Study design

3.2.1 The HELP trial and HELP 24m study

HELP trial

Randomised controlled trials (RCTs) are quantitative, controlled experiments which assess the effects of one or more interventions. A sample of the population of interest is selected, individuals are randomly assigned to one of the comparative groups, then followed up for a specified period of time.(337) Within a hierarchy of evidence quality, the RCT is considered to be able to provide the most reliable evidence on the ‘true effect’ of health interventions,

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because by using appropriate processes, such as randomisation, during the conduct of an RCT, the risk of confounding factors influencing the results can be minimised.(337)

Increasingly in healthcare settings the cluster RCT design is used, where groups of patients rather than individuals are randomised to comparative study groups.(338) The HELP study was a prospective cluster RCT, where maternity units (clusters), were randomly allocated to the intervention or control groups. Allocation concealment from the trial team and maternity units, until after maternity unit recruitment was complete, was used to help prevent the participation of clusters being influenced by group assignment. Pregnant women with obesity were subsequently recruited within these randomised clusters. The cluster RCT design was selected as it provided protection against contamination across trial groups within maternity units, avoiding confounding of the intervention effect through midwife care or participant to participant. The HELP trial used appropriate methods to achieve rigour in the study design, such as publishing a protocol paper which contained detailed reporting of trial methods, randomisation, allocation concealment, appropriate sample size powered to detect a minimally clinically important intervention effect, ITT analysis, and comparison of intervention groups on pre-specified clinically relevant study outcomes (Appendix B).(170) Due to the nature of the intervention, blinding of allocation was not possible, which may have increased the risk of differential treatment of trial groups or assessments of outcomes.

The MRC guidance on evaluating complex interventions recommends re-contacting study participants as a highly informative way to assess long-term outcomes from the original study, and to determine maintenance of any short-term changes.(237)

HELP 24m study

The HELP 24m study was a follow-up to the HELP trial with the aim of answering the research questions relating to long-term effectiveness of such the intervention. The follow-up time point was selected as there was a paucity of evidence on post-intervention outcomes for mothers and children beyond 12 months postpartum, and the aim was to understand the importance of the early child environment and health behaviours from the start of life, on weight trajectories for the child. The methods presented in this Chapter aim to demonstrate how rigour was intended to be retained within the HELP 24m study design.

3.2.2 Ethical approval and sponsorship

Participants in the HELP trial had only consented to participate in the study up to 12 months postpartum. Further approval was sought from the Health and Care Research Wales

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(HCRW) NHS Research Ethics Committee (REC) 3, to conduct a follow-up of these women at 24 months postpartum. As the management of the follow-up study differed to the trial management (i.e. PhD student), it had to be submitted for ethical approval as a new study.

The HELP 24m study was conducted in accordance with the recommendations for physicians involved in research on human participants adopted by the 18th World Medical Assembly, Helsinki 1964 and later revisions. Ethical approval was granted by the HCRW NHS REC 3 (Reference Number 13/WA/0017) on 27th February 2013. Two substantial amendments were submitted throughout the study (these are outlined in Appendix C). Cardiff University (CU) agreed to act as sponsor for the study, as required by the UK Research Governance Framework for Health and Social Care.(339)

3.2.3 Recruitment of local researchers to conduct data collection

Women eligible to take part in the study were located in 20 geographical areas within England and Wales, according to the location of maternity units in the HELP trial. Where possible, local researchers at sites were recruited to manage approach, consent and follow- up of women within these areas. The study aimed to recruit the local researchers who had supported data collection for the HELP trial, as continuity of researcher may encourage participants to take part and enable easier contact (340).

In England, previous local researchers were asked if they would be interested in conducting data collection at 24 months postpartum. Where these researchers declined to be involved, a different local researcher was sought by contacting the previous Principal investigator or the Head of Midwifery services.

In Wales, Health and Care Research Wales (HCRW) provide support in the delivery of research studies. The study was adopted on to the HCRW research portfolio, as per the process used for data collection in the Welsh sites in the HELP trial, and HCRW research officers were recruited to assist in data collection in the five Welsh study sites.

Where an appropriate local researcher could not be recruited, the student conducted the consent and collection of follow-up data from participants in these areas, assisted by Centre for Trials Research (CTR) administration staff who made initial contact with eligible women, invited them to take part and arranged home visits for the student to complete. For all sites, appropriate approvals were set up as described below.

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3.2.4 NHS and regulatory approvals

The HELP 24m study did not involve recruitment of NHS patients. However, where NHS staff intended to support approach, consent and follow-up of women, Research & Development (R&D) approvals were required from their health trust of employment, to agree responsibility for the work that was being undertaken on behalf of the study.

In England, the relevant R&D departments were contacted and the process for obtaining approvals in that health trust followed. Principal Investigators were identified locally to take responsibility for the study at sites, this was usually the local researcher who had agreed to support consent and data collection. Individual study agreements were drafted between the health trusts and the study sponsor, outlining responsibilities of each party and financial arrangements for follow-up data collection. The health trust was offered a payment of £45 for each participant follow-up successfully completed.

In Wales, global approvals through the NISCHR Permissions Co-ordinating Process (PCU) (now the HCRW permissions service) were sought. The aim of this service was to streamline the process of NHS permissions across Wales. Health trusts involved in the HELP trial were also contacted for local approvals.

The identification of local researchers and the process of obtaining R&D approvals, if appropriate, was prioritised according to the dates by which individuals, within clusters, reached the 24 months postpartum time point.