Parts of this chapter have been reproduced from Kipping et al.1 This is an Open Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY 4.0) license, which permits others to distribute, remix, adapt and build upon this work, for commercial use, provided the original work is properly cited. See: http://creativecommons.org/licenses/by/4.0/.
In this chapter the feasibility study aims and objectives, study design, progression criteria, trial registration, governance, ethics, safety and public involvement are outlined.
Study aim and objectives
The aim of the feasibility study was to evaluate the feasibility and acceptability of implementing and trialling an adaptation of the NAP SACC intervention, with a home component in nursery settings. The study had one primary objective and three secondary objectives.
Primary objective
- To assess whether or not prespecified criteria relating to the feasibility and acceptability of the intervention and trial design are met sufficiently for progression to a full-scale RCT.
Secondary objectives
- To explore the experiences of nursery staff, the intervention delivery team and parents/carers, in terms of acceptability, barriers, fidelity to and facilitators of the intervention, data collection methods and participant burden, and the feasibility of long-term follow-up with the aim of informing refinement of the intervention and study design prior to a potential full-scale RCT.
- To pilot primary and secondary outcome measures and economic evaluation methods, and determine the practicality of data linkage for BMI through the Child Measurement Programme in England66 and Wales,67 in advance of a potential full-scale RCT.
- To calculate the sample size required for a full-scale RCT and to estimate likely recruitment, attendance, adherence and retention rates.
Feasibility study design
The feasibility study had two phases:
- Phase 1: intervention adaptation and development, in which the NAP SACC materials were adapted for use in the UK and the NAP SACC UK home component to involve parents/carers was created.
- Phase 2: feasibility cluster RCT with embedded process evaluation and health economic methods (Figures 1 and 2). The logic model for the NAP SACC UK intervention is shown in Figure 3.
FIGURE 1 Phase 1 flow diagram. (Figure not reproduced here; see the original article.)
FIGURE 2 Phase 2 flow diagram. (Figure not reproduced here; see the original article.)
FIGURE 3 Logic model of NAP SACC UK. IOTF, International Obesity Task Force. (Figure not reproduced here; see the original article.)
The protocol for the study has been published.1
Progression criteria
The predefined progression criteria for the trial, as agreed with the external Trial Steering Committee (TSC) and the funder [National Institute for Health Research (NIHR)], were the following.
Criterion 1: feasibility
- Was it feasible to implement the NAP SACC UK intervention in child-care providers? This was assessed according to (1) at least 40% of contacted eligible child-care providers expressing a willingness in principle to take part in the feasibility trial in response to an invitation to take part; and (2) a synthesis from the different aspects of the process evaluation [observation, interviews and analysis of meeting logs between NAP SACC UK partners (health visitors) and child-care providers].
Criterion 2: acceptability of intervention
- Was the intervention acceptable to NAP SACC UK partners? This was assessed via interviews with partners and analysis of meeting logs between NAP SACC UK partners and child-care providers.
- Was the intervention acceptable to the majority of child-care managers, staff and parents/carers? This was assessed via interviews with managers, staff and parents/carers.
Criterion 3: acceptability of the trial design
- Were the trial design and methods acceptable? This was assessed according to (1) expressions of interest from eligible child-care settings; (2) interviews with child-care providers about randomisation and data collection; (3) at least a 40% parental opt-in consent rate for measurements with eligible 2- to 4-year-old children; (4) a maximum loss to follow-up of three providers (or no more than two in any arm) or 40% of children; (5) a synthesis of interviews with parents/carers about data collection.
Trial registration, governance and ethics
The study was approved by Wales Research Ethics Committee 3 prior to recruitment and data collection commencing (formative work 14/WA/1134; pilot RCT 15/WA/0043; process evaluation 15/WA/035). The trial protocol was registered with Current Controlled Trials (ISRCTN16287377: www.isrctn.com/ISRCTN16287377). Ethics approval for the mediator questionnaire substudy was obtained from the Faculty of Health Sciences Research Ethics Committee at the University of Bristol (reference 41585). Ethics approval for the nursery food photography feasibility substudy was obtained from the University of Bristol School for Policy Studies Research Ethics Committee in November 2017. The feasibility RCT was overseen by a TSC, comprising an independent chairperson and four independent members. The TSC met approximately 6-monthly throughout the study (with one 12-month gap), meeting five times in total, to examine trial progress, conduct and scientific credibility. This was a pilot trial with no interim analysis and, therefore, the TSC and funder agreed that a separate Data Monitoring and Safety Committee was not necessary.
Safety
Child-care providers were given contact details for the trial manager and were able to contact the study team if they had any concerns or parents/carers report concerns. Nursery managers and those delivering the intervention (health visitors and trainers) were asked to contact the study team within 5 working days if any untoward incident or adverse event (AE) occurred to a member of staff or child, as a direct result of taking part in NAP SACC UK, or because of changes that have occurred in the nursery environment as a result of participation in NAP SACC UK. Study-specific AE/incident report forms were available to be used to record information on the event. No AEs or serious AEs were reported associated with the intervention or trial.
Public involvement
A patient and public involvement group was set up early in the project to provide advice and guidance. Parents, child-care staff, health visitors, local authority early years staff, public health specialists, health improvement staff and a dietitian were invited to participate. The first meeting was held in March 2015, during phase 1 of the project, as phase 2 (a feasibility RCT) was being planned. The topics discussed included the wording of parent questionnaires, wording of the questionnaire around future use of anonymised data, the content and delivery of the nursery staff workshops that made up a key component of the intervention, the home component, ‘NAP SACC at Home’, and suitable thank you gifts for the children involved. This first meeting was well attended (nine lay members). The next meeting, held in February 2016 with the same group invited, was very poorly attended (one lay member). This meeting was held after baseline data collection, prior to the intervention. The main topic for discussion was the home component, ‘NAP SACC at Home’, particularly how to engage parents and children, the suitability of sending tips by text and e-mail, how to encourage parents to set goals, and the use of a NAP SACC UK Facebook group.
The final meeting was held in July 2017 at the end of the study. This time only nursery managers were invited (five attended) and the meeting was used to discuss improvements that could be made to the NAP SACC intervention and data collection methods following issues identified during the feasibility study. Topics discussed included how to approach nurseries and parents to improve recruitment, incentives for nurseries to participate, dietary measures and the possibility of weighing or photographing food consumed by children, intervention delivery and the impact of the government-funded 30 hours of child care due to start in September 2017. This was a very useful meeting with good engagement from nursery managers, who provided useful insights.
Changes made to the protocol and intervention following phase 1
Change of phase 2 study site
During the funding process, NIHR suggested that an urban area with greater ethnic diversity be included in addition to North Somerset to ensure greater generalisability. The plan was to keep Bristol available for a full trial and, therefore, we proposed that Cardiff be involved. There was subsequently a change of site from Cardiff to Gloucestershire, which required a protocol amendment. Full details of this decision are shown in Table 30, Appendix 1. This was agreed with the sponsor, TSC and NIHR. The collaborators’ agreement was signed by the two new organisations. This created a delay in recruitment of nurseries in Gloucestershire, but the change improved our understanding of the feasibility of undertaking this study by involving another local authority area in England given the complexity of interventions and different nursery provision encountered in Wales.
Shortening the intervention
As recruitment of nurseries was delayed by the change to include Gloucestershire, we agreed with the TSC to shorten the intervention to 5 months. Therefore, baseline data collection was carried out from September 2015 to January 2016. Randomisation took place in February 2016. The intervention period was 1 February 2016 to 30 June 2016. The NAP SACC UK at Home element was launched to parents in April and May 2016. Follow-up data collection was completed at 8 out of the 12 nurseries in July 2016. The remaining four nurseries were left until September 2016 to assess the feasibility of following up those children who had left nursery to start school.