocol	24/04/2020	19/05/2020	Yes	No
Participant information sheet	Participant information sheet	11/11/2025	11/11/2025	No	Yes

Editorial Notes

11/11/2022: The total final enrolment was added.
08/03/2022: Publication reference added.
19/05/2020: Publication reference added.
11/12/2019: The following changes have been made:
1. The recruitment start date has been changed from 01/02/2020 to 02/03/2020.
2. The recruitment end date has been changed from 30/09/2020 to 02/09/2020.
3. The overall trial end date has been changed from 30/12/2020 to 02/03/2021.
4. The intention to publish date has been changed from 03/03/2021 to 01/07/2021.
20/11/2019: Trial's existence confirmed by Swedish Ethical Review Authority.